Reproducibility of keyhole charpy and tear test data on laboratory heats of semikilled steel

Fifth

PROGRESS REPORT (Project SR-i 10)

on

REPRODUCIBILITY OF KEYHOLE CHARPY AND TEAR TEST DATA ON

LABORATORY HEATS OF SEMIKILLED STEEL

by

R. H. FRAZIER, F. W. BOULGER and J. W. SPRETNAK Battelle Memorial Institute

Transmitted through

NATIONAL RESEARCH COUNCIL'S COMMITTEE ON SHIP STEEL

Advisory to

SHIP STRUCTURE COMMITTEE

Division of Engineering and Industrial Research National Academy of Sciences - National Research council

Washington, D. c.

LABORATORIUM VOOR

SCHEEPSCONSTRUCTIES

FEBRUARY 7, 1955 SERIAL NO, SSC-83

0107

SHIP STRUCTURE COMMITTEE

February

7, 1955

Dear Sir:

As part of its research program related to the im-provement of hull structures of ships, the Ship Structure Committee is sponsoring an investigation of the influence of chemical composition and deoxidation on the notched bar properties of ship plate steels at Battelle Memorial

In-stitute. A paper covering portions of this work was presented at the Siposium on Effect of Temperature on the Brittle Be-havior of Metals with Particular Reference to Low Temperatures

held. at the annual meeting of the American Society for Testing Materials, Atlantic City, June 28--30,

_1953.

This paper,

entitled "Reproducibility of Keyhole Charpy and Tear-Test Data

on Laboratory Heats of Semikilled Steel" by R. H. Frazier, J. . pretnak and F. W. Boulger, constitutes Part I of the

attached report, SSC-83, the progress report on the project. Part II of the report describes the results of later calcula-tions.

The project is being conducted with the advisory assistance of the Committee on Ship Steel of the National

Acedemy of Sciences-National Research Council.

Comments concerning this report ar solicited and

should be addressed to the Secretary, Ship Structure Committee. This report is being distributed to those individuals

and agencies associated with and interested in the work of

the Ship Structure Committee.

Yours sincerely,

Rear Aarnirai, U. S. Coast Guard Chairman, Ship Structure

Comm i t t e e

MEMBER AGENCIES: ADDRESS CORRESPONDENCE TO:

BUREAU OP SHIPS. DEPT. OP NAVY SECRETARY

MILITARY SEA TRANSPORTATION SERVICE. DEPT. OP NAVY SHIP STRUCTURE COMMITTEE UNITED STATES COAST GUARD. TREASURY DEPT. U. S. COAST GUARD HEADQUARTERS MARITIME ADMINISTRATION. DEPT. or COMMERCE WASHINGTON 25. D. C.

FIFTh

Progress Report

(Project SR-ib)

on

REPRODUCiBILITY OF KEYI-IOLE CHARPY AND TEAR TEST DATA ON LABORATORI HEATS CF SEHIKILLED STEEL

by

R0 H0

Frazier, J W0 Spretnak and F0 W0 Boulger

Battelie Memorial Institute

und e r

Department of the Navy

Bureau of Ships NObs3239

BuShips Project No0

_NS-Oli-078

for

TABLE OF CONTENTS

Pa g e

PART I

Reprint, Symposium on Effect of Temperature on the

Brittle Behavior of Ieta1s with Particular Ref-erence to Low Temperatures, American Society for Testing }'Iaterials, June

28-30, 1953.

PART II

Suiriniary i

1l:aterials 2

Testing Procedures 2

Expected Uncertainty in Tear Test Transition

Temperatures Q G O O O O Q 8

Correlation Analysis of Tear Test Data

Correlation of Charpy and Tear Test Transition

Temperatures 17

LABOATORUM VOOR

SCHEEPSCONSTRUCTES

PART II

REPRODUCIBILITY OF KEYHOLE CHARPY A

DATA Ql LABORATORY HEATS 0F SIKILLED

SUMÌ4ARY

Part I of this report

concluded

that the method of defin

Ing the tear test transition temperature should be reconsidered0

Later calculations, based on 130 observations on Type A steel

indicate the advantages of defining the transition temperature

on a probability basis0 If twenty specimens are tested at temperatures covering the transition zone9 the transition tem.

perature, based on equal probabilities of ductile and brittle

fractures, can be determined with a standard deviation of 606°F0

The comparable limit of uncertainty for

transition

temperatures

corresponding to the highest temperature where at least one

brittle specimen is found when testing groups of four, is 11F0

A large number of tear test data were used to establish

the relationships between transition temperatures defined In

different ways0 The study indicates that transition tempera

tures, based on 5O per cent brittle fracture texture, are

equivalent to those based on p = 05 for brittle specimens

Both give lower transition temperature values than the Kahn-Imbeinbo criterion0

Even when tear test transition temperatures are defined

on a probability basis, they do not correlate very precisely

2

transition temperature, based on data obtained in the other

type of test, are likely to be in serious error0

MATERIALS

Data obtained on

₉₅

plates of steel were used to compare different criteria for defining the transition temperature in

Navy tear tests0 The 3/+-in0 plates were rolled from 2-3- experi

mental openhearth ingots0 The steels represented two combina

tions of carbon and manganese which gave tensile strengths of

approximately 62,5OO lb0 per sq0 in The nominal compositions

were O2O% carbon, O76% manganese, and O22% carbon and

o1+5%

manganese0 The steels varied in aluminum contents and had been

rolled at different finishing temperatures0 The effects of the

variations in composition and processing treatments are de

scribed in a separate

report*o

The compositions of the plates tested during this study

are listed in Table 70

The steel plants supplied 3/+-in0 plates

and i 3/+-in0 slabs0 The latter were rolled to 3/-iin0 plates

in the laboratory, using finishing temperatures of i65'O0 1850°, and 20500F0

TESTING PROCEDTJRES

Tests were made on keyhole Charpy bars taken parallel to

the rolling direction of the plates and notched through the

TABLE 70 COMPOSITIONS AND ROLLING TEMPERATURES OF EXPERIMENTAL OPEN-HEARTH STEELS

*The aluminum values for the last eight steels are for acid soluble amounts; the

others

are for total aluminum contents. Vi 0.26 _o.1+5 0.008 0.032 0.09

0003

V2 _0.27 0.1+5

_0.009

0.032 0.07 0.007 V3 _0.28 o1+6 _{0.009 0.032 0.09} 0.011 V1f _0.29 0.1+5 0.009 0.032 0007 0.018 V5 0.21 0.67 0.012

0.033

0.07

0.002 V6 _{0.19 0.67} 0.011 0.032 0.07 0.007 V? 0.22

0.67

0.012 0.033 0.07 00011 0.19 0.66 0.011 0.033

o.o8

0.015 Wi 0.23 0.52 0.013 0.037 0.09 0.001 W2 0,23 0.52 0.011 0.037 0.10 O0O1+ W3 0.23 0.52 0.012 0.01+1 _{0.09 0.005} W1+ _{0023 0.52 0.0i3}

0.039

0.10

_0.025 W5 0.23

0.78

0.012 0.025 0.09 0.001 W6 0.22 0.80 0.013 0.026 0008 0.003 W7 0.20 0.80 0.012 _0.025 0.08 0.007 w8

0.21

₀₀₇₈

₀₀₀₁₃

0.026

o.o8

_0.032 Z1 ₀₀₁₉

0.67

0.012

0.O8

0.01+0 _0.002 Z2 ₀₀₁₉ 0.68 0.013 0.028 0.01+0 0.001 Z3

o.i8

0068

0.012

_0.027 0.01+0 0.013 0.19

0068

_0.013

0.027 0.01+0 0.01+1+

Z5

0.27 0.50 0.017 0.01+1

0.057

0.003

Z6

_0.27

_0.51

_0.017 0.01+2 _0.058 0.002 Z7 0.27 0.1+9 _0.017 0.01+2 _{0.058 0.009} z8 0.27 0.50 0.018 0.01+2 _{0.058 0.030}

Heat Chemical Composition, per cent

plate thickness0 Four specimens from each plate were broken

at each temperature, and the Charpy transition temperature

was taken as the temperature at which the average curve crossed

the 12 ftC-lb level0 Tear test specimens were also taken parallel

to the rolling direction0 Four tear specimens were broken at

temperatures 100F apart throughout the transition zone0 This

practice permitted the tear test transition temperature to be

defined by three different criteria0 These definitions for transition temperature are

l The highest temperature at which one or more of four

specimens exhibits a fracture area with less than 50 per cent shear texture0 This is the definition used by Kahn and Imbembo(5D0

2 The temperature corresponding to 50 per cent shear

texture when average percentages of shear texture

in fractured surfaces are plotted against testing

temperature0 This definition is used by some steel companies

30 The temperature at which the probability of brittle specimens is 05 when brittle specimens are defined

as those having less than 50 per cent shear texture

on the fractured surface. The reasons for suggesting this criterion are discussed in Part I of this report0

The results of the notched bar tests are summarized in

- 5

TABLE 8

TRkNSITIOJ TPEATLJFS

IN N0TCH BAR TESTS

Wi W2 W3 1700 1750 1750 1700 l7 +2 15

80

90 100 80

80

85 91+ 68 8]

87

98

70

W5

1700

-8

110

103 108 W6 ₁₇₂₅ J+ ₁₁₀ 101+ ₁₀₅ W7 1800 _-1+3 80 70 71 W8 ₁₇₂₅

₃₇

80 51+

₅₇

Wi 1650 -31f 50 1+5 1+0 W2 1650 -17 1+o W3 1650

-33

70 1+8 1+9 1650 31+ _{70 58}

₅₉

1650

0

30

36

35

W6 ₁₆₅₀ -1+3 1+0 1+6 W7 1650 -63 60 50 ₅₃ W8

₁₆₅₀

-62

30 20 ₂₃ Wi ₁₈₅₀ -10 80

₇₃

61+ W2

₁₈₅₀

-io

60

₆₇

₅₅

W3

1850

_-38

80

58 63 w1+

i85o

-31

70

71

6 W6

₁₈₅₀

_-17

₆₀

66

₆₅

W7

1850

J+9

60

59 57 w8

₁₈₅₀

J+o

39

LfO Wi

₂₀₅₀

i8

6e

35

1+0 W2

₂₀₅₀

-11+ 70

68

₆₅

W3

2050

-25

60

57

₅₅

2050

.22

70

63 58

2050

-13

100

62

₇₅

W6

₂₀₅₀

-5

₇₀

₇₃

₆₆

W7

₂₀₅₀

-37

70

₅₉ 61+ W8

₂₀₅₀

JO

₇₀

₅₀

₅₃ 12 ft-lb Keyhole

Heat Rolling Charpy Transi-.

6=

TABLE 8

(C0NTINIJ)

Test

Transition Tern

°F

12 f t-1b Keyhole

Navy Tear

Heat

Rolling

Charpy Transi=

50% 50

No0

Teinp,°F

tion Temp,°F

Kahn Brittle Fracture Brittle Tests

Vi

1950

*22

90

90

90

V2

1965

+28

120

105

105

V3

₁₈₅₀

+11

100

91

93

1990

+27

120

106

110

V5

2000

70

6

55

V6

1980

0

60

50

50

V7

2000

=21

70

66

67

v8

₁₉₉₀

=16

60

59

Vi

1650

O-11F

70

71

6 V2

₁₆₅₀

=1

90

80

80

V3

1650

i6

80

76

73

1650

=20

60

66

65

V5

1650

=23 50

38

36

V6

₁₆₅₀

30

30

30

29

V7

1650

C-50 1+0 31+

30

V8

₁₆₅₀

61+

30

27

26

Vi

₁₈₅₀

+2

100

91

90

V2

1850

.9

90

91

90

V3

1850

=5

80

86

85

V'+

₁₈₅₀

₌₅

100

88

85

V5

1850

10

50 1+3

35

V6

₁₈₅₀

₂₇

1+0 1+1+ 1+1 V7

1850

70

51 V8

₁₈₅₀

3Lf

₈₀

51+ 58

Vi

2050

=3

110

102

103

V2

2050

+8

90

95

95

V3

2050

+8

100

₉₇

₉₅

Vii-

2050

1

110

101

100

V5

₂₀₅₀

₂₃

90

5'l

59 V6

₂₀₅₀

=18

60

61

55

V7

₂₀₅₀

=22

60

63 61+ V8

₂₀₅₀

₌₃₁

50 53 1+7

-7-TABLE 8 (CONTINUED)

Heat

No0

Rolling

Temp,°F

12 ft-lb Keyhole

Charpy

Transi-tion Temp,°F

Navy Tear Tet Transition. TeDIL, °F

5O 50

Kahn

Brittle Fracture

Brittle Tests

21

1820

-18

60

66

₆₅

'Z2

1810

-10

60

51

57

Z3

1830

-16

70

57

55

1830

-37

50

39

38

25

1980

-1

90

89

90

26

₁₉₅₀

+2

110

96

100

27

1855

+9

90

89

90

z8

₁₈₉₀

0

80

73

75

Zl

₁₆₅₀

_-37

50

6

22

₁₆₅₀

_-31

60

56

62

23

1650

-38

50

39

1650

-53

30

21

19

25

1650

-11+

90

75

76

26

₁₆₅₀

-16

90

87

83 Z7

1650

-2

60

60

62

28

₁₆₅₀

-11f

60

51 51 Z1

₁₈₅₀

_-30

60

₆₃

61

£2

₁₈₅₀

-16

80

71

75

23

1850

-21

70

₅₉

₅₉

1850

=35 60 52

₅₀

1850

-10

90

86

85

26

1850

_-7

₉₀

₈₇

₉₀

Z7

1850

.12

80

70

71

Z8

₁₈₅₀

-io

80

₆₇

6)+

21

₂₀₅₀

-12

100

₉₃

₉₂

22

₂₀₅₀

-

100

88

₈₉

Z3

₂₀₅₀

-

₉₀

₈₂

₈₀

21+

₂₀₅₀

_-17

₉₀

₈₀

83

25

2050

+8

110

108

₁₀₇

Z6

₂₀₅₀

₊₉

₉₀

₉₁

₉₀

Z7

z8

2050

₂₀₅₀

+21

_.18

loo

₈₀

97

₈₃

₈₁

99

it can be mentioned that twenty specimens of each steel were

usually tested0

Before discussing the relationships among the transition

temperatures listed in Table 8, the uncertainties involved in

experimentally determined transition temperatures will be

considered Q

EXPECTED UNCERTAINTY IN TER TEST TRANSITION TEMPERATURES The data on Type A heats in Table '-e- of Part I of this

report can be used for estimating the uncertainty attached to

tear test transition temperatures defined on different bases0

This can be done for the Kahn definition and for p =

probability of brittle fractures at the transition temperature0

Fig0

10 is a plot on probability paper of data obtained

from 130 specimens of Type A steel0 Four specimens were tested at 50°F; groups ranging from 8 to 1e.l specimens were tested at the other temperatures0 The trend line and 9 per cent con fidence limits were determined by probit analysis0 The tem

perature corresponding to a probability of brittle fracture

p = 005 is 73°F0 This is the transition temperature for that criterion0 The 95' per cent confidence limits for this transi tion temperature are 73

52 0F

or

678

and

7802°F,

based on

testing 130 specimens0

If the transition temperature were to be determined by

o 20 40 60 8O

I-

100 120 140 160

-9-99 90 70 50 30 IO

Probability

of

Brittle

Behavior,

per cent

FIGURE IO.

PROBABILITY

OF BRITTLE

BEHAVIOR IN NAVY TEAR TESTS

ON TYPE A STEELS AT VARIOUS

TEMPERATURES

O-22383

95 per cent

limit

confidence Trend

by probit

line determined

analysis

z,,

95per cent confidence

limit

lo

e farther apart0 They would be increased by a factor

or 255

This means that by using the probability of 20

brittle fracture p 0 to define the transition

tempera-ture,

₉₅

determinations out of 100 would lie within a 2605°F

(2q55 x

10+°F) interval0 The expected distribution is illus=

trated by the lower chart in

Fig0 110

Similar deductions can be made about the uncertainty of

the Kahn transition temperature by considering the probabilities

of encountering brittle or ductile specimens when testing groups

of four specimens at five temperatures0 It would not always be necessary to test

20

specimens because the testing temperatures

are chosen according to the sequence in which brittle specimens

are encountered0 The Kahn transition temperature is the high est temperature at which at least one specimen of four

iS

brittle

and 10°F below the temperature at which four specimens are

ductile0 Hence, it can be defined by as few as five specimens0 Since it is usually based on fewer observations the Kahn transi tion temperature would be expected to have wider limits of un= certainty0

Table

₉

lists the probabilities of encountering brittle specimens when testing groups of four samples at various tem= peratures0 They are based on the trend line in

Fig0

10 The

last two columns give the probabilities of encountering four

40

30

20

Kahn - Im be mb o

criteri on

95 per cent confidence

50 60 70

-11-80 90

loo

HO

Transition

Temperature, F

FIGURE II. COMPARISON OF DISPERSION 0F TEAR-TEST TRANSITION

TEMPERATURES BASED ON TESTING 20 SAMPLES

O-22384

Using

brittle

pO.5

probability

of

fracture

for criterion

95

confidence

per cent

-4)

40

3°

20

lo

o 50 60 70 80 90

loo

l'o

TABLE 90 PROBABILITIES CALCULATED ON BASIS OF FIGURE lo FOR PREDICTING BEHAVIOR OF GROUPS OF FOUR TEAR

TEST SPECIMENS OF TYPE A STEEL TESTED AT VARIOUS

TEMPERATURE S Testing Temp, °F Probabilitie s First Specimen Brittle Second Specimen Brittle Third Specimen Brittle Fourth Specimen Brittle All Four Ductile At Least 1 of -Brittle

60

_O76

ol82+

00+38

_0OlO5

0O033

09967

70

055

075

0O9O9

0O95

o0o+o8

_O959

80

_O35

₀₂₂₇₅

0l+78

O09+1

01785

o82I5'

90

Ol9

001

53 9

012+6

Ol01O

O,+3O3

O%97

loo

oo8

o 0736

oo677

oo623

O716+

02836

13

in, a group of four0 From these values, the Kahn transition

temperatures to be expected when testing Type A steel can

be deduced0 If testing is started at 600F, for example, the

probability of

setting the Kahn

transition

temperature at 800F

depends on the probability of finding at least one brittle

specimen out of four at 80°F or lower temperatures and on the

probability of testing four ductile specimens at 90°F0 Accord

Ing to Table

_9,

the probability of the Kahn transition tempera-ture being 80°F is:

0997 x 0959 z o82l5 x 0+3

o338

Similar calculations for the other temperatures lead to the

upper chart shown I

Fig0

11 This chart. shows that the ₉₅

per cent confidence limits for the Kahn

transition

tempera ture covers a range of i-+°F0 It Is a wider range than that for the

lower

chart because It depends on

Information

provided

by eight specimens or less

even when more are tested0

The frequency charts in

Fig0

li show that when 20 speci mens are available the transition temperature can be determined

more precisely

using

the probability criterion0 The charts

indicate that the Kahn criterion is less desirable for

research

purposes because it leads to wider uncertainty limits0

Perhaps It should be mentioned that the data in Table 9

suggest that the Kahn transition temperature may he Influenced

starting tests at low

temperatures leads to lower values of

the Kahn transition temperature0 This can be illustrated by

calculations from the data in Table 90 If tests are started at 600 or 70°F, the probabilities are

O338

and O321 that

the Kahn

transition

tempe'atures would be 3QQ and 900F, re= speetively0 When starting tests at 110°F, the probability

is 022+ that 800F and 0362 that 90°F would be chosen by the

Kahn criterion0 Biasing the Kahn transition temperature

toward the direction from which

it is approached occurs because

of the way in which it is defined0

CORBELATION ANALYSIS OF TEAR TEST DATA

The relationships among the transition

temperatures listed in Table 2 were examined by standard methods of

statistical

analysis0 The results of the correlation analyses are .sum

marized in Table l0

It is apparent that transition temperatures, defineJ. on the basis of probability of brittle fracture p

05 and on

the basis of 50 per cent brittle texture9 are in

closest

agreement0

Fig0

12 illustrates this correlation0 The slope

of the trend line is l01+ arid the correlation coefficient

is O986

The scatter from the trend line is small, and the standard error

iS

only 30700F0

These data show that transi tion temperatures defined on the basis of 50

per cent brtt1e

C o LI, _C) 1L 120 loO

- 60

C 4)

o

o

LI) 40 20

-15-/

/J/

/y7;

Low carbon High carbon heats O heats (_l

,

0.

Or,

/

B..

..

/

.,

/

o,

/

_./

_/

P

/.

0/

/

/

/

/

/

.S/

,

/

0

.- co

" 0

/

.,

..

_/

/

e.,

'

/

-/

/

,

o 20 40 60 80 lOO 120 Transition Temperature, F

(50 Per Cent Brittle Tests)

Fl GURE 12. COMPA RISON OF TEAR-TEST TRANSITI ON - TEMPERATURE CRITER IA

TABLE

loo

CORRELATION BETWEEN TRANSITION TEMPERATURES

ESTABLISHED BY DIFFERENT CRITERIA IN TESTE

ON

95 MATERIALSO FOUR SPECIMENS WERE TESTED AT

EACH TEMPERATURE OF INTERESTO

X2

X3

t t rbu t e s

=160=

Attribu

X1 12

f t1b keyhole Charpy transition temperature

Kahns definition, tear test transition temperature

50 per cent brittle fracture texture, tear test transitIon temperature

O5 probability of brIttle fracture, tear test

transition temperature

Regression EQuaiofl

Qf.ii&

X1) X2 Xl, X3 Xl, X+ X2, X3

X3X

X2 o08o10 xl +

₈₇₃₆

X3

O855 X1

+

8i6i

Xi

O85 X1

+

813

X3 = O8859

X2 +

l95

X

_O939

X2

i85

= 1O])+ X3

ii8

1l temperatures în degrees Fahrenheit

Standard Correlation Error of stimate, O 723

1531b F

O791

13007°F

0769

1403°

F O 919

80F

O 9+3

7032°F

o 986 3070° F

l7

p = 05 for brittle specimens0 In either case, data obtained

from all specimens tested contribute to establishing the transi-O tion temperature0 As explained in the previous section, this

establishes transition temperatures with smaller limits of

uncertainty

The correlation between the Kahn transition temperature

and the temperature at which the fracture surfaces average

5O per cent brittle texture is shown in Fig0

_l3

There is considerably more scatter from the trend line than in Fig0 l2

Table 10 shows that the correlation coefficient is lower and

the standard error is higher, 80+°F Much of the scatter

from the trend line in

Fig0

13 is attributed to the wide un

certainty limits for the Kahn transitIon temperature0 Four points all on the high side, fall outside the two sigma limits

on the chart0 This behavior suggests that the Kahn criterion occasionally sets the transition temperature too high0 It

appears that erroneous ratings by this criterion are more

likely to be on the conservative side0

CORRELATION OF OHARPY AND TEAR TEST TRANSITION TEMPERATURES

Both Charpy and tear tests are used to evaluate the

susceptibility of steels to brittle fractures0 Since both tests employ notches and are used for the saine purpose, it is

natural to seek factors useful for estimating transition tem

peratures for one type of test from data obtained by the

120 100 tL Q) 80 E D 40 20

-i8-/

/

/

/

/

/

/

/

Low carbon heats

O

High carbon heats

/'

O

/

/

O

.'

/

/

/

₎₍

/

/

/

..sc.»./

/

/

/

/

/

Q,"

/

cfo D...

/

S((

/

/

..

/

/ ..

O

o

2o-O

/

/

/

/

/

/

_/

/

/

/

/

/

o 20 40 60 80 lOO 120

Transition Tern pera ture, F

(50 Per Cent Brittle

Fracture

FIGURE 13. COMPARISON 0F TEARTEST TRANSITIONTEMPERATURE CRITERIA 0

223 86

i 9

other procedure0 Therefore, the correlation betwen keyhole

Charpy and tear test transition temperatures determined for

these 95' steels was examined0

Fig0

l+ and 15' show considerable scatter occurs 'when

tear test transition temperatures are plotted against Charpy

transition temperatures0 Table 10 shows that the standard

errors of estimate range around 1+°F and the correlation

coefficients around O76 The regression equations indicate

that the difference in Charpy and tear test transition tem

peratures is larger for steels with the lower transition

temperatures. Defining the tear test transition temperature

by Kahns criterion gives the poorest correlation with Charpy

transition temperatures. However, using the other two criteria

for defining tear test transition temperatures does not

sij-icantly improve the correlation with Charpy results.

The correlation analyses indicate that one-third of the

estimates of Charpy transition temperatures from tear test data are likely to be in error by 13°F or more0 Data for

these steels illustrate the danger of serious errors in

estimated transition temperatures based on data obtained in

other types of tests0 These data suggest that Charpy and tear tests do not measure the same type of' transitions.

o 40 20 o > o ₂₀

u

a) o >' a) -40 -o 9-('J 60

-20-/

/

Charpy versus Kahn transitions

Low carbon heats O

High carbon heats S

/.

/

/

/

.

5

/

___/

/

S

/

.

1..

.

.

/

/

/

I.

0.

o

0.

0

.

s

o

/

.8/

_/

/

O'

'O

0/

/

o

/

o

/

2

8

/

/

0 20 40 60 80 lOO 20

Tear TestTransition

Temperature, F

Kahn

Criterion)

FIGURE 14. POOR CORRELATION BETWEEN TRANSITION TEMPERATURES

ESTAB-LISHED

BY CHARPY AND TEAR TESTS USING THE

40 C o C o t-> Q. 20

o

0 o

r-40

M-20 cJ

-

60 _oi -80o _{20 40} 60 80 lOO 120

/

/

/

/

/

/

Chorpy versus

brittle

fracture

Low carbon High carbon 50 per heats heats cent

0

/

/

2e

/

/

e

t

/

o

/

/

¡s

/

.

c5

5/

/

/

/

0/0

,5

/

0,

O

/

.

_aDoec!

O

c.

o.

O?

e

0/

/

/0

/

Ip

/

.

oo

o

00,. 0

0,00

/

/

/

/

/

/

/

o

00

0

/

0/

2'

/

/

0,

0

/

/

Tear Test

Transition Temperature, F

(50 Per Cent Brittle Fracture)

FIGURE 15. POOR CORRELATION BETWEEN CHARPY TRANSITION TEMPERATURES

AND THAT SET BY TEAR TESTS USING THE 50 PER CENT

BRITTLE TEXTURE CRITERION

REFERENCES

ll3 At end of Part I of this report

l+ Frazier,

R0 IL, Boulger, F0 W0,

and Long,

C0 H0 'Influence of Silicon and Aluminum on the Prop

erties of HotRolled Stee1, Sixth Progress Re

port, Ship Structure Coimnittee Report, Serial