NBSIR 75-685

Improved Ultrasonic Standard

Reference Blocks

D. G. Eitzen, G. F. Sushinsky, and D. J. Chwirut

Engineering Mechanics Section

Mechanics Division

Institute for Basic Standards

and

C. J. Bechtoldt and A. W. Ruff

Microstructure Characterization Section

Metallurgy Division

Institute for Materials Research

National Bureau of Standards

Washington. D.C. 20234

April 1975

Interim Report for Period January 1, 1974 to December 31, 1974

Prepared for

Air Force Materials Laboratory

National Aeronautics and Space Administration and

Army Materials and Mechanics Research Center

NBSIR 75-685

IMPROVED ULTRASONIC STANDARD

REFERENCE BLOCKS

D. G. Eitzen, G. F. Sushinsky, and D. J. Chwirut

Engineering Mechanics Section

Mechanics Division

Institute for Basic Standards

and

C. J. Bechtoldt and A. W. Ruff

Microstructure Characterization Section

Metal lurgy Division

Institute for Materials Research

National Bureau of Standards

Washington, D.C. 20234

April 1975

Interim Report for Period January 1, 1974 to December 31, 1974

Prepared for

Air R)rce Materials Laboratory,

National Aeronautics and Space Administration, and

Army Materials and Mechanics Research Center

U S. DEPARTMEIMT OF COMMERCE. Rogers C.B. Morton. Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts. Director

CONTENTS

Page

1. INTRODUCTION 1

2. PROGRAM OUTLINE 3

3. ACTIVITY SUMMARY 5

3.1 Literature Survey 5

3.2 Ultrasonic Measurement Facility 6

3.2.1 Immersion System 7 3.2.2 Flaw Detection Equipment 7 3.2.3 Spectrum Analyzer 7 3.2.4 Accessory Equipment 8

3.3 Comparison of Nominally Identical Blocks 8

3.4 Metallurgical Considerations 10

3.4.1 Orientation Texture 10

3.4.2 Reference Block Microstructure 12

3.4.3 Ultrasonic Inspection of Rejected Block 13

3.5 Fabrication Considerations 14

3.6 Effects of Ultrasonic Measuring Systems 15

3.7 Single Material Standard 16

3.8 ASTM Participation 16

4. IMPORTANT CONCLUSIONS TO DATE 16

5. ACKNOWLEDGEMENTS 17

6. REFERENCES 18

Appendix A A-1

Appendix B B-1

Appendix C C-1

Appendix D D-1

Appendix E E-1

I
I
IMPROVED ULTRASONIC STANDARD REFERENCE BLOCKS

D. G. Eitzen, G. F. Sushinsky, and D. J. Chwirut

ABSTRACT

A program to improve the quality, reproducibility

and reliability of nondestructive testing through

the development of improved ASTM-type ultrasonic

reference standards is described. Reference blocks

of aluminum, steel, and titanium alloys are to

be considered. Equipment representing the stateof-the-art in laboratory and field ultrasonic equipment

was obtained and evaluated. RF and spectral data

on ten sets of ultrasonic reference blocks have

been taken as part of a task to quantify the variability

in response from nominally identical blocks. Techniques

for residual stress, preferred orientation, and

microstructural measurements were refined and

are applied to a reference block rejected by the

manufacturer during fabrication in order to evaluate

the effect of metallurgical condition on block

response. New fabrication techniques for reference

blocks are discussed and ASTM activities are summarized.

Key Words: Aluminum ultrasonic standards; ASTMtype reference blocks; fabrication of reference

blocks; immersion testing; longitudinal waves;

metallurgical variables; nondestructive testing;

pulse-echo; steel ultrasonic standards; titanium

ultrasonic standards; ultrasonics.

1. INTRODUCTION

In a wide range of technical activities, a greater dependence on nondestructive testing and evaluation (NDT and E) methods is being witnessed. The causes for this greater dependence on NDT and E methods

include increased structural performance requirements, the use of defectsensitive materials, changes in design philosophy, and increased requirements

for the determination of the condition and changes in the condition

of materials in service. The world-wide shortages of materials and energy

have created pressure for the adoption of a "keep it in service if possible"

attitude to replace the old "remove and replace on schedule" philosophy.

In particular, ultrasonic methods are being increasingly relied

upon to evaluate material and structural condition. Characteristically,

the NDT and E activities are performed at interfaces between different

operational groups, e,g., material supplier - user, subcontractor - contractor, and part production - assembly. Lack of agreement in the
results of ultrasonic evaluations at such interfaces can, in part, be

traced to a lack of standard methodology and a lack of basic measurement standards since the techniques are highly dependent on reference

standards. The incompatibility of measurements by different operational

groups results in uncertainties regarding the actual material condition.

These uncertainties lead to performance penalties due to increased design

uncertainties and either unnecessary piece rejection or inadequate service

performance. In addition to the performance penalties, serious economic

inequities often result from the lack of reference standards or measurement

inaccuracies.

A program to improve the widely used system of ASTM-type reference

blocks for longitudinal ultrasonic testing was started in January 1974.

The procedures for fabricating and checking these blocks are covered

in two ASTM documents, E 127-64 "Standard Recommended Practice for Fabricating

and Checking Aluminum Alloy Ultrasonic Standard Reference Blocks" [ij*,

and E 428-71, "Standard Recoiranended Practice for Fabrication and Control

of Steel Reference Blocks Used in Ultrasonic Inspection" [2j. Both of

these documents are widely referenced in government and industry purchasing

specifications and many other ASTM documents. One of the above documents

is also sometimes used as a guide for the fabrication of titanium alloy

ultrasonic reference blocks. However, both the authors and users of

these documents admit that both contain serious shortcomings, but, partly

because of corporate interests or priorities and a lack of institutional

mission, no one has produced acceptable improvements through the voluntary

standards systems. In fact, E 127 is scheduled to be dropped in January

1976 because it is unworkable in its present form yet no acceptable

alternative has been produced to date. A stop-gap alternative may be

approved later this year, but it is far from a total solution to the

probl em.

The ASTM-type reference blocks are cylindrical blocks with flatbottomed holes drilled along the block axis, see Figure I. A pulsed

stress wave produced by a piezoelectric transducer enters normal to

the undrilled end of the block and travels through the block. The flat

end of the drilled hole acts as a reflector and returns some of the

energy to the transducer which converts this energy into an electrical

signal. This reflected signal, displayed on a cathode ray tube (CRT),

becomes a reference signal for the evaluation of material of unknown

condition. Sets of reference blocks with different hole diameters and

different lengths are used to standardize ultrasonic measurement systems.

Measurements made with these systems then provide a basis for estimating

flaw severity and possible material rejection.

The problem with the reference blocks, simply stated, is this:

using a single ultrasonic measuring system, the ultrasonic response

^Figures in brackets indicate literature references at the end

of this paper.

2
£rom nominally identical reference blocks varies unacceptabl y . The ex- tent of this variation has been reported to be as great as 300 percent

in titanium. This causes, for example, different materials suppliers

and users to inspect to different levels of acceptability, resulting

in unjust competition between suppliers and increased costs due to un- necessary rejection and recycling (supplier over inspection) or wasted

transportation costs following user rejection (supplier under inspection).

The NBS program is intended to investigate systematically the ASTM-type

standard reference block system, to isolate if possible the causes of

the variability, and to develop a new system of standards that will

allow different organizations to make consistent measurements compatible

with each other. It is envisioned that the output from this program

could take one of three forms:

1) New methods documents to revise or replace ASTM E 127 and E

428 that would allow the NDT community to fabricate standard

reference blocks that introduce acceptably small variability

into the measurement system,

2) a system whereby certified standard reference blocks would

be fabricated, and sold by the National Bureau of Standards

through, for example, the Standard Reference Materials Program,

3) a calibration service whereby one set of blocks is defined

as THE STANDARD SET. Users' blocks could then be referenced

to this set following prescribed procedures.

This program is centered in the Mechanics and Metallurgy Divisions

of the National Bureau of Standards with consultation and support from

other Divisions where appropriate.

2. PROGRAM OUTLINE

The objective of the program is to affect near-term improvements

in the quality, reproducibility and reliability of ultrasonic nondestructive testing through the development of improved ASTM-type reference

blocks. The materials to be used for the development of standards include

aluminum, titanium and steel. The program is a two year effort to include

the following nine tasks:

Task I, Literature Search - A thorough search and review of all technical

literature regarding ultrasonic test standards will be conducted prior

to commencement of any major subsequent tasks. Results of the review

will be used where applicable to accelerate or modify subsequent tasks.

Task 2. Ultrasonic Measurement Facility - State-of-the-art ultrasonic

equipment and associated electronics appropriate for pulse-echo contact

and immersion evaluations will be obtained. This equipment will be

evaluated using current standardization methodology. This evaluation

will be performed with a view towards the establishment of standard

3
methods which are more definitive than those currently available. This

equipment is intended to form the core of an ultrasonic reference block

calibration facility, if established.

Task 3. Comparison of Nominally Identical Blocks - Nominally identical

blocks from commerical sources and from the field will be evaluated

for the distribution of ultrasonic response using the equipment of

task 2. This task will serve to assess the extent of variability of

ultrasonic responses from nominally identical blocks. The results of

this evaluation will have an effect on the methods used to Identify

the causes of the deviations in blocks.

Task 4. Metallurgical Considerations - The current state of knowledge

of the effects of the metallurgical conditions of materials on their

ultrasonic characteristics will be reviewed. A limited number of confirmation experiments will be performed. Additional tests on materials of

other metallurgical consistency will be undertaken to determine their

ultrasonic response characteristics. This knowledge will be applied

to the selection of materials for the fabrication of a master set of

ASTM-type ultrasonic reference blocks.

Task 5. Fabrication Considerations - A number of nominally identical

reference blocks with closely controlled metallurgical properties and

fabrication techniques will be obtained. The blocks will be closely

examined metrologically and the distribution of ultrasonic response

will be determined using the measurements laboratory of Task 2. Several

forming techniques will be used including the conventional drilling

technique, the use of raw stock formed by powder metallurgy, and the use of two-piece blocks. Comparison of the distributions in response

of these blocks with the results of the evaluation of nominally identical

field blocks (Task 3) will indicate whether significant reductions

in the deviation of ultrasonic response of blocks can be anticipated

in the near-term.

Task 6. Effects of Ultrasonic Measuring Systems - The results of previous round-robins on ASTM-type reference blocks will be checked to

determine whether different ultrasonic measuring systems obtain the same ranking and distribution of ultrasonic response from nominally

identical blocks. An additional round-robin will be performed, if ne- cessary. The cooperation of interested t<IDT users will be sought. The

verification of the principle of standardization associated with this

task is a necessary step toward the establishment of a rational calibration program.

Task 7. Master Reference Blocks - The results of the above tasks will

be used to develop master ASTM-type reference standards for aluminum,

• steel, and titanium. The final alloy selections for the master standards

will be based on metallurgical considerations, long-term availability,

ultrasonic response, incidence of structural use, and in consultation

with the sponsors.

4
Task 8. A Single-Material Standard - An effort will be made to establish

the feasibility of an improved standards program through the use of

a single-material master standard. A candidate for the single-material

standard is considered to be blocks made of crown glass. This material

can be controlled to have an impedance matching that of aluminum, has

no crystalline structure, has a minimal defect count (which can be

evaluated by light-scattering techniques), and is amenable to the most

sophisticated metrological evaluation. Preliminary analyses and tests

will establish the feasibility of a one-material standard as the basis

for determining the ultrasonic response of reference blocks of various

materials. Based on appropriate feasibility indications the development

of a basic standard will be considered. Future work may then be proposed

in order to establish this standard.

Task 9. Calibration Service - An ASTM-type reference block calibration

service will be initiated if appropriate. A system will be established

to quantify the responses of blocks in terms of the NBS master standards,

thus providing a coiranon basis for comparison and an objective evaluation.

Blocks will be evaluated in terms of the Master Reference Blocks of

Task 7. It is expected that any continuing calibration service will

be self-supporting through fees collected from the users.

The estimated program timetable is as shown in Figure 2.

3. ACTIVITY SUMMARY

3.1 Literature Survey

An extensive search and review of the open literature regarding

ultrasonic reference standards has resulted in a collection of over

two hundred documents. The search has included four areas: General

background information, ultrasonic measurement techniques, previous

work directly on standards, and the relationship of metallurgical variables to ultrasonic response. Formal inputs to the search were received

from:

Nondestructive Testing Information and Analysis Center,

Defense Documentation Center,

National Technical Information Service, and

Smithsonian Science Information Exchange.

Of these the input from NTIAC was the most comprehensive. The number

of pieces of open literature requiring review was surprisingly large,

but few speak directly and conclusively to the problem.

In addition to the open literature, several dozen private documents or corranuni cat ions have been analyzed. The search for unpublished

or private communications has been more time consuming but often more

substantive. Important information regarding ultrasonic reference standards

has been obtained through exchanges with representatives from such

5
organizations as Automation Industries, Krautkramer-Branson Inc., Reynolds

Metal s Company, Aluminum Company of America, Westinghouse Electric

Corporation, Kaiser Aluminum Company, Air Force Materials Laboratory,

Army Materials and Mechanics Research Center, Naval Research Labs,

Titanium Metals Corporation, Boeing Airplane Company, Douglas Aircraft

Co., General Dynamics, Grumman Aerospace Corp., The United Kingdom's

Aeronautical Quality Assurance Directorate Labs and Atomic Energy Research

Establishment Harwell Labs, and of course the American Society for

Testing and Materials.

A conclusion as to what is the major cause(s) of the wide distribution of response from nominally identical blocks when examined with

a given ultrasonic system was an important objective of the literature

search. No conclusion could be drawn. There were significant but sometimes

contradictory statements indicating material or metallurgical, dimensional

and fabrication problems. Apparently this question will not be resolved

until studies based on the results of Task 3 are completed. The review

of previous and ongoing work did result in several, more positive conclusions.

From work in the United Kingdom over the last ten years it is concluded

that "calibrations" by a corrected comparison with a standard set of

aluminum blocks can be made to within 1 dB, using state-of-the-art

equipment, and that sufficient reductions in block disparity to the

point where corrections are not required will be difficult [3j. From

work at Grumman [4j on reference blocks for titanium it is concluded

that two piece blocks may provide improved standards for this material.

From communications concerning work at Westinghouse and Automation

Industries, there is a large disagreement about the size of the problem

with steel reference blocks. An additional, important conclusion is

that the most active concentrated help can be expected from members

of ASTM committee E-7.06. The aluminum producers have been particularly

cooperative thus far.

3.2 Ultrasonic Measurement Facility

Commercially available, state-of-the-art ultrasonic equipment

and accessories suitable for contact and immersion testing have been

assembled through loans, through purchases with project funds and through

the availability of NBS equipment for the project. This includes an immersion tank with a motorized scanning bridge and precision manipulator,

flaw detection equipment with associated gating and amplifying circuitry,

a spectrum analyzer, and other accessory equipment. The laboratory

set-up is shown in Figure 3. Brief descriptions of this equipment are included below with more detailed specifications and characteristics

given in Appendix A.

6
3.2.1 Immersion System

The immersion system consists of a tank with transparent walls

and dimensions of approximately 38x21x18 in (97x53x46 cm)*. It is equipped

with a motorized bridge and carriage, search tube, motorized manipulator,

and mini-manipulator. It provides precision control of search unit

positioning in the X,Y and Z directions, as well as angular positioning

in two vertical planes normal to the tank bottom. A dry paper X-Y re- corder is provided.

3.2.2 Flaw Detection Equipment

Two field inspection type flaw detection units, on loan from AFML

and NRL are currently available for use in the laboratory. These units

feature a tuned, narrow band pulser and receiver combination. Their

nominal operating frequencies are l.O, 2.25, 5.0, and 10.0 MHz. A video

(as opposed to RF) presentation on the CRT is featured. Gating and

amplifying modules have also been borrowed, A third unit with updated

features is on order. In addition to the above features, this third

unit has a "calibrated" dB sensitivity control, an improved CRT display

and improved gating and amplifying circuitry. These units are suitable

for checking ultrasonic reference blocks per ASTM "Standard Recommended

Practice for Fabricating and Checking Aluminum Alloy Ultrasonic Standard

Reference Blocks" [ij.

A flaw detector suitable for collecting more detailed laboratory

data was also acquired. This unit consists of a power supply-frame,

and a broadband pulser receiver combination, stepless gate, and peak

detection and quantizing modules. Ultrasonic RF signals are displayed

on a 100 MHz bandwidth storage oscilloscope equipped with two wideband amplifiers. The stepless gate, peak detector, and quantizer provide

much of the necessary electronic signal processing for quantitative

flaw and search unit characterization. Signals are routed from the

receiver through the stepless gate where signals reflected from discontinuities

other than the one of interest are eliminated from the repetitive pulse

train and the desired wave packet is isolated. This signal can then

be used for spectrum analysis or further processed by the peak detector

and quantizer. The peak detector converts the positive peak amplitude

of the signal to a proportional DC voltage. This can then be quantized

into discrete DC voltages based on incremental signal amplitude changes.

Such processing is suitable for beam profiling, attenuation measurements

or gray-tone C-scan recordings.

3.2.3 Spectrum Analyzer

Spectrum analysis is performed on ultrasonic signals received

by the transducer after being processed through the gate circuitry.

*Units for physical quantities in this paper are given in both

the U. S. Customary Units and the International System Units (SI),

7
Signals analyzed are those reflected from special targets (e.g. steel

balls, flat quartz blocks) or defects. This information is necessary

for the evaluation of search unit characteristics and potentially helpful in determining defect size and orientation [5, 6j. In this program

the information will be applied to the determination of the size and

orientation of flat bottomed holes in reference blocks. The spectrum

analyzer consists of a storage CRT display, and separate IF and RF

plug-in modules. The frequency range extends from 0 to 110 MHz with

both logarithmic and linear sensitivity displays. Signals processed

through the stepless gate can be monitored for spectral content using

this instrument.

3.2.4 Accessory Equipment

Search units for use in contact and immersion longitudinal pulseecho testing made by three different manufacturers have been obtained.

The units were chosen on the basis of crystal diameter and nominal

center frequency to cover a representative range of those used in ultrasonic work. Special emphasis was placed on obtaining a few quartz search

units suitable for work on standard artifacts in accordance with ASTM

E 127 [ij and on units from which to choose for Task 3.

Seven sets of ultrasonic reference standards have been purchased

from three different manufacturers. These consist of three "Distance/Area

Amplitude" sets (basic sets), purchased directly from the Defense Supply

Agency (the source of most Air Force field blocks) and four "Distance

Amplitude" sets. The "Distance Amplitude" sets consist of 2 sets of

"number 3"* blocks from the same manufacturer and one set each of "number

5 and 8" blocks from the third supplier. This sample will provide a measure of the inconsistency of products manufactured by different

producers as well as the variability of the standards produced by the same manufacturer. These sets constitute part of the data base to be

established at this laboratory. In addition they provide convenient

working standards for activities in the program such as the evaluation

of new fabrication techniques and consistency checks when different

transducers are used.

3.3 Comparison of Nominally Identical Blocks

An important step toward decreasing the disparity in the ASTMtype ultrasonic reference blocks is a survey of nominally identical

blocks. The purpose of the survey is to quantify the extent of variability

in field blocks presently being used by the NDT community. Participation

was enlisted from the membership of ASTM E-07.06, the ultrasonics subcommittee, and from the general NDT community through an appeal in

*These reference standards are commonly referred to as "number

x" blocks where x represents the diameter of the "flat bottomed hole

in 64 THS of an inch (I in = 2.54 era)."

8
the Nondestructive Testing Information and Analysis Center Newsletter.

A list of organizations which have formally offered the loan of reference

blocks for data gathering purposes is presented in Appendix B. Five

borrowed sets of aluminum blocks have been inspected to date. Additional

blocks, aluminum, titanium and steel, have been scheduled. In addition

five sets of purchased blocks, 2 distance amplitude sets from one manufacturer and three basic sets from another manufacturer (through the Defense

Supply Agency) have been evaluated. Pulse-echo ultrasonic response

data were taken from the blocks at three test frequencies, 2.25, 5 and 10 MHz, using the immersion tank with temperature controlled distilled water, wide-band pul ser/recei ver , stepless gate, oscilloscope

and spectrum analyzer previously described. The ultrasonic measurement

system, was used only in its linear range as determined from the response

from steel balls. Some characteristics of the search units used for

the data are given in Table 1. All search units on hand at the start

of data taking were checked for symmetry, location of the point

(point of separation of near and far fields) [7j, center frequency

and frequency envelope, RF waveform and sensitivity. The search units

used to gather the reference block data were selected on the basis

of the above factors.

In taking the data on the blocks, all pul ser/recei ver settings

were put at a repeatable position. The gain was set using the reflected

signal from a selected steel ball positioned and maximized at the measured

point. The standardization points for the particular test conditions

are given in Table 2. The standardization points served only as a basis

for comparison of blocks with a given hole size and were chosen to

give the response nearest to the block with a 0.50 in (13 ram) metal

travel distance from the first set tested. After the pul ser/receiver

settings were selected, the transducer was positioned so that the Yq

point was at the ultrasound entry surface of the block. Then the return

signal from this surface was maximized by angulating the tranducer.

The oscilloscope time delay was used to expand the signal reflected

from the hole bottom. This signal was tapped off to the stepless gate,

which can be set so that the output from this module contains only

the signal of interest. Thus, only the return signal from the flatbottomed hole is fed into the spectrum analyzer. The data collected

for each block includes photo-recordings of the RF waveform and the

spectrum of the signal from the hole bottom, and a recording of 'the

peak-to-peak voltage and all pertinent equipment settings. Since only

one of the ten sets of blocks evaluated was an Area-Amplitude set,

the peak-to-peak voltage data is plotted against metal travel distance

for number 3, 5, and 8 hole sizes at each of the three frequencies.

Figures 4-12. Figure 13 presents typical photo-recordings of the RF

signal and the signal spectrum.

As can be seen from Figures 4-12, several anomalies were noted

in this study. The unserial -numbered set of number 5 blocks (Figures

5, 8, 11) give very inconsistent response, and in fact the response

increases with increasing metal distance at 5 and 10 MHz with differences

between nominally identical blocks that are in excess of 700%. The

blocks in set B-0109 appear to give consistently higher response than

9
blocks in other sets, with differences as high as 200% (Figure 12).

It appears that several widely variant blocks will be available for

inspection under tasks 4 and 5, in order to determine the actual causes

of the variability. One might conjecture, however, that at least a part of the disparity is due to a material condition since one might

expect more random variances from the mean to result from other suspected

variables such as improper geometry.

* 3.4 Metallurgical Considerations

This task is concerned with the evaluation of the distribution

in response of ultrasonic reference blocks and the material from which

they are fabricated, particularly in connection with metallurgical

and microstructural parameters. The emphasis has been on aluminum

alloys so far, however, titanium has been examined briefly and will

be studied further in the next year. Some emphasis will also be placed

on steel. An aluminum reference block rejected by the manufacturer

during fabrication is currently under close examination. Correlations

are being sought between ultrasonic response anomalies and microstructural

features. Techniques for residual stress measurements, preferred orientation measurements and microstructural measurements have been refined

and are being applied in this task.

3.4,1 Orientation Texture

Measurements of preferred orientation textures have been conducted

as part of this study in order to determine the degree of nonrandoraness

and variability present in relevant specimens. A brief description

of the texture measurement process is as follows. The data-collecting

X-ray scaler has a memory which permits the accumulation of new diffraction data while the previous collection is transferred to punched tape.

The pole figure device operates in the spiral mode (reflection method)

which involves the rotation of the sample in its plane (alpha angle)

every 16 minutes while moving off the center 5** (beta angle).

Computer programs in BASIC language were written to manipulate

the diffraction data gathered using the pole figure device on the diffractometer. The programs developed for the data analysis and plotting

(called Poleft) are included as Appendix C and are annotated. The Xray data were corrected for background and the strongest point assigned

a value of 100. A Fourier series was fitted to the data points in groups

and the beta angle then interpolated for each intensity value from

10 to 90 at intervals of 10. The program contains an algorithm which

converts the polar coordinates to cartesian coordinates for plotting

the pole figure. This data is written into a computer file which is

utilized by a program called Polepl (see Appendix D) to plot the pole

figure on a stereographic projection. An automatic X-Y plotter which

permits conversational interaction during plotting was used.

Studies have been conducted on several aluminum alloy and titanium

specimens cut from sheet stock. These specimens were used for technique

10
development and to determine the range of measured variables. Two pole

figures made from a specimen cut from an aluminum sheet, 7075-T631, are shown. The (200) pole figure, Figure 14, indicates a maximum intensity

(density of poles) in the center, falling off less rapidly in the direction

of rolling than in the transverse direction. A random orientation of

grains in the satiple would lead to a uniform pole figure having a constant

intensity level. In this case a tendency is present for grain orientations such that (200) planes in those grains are parallel to the sheet

surface. The maximum pole density (100 relative units) lies in the

center corresponding to the normal to the sample surface. The (111)

pole figure for this specimen. Figure 15, shows a secondary maximum

(50 units) in the center but the maximum intensities are at about 55°

from the center in the transverse direction. This value is the angular

distance between the (100) and (111) planes; the two pole figures are consistent with each other. This aluminum alloy sheet, therefore, shows

a strong preferred orientation.

Pole figure determinations were made on several titanium sheets.

A (10.1) pole figure made on a 507o reduced sheet is shown in Figure

16. The pole figure shows a four-fold symmetry with the maximum intensities occurring at about 35° from the center. Texture measurements

were also made of the same sheet in the annealed condition, 1355 *F

(73 5 **C), 5 min. The maximum intensity in the (00.2) pole figure, Figure

17, occurred in the center. In the (10.1) pole figure. Figure 18, the

maximum occurred at about 50" from the center. Comparison of Figures

16 and 18 indicates the strong differences in texture that can be expected

in titanium as a result of different mechanical and thermal treatments.

X-ray diffraction measurements were taken from one surface of

the slice (see Figure 22) sectioned from the rejected aluminum ultra- . sonic reference block. The pole figures corresponding to reflections

(200), (111), and (220) are included with this report. The axis of

the block is located at the center of these pole figures. The (200)

pole figure, Figure 19, shows two-fold symmetry with the maximum intensity in the center. The intensity falls off to less than 10 units

at a deviation of 5 degrees from the axis. Secondary maxima of 40 are located at 180 degrees to each other at a deviation from the axis of

approximately 25 degrees. The relatively high intensities of the (200)

poles at the axis of the slice imply a high density of (200) poles on the cylindrical surface of the block. This axial orientation texture is very strong as indicated by the rapid decrease in pole density

within 5 degrees of the axis.

The (111) pole figure, Figure 20, shows maxima at 35 and 55 degrees

from the axial position. These maxima- would be expected at these locations on the basis of the (200) pole figure. The (111) pole density at 55

degrees from the center shows psuedo four-fold symmetry indicating

that the (200) preferred orientation in the center has a secondary

preferred orientation and is not distributed randomly about the axial

position. This preferred orientation of the (111) poles has also been

noted in the residual stress measurements since the intensities of

11
peaks measured at other than zero inclination angle are fouad to vary

with the rotation of specimens. The (222) peak is used with other diffraction peaks in obtaining the residual stress data.

The principal feature of the (220) pole figure, Figure 21, is

the occurrence of maxima in restricted belts about 22.5 degrees from

the center of the figure. These must be related to the (200) poles

which reach secondary maxima in two large areas about 22.5 degrees

from the center of the (200) pole figure. Secondary maxima of the (200)

poles occur at 45 degrees and have four-fold symmetry. These are related

to the very sharp maximum occurring in the center of the (200) pole

figure.

This pole figure Information suggests that this reference block

has secondary preferred orientation around its axis. The texture must

have occurred from early fabrication of the rod. Since ultrasonic attenuation is sensitive to crystal orientation in stressed crystals,

then this texture may be contributing significantly to the ultrasonic

response of the block. Variations, if any, of the texture throughout

the block will be sought.

There is some scatter in the center of the pole figures which

is due to grain size. Even with 0.6 in (15 mm) oscillation of the specimen during X-ray measurements, the scatter is largest at low beta angles

but disappears when the beta angle has passed 20 to 25 degrees. At

increasing beta angle for the same slits, a larger area of the specimen

is covered by the X-ray beam. This effect may also be due to the grain

shape, that is, the diffracting planes examined may have spread out

further parallel to the surface of the specimen than in other directions

if the grains are elongated in the surface plane.

3.4.2 Reference Block Microstructure

The aluminum reference block rejected by the manufacturer after

fabrication was sectioned after preliminary acoustic inspection in order

to examine the uniformity of metallurgical microstructure throughout

the block. As indicated in Figure 22, the block was sectioned into three

principal parts. The end containing the flat-bottomed hole was cut off

at a length of 1.2 in (30 mm) and subsequently, a slice 0.16 in (4 mm)

thick was taken from the surface opposite the flat-bottomed hole for

texture measurements. The remaining block, 2.4 in (61 mm) long, was examined ul trasonical ly and then sectioned into two portions, each 1.2

in (30 mm) long. These two portions were ul trasonical ly inspected in

detail. All cuts were carefully made perpendicular to the axis using

a narrow, thin circular saw blade. The newly cut surfaces were then

metallographically polished using a series of progressively finer abrasives,

finishing with 40 pin (1 ym) diamond followed by MgO powder. Care was

taken to minimize deviations from a flat surface and rounding at the

edges . ;

Two of these new surfaces were examined metallographically. Several

etching solutions were used. The results did not differ substantially.

12
Figure 23 is an optical micrograph of an as-polished surface (S2). Many

voids and cavities are seen there. Etching the polished surface reveals

the grain structure and other phases that are present in this alloy,

Figure 24. The grain diameters generally are in the range from 4 to

20x10 ^ in (10 ym to 50 ym). At longer etching times another feature

emerges in many of the grains as shown in Figure 25, "Star-like" features

appear within the grains and are probably due to composition variations

arising from solidification structures that remain from the initial

ingot stage. This surface (S2) was lightly polished mechanically and

reexamined without further etching. Figure 26 shows the remaining grain

boundary outlines and _many examples of voids and second phase regions

in the alloy. At higher magnification, details can be seen in several

of the second phase regions marked as A in Figure 27, The discrete

pitting reactions at the grain boundaries (rather than continuous, uniform

etching) suggest that discrete precipitates lie along the boundaries

in nonuniform distributions.

The microstructure seen on the section surfaces is believed typical

of the entire block. It is complex and nonuniform, containing many voids,

cavities, foreign phase regions, and possible inclusions. Some original

solidification structure remains, including possible alloy composition

gradients. These structures would be expected to affect ultrasonic wave propogation and the lack of homogeneity in structure would produce non- uniform ultrasonic response. Studies of other reference block specimens

should be conducted to determine how frequently such nonuniform structures

are found,

3.4.3 Ultrasonic Inspection of Rejected Block

The two 1,2 in (30 mm) blocks were inspected ul trasonical ly. They were scanned using a nominal 10 hffiz longitudinal beam transducer in an immersion tank. Each was first scanned such that the area between

the top surface of the block and the bottom surface was displayed. No

acoustic anomalies were observed on these scans. It was suspected that

the material was not uniformly attenuating. Therefore, a delayed presentation of the amplitude of the first back reflection was observed

as the block was scanned. Water path distance was maintained at 3,0

in (7.6 cm), during the scanning operation. Scanning increments were

set at 0,030 in (0,076 cm). Seventy-five scans were needed to traverse

the 2 in (5 cm) blocks because of transducer beam spreading. Each block

was scanned in two orthogonal directions. An arbitrary amplitude of

+60 mV was chosen as the norm in checking for attentuation uniformity.

Amplitude losses greater than 1/3, i,e., signals less than +40 mV were

noted at several locations.

Signal amplitude increases ( > 60 mV) were also noted, particularly

on block 1, Figure 22. Waveform and spectrum photographs (Figures 28

and 29 respectively) were taken at particular locations using the techniques described in Section 3.3. Further Information is given in Table

3. Using a nominal 5 MHz search unit, amplitude losses were less than

157o and no location information was quantified.

13
3,4,4 Residual Stress Measurements

The stress measurements were made using the method outlined in

SAE TR-182, "Measurement of Stress by X-rays", [8], However, the determination of the peak position is done differently. The alpha-1 peak

is separated by using a modified method of that outlined by Gangulee

[9j in the separation of ot^ - doublets. The new points near the center

are fitted to a parabola and the parabola maximum is taken as the peak

position. The annotated program used to calculate the stress is included

as Appendix E. ,

The residual stress results from the sectioned block surfaces are summarized in Figure 22 and are shown in more detail in Appendix E.

The first results were obtained by fitting a parabola to five equally

spaced points. The measurements were made using the 222 diffraction

indices using chromium radiation. The intensity of the peaks varied

with the angle of inclination and with rotation of the specimen. The

reason for this effect is quite evident in view of the texture shown

in the (111) pole figure, Figure 20. The texture caused some problems,

especially at the 15* angle of inclination, in getting useful data.

It is felt that separation of the doublets will give better results

in the interpretation of data with widely varying intensities. There

seems to be a significant variation in residual stress measured on sec- tioned surfaces of this block. Further investigation of additional surfaces,

of the effect of surface preparation, and of other materials is indicated.

3.5 Fabrication Considerations

Two areas related to the physical (non-metallurgical) fabrication

of reference blocks are being studied. The first is a study of the critical

dimensions in E 127 blocks. Arrangements have been made with the Dimensional

Technology Section at NBS to inspect selected blocks for hole diameter,

hole depth, surface finish of the hole bottom, parallelism of the hole

bottom and top surface, and corner radius. Blocks tested in Task 3 that

exhibit anomalous response and are available for destruction will be

tested for anomalous physical dimensions. Further work in this area

is deferred pending further progress on Task 3. In a related experiment,

eighteen No. 5 blocks, six each with 0.50, 3.00 and 5.75 in (12.7, 76.2,

and 146.0 mm) metal travel distance were machined at NBS with the E

12764 tolerances specified. The material was 7075-T651 aluminum alloy,

of unknown origin, except that it was all from one heat. This temper was used because a supply of material from one heat was readily available,

and hopefully metallurgical variables could be minimized. After the

cylinders were machined, but before the flat-bottomed holes were drilled,

the cylinders were inspected ul trasonical ly at 5 MHz to determine material

uniformity. Among sets of nominally identical blocks, the back surface

response along the cylinder centerline varied by no more than 10 percent

among the six blocks. After the flat-bottomed holes were drilled, the

blocks were cleaned and plugged temporarily per E 127, and inspected

ul trasonically at 2.25, 5.0, 10.0, and 15.0 bfilz. The results of these

tests are given in Table 4, At 5 MHz, the scatter between similar blocks

14
was always Less than +7 percent, most of which is attributed to material

nonuni formi ty , At 2,25 MHz, the scatter is even less, but at 10 and

15 MHz it is somewhat greater. It therefore appears that, at least in

this case, the machining of the flat-bottomed holes did not introduce

significant disparity into the measurements. Dimensional metrology will

be used to determine if the dimensions of these blocks are significantly

more uniform than required by the tolerances as specified in ASTM E

127. Blocks with No. 3 and 8 holes will be similarly fabricated and

checked.

A second subtaskrelatlng to fabrication is a feasibility study

of making two piece blocks. If it is determined that inaccuracies in

the dimensions of the flat-bottomed hole are a cause of ultrasonic variability, it may be beneficial to fabricate the reference block from

two cylinders, one solid and one containing a through hole. This would

greatly facilitate both the machining and metrology processes. The two

cylinders would then be connected by an ultrasound-transmitting bond,

such as wringing or diffusion bonding. The latter has been reported

to be feasible for titanium, e.g. ['^j, but as yet no work on this has

been done on the current program. Some experiments have been performed

on wrung pieces of steel, aluminum, and quartz, the latter with a view

toward Task 8. Test pieces with very flat surfaces (0.5 fringe or better)

and very fine surface finishes (2 pin or better) were fabricated and

wrung together using dimensional gage block techniques. Ultrasonic data was taken at 5 MHz, and in some cases in the steel and quartz, the re- flected energy received from the interface was less than 10 percent

of that received from the back surface. No success has been achieved

with the aluminum. This work will be continued or dropped, depending

on whether or not hole geometry is found to be a significant cause of

variabil ity

3.6 Effects of Ultrasonic Measuring Systems

Using current standardization procedures, consistent quantitative

measurements from various systems are not possible unless the ratio

of responses from two references is, the same on both systems. For example, an area-amplitude set of blocks that is linear on the block manufacturer's

system must also be linear on the user's system in order to be useful.

To determine what effects different test instruments have on the relative

response of aluminum blocks, an intercomparison of data was made between

NBS and the Reynolds Metals Company. Data was taken on three distanceamplitude sets using the same 5 MHz, 0.375 in (9.5 mm) diameter quartz

search unit and the same test procedures, but with different instruments,

although the same model.

The data from the two labs are presented in Table 5. The variability

between systems, including operator error, is in general less than 10

percent.

In addition, three runs were made at NBS on one set of blocks using

the same test system but with different operators in an attempt to quantify

15
operator error. This data is given in Table 6. The maximum deviation

between readings was less than 5 percent of the average of three readings

except for one point down to the values where the minimum resolvable

increment was greater than 5 percent of the reading.

3,7 Single Material Standard

The feasibility of using a material with no grain structure, high

homogeneity and good inspectabil i ty such as fused quartz or crown glass,

as a single material standard is being considered. This idea was well

received by the attendees at the NBS NDE Public Review and Workshop

in December 1974. This approach might require the development of transforms

relating the acoustic impedance, attenuation, and sound speeds of the

master blocks and structural materials. Significant effort on this task

is planned.

; 3.8 ASTM Participation

The NBS investigators have joined and become active in ASTM Committee

E-7 on Nondestructive Testing, Sub Committee E-7.06 on Ultrasonics,

and particulary section E-7. 06. 02 on Aluminum Reference Blocks. Close

contact has been maintained with the chairman of E-7. 06. 02 and considerable

consultation has taken place regarding the revision of E 127 scheduled

for ballot by E-7.06 and E-7 later this year. Experiments were performed

to verify the validity of using a universal distance-amplitude curve

to replace the three curves currently used (Figure 6 of [ij). If different

standardization points are used for different size blocks, their responses

can be compared to a single curve of higher amplitude than the number

3 and number 5 curves in the current document. In the current document,

the maximum response expected from a number 3 hole is only 12 percent

of the scope vertical linear limit, and resolution becomes a problem.

The data from three sets of blocks, one each No. 3, 5, and 8, when plotted

on a universal distance-amplitude curve basis, are shown in Figure 30.

The scatter between these data appears to be no worse than the scatter

between data from blocks of the same size (Figures 4-12). Continued,

long-term participation in activities of these groups is planned.

4. IMPORTANT CONCLUSIONS TO DATE

Based on the work completed to January 1975 the following conclusions

are drawn:

1 ) No previous work has isolated the cause of block variability.

The problems of dimensional, metallurgical and fabrication

; considerations must all be attacked. Work in the United

Kingdom has suggested it would be difficult to fabricate

blocks with less than ± 1 db variability but that this tol- erance can be achieved with assigned correction factors

("calibration").

16
2) Among the blocks evaluated to date, the "average" variation

between nominally identical aluminum blocks is about 20-

30 percent, hut variations as high as 700 percent have

been recorded.

3) Metallurgical studies were conducted on an aluminum block

rejected by the manufacturer during fabrication. The block

contained a high degree of preferred orientation texture,

probably occurring as a result of the fabrication processing

of the rod from which the block was made. The block microstructure was complex; voids, second phase regions and

chemical concentration variations were all present. Significant variations in residual stress in this block were

also found. All these factors probably contribute to the

measured variation from -50 to 25 percent around the average

back surface ultrasonic response of this block.

4) Efforts to manufacture two-piece blocks wrung together

have met with mixed success. Some success has been achieved

with steel and quartz, little with aluminum. One-piece

aluminum blocks have been fabricated at NBS from a uniform

lot of material. The spread among six nominally identical

blocks was less than 10 percent for three different sets.

5) The variability between data taken by three operators using

the same blocks and the same equipment was measured to

be less than about 5 percent. The deviations between readings

from two operators using the same blocks and the same search

unit but different systems was less than 10 percent.

5. ACKNOWLEDGEMENTS

The following people have made helpful contributions to this program.

Their assistance is gratefully acknpwledged.

Gary D. Boswell and Robert G. Elmer, Engineering Mechanics Section,

NBS - laboratory assistance.

Martin Greenspan, Carl Tschiegg, and Frank Breckenridge , Sound

Section, NBS - consultation on equipment and transducers.

Carlton A. Burley and Dave Feitig, Reynolds Metals Company - technical consultation on testing procedures and ASTM E 127,

Michael A. Kearney, Automation Industries - consultation on equipment

and aluminum blocks.

17
In addition reference blocks have already been loaned by the following

companies for evaluation under task 3:

Naval Research Laboratory

Reynolds Metals Company

Westinghouse Electric Corporation

Wyman-Gordan Company

Sponsorship and financial assistance have been received from the

Air Force Materials Laboratory, National Aeronautics and Space Administration

(Lewis Research Center), and the Army Materials and Mechanics Research

Center. These organizations were technically represented by Lee R, Gulley,

Jr., Robert L. Davies,and George Darcy, respectively. The work was administered

through the Air Force Materials Laboratory with Lee R. Gulley, Jr. as project monitor.

6. REFERENCES

[ij Anon., Standard Recommended Practice for Fabricating and Checking

Aluminum Alloy Ultrasonic Standard Reference Blocks, ASTM Designation

E 127-64, 1974 Annual Book of ASTM Standards . Part 11 (Am Soc Test

Mat, Philadelphia, 1974).

[2j Anon., Standard Recommended Practice for Fabrication and Control

of Steel Reference Blocks Used in Ultrasonic Inspection, ASTM Designation E 428-71, 1974 Annual Book of ASTM Standards , Part 11 (Am Soc

Test Mat, Philadelphia, 1974).

[3j Millman, I., An Improved Facility for the Calibration of Aluminum

Alloy Ultrasonic Reference Blocks, Report No. AQD/NDT1369, AQD Labs,

Harefield, Uxbridge, Middlesex, U.K.

[4j Kettering, D.D., Nondestructive Testing Calibration Procedures,

Quality Control Lab. Report No. 027160. Gruimian Advanced Development Report.

[5j Chaskelis, H.H., Transducers-Fact and Fiction, Non-Destructive Testing,

p 375, December 1971.

[6] Reynolds, P.M. (editor). The Future of Ultrasonic Spectroscopy,

Proceedings, October 14, 1970.

[7j McElroy, J.T., Identification and Measurement of Ultrasonic Search

Unit Characteristics, Automation Industries, Inc. Research Division

TR 66-5, April 1966.

[Sj Christenson, A.L., Measurement of Stress by X-rays, Society of Automotive Engineers, Inc., TR-182 (1960), as corrected by errata sheet

dated March 11, 1964.

18
[9j Gangulee, A., Separation of the a - a Doublet in X-ray Profiles,

J. Appl. Cryst. 3, 272 (1970).

19

Table I - Characteristics of Ultrasonic Search Units

Nominal Center Crystal Measured

Frequency Diameter Point Transducer Type Serial No.

MHz in mm in mm

2.25 0.50 12.7 2.5 64 A306 3529

5.0 0.50 12.7 5.0 127 A309 3042

10.0 0.25 " 6.4 2.5 64 A312 4263
Table 2 - Standardization Points for Aluminum Blocks

Block

Hole Size

in mm

0.047(//3) 1.19

0.047 1.19

0.047 1.19

Test

Frequency

MHz

2.25

5.0

10.0

0.078(#5) 1.98

0.078 1.98

0.078 1.98

2.25

5.0

10.0

0.125(//8) 3.18

0.125 3.18

0.125 3.18

2.25

5.0

10.0

Ball

Diameter Amplitude

in mm

0.0625 1.588

0.1875 4.762

0.2812 7.144

1.20

1.20

0.60

0.1250 3.175

0.4375 11.112

0.6250 15.875

1.28

1.20

0.60

0.3125 7.938

1.0000 25.400

1.0625 26.988

1.20

1.20

0.58
Table 3 - Rejected Block Response

Block

Location

No.

Figure

No.

1 f ^ \ 9ft v.a; noriQcix area ^ou luv peaK^

1 (2) '28 (b) amplitude loss (36 mV peak)

in crosshatched area

40% loss

1 (3) 28 (c) amplitude gain (65 mV peak)

1 (A) 28 (d) amplitude gain (75 mV peak)

2 (1) 29 (a) "normal" area (60 mV peak)

2 (2) 29 (b) amplitude loss (30 mV peak)

in crosshatched area

50% loss

2 (3) 29 (c) amplitude loss (50 mV peak) 15% loss

uiptnent Settings:

Pulser /Receiver

Rep Rate: //3 Filter: 3 Voltage: (150; .1)

Damping: min.

Gain: 26.5

Spectrum analyzer

C.F. : B.W. : Atten:

Filter;

10 MHz

100 kHz

0

0

Gain: linear

ImV/div X .25
Table 4 - Ultrasonic Response of NBS Homemade 7075-T651 Blocks.

Ultrasonic Response, volts

Block. Size . Test Frequency, MHz

and Number 2.25 5.0 10.0 15.0

5-0050-1 1.00 1.00 0.500 0.300

-

^ ^2 ^ 1.02 1.00 0.530 0.320

-3 : 1.02 ; t 1.02 0.530 0.325

-4 1.02 ^ 1.02 0.530 0.315

-5 1.05 1.01 0.540 0.300

' -6 1.03 0.99 0.500 0.270

5-0300-1 : 1.19 0.450 0.500 0.245

-2 1.27 0.475 . : V; 0.550 0.305

-3 . 1.30 0.480 . 0.570 0.325

-4: 1.22 0.455 0.500 0.250

-5 1.20 0.425 0.470 0.225

-6 1.20 0.420 0.480 0.240

5-0575-1 '

' 1.32

-2 1.30

-3 .1.40

-4 1.34

, -5 . . ^ 1.40

-6 r 1.30

/
Table 5 - Results of Data Intercomparison on Ultrasonic Blocks. Search

Unit-5 MHz, 0.375 in quartz (SN 50A 1338) Water Distance = 3.5 inches.

Metal #3 Blocks //5 Blocks //8 Blocks

Distance Lab A Lab B Lab A Lab B Lab A Lab B

(Block)

STD PT-0050 100 100 100 100 100 100

-0075 83 80 8A 76 83 75

-0100 67 67 67 69 78 65

-0125 54 58 56 A8 58 54

-0175 37 40 38 33 45 38

-0225 27 25 30 24 33 25

-0275 20 23 20 21 22 19

-0325 16 17 16 15 18 16

-0375 12 13 14 15 15 12

-0425 11 10 11 11 12 9

-0475 9 9 10 9 10 8

-0525 8 7 8 6 10 6

-0575 7 5 7 6 9 6
Table 6 - Evaluation of Operator variability. Block set 150-3 (y/5 blocks),

5 MHz 0.375 in quartz search unit.

Spread Spread

Block

No. Operator A Operator B Operator C Ave.

Among

3 Runs

Avg.

%

5-0050 100 100 100 100

-0062 88 86 88 87.3 2 2.3

-0075 84 80 80 81.3 4 4.9

-0088 75 72 72 73 3 4.1

-0100 66 65 66 2 3.0

-0125 : 56 . 54 .. 55. 55 2 3.6

-0175 38 36 '-i 37 37 2 5.4

-0225 29 29 29.3 1 3.4

-0275 20 21 a. 21 20.7 1 4.8

-0325 r 16 - ^ 17. 16.3 1 6.1

-0375 'J:4.-;'./ 13 13 13.3 1 7.5

-OA25 11 11 11 11 0 0

-0475 10 ^ 9 9.7 1 10.3

-0525 7 8 7.7 1 13.0

-0575 . 7 . "; 6 7 6.7 1 14.9
Hole A , bottom must be flat within

0.001 per 0.125 dia., and finished

size must be the required dia. it 0.0005

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Hole must be straight and perpendicular

to entry surface within 0**-30' and

located within 0.010 of longitudinal axis

Back Surface

Flat Counterbore

0.250 X 0.062 deep AJT"Except as noted

Figure 1- ASTM E-127 ultrasonic standard reference block.

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Figure 23 - Optical micrograph of surface S2 as polished.

'9f

Figure 24 - Optical micrograph of surface S2 after first etching.
Figure 25 - Optical micrograph of surface S2 after longer etching.

Figure 26 - Optical micrograph of surface S2 after repollshing,
Figure 27 - Higher magnification optical micrograph of surface S2 after

repolishing.
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APPENDIX A

Equipment Specifications

Some of the important specifications for the equipment identified

in Section 3,2 are given below:

1. Ultrasonic Immersion System

a) Tank Dimensions:

b) Bridge and Carriage

Operating in the automatic scanning mode the bridge and carriage

assembly is controllable within the following limits:

(1) Bridge Indexing

- adjustable from 0.001 in (0.03 mm) to 0.099 in (2.5

ram) in 0,001 in (0.03 mm) increments.

(2) bridge travel

- at least 38 in (97 cm)

(3) carriage speed

- continuiously adjustable from approximately 0.5 in

(1 cm) to 15 in (38 cm) per second.

(4) carriage travel

- adjustable from approximately 4.0 in (10.2 cm) to 12

in (30 cm) in 0,5 in (1 cm) increments.

c) Motorized Manipulator and Search Tube

(1) vertical indexing

- adjustable from 0.001 in (0.03 mm) to 0.099 in (2.5

mm) in 0.001 in (0.03 mm) increments.

(2) vertical travel

d) Auxiliary Manipulator

This mini-manupulator provides angular adjustment in two right

angle vertical planes with tilt ranges of ±30 degrees. Uncertainty

is angular adjustments is less than 1 degree.

Length

Width

Depth

38 in

21 in

18 in

97 cm

53 cm

46 cm

- at least 17.0 in (43 cm).

A-1
e) X-Y Recorder

The X-Y recorder Is a dry paper type using electrosensitive

paper with an electrostatic paper hold down. The pen is mechanically

driven to provide approximately 1 to 1 recordings.

- platen size - 11 by 17 in (28 by 43 cm).

f) Temperature Control

An immersion heater with thermostatic control provides the capability

of maintaining temperature in the 70 °F to 80 "F (21 "C to 27 °C)

> range with a time variation of 1 °F (.05 °C).

g) Water System

An internal water system consisting of a pump, filter, and water

skimmer is provided.

Broadband Ultrasonic System

a) Pul ser/Receiver

(1 ) Pulser

- output voltage selectively variable from 40 to 350

V into 50 ohms.

; - rise time - 5 - 15 ns measured between 10 and 90

percent amplitude points.

- pulse width - 15 - 150 ns measured full width at

hal f ampl itude.

- frequency - 0 - 30 MHz.

- repetition rate - 500 to 5000 Hz internal oscillator;

0 to 10000 Hz external source.

- damping resistance - 5 to 500 ohms.

Typical pulses are shown in Figure A-1, These were taken at

the narrowest pulse width setting with minimum damping. Figure

A-1 represents the pulse used under normal operating procedures

documented in this work.

(2) Receiver

- frequency range - 0 to 30 Hiz

- input impedance - 500 ohms

- gain 10 to 70 dB

- voltage output - maximum 2.5 V peak-to-peak

b) Gate

- eliminates unwanted signals from a repetitive pulse

train to isolate the desired wave packet without

distorting the wave packet.

- delay range - 0.2 to 1000 ys.

- width range - 0.2 to 100 ys.

A2
- switching transients - less than 10 raV (see Figure

A-2 for measured transients).

- bandwidth - 0.2 to 50 MHz.

Several commerical ly available "stepless" gates were evaluated.

The unit chosen represents the most versatile gate with the

required specifications in gate delay, width and minimized

switching transients. Switching transients of those evaluated

typically ranged from less than 10 mV for the laboratory system

to 50 mV using an inexpensive double balanced mixer.

c) Peak Detector^

- converts the peak amplitude of ultrasonic pulses to

a proportionate EX^ voltage in both the linear and logarithmic mode.

- input range - 0.01 to 1.0 V positive.

- input pulse width - 20 ns minimum.

- linearity - ±5 percent of peak amplitude or ±2 mV at

input, whichever is greater.

- linear gain - adjustable from 0.5 to 16 times the input.

- logarithmic gain - adjustable from 40 to 1.25 dB full

scale.

- DC offset - 0 to 5 V or 0 to 40 dB.

- output voltage - 0 to 1 VDC into 1000 ohms.

- decay time - 0.01, 0.1, and 1 seconds.

d) Quantizer

- enables a step-wise quantization of gated video signals

into discrete DC voltages.

- input range - 0 to 10 V peak video signals.

- input pulse width - 200 ns minimum.

- quantization range - 5 to 80 increments into a total

range of 40 dB.

Spectrum Analyzer

The spectrum analyzer consists of a storage CRT with separate

IF and RF plug-in modules.

- frequency range - 0 to 110 bftlz with adjustable center

frequency.

- bandwidth - 0.01 to 300 kHz.

- scan width - 0.02 kHz to 10 MHz per division.

- scan time - 0.01 to 10 seconds per division.

- calibrated vertical reference level.

- log +10 to -72 dBm per division.

- linear 0.025 mV to 100 mV per division.
Search Units

Search units purchased for this work are listed in Table A1 by crystal diameter and nominal center frequency. Both immersion and contact types are included. These represent but

a sample of the available size-frequency combinations. Particular

emphasis has been placed on the 0,375 in (0.953 cm) quartz

crystal at 5.0 and 15.0 MHz in order to be compatible with

ASTM E 127 specifications of 1964 and proposed modifications,

as well as search unit size and frequency combinations suitable

for use in Task 3,


APPENDIX B

Organizations offering Loan of Reference Blocks

Aluminum Company of America

Battelle Memorial Institute

CBL Industries, Inc.

Curtiss-Wright Corporation

Kaiser Aluminum Company

Krautkramer-Branson, Inc.

LTV Aerospace Corporation

Met Lab Inc.

NASA, Lewis Research Center

Naval Research Labs

Naval Weapons Center

Pratt and Whitney Aircraft Company

Reynolds Metals Company

Westinghouse Electric Corporation

Wyman-Gordon Company

B-1

APPENDIX C

POLEFT Program

10 • PCLEFT REDUCES SCALER DATA OUTPUT FROM TEXTURE GONIOMETER

20 • FOH USED IN PLOTTING "POLE FIGURE BY POLEPL.

30 !###.## ####.## ####.## ####•## #### #### ####

40 :##.# ###.# ##•# ##.# ### ### #•### ##.# ##•# ##.# ### ### ###;

50 DIKYCl 5* 86) *C (200 )*D(500 ) > A ( 50 ) >B ( 50 ) > AS ( 72 ) * E$ ( 72 ) *BS ( 72

60 DIKI ( 100 )>X< 100 )>Z(100 )>Q (100 ) 70 PRINT"TYPE IN INPUT AND OUTPUT FILE NAMES";

80 INPUT CS>D$ • PERMITS DESIGNATION OF FILES AT RUN TIME.

90 IF C$="STOP" THEN 1240

100 FILES C$*D$

110 SCRATCH#2

120 INPUT#1 >A$>BS>ES>B0*B9 * READ IN TITLE AND DESCRIPTION OF

130 PRINT A$ 'JOB* BO =BACKGROUND CORRECTION* B9=HIGHEST

140 PRINT B5 'INTENSITY DUMP.

150 PRINT E$

160 MAT Q=ZER

170 E9=14 •E9=NUMBEH OF COMPLETED RE VOLUT I ONS . ( ALPHA AXIS)

180 X9=E9

190 EP=P6 *E8= NO. OF DUMPS / REVOLUTION

200 M6=360/(2*E9)

210 A1=5/EP

220 A2=A1 /?. 230 F=360/E8

240 Bl =F/2

250 P=3 .1 41 593/1 80

260 B9=B9-B0

270 printbo;b9

280 F0RN=1T0E9 ' READS DATA FROM FILE TO Y MATRIX

290 F0HM=1T0E8

300 INPUT#1*Z

310 IFEND#1 THEN350

320 Y(N*M)=(Z-B0 )/B9*100

330 NEXTM

340 NEXTN • END OF DATA READ.

350 F0RM1=1T0EP

360 F0RN=1T0E9

370 C (N)=Y(N*M1 ) 380 C (2*E9+1 -N)=Y(N*M1

390 NEXTN

400 F0RM=0TCX9 ' START OF CALCULATION OF FOURIER COEFFICIENTS.

410 0=M6/2

C-1
POLEFT Program

420 A(K)=0

430 B(M)=0

440 FCRN=1T0E9*2

450 A(M)=A(M)+C (N)*S IN(P*r<*C)

460 B(M)=B(M)+C(N)*COS(P*M*C)

470 C=C+M6

480 NEXTN . V; . 490 A(K)=A(M)/E9

500 BCM)=B(M)/E9

510 NEXTK • FOURIER END.

520 BO =1000

530 B9=0

540 C=K6/2

550 SB-0

560 FCRN=X9TCE9*X9 ' CALCULATES POINTS BETWEEN OBSERVED POINTS;

570 D(N)=B(0 )/2

5P0 F0RK=1TCX9

590 D(N)=D(N)+A(M)*SIN(C*P*M)+B(M)*CCS(C*P*M)

600 NEXT M ^ 610 C=C+M6/X9

620 IFB9>D(N)THEN650 * FIND POSITION OF CROSS-OVER POINTS.

630 B9=D(N)

640 B3=N

650 IFB0<D(N)THEN680

660 B4=N

670 BO=D(N) ' /

680 NEXTN

690 W4=0

700 C=D(X9)

710 FCRN=X9^'1T0E9*X9

720 CI =D(N)

730 FCRM=INT( (B0+9.999)/10 )*10TCB9STEP10

740 IFC=I^THEN820

750 lFC>r<THEN780

760 IFC! <=MTHEN830 '

. 770 GCTCe20

780 IFCl >=KTHEN800 ;;' v . K

"

' 790 G0TCP20 ^.^ ' ~ ^ :^ POO NEXTK - PIO GCTC830 . 820 GCSUB! 110 '

C-2
POL EFT Program

830 C=C1

840 NEXTN

850 FCRN1=2TCW4 ' ROUTINE FOR ELIMINATING UNWANTED POINTS.

860 IFI (Nl -1 )<>I (Nl )THEN890

870 NEXTNl

880 GOT CI 0 50

890 N5=N1 -1

900 GCSUB 12i0

910 N5 = N1

920 GCSUB1210 ' 930 m-0

9/iO FCRN2=N1 -^ITCW/i

950 IFI (N2-1 )<>I (N2 )THEN980

960 N4=N4+1

970 GCTCIO^jO

980 IF N/j=0 THEN 1010

990 N5=N2-1

1000 GCSUB 1210

1010 N5=N2

1020 GCSUB1210

1030 N4=0

1040 NEXTN2

1050 NEXTI^l

1060 fcrn=1tc9 ' prints cut no. cf points at each level.

1070 printn;q(N);

10 80 NEXTN

1090 PRINT

1100 GOTO 70

1110 W4=W4+1 'ROUTINE TC FIND PCLAR AND CARTESIAN COORDINATES.

1120 A=( (N-1 -X9)*5/X94N1 *A1 )

1 1 30 B=F*M1 -Bl

1140 D=10*TAN(P*A/2

1150 X=D*CCS(P*B)

1160 Y=D*SIN(P*B)

1170 X(W4)=X

1180 Z(W4)=Y

1190 I(W4)=K

1200 RETURN

1210 CUTPUT#2 W (N5 );X(N5 );Z(N5 ); 'OUTPUT TC FILE FOR PLCTTES.

1220 Q ( I (N5 )/10 )=Q< I (N5 )/10 )+l • COUNTS NC CF POINTS AT EACH LEVEL.

1230 RETURN

1240 END

C-3

APPENDIX D

POLEPL Program

10 • PCLEPL PLOTS POINTS ON A POLE FIGUHE FROM DATA STOHED IN A

20 • FILE CREATED BY PCLEFT.

30 DATA4 999 > 2000*4 999* 8000*2000*4 999* 8000*4 999* 9999* 9999

40 PRINT" PLTL"

50 FCRM9=1TC5 ' FORMS CENTER LINE FOR POLE FIGURE.

60 READAl *B1

70 IFK9/2 = INT (M9/2 )THEN100

80 PRINTUSING950*A1 *B1

90 GOTCllO

100 PRINTUSING1000*Al *B1

110 NEXTM9

120 PRINT" PLTT"

130 PRINT"ENTER NAME OF INPUT FILE"J

140 INPUTAS • PERMITS DESIGNATION OF FILE AT HUN TIME CREATED

150 FILESAS • BY POLEFT.

160 REM: INTENSITYPLCTS

170 DIMC (1 1 *3 )*P(1 1 )*CS(10 ) 180 L0=2 .302585093

190 PI =3 .141 592654

200 U7=0

210 W6=H6=4999.5

220 MATREADC ( 1 1 *3 > ' READS DATA FCrt SYMBOLS AVAILABE FOR PLOTTING.

230 DATA-? 70* -90* 1 80 *- 1 PO *0 * 1 PO * -2 70 * -90 * 1 80 *- 1 80 *0 * 1 80

240 DATA -2 70 * 90 * 1 20 * -90 * 2 70 * 1 20 * -2 70 * 90 * 90 * -22 5* 1 35 * 90 * -270 * 90 * 30

250 DATA-240*120*120*-1 P0*1 80*120

260 MATREADP(ll) ' HEAD DATA TO DETERMINE SIZE OF SYMBOLS.

270 DATA2 .5*2.5*2*2*1 .5*1 .5*1 .42*1 .42*2*1 .5*1 .5

280 R3=7.5

290 R6=.075

300 W7=H7=4999 .5/R3

310 PRINT"MAXIMUM R AD I US =" 50 /R3 * "P 0 1 NT SIZE="50/H6

320 Wl =10 t ( INT (LCGCR3 )/L0 )

)

330 R4=INT( .5+R3/W1

)

340 F0RJ=0T0?

350 IFR4< = ( 1 -fj* J)THEN3 70

360 NEXT

J

370 Wl =W1 *(1 +J*J)/10

380 R3=W1 INT ( .5+R3 /Wl

)

390 U9=2

400 H8=0

410 U7=0

420 FCRM9=90TC10STEP-10

430 PRINT"ENTER COLOR AND SYMBOL NO.";

440 INPUT A$*J6 'PERMIT SELECTION OF COLOR A SYMBOL FOR EACH

450 PRINTAS; J6;M9 'INTENSITY AT RUN TIMli.

460 IFJ6=0THEN4 80

470 R5=H6/P(J6)

480 N=U8=0

490 RESTORE*

1

500 1FEND#ITHEN770

510 INPUT#1 * I9*X7* Y7

520 1FI9OM9THEN500 ' SEARCHES FILE FOR DATA WITH CERTAIN

530 N=N+1 • INTENSITY VALUES. IF PASSES TEST IN 510

D-1
POLEPL Program

540 IFJ60OTHEN66O • DATA PREPARED FCR PLOTTING IN SUBPLT ROUT.

550 U9 = l s : V 560 we=X7

570 H8 = Y7 ? I--: 560 G0SUB860

590 IFU8=0THEN500

600 U8=0

610 IFU7=0THEN640

620 U7=0

630 PRINT " PLTT"

640 PRINT "POINT OFF SCALE. X =";X7;" Y =";Y7;" INTENSITY =";I9

650 G0TC500

660 U9=2

670 F0RC9=C ( J6> 1 )TCC ( J6>2 )STEPC < J6*3

)

680 C8=C9*P1 /I 80

690 We=X7+R5*C0S (C8) ; 700 HP=Y7+R5*SIN(C8)

710 IFJ6>2THEN730

720 U9 = l = . 730 GCSUBe60

740 IFU8 = 1 THEN600 . Y .

- - / - : k

750 NEXTC9 -0- - . '' '

- 760 GCT0500 ^ >.: , 'V; . 770 W8'=H8=R3

780 U9=i - -h.-:- 'i

'

790 GCSaB860 / . - 1 . ^ 800 PRINT PLTT"

810 U7=0

820 IFN>0THEN840

830 PRINT " NO POINTS FOUND WITH";I6;" <= INTENSITY <=";I7

840 NEXTM9

850 STOP

860 REM: SUBROUTINE 'SUBPLT* FOR PLOTTING

870 W9=INT(W6+W7*W8)

880 H9 = INT(H6-^H7*H8)

890 IFW9>99990RW9<0CRH9>9999CRH9<0THEN1020

900 IFU7O0THEN930

910 U7 = l 920 PRINT"PLTL"

930 IFU9=0THEN990

940 PRINTUSING950>W9^ H9 ^ . M : 950 :#### ####

t

960 IFU9=1THEN1030

970 U9=0

980 G0TC1030

990 PRINTUSING1000#W9*H9

1000 :#### ####

1010 G0T01030

1020 U8=l

1030 RETURN • x : - A:; ':
APPENDIX E

STRESS Program

5 'PROGRAM FCR CALCULATING STRESS

10 z§ft»* ### »§i*iii ###.###

15 T9=.085959596

20 T8=.91 782/T9

25 PRINT"ENTER NAME OF INPUT FILE";

30 INPUTAS 'PERMITS DESIGNATION OF FILE AT RUN TIME.

35 IFA$="STCP"THEN840

m DIMCS (72 )*D$ (72

)

45 FILESAS

50 INPUT#1 *CS*D$

55 REMC$*DJ

60 P9=&PI/ie0

65 Z9=0

70 M«0

75 INPUT#1 >A1 *S9 'READS STARTING ANGLE A ANGLE OF INCLINATION.

80 X(l )=T9/2

85 FORI «=! TCI 0000 'START OF DATA READING ROUTINE.

90 INPUT* WY

95 IFEND#1THEN13 5

100 IFY<0THEN135 'DETECTS FLAG IN FILE105 S3=S9*P9

110 Z=P9*(A1 }<( I ) ) 115 Yd )=Y/( (1 -TAN(S3 )*C CT( Z/2 ) )* ( 1 CCS C Z ) t2 ) / (2*S I N( Z/2 ) »2 ) ) 120 MsM+l 'ABOVE CALCULATES LP A PSI C CRRECT I CNS - -SEE SAE tl|-182

125 X( I+l ) = X( I )'»-T9

130 NEXT I 135 FOR 1=1 TOM

1/JO Y(2*M+1 -I )aY( I ) 145 NEXTI i 150 M*2*M

155 DIMP(300 )*Q(300 )>A(300 )*B(300 )#C(300 )#D(300 )*X(300 I (600 )*Y<300

)

160 P=2*&PI

165 F0RN=0TCM/4 'ROUTINE FCR CALC . FOURIER CCEF. SEE GANGULEE

170 P(N) = 1

•»• ./17*CCS(P*N*T8/M)

175 Q(N) = ./l7*SIN(P*N*T8/M)

180 M1=A=B»0

185 FCRX=1TCM

190 Xl«X-.5

195 A«A+Y(X)*CCS(P*N*X1 /M)

200 B«B*Y(X)*SIN(P*N*X1 /M)

205 NEXTX

210 A(N)=A/M*2

215 B(N)=B/M*2

E-1
STRESS Program

455 F1=W/W1

460 Wl =W

465 GCTC3 70

470 U(2 )=U(2 )-E2*U(3 )

' v I 475 Z9 = Z9'H , 480 Af =-U(2 )/<2*U(3 ) )- .5 { 485 A3=A2=T9/4+Al 'FINDS TWC-THETA ANGLE.

490 H(Z9)=S9 j 495 Z(Z9)=A3

| 500 PRINTUSING10>A2;S9*A3 / « 505 PRINT" , .

^

510 IFY<-100THEN520

51 5 GCTC70

520 JYCUNG'S MODULUS = #.#!!!! N/^i»2; #.#!!!! KG/MMt2; #.##!!!! PD/IWa

525 JPCISSCN'S RATIO =#.##

530 SSTRESS C CMP CNENT=-# .# ! ! f ! N/MI2; -#.#!!!! KG/MMf2; -#.#!!!! PD/IN!2

535 : ### ###.### #.### -#.### -#.###

540 :PRCBABLE ERROR OF LINEAR FIT =-#.###

545 :RELATI\;E STAND. DEV. OF STRESS =###.# PER CENT

550 tERRCR RELATIVE TC AV. ORDINATE =###.# PER CENT

555 rSTANDARD DEVIATION OF STRESS =-#.#!!!! N/Mt2

560 PRINT"

565 C=D=E=F=S1 =W=0

570 N=.33 'PCISSCN RATIO

575 El =10400000 'YOUNG'S MODULUS FOR 7075 AL. ALLOY.

580 El =6894 .75*E1

585 PRINTCS

590 PRINT • ^ V 595 PRINT

600 FCRI=1TCZ9 'START OF STRESS ROUTINE.

605 S3=P9*H( I ) 610 Y( I )=Z(I )-Z(l ) 615 X( I )=SIN(S3 )*SIN(S3

)

620 C=C+Y(I )

ft

•f

E-2

I
II

STRESS Program

220 NEXTN

225 A(0)=A(0)/2

230 FCRN=OTCM/A 'ROUTINE FOR FINDING ALPHAl FOURIER COEF.

; 235 E=P(N)*P(N)+Q(N)*Q(N)

I 2410 C(N) = (A(N)*P(N)+Q(N)*B(N) )/E

2A5 D(N)=(-A(N)*Q(N)+B(N)*P(N) )/E

' 250 NEXTN

255 A3=0

260 FCRX=2T0M*2

265 Xl=X-.5

270 1=0

275 FCRN=0TCM/4 'CALCULATES ALPHAl PEAK.

280 I=I+C (N)*CCS (P*N*X1 /(M*4i ) )+D ( N) *S I N(P*N*Xl / (M*4 ) ) 285 NEXTN

I 290 I(X)=I

' 295 IFA3>ITHEN310 'FIND HIGHEST POINT IN ALPHAl PEAK.

300 A3=I

305 A2=X

310 NEXTX

315 T7=T9/4*(A2-.5)+Al

320 PRINTUSINGIO jA2*S9*T7*T7+T8*T9

325 M = 60

330 FCRI=1TCK 'START OF PARABOLA FITTING ROUTINE

335 Yd ) = I (A2-31 +1 ) 340 X(I)=A2-31*I

345 P(I)=0

350 Q(I)=1

355 NEXT I 360 I«:E2sFl=0

365 W1=M

370 W«=E1=0

375 1=1+1

380 F0RL = lTCr^

385 W=W+Y(L)*Q (L)

390 El =E1 -^XCD^Q (L)*Q (L)

395 NEXTL

400 U(I)=V/W1

405 IFI-3>=0THEN4 70

410 E1=E1/W1

415 E2=E2*E1

420 W=0

425 FCHL=1TCM

430 U=(X(L)-E1 )*Q(L)-F1 *P(L)

435 P(L)=Q(L)

440 Q(L)=V

445 W=W+V*V

450 NEXTL

E-3
STRESS Program

665 D=D-«-X(f)t2

630 E=E-^X< I )*Y( I ) 635 F=F + X(I ) 640 NEXTI

645 D5=D*Z9-F*F

650 Ql «(Z9*E-C*F)/D5

655 Q2=(C*D-E*F)/D5

660 PRINTUSING520/EI ^El /9806650/El /6P94.75

665 PRINT

670 PRINTUSING525>N

675 PRINT

680 S = -P9*Q1 *E1 /<2*(H-N)*TAN( .5*P9*Z(1 ) ) ) 685 PRINTUSING530*S*S/9P06650*S/6894» .75

690 PRINT

695 IFS<0THEN710

700 PRINT"THIS IS A TENSILE STRESS IN THE PLANE CF THE SURFACE."

705 GCT0715

710 PRINT"THIS IS A COMPRESSIVE STRESS IN THE PLANE CF THE SURFACE

715 PRINT

720 PRINT

725 PRINT"DELTA 2+THETA FITTED TC LSE STRAIGHT LINE:"

730 PRINT" DEL 2TH = (" ;Q I ;" )* (S I N PSI)t2 (";Q2;")"

735 PRINT

740 PRINT" ANGLE OF" .-.„ 745 PRINT"INCLINATICN 2 THETA SINt2 DEL 2TH LSE FIT

750 FCRI=ITCZ9

755 Z=Q1*XCI)•^Q2 ^,T^ 7

760 PRINTUSING535>H(n>Z(n*X(n*Y(I

765 S1=S1*(Y(I)-Z)t2

770 NEXT I 775 PRINT

7P0 S2=.6754*SQR<S1 /(Z9-2))

785 PRINTUSING540*S2

790 C=C/Z9 / 795 PRINTUSING550*ABS(100*S2/C

)

800 PRINT

805 PRINT

810 S3=SQR(S1 *M/(D5*<^5-2)))

815 S4eABS(S3*S/Ql ) 820 PRINTUS ING555*S4

825 PRINTUSING545*ABS(100*S4/S)

830 PRINT"

835 GCTC25

840 END

E-4
RESIDUAL STRESS ANALYSIS

AL BLOCK #1* BOTTOM SIDE

SURFACE S3/2

YOUNG'S MODULUS = 7.2E>10 N/Mt2i 7.3E*03 KG/MM»2; 1 .O^JE-^O? PD/IN«2

POISSON*S RATIO » .33

STRESS COMPONENT"-! .2E+08 N/MI2; -l.2E*01 KG/MMf2; -l •lE-^OA PD/lNf2

THIS IS A COMPRESSIVE STRESS IN THE PLANE OF THE SURFACE.

DELTA 2*THETA FITTED TO LSE STRAIGHT LINEt

DEL 2TH »= ( 1 .16305 )*(SIN PSI)«2 < .122302 ) ANGLE OF

INCLINATION 2 THETA

155.305

155.522

1 55.781

156.204

156.147

SINt2

.000

.067

.250

.500

.750

DEL 2TH LSE FIT

0

15

30

A5

60

.000

.217

.476

.899

.842

• 122

.200

.413

.704

.995

PROBABLE ERROR

ERROR RELATIVE

OF LINEAR FIT

TO AV. ORDINATE »

• 11

1

22.7 PER CENT

STANDARD DEVIATION OF STRESS « 2.7E'»'07 N/Mt2

RELATIVE STAND. DEV^ OF STRESS 22.6 PER CENT

E-5
RESIDUAL STRESS ANALYSIS

AL BLOCK #1# TCP SIDE CENTER

SURFACE SI

YOUNG'S MODULUS « 7.2E+10 N/Mt21 7.3E403 KG/MMt2l 1 .04E+07 PD/lNt2

POISSCN'S RATIO » OS

STRESS COMPONENT"-! .lEi-0 8 N/MI2J -1 .2E-»'01 KG/MMI2j -I .6E-»-04i PD/INI2

THIS IS A COMPRESSIVE STRESS IN THE PLANE OF THE SURFACE.

DELTA 2*THETA FITTED TO LSE STRAIGHT LINEi

DEL 2TH - ( 1.09988 >«(S1N PSI)»2 ( 5.90986E-2 ) ANGLE OF

INCLINATION 2 THETA

155.228

155.410

155.585

155.834

156.102

SINt2

.000

.067

.250

.500

.750

DEL 2TH LSE FIT

0

15

30

45

60

.000

.1 82

.357

.606

.874

.059

.133

.334

.609

• 884

PROBABLE ERROR OF LINEAR FIT

ERROR RELATIVE TO AV. ORDINATE

.032

7.8 PER CENT

STANDARD DEVIATION OF STRESS - 7.7E*06 N/Mt2

RELATIVE STAND. DEV. OF STRESS 6.8 PER CENT

E-6
RESIDUAL STRESS ANALYSIS

AL BLOCK* TCP> POLISHED NOT ETCHED

SURFACE SI

YOUNG'S MODULUS » 7.2E + 10 N/Mt2J 7.3E*03 KG/MMt2; 1 .O/JE+07 PD/INt2

PCISSON'S RATIO = .33

STRESS COMPONENTa-1 .4E*08 N/MI2; -I ./lE^Ol KG/MMI2; -2 .0E404» PD/INI2

THIS IS A COMPRESSIVE STRESS IN THE PLANE OF THE SURFACE*

DELTA 2*THETA FITTED TO LSE STRAIGHT LINEt

DEL 2TH » ( 1.32547 )*<SIN PSI)»2 ( .033 ) ANGLE OF

INCLINATION 2 THETA

1 55.1 83

I 55.380

155.584

155.699

156.311

SINt2

.000

.067

.250

.500

.750

DEL 2TH LSE FIT

0

15

30

45

60

.000

.197

.401

.516

1 .128

.033

.122

.364

.696

1 .027

PROBABLE ERROR OF LINEAR FIT « .088

ERROR RELATIVE TO AV. ORDINATE « 19.6 PER CENT

STANDARD DEVIATION OF STRESS - 2.2E*07 N/Mt2

RELATIVE STAND. DEV. OF STRESS » 15.7 PER CENT

E-7
RESIDUAL STRESS ANALYSIS

AL BLOCK* BOTTOM WITH HOLE AS REC '

D

SURFACE S2

YOUNG'S MODULUS » T.aE-t-lO N/M»2; 7.3E*03 KG/MM»2; 1 .04E-»"07 PD/INt2

POISSON'S RATIO « .33

STRESS COMPONENTe-1 .lE^Oe N/M!2; -l.lE-^Ol KG/MMf2; -1 .eE-fQ^i PD/INf2

THIS IS A COMPRESSIVE STRESS IN THE PLANE OF THE SURFACE.

DELTA 2*THETA FITTED TO LSE STRAIGHT LINEl

DEL 2TH e < 1.06992 )*(SIN PSI>«2 ( 7.88835E-3 ) ANGLE OF

INCLINATION 2 THETA

1 55.336

1 55.427

1 55.583

155.928

1 56*122

SIN»2

.000

.067

.250

.500

.750

DEL 2TH LSE FIT

0

15

30

45

60

.000

.091

.247

.592

.786

.008

.080

.275

.543

.810

PROBABLE ERROR OF LINEAR FIT » .025

ERROR RELATIVE TO AV. ORDINATE » 7.2 PER CENT

STANDARD DEVIATION OF STRESS " 6.0E-f06 N/M»2

RELATIVE STAND. DEV. OF STRESS « 5.5 PER CENT
RESIDUAL STRESS ANALYSIS

AL BLCXK SLICE* SIDE OPPOSITE HOLE* CENTER

SURFACE S4/1

YOUNG'S MODULUS = 7.2E+10 N/Mt2; 7.3E+03 KG/MMt2; 1.04E+07 PD/INt2

POISSON'S RATIO = .33

STRESS C0MP0NENT = -1 •OE+08 N/Mf2; -l.OE-fQl KG/MM!2J -|.5E-fO/| PD/INf2

THIS IS A COMPRESSIVE STRESS IN THE PLANE OF THE SURFACE.

DELTA 2*THETA FITTED TO LSE STRAIGHT LINEt

DEL 2TH »= ( .986165 )*(SIN PSI)t2 ( 4.67392E-2 ) ANGLE OF

INCLINATION 2 THETA

155.387

1 55 .567

1 55 .614

1 56.016

1 56.1 30

SIN»2

.000

.067

.250

• 500

.750

DEL 2TH LSE FIT

0

15

30

45

60

.000

.1 80

.227

.629

.743

.047

.113

.293

.540

.786

PROBABLE ERROR

ERROR RELATIVE

OF LINEAR FIT

TO AV. ORDINATE = .056

15.9 PER CENT

STANDARD DEVIATION OF STRESS « 1 .4E*07 N/M»2

RELATIVE STAND. DEV. OF STRESS « 13.6 PER CENT

J

E-9
RESIDUAL STRESS ANALYSIS

AL BLCCK> EDGE* OPPOSITE FROM HOLE

SURFACE SI

YOUNG'S MODULUS = 7.2E+10 N/Mt2; 7.3E^03 KG/MM»2; 1 .04E^07 PD/INt2 '

POlSSCN'S RATIO = .33

STRESS C0MP0NENT = -1 .OE+08 N/MI2; -l.OE+Ol KG/MMf2; -1 .5E-^0<I PD/INI2

THIS IS A COMPRESSIVE STRESS IN THE PLANE OF THE SURFACE.

DELTA 2*THETA FITTED TO LSE STRAIGHT LINE?

DEL 2TH = < .994081 )*(SIN PSI)»2 (-1.29431E-2 ) ANGLE OF

INCLINATION 2 THETA

1 55.263

155.319

155.491

155.717

156.01

8

SINt2

.000

.067

.250

.500

.750

DEL 2TH LSE FIT

0

15

30

45

60

.000

.056

.228

.454

.755

.013

.054

.236

.484

.733

PROBABLE ERROR OF LINEAR FIT

ERROR RELATIVE TO AV. ORDINATE « .016

5.3 PER CENT

STANDARD DEVIATION OF STRESS » 3.9E'»-06 N/Mt2

RELATIVE STAND. DEV. OF STRESS « 3.8 PER CENT

E-10
RESIDUAL STRESS ANALYSIS

AL BLCCK> SLICE* SIDE OPPOSITE HOLE

SURFACE S5/2

YOUNG'S MODULUS = 7.2E+10 N/M»2; 7.3E^03 KG/MMt2j 1 .0/iE-»-0 7 PD/IN»2

POISSON'S RATIO « .33

STRESS C0MP0NENT»-2 .6E*0 7 N/M!2; -2.6E*00 KG/MM!2; -3.8E*03 PD/1N!2

THIS IS A COMPRESSIVE STRESS IN THE PLANE OF THE SURFACE.

DELTA 2*THETA FITTED TO LSE STRAIGHT LINEt

DEL 2TH • ( .254154 )*<SINPSI)»2 ( 5.13481E-2 ) ANGLE OF

INCLINATION 2 THETA SINt2 DEL 2TH LSE FIT

0 155.506 .000 .000 .051

15 155.573 .067 .067 .068

30 155.703 .250 .197 .115

45 155.678 .500 .172 .178

60 155.725 .750 .219 .242

PROBABLE ERROR OF LINEAR FIT - .039

ERROR RELATIVE TO AV* ORDINATE "29-7 PER CENT

STANDARD DEVIATION OF STRESS 9.4E*06 N/Mt2

RELATIVE STAND. DEV. OF STRESS 36.4 PER CENT

500 DATA EXHAUSTED

NOW AT 500

READY

USCOMM-NBS-DC E-11
NBS-114A (REV 7-73) U^. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. IM'hl 1< A 1 ION OR RKI-'OKT NO.

NBSIR 75-685

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

Improved Ultrasonic Standard Reference Blocks

5. Publication Date April 1975

6. Performing Organization Code

7. AUTHOR(S) D. G. Eitzen, G. F. Sushinsky, D. J. Chwirut and

C. J. Bechtoldt and A. W. Ruff

8. Performing Organ. Report No. NBSIR 75-685

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 2130443

11. f'ontract/Grant No. DO F33615-74-M6752

12. Sponsoring Organization Name and (Complete Address (Street, City, Slate, ZIP)

Air Force Materials Laboratory

National Aeronautics and Space Administration

and Army Materials and Mechanics Research Center

13. Type of Report & Period ^"^"^•^ Interim Report

1-1-74 to 12-31-74

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

14. ABSTRACT (A 200-word or leas factual auatmmry oi atomt mitfiHicmtt inlomation. II document includes a si^iticant

bibliography or literature survey, mention it here.)

A program to improve the quality, reproducibility and reliability of nondestructive

testing through the development of improved ASTM-type ultrasonic reference standards

is described. Reference blocks of aluminum, steel, and titanium alloys are to be considered. Equipment representing the state-of-the-art in laboratory and field ultrasonic

equipment was obtained and evaluated. RF and spectral data on ten sets of ultrasonic

reference blocks have been taken as part of a task to quantify the variability in re- sponse from nominally identical blocks. Techniques for residual stress, preferred

orientation, and micro-structural measurements were refined and are applied to a referente

block rejected by the manufacturer during fabrication in order to evaluate the effect

of metallurgical condition on block response. New fabrication techniques for reference

blocks are dis cussed and ASTM activities are summarized.

17. KEY WORDS (six to twelve entries; alphabetical o*der; capitalize only (he firmt lettmr ot the lirat key word tmtema a proper name; separated by semicolons) Aluminum ultrasonlc Standards; ASTM-type reference blocks;

fabrication of reference blocks; immersion testing; longitudinal waves; metallurgical

variables; nondestructive testing, pulse-echo; steel ultrasonic standards; titanium

ultrasonic standards; ultrasonics.

18. AVAILABILITY Qc] Unlimited

I

I For Official Distribution. Do Not Release to NTIS

Order From Sup. of Doc, U.S. Cjovernment Printing Office Washington, D.C. 20402, SD Cat. No. C: 13 |X I Order From National Technical Information Service (NTIS)

Springfield, Virginia 221'il

19. SECURITY CLASS

(THIS REPORT)

UNC:L ASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO, OF PAGES

82

22. Price

$4.75

USCOMM-DC 29042-P74