NISTIR 89-3925

DEVELOPMENT OF A

COMPUTER-CONTROLLED

HOT-DEFORMATION APPARATUS

AT NIST

Yi-Wen Cheng

Yair Rosenthal

Harry I. McHenry

National Institute of Standards and Technology

U.S. Department of Commerce

Boulder, Colorado 80303-3328

October 1989

N I STIR 89-3925

DEVELOPMENT OF A

COMPUTER-CONTROLLED

HOT-DEFORMATION APPARATUS

AT NIST

Yi-Wen Cheng

Yair Rosenthal'

Harry I. McHenry

Materials Reliability Division

Materials Science and Engineering Laboratory

National Institute of Standards and Technology

Boulder, Colorado 80303-3328

October 1989

^Guest worker, on leave from Nuclear Research Center-Negev, Beer Sheva, Israel

DEPARTMENT OF COMMERCE, Robert A. Mosbacher, Secretary

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, Raymond G. Kammer, Acting Director

CONTENTS

Page

LIST OF FIGURES v

ABSTRACT vii

I . INTRODUCTION 1

II. DESCRIPTION OF THE HOT -DEFORMATION APPARATUS 3

Loading System 3

Heating and Control System 5

Cooling and Control System 6

Vacuum System 6

Assembly for Dilation Measurement After Deformation 7

Computer and Peripherals 8

Computer Programs for System Control, Data Acquisition,

and Data Analysis 9

III. EXAMPLES OF USING THE APPARATUS 13

Direct-Quenching Simulation of ASTM A710 Steel 13

Studies of Directly Cooled Forging Steels 17

IV. CONCLUSIONS AND SUMMARY 21

V. ACKNOWLEDGMENTS 23

VI . REFERENCES 24

APPENDIX 1. Computer Program Listing for System Control and

Data Acquisition 52

APPENDIX 2. Computer Program Listing for

Post-Test Data Analysis 72

iii
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LIST OF FIGURES

Page

1 . Thermal and mechanical treatments in a thermomechanical

processing (TMP) simulation. 27

2. Hot-deformation apparatus. (a) overall view; (b) interior of

the vacuum chamber 28

3. The basic components of the hot-deformation apparatus 29

4. Drawing of the load train and the device for measurement of

length change during cooling and phase transformation 30

5. The responses of the servohydraulic actuator to commands of

various strain rates (k)

\

(a) e = 0.97 s”^; (b) k = 4.8 s"^;

(c) k = 9.5 s-i; (d) k = 13.5 s'M (e) k = 17 s’l;

(f) k = 19.2 s-i; (g) € = 24 s'l 31

6. Example of length change (dilation) vs. temperature during

continuous cooling and phase transformation of a steel specimen. 33

7. The detailed flow chart of the program for system control and

data acquisition 34

8. Computer command signals and the corresponding servohydraulic

stroke responses at a strain rate of 10 s~^ 35

9. The flow diagram of the post- test analysis program 36’

10. Pictures of the specimen used in the direct- quenching simulation

study; before and after deformation. 37

11. Results of double -deformation test on ASTM A710 steel.

(a) no softening in the second compression indicating no

recrystailization occurred; (b) softening in the second compression

indicating some degree of recrystailization occurred 38

12. Microstructures of ASTM A710 steel specimens with different

thermomechanical treatments; (a) and (b)

:

reaustenitized at

910°C then cooled slowly and gas quenched, respectively, without

deformation; (c) through (e)

:

treatments a through c described

in table 1. Etch: 3% nital 39

13. Continuous -cooling- transformation (CCT) diagram for

ASTM A710 steel; from Ref. 23. 40

14. Schematic illustration of increasing acicular ferrite

(granular bainite) hardenability by shifting the

polygonal ferrite nose to the right (shaded area)

.

41

15. Variation of microstructures from (a) near the surface and

(b) at the middle of the CR-DQ specimen. 42

V
16 . True o-e curves obtained in simulated CR-DQ experiments

(see table 1); (a) treatment a in Table 1; (b) treatment c in

table 1 . 43

17. Correlation of yield strengths in tension and yield strengths in

compression. Results of tension and compression at one strength

level were obtained from the same steel plate. 44

18. Correlation of tensile strengths with Knoop hardness numbers

(numerical data taken from Ref. 27). 45

19. The CCT diagram of microalloyed 1522 forging steel 46

20. Microstructures of 1522 microalloyed steel; (a) martensite after

fast cooling; (b) bainite after slow cooling 47

21. Determination of phase- transformation temperatures using

the seven-point incremental polynomial technique.

Bg ; bainite starts; Bf: bainite finishes; Mg : martensite starts;

Mf: martensite finishes. 48

22. True o-e characteristic of 1522 microalloyed steel at 1093°C

with a compressive strain rate of 10 s' ^ 49

23. The CCT diagram of the 1141 microalloyed forging steel.

Dashed line is the typical cooling rate found in a forging

without forced cooling (Ref. 31) 50

24. Microstructures of the microalloyed 1141 steel with

different cooling rates, (a) ferrite plus pearlite;

(b) pearlite-ferrite (Widmanstatten) plus small portion of bainite;

(c) bainite plus small portion of martensite;

(d) martensite plus small portion of bainite 51

vi
DEVELOPMENT OF A COMPUTER -CONTROLLED

HOT -DEFORMATION APPARATUS AT NIST

Yi-Wen Cheng

Yair Rosenthal*

Harry I . McHenry

Materials Reliability Division

National Institute of Standards and Technology

Boulder, CO 80303

This report describes a computer-controlled hot-deformation apparatus

suitable for thermomechanical-processing (TMP) simulation of forging and steel

plates. The apparatus was designed and built at the National Institute of

Standards and Technology, and has the following main features: a

servohydraulic load frame with a 250 kN capacity in tension or compression; a

variable - actuator traveling speed up to 55 mm-s'^; a multiple - strike

capability with controllable displacements and strain rates; a maximum heating

rate of 150®C-s"^ with a 10 kW induction heater (for a cylindrical steel

specimen 9 mm in diameter and 18 mm in height) ; a maximum cooling rate of

25°C*s“^ with helium-gas cooling; and vacuum to 1.33 x 10"^ Pa (1 x 10'^ Torr)

within 25 min. Source codes of the computer programs that perform system

control, data acquisition, and data analysis are included in this report. The

apparatus has been used to perform the direct-quenching simulation of the ASTM

A710 plate steel, and forging simulation of the directly cooled microalloyed

AISI 1522 and 1141 steels. Results of these studies are presented.

Key words; computer control; continuous-cooling transformation; controlled

rolling; direct quenching; forging; high-strength low-alloy steels; hotdeformation apparatus; microalloyed steels; physical simulation;

thermomechanical processing.

* Guest worker, on leave from Nuclear Research Center-Negev, Beer

Sheva, Israel.

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I. INTRODUCTION

Over the last twenty years, one of the most significant advances in the

steel industry has been the development and production of thermomechanical ly

processed (TMP) high-strength low-alloy (HSIA) steel plates, which offer an

excellent combination of strength, toughness, and weldability. Production

schedules for TMP plates require careful control over each step including slab

reheating, number of rolling passes, deformation and temperature for each

pass, and cooling conditions throughout rolling. Numerous experiments are

required to optimize these parameters for a new process or a new alloy system.

Experiments in a pilot- scale rolling mill, as has been typically done in the

past, are time consuming and costly, and measurements of rolling parameters

are sometimes difficult. As a result, several small-scale laboratory

simulation techniques, such as cam plastometry [1], torsion [2], and planestrain [3] or axisymmetrical [4] hot compression have been developed to

alleviate the problem. Small-scale laboratory simulations offer the obvious

advantages of economy, versatility, and reproducibility.

Small-scale laboratory apparatuses have been used for the following

studies

:

. To study the static recrystallization of austenite between intervals of

hot working [5]

;

To estimate the hot-deformation strength of austenite during controlled

rolling in a plate mill [6]

;

To study dynamic recrystallization [7]

;

To determine the nonrecrystallization temperature of austenite in

microalloyed steels [8]

;

. To simulate the direct quenching after controlled rolling of a HSIA

steel [9] .

In the past, the laboratory- scale apparatuses have been mainly applied to

study plate steels. Such apparatuses, however, are also being used to study

microalloyed steel wire [10] and seamless steel tube [11]. With the increased

use of directly cooled forging steels, the apparatus can be used as an

instrumented forging press for detailed study of these steels. This report

1
describes the development, at the National Institute of Standards and

Technology (NIST), of a hot -deformation apparatus, which is suitable for TMP

simulation of steel plates and forging. Examples of studies which have been

done using the apparatus are presented.

2
II. DESCRIPTION OF THE HOT -DEFORMATION APPARATUS

The actual operations of a rolling mill for plate rolling and of a

forging shop are very complex. The apparatus developed and described here is

by no means capable of duplicating the actual operations. Instead, the

apparatus has been designed only to simulate the idealized thermal and

mechanical treatments a metal (in the present case, a steel) receives during a

rolling or forging operation. The TMP sequences can be simplified and

depicted as those shown in figure 1 . The important parameters in TMP

simulations include the reheating rate, the soaking temperature and time, the

compression temperature (T)

,

the time interval (At) between compressions, the

amount of strain (e) in each compression, and the strain rate (e)

.

The

apparatus to be described here has the versatility to simulate a wide range of

TMP sequences typically encountered in plate rolling or forging.

The hot-deformation apparatus is shown in figure 2 and the interconnection among various components of the apparatus is given in figure 3

.

The apparatus can be loosely broken down and described by individual

components according to their functions: loading system, heating and control

system, cooling and control system, vacuum system, assembly for dilation

measurement after deformation, computer and peripherals, and computer programs

for system control, data acquisition, and data analysis.

Loading System; The load frame is a servohydraulic machine with a load

capacity of 250 kN. The machine has been upgraded in terms of actuator travel

speed. The upgrade includes the installation of a 5.7 x 10"^ m^-s"^ servovalve with a 3.8 X 10"^ m^ pilot manifold, which is set up for a 9.5 x 10”^ m^

accumulator mounted on the pressure side and a 1.9 x 10"^ m® accumulator on

the return side. This enables actuator control at speeds up to 500 mm-s"^,

which is adequate for plate-rolling or forging simulations.

The design of the load train is detailed in figure 4. Taking the

specimen as a cutoff line, we can treat the vertical load train as two

separate portions. The top portion is the hydraulic actuator, which contains

a loading ram (steel)

,

a suspended piston (Ti alloy) , a plug (Ti alloy) , and a

quartz platen. The upper end of the loading ram is connected to a load cell

3
and the hydraulic system, which controls the movement of the loading ram. The

bottom of the loading ram is connected to the Ti piston with a spring. The

separation of the top portion of the load train into a loading ram and a

piston facilitates the measurement of the length change of a steel specimen

during cooling and phase transformation. The measurement will be further

discussed later in this report.

The use of fused quartz as a loading platen at elevated temperature was

suggested by Ouchi [12] and has been proved to be satisfactory. Silicon

nitride has also been used for the same purpose [13] . The advantages of fused

quartz are low thermal conductivity, low thermal expansion coefficient,

relatively high strength and toughness at elevated temperatures, ease of

machining, and low cost. To ensure smooth surfaces, the contact surface of

the platens are polished with 1 /im diamond powder before an experiment. The

quartz platen is glued (with high- temperature epoxy) and physically clamped

onto the Ti plug, which is in turn threaded into the piston. The bottom

portion of the load train is stationary and contains the specimen. The load

train is rigid and well aligned. The maximum diameter of a cylindrical steel

specimen to be tested at 800°C is about 10 mm. Larger specimens often break

the quartz platen during compression. This limits the load that can be

applied to the platen to about 50 kN.

The most desirable deformation mode for plate-rolling or forging

simulations is a constant true-strain-rate compression, which not only closely

simulates the actual plate rolling but also eases data analysis and

interpretation. The constant true-strain-rate compression is accomplished

through interactive control of the load train by a personal computer (PC)

using the equation

H(t) = H(0) exp[-te] (1)

Here H(t) is the specimen's instantaneous height at time t, H(0) is the

initial height, and e is the desired constant true strain rate. Equation (1)

is derived from the total strain equation with a constant e

:

€ = ^n[H(0)/H(t) ] = €t ( 2 )

4
The implementation of eq (1) using a PC and its peripherals will be described

later in this report.

Theoretically, there is no limit to the value of e that can be used

according to eq (1). In practice, however, there are limitations on the value

of € that can be obtained in an experiment. The limitations are not with the

throughput of a PC or its peripherals; that is, the computation of eq (1) and

the rate of digital- to-analog conversion, but with the responses of a

servohydraulic system to its commands. Figure 5 shows examples of the

responses of the servohydraulic actuator in the current apparatus to various e inputs. Ideally, the time -vs . -total true strain relation is a linear line,

which is evident in the cases of e equal to 0.97 s‘^ (fig. 5a) and

4.8 s"^ (fig. 5b). However, at higher e, the actuator responds too slowly at

the beginning, then too fast, and finally overshoots at the end of the stroke

movement. This phenomenon has been observed at e > 9.5 s'^, particularly

those of 19.2 s"^ (fig. 5f) and 24 s"^ (fig. 5g)

.

Going too slowly at the beginning, then too fast, and finally

overshooting at the end is typical of and inherent in the servohydraulic

system at high e. To overcome the problem in a compressive experiment, we

retract the actuator at the beginning of a test so that the specimen is

compressed using only the lower half of the total true strain. Then, the

value of e is calculated using the actual signal from actuator responses, such

as those shown in figure 5.

Heating and Control System: Major components of the system are a 10 -kW, 450-

kHz induction generator (rf frequency) and a programmable temperature

controller. The heating is provided by the generator and controlled by the

temperature controller, which has ramp-and-soak and multiple-set-point

capabilities. Temperature is monitored with a type-S thermocouple (Pt-10%Rh)

welded directly onto the specimen. Thermal cycles in an experiment are

preprogrammed into the controller. The heating coil is a 4 . 76-mm-diameter Cu

tube. The ON/OFF switch of the generator is connected to a PC through a relay

for the ON/OFF control, which is important for a controlled cooling

experiment

.

5
Cooling and Control System: Cooling of a specimen is controlled with a PC by

regulating gas flow onto the specimen through a 6 . 35-mm-diameter Cu coil

concentric with the heating coil. The side of the cooling coil facing the

specimen is perforated to provide a gas flow that cools the specimen

uniformly. Either helium or nitrogen gas is used for cooling. Because of its

higher specific heat (5230 vs. 1030 J-kg'^-K"^ at 25°C) and greater mobility,

helium gas is more efficient than nitrogen in rapid cooling. For a

cylindrical steel specimen 10 mm in diameter by 18 mm in height, the cooling

rate is controllable to a maximum rate of 25®C-s"^.

In the initial design for cooling control, a process controller was used

to control the gas flow rate. After a few trials, we found that the time

needed for the process controller to interact with a flow-rate meter, and then

to control a gas regulating valve was too long. Therefore, the controlling

function of the process controller could not be properly realized. The

current practice has been to use a PC to open the gas regulating valve at a

predetermined value. Cooling rates were calibrated from experiments with

various settings in the gas regulating valve. To date, the system can set

only one flow rate for one experiment. This means that the system cannot

perform constant cooling- rate experiments because cooling is faster at higher

temperatures than at lower temperatures due to larger thermal differentials

between a specimen and its surrounding (constant ambient temperature) at

higher temperatures. This cooling profile, however, closely resembles that of

forging parts which are force -cooled while being transported through a

conveyer

.

Vacuum System : A vacuum is provided mainly to prevent specimen oxidation at

high temperatures. The vacuum also provides additional stability in

temperature control. The vacuum system consists of a stainless -steel chamber,

and a 100-mm diffusion pump with associated equipment such as a mechanical

pump, pressure gages, and a valve controller. The system can achieve a vacuum

of 1.33 X 10"^ Pa (1 X 10"^ Torr) within 25 min. The chamber is 381 mm long,

381 mm wide, and 432 mm high, and is made of a 9.5-mm-thick stainless-steel

plate. The bottom of the chamber is fastened to a stationary steel plate (see

figs. 2 and 4). The outside of the chamber is reinforced with welded

6
stainless-steel webs to provide rigidity, which is essential for precision in

dilation measurements.

View ports and various feedthroughs, such as those for instrumentations,

thermocouples, rf frequency power, and liquids, were provided with the

chamber. 0- rings were used to seal the top and bottom portions of the load

train. It should be mentioned here that at a pressure of about 1.33 x 10"^ Pa

(10"^ Torr) , gases will be ionized between the specimen and the heating coils.

At this pressure, it is impossible to heat the specimen because the rf field

arcs and shuts off the rf generator.

Assembly for Dilation Measurement After Deformation; The temperature and time

at which the transformation of austenite occurs during continuous cooling

plays an important role in determining the microstructure and, therefore, the

properties of a steel. A knowledge of transformation temperature and time can

be valuable in understanding the effects of composition, processing, and

cooling rate on the microstructure and properties, and can thus aid the

development of new and improved steels.

The methods available [14] to determine transformation and time include

thermal analyses, metallographic techniques, electrical-resistivity

measurements, magnetic-properties measurements. X-ray diffraction analyses,

and dilatometry. Among these methods, thermal analyses and dilatometry are

the most commonly used techniques for the detection of austenite

transformation during continuous cooling. For the application described in

this report, our experience shows that dilatometric measurements give more

definite and precise transformation temperatures than thermal analyses. In

this section, a dilatometric -measurement device capable of detecting the

decomposition of austenite in steels cooled directly from the finish

deformation operation is described.

The principles of dilatometry are associated with the dimensional changes

accompanying the decomposition of austenite. An acceleration or reversal of

dimensional changes during cooling indicates the occurrence of a solid-tosolid phase transformation, which may be correlated subsequently with the

temperature and time at which it occurs.

7
As noted in the Loading System section, to facilitate the measurement of

length change of a steel specimen during cooling and phase transformation, the

top portion of the load train was separated into a loading ram and a piston,

which were connected by a spring (fig. 4). In an experiment, the loading ram.

is retracted after the end of a compressive deformation so that a gap of

approximately 5 mm is maintained between the loading ram and the piston. This

leaves a force of about 40 N resting on the specimen during dilatometric

measurements. The force, which is required to maintain a constant contact

between the upper platen and the specimen, includes the spring loading plus

the weights of the piston, the plug, and the quartz platen.

Any changes in specimen's length during cooling and phase transformation

will result in axial movements of the piston, which are monitored by a

displacement gage. In order for the displacement gage to monitor the piston

movement, the displacement gage has to be placed before an experiment, at the

precise position at which the bottom end of the piston is anticipated to rest

after the end of a compressive deformation. The displacement gage has a

resolution of 0.9 fim and a travel range of 3.5 mm. From the measured length

change -vs .- temperature data, such as that shown in figure 6, phasetransformation temperatures are determined using statistical techniques.

Computer and Peripherals; The computer used is a 20-MHz 80386 personal

computer, equipped with a board- level analog- to -digital (A/D) plug-in board

having a 45 -kHz throughput and with an IEEE GPIB board. The A/D board

contains eight differential A/D channels (for input) and two digital -to

analog (D/A) channels (for output) . The peripherals of the computer include a

20-MHz 80387 math coprocessor, a line printer, a 60-MByte hard disk, a

1.2 -MByte floppy disk drive, and a 360-kByte floppy disk drive.

The hot -deformation apparatus is also equipped with a programmable

digital storage oscilloscope and a programmable waveform generator. The

oscilloscope includes four 15-bit 100-kHz digitizers and is used for highspeed data acquisition (each channel can store up to 4000 data points when all

four channels are operating simultaneously) ; the waveform generator is used to

provide 5 V for opening a gas valve in controlled cooling experiments.

8
Computer Programs for System Control. Data Acquisition, and Data Analysis;

Computer programs were written in a scientific, stack-oriented, incrementaliy

compiled programming language [15,16]. Two programs, (1) System Control and

Data Acquisition program, and (2) Data Analysis and Summarizing Report

Production program, were written to perform system control, data acquisition,

and post-test data analysis. The source codes of the computer programs are

attached in Appendixes 1 and 2

.

The program for system control dictates the sequence of operations of the

various components of the hot-deformation apparatus. A detailed flow chart of

the System Control and Data Acquisition program is given in figure 7. With

reference to the figure, the thermal cycle from heat-to-soak temperature to

the last compression is controlled by an autonomous programmable temperature

controller, as described in the section on Heating and Control System. During

an experiment, the computer continuously reads the thermocouple signals

through an A/D channel, because temperatures determine when a compression is

to take place. (Alternatively, time can be used as the controlling

parameter) . As soon as the predetermined testing temperature is reached, the

computer triggers the oscilloscope for data acquisition through the GPIB bus

and then sends a string of signals through a D/A channel for controlling the

movement of the stroke, which performs the actual compression. The same

sequence is repeated until the completion of the last compression; then the

computer commands the oscilloscope for transferring the data onto floppy

disks, turns off the induction heating generator, and opens a pneumatic valve

for controlled cooling. To turn off the induction-heating generator, the

computer sends a 5-V signal, through a programmable waveform generator on the

GPIB bus, to break the heating circuit.

In an experiment, a compression is specified by the original height,

H(0)

,

and the final height, H(f)

,

of the specimen and by the deformation mode,

such as constant e. For a constant e compression, the total true strain is

e = ^n[H(0)/H(f)] = ett (3)

and the total compression time, t^, is

9
= e/k = in[H(0)/H(f)]/€ (4)

Using eqs (1) and (4), the computer computes a string of exponentially

decreasing numbers, which are converted to voltages and calibrated to

represent displacement in millimeters, and sends the numbers to the stroke

controller through a D/A channel. Figure 8 shows a typical output of the D/A

channel and the stroke response of the hydraulic testing machine. With

reference to the computer output signals, the stroke response has a delay and

a small overshoot at the end of the curve. These are due to the inherent

characteristics of the servohydraulic system at high e . The response delay

and the overshoot diminish at lower e

.

Because of the discrete nature of digital signals, such as the inputs to

the D/A channel from the computer, it is desirable to have as many points as

possible for a compression test in order to obtain a continuous, smooth output

from the D/A channel. However, the number of data points that can be used in

a compression test is limited by the computation time needed by the computer

and the execution time needed by the D/A channel. For the present computer

system at a e of 15 s"^, the maximum number of data points that can be

processed while maintaining a satisfactory result is about 200. This number

of data points can be used with e as low as 1 s' At lower e, more points

are required to maintain a continuous, smooth signal.

The communication between the PC and the various devices is through eight

A/D channels, two D/A channels, and the IEEE GPIB bus. The desired direct

measurements from an experiment typically include load, stroke movement,

temperature, and the specimen's length change with respect to temperature.

The apparatus was originally designed to use three of the eight A/D channels

to acquire these measurements. After a few trials, we found that

simultaneously one PC alone could not satisfactorily control the stroke

movement through one D/A channel and acquire the data of load, stroke

movement, and temperature through three A/D channels. When one PC performs

these functions simultaneously, a maximiom of only 50 data points can be

executed for stroke control at a e of 10 s' this produces discontinuous

signals with discrete steps. The problem lies in the fact that after the

10
computer sends one stroke -controlling signal through a D/A channel, it has to

open three A/D channels to receive data of load, stroke movement, and

temperature. The time needed to complete a set of this sequence is too long

to be satisfactory.

Therefore, in high k experiments the functions of stroke control and data

acquisition must be performed by separate, autonomous devices. This can be

done with a second PC equipped with high-speed A/D boards or other dataacquisition devices. In the present apparatus, we used a programmable digital

storage oscilloscope, which equips with two floppy-disk drives for instant

data storage. For a multiple-strike experiment, the signals of load, stroke

movement, and temperature are captured with the oscilloscope and saved onto

the floppy disks. This sequence is repeated for every compression. The time

required for saving the signals from the oscilloscope onto the floppy disks is

about 6 s, which is the minimum time required between two consecutive

compressions

.

Because of the high-speed nature of a plate-rolling or forging simulation

(one compression is typically completed within 0.1 s) , synchronization of the

stroke-control subprogram and the data-acquisition subprogram is crucial.

Without proper timing in triggering the oscilloscope for data acquisition and

storage, the information needed from an experiment would be lost. The

synchronization is complicated by the different command execution times

required by different devices. In our case, the time required to activate the

stroke -control sequence through the D/A channel is much shorter than that

required to trigger the oscilloscope through the GPIB bus. Thus, the

activation of the stroke-control sequence must be delayed after the triggering

commands have been sent to the oscilloscope. The optimum delay times between

different devices were obtained by trial and error.

The raw data saved on the oscilloscope's disks are load vs. time, stroke

movement vs. time, temperature vs. time, and the specimen's length change vs.

time. These data on floppy disks can not be retrieved directly by a PC

because of differences in disk formats. A specially programmed digitalprocessing software [17] must be used to enable the PC to read the data from

the disks. Depending on the purpose of a simulation experiment, the program

11
for post- test analysis can calculate the various material properties from

load- vs stroke movement data. The properties include Young's modulus,

proportional limit, yield strength, engineering a-e curve, true a-e curve, and

strain-hardening characteristics. From the specimen's length change-vs.-

temperature data, the program can produce dilation-vs . -temperature

curves (fig. 6) , from which continuous -cooling transformation (CCT) diagrams

can be generated. The operation of the analysis program is interactive and is

summarized in figure 9.

12
III. EXAMPLES OF USING THE APPARATUS

The hot-deformation apparatus described in the previous section is being

used to perform the following studies: the direct- quenching simulation of

ASTM A710 steel, and forging simulation of the directly cooled microalloyed

AISI 1522MV and 1141 forging steels.

Direct-Quenching Simulation of ASTM A710 Steel : Controlled rolling followed

by direct quenching (CR-DQ) eliminates the reaustenitizing-and-quenching step

required in the conventional quenched- and- tempered (Q-T) heat treatment; thus,

it saves energy and reduces manufacturing costs. The CR-DQ process also

increases strength and improves the notch toughness of microalloyed steels,

when compared to the conventional rolling and direct -quenching process [18].

The conventional process of producing Q-T steel plates is summarized as

follows

:

1. A slab is reheated to and held at a reheating temperature for a

predetermined soaking time.

2. The slab is subjected to several passes of rough rolling.

3. The slab then receives several passes of finish rolling to become a

finished plate.

4. The plate is air-cooled to ambient temperature.

5. The plate is reheated to an austenitizing temperature for a predetermined

length of time.

6. The plate is quenched and then tempered.

In a CR-DQ process, the slab reheating temperature is lower than that of

conventional processes. Step 3 is done at temperatures below the austenite

recrystallization temperature. Step 3 is followed by step 6; thus, steps 4

and 5 are eliminated. The objective of the study is to understand the general

response of the ASTM A710 steel to the CR-DQ treatments.

13
Material : The material used for this simulation study was a copper precipitation-strengthened steel: ASTM designation A710 [19]. The chemical

composition of the steel in weight percent is

C Mn S Si P Nb V Ni Cr Mo Cu

0.03 0.54 0.002 0.33 0.009 0.052 0.005 0.96 0.93 0.217 1.04

The steel was received in a 19 -mm—thick plate form and was conventionally

processed, that is, hot—rolled to a thickness of 19 mm, air-cooled,

reaustenitized, quenched, and aged. Cylindrical specimens, 10 mm in diameter

by 18 mm in height, were taken from the plate; the cylindrical axis coincided

with the long transverse direction. A specimen before and after deformation

is shown in figure 10.

Experimental Details : In this study, the sequence of CR-DQ was simplified and

simulated by two compressions. The simplified temperature -deformation

sequences are described in table 1. The first compression simulates the rough

rolling and the second compression represents a heavy reduction in the

nonrecrystallized austenite region. All specimens were quenched with gas

(either helium or nitrogen) immediately after the second compression.

The selection of 900 and 850°C for the second compression, as described

in table 1, was based on the results obtained using a double -deformation

test [5,8]. As shown in figure 11a, there is no softening in the second

compression, indicating no recrystallization at 950°C. Softening is observed

in figure lib, which shows the results tested at 1000°C. Based on figure 11,

we conclude that recrystallization occurred between 950 and lOOO^C.

Results and Discussion : Figure 12 shows the microstructures and diamondpyramid microhardness (DPH) measurements of different thermomechanical ly

treated specimens in the as—cooled condition (without aging) . Figures 12a and

12b are microstructures of specimens reheated to 910®C, held for 10 min, and

then cooled slowly in vacuum with heater power off (fig. 12a) and helium—gas

quenching (fig. 12b), respectively. These specimens were not deformed.

14
Table 1. Temperature-deformation sequences for simplified CR-DQ simulations.

^reheat temperature: 1150°C for 5 min followed by slow cooling at a rate

between 0.5 and l.l°C-s’^

*first compression: 30% reduction at 1050°C

second compression:

treatment (a)

:

30% reduction at 900°C followed by helium—gas

quenching at a rate of 16°C*s'^ between 800 and 500°C

treatment (b)

:

30% reduction at 850°C followed by helium—gas

quenching at a rate of 17C-s"^ between 800 and 500°C

treatment (c)

:

40% reduction at 850C followed by nitrogen—gas quenching

at a rate of 9°C-s"^ between 800 and 500°C

*applied to all CR-DQ specimens

Figures 12c through 12e are microstructures of specimens with treatments (a)

through (c)

,

respectively, as described in table 1. The corresponding DPH

numbers are also given along with each microstructure at the upper left corner

of each micrograph in figure 12.

Three distinct microstructural features are shown in figure 12.

Figure 12a shows that the main constituent is the equiaxed polygonal ferrite

(white areas) with randomly dispersed second—phase patches (dark areas)

,

which

are thought to be a mixture of pearlite, bainite, and martensite. With

increasing cooling rate, a portion of the polygonal ferrite becomes acicular

in shape, as shown in figure 12b; the predominant feature is still polygonal

ferrite. With the simplified CR-DQ processing, the predominant

microstructural features of some specimens change drastically from polygonal

ferrite to granular bainite (acicular ferrite) [20], as shown in figures 12c,

12d, and 12e. The second—phase islands in these microstructures (figs. 12c,

12d, and 12e) are thought to be a mixture of retained austenite and

martensite [21,22]. The changes in microstructures are also reflected in the

DPH measurements as indicated in figure 12.

We considered two ways to explain the change in microstructure from

polygonal ferrite as shown in figures 12a and 12b to granular bainite as shown

in figures 12c, 12d, and 12e. First, we considered the higher cooling rates;

15
that is, the polygonal ferrite nose was missed during cooling and granular

bainite was obtained. According to the continuous—cooling transformation

(CCT) diagram, as shown in figure 13, for the ASTM A710 steel [23], it is

necessary to cool the steel from 800 to 500°C in less than 1 or 2 s in order

to obtain a predominantly granular bainite microstructure. However, in the

present investigation, it took from 18 [treatment (b)

]

to 35 s [treatment (c)j

to cool from 800 to 500*^0. Therefore, these cooling rates were not expected

to cause the observed drastic change in microstructure.

Second, we considered the increased (bainitic) hardenability of the steel

due to the simulated CR-DQ process. This means that the polygonal ferrite

nose in the CCT diagram is shifted to the right, as schematically shown in

figure 14, and granular bainite forms at slower cooling rates. This best

explains the observed microstructures. But what are the mechanisms that cause

the hardenability to increase? Deformed, unrecrystallized austenite, as a

result of controlled rolling, has been shown to decrease the hardenability of

various steels [24,25]; this is contrary to what we observe here.

Hardenability is increased by an increase in austenite grain sizes before

transformation [26]

.

After soaking at 1150°C for 5 min, the austenite grain

sizes were about 40 //m in the present study, compared with 10 /zm for the CCT

diagram [23]. The other probable cause of increased hardenability is a larger

amount of alloying elements dissolved in the austenite before transformation;

this reduces the rates of ferrite nucleation and growth. The alloying

elements come from more dissolution of carbides and/or carbonitrides at the

soaking temperature of 1150°C. The dissolution of alloy carbides or

carbonitrides is not possible in a conventional Q-T treatment with the

austenitizing temperature of 900°C.

The microstructures shown in figure 12 were taken from the middle of the

specimens. The microstructures of the specimens without compression

(figs. 12a and 12b) are uniform throughout the specimen. For the simulated

CR-DQ-processed specimens, the microstructure varies from the surface to the

middle of the specimen, as shown in figure 15. The variation of microstructure within a specimen is directly related to nonuniform deformation in

cylindrical compression due to barreling. The total strain and the strain

16
rate reach maxima at the middle of the specimen. They reach minima at points

just beneath the contact surfaces; this area is called the "dead zone." The

observed microstructures correlate well with this strain—pattern analysis:

large strains at the middle of the specimen resulted in small and "pancaked"

austenite grains, as shown in figure 15b; small strains near the surface

resulted in large and equiaxed austenite grains, as shown in figure 15a. In

light of this observation, we should be cautious in interpreting results

obtained from a small-scale simulation.

The true a-vs.-e characteristics of each compression during the CR-DQ

simulations are shown in figure 16. The initial flow stress for the second

compression is considerably lower than the final flow stress during the first

compression, which shows a strong indication that the austenite was already

fully recrystallized before the second compression (by considering the true ovs . - € characteristics of the second compressions). Figure 16 also shows a

strong influence of temperature on true a-e curves.

The size of a sample after TMP processing with the hot-deformation

apparatus is about 20 mm in diameter and 10 mm in height. This size is

insufficient for machining a standard tension- test specimen. Therefore, the

tensile strengths cannot be measured directly and must be inferred from other

types of measurements. In the present study, using specimens taken from the

same steel plates, we showed that there are good correlations between

(1) yield strengths in tension and yield strengths in compression (fig. 17),

and (2) tensile strengths and Knoop hardness numbers (fig. 18)

.

Studies of Directly Cooled Forging Steels : The directly cooled microalloyed

(MA) forging steels have been introduced to the automotive industry as

economical substitutions for some quenched- and- tempered (Q-T) grades. These

MA steels can achieve tensile strengths comparable to those of Q-T steels, but

with lower impact properties. Research to improve the toughness of directly

cooled MA steels is increasing. Several approaches to raise the toughness

while lowering the ductile- to-brittle transition temperature have been cited

in the literature [28,29,30]. These include: (1) lowering the carbon content

from 0.5% to 0.35 or 0.25%; (2) lowering the reheating temperature and the

finish- forging temperature to control the austenite grain size; (3) adding Ti

17
(to produce TiN particles) to control austenite grain size; (4) modifying the

steel chemistry, such as increasing Mn or Si content; (5) controlling MnS

inclusions to increase intragranular ferrite nucleation; and (6) producing

low-carbon bainitic steels.

Our study is to provide metallurgical data measured during simulated

forging processes so as to optimize forging design and forging procedures.

The data will include the true a-e characteristics of MA steels at high

temperature under high e

,

CCT diagrams determined under different forging

parameters (reheating temperature, finish- forging temperature, deformation

rate), microstructure, and hardness characterization. This is an ongoing

research, and this report presents the preliminary results obtained to date.

Materials : The materials used in this study are two MA steels: AISI 1141, a

ferritic-pearlitic steel, and AISI 1522, a bainitic steel. The steels were

supplied as 25.4-mm (1141) and 31 . 75-mm-diameter (1522) round bars in the asrolled condition, produced from continuous casters. The chemical compositions

in weight percent are

C Mn P S Si Cu Ni Cr Mo V Nb Sn A1

1141 0.42 1.49 0.015 0.099 0.26 0.16 0.06 0.06 0.009 0.039 0.006

1522 0.24 1.67 0.014 0.028 0.39 0.42 0.14 0.17 0.22 0.11 --- 0.013 0.006

Experimental Details : Cylindrical specimens, 9 mm in diameter by 18 mm in

height, were taken from the bars. For 1522 steel, specimens were reheated to

1093°C and held for 10 min. Specimens were then cooled to ambient temperature

with different cooling rates using forced helium gas for establishment of a

CCT diagram. To investigate the effects of deformation on the CCT diagram and

final microstructure, a series of specimens were heated to 1260°C and held for

5 min. Specimens were then cooled to 1093°C, at a rate of about l°C-s"^. At

1093°C, the specimens were compressed 50% with a e of 10 s"^. Following the

compression, the specimens were cooled to ambient temperature with different

cooling rates to establish the CCT diagram. This experiment also produced

true a-e curves at 1093°C under e of 10 s"^. To date two specimens have been

18
tested with these treatments. This series of experiments is continuing, and

plans include experiments with different combinations of reheating

temperature, deformation temperature, and e.

For 1141 steel, specimens were reheated to 1218°C, and held for 5 min.

Specimens were then cooled to ambient temperature with different cooling rates

using forced helium gas to establish a CCT diagram. Future plans for this

steel are the same as those for 1522 steel, that is, we will study the effects

of different combinations of reheating temperature, deformation temperature,

and e .

For both steels, selected specimens processed with different processing

parameters will be characterized and evaluated using optical metallography or

electron microscopes, if necessary, and a microhardness tester.

Results and Discussion : 1522 Steel : Results obtained to date include the CCT diagram with specimens

under heating and cooling (no deformation) , microstructure of selected

specimens, and true a-e curves at lOQS^^C with a e of 10 s'^. The CCT diagram

is shown in figure 19. The far-right cooling curve in figure 19 is comparable

to that of a 25 -mm- diameter round bar transported on a conveyer. This cooling

rate is typical of an automotive component (with the same size) transported on

a conveyer after forging without forced cooling. The microstructure produced

at this cooling rate is predominantly bainite, as shown in figure 19. This is

confirmed by the light micrograph presented in figure 20b. Figure 20a shows

the martensite produced after fast cooling, corresponding to the far- left

curve in figure 19.

The temperatures at which phase transformation occurs can be best

determined by dilatometric measurements. Figure 6 shows that the

determination of phase- transformation temperature is not straightforward. In

order to minimize the human factors in determining the phase- transformation

temperatures, we use statistical techniques to analyze the dilation-vs .

temperature data, such as that shown in figure 6. First, we performed the

direct derivation on dilation-vs .- temperature data. The results produced too

much scatter to give definite phase- transformation temperatures. Then, we

19
used the seven-point incremental polynomial technique to smooth the data; this

approach yielded results with less scatter. Representative curves obtained

from this analysis are given in figure 21.

Although the polynomial technique makes it easier and less ambiguous to

determine the phase- transformation temperatures, subjective judgement is still

needed. This is especially true in the case of the martensite -finish

temperature, Mf. This is clearly indicated in figure 21. The reason for the

difficulty in Mf determination (in this study) is that the temperature

difference between the Mf temperature and the ambient temperature is

relatively small, about 100 to 150°C. This produces a relatively short linear

portion in the derivative (dl/dT) of dilation with respect to temperature.

Any deviation (the Mf temperature) from the linear line becomes ambiguous and

is thus difficult to determine with certainty.

A true a-e curve is calculated from the load-vs . -stroke movement data

acquired during compression. A representative curve obtained at 1093°C with a

e of 10 s‘^ is given in figure 22.

1141 Steel : Using the same procedures described earlier, we produced a CCT

diagram of the MA 1141 steel as shown in figure 23. Also included in

figure 23 is the cooling profile (dashed line) typically found in a forging

without forced cooling [31]. This cooling profile is similar to that shown in

the far-right curve on figure 23. Selected microstructures corresponding to

different cooling rates are presented in figure 24. Figure 24a is a ferriticpearlitic microstructure produced with the slowest cooling rate in this

investigation. Martensite with a small fraction of bainite (fig. 24d) is

observed with the fastest cooling. Figures 24b and 24c represent the

microstructures obtained with intermediate cooling rates. Microstructure in

figure 24b is a mixture of pearlite with small areas of ferrite

(Widmanstatten) and bainite. Bainite plus martensite is the microstructure

observed in figure 24c.

20
IV. CONCLUSIONS AND SUMMARY

A computer- controlled laboratory- scale hot-deformation apparatus has been

designed and built at the National Institute of Standards and Technology

(NIST) . The use of this apparatus for studying thermomechanical processing of

metals has the obvious advantages of economy, versatility, and

reproducibility. In the past, the laboratory- scale apparatuses have been

mainly applied to study plate steels. With the increased use of directly

cooled forging steels, the apparatus described in this report can be used as

an instrumented forging press for detailed study of these steels.

The apparatus has the following main features: a servohydraulic load

frame with a 250 kN capacity in tension or compression; a variable -actuator

traveling speed up to 55 mm*s"^; a multiple-strike capability with

controllable displacements and strain rates; a maximum heating rate of

150°C’s"^ with a 10 kW induction heater (for a cylindrical steel specimen 9 mm

in diameter and 18 mm in height); a maximum cooling rate of 25°C*s“^ with

helium- gas cooling; and vacuum to 1.33 x 10"® Pa (1 x 10“^ Torr) within 25

min.

The apparatus has been used to simulate direct quenching of ASTM A710

steel and forging followed by direct cooling of microalloyed AISI 1522 and

1141 steels. For the A710 steel, the results indicated that bainitic

(granular) hardenability was greater with the controlled rolling followed by

direct quenching (CR-DQ) than with the conventional quenching- and- tempering

(Q-T) process. The positive implication of the observation is that the

strength of the steel can be increased with CR-DQ processing, or the amount of

alloying elements can be reduced while maintaining the same strength level.

For the MA 1522 and 1141 steels, CCT diagrams were determined from the

derivatives of the dilation-vs . -temperature data using the seven-point

incremental polynomial technique. Although the technique using the smoothed

derivatives helps to make the determination of phase- transformation

temperatures less ambiguous, subjective judgement is sometimes still needed,

especially in the case of martensite-finish temperature. Microconstituents,

such as ferrite, pearlite, bainite, and martensite, shown in the CCT diagrams

21
were confirmed with microstructures revealed by optical metallography. In

addition to producing CCT diagrams and microstructures of specimens cooled at

different rates, we will also conduct experiments in forging simulation to

develop the information needed for the optimization of forging processes. The

information includes high- temperature , high strain- rate flow characteristics

and the effects of reheating temperature and finish- forging temperature on the

CCT diagrams and final properties.

22
V. ACKNOWLEDGMENTS

The microalloyed AISI 1522 and 1141 steels were supplied by K. Grassl of

Chaparral Steel Company and J.H. Hoffmann of Chrysler Motors Corporation,

respectively. Special thanks are due to C. Ouchi of the NKK Corporation for

many helpful discussions on the simulation of thermomechanical processing.

Dr. S.W. Thompson of Colorado School of Mines is appreciated for helpful

discussion on metallography. Assistance from D.T. Lovering, J.D. McColskey,

and D.P. Vigliotti of NIST, and A. Cossa and M.C. Mataya of Rockwell

International during various stages of installation of the apparatus is

appreciated. The assistance of D.A. Shepherd and A. Tomer (on leave from

Nuclear Research Center, Israel) of NIST in performing optical metallography

and hardness measurements is also acknowledged.

23
VI. REFERENCES

[1] M. J. Steward, "Constant True Strain Rate Compression: The Cam

Plastometer , " Canadian Metallurgical Quarterly, Vol. 13, No. 3 (JulySept. 1974), pp. 503-509.

[2] H. Weiss, D. H. Skinner, and J. R. Everett, "A Torsion Machine for

Programmed Simulation of Hot Working," J. of Physics E: Scientific

Instruments, Vol. 6 (1973), pp . 709-714.

[3] 0. Pawelski and V. Gopinathan, "Comparison of Material Flow and

Deformation Resistance of HSLA Steel Deformed by Hot Rolling and Flat

Compression under Simulated Conditions," J. of Mechanical Working

Technology, Vol. 5 (1981), pp . 267-280.

[4] C. Ouchi and S. Yamamoto, "Development of Hot Deformation Equipment

'THERMECMASTER-Z' and Studies of Hot Deformation Behaviors of Steels,"

Technical Research Center, Nippon Kokan K. K. , Japan.

[5] R. A. P. Djaic and J. J. Jonas, "Static Recrystallization of Austenite

between Intervals of Hot Working," J. of the Iron and Steel Institute

(April 1972), pp. 256-261.

[6] C. Ouchi, T. Okita, T. Ichihara and Y. Ueno, "Hot Deformation Strength of

Austenite during Controlled Rolling in A Plate Mill," Trans, the Iron and

Steel Institute of Japan, Vol. 20 (1980), pp . 833-841.

[7] T. Sakai, M. G. Akben and J. J. Jonas, "Dynamic Recrystallization during

the Transient Deformation of a Vanadium Microalloyed Steel," Acta

Metall., Vol. 31, No. 4 (1983), pp . 631-642.

[8] Y. Z. Zheng, A. J. DeArdo , R. M. Fix and G. Fitzsimons, "Achieving Grain

Refinement through Recrystallization Controlled Rolling and Controlled

Cooling in V-Ti-N Microalloyed Steels," in HSLA Steels: Technology &

Applications, ASM, Metals Park, OH (1984), pp . 85-94.

[9] Y. W. Cheng and H. I. McHenry, "A Hot-Deformation Apparatus for

Thermomechanical Processing Simulation," in Proceedings of Inti. Symp. on

Physical Simulation of Welding, Hot Forming and Continuous Casting,

Ottawa, Ontario, Canada, May 2-4, 1988. (in press)

[10] K. Namiki , K. Isokawa and T. Kato, "Microalloyed Steel Wire for

Automotive Fasteners," in Fundamentals of Microalloying Forging Steels,

the Metallurgical Society, Inc., Warrendale, PA (1987), pp. 521-537.

[11] R. Barbosa, S. Yue , J. J. Jonas and P. J. Hunt, "Accelerated Cooling

Applied to the Recrystallization Controlled Rolling of Seamless Tubing,"

in the Proceedings of the Inti. Symp . on Accelerated Cooling of Rolled

Steel, Pergamon Press (1988), pp . 373-386.

24
[12] C. Ouchi, Technical Research Center, Nippon Kokan K. K. , Japan, private

communication

.

[13] M. C. Mataya, Rockwell International, Golden, CO., private communication.

[14] G. L. Kehl, The Principles of Metallogranhic Laboratory Practice. 3rd

edition, McGraw-Hill Book Company, Inc., 1949.

[15] ASYST Software Technologies, Inc., 100 Corporate Woods, Rochester, NY.

(Commercial systems are mentioned for identification only; no endorsement

is intended.)

[16] Y. Rosenthal and Y. W. Cheng, "Computerization of a Thermomechanicai

Processing Research System," J. of Intelligent Instruments and Computers,

March/April 1989.

[17] Vu-Point, S-Cubed: a Division of Maxwell Laboratories, Inc., P. 0. Box

1620, La Jolla, CA 92038. (Commercial systems are mentioned for

identification only; no endorsement is intended.)

[18] K. A. Taylor and S. S. Hansen, "Structure and Properties of Some

Directly—Quenched Martensitic Steels," in Accelerated Cooling of Rolled

Steel (Winnipeg), G. E. Ruddle and A. F. Crawley, eds . , Pergamon Press

(1988), pp. 85-101.

[19] Annual Book of ASTM Standards, Vol. 01.04, Section 1, American Society

for Testing and Materials, Philadelphia, PA (1987), pp . 664-667.

[20] L. J. Habraken and M. Economopoulos , "Bainitic Microstructures in

Low—Carbon Alloy Steels and Their Mechanical Properties," in Transformation and Hardenabiiity in Steels, Climax Molybdenum Co., Ann Arbor, MI

(1967), pp. 69-108.

[21] S. W. Thompson, Colorado School of Mines, Golden, Colorado; private

communication

.

[22] M. R. Krishnadev, "Development and Characterization of a New Family of

Copper—Containing HSLA Steel," in HSLA Steels: Technology & Applications

(Philadelphia), ASM, Metals Park, OH (1984), pp

.

129—147.

[23] G. R. Speich and T. M. Scoonover, "Continuous—Cooling—Transformation

Behavior and Strength of HSLA—80 (A710) Steel," in Proceedings of the

Inti. Symp . on Processing, Microstructure, and Properties of HSLA Steels

(Pittsburgh), A. J. DeArdo ed.

,

TMS-AIME, Warrendale, PA (1988), pp . 263-

286.

[24] R. Kaspar, A. Streisselberger , and 0. Pawelski, "Thermomechanicai Treatment of Ti— and Nb—Mo—Microalloyed Steels in Hot Strip Roiling," in

Thermomechanicai Processing of Microalloyed Austenite (Pittsburgh) , A.

J. DeArdo, G. A. Ratz

,

and P. J. Wray, eds., TMS-AIME, Warrendale, PA

(1982), pp. 555-574.

25
[25] C. M. Vlad, "The Effect of Cooling Rates on the Transformation Behavior

of Deformed Austenites," in Accelerated Cooling of Steel (Pittsburgh), P.

D. Southwick, ed. , TMS—AIME, Warrendale, PA (1986), pp . 435—446.

[26] G. Krauss, Principles of Heat Treatment of Steels, ASM, Metals Park, OH

(1980)

.

[27] G.E. Hicho, et. al, "Effect of Heat Treatment on Mechanical Properties

and Microstructure of Four Heats of ASTM A710 Steel," NBSIR 84-2891,

Gaithersburg, MD (1985).

[28] M. Korchynsky and J.R. Paules, "Microalloyed Forging Steels - A State of

the Art Review," International Congress and Exposition, February 27-March

3, 1989, Detroit, MI, Paper No. 89081.

[29] T. Ouchi, T. Takahashi , and H. Takada, "Improvement of the Toughness of

Hot Forged Products through Intragranular Ferrite Formation," Proceedings

of the 20th Mechanical Working and Steel Processing Conference, October

23-26, 1988, Dearborn, MI, pp. 65-72.

[30] K. Matysumoto, et. al., "Development of Low-Carbon Bainitic Bar Steel for

Hot Forged Use," ibid., pp . 73-81.

[31] J.H. Hoffmann, Chrysler Motors Corporation, Highland Park, MI, private

communication

.

26
Controlable

Parameters

3aniva3diAi3i

I

27

Figure

1

.

Thermal

and

mechanical

treatments

in

a

thermomechanical

processing

(TMP)

simulation.
LoadTf^in Lead and

Displacement Controller: Vacuum li

Chainlx^J

Induction

; Heater i

Vacuum, Gas Flow

and Temperature I Controllers —gfe

Figure 2. Hot- deformation apparatus. (a) overall view; (b) interior of

the vacuum chamber

.

28
Figure 3. The basic components of the hot-deformation apparatus.

29
steel Plate

4. Drawing of tVie load train and the device for measurenient of

length change during cooling and phase transformation.

30
w

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32

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5.

(continued)
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33

Figure

6.

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length

change

(dilation)

vs.

temperature

during

continuous

cooling

and

phase

transformation

of

a

steel
TEST TEMPERATURE? YES

TRIGGER

OSCILLOSCOPE 4- COMPUTER GPIB OUTPUT

SIGNAL TO OSCILLOSCOPE

1st COMPRESSION

no

LAST COMPRESSION?

yes

TRIGGER OSCILLOSCOPE — —

TURN OFF THE INDUCTION

HEATING GENERATOR

START COOLING TO

ROOM TEMPERATURE

ACQUIRE DATA FROM LOAD CELL

AND DISPLACEMENT GAGE

COMPUTER D/A

OUTPUT SIGNAL TO THE

STROKE CONTROLLER

SAVE LOAD AND

DISPLACEMENT DATA

COMPUTER GPIB OUTPUT

SIGNAL TO WAVEFORM

GENERATOR

D/A SIGNAL TO THE VALVE FOR

COOLING CONTROL

Figure 7

.

The detailed flow chart of the program for system control and

data acquisition.

34
30.0

-lO

I

I I I I

| -I I I I

I I I I I

I

i "

i-T'i-r I I I I I

I I I I

I

I I I I

I I I I I

I

I I I I |' ~ o

ID O in o in o in

in CM CD ID cvi CD

CM CM CM CM •*— r—

luiu ‘tuaiuaoeidsia

35

Figure

8.

Computer

command

signals

and

the

corresponding

servohydraulic

stroke

responses

at

a

strain

rate

of

10

s
Figure 9. The flow diagram of the post- test analysis program.

36
Figure 10. Pictures of the specimen used in the direct- quenching

simulation study; before and after deformation.

I

37
TRUE

STRESS.

MPa

ASTM A710 HSLA Steel

Reheated at 1150°C for 10 min

Soaked at 950°C for 10 min

Compressed Twice at 950®C

Time Between Compressions: 0.5 s

(a)

ASTM A710 HSLA Steel

Reheated at 1150°C for 10 nnn Soaked at 1000®C for 10 min

Compressed Twice at 1000°C

Time Between Compressions: 30 s

(b)

Figure 11. Results of double -deformation test on ASTM A710 steel.

(a) no softening in the second compression indicating no

recrystallization occurred; (b) softening in the second

compression indicating some degree of recrystallization

occurred.

38
Figure 12. Microstructures of ASTM A710

steel specimens with different

thermomechanical treatments;

(a) and (b) : reaustenitized at

910°C then cooled slowly and

gas quenched, respectively,

without deformation; (c)

through (e)

:

treatments a

through c described

in table 1. Etch: 3% nitai.

39
CONTINUOUS

COOLING

TRANSFORMATION

DIAGRAM

FOR

HSLA-80

do '3aniVU3dlAI31

o

o

(C

o

o

CM o

o

00

o

o o

o

o'

o

o

o

o

o

o

o

fO ®o s<

" 5

o

0)

CO

UJ

® i

o

d

Do '3dfUVa3dlAI31

40

Figure

13.

Continuous

-coolingtransformation

(CCT)

diagram

for

ASTM

A710

steel;

from

Ref.

23.
CONTINUOUS

COOLING

TRANSFORMATION

DIAGRAM

FOR

HSLA-80

STEEL

do ‘3aniva3di/M3i

41

Figure

14.

Schematic

illustration

of

increasing

acicular

ferrite

(granular

bainite)

hardenabiiity

by

shifting

the

polygonal

ferrite

nose

to

the

right

(shaded

area).
>. Av-S- ; I '•£

S H ^ >e^ > ^ V.S vvA \ K «**ns'**^% O

E

:l

o

ndC

cd

(U- O

cd

(+-I

^-1 :dM

a; X4Ju

cd

0)C

cd

C

0)S

•r-l

E

o

<4-1 O'

O

0)a

w

M

(U o' u

o

:iu

4JW

Ou

o

•HE

4-1O

C

O

•rH 4J

Cd

•rH u

cd >

u

(U rC

4J

4-1O

Xi

X)

•rHE

(U

4J

4J

Cd

m

0)u

d

40 *H

pCn

42
TRUE STRAIN

(a)

(b)

Figure 16. True a-e curves obtained in simulated CR-DQ experiments (see

Table 1); (a) treatment a in Table 1; (b) treatment c in

Table 1.

43
YIELD

STRENGTH

IN

TENSION,

MPa

ksi

100 120 140

YIELD STRENGTH IN COMPRESSION, MPa

Figure 17. Correlation of yield strengths in tension and yield strengths

in compression. Results of tension and compression at one

strength level were obtained from the same steel plate.

44
1000

!S>|

o O

C\J

o

o o

CO

o

CO

o o o

o o o

00 CO Tl- ^dlAl‘H10N3aiS

Mu

0) rO

w

w

u 3

o c

CJ

00

ou

:i00

*!—

I

45

KNOOP

HARDNESS,

kg/mm
Temperature,

Figure 19. The CCT diagram of microalloyed 1522 forging steel.

46
47

Figure

20.

Microstructures

of

1522

microalloyed

steel;

(a)

martensite

after

fast

cooling;

(b)

bainite

after

slow

cooling.
dl/dT, /xm/°C

Figure 21. Determination of phase- transformation temperatures using the

seven-point incremental polynomial technique. Bg : bainite

starts; Bf: bainite finishes; Mg : martensite starts; Mfi

martensite finishes.

48
160

o

edlAl ‘ssajts snji

49

Figure

22.

True

a-e

characteristic

of

1522

microalloyed

steel

at

1093®C

with

a

compressive

strain

rate

of

10

s“^.
Temperature

Figure 23. The CCT diagram of the 1141 microalloyed forging steel. Dashed

line is the typical cooling rate found in a forging without

forced cooling (Ref. 31).

50
20 Rc 29 Rc

20 jxm

Figure 24. Microstructures of the microalioyed 1141 steel with different

cooling rates, (a) ferrite plus pearlite; (b) peariite-ferrite

(Widmanstatten) plus small portion of bainite; (c) bainite plus

small portion of martensite; (d) martensite plus small portion

of bainite.

50 Rc 42 Rc

51
APPENDIX 1. Computer Program Listing for System Control and Data Acquisition

52
\ SYSTEM CONTROL AND DATA ACQUISITION PROGRAM

65280 SYSTEM. BUFFER. SIZE

DIM[ 10 , 50 ] STRING. ARRAY SCOPE. BACK

14 GPIB. DEVICE SCOPE SCOPE. BACK "GPIB . BUFFER

REAL DIM[ 50 ] ARRAY [] DATA. WAVETEK

2 GPIB. DEVICE WAVETEK [ ] DATA . WAVETEK [] GPIB . BUFFER

SEND . INTERFACE . CLEAR

REMOTE . ENABLE . ON

4000 TIMEOUT

REAL SCALAR TOTALtime

SCALAR DELAY

SCALAR EPStotai

SCALAR STRKFACTOR

SCALAR PFACTOR

SCALAR ACTUorCAGE

SCALAR VFACTOR

\ Conversion factor (stroke) : V to mm

\ Conversion factor (load) : V to kN

\ Checking if actuator or gage is used for strain

\ Starting point in displacement curve

on oscilloscope.

SCALAR AA

SCALAR VALVEfactor

SCALAR TEMP

SCALAR VTEMPmean

\ Temperature inputs

\

20 -point average for temperature determination

in mV

SCALAR VTEMP

SCALAR IstTEMP

SCALAR TT

INTEGER SCALAR NMAX

SCALAR ASCDIM

SCALAR ASCDIMl

40 STRING FILENAME

40 STRING FILENAME

1

20 STRING SPECIMEN. NAME

20 STRING MATERIAL

64 STRING TREATMENT

15 STRING TEST. DATE

\ Average mV for temperature checking

\ 1st compression temperature

\ Test temperature

53
20 STRING OPERATOR

64 STRING TEMPERATURE

64 STRING TEST. TYPE

64 STRING RESERVED

RAEL DIM[ 1000 ] ARRAY TTRANS

REAL DIM[ 1000 ] ARRAY DTRANS

REAL DIM[ 200 ] ARRAY VOLTOUT

REAL DIM[ 200 ] ARRAY TIMEI

REAL DIM[ 50 ] ARRAY PARAM

REAL DIM[ 1500 ] ARRAY PLOAD

REAL DIM[ 1500 ] ARRAY DISPL.

REAL DIM[ 1500 ] ARRAY STRESS

REAL DIM[ 1500 ] ARRAY STRAIN

REAL DIM[ 1500 ] ARRAY SIGMA

REAL DIM[ 1500 ] ARRAY EPSILON

REAL DIM[ 1500 ] ARRAY EPLAST

REAL DIM[ 1500 ] ARRAY L

REAL DIM[ 1500 ] ARRAY STS

REAL DIM[ 1500 ] ARRAY STN

REAL DIM[ 9 ] ARRAY deltaH

REAL DIM[ 9 ] ARRAY tTEMP

0. PARAM :=

0. PLOAD :=

0. DISPL.

0. STRESS

0. STRAIN

0. SIGMA :=

0. EPSILON :=

0. EPLAST :=

0. L : =

0. VOLTOUT :=

0. TIMEI :=

0. tTEMP :=

0. deltaH :=

0. STN :=

0. STS :=

\ Instantaneous gage length

54
0. TTRANS :=

0. DTRANS

DT2820

0 0 D/A. TEMPLATE DToA

1 1 D/A. TEMPLATE DToAl

3 3 A/D. TEMPLATE T

1 1 A/D. TEMPLATE G

." INPUT . PARAMETERS "

: INPUT . PARAMETERS \

ierk^'irkicifit^kickiclrk'irkick^'fc'k'k'k^kie'k'ic'fric'kic'fc'k'icirirk'k^'irie'k'k'k'k'k'k'k'k'k'k'k

0. PARAM : =

CR CR

.” Enter the specimen name (8 CHARACTERS EXACTLY !!!!!) " "INPUT

SPECIMEN. NAME ":=

CR CR ." Enter the material (20 CHARACTERS) " "INPUT . MATERIAL ":=

CR CR ." Enter the thermal treatment (64 CHARACTERS) " "INPUT

TREATMENT ":=

CR CR ." Enter the test date (MM/DD/YY) " "INPUT

TEST. DATE ":=

CR CR ." Enter the operator's name (20 CHARACTERS) " "INPUT

OPERATOR ":=

CR CR

." Enter the test temperatures for future record (64 CHARACTERS) " "INPUT

TEMPERATURE ":=

CR CR

." Enter the test type (Tension/Compression with/without ext. etc., (64 CHAR.) "

"INPUT

TEST. TYPE ":=

CR CR ." Enter any additional data (64 CHAR.) " "INPUT

RESERVED ":=

CR CR ." Hit 0 for TENSION or 1 for COMPRESSION " #INPUT

PARAM [ 2 ] := \ Tension/Compression

CR CR . " Enter the initial height of the stroke (mm) " #INPUT

PARAM [ 4 ] := CR CR . " Enter gage length Lo/Ho (mm) " #INPUT

PARAM [ 5 ] := \ Total initial length (Lo)

55
CR CR Enter specimen's area Ao (sq. mm) ” #INPUT

PARAM [ 6 ] := \ Initial area (Ao)

\ PARAM [ 16 ] is reserved for NMAX

CR CR Enter FILE NAME for data saving (20 CHAR.) " "INPUT

FILENAME ":=

SCREEN. CLEAR

CR CR . " How many hits do you want? (up to 10) " #INPUT

PARAM [ 1 ] := CR CR . " Enter how-many-N per 1 V (Newtons) " #INPUT

PFACTOR := CR CR . " Enter how-many-V (stroke) per 1 mm (volts) " #INPUT

STRKFACTOR := PFACTOR PARAM [ 3 ] := CR CR ." Enter 1 for ACTUATOR, 0 for GAGE " #INPUT

ACTUorGAGE := ACTUorGAGE PARAM [ 7 ] := CR CR ." Enter the desired true strain rate (1/s) " #INPUT

PARAM [ 19 ] := CR CR ." Enter the COOLING-RATE (0.= 0 V equivalent to valve close;

5.= 5 V equivalent to valve fully open) " #INPUT

VALVEfactor := VALVEfactor PARAM [ 17 ] := CR CR ." Enter the desired FINAL height after the 1st HIT (mm) " #INPUT

PARAM [ 21 ] := CR CR ." Enter the temperature (deg. C) for the 1st Hit " #INPUT

IstTEMP := IstTEMP PARAM [ 18 ] := CR CR

NORMAL. DISPLAY

PARAM [ 1 ] 1 > IF

PARAM [ 1 ] 1 DO

." Enter Delta-Height (mm) for hit No - " I 1 + . ." #INPUT

deltaH [ I ] ;=

CR CR

LOOP

deltaH [ 1 ] PARAM [ 8 ] := \ 2nd hit

56
deltaH [ 2 ] PARAM [ 9 ]

: = \ 3rd hit

deltaH [ 3 ] PARAM [ 10 ]

: = \ 4th hit

deltaH [ 4 ] PARAM [ 11 ]

: = \ 5 th hit

deltaH [ 5 ] PARAM [ 12 ]

; = \ 6 th hit

deltaH [ 6 ] PARAM [ 13 ]

: = \ 7 th hit

deltaH [ 7 ] PARAM [ 14 ]

: = \ 8 th hit

deltaH [ 8 ] PARAM [ 15 ]

: = \ 9 th hit

NORMAL .DISPLAY

PARAM [ 1 ] 1 DO

. " Enter the temperature (deg. C) for hit No " I 1 +

tTEMP [ I ]

: = CR CR

LOOP

tTEMP [ 1 ] PARAM [ 20 ]

: = \ 2nd hit temperature

tTEMP [ 2 ] PARAM [ 22 ]

: = \ 3rd

tTEMP [ 3 ] PARAM [ 42 ]

; = \ 4th

tTEMP [ 4 ] PARAM [ 43 ]

: = \ 5 th

tTEMP [ 5 ] PARAM [ 50 ]

: = \ 6 th

THEN

SCREEN. CLEAR

CR

CR CR CR CR

INVERSE. ON Important !!!! " INVERSE. OFF

#INPUT

. " After you return to the main menu type S to exit and enter a value for the

time INTERVAL (ms between dilation-temperature data points during cooling); '*

CR CR . " For example : "

CR CR CR ." 300. INTERVAL := "

CR CR CR ." Then, type NAR to return to the main menu and start the test "

CR CR CR CR ." Hit <RET> to continue " #INPUT

." SAVE . PARAMETERS "

: SAVE . PARAMETERS \

*^********T(tS!r*'i!r/r***S!f:fc***i(lnV**^Sf*'*************''***'*'**'A'*'3V'!Sf*

FILE . TEMPLATE

9 COMMENTS

REAL DIM[ 50 ] SUBFILE

REAL DIM[ 1500 ] SUBFILE

3 TIMES

57
REAL DIM[ 9 ] SUBFILE

2

TIMES

END

FILENAME DEFER> FILE. CREATE FILENAME DEFER> FILE. OPEN

FILENAME 1 >COMMENT

SPECIMEN. NAME 2 >COMMENT

MATERIAL 3 >COMMENT

TREATMENT 4 >COMMENT

TEST . DATE 5 >COMMENT

OPERATOR 6 >COMMENT

TEMPERATURE 7 >COMMENT

TEST. TYPE 8 >COMMENT

RESERVED 9 >COMMENT

1 SUBFILE PARAM ARRAY>FILE

2 SUBFILE PLOAD ARRAY>FILE

3 SUBFILE DISPL. ARRAY>FILE

4 SUBFILE L ARRAY>FILE

5 SUBFILE tTEMP ARRAY>FILE

6 SUBFILE deitaH ARRAY>FILE

FILE. CLOSE

>

." INITIALIZE. SYSTEM "

: INITIALIZE . SYSTEM \

0. PLOAD :=

0. DISPL. :=

0. STRESS :=

0. STRAIN ;=

0. SIGMA :=

0. EPSILON :=

0. EPLAST ;=

0. VOLTOUT :=

0. TIMEI :=

0. AA :=

0. STN :=

0. STS := DT2820 DtoA D/A.INIT 2048. D/A. OUT

58
DtoAl D/A.INIT 2048. D/A. OUT

: CHECK. TEMP \

NORMAL. DISPLAY

CR CR OR OR OR

INVERSE. ON

. " Waiting for the correct test temperature ! " INVERSE. OFF

BEGIN

0 . VTEMPmean :

T A/D.INIT

21 1 DO

A/D. IN VTEMPmean + VTEMPmean := LOOP

VTEMPmean 20. / 2048. - 2048. / 100. ^ VTEMP := VTEMP 130.268 * -3.8403 VTEMP 2. ** * + 0.104154

VTEMP 3. ** * + 11.7469 + TEMP := TEMP TT <=

UNTIL

: READ. TEMP. AND. DILATION \ Acquire dilation- temperature data during

cooling

SCREEN. CLEAR

CR CR CR CR CR

INVERSE. ON

Reading temperature and dilation data " INVERSE. OFF

1001 1 DO

T A/D.INIT A/D, IN TTRANS [ I ] ;=

G A/D.INIT A/D. IN DTRANS [ I ] := INTERVAL MSEC. DELAY

LOOP

TTRANS 2048. TTRANS := TTRANS 2048. / TTRANS := TTRANS 100. * TTRANS ;=

1001 1 DO

TTRANS [ I ] 3. ** 0.104154 * TTRANS [ I ] 2 . -3.8403 * + TTRANS [ I ] 130.268 * + 11.7469 + TTRANS [ I ] ;=

LOOP

59
DTRANS 2048.

STACK . CLEAR

2048. / -928.8878 * DTRANS :

: COMMUNICATE \ Initializing GPIB ******’'*****'ATfc’*'*''*'i*f'jV'jV

SCOPE. BACK "GPIB. BUFFER

ME TALKER SCOPE LISTENER OAH EOS . CHARACTER EOI.OFF EOS. ON

" C, 4, 1,44 " GPIB. WRITE 10 ASCII" GPIB. WRITE

ME LISTENER SCOPE TALKER

BUFFER. LISTEN

J

; COMPUTER. CONTROL

ME TALKER SCOPE LISTENER OAH EOS . CHARACTER EOI.OFF EOS. ON

" Z1 " GPIB. WRITE 10 ASCII" GPIB. WRITE

ME LISTENER SCOPE TALKER

BUFFER. LISTEN

9

: TRIGGER.SCOPE.RIGHT

ME TALKER SCOPE LISTENER OAH EOS . CHARACTER EOI.OFF EOS. ON

" H,l,2 " GPIB. WRITE 10 ASCII" GPIB. WRITE

ME LISTENER SCOPE TALKER

BUFFER. LISTEN

9

: TRIGGER. SCOPE. LEFT

ME TALKER SCOPE LISTENER OAH EOS . CHARACTER EOI.OFF EOS. ON

" H,l,l " GPIB. WRITE 10 ASCII" GPIB. WRITE

ME LISTENER SCOPE TALKER

BUFFER. LISTEN

9

: RECORD. SIGNAL

ME TALKER SCOPE LISTENER OAH EOS . CHARACTER EOI.OFF EOS. ON

" S, 0,0,0 " GPIB. WRITE 10 ASCII" GPIB. WRITE

ME LISTENER SCOPE TALKER

BUFFER. LISTEN

9

: CONTROL. BACK. TO. SCOPE

ME TALKER SCOPE LISTENER OAH EOS . CHARACTER EOI.OFF EOS. ON

60
•• ZO " GPIB. WRITE 10 ASCII" GPIB. WRITE

ME LISTENER SCOPE TALKER

BUFFER. LISTEN

9 GET. DATA ” \ Get data through A/D channel

: GET. DATA

DToA D/A.INIT

PARAM [ 4 ] PARAM [ 21 ] / LN EPStotal := EPS total PARAM [ 19 ] / TOTALtime := TOTALtime 5.0251 * DELAY := 201 1 DO

I 200. / TOTALtime * TIMEI [ I ] := TIMEI [ I ] PARAM [ 19 ] * -1. * EXP 0.5 * PARAM [ 4 ] * 2.5 /

VOLTOUT [ I ] := LOOP

VOLTOUT VOLTOUT [ 1 ] - AA + VOLTOUT := VOLTOUT [ 200 ] AA := VOLTOUT -10 10 D/A. SCALE VOLTOUT ;=

DELAY SYNC. PERIOD

SYNC. ERROR. OFF

SCOPE. BACK "GPIB. BUFFER

COMMUNICATE

COMPUTER. CONTROL

TRIGGER . SCOPE . RIGHT

100 MS EC. DELAY

201 1 DO \ Operating the stroke

SYNCHRONIZE

VOLTOUT [ I ] D/A. OUT

LOOP

RECORD. SIGNAL

CONTROL . BACK . TO . SCOPE

9 READ. ASCII \ ASCII TO ASYST 'kif'k'k'k'k'k'k'k'k'k'k'k'k'it'k'k'k'k'k'kic CR CR CR ." Enter the name of the ASCII LOAD file - " "INPUT

DEFER> BASIC. OPEN

61
BASIC. READ DROP

BEGIN

BASIC. READ DROP

CATENATE

7BASIC.EOF

UNTIL

BASIC. CLOSE

[]SIZE ASCDIM := SUB[ 1 , ASCDIM ] -1. * PLOAD SUB[ 1 , ASCDIM ] := CR CR CR ." Enter the name of the ASCII DISPLACEMENT file . . - " "INPUT

DEFER> BASIC. OPEN

BASIC. READ DROP

BEGIN

BASIC. READ DROP

CATENATE

7BASIC.EOF

UNTIL

BASIC. CLOSE

SUB[ 1 , ASCDIM ] -1. * DISPL. SUB[ 1 , ASCDIM ] := CR CR CR

INVERSE. ON

." Enter V factor for the displacement starting point (on oscilloscope,

negative V) "

CR CR #INPUT

VFACTOR := INVERSE. OFF

DISPL. VFACTOR + DISPL. := PLOAD PARAM [ 3 ] •^ PLOAD := \ Convert V to N(ewtons)

PARAM [ 7 ] 0 > IF

DISPL. STRKFACTOR * DISPL. := \ Convert V (actuator) to mm

ELSE

DISPL. 0.1011 DISPL. := \ Convert V (displacement gage) to mm

1 V = 0 . 1011 mm

THEN

PARAM [ 5 ] L [ 1 ] := ASCDIM 1 + 2 DO

L [ 1 ] DISPL. [ I ] - L [ I ] := LOOP

62
ASCDIM PARAM [ 16 ] := NORMAL. DISPLAY

9 SAVE. DATA ”

. SAVE . DATA \

." SAVE. DATA "

FILE. TEMPLATE

9 COMMENTS

REAL DIM[ 50 ] SUBFILE

REAL DIM[ 1500 ] SUBFILE

3 TIMES

REAL DIM[ 9 ] SUBFILE

2

TIMES

END

FILENAME DEFER> FILE. CREATE FILENAME DEFER> FILE. OPEN

FILENAME 1 >COMMENT

SPECIMEN. NAME 2 >COMMENT

MATERIAL 3 >COMMENT

TREATMENT 4 >COMMENT

TEST. DATE 5 >COMMENT

OPERATOR 6 >COMMENT

TEMPERATURE 7 >COMMENT

TEST. TYPE 8 >COMMENT

RESERVED 9 >COMMENT

1 SUBFILE PARAM ARRAY>FILE

2 SUBFILE PLOAD ARRAY>FILE

3 SUBFILE DISPL. ARRAY>FILE

4 SUBFILE L ARRAY>FILE

5 SUBFILE tTEMP ARRAY>FILE

6 SUBFILE deitaH ARRAY>FILE

FILE. CLOSE

9

." SAVE.DATAl "

; SAVE . DATAl \

^f(i('ki<irkirk^irickirkirki<i<irk'kirk'ki<'kirki<i<i<'kirk'k'k'i<'k‘k'k'k'k'ki<i('ki<'k'k'ki<'k'k^i<:k-k

." SAVE.DATAl "

FILE. TEMPLATE

63
9 COMMENTS

REAL DIM[ 50 ] SUBFILE

REAL DIM[ 1500 ] SUBFILE

3 TIMES

REAL DIM[ 9 ] SUBFILE

2

TIMES

END

FILENAMEl DEFER> FILE. CREATE FILENAMEl DEFER> FILE. OPEN

FILENAMEl 1 >COMMENT

SPECIMEN. NAME 2 >COMMENT

MATERIAL 3 >COMMENT

TREATMENT 4 >COMMENT

TEST. DATE 5 >COMMENT

OPERATOR 6 >COMMENT

TEMPERATURE 7 >COMMENT

TEST . TYPE 8 >COMMENT

RESERVED 9 >COMMENT

1 SUBFILE PARAM ARRAY>FILE

2 SUBFILE PLOAD ARRAY>FILE

3 SUBFILE DISPL. ARRAY>FILE

4 SUBFILE L ARRAY>FILE

5 SUBFILE tTEMP ARRAY>FILE

6 SUBFILE deltaH

FILE. CLOSE

ARRAY>FILE

>." REPEATED. HITS It

: REPEATED. HITS

PARAM [ 18 ] TT : CHECK . TEMP

GET . DATA

PARAM [ 1 ] 1 > IF

PARAM [ 1 ] 1 DO

PARAM [ 21 ] PARAM [ 4 ] := PARAM [ 21 ] deltaH [ I ] - PARAM [ 21 ] := tTEMP [ I ] TT := CHECK. TEMP

64
GET . DATA

FILENAME I 32 "COMPRESS "CAT FILENAMEl ":=

SAVE . DATAl

LOOP

THEN

50. MSEC. DELAY

DTOA D/A.INIT 40.96 5. * VOLTOUT [ 200 ] + D/A. OUT

." READ. FILE "

: READ. FILE \

CR ." Enter name of file you want to load " "INPUT

DEFER> FILE. OPEN

1 C0MMENT> FILENAME ":=

SPECIMEN. NAME ":=

MATERIAL

2 COMMENT>

3 COMMENT>

4 COMMENT>

5 COMMENT>

6 COMMENT>

7 COMMENT>

8 COMMENT>

9 COMMENT>

TREATMENT

TEST . DATE

OPERATOR

TEMPERATURE " :

TEST. TYPE ":=

RESERVED ":=

1 SUBFILE PARAM FILE>ARRAY

2 SUBFILE PLOAD FILE>ARRAY

3 SUBFILE DISPL. FILE>ARRAY

4 SUBFILE L FILE>ARRAY

5 SUBFILE tTEMP FILE>ARRAY

6 SUBFILE deltaH FILE>ARRAY

FILE. CLOSE

DT2820 DtOAl D/A.INIT 2048. D/A. OUT

DtoA D/A.INIT 2048. D/A. OUT

." SEE FILE "

: SEE . FILE \

'ff'fc'f<^'ki<ick'^icirkici(i<'ki<i(’kie^i<'ki(ie'ki(i<irk'ki<'ki<'k'ick'k’ki<'frk'k'k'k^'k'k'k'ki<'k'k'k'k'k'k'k-k

CR ." FILENAME - " FILENAME "TYPE

CR ." SPECIMEN. NAME - " SPECIMEN .NAME "TYPE

CR ." MATERIAL - " MATERIAL "TYPE

65
CR TREATMENT - " TREATMENT "TYPE

CR TEST. DATE - " TEST. DATE "TYPE

CR . " OPERATOR - " OPERATOR "TYPE

CR ." TEMPERATURE - " TEMPERATURE "TYPE

CR ." TEST. TYPE - " TEST. TYPE "TYPE

CR ." RESERVED - " RESERVED "TYPE

CR CR ." THE CURRENT VALUES ARE : I PARAM[I] "

51 1 DO PARAM [ I ] I

CR ” ” ” ”

PAUSE LOOP

CR CR ." THE DATA VALUES ARE: I LOAD DISPL. "

CR

1501 1 DO DISPL. [ I ] PLOAD [ I ] I

I? If II It II It

PAUSE ?KEY IF KEY DROP LEAVE THEN LOOP

." DEFINE . PARAMETERS "

: DEFINE . PARAMETERS \

************’'jV'**iSr*'*'*'**'**'*'*****'A'*’*'A’*''3Sf*''*'A’'s!c''**'^Sf'*****'j!('*'A'

CR . " Those are the names of the string parameters "

CR ." SPECIMEN. NAME FILENAME MATERIAL TREATMENT TEST. DATE

CR ." TEMPERATURE TEST. TYPE RESERVED OPERATOR "

CR . " Those are the meanings of the items in the PARAM array "

CR ." PARAM [ 1 ] - No of hits " CR . " 2 - Tension/Compression ( 0 - Tension )

" CR . " 3 - Load calibration factor (N per 1 V) " CR . " 4 - The initial height of the stroke above the lower anvil "

CR . " 5 - Gage length (Lo/Ho) " CR . " 6 - Initial area (Ao) " CR . " 7 - Actuator (param [7] = 1) or Displacement Gage (= 0) "

CR ." 8 - DELTA H in hit No 2

"

CR ." 9 - DELTA H in hit No 3

" CR ." 10 - DELTA H in hit No 4

"

CR ." 11 - DELTA H in hit No 5

" CR ." 12 - DELTA H in hit No 6

"

CR ." 13 - DELTA H in hit No 7

"

CR ." 14 - DELTA H in hit No 8

"

66
CR 15 - DELTA H in HIT No 9

"

CR 16 - No. of data points (NMAX) "

CR 17 - Cooling valve opening (V) "

CR 18 - 1st hit temperature "

CR 19 - Strain rate (1/s) "

CR 20 - 2nd hit temperature ''

CR 21 - HEIGHT after hit No. 1

"

CR 22 - 3rd hit temperature "

CR 23 - Stress at 0.01% "

CR 24 - Stress at 0.05% "

CR 25 - Stress at 0.1% '*

CR 26 - Stress at 0.2% "

CR 27 - Ultimate stress "

CR 28 - Ultimate strain *'

CR 29 - Fracture stress *'

CR 30 - Fracture strain "

CR 31 - Young ' s Modulus "

CR 32 - Proportional limit "

CR 33 - No. of point in P.L. "

CR 34 - K1 "

CR 35 - K2 " CR 36 - K3 '•

CR 37 - N1 "

CR 38 - N2 "

CR 39 - N3 ''

CR 40 - SLOPE "

CR 41 - INTERCEPT " CR 42 - 4th hit temperature "

CR 43 - 5th hit temperature "

CR 44 - 49 - Limits for N/K calculations

CR 50 - 6th hit temperature "

CR . To change a parameter, do (for example): 5 PARAM [ 6 ] CR

To change a string parameter, do (for example): '' CHENG '

9 CHANGE . PARAMETERS "

It

' OPERATOR '

67
: CHANGE . PARAMETERS \

^^^'kic^'icic'Mt^'k'irkick'icic'irfrk'ic'k^irk'ick'it'k'fc'icfrk'fcic'ic'k'k'irk'k'ic'ic'icicie^rlck'k CR ." After hitting a key you will return to the system. "

CR . " Change any parameters you want and type NAR to return to menu "

> CALCULATE. STRESS. STRAIN ''

: CALCULATE. STRESS . STRAIN \

*****************^iWWt swHHtvWf** SHWr*******

INVERSE. ON ." Please wait, I am THINKING ” INVERSE. OFF

1501 1 DO

PLOAD [ I ] PARAM [ 6 ] / STRESS [ I ] := DISPL. [ I ] PARAM [ 5 ] / 100. * STRAIN [ I ] := LOOP

9." SEE. CURVE "

; SEE . CURVE \

*^Wf********'jV*'*******TBf*****Tlt*****T!t***^Sr**'s5nllf*'****'A’********'*'**

AXIS. DEFAULTS

STRAIN SUB[ 2 , PARAM [ 16 ] 1 - ] STRESS SUB[ 2 , PARAM [ 16 ] 1 - ] XY. AUTO. PLOT

NORMAL. COORDS

0.5 0.05 POSITION " Strain, % " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " Stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD. COORDS

CR . " Hit any key to continue " KEY DROP

NORMAL. DISPLAY

9

NORMAL. DISPLAY INVERSE. ON

CR CR CR ." An ASCII file named ******. DAT will be created. "

CR CR CR CR CR ." Hit any No key and <RET> to start data -conversion ” #INPUT

INVERSE. OFF DROP

CR CR CR

STRESS SUB[ 1 , PARAM [ 16 ] 1 - 3 / , 3 ] []SIZE ASCDIMl :=

68
STRESS SUB[ 1 , PARAM [ 16 ] 1 - 3 / , 3 ] STS SUB[ 1 , ASCDIMl ] := STRAIN SUB[ 1 , PARAM [ 16 ] 1 - 3 / , 3 ] STN SUB[ 1 , ASCDIMl ] := SCREEN. CLEAR

CR CR CR CR CR CR

Enter a name for the ASCII output file (8 chars.DAT) "

CONSOLE. OFF "INPUT

DEFER> OUT>FILE

ASCDIMl 1 + 1 DO

STN [ I ]

. " STS [ I ]

. CR

LOOP

OUT>FILE. CLOSE

9." GO. ON "

: GO . ON \

'ickirk'k^'k'fcirkic’k^irk'kirki<*'k'k:k:k'kici<'k'kirk^i<'ic'kici('ki<i(i<icic'k-kici(ici<ie'k’iric'k'ic'i('k'ic’k'k‘k'i<

CR CR . " Hit any key to continue " KEY DROP

9

: SEND. WAVETEK. SIGNAL \ Shut-off the induction generator

ME TALKER WAVETEK LISTENER

" P1F0.5A5D0B1O1C0IJ " GPIB. WRITE

: OPEN . VALVE \

'fc'ffie'k'k'kide'k'k'k^irk'k'k'k Start forced cooling '*****'*"**’**'*"**"**'*' DtoAl D/A.INIT

2048. 10. / PARAM [ 17 ] * 2048. + D/A. OUT

9." NAR "

: NAR \

'frk'k'k'k'k'k'ick'k'k'kic'k'irk'k'k'k Program Starting word 'k'it'fc'k'ie'ie'k'k'fc'k'k'k'k'k'ii'k^'k'k'kit'fck NORMAL. DISPLAY

1501 1 DO

SCREEN. CLEAR INTEN.ON INVERSE. ON

." F&D Dv.: THERMOMECHANICAL PROCESSING GROUP -INTERACTIVE TESTING PROGRAM "

CR CR

INTEN.OFF INVERSE. OFF

. " Enter parameters for a new test HIT 1

"

CR CR ." Start test HIT 2

"

CR CR .

View S/e (engineering) curve HIT 3

"

69
CR CR

CR CR

CR CR

CR CR

CR CR

CR CR

CR CR

CR CR

CR CR

KEY

CASE

Parameters definition HIT 4

"

Load file HIT 5

"

Change file HIT 6

"

See file HIT 7

'•

Save file HIT 8

"

Convert ASCII data (*******. AD file) to ASYST, HIT 9

" Convert ASYST data-file to ASCII (create  .DAT file), HIT 0

"

QUIT HIT S

"

49 OF INPUT . PARAMETERS SAVE . PARAMETERS INITIALIZE . SYSTEM ENDOF

50 OF INITIALIZE. SYSTEM

COMMUNICATE

COMPUTER . CONTROL

TRIGGER . SCOPE . RIGHT

REPEATED. HITS

RECORD. SIGNAL

GONTROL . BACK . TO . SCOPE

COMMUNICATE

COMPUTER. CONTROL

SEND. WAVETEK. SIGNAL

TRIGGER . SCOPE . LEFT

CONTROL . BACK . TO . SCOPE

OPEN. VALVE

READ . TEMP . AND . DILATION

ENDOF

51 OF CALCULATE. STRESS. STRAIN SEE. CURVE ENDOF

52 OF DEFINE . PARAMETERS GO. ON ENDOF

53 OF READ. FILE GO. ON ENDOF

54 OF CHANGE . PARAMETERS GO. ON LEAVE ENDOF

55 OF SEE. FILE GO. ON ENDOF

56 OF SAVE. DATA ENDOF

57 OF READ. ASCI I SAVE. DATA ENDOF

48 OF READ. FILE CALCULATE . STRESS . STRAIN CONVERT . TO .ASCII ENDOF

83 OF LEAVE ENDOF

70

APPENDIX 2 Computer Program Listing for Post-Test Data Analysis

72
\ DATA ANALYSIS AND SUMMARIZING REPORT PRODUCTION PROGRAM

REAL SCALAR II

SCALAR INDEX

SCALAR SLOPE

SCALAR INTERCEPT

SCALAR RIGHT

SCALAR LEFT

SCALAR LEFTl

SCALAR RANGE

SCALAR K1

SCALAR N

DIM[ 25 , 20 ] STRING. ARRAY FILENAMES

REAL DIM[ 1500 ] ARRAY E

REAL DIM[ 1500 ] ARRAY S

REAL DIM[ 1500 ] ARRAY YLEAST

REAL DIM[ 1500 ] ARRAY XLEAST

REAL DIM[ 2 ] ARRAY XYLEAST

REAL DIM[ 4 ] ARRAY CURSOR. POSITION

REAL DIM[ 25 ] ARRAY STATIS

REAL DIM[ 25 ] ARRAY STATISl

REAL DIM[ 25 ] ARRAY MEANS

REAL DIM[ 25 ] ARRAY SDEV

REAL DIM[ 25 ) 10 ] ARRAY TABLE4

REAL DIM[ 25 1 12 ] ARRAY TABLE5

0. YLEAST :=

0. XLEAST :=

0. XYLEAST :=

0. STATIS :=

0. STATISl :=

0. MEANS :=

0. SDEV :=

0. TABLE4 :=

0. E : =

73
0. S ; = VUPORT VUl

0 0.21 VUPORT. ORIG

1 0.79 VUPORT. SIZE

20 0 25 80 WINDOW VU2

." GO. ONI "

CR . ” Enter 1 to continue : BEGIN

#INPUT 1 = IF EXIT THEN

AGAIN

>.” A

"

: A \ ** ************ EPLAST, SIGMA, EPSILON Calculations ****************

INVERSE. ON ." Please wait " INVERSE. OFF

PARAM [ 33 ] 1 DO

0. EPLAST [ I ] := LOOP

PARAM [ 16 ] 1 + PARAM [ 33 ] DO

STRESS [ I ] 0. > IF

STRAIN [ I ] 100. / STRESS [ I ] PARAM [ 41 ] - PARAM [ 31 ] /

- EPLAST [ I ]

THEN

LOOP

PARAM [ 2 ] 0 >

IF

1. EPLAST - STRESS * SIGMA :=

PARAil [ 16 ] 1 + 2 DO

L[I1-]L[I]-L[I]/ EPSILON [11-]:=

LOOP

EPSILON ^SUM EPSILON := ELSE

1 . EPLAST +

STRESS * SIGMA := PARAM [ 16 ] 1 + 2 do

74
L[I]L[Il-]-L[Il-]/ EPSILON [ I 1 - ] := LOOP

EPSILON ^SUM EPSILON := THEN

NKTABLE "

: NKTABLE \

irkicirk'irk'kick‘kie'iei<^ki(irk'ki<^'kirkirk'ie^'ki<ick'kie'krk'irk^rk:krk-i(-k^'k'k'ie'i(^'k'k'k'k'ki<'k'i<-k-k'i<

CR CR

Specimen N1 K1 N2 K2 N3 K3 "

CR

. " name MPA MPA MPA

CR

II If

CR

DUP

1 + 1 DO

CR

FILENAMES "[ I ] "TYPE

12 3 FIX. FORMAT

TABLES [1,1].

10 0 FIX. FORMAT

TABLES [1,2].

10 3 FIX. FORMAT

TABLES [1,3] . 10 0 FIX. FORMAT

TABLES [1,4] . 10 3 FIX. FORMAT

TABLES [ I , S ]

. 10 0 FIX. FORMAT

TABLES [1,6].

LOOP

CR

" It

-1 4 FIX. FORMAT

1 + 1 DO

CR

7S
I . TABLES [1,7]. TABLES [ I , 10 ]

.

.

TABLES [1,8]. TABLES [ I , 11 ]. ."

TABLES [1,9]. TABLES [ I , 12 ]

. ."

LOOP

}." SEE. CURVE 1

"

: SEE . CURVE1 \

ie'f(*’kie^ic'kici<i(i<'krk^ic^ieieieirki<irkic^ickirki<ieirkicicicicicki<’k'frk'kirfck'kickirk'k'k'kie

LOAD. OVERLAY MATFIT.SOV

VERTICAL LINEAR

HORIZONTAL LINEAR

STACK. CLEAR

-1 4 FIX. FORMAT

GRAPHICS. DISPLAY VUl VU2

CR ." Hit 1 to calculate Young's modulus, 2 to calculate UTS " #INPUT

1 = IF

BEGIN

STRAIN SUB[ 2 , PARAM [ 16 ] 1 - ] STRESS SUB[ 2 , PARAM [ 16 ] 1 - ] XY. AUTO. PLOT

NORMAL. COORDS

O.S O.OS POSITION " Strain, % " LABEL

90 LABEL. DIR

90 CHAR. DIR

O.OIS 0.3 POSITION CURSOR. OFF " Stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD. COORDS

ARRAY. READOUT

CR . ” Place left cursor to define a zone for magnification *'

GO. ONI

READOUT. INDICES

1 + RIGHT :=

1 + LEFTl ;=

BEGIN

STRAIN SUB[ 2 , LEFTl ] STRESS SUB[ 2 , LEFTl ] XY. AUTO. PLOT

NORMAL. COORDS

76
0.5 0.05 POSITION " Strain, % ” LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " Stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD . COORDS

ARRAY. READOUT

SCREEN. CLEAR CR . " Define a line for Y.M. and " GO. ONI

READOUT. INDICES

1 + RIGHT :=

1 + LEFT := LEFT 1 = IF 2 LEFT := THEN

RIGHT LEFT - RANGE := XLEAST []RAMP

WITHOUT. WEIGHTS

STRAIN SUB[ LEFT , RANGE ] STRESS SUB[ LEFT , RANGE ] 1 LEASTSQ. POLY. FIT

XYLEAST := XYLEAST [ 1 ] SLOPE := SLOPE PARAM [ 40 ] := XYLEAST [ 2 ] INTERCEPT

INTERCEPT PARAM [ 41 ] XLEAST XLEAST [ RIGHT ] / STRAIN [ RIGHT ] * XLEAST := XLEAST SLOPE * INTERCEPT + YLEAST := LEFTl LEFT - RANGE := RANGE PARAM [ 16 ] > IF PARAM [ 16 ] LEFT - RANGE := THEN

XLEAST SUB[ LEFT , RANGE ] YLEAST SUB[ LEFT , RANGE ] XY. AUTO. PLOT

NORMAL. COORDS

0.5 0.05 POSITION " Strain, % " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " Stress, Mpa '' LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD . COORDS

77
STRAIN SUB[ LEFT , RANGE ] STRESS SUB[ LEFT , RANGE ] XY. DATA. PLOT

NORMAL. COORDS

0.5 0.05 POSITION ” Strain, % " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " Stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD . COORDS

SLOPE 100. * PARAM [ 31 ] := SCREEN. CLEAR

CR ." Y. Module = " PARAM [ 31 ]. CR . '' Hit 1 to recalculate "

CR ." Hit 2 to continue (P.L.) ” #INPUT

2 = UNTIL

ARRAY. READOUT

SCREEN. CLEAR

CR . ” Mark P.L. with right cursor and '•

GO. ONI

READOUT. INDICES

LEFT + PARAM [ 33 ] := LEFT + LEFT := STRESS [ PARAM [ 33 ] ] DUP PARAM [ 32 ] := CR .» P.L. = " . CR .

Hit 1 to recalculate "

CR . " Hit 2 to continue (UTS) '• #INPUT

2 = UNTIL

THEN

STRAIN SUB[ 2 , PARAM [ 16 ] 1 - ] STRESS SUB[ 2 , PARAM [ 16 ] 1 - ] XY. AUTO. PLOT

NORMAL. COORDS

0.5 0.05 POSITION " Strain, % " LABEL

90 LABEL. DIR

90 CHAR. DIR

78
0.015 0.3 POSITION CURSOR. OFF " Stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD . COORDS

ARRAY. READOUT

SCREEN. CLEAR

CR . ” Define a zone for UTS, use INS and "

GO. ONI

GRAPHICS. READOUT

CURSOR. POSITION

READOUT>ARRAY

SCREEN. CLEAR

CR ." Type *** HOME *** and "

GO. ONI

CURSOR. POSITION [ 2 ] PARAM [ 27 ] := CURSOR. POSITION [ 1 ] 100 / PARAM [ 27 ] PARAM [ 41 ] PARAM [ 31 ] /

- 100 * PARAM [ 28 ] := SCREEN. CLEAR

PARAM [ 27 ] CR . " Ultimate stress = '' PARAM [ 28 ] CR ." Ultimate strain = " . GO. ONI

STRAIN SUB[ 2 , PARAM [ 16 ] 1 - ] STRESS SUB[ 2 , PARAM [ 16 ] 1 - ] XY. AUTO. PLOT

NORMAL. COORDS

0.5 0.05 POSITION " Strain, % " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " Stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD . COORDS

ARRAY. READOUT

SCREEN. CLEAR

CR . Define a zone for FRACTURE, use INS and "

GO . ONI

GRAPHICS. READOUT

79
CURSOR. POSITION

READOUT>ARRAY

SCREEN. CLEAR

CR . " Type *** HOME *** and "

GO. ONI

CURSOR. POSITION [ 2 ] PARAM [ 29 ] := CURSOR. POSITION [ 1 ] 100 / PARAM [ 29 ] PARAM [ 41 ] - PARAM [ 31 ] /

- 100 * PARAM [ 30 ] := SCREEN. CLEAR

PARAM [ 29 ] CR . " Fracture stress = "

PARAM [ 30 ] CR . " Fracture strain = "

GO. ONI

NORMAL. DISPLAY PREVIOUS .WINDOW DEF.VUPORT

A

SCREEN. CLEAR

CR . " Hit 1 for N/K calculations, 2 to QUIT " #INPUT

1 = IF

4 1 DO

BEGIN

GRAPHICS. DISPLAY VUl VU2

PARAM [ 16 ] 1 + 1 DO

EPSILON [ I ] 0. <= IF I INDEX := THEN

LOOP

PARAM [ 16 ] INDEX - 4 - 1 INDEX + DO

EPSILON [ I ] LOG E [ I ] := SIGMA [ I ] LOG S [ I ] := LOOP

E S XY. AUTO. PLOT

NORMAL. COORDS

0.5 0.05 POSITION " Log true strain " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " Log true stress " LABEL

0 LABEL. DIR

0 CHAR. DIR

80
WORLD . COORDS

ARRAY. READOUT

SCREEN. CLEAR

." Mark an area for fitting "

GO. ONI

READOUT. INDICES

RIGHT :=

1 INDEX + RIGHT + RIGHT ;=

LEFTl :=

1 INDEX + LEFTl + LEFTl := RIGHT LEFTl - RANGE := WITHOUT. WEIGHTS

EPSILON SUB[ LEFTl , RANGE ] LOG

SIGMA SUB[ LEFTl , RANGE ] LOG 1 LEASTSQ . POLY. FIT

XYLEAST := XYLEAST [ 1 ] N := 10 XYLEAST [ 2 ] ** K1 := SCREEN. CLEAR . N = " N . . " K = " K1 .

. " El = " EPSILON [ RIGHT ]

.

." E2 = " EPSILON [ LEFTl ]

. CR ." Hit 1 to save values, 2 to recalculate " #INPUT

1. = UNTIL

EPSILON [ LEFTl ] PARAM [ 43 I + ] := EPSILON [ RIGHT ] PARAM [ 46 I + ] ;=

K1 PARAM [ 33 I + ] := N PARAM [ 36 I + ] := CR ." Hit 3 to EXIT N/K calculations " #INPUT

3 = IF LEAVE THEN

LOOP

THEN

VERTICAL LINEAR

HORIZONTAL LINEAR

9." SPECIAL. POINTS 1

"

! SPECIAL . POINTSl \

iSnBf**'**'*****^^*’***^^*'*^^****' '** *'****'***^^*’'*'**'*'*'*'*****''*''*

81
PARAM [ 16 ] 1 + 1 DO DUP EPLAST [ I ] < IF LEAVE THEN I II := LOOP II PARAM [ 16 ] = IF DROP 0. THEN

EPLAST [ II 1 - ] - EPLAST [ II ] EPLAST [ II 1 - ] - /

STRESS [ II ] STRESS [ II 1 - ] - * STRESS [ II 1 - ] +

SPECIAL. POINTS "

: SPECIAL . POINTS \

****Vr'**:fc************V!f************'*'**'*’s!f*'***'’s!r*****'’*’*****

100. EPLAST *’ EPLAST := \ Changing EPLAST to percents

0 PARAM [ 23 ] :=

0 PARAM [ 24 ] :=

0 PARAM [ 25 ] :=

0 PARAM [ 26 ] := 0.01 SPECIAL. POINTS

1

PARAM [ 23 ]

: = 0.05 SPECIAL. POINTSl PARAM [ 24 ]

: =

0.1 SPECIAL. POINTSl PARAM [ 25 ]

: =

0.2 SPECIAL. POINTSl PARAM [ 26 ]

: =

." TABLEl '•

: TABLEl \

**'*******'3V'***'*’****'*’*'***'**'***’*'^**^*')Sf'*’*'***iSf*******'**''!Sr*'*'**'*'iSf*'*****

SCREEN. CLEAR

." Specimen Y. Modulus P.L. | Plastic Yield | S.U. E.U. S.F. "

. " E

.

F

•'

CR

name MPA MPA |.01% .05% 0.1% 0 . 2% | MPA % MPA "

. " %

"

CR

CR ; ." TABLE2 "

: TABLE2 \

'*•*********vsr vtvt** 'A'**v^*****^v**iit'*'*^v****'5Sf

1 + 1 DO

CR

FILENAMES "

[ I ] "TYPE

12 0 FIX. FORMAT

TABLE4 [1,1].

82
6 0 FIX. FORMAT

TABLE4 [1,2] .

7 0 FIX. FORMAT

TABLE4 [1,3] .

6 0 FIX. FORMAT

TABLE4 [1,4] .

6 0 FIX. FORMAT

TABLE4 [1,5].

7 0 FIX. FORMAT

TABLE4 [1,6].

6 0 FIX. FORMAT

TABLE4 [1,7] .

6 1 FIX. FORMAT

TABLE4 [1,8] .

7 0 FIX. FORMAT

TABLE4 [1,9].

6 1 FIX. FORMAT

TABLE4 [ I , 10 ]

. -1 4 FIX. FORMAT

LOOP

OR

9

." STATS "

: STATS \

’ff^'ic'k'k’kic'k'k^'kic'k'k-k'k'k^'k'ic'k'kic'k'k'k'k-k'k'k'ic-k'kicrkic'k'k'k^'ic'k'k-kif'fck'kic^'k'k'k'k'k'k'k'k-k'k^'frk STATISl :=

0. INDEX :=

11 1 DO

STATISl [ I ] 0. >

IF INDEX 1 + INDEX := STATISl [ I ] STATIS [ INDEX ] ;= ELSE THEN LOOP

9." TABLES '•

: TABLES \

0. TABLE4 :=

0. TABLES ;=

OR . '* How many specimens for table? " #INPUT DUP DUP

83
1 + 1 DO

READ. FILE

PARAM [ 31 ] TABLE4 [ I > 1 ]

: = PARAM [ 32 ] TABLE4 [ I 9 2 ]

: = PARAM [ 23 ] TABLE4 [ I 9 3 ]

: = PARAM [ 24 ] TABLE4 [ I 9 4 ]

: = PARAM [ 25 ] TABLE4 [ I 9 5 ]

: = PARAM [ 26 ] TABLE4 [ I 9 6 ]

: = PARAM [ 27 ] TABLE4 [ I 7 ]

: = PARAM [ 28 ] TABLE4 [ I 8 ]

: = PARAM [ 29 ] TABLE4 [ I 9 ]

: = PARAM [ 30 ] TABLE4 [ I 10 ]

: = PARAM [ 37 ] TABLE

5

[ I 1 ]

: = PARAM [ 34 ] TABLE

5

[ I 2 ]

: = PARAM [ 38 ] TABLE5 [ I 3 ]

: = PARAM [ 35 ] TABLE

5

[ I 4 ]

: = PARAM [ 39 ] TABLE5 [ I 9 5 ]

: = PARAM [ 36 ] TABLE

5

[ I 9 6 ]

: = PARAM [ 44 ] TABLE5 [ I 9 7 ]

: = PARAM [ 45 ] TABLE

5

[ I 9 8 ]

: = PARAM [ 46 ] TABLE

5

[ I 9 9 ]

: = PARAM [ 47 ] TABLE

5

[ I 9 10 ]

: = PARAM [ 48 ] TABLE

5

[ I 9 11 ]

: = PARAM [ 49 ] TABLE

5

[ I 9 12 ]

: = LOOP

CR . " Arrange paper and hit 1 to print on printer

#INPUT 1 = IF OUT>PRINTER THEN

TABLE

1

TABLE

2

CR

tt

11 1 DO

TABLE4 XSECT[ ! , I ] STATS

STATIS SUB[ 1 , INDEX ] MEAN MEANS [ I ] :=

84
INDEX 2 < IF 0. SDEV [ I ] := ELSE

STATIS SUB[ 1 , INDEX ] SAMPLE .VARIANCE SQRT SDEV [ I ] := THEN LOOP

CR AVERAGE "

12 0 FIX. FORMAT

MEANS [ 1 ].

6 0 FIX. FORMAT

MEANS [ 2 ]

.

7 0 FIX. FORMAT

MEANS [ 3 ]

.

6 0 FIX. FORMAT

MEANS [ 4 ]

.

6 0 FIX. FORMAT

MEANS [ 5 ]

.

7 0 FIX. FORMAT

MEANS [ 6 ]

.

6 0 FIX. FORMAT

MEANS [ 7 ]

.

6 1 FIX. FORMAT

MEANS [ 8 ]

.

7 0 FIX. FORMAT

MEANS [ 9 ]

.

6 1 FIX. FORMAT

MEANS [ 10 ]

. CR ." S. DEV. "

12 0 FIX. FORMAT

SDEV [ 1 ]

.

7 1 FIX. FORMAT

SDEV [ 2 ]

. SDEV [ 3 ]

.

6 1 FIX. FORMAT

SDEV [ 4 ]

. SDEV [ 5 ]

.

7 1 FIX. FORMAT

SDEV [ 6 ]

.

6 1 FIX. FORMAT

SDEV [ 7 ]

.

85
5 1 FIX. FORMAT

SDEV [ 8 ].

8 1 FIX. FORMAT

SDEV [ 9 ]

.

5 1 FIX. FORMAT

SDEV [ 10 ].

-1 4 FIX. FORMAT

CR

If _

ft NKTABLE

CONSOLE

f

. " PLOTTERl •'

; PLOTTERl \

LOAD . OVERLAY HPPLOTR . SOV

HP7475

PLOTTER. DEFAULTS

7 10 PLOTTER. SIZE

1 COLOR

NORMAL . COORDS

30. SLANT 0.35 0.99 POSITION " TMP group " LABEL 0. SLANT

0.85 0.99 POSITION FILENAME LABEL

WORLD . COORDS

I

. ” PLOTTERS ” \

**'jV***'*'**'***''***’***'***'*'Ve^*********^ :(t** *'5WlfVWr*i!Hrrfr****'**’***

: PLOTTERS

NORMAL. COORDS

0.88 0.05 POSITION " e (%) " LABEL

0.18 0.99 POSITION " S (MPA) " LABEL

WORLD . COORDS

)

. " PLOTTERS '* \

: PLOTTERS

NORMAL. COORDS

0.83 0.08 POSITION " Log Epsilon " LABEL

86
0.17 0.99 POSITION " Log Sigma " LABEL

WORLD . COORDS

." PLOTTER16 ” \

: PLOTTER16

NORMAL. COORDS

0.85 0.08 POSITION " Epsilon " LABEL

0.17 0.99 POSITION " Sigma " LABEL

WORLD . COORDS

9." PLOTTER2 "

: PLOTTER2 \

STRAIN SUB[ 2 , PARAM [ 16 ] 1 - ] STRESS SUB[ 2 , PARAM [ 16 ] 1 - ] XY. AUTO. PLOT

9." PLOTTERS "

: PLOTTERS \

*******vwt**iJnV*vif****')i!rtWf**vt********'*'***********' '** *')V**'*****

STRAIN SUB[ 2 , LEFTl ] STRESS SUB[ 2 , LEFTl ] XY. AUTO. PLOT

9." PLOTTER7 "

: PLOTTER? \

EPSILON SUB[ 1 INDEX + , PARAM [ 16 ] INDEX - 5 - ] LOG

SIGMA SUB[ 1 INDEX + , PARAM [ 16 ] INDEX - 5 - ] LOG XY. AUTO. PLOT

9." PLOTTER17 '•

: PLOTTER17 \

EPSILON SUB[ 1 INDEX + , PARAM [ 16 ] INDEX - 5 - ] SIGMA SUB[ 1 INDEX + , PARAM [ 16 ] INDEX - 5 - ] XY. AUTO. PLOT ; ." RETURN. PEN "

: RETURN . PEN \

'ick'icirkick'k'k'k'k'k'k'ie’ic'k'k^'frk'k'icifi<'k^'k'ic'k'k'k'i<'k'i<'k'i<'kie:k'k'k^i<ie'ki<'k’k'k'k:f('k'i<'k'k'k'i(

" SP; " GRAPH . COMMAND GRAPHICS . DISPLAY

9." PL0TTER4 "

: PLOTTER4 \

2 COLOR

0 XLEAST :=

87
0 YLEAST := XLEAST []RAMP

XLEAST XLEAST [ PARAM [ 33 ] 20 + ] / STRAIN [ PARAM [ 33 ] 20 + ] * XLEAST

XLEAST PARAM [ 40 ] * PARAM [ 41 ] + YLEAST := 501 1 DO YLEAST [ I ] 0. > IF LEAVE THEN I INDEX := LOOP

XLEAST SUB[ INDEX , PARAM [ 33 ] INDEX - 5 + ] YLEAST

SUB[ INDEX , PARAM [ 33 ] INDEX - 5 + ] XY. DATA. PLOT

9 PLOT. DATA "

; plot . DATA \

BEGIN

GRAPHICS. DISPLAY

VERTICAL GRID. OFF HORIZONTAL GRID. OFF

STRAIN SUB[ 2 , PARAM [ 16 ] 1 - ] STRESS SUB[ 2 , PARAM [ 16 ] 1 - ] XY. AUTO. PLOT

NORMAL. COORDS

0.5 0.05 POSITION " Strain, % " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " Stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD . COORDS

SCREEN. CLEAR CR ." Hit 1 to plot on PLOTTER, 2 to continue " #INPUT 1 = IF

PLOTTERl PLOTTER5 PLOTTER2 PL0TTER4 RETURN. PEN

THEN

STRAIN SUB[ 2 , PARAM [ 16 ] 1 - ] STRESS SUB[ 2 , PARAM [ 16 ] 1 - ] XY. AUTO. PLOT

NORMAL. COORDS

0.5 0.05 POSITION " Strain, % " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " Stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

88
WORLD . COORDS

ARRAY. READOUT

SCREEN. CLEAR CR GO. ONI

READOUT. INDICES

1 + RIGHT :=

1 + LEFTl := STRAIN SUB[ 2 , LEFTl ] STRESS SUB[ 2 , LEFTl ] XY. AUTO. PLOT

NORMAL. COORDS

0.5 0.05 POSITION " Strain, % " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " Stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD . COORDS

SCREEN. CLEAR CR

." Hit 1 to plot on PLOTTER, 2 to continue " #INPUT 1 = IF

PLOTTERl PLOTTERS PLOTTERS PL0TTER4 RETURN. PEN

THEN

SCREEN. CLEAR CR

." Hit 1 to PLOT again, 2 to STOP " #INPUT 2 = UNTIL

AXIS . DEFAULTS

1." PLOT.DATAll "

: PLOT . DATAl 1 \

'fe^'fiickie'k'k'kie-k'irick'fe’k'k'k'k'k'lricickic'k'k'k'ic-kic'k'icic'icic'ic'k'ie'kic^'k'k'kic-k'ic^ic'k'ic'k'k'k-k'k BEGIN

GRAPHICS. DISPLAY

VERTICAL GRID. OFF HORIZONTAL GRID. OFF

PARAM [ 16 ] 1 + 1 DO

EPSILON [ I ] 0. <= IF I INDEX := THEN

LOOP

PARAM [ 16 ] INDEX - 4 - 1 INDEX + DO

EPSILON [ I ] LOG E [ I ] := SIGMA [ I ] LOG S [ I ] :=

89
LOOP

E S XY. AUTO. PLOT

NORMAL. COORDS

0.5 0.05 POSITION " True strain (LOG) " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " True stress, Mpa (LOG) " LABEL 0 LABEL. DIR

0 CHAR. DIR

WORLD . COORDS

SCREEN. CLEAR CR ." Hit 1 to plot on PLOTTER, 2 to continue " #INPUT 1 = IF

PLOTTERl PLOTTER6 PLOTTER? RETURN. PEN

THEN

SCREEN. CLEAR CR

." Hit 1 to PLOT again, 2 to STOP " #INPUT 2 = UNTIL

AXIS. DEFAULTS

1." PLOT.DATA12 "

: PLOT . DATAl 2 \

****'*^****'3V**’jV**********'#r*****'rfr******************'*****'**’*’

BEGIN

GRAPHICS. DISPLAY

VERTICAL GRID. OFF HORIZONTAL GRID. OFF

PARAM [ 16 ] 1 + 1 DO

EPSILON [ I ] 0. <= IF I INDEX := THEN

LOOP

EPSILON SUB[ 1 INDEX + , PARAM [ 16 ] INDEX - 5 - ] SIGMA SUB[ 1 INDEX + , PARAM [ 16 ] INDEX - 5 - ] XY. AUTO. PLOT NORMAL. COORDS

0.5 0.05 POSITION " True strain " LABEL

90 LABEL. DIR

90 CHAR. DIR

0.015 0.3 POSITION CURSOR. OFF " True stress, Mpa " LABEL

0 LABEL. DIR

0 CHAR. DIR

WORLD . COORDS

SCREEN. CLEAR CR . Hit 1 to plot on PLOTTER, 2 to continue "

90
#INPUT 1 = IF

PLOTTERl PLOTTER16 PLOTTER17 RETURN. PEN

THEN

SCREEN. CLEAR CR

." Hit 1 to PLOT again, 2 to STOP "

#INPUT 2 = UNTIL

AXIS. DEFAULTS

.” PLOT.DATAl " \

: PL0T.D4TA1

SCREEN. CLEAR

." Hit 1 to get Sigma/Epsilon plots "

#INPUT

1 = IF PLOT.DATAl 2 THEN

. " Hit 1 to get LOG Sigma / LOG Epsilon plots "

#INPUT

1 = IF PLOT.DATAll THEN

: CONVERT. TO. ASCI II \

NORMAL. DISPLAY INVERSE. ON

CR CR CR ." An ASCII file named ********. DAT will be created. "

CR CR CR CR CR ." Hit any No key and <RET> to start data -conversion

#INPUT INVERSE. OFF DROP

CR CR CR

SIGMA SUB[ 1 , PARAM [ 16 ] 1 - 3 / , 3 ] []SIZE ASCDIMl := SIGMA SUB[ 1 , PARAM [ 16 ] 1 - 3 / , 3 ] STS SUB [ 1 , ASCDIMl ] := EPSILON SUB[ 1 , PARAM [ 16 ] 1 - 3 / , 3 ] STN SUB [ 1 , ASCDIMl ] SCREEN. CLEAR CR CR CR CR CR CR CR

." Enter a name for the ASCII output file (8 chars.DAT) "

CONSOLE. OFF

"INPUT DEFER> OUT>FILE

ASCDIMl 1 + 1 DO

STN [ I ]

. " STS [ I ]

. CR

LOOP

OUT>FILE. CLOSE

91
YNG "

; YNG \

'ic'ieickickicirkicic'k'k'icick'k'kif'k Program Starting word

1501 1 DO

AXIS. DEFAULTS NORMAL. DISPLAY SCREEN. CLEAR INTEN.ON INVERSE. ON

." T-M-P Group - Interactive Analysis Program "

INTEN.OFF INVERSE. OFF

CR CR

." Analyse file (Engineering S - e HIT 1

"

CR CR

." Produce table HIT 2

"

CR CR

." Plot data (Engineering S - e) HIT 3

"

CR CR

." Plot data (True Sigma -Epsilon) HIT 4

”

CR CR

Acquisition (NAR) HIT 5

"

CR CR

." Convert ASYST data file to ASCII (create *******. DAT) HIT 0

»

CR CR

." QUIT HIT S

"

CR CR KEY

CASE

49 OF READ. FILE CALCULATE . STRESS . STRAIN SEE.CURVEl

SPECIAL. POINTS SAVE. DATA ENDOF

50 OF TABLES GO. ON ENDOF

51 OF READ. FILE CALCULATE . STRESS . STRAIN PLOT. DATA ENDOF

52 OF READ. FILE CALCULATE . STRESS . STRAIN A PLOT.DATAl ENDOF

53 OF NAR ENDOF

48 OF READ. FILE CALCULATE . STRESS . STRAIN A CONVERT . TO .ASCII 1 ENDOF

83 OF LEAVE ENDOF

115 OF LEAVE ENDOF

NOP

ENDCASE

LOOP

9

92
S T-114A

I V. 3-89)

U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

1 .

2.

PUBLICATION OR REPORT NUMBER

NISTIR 89-3925

PERFORMING ORGANIZATION REPORT NUMBER

BIBLIOGRAPHIC DATA SHEET

riTLE AND SUBTITLE

PUBUCATION DATE

October 1989

DEVELOPMENT OF A COMPUTER-CONTROLLED HOT-DEFORMATION APPARATUS AT NIST

" VUTHOR(S) ~~

Yi-Wen Cheng, Yair Rosenthal, Harry I. McHenry

. i >ERFORMING ORGANIZATION (IF JOINT OR OTHER THAN NIST, SEE INSTRUCTIONS)

J.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

3AITHERSBURG, MD 20899

1 SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (STREET, CITY, STATE, ZIP)

7.

8.

CONTRACT/GRANT NUMBER

TYPE OF REPORT AND PERIOD COVERED

SUPPLEMENTARY NOTES

DOCUMENT DESCRIBES A COMPUTER PROGRAM; SF-185, FIPS SOFTWARE SUMMARY, IS ATTACHED.

ABSTRACT (A 200-WORD OR LESS FACTUAL SUMMARY OF MOST SIGNIFICANT INFORMATION.

.ITERATURE SURVEY, MENTION IT HERE.)

IF DOCUMENT INCLUDES A SIGNIFICANT BIBUOGRAPHY OR

his report describes a computer—controlled hot—deformation apparatus suitable for

hermomechanical-processing (TMP) simulation of forging and steel plates. The apparatus

las designed and built at the National Institute of Standards and Technology, and has the

i'ollowing main features: a servohydraulic load frame with a 250 kN capacity in tension or

ompression; a variable-actuator traveling speed up to 55 mm-s“l; a multiple-strike

apability with controllable displacements and strain rates; a maximum heating rate of

50°C-S“1 with a 10 kW induction heater (for a cylindrical steel specimen 9 mm in diameter

nd 18 mm in height): a maximum cooling rate of 25°C-s~^ with helium-gas cooling; and

acuum to 1,33 x 10 Pa (1 x 10 ^ Torr) within 25 min. Source codes of the computer

rograms that perform system control, data acquisition, and data analysis are included in

his report. The apparatus has been used to perform the direct-quenching simulation of

he ASTM A710 plate steel, and forging simulation of the directly cooled microalloyed

ISI 1522 and 1141 steels. Results of these studies are presented.

: KEY WORDS (6 TO 12 ENTRIES; ALPHABETICAL ORDER; CAPITALIZE ONLY PROPER NAMES; AND SEPARATE KEY WORDS BY SEMICOLONS)

Hi.lomputer control; continuous-cooling transformation; controlled rolling; direct quenching;

'orging; high-strength low-alloy steels; hot-deformation apparatus; microalloyed steels;

•hysical simulation; thermomechanical processing.

AVAILABILITY UNLIMITED

FOR OFFICIAL DISTRIBUTION. DO NOT RELEASE TO NATIONAL TECHNICAL INFORMATION SERVICE (NTIS).

14. NUMBER OF PRINTED PAGES

102

ORDER FROM SUPERINTENDENT OF DOCUMENTS, U.S. GOVERNMENT PRINTING OFFICE,

WASHINGTON, DC 20402.

15. PRICE

ORDER FROM NATIONAL TECHNICAL INFORMATION SERVICE (NTIS), SPRINGFIELD, VA 22161. CTRONIC FORM *U.S. GOVERNMENT PRINTING OFFICE: 19 8 9-0-773-845/25020

it*

V f