Reference 111! II ill I III

*1110*4 MRdfiO?

NBSIR 78-1582

Report No. 9

A Metallurgical Analysis of an

ASTM A212-B Steel Tank Car

Head Plate

J G Early

Fracture and Deformation Division

National Measurement Laboratory

National Bureau of Standards

Washington 0 C 20234

September 1978

Issued January 1 979

Fmal Report

Prepared for —QC100

. 1)56

Federal Railroad Administration

Z ?rtment of Transportation

ungton. D C. 20591

73-1532

1979

. aTIONAJL alWIMi

or stantjabHI

i.ibrakt

NBSIR 78 1582

JUL 2 1 1980

not acc '&f

REPORT NO. 9

A METALLURGICAL ANALYSIS OF AN

J G Early

Fracture and Deformation Division

National Measurement Laboratory

National Bureau of Standards

Washington. D C 20234

September 1978

Issued January 1979

Final Report

This document has been prepared for the use of the

- • -el R=i road Administration, Department of Transportation.

Responsibility for its further use rests with that

agency NBS requests that if release to the general

pubnc is contemplated, such action be taken only

after consultation with the Office of Public Affairs

at the National Bureau of Standards.”

Prepared for Federal Railroad Administration

Department of Transportation

Washington, D C. 20591

U S DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr Sidney Harman, Under Secretary

Jordan J Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS. Ernest Ambler, Director

ASTM A21 2-B STEEL TANK CAR

HEAD PLATE

ABSTRACT

-\ - •

=. lurgicnl evaluation of a steel plate sample was requested by

Railroad Administration, Department of Transportation. An

••••'a* : .:a- : was carried out at NBS to determine if the head plate sample

:onformed with the appropriate specification for tank car materials. The

i behavior of the plate sample was also determined.

Tr. Mas taken from the A-head plate of tank car SOEX 3033

involved ident near Winder, Georgia. The A-head plate was ll produced to specification ASTM A212-65, Grade B steel.

of laboratory check chemical analyses indicated that the

sar * he chemical requirements of ASTM A212-65, Grade B steel,

results of ambient- temperature bend tests and tensile tests showed

sample satisfied both the bend requirements and the tensile

; : r-r.ent? but failed to meet the minimum ultimate tensile

ngtn and yield point requirements of ASTM A212-65, Grade B steel.

suits of metallographic analyses revealed substantial variation

-. ^restructure in the plate thickness direction. The observed

pri'T austenite grain size and large ferrite grain size is

:onsiste th the coarse-grain steelmaking practice allowed for ASTM

A212 steel and a high finishing temperature during fabrication. Hardness

easurene- e microstructure correlated well with the measured

tensile strength properties.

The nil-ductility transition temperature was determined to be 30 F,

.e equal to the highest value reported for a group of tank car plate

sample ling both accident samples and current and previously

allowed tank car plate materials.

The results of Charpy V-notch tests established that the 15 ft- lb

cion and 50% shear fracture appearance transition

re measured for both longitudinal and transverse specimens

r ill Hoove 60 ? and within normal tank car service temperature range.

The high transition temperatures are related to both the coarse prior

i_st-:mte grain size and large ferrite grain size observed in the microstructure and the steel chemistry.

Table of Contents

Page

ABSTRACT

INTRODUCTION 1

. PURPOSE 2

: . EXPERIMENTAL PROCEDURES 2

3.1 Macroscopic Observations and Rolling

D: rection Determination 2

Ihemical Analysis 2

Tensile Testing 2

.4 ?-vid Testing 3

Impact Testing 3

3.6 Metallographic Studies and Hardness Testing 4

4. RESULTS AND DISCUSSION 4

-nical Composition 4

4.: Macroscopic Observations 5

4. Metallographic Analysis 5

; . 4 Hardness Measurements 6

4 . : Tensile Properties 6

4.6 Bend Behavior 8

4.7 Inclusion Content 8

4.8 Impact Properties 9

4.8.1 Nil-Ductility Transition Temperature 9

4.8.2 Charpy V-notch Tests 9

4.9 General Discussion 11

i
Table of Contents (continued)

Page

5. CONCLUSIONS 13

6. ACKNOWLEDGEMENT 14

REFERENCES 15

TABLES

I. Chemical Composition of the Winder Sample

II. Tensile Properties of the Winder Sample

III. Bend Behavior of Winder Sample

IV. QTM Inclusion Content Rating of Winder Sample

V. Drop-Weight Test Behavior of Winder Plate

VI. Charpy V-notch Impact Transition Temperatures for Four Head Plate

Steels Tested at NBS

VII. Comparison of Charpy V-notch Upper-Shelf Behavior of Four Head

Plates Tested at NBS

VIII. Comparison of Selected Results From Check Chemical Analyses of

Four Head Plates Tested at NBS

FIGURES

1. Photograph of Tank Car SOEX 3033 at Accident Site Near Winder, GA.

2. Close-up of A-Head, Tank Car SOEX 3033

3. Winder Plate Sample

4. Winder Plate Sample Showing Location and Orientation of Test

Specimens

5. Schematic Shwoing Planes Associated With the Rolling Direction in

a Plate

6. Representative Photomicrographs of Inclusions on Two Orthogonal

Planes

n
FIGURES (continued)

heritage of Microstructure Through Cross-Section of the Plate

Photomicrographs of Typical Microstructure from Zones 2 and 3

Representative Photomicrographs of a Section Through a Transverse

Tensile Specimen

1"). Bend Test Specimens

11. Drop-Weight Test Specimens

Zharpy V-notch Impact Test Results for Head Plate Specimens Taken

From ASTM A212 Steel Plate

Fracture Appearance of Selected Charpy Specimens

APPENDIX A - Charpy Impact Test Results

~able Al. Energy Absorption for LT Orientation

Table A2. Lateral Expansion for LT Orientation

' 3 . Shear Fracture Appearance for LT Orientation

'.ib- A4. Energy Absorption for TL Orientation

Table A5. Lateral Expansion for TL Orientation

Table A6 . Shear Fracture Appearance for TL Orientation

iii

1. INTRODUCTION

g - 'tail iigical evaluation of a steel plate sample (Winder sample)

•as requested by the Federal Railroad Administration, Department of

Transportation. The Winder plate sample was reported [1] to have

beer, taker from a tank car identified as SOEX 3033 involved in an

\ cident or the Seaboard Coast Line Railroad at approximately 5:25 a.m. on April 6, 1975 near Winder, Georgia. The tank car carrying liquified

re * r

' leum gas ,LFG' , was punctured in the tank head and propelled by

x, m of the liquified gas a distance of about 450 feet from the

i-'r

site. As the tank car rocketed away from the accident site,

1 1 y struck the asphalt pavement of a nearby highway creating

which ignited the LPG vapor. The fracture surfaces near the

-

. . : . art site on this plate were reportedly perpendicular to the

surfaces with no evidence of plate thinning at the fracture edge and

mode of failure propagation was stated to be brittle. The ambient

temperature at the accident site was estimated to have been about 40 F.

The A-head of the tank car, photographed at the accident site [2] v i tr.own in Figure 1, contained the Winder sample submitted to the

Rational Bureau of Standards (NBS ) for metallurgical evaluation. The

>- ir.ple was reported to have been cut from an undeformed region

A-head, as shown in Figure 2. The head plate material used in the

fabricat )f the A-head was reported [1] to have been produced to the

specification for ASTM A-212, Grade B, F.Q. steel.

It should be noted that the test specimens taken from the Winder plate

sample for t'r -estigation were in the as-rolled, cold-worked, and

•- ‘i condition. The cold work resulted primarily from the

original fabr n of the tank-car head and possibly from some slight,

. at indeterminate amount of reforming during the puncture of the tank car.

H vever, the shape and appearance of the Winder plate sample indicated

ble reforming occurred in this sample. It is therefore

. that the observations and properties reported in this metallurgical

i. .a- r f the head plate are relevant to the A-head plate of the tank

car in service.

2. PURPOSE

The principal purpose of this metallurgical evaluation was to determine

if t e Winder head-plate sample, taken from tank car SOEX 3033, conformed

witn t.te specification ASTM A212-65 for high-tensile strength, carbonsilicon steel plates for pressure vessels, and to determine the impact test

behavior of this plate sample.

T.te isolated numbers in brackets refer to references listed at the

end of this report.

1
3. EXPERIMENTAL PROCEDURES

The orientation of the Winder plate sample with respect to the

principal rolling direction of the plate was determined, prior to the

preparation of test specimens, by an examination of inclusion morphology.

Chemical analyses, tensile properties and bend characteristics were determined and compared with the requirements of ASTM A212-65. In

addition to the required tests, standard Charpy V-notch impact tests,

drop-weight nil-ductility transition temperature tests, inclusion

content ratings and a hardness survey were performed and macroscopic and

microscopic observations were made.

The results of pre-cracked Charpy V-notch impact tests and dynamictear tests will be reported in a subsequent report.

3. 1 Macroscopic Observations and Rolling Direction Determination

The Winder plate sample was macroscopically examined for evidence of

both deformation resulting from the accident and heating effects resulting

from the burning LPG. The principal rolling direction was determined using

a quantitative television microscope (QTM) by measuring inclusion lengths

on a series of specimens oriented at fixed angles with respect to an arbitrary reference line scribed on the plate surface (Figure 3) . The

location and orientation of test specimens taken from the Winder plate are shown in Figure 4. The longitudinal axes of the longitudinal and transverse

specimens are aligned respectively, parallel and perpendicular to the

principal plate rolling direction.

3 . 2 Chemical Analysis

Check chemical analyses (by combustion-conductometric and emission

spectroscopy) were conducted by a commercial testing laboratory at the

quarter- thickness position of the chemistry sample (Figure 3) to determine

if the composition satisfied the requirements of ASTM A212-65, Grade B

steel.

3 . 3 Tensile Testing

Two longitudinal and two transverse specimens, 0.250 inches in diameter

with a 1-inch-gage length, were taken as closely as possible from the

quarter-thickness position of the plate and tested in accordance with ASTM

A370-73,(b) Mechanical Testing of Steel Products.

The General Conditions for Delivery section of the specification for

ASTM A212-65 tank-car steel requires that materials furnished to these

specifications conform to the applicable requirements of ASTM Specification A20-65. Specification A20-65 requires for plates 1-1/2 inch and

under in thickness, tension test specimens shall be Standard Rectangular

Tension Test Specimens with 8-inch-gage length and for plates over 1-1/2

inches in thickness, tension test specimens shall be Standard Round

Tension Test Specimens with 2-inch-gage length, 0.505 inches in diameter.

However, ASTM A20-65 requires the tests be conducted in accordance with

the ASTM Methods and Definitions A370, for the Mechanical Testing of Steel

2
3. 4 Bend Testing

Two bend-test specimens, one longitudinal and one transverse, were prepared with dimensions 3/8 inch thick x 1-1/2 inch wide' c ^ x 6 inches

: and with the outside surface of the tank car being the outer curve

of the bend. In accordance with ASTM A212-65 and ASTM A370-73, the

.'LT.ens were bent through an inside diameter of 3/4 inches, so as to

provide the required bend ratio of bend diameter (d) to thickness (t)

equal to 2.

3 . 5 Impact Testing

The r - of two types of impact tests are given in this report:

drop-weight nil-ductility transition temperature (NDTT) tests, carried

3Ut in accordance with A M 5208-69, and standard Charpy V-notch (CVN)

rimed out in accordance with ASTM E23-72. Specimens for the NDTT

tests were full-plate-thickness type specimens with length and width

ims of 5 inches and 2 inches, respectively, and a saw-cut notch

located on a weld bead on the outside plate surface. The Charpy specimens

were standard size and were machined from the quarter thickness location

of the plate.

ir p-weight test was originally developed to study the initiation

• fractures in low and intermediate structural steels. The test

*

. ASTM A370-73 allows Standard Round Tension Test Specimens

and Snail Size Specimens proportional to the Standard Round Specimen

• o be used when it is necessary to test material from which the

tar lari Rectangular Test Specimens of 8-inch- and 2-inch-gage length

be prepared. Because the amount of plate material available for

- . hiring test samples was limited, it would not have been feasible to

rep ; r the Standard Rectangular Tension Specimens. The Standard Round

Ter.s:;: Test Specimen, 0.505 inches in diameter, has a 2-inch-gage

length, thus allowing direct comparison between test result and

specification; however, the threaded end section requires a diameter of

4 inches and due to the head-plate curvature the plate thickness was insufficient. Thus, for test consistency, the tensile test specimens

-re -achined to standard 0.250-inch-diameter round test specimens with

a 1-inch-gage length.

The width of the bend specimens significantly affects the bend ductility,

lieter ^ has reported that ductility, in terms of the bend angle before

cracking occurs in a material in bending, decreases with increasing

values of the width to thickness ratio, w/t, until a terminal level is

achieved at a w/t equal to about 8. As this ratio of w/t increases, the

ratio of the transverse stress to the circumferential stress also

increases and the bend ductility of the specimen decreases. Therefore,

m order to have a bend test specimen of "intermediate" severity, the

w/t ratio of 4 was chosen for the bend specimens tested at NBS.

3
is used to measure the nil-ductility transition (NDT) temperature (the

temperature above which many steels undergo a transition from brittle to

ductile fracture behavior) and permits the evaluation of the ability of a steel to resist crack propagation under yield point loading in the presence

of a small flaw. The NDT temperature is independent of the specimen

orientation with respect to the plate rolling direction.

The LT and TL specimens used in this study are the standard longitudinal

and transverse orientations used in previous reports [4-7]. For all sets of

impact specimens, tests were conducted over a temperature range selected to

show the transition from ductile to brittle fracture.

3 . 6 Metallographic Studies and Hardness Testing

Representative photomicrographs, oriented as shown in Figure 5, were obtained on metallographic samples located as shown in Figure 3. Metallographic observations were made on selected polished and etched areas of

longitudinal C planes and transverse B planes. The ferrite grain size was measured in accordance with ASTM E112-74, Intercept Method.

Rockwell B hardness measurements were taken on a specimen adjacent to

the metallographic specimens and correlated with the microstructure.

The inclusion content was determined on longitudinal C planes by a QTM

method which rates the inclusion content as an area percent of the section

being rated. The area percentage measurements were made at two quarter

thickness locations and at the mid thickness. In addition, the worst field

and the number of fields with inclusion area greater than 0.5 percent, were tabulated. In general, the QTM methods described in the literature

[5,8] were used.

4. RESULTS AND DISCUSSION

4. 1 Chemical Composition

The chemical composition, as determined by the check analysis of the

plate sample, is given in Table I, along with the chemical requirements of

ASTM A212-65, Grade B steel. The results of the check analysis indicates

that the composition of the Winder sample satisfies the chemical requirements for ASTM A212-65, Grade B steel. It should be noted, however, that

the carbon and manganese levels are 22 percent and 19 percent, respectively,

below the maximum level allowed for this grade of steel.

Specification A212-65 allows either coarse-or fine-grain steelmaking

practice for plates of less than two inches in thickness and the lack of

detectable amounts of vanadium and aluminum reported in the check analysis

indicated that a coarse-grain steelmaking practice was followed. The same deoxidation practice was apparently followed for the previous ASTM A212-B

head plate tested at NBS [4]

.

4
Macroscopic Observations

The appearance of the Winder plate sample was compared with a series of t'graphs taken of the tank car at the accident site. Almost all of the

external plate surface of the sample was covered with paint except near the

tcrch-cut -'dges and in regions containing several scratches and gouges.

7 ' appearance of this surface coating was taken as evidence that the region

- th tank-car head from which the NBS sample was removed did not experience

any significant heating as a result of the fire following the accident. A

c rear i son between Figure 1 and Figures 2 and 3 shows that several of the

: :ces occurred after the accident and probably resulted during the removal

t: the tank car from its resting site. Further, the specimen layout

?' i cure 4 was chosen to avoid most of the gouged areas. Therefore, the

results of this study are believed to represent the as-fabricated head plate.

4 . 3 Metallographic Analysis

Representative photomicrographs taken at low magnification on longitudinal

1 mes and transverse B planes are shown in the unetched condition in

Figure 6. The large difference in inclusion length between the longitudinal

ar.d transverse planes indicates that this head plate was not extensively

cross-rolled prior to the forming operation.

Representative microstructures are shown in the etched condition in

Figures ” and 3. The microstructure consists of large pearlite colonies

and ferrite grains with little evidence of banding and is similar to that

reported for another head-plate sample of ASTM A212-B steel [4]. In the

• re c : .ate, however, there is a high degree of variability from plate

surface to plate surface. A montage of the longitudinal plane (Figure 7) i restructure from plate surface to plate surface reveals three distinct

zones.

first zone (Zone 1) consists of a narrow decarburized layer, about

us thick, located at both the inside and outside plate surface.

The : reser.ee of the decarburized layer at both plate surfaces indicates

that decarburization probably occurred during the plate rolling and

: r~

:

- : cperations and/or the stress-relieving operation after fabrication

of the tank car.

Proceeding inward from both plate surfaces, the second zone (Zone 2)

,

about 7.13 inches thick, contains large pearlite colonies within which are found acicular or Widmanstatten side plates of ferrite. The pearlite

colonies are observed to be generally surrounded by proeutectoid ferrite

loiated on the prior austenite grain boundaries, as shown in Figure 8a.

The third zone (Zone 3), a large region about 0.37 inches thick centered

about the plate mid- thickness location, contains a large amount of proeutectoid ferrite which generally masks the prior austenite grain boundaries,

as shown in Figure 8b.

5
The determination of the prior austenite grain size was made possible

because of the outline of ferrite located at the prior austenite grain

boundaries. The prior austenite grain size was estimated to be ASTM No.

1-2 through comparison with Plate I grain size charts from ASTM E 112.

The ferrite grain size of the non-Widmanstatten ferrite grains was ASTM No.

7.1 as determined by the circular intercept method from ASTM E 112. The

coarse prior austenite grain sizes found in both the Winder plate sample

and the other ASTM A212-B head-plate sample previously studied at NBS are consistent with t^ie conclusions that both steels were produced to coarse- grain practice. ^ A coarse austenite grain size will promote the

formation of Widmanstatten ferrite in steel containing less that 0.3-0.

4

percent- by-weight carbon [9], as seen in Figures 7 and 8.

The symmetry of the microstructural zones (Figure 7) about the plate

midthickness location is related to thermal and mechanical effects during

processing of the plate because the prior austenite grain size and the

cooling rate can affect the relative amounts, grain sizes, and distributions

of ferrite and pearlite in these low-carbon steels. [10] Large pearlite colonies

and a coarse ferrite grain size are two of the factors which promote high

impact transition temperatures.

4.4 Hardness Measurements

The results of hardness measurements are given in Figure 7. The Rockwell

B hardness is highly variable, ranging from 73 to 79, and can be correlated

with the microstructure. The region of highest hardness, HRB 77 to 79,

corresponds to Zone 2 which exhibits the highest proportion of the relatively

hard pearlite phase. The region of lowest hardness, excluding the

decarburized layer, corresponds to Zone 3, which consists of extensive

areas of the relatively soft ferrite phase.

4 . 5 Tensile Properties

The tensile properties of the Winder sample are given in Table II alona

with the requirements of ASTM A212-B-65. The results of the longitudinal

and transverse specimens indicate that the steel meets the minimum elongation

requirement of 21 percent but does not meet the minimum ultimate tensile

strength or yield-point requirements of 70 ksi and 38 ksi, respectively.

The average values of longitudinal and transverse ultimate tensile

strength were 67.9 ksi and 67.6 ksi, respectively, while the average

0.2 percent offset yield-strength values were 33.0 ksi and 32.2 ksi.

Although the final austenite grain size of hot-worked products is strongly

influenced by the finishing temperature of the working operation, steels

produced to fine-grain practice resist grain coarsening over a large range

of finishing temperatures. Ferrite grain size and pearlite colony size are strongly influenced by the prior austenite grain size and by the

cooling rate through the transformation temperature, and are therefore

affected by deoxidation practice and finishing temperatures.

6
respectively. These values indicate that there was little anisotropy in the

strength ot the plate in the plane of the rolling direction; a finding

wit. earlier results on both head and shell plates of ASTM A212

and AAR M128 steel . [ 12 , 13

]

'.er evidence that the mechanical behavior of this plate sample was

- i:te 'ted by the accident can be found in the measured strength

properties. The possible exposure to fire and plastic deformation could

lead te strain aging of the plate which can manifest itself by the presence

f ;;ur; yield point, increases in ultimate tensile strength and yield

strength, and an ase in the ductile-to-brittle transition temperature,

‘ - isured by Charpy V-notch impact tests. The strength properties,

such as ultimate tensile strength and yield strength, of ferritic steels

such as ASTM A212-B are determined primarily by the chemical composition,

especially the amounts of carbon and manganese. The measured ultimatetensile-strength and yield-strength values of the Winder sample are below

:ification minimum requirements. This is consistent with the lower

;arbon and manganese levels found by the check chemical analysis. Further,

• a sharp yield point in three of the four tensile test

ciaens (see Table II) indicates that any plastic deformation received

by the plate sample as a result of the accident was insufficient to eliminate the

sharp yield point. Thus the measured strength properties indicate that

--1 d r no strain aging occurred as a result of the accident.

average tensile ductility values, measured by percent elongation,

- • .4 percent and 35.8 percent respectively for longitudinal and

transverse specimens. The longitudinal elongation values were approximately

four perc- ?her than the transverse values. This finding is in agreement

with the general observation that the tensile ductility of rolled steel

tends to be greater in the longitudinal direction than in the

transverse direction.

. : t i -area requirements are not specified in ASTM A212-B-65,

rut they : rovide a useful check of the elongation results since percent

•- duct: r.- in- area measurements are independent of the gage length of the

:im.er. . The trend for the reduction-in-area data given in Table II is

similar to those for the elongation data.

7 iltimate tensile strength data is consistent with the hardness

measurements and the results of the metallographic analyses. Using an

- irical relation between hardness and tensile strength [11], the

- asured nardness range of HRB 73 to 79 would correspond to an ultimate

tensile strength range of 64 ksi to 71 ksi, respectively. A photomicrograph of the cross-section of a transverse tensile specimen (shown

i' figure 9 ) points out some of the same microstructural variability as shown across the whole plate thickness in Figure 7. The microstructure

f the gage length region (Figure 9b) encompasses the transition region

retween zones 2 and 3 with a hardness range of approximately 74 to 77.

7h s hardness range corresponds to a range in ultimate tensile strength

of 65 ksi to 69 ksi, respectively. The measured average ultimate tensile

strengt.n of almost 68 ksi for both longitudinal and transverse specimens

falls within this predicted range.

7
The variation in hardness through the plate thickness will result in a similar variation in mechanical properties. Using the hardness-ultimate

tensile strength correlation, only that portion of the plate containing the

Zone 2 microstructure would be expected to meet the minimum ultimate tensile

strength requirement of ASTM A212-B-65. Hence, the plate clearly does not

meet the required minimum tensile strength of ASTM A212-B steel.

4.6 Bend Behavior

The results of the bend tests are given in Table III. Both the

longitudinal and transverse specimens, shown in Figure 10, are judged to

have passed the requirement of ASTM A212-B-65. There was no evidence of

cracking or surface crazing on either of the specimens tested.

4.7 Inclusion Content

The results of the inclusion content rating are given in Table IV.

The QTM area-percentage rating at an effective magnification^ of X100

indicates that the Winder plate sample had an overall average inclusion

content of 0.29 area percent (based on 100 fields). The observed number

of fields with an inclusion area equal to or greater than 0.5 percent was

found to be six. These results indicate that the Winder sample is cleaner

in comparison with the previously reported results for AAR M128-B steel [ 12]

.

The results of an earlier QTM inclusion analysis

^

of head and shell

plates of ASTM A212-B steel [4] showed average overall inclusion contents

of 0.19 and 0.13 area percent respectively. The observed number of fields

with inclusion areas equal to or greater than 0.5 percent were two and zero respectively, for the head and shell plates. Thus the inclusion content

rating results show that these two examples of ASTM A212-B steel were similar to each other and cleaner than the Winder head plate.

A further comparison can be drawn between the Winder results and values

reported^ for larger billet specimens from steel with a broad range of

strength levels [8]. The average inclusion area percent range reported was 0.10 to 0.38. The reported range for number of fields with inclusion areas

equal to or greater than 0.5 percent was 1 to 26. The Winder plate sample

lies between the middle and low ends of these ranges.

The effective magnification of the QTM system represents the actual

magnification of the image used by the internal electronic measuring

scale of the instrument. The image magnification or apparent

magnification, as measured on the visual display monitor, has no meaning because the monitor is not part of the measuring system.

' These QTM measurements were reported for an apparent magnification of

X338. This is equivalent to an effective magnification of X120 for

the particular instrument used.

(g) The reported data were obtained at an apparent magnification of X350

which was equivalent to an effective magnification of X100.

8
4 . 3 Impact Properties

4.8. 1 X i 1-IXict il itv Transition Temperature

The results of the drop-weight tests are given in Table V. ot the test specimens (pictured in Figure 11) shows that in both

men- tested at +-*0 F, the weld starter crack did not propagate to either

edge of the specimen surface. At 30 F and below, the weld starter crack

propagated to at least one edge of the specimen surface. According to the

: cri: ria of ASTM E208-69, the nil-ductility transition temperature is

4-30 F.

\ recent review of fracture toughness properties [14] from selected

pies as well as from both current and previously allowed

tank-car materials (including A212-B steel) reported +30 F as the highest

nil—duct transition temperature. Thus, the value of +30 F

r

- binder -ample is equal to the highest value reported for this group

of tank-car plates. This was observed despite the relatively low carbon

• • strength of this plate, both of which promote lower transition

temperatures

.

4.8.2 Charpy V-notch Tests

7: • results of the Charpy V-notch impact tests on both longitudinal

and verse specimens are given in Figure 12. Experimentally measured

values and the calculated curves are both shown for three fracture criteria:

energy absorption, percent shear fracture appearance, and lateral expansion.

The raw data and the results of calculations for the three plots are given

\, Tables Al through A6. The longitudinal (LT orientation) and

<7: 'rientation) specimens are oriented with the specimen axis

i - rpendicular, respectively, to the principal plate rolling

direction.

The results indicate that at temperatures between approximately

• - : the highest test temperature of 260 F, there is little variation

l t the r-erved behavior of either the longitudinal or transverse specimens.

In C .oper-shelf region, the percent-shear-fracture appearance, energy

- rpti n, and lateral expansion are at a maximum. For the transverse

- - -

, however, the upper-shelf energy absorption is only two thirds

that f the longitudinal specimens, 45 ft-lbs versus 72 ft-lbs, respectively.

7 is redo ted performance of the transverse specimens is further reflected

lower lateral expansion value of 54 mils compared to 72 mils for

longitudinal specimens.

At temperatures below about 180 F, the fracture of Charpy specimens

is associated with decreasing amounts of energy absorption, percent-shearfrazture appearance, and lateral expansion with decreasing temperature until

at some lower temperature all three criteria reach a minimum level called

the lower shelf. At temperatures between the upper shelf and the lower shelf,

there is a transition zone.

- 9 -
The results indicate that for each of the fracture criteria, the

transition zone lies in approximately the same range of temperature, a range

of 200 F between -20 F and +180 F. At temperatures below about 100 F, the

value of the fracture criteria are independent of specimen orientation while

at all higher test temperatures the energy-absorption and lateral-expansion

values are greater for the longitudinal specimens.

Photographs of selected fractured Charpy specimens are shown in

Figure 13. At temperatures above 40 F where shear fracture appearance

was about 15 percent or more, the fracture surfaces of both longitudinal

and transverse specimens were similar and contained regions of cleavage

fracture, fiberous fracture, and shear lips. Even at 260 F, the highest

test temperature used, both longitudinal specimens and transverse specimens

contained a slight trace of cleavage fracture, even though the energy

absorption and lateral expansion data indicated that the test temperature

was within the upper-shelf regime. Generally, the size of the shear lips

increased with increasing test temperature, and at a fixed temperature, were larger for longitudinal specimens than for transverse specimens.

Studies of shear fracture appearance from fractured Charpy

specimens taken from ASTM A212-B and AAR M128 steel shell plates [4,5]

revealed that both longitudinal specimens and transverse specimens

exhibited a large scale lamellar fracture appearance. This lamellar

appearance was not present in specimens of either orientation from an ASTM A212-B head plate [4] previously studied. Fractured Charpy specimens

from the Winder ASTM A212-B head plate, shown in Figure 13, do not contain

the massive lamellar appearance, in agreement with the previous observations

for an ASTM A212-B head plate.

The Charpy V-notch transition temperatures for longitudinal and

transverse specimens for the four head plates tested at NBS [7] are given

in Table VI for three commonly reported fracture criteria: 15 ft-lb energy

absorption, 15 mil lateral expansion, and 50 percent shear fracture

appearance. The ASTM A212-B plates have the highest transition temperatures

in the group with the Winder plate having the second highest values. The

15 ft-lb energy absorption and 50 percent shear-fracture-appearance transition temperatures for the Winder sample are all above 60 F and within the

normal service temperature range for tank cars. The absence of observed

strain-aging effects suggests that the high transition temperatures of the

Winder plate sample probably result from effects due to chemical composition

and grain size.

The extent of anisotropy resulting from cross-rolling of plate

materials can be assessed by the anistropy index [7], defined as the ratio of

the maximum shelf energy of transverse specimens of TL orientation to the

maximum shelf energy of longitudinal specimens of LT orientation. Using

this relationship, an isotropic material would have an index equal to one. Shell plates receive little cross-rolling and would be expected to have an anistropy index much smaller than one. The average index for all shell

plates tested at NBS [7] was found to be 0.50.

10
The Charpy V-notch upper shelf behavior of all head plates tested

r N3S , aiven in Table VII, shows that the Winder plate was the least

. •• 'r i c of the four head plates with an index of 0.63 compared to 0.66 for

Jther ASTM A212-B head plate and the average head-plate index of 0.68

(lowest index was 0.66) [7].

7 minimum Charpy V-notch upper-shelf energy absorption for all

specimen orientations parallel to the plate rolling plane occurs in specimens

of the transverse orientation. As seen in Table VII, the transverse upper-

:>o ray-absorption value for the Winder plate was lower than that of

the Ot jer ASTM A212-B head plate tested, 45 ft-lbs versus 55 ft-lbs, but r** . . irger than the values of 38 ft-lbs and 40 ft-lbs for the AAR M128

head plates tested. The longitudinal upper-shelf energy-absorption values

-how a similar relationship for these four head plates. Thus, these

rest m it the upper-shelf behavior for the Winder plate is inferior

to the ether ASTM A212-B head plate and slightly superior to the two AAR

M128 head plates.

4.9 General Discussion

irgese of this investigation was to determine if the head plate

saat from tank car SOEX 3033, involved in an accident near Winder,

informed with the applicable specification for tank-car

-.r : a 1 s ind to investigate the impact behavior of the plate.

ough the Winder sample satisfied most of the specification requiref r in ASTM A212-B steel, the strength requirements were not met. The

of the check chemical analysis indicated that although the Winder

- •

- rhemical requirements of ASTM A212-B steel, the carbon and

:

•. • levels are well below the maximum levels permitted. At reduced

. '

' two important elements often result in reduced strength

• • - ir ferr itic-pearlitic steels such as ASTM A212 steel. The

observation that tensile-strength and yield-point values were below the

mimmums, while the measured percent-elongation values were

the specification minimum, is consistent with the lower carbon

; manganese content measured in this steel. The observed hardness

f licy is consistent with the microstructure of the Winder plate and

trrrelates quite well with the measured tensile strength.

The Charpy V-notch ductile-to-brittle transition temperature of hotworked oarocr. steels, often characterized by the 15 ft-lb transition temperature :r ttt 50 percent shear-fracture-appearance transition temperature, is

rim nly determined by the steel chemistry and ferrite grain size. The

ferrite grair. size, as noted earlier, is strongly controlled by the prior

austenite grain size which is determined by the finishing temperature and

deoxidation practice and by the cooling rate through the transformation

temperature. Increasing the ferrite grain size raises the transition

temperature. The major influence of the steel chemistry on the transition

temperature of these tank car steels results primarily from changes in the

t arbor and manganese levels within certain ranges. Increasing the carbon

level raises the transition temperature while increasing the manganese level

lowers the transition temperature.

11
Metal lographic examination revealed the presence of a distinct microstructure consisting of Widmanstatten ferrite and a large prior austenite

grain size marked by ferrite boundaries. This microstructure characterizes

the two ASTM A212 head plates (Winder and Crescent City) examined at NBS

to date. Differences in transition temperature behavior between the two

ASTM A212-B head plates probably resulted from differences in steel

chemistry and mill processing procedures. Since neither of the A212-B

head plates were produced to fine-grain practice, the larger ferrite grain

size of the Crescent City plate probably resulted from a higher finishing

temperature. The Crescent City plate had a higher transition temperature

than the Winder plate and this behavior is consistant with the larger

ferrite grain size and higher level of carbon found in the Crescent City

plate (see Table VIII).

Although the two AAR M128 head plates previously tested at NBS were produced to fine-grain practice, the Belle plate had a more uniform microstructure with a much finer fe grain size indicating a probable lower

finishing temperature than the Callao plate. Although the microstructure of

the Callao-head plate sample was highly variable [12], the dominant features

were a coarser ferrite grain size and larger pearlite colonies compared to

the Belle sample. (h) Carbon levels were the same for both plates while the

Callao plate had a higher manganese level than the Belle plate. Thus the

lower transition temperature for the Belle plate appears to be primarily

a result of the finer ferrite grain size.

In this group of four head plates, the Crescent City plate with the

largest ferrite grain size and highest carbon content had the highest

transition temperature while the Belle plate with the smallest ferrite

grain size, a higher manganese content and lower carbon content, had the

lowest transition temperature. Based on comparisons between these four

head plates of two steel types, the carbon content, the manganese content,

and the ferrite grain size appear to be the most important factors influencing

the Charpy V- notch transition temperature behavior.

The reportedly [1] brittle fracture appearance of the failed Winder

head plate is consistent with the measured Charpy impact transition

temperatures. The Winder plate has a 15 ft- lb transition temperature of

66 F. This is 26 F above the tank car service temperature at the time of

the accident.

(h) The Callao head plate had an undesirable microstructure of unexpectedly

high variability probably resulting from improperly controlled

variables in the hot-forming process.
5. CONCLUSIONS

chemical composition of the Winder plate sample, as determined

by check chemical analysis, satisfied the chemical requirements of

AS TV. A.IS-B. The levels of carbon and manganese were well below

- maximum permitted levels and the absence of detectable levels

of aluminum or vanadium indicated that a course-grain steelmaking

practice was followed.

The results of tensile tests indicated that the Winder sample met

- minimum elongation requirement but failed to satisfy the

minimum tensile-strength and yield-point requirements for ASTM

AS12-B steel plates.

The low ultimate- tensile-strength and yield-strength values and

the generally observed sharp yield point in tensile tests suggests

that any plastic deformation of the plate resulting from the

accident was not significant and that strain aging had not occurred

in this plate after the accident.

Ultimate -tensile-strength and yield-strength values indicate little

anisotropy in the strength of the plate in the plane of the rolling

direction. Tensile ductility values, measured by percent elongation,

indicated that longitudinal ductility was greater than transverse

ductility.

results of bend tests indicated that both longitudinal and

transverse specimens passed the ASTM A212-B bend requirements.

- re suits of Charpy V-notch impact tests indicated that:

a. The 15 ft-lb transition temperature was 26 F above the ambient

temperature reported at the time of the accident.

b. The transition temperatures for three commonly used criteria

are above 44 F and were the second highest for all of the tankcar plates tested at NBS to date.

s. The transition from ductile to brittle failure occurs over

the same temperature range of about 200 F, from +180 F to

-20 F, regardless of specimen orientation for each of the

three fracture criteria.

d . The high impact transition temperatures for the three fracture

criteria are related to the lower manganese content and the

large prior austenite grain size and large ferrite grain size

observed in the microstructure.

13
6 . ACKNOWLEDGEMENT

The author wishes to express thanks to Dr. C. G. Interrante for his

helpful comments, and to Mr. D. E. Harne for his excellent contributions

to the metallographic, photographic, and mechanical testing portions of

this report. Thanks to Mr. C. H. Brady for the grain size measurements.

CONVERSION FACTORS

1 ksi = 6.89 MPa

1 ft-lb = 1.36 Joules

1 mil

o

t

c

= 0.025 mm

(t° - 32)

r o

14
References

Report from Inspector E. W. Timmons to Regional Director

. McLellen, Federal Railroad Administration, Department of

Transportation, 3666 EWT-523, April 28, 1975.

Original ph iphs courtesy of Mr. Q. Banks, Federal Railroad

Administration, Washington, D.C.

ie' r, E. Mechanical Metallurgy , McGraw-Hill Book Co.,

• City, 1961, pp. 557-562.

:a:errante, C. G. , Hicho, G. E. and Harne, D. E. "A Metallurgical

sis of Five Steel Plates Taken From A Tank Car Accident Near

'rescent City, Illinois," Report No. FRA OR&D 75-48, National

Bureau of Standards, March 1972, NTIS PB 250530.

In: mate, C. G. and Hicho, G. E. "Metallurgical Analysis of a

1 Plate Taken From a Tank Car Accident Near South Byron,

' rk," Report No. FRA OR&D 75-47, National Bureau of Standards,

October 1971, NTIS PB 250063.

• rr ate, C. G. , Hicho, G. E. and Harne, D. E. "A Metallurgical

i iv l s of Eleven Steel Plates Taken From A Tank Car Accient Near

, ''issouri," Report No. FRA OR&D 75-49, National Bureau of

Standards, September 1972, NTIS PB 250544.

rr .nte , C. G. "Impact Properties of Steels Taken From Four Failed

Tir. rs,’ Report No. FRA OR&D 75-51, National Bureau of Standards,

June 1976.

•i ~ege, R. A., Forgeng, W. D. Jr., Stone, D. H. and Alger, V. V. , r

3

cleanl iness of Steel - A New Quantitative TV Rating Method,"

ASTM ST? 480, American Society for Testing and Materials, 1970,

pp. 249-272.

5 roc son, H. I. , Decomposition of Austenite by Diffusional Processes , i. '. r

. Zackay & H. I. Aaronson, Interscience Publishers, 1962,

pp. 387-545.

Atlas of Isothermal Transformation and Cooling Transformation Diagrams,

American Society for Metals, 1977.

Arm;/- Navy Approximate Hardness Tensile Strength Relationship of Carbon

and Low Alloy Steels (AN-OO-H-201)

.

2) Interrante, C. G. , Early, J. G. , and Hicho, G. E. "Analysis of Findings

of Four Tank-Car Accident Reports," Report No. FRA OR&D 75-50,

National Bureau of Standards, Jan. 1975, NTIS PB 251097.

15
References (continued)

(13) Early, J. G. , "Elevated-Temperature Mechanical Behavior of a CarbonManganese Pressure Vessel Steel," J. Engineering Materials and

Technology, 99, 1977, pp. 359-365.

(14) Eiber, R. J. and Olson, L. L. , "Material Study on Steels Used in

Current and Former Tank Car Construction and From Cars Involved

in Accidents," AAR Report RA-03-5-33, August 21, 1975.

16
Table I Chemical Composition of the Winder Sample

Percent by Weight

Element

Specification

ASTM A212-65-B

Ladle Analysis Check Analysis

Carbon

Manganese

Phosphorus

Sulfur

Silicon

Copper

Nickel

Chromium

Molybdenum

Vanadium

Aluminum

0.31 max. 0.24

0. 90 max. 0.73

0 . 04 max

.

<0.005

0.05 max. 0.026

0.13/0.33< b) 0. 26

(c) <0.05

(c) <0. 05

(c) 0.07

(c) <0.05

(d) <0. 01

(d) <0. 01

Carbon was determined by combustion-conductometric analysis; all

jther elements were determined by emission spectroscopy.

(b)

Check analysis.

(c)

Element not specified.

(d)

^lerr.er.t not specified, either fine-or coarse-grain practice allowed.



Table III Bend Behavior of Winder Sample

Orientation

Longitudinal

Transverse

Ratio of Bend

Diameter to Thickness Angle of

d/t Bend Comments

2 180° Passed, no evidence

of crazing or cracking

2 180° Passed, no evidence

of crazing or cracking

For all tests, w/ t = 4.

-a

i’

®agcu

-a—2

O'

r-~ O

Cfci

Ql£

C/5

Umwo3

coa

U ii g c

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M

u

a

co3 -C CT E-

<rmo

“3 4-1 c CG

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G

w rH

O

U-4

G

G

—> o n 

« •tc Cb 3 m

00

G

—

. c G IM U o M o G A

iJ < i—

5 C uG .c

GG 0 X5 i_i u

kJ •H s —* < W (0 3 3 3 Z kJc O Q

CJ

M c G o CO » -—\ •*4 O' G C co CO c C O — 3 •»4 .2 •H —| 44 a kJ G U G *rH *rH *r4 C B .c CO B, M H o z 2

E- <r

a*m

CM

O cr c*>

<r

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co c co 0 0 3

jts tj ai

CJ *H *H H CO JG O

i~>

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to[[l
Table V Drop-Weight Test Behavior of Winder Plate

Spec itnen

Code

Test

Temperature, F Comments

N1 +10 Specimen cracked into two pieces

N4 +20 Starter crack propagated to both

edges of specimen

N6 +30 Starter crack propagated to one edge of specimen

N8 +40 Starter crack did not propagate

to either edge of specimen

N9 +40 Starter crack did not propagate

to either edge of specimen

Nil-Ductility Transition Temperature = +30F
'[[[t[[c[[[
Table VI Charpy V-notch Impact Transition Temperatures

For Four Head Plate Steels Tested at NBS

Transition Temperature, F

15 f t— lbs 15 mil 50 percent

Steel Plate Specimen Energy Lateral Shear

Type Identity Orientation Absorption Expansion Fracture

A212-B Winder Long. (LT) 66 50 111

Trans. (TL) 67 44 100

A212-B

(a)

Crescent City Long. (LT) 92 72 137

FRA

Trans. (TL) 84 69 143

AAR Callao

^

Long. (LT) 56 41 86

M128 K-l

Trans. (TL) 72 64 98

AAR Belle

(c)

Long. (LT) -47 -43 -11

M128

Trans. (TL) -49 -50 -21

(a)

Reference [A]

(b)

Reference [6]

(c)

Reference [7]
rrr*r\[
Upper

Shelf

Energy

CO i— Z

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Cl

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cn xCO r-s •n H

lj _J CL

Lio

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OX iO vO rs vO o O o d

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[[[[[[[[[

[l[[l
igure 1. Photograph of Tank Car SOEX 3033 at the Accident Site

Near Winder, GA.

The A-head, containing the site of impact, is shown.

Original color photograph courtesy of Q. Banks, FRA-DOT.

I

Figure 2. Close-up of A-head, Tank Car SOEX 3033.

i

I

The plate sample submitted to NBS for study was taken

from a relatively undamaged region, shown at A.

Figure 3. Winder Plate Sample.

Principal plate rolling direction determined with respect

to an arbitrary reference line scribed on the plate

surface, marked as REF. Chemistry and metallographic

samples were taken from locations marked CHEM and MET,

respectively.

fl

igure 4. Winder Plate Sample Showing Location and Orientation of

Test Specimens.

Principal rolling direction of the plate and arbitrary

reference line are shown marked as RD and REF, respectively.
.
Figure 5. Schematic Showing the Three Mutually Perpendicular Planes

Associated with the Rolling Direction in a Plate.

The A plane is parallel to the plate surface. The C plane

contains an arrow which indicates the plate rolling

direction or longitudinal direction.
f
Figure 6. Representative Photomicrographs of Inclusions on Two

Orthogonal Planes

a. Longitudinal or C plane

b. Transverse or B plane

Unetched Mag. X 100

Zone 1

Zone 2

Zone 3

OUTSIDE

PLATE SURFACE

H R B

i- —' .-r

^<3 /'>y 'VfP fe'- ** ^

r* v ^v ^-.fi <

'jrt&fr' **$'*.& t

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MIDTHICKNESS

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' •:; "r V

INSIDE

PLATE SURFACE

Zone 3

Zone 2

Zone 1

-re 7. Montage of Microstructure Through Cross-Section of the Plate.

Hardness values are representative of the locations shown.

Etch: 5% Nital Original Micrographs Mag. X 40
I[[r-Ir-L
- igure 8. Photomicrographs of Typical Microstructure from Zones 2 and 3.

a. Zone 2 Pearlite colonies, surrounded by ferrite grains on prior austenite grain boundaries, containing

Widmanstatten ferrite.

b. Zone 3 Large amounts of ferrite mask prior austenite grain

boundaries. Widmanstatten ferrite has greatly

thickened.

Etch: 4% Picral Mag. X 100
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a. b.

Bend Test Specimens

a. Longitudinal specimen

b. Transverse specimen

Figure 10.

Figure 11. Drop-Weight Test Specimens.

Nil-Ductility Transition Temperature (NDT

temperature) = +30 F

i

SPECIMEN IDENTIFICATION

g-> 6 SPECinENS. LT ORIENTATION.

17 SPECIMENS. TL ORIENTATION.

TEST TEMPERATURE (F)

Figure 12a. CHARPY I MPRCT TEST RESULTS FOR HEAD PLATE SPECIMENS

TAKEN FROM ASTM A212 STEEL PLATE S
I
X

SHEAR

FRACTURE

APPEARANCE

25.0

37

.S

50.0

62. S

75-0

87.

o SPECIMEN IDENTIFICATION

O

°-| O 6 SPECIMENS. LT 0RIENTATI0N. ffl

TEST TEMPERATURE (F)

Figure 12b. CHARPY IMPACT TEST RESULTS FOR HEAD PLATE SPECIMENS

TAKEN FROM ASTM A212 STEEL PLATE S

LATERAL

EXPANSION

(NILS)

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80. o SPECIMEN identification

' 6 SPECIMENS. LT OR l EN TflT I 0N . + 17 SPECIMENS. T L OR I ENTflT I 0N .

TEST TEMPERRTURE (F)

280.0

Figure 12c. CHflRPY IMPACT TEST RESULTS FOR HEAD PLATE SPECIMENS

TAKEN FROM ASTM A212 STEEL PLATE S

Sample

Energy

Test

No.

Abs.

(ft-lb)

Temperature

CM\

CM

CM CM\

rH CO

co rr r~

CTl I—I CM CM

00 CO ^

CM CO 'cf ^ in in^

CM CO CTi in lO CM in 00 rH

CM 1—iH H CM co CO CO CM ro co

E-* E" Eh Eh Eh Eh Eh Eh Eh Eh Eh CO CO CO CO CO CO CO CO CO co CO

Figure

13.

Fracture

Appearance

of

Selected

Charpy

Specimens

Taken

from

the

Winder

Sample.

Appendix A, Table Al

CHARPY IMPACT TEST RESULTS FOR HE AO PLATE SPECIMENS

TAKEN FROM A STM A2 1 2 STEEL PLATE S

CALCULATIONS FOR ENERGY ABSORPTION DATA OF

6 SPECIMENS. LT ORIENTATION.

SPEC IMEN TEMPERATURE ( F

)

OBSERVED ENERGY

ABSORPT lON(FT-LB)

CALCULATED ENERGY

ABSORPTION! FT -LB)

SLA -120.0 1.00 1 • 0

SL 1 0 • 0 3.50 3. 6

SL7 40.0 7.80 3. 5

SL 1 4 80. 0 19.50 19.9

SL I I 120.0 37.80 39.

5

S. 1 J lt>0.0 60.50 60.3

0- I 212.0 72.00 71.4

40-2 2 12.0 72.00 71 .

SCO 260.0 71.50 71.8

TRANSITION REGION CALCULATED VALUES

ENERGY CALCULATED / TEMPERATURE CALCULATED ENERGY

ABSORPT I ON TEMPERATURE (

) / (F > ABSORPTION! FT-LB)

5.0 1 5.9 / 20 .0 5.5

10.0 47.3 / 25.0 6.1

15.0 66.2 / 30.0 6.8

20.0 30.4 / 35.0 7.6

25.0 92. 1 / 40.0 8.5

30.0 102.4 / 45.0 9.5

35.0 111.9 / 50.0 10.6

40.0 1 20.8 / 55.0 11.3

45.0 129.6 / 60. 0 13.2

50 • 0 138.5 / 65.0 14.6

55.0 147.8 / 70*0 16.2

60.0 158. 3 / 75.0 18.0

65.0 171.3 / 80.0 19.9

70 . 0 193.8 / 85.0 2 1 .9

/ 90.0 24.0

/ 95.0 26.3

/ 100.0 28.8

/ 105.0 31.3

/ 110.0 34.0

/ 1 15.0 36.7

Appendix A, Table A2

C H ARPY IMPACT TEST RESULTS FOR HEAD PLATE SPECIMENS

TAKEN FROM A ST M A212 STEEL PLATE S

CALCULATIONS FOR LATERAL EXPANSION DATA OF

b SPECIMENS. LT ORIENTATICN.

SPECIMEN TEMPERATURE (F ) OBSERVED LATERAL CALCULATED LATERAL

EXPANSION (MILS) EXPANSION (MILS)

SLA -120.0 • 00 . 2

SL 1 0 . 0 4.50 5. 1 SL7 40.0 12.00 12.4

SL 1 A 80 .

0

26.50 25.8

SL 1 1 120.

0

43.50 44. 7

SL 1 3 160.0 61.00 62.2

AO- 1 2 12.0 72.50 71.2

40-2 212.

0

73.00 71.2

SL b 260.0 70.00 71.8

TRANSITION REGION. CALCULATED VALUES

lateral CALCULATED / TEMPERATURE CALCULATED LATERAL

EXP ANS I ON< M ILS) TE MPE R A T URE ( F

)

/ (F ) EXPANSI ON( MILS)

5.0 -1.1 / • 0 5. 1 10.0 29.6 / 5.0 5.8

15.0 49.6 / 10.0 6.5

20.0 65.0 / 15.0 7.3

25 . 0 78. 1 / 20.0 8.

30 . 0 89.6 / 25.0 9. 1 35.0 100.3 / 30.0 10.1

40.0 110.5 / 35.0 11.2

45 .

0

120.6 / 40.0 1 2.4

50 . 0 130.8 / 45.0 13.7

55.0 14 1.6 / 50.0 15.1

60 . 0 1 53.8 / 55.0 16.6

65 .

0

169.1 / 60.0 18.3

70 .

0

195.7 / 65.0 20. J / 70.0 21 .8

/ 75.0 23.8

/ 80.0 25.8

/ 85.0 27.9

/ 90.0 30.2

/ 95.0 32.5

Appendix A, Table A3

CHARPY IMPACT TEST RESULTS FOR HEAD PLATE SPECIMENS

TAKEN FROM A ST M A2 1 2 STEEL PLATE S

CALCULATIONS FOR SHEAR FRACTURE APPEARANCE DATA OF

6 SPECIMENS. LT ORIENTATION.

SPEC I MEN TEMPERATURE (F) OBSERVED

FRACTURE

SHEAR

( x)

CALCULATED SHEAR

FRACTURE (%)

SLA -120.0 .00 • 1 SL l 0 . 0 5.00 4.

9

SL7 40.0 11.00 13.4

SL I A 80.0 40.00 30.5

SL 1 1 120.0 49.00 56. 3

SL 13 160.0 84.00 81.7

A3- l 212.0 96.0 0 96. 1 AO-2 2 12.0 96.00 96. 1 SL 6 260.0 1 00.00 97. 3

TRANSITION REGION • CALCULATED VALUES

X SHEAR CALCUL ATED / TEMPERATURE CALCULATED SHEAR

FR ACTURt TEMPERATURE! F

)

/ (F ) FRACTURE! X)

2 . 0 -29.9 / -20 .

0

2.7

5.0 1 • 1 / -10.

0

3. 7

10.0 27.7 / . 0 4.9

15.0 45. 1 / 10.0 6.4

50 . 0 111.0 / 20.0 8.2

85.0 166.9 / 30*0 10.6

90.0 179.9 / 40.0 1 3.4

95.0 201 .9 / 50.0 16.7

98.0 260.0 / 60.0 20.7

/ 70.0 25.3

/ 80.0 3 0.5

/ 90.0 36.3

/ 100.0 42.6

/ 110.0 49.3

/ 120.0 56.3

/ 130.0 63.2

/ 140.0 69.9

/ 150.0 76.2

/ 160.0 81.7

/ 170.0 86.3

Appendix A, Table A4

CHARPY IMPACT TEST RESULTS FOR HEAD PLATE SPECIMENS

TAKEN FROM AST M A212 STEEL PLATE S

CALCULATIONS FOR ENERGY ABSORPTION DATA OF

17 SPECIMENS. TL ORIENTATION.

SPECIMEN TEMPERATURE ( F ) OBSERVED ENERGY CALCULATED ENERGY

ABSORPT IONIFT-LB ) ABS OR PT I ONI F T -L B

)

ST 22 -120.0 1.30 1 .

3

ST l 6 • 0 3.50 4.0

ST 25 20.0 6.00 5. 9

ST 1 9 40.0 9.50 8.9

ST 1 60.0 1 7.50 13.1

ST 1 S 60.0 13.00 13. 1 ST 3b bO.O 1 0.30 1 3. 1 ST 2 7 80.0 12.90 18.6

ST 2 b 80.0 24.50 18.6

ST 3 2 100.

0

27.00 25. 1 ST 6 100.0 27.50 25. 1 ST3S 120.0 28.30 31.8

ST 3 3 120.0 32.50 31.8

ST l 1 140.0 36.50 37. 7

ST 34 140.0 36.50 37.7

ST 2 ti lbO. 0 44.50 41.8

ST 7 180.0 44.20 44. 1 T-2 212.0 45.00 45. 1 T-3 212.

0

45.00 45. 1 T-4 212.0 46.50 45. 1 ST 3 1 260.0 45.00 45.

TRANSITION REGION. CALCULATED VALUES

ENERGY CALCULATED / TEMPERATURE CALCULATED ENERGY

ABSORPT I UN TEMPERATURE I F ) / (F ) ABSORPTION! FT-lB)

5.0 11.7 / 20.0 5.9

10.0 4 5.9 / 25.0 6.6

15.0 67.4 / 30.0 7. 3

20.0 84.5 / 35.0 dm 0

25.0 99.8 / 40.0 8.9

30.0 114.6 / 45.0 9.8

35.0 130.4 / 50 .0 1 0.8

40.0 150.0 / 55.0 1 l .9

45.0 202.4 / 60.0 13.1

/ 65.0 14 .4

/ 70.0 15.7

/ 75.0 17.1

/ 80.0 18.6

/ 85.0 20.2

/ 90.0 2 1.8

/ 95.0 23.4

/ 100.0 25 .

/ 1 05.0 26.8

/ 110.0 28.5

/ 115.0 30.1

Appendix A, Table A5

C^ARPr IMPACT TEST RESULTS FOR HEAD PLATE SPECIMENS

TAKEN FROM A ST M A2 1 2 STEEL PLATE S

CALCULATIONS FOR LATERAL EXPANSION DATA OF

17 SPECIMENS. TL ORIENTATION.

SPECIMEN TEMPERATURE (F) OBSERVED LATERAL CALCULATED LATERAL

EXPANSION (MILS) EXPANSION (MILS)

ST22 -120.0 • 00 • 2

ST 1 8 • 0 5.00 6 • 1 ST 25 20.0 11.50 9. 4

ST 1 9 40.0 13.50 1 3. 8

ST I 60 .

0

22.50 19. 5

ST 1 5 60.0 21.00 19. 5

ST 36 60.0 14.00 19. 5

ST 2 7 80.0 19.00 26. 4

ST 26 80.0 33.00 26. 4

ST 3 2 100.0 36.50 33. 8

ST 6 100.0 35.00 33. 3

ST 3 5 120.0 36. 00 41 • 0

ST 3 3 120.0 4 1.50 4 1 . 0

ST 1 1 140.0 45.00 47. 0

ST 34 140.0 47.00 47. 0

ST 2 8 160.0 55.00 51 . 0

ST7 180.0 54.00 53. 2

T-2 212.0 52.00 54. 2

T-3 212.0 52.00 54. 2

T-4 2 12.0 50.00 54. 2

ST 3 l 260.0 58.50 54. 3

TRANSITION REGION . CALCULATED VALUES

LATERAL CALCULATED / TEMPERATURE CALCULATED LATERAL

EXPANSI 0N< MILS) TEMPER ATURE ( F

)

/ (F ) EXPANSIUNIM ILS)

5.0 -3.9 / • 0 6.1

10.0 23.2 / 5.0 6.3

15.0 44.5 / 10.0 7.6

20.0 61.5 / 15.0 8.5

25.0 76.2 / 20.0 9.4

30.0 89.8 / 25.0 10.4

35.0 1 03.2 / 30.0 11.4

40 • 0 117.1 / 35.0 12.6

45.0 132. 7 / 40.0 13.8

50.0 153.8 / 45.0 15.1

/ 50.0 16.5

/ 55.0 18.0

/ 60.0 19.5

/ 65.0 21.1

/ 70.0 22.8

/ 75. 0 24.6

/ 80.0 26.4

/ 85. 0 28.2

/ 90.0 30.1

/ 95.0 31.9
tL
Appendix A, Table A6

CHAKPY IMPACT TEST RESULTS FOR HEAD PLATE SPECIMENS

TAKEN FROM A ST M A2 1 2 STEEL PLATE S

CALCULATIONS FOR SHEAR FRACTURE APPEARANCE DATA OF

17 SPECIMENS. TL ORIENTATION.

SPECIMEN TEMPERATURE ( F i OBSERVED SHEAR CALCULATED SHEAR

FRACTURE (%> FRACTURE (X)

ST22 -120.0 • 00 • 1 ST l S • 0 3.00 6.7

ST 25 20.0 22.00 11.1

ST i 9 40.0 25. 00 17.5

ST 1 60.0 43.00 26. 1 ST 1 S 60 • 0 37.00 26 . 1 ST 36 60.0 6.00 26. 1 ST 2 7 80.0 36.00 37. 1 ST 26 80.0 50.00 37. 1 ST 32 100.0 49.00 49. 9

ST to 100.0 53.00 49.9

ST 35 120.0 48.00 63.4

ST 3 3 120.0 75.00 63.4

ST 1 1 140.0 77.00 75. 7

ST 3 A 140.0 67.00 75.

ST 2 8 160.0 88.00 85.4

ST 7 180.0 95.00 91.5

T-2 212.0 95.0 0 95. 4

T— 3 212.

0

95.00 95.4

T

212.0 95.00 95. 4

ST 3 l 260.0 1 00.00 96.0

TRANSITION REGION, CALCULATED VALUES

% SHEAR CALCULATED / TEMPERATURE CALCULATED she

FRACTURE TEMPERATURE ( F I / (F ) F R AC TURE (

) 2.0 -4 1.9 / -40 .

0

2.

5.0 -I 1 . 1 / -25.0 3.4

10.0 15.6 / - 10.

0

5.2

15.0 33. 0 / 5.0 7.7

50.0 100. 1 / 20.0 11.1

85.0 159.1 / 35.0 15.7

90.0 173.8 / 50.0 21.5

95.0 205.2 / 65.0 28.7

98 .

0

260. 0 / 80.0 37.1

/ 95.0 46 • 6

/ 110.0 56.7

/ 125.0 66 • 6

/ 140.0 75.7

/ 1 55. 0 83.3

/ 170.0 88.9

/ 185.0 92.5

/ 200.0 94.6

/ 215. 0 95.5

/ 230.0 95.9

/ 245.0 96.0

NBS-1I4A l»EV 7-tji

U.s. DEPT. OE COMM 1. PUBLICATION OR REPORT NO. 2. Gov’t Accession 3. Recipient’s Accession No. , BIBLIOGRAPHIC DATA No. SHEET

4 . TITLE AND SUBTITLE

ICAL ANALYSIS OF AN ASTM A212-B_STEEL TANK CAR

HEAD PLATE

' *' *

REPORT NO. 9

5. Publication Date August 1978

6. Performing Organization Code

7. AUTHOR(S)

J. G. Early

8. Performing Organ. Report No.

9. Ef A FOR MING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 5620413

11. Contract/Grant No.

' Sp -ti > or i n g Organic ation Name and Complete Address (Street, City, State, ZIP)

Federal Railroad Administration

Department of Transportation

Washington, D.C. 20590

13. Type of Report & Period Covered

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

200-word or less tactual summary of most significant in formation. If documen t includes a significant

f •' /-,> v^v or literature survey, mention it here.) A metallurgical evaluation of a steel head plate

sample was requested by the Federal Railroad Administration to determine if the sample

conformed with the appropriate specification for tank car materials and to determine the

test behavior of the plate sample. The head plate was reportedly produced to

specification ASTM A212-65, Grade B steel. The results of laboratory check chemical

analyses indicated that the plate sample met the chemical requirements of ASTM A212-65,

Gr^de B steel. The results of ambient-temperature bend tests and tensile tests showed

that the plate sample satisfied both the bend requirements and the tensile elongation

requirements but failed to meet the minimum ultimate tensile strength and yield point

requirements. The results of metallographic analyses revealed substantial variation in

tne ncrostructure in the plate thickness direction. The observed coarse prior austenite

jrair. size and large ferrite grain size is consistent with the coarse-grain steelmaking

prartice aLoved tor ASTM A212 steel and a high finishing temperature during fabrication.

::ard'.i5s proriles of the microstructure correlated with the measured tensile strength

properties. The nil-ductility transition temperature was determined to be 30 F, equal

to the nig’nest value recently reported for a group of tank car plate samples. The

r - su *- s Cnarpy V-notch tests established that the transition temperatures measured

~ - r -rree widely used fracture criteria were all above 44 F and within the expected tank

jear service temperature range. The high transition temperatures are belated co both the coarse prior austenite grain size and large ferrite grain size observed in the

' i cro s

t

t

_

cture and the steel chemistry.

" ' x to twelve entries, alphabetical order, capitalize only the first jotter of the first key word unless a proper name, separated by semicolons ) A-rj.:: A212 steel; Charpy V-notch impact properties; head plate; nil-ductility

transition temperature; railroad tank car; tensile properties

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