The fundamental factors influencing the behiavour of welded structures under conditions of multiaxial stress and variations of, temperature

OCTOBER 14, 1952 SERIAL NO. SSC-54

oO9

LAtOATORU'l VO'DR

r r' ç ç" P s -

-THIRD PROGRESS REPORT (Project SR-99) On

THE FUNDAMENTAL FACTORS INFLUENCING THE BEHAVIOR

OF WELDED STRUCTURES UNDER CONDITIONS OF MULTIAXIAL

STRESS AND VARIATIONS OF TEMPERATURE

by

E. B. Evans end L. .J. Klingler CASE INSTITUTE OF TECHNOLOGY

Under Bureau of Ships Contract NObs-45470

(Index No. NS-01 1-067)

Transmitted through

NATIONAL RESEARCH COUNCIL'S COMMITTEE ON SHIP STEEL

Advisory to

SHIP STRUCTURE COMMITTEE

under

Bureau 0f Ships, Navy Department Contract NObs-501 48 (Index No. NS.731-036)

LAE.ORATORIUM VOOR

SCHEEP.CONSTRUCTES

Dvhion of Engineering and Industrial Research National Academy of Sciences . National Research Council

Dear Sir:

Attached is Report Serial No. SSC-5+ entitled

'1The Fundamental Factors Influencing the Behavior of

Welded Structures Under Conditions of Multiaxial Stress

and Variations of Temperature" by Evans and Klingler.

This report has been submitted by the contractor as a

Third Piogress Report on Contract NObs-+51i-7O, Index No.

NS-011-067, between the Bureau of Ships, Department of

the Navy and the Case Institute of Technology.

The report has been reviewed and acceptance

rec-ommended by representatives of the Committee on Ship

Steel, Division of Engineering and Industrial Research,

NRC, in accordance with the

terms

of the contract between

the Bureau of Ships, Department of the Navy and the Na-tional Academy of Sciences (Contract NObs-5O18, Index

No. NS-731-036).

Very truly yours,

NATIONAL RESEARCH COUNCIL

2101 CONSTITUTION AVENUE.WASHINGTON 25, D. C.

COMMITTEE ON SHIP STEEL

OF TRE

DIVISION OF ENGINEERING AND INDUSTRIAL RESEARCE

October 31, 192

P. E. Kyle,

ChaIrman

Committee on

Ship

Steel

Advisory to the SHIP STRUCTURE COMMITTEE, a committee representing the combined research activities of the member agencie8

-Bureau of Ship8, Dept. of Navy; Military Sea Transportation Service, Dept. of Navy; United States Coast Guard, Treasury Dept.; Maritime Administration, Dept. of Commerce, American Bureau of Shipping.

THIRD PROGRESS REPORT

on

The

Fundamental Factors

Influencing the

Behavior of Welded Structures under Conditions of Multiaxial Stress and Variations of Temperature

to

SHIP STRUCTURE CON}'IITTEE via

Bureau of Ships

Department of the Navy

Contract NObs5+7O

Index Noi, NS-011O78

Project SR-99

by

E0 B. Evans and L0 J. Klingler

TABLE OF CONTENTS Page T able of Contents . , 0

i

Abstract 0 o o o o o o o e o o o o o o o o o o o o o jj Introduction i Material

000 ...

00000000 00000

Procedure

Welding Technique

oo0on0o0O000oo0O0O

Test Specimens ... ....

Specimen Preparation . ..

Testing Procedure ... Results

Eccentric Notch Tests at the

Surface Level .. ...

Eccentric Notch Tests at

Selected Locations in the

Weld Metal . , ComparisonTests0 ...

Discussion00000000

... Conclusions . . . 0 Future Work .

00000000..

Acknowledgments ... B ib1iograpiy Figure s Appendix 6 8 10 12 19 21 27 32 3 2

3+

35

ABSTRACT

The eccentric notch

tensile

test previously employed

in exploring the relative ductility at the midthickness

*

level of A and C steel weidments has been applied to an evaluation of the ductility at the surface level and at various positions in the weld metal of a C steel weldment

The surface tests at various low temperatures located a zone of low ductility at a distance of 0)+ inch from the

weld centerline of

3/+ inch plate0

This zone was outside

the so-called heat affected zone and appeared to have the

same metallographic structure as the base platee These

findings

are in agreement with those previously reported at the midthickness level of both A and C steel weldments0

Low temperature probe tests

in

the weld metal failed to

detect any zones of

low ductility0

In addition, data are presented comparing the notched (eccentric and concentric) and unnotched tensile proper ties at the midthickness level of an A steel weldment0 Various low temperature tests revealed that the concentric

notch ductility varied across the welded plate in the same

manner as the eccentric notch strength thus confirming that the eccentric notch strength is a measure of notch

ductility0

in contrast, the variation in concentric notch strength and unnotched tensile properties across the welded

*The designations A

steels

AU and j-j

the series of Ship Structure Cowiiittee _{Project' teels0}

plate failed to detect zones of low ductility in the sub-critically heated plate.

A comparison with other investigations of welded plate indicates that the eccentric notch tensile test is not unique In defining a region of minimum ductility in the subcrItically heated parent plate and that this region may play an important role in the fracture be-havior of welded plate0

THIRD PROGRESS REPORT

on

The Fundamental Factors Influencing the

Behavior of Welded Structures under Conditions

of Multiaxial Stress, and. Variations of

Temperature, Stress Conentratior

and Rates of Strain

to

SHIP STRUCTURE COMMITTEE

via

Bureau of Ships

Department of the Navy

by

E0 B0 Evans and L0 L Klingler

INTRODUCTION

This report summarizes the work completed

on commercial

ship plate weidments on a project sponsored by the Ship

Struc

ture Committee under U0 S

Navy contract NObsJf5+7O and covers

the period from July 19

l9+9

to January 19 195O

Technical

Progress Reports SSC-2

(1)*

and SSC3+ (2) covered

the prc

gress of the investigation to July 19 l99

The previous work was :cojcerned with establishing the

existence of zones of low ductility in welded ship plate9

and

the dependence of these

_{zones upon materIal9 variations in}

the welding process, and heat treatment0

_{The ductility}

through-out the weidments was evaluated by means of eccentric notch

tensile tests conducted at various low temperatures9 using the

notch strength as the

criterion0

Numbers in parentheses refer to the bibliography at the

end of the report0

2

The two previous reports contained the test results

of specimens taken from the niidth.tckness level of 3/+.-1nch

plate of A and C steels, two of the project steels which

had been investigated by other groups0 A brief sunmiary of

this work is presented below0

Eccentric notch tensile tests of as-received plate established a transition temperature of =80°F for A steel

and 65'OF for C steel0 After welding using a 100°F pre heat and interpass temperature, a zone of minimum ductility

was located at a distance of 03-0 inch from the weld

centerline of both the A and C steel weldments0 The

transition temperature of this critical zone wa J+0°F for

A steel and =20°F for C steel9 thus indicating an appreciable

enthrittlement in both steels0 The transition temperature of

the weld metal was not determined but it was definitely lower

than that of the parent plate0

In order to investigate the possible beneficial effects of preheating and postheating, weidments of C steel were

made using (1) a 000F preheat and interpass temperature9

and (2) a postheat treatment at 1100°F to a weldxnent which

had been welded with a 100°F preheat0 The +0O0F preheat

improved the ductility in the critical zone9 lowering the

transition temperature to

+°F0

The 1100°F postheat

completely eliminated the zone of minimum ductility9 the

Temperature measurements during welding and the

microstructure of the critical zone showed that this

region was not heated above the lower critical

temper-ature at any time and9 therefore the critical region

was outside the socalled heat affected zone0 Con

sequently, the embrïttlement (are the improvement brought about by preheat arid postheat treatments) was thought to be due to some subcritical temperature phenomena

which may be the supersaturation and precipitation of

carbides and/or nitrides from the alpha phase0

In view of the fact that the previous werk was

confined to tests at the plate midthickness, it was considered advisable to continue the investigation at the surface level to determine any difference due to

gross inhomogeneity of the plate0 This study was limited

to a C steel weidment made with a 100°F preheat and

interpass temperatur0 The same weidment also supplied

specimens for an evaluation of the ductility at selected locations in the weld metal0

This report also presents data comparing the notched

(eccentric and concentric) and unnotched tensile proper-ties at the mid-thickness level of an A steel weldment0

This phase of the

investigation

_{was carried out at low}

centerline with two objectives in view:

L To confirm that the eccentric notch tensile

strength is a measure of the notch ductility of ship plate steel.

2. To determine if the unnotched tensile test

can be made sufficiently severe, by the use of low temperatures to detect ductility variations in ship plate steel.

The findings of this investigation are discussed with

those of other Investigations of welded plate with particular

reference to the origin of fracture.

MLTERIAL

The A and C ship plate steels selected for the present

investigation were the same two "project steels" which had been used in the earlier work at this laboratory. Both were semi..killed steels in the as-rolled condition. The properties reported for these steels are as follows: (3)

5-TABLE I

Properties of A and C Steel Plate Chemical Analysis

Carbon Manganese

Phosphorous Sulfur Silicon

C Steel 0.21+ o,-i-8 0.012 _{0.026 0.05}

A Steel 0.26 0.50 0.012 _{0.039 0.03}

Aluminum Nickel Copper Chromium Molybdenum

C Steel 0.016 0.02 _{0.03 0,03}

₀₀₀₅

A Steel 0.012 0.02 0.03

003

0006

Tin Nitrogen Vanadium Arsenic

C Steel 0.003 0.009

0.02

0001

A Steel 0.003 0.00+

002

001

Mechanica1 Properties

Yield Point Tensile Strength Elongation

Psi Psi _{Per Cent}

C Steel _39,000

PROCEDURE

Welding Procedure

The plates were at Batteile Memorial Institutes following the same closely controlled procedure used

previously l)(2)Q Details of the plate preparation

and welding procedure are given in Figs i and 2

Each weidment was 18 x 2+' x 3/+ constructed

of two plates 9 x 2 x 3/L _{in dimensions*0 These}

plate s were flame cut from the same large plate and

3A-inch was machined from the edges to be welded in

order to eliminate the heat effect of the flame cuttings The

edges to

be welded were

then

machined to a 300

bevel and l/8-4nch root face0

The plates were tack welded using one-inch tacks

at each

end

and at the center of the plate, leaving

3/16-inch clearance between the root faces0 À copper

back-up bar coated with a thin layer of wollastonite was used for the first weld pass0

No restraint other than the tack welds was used on the weidments and because two inches from eath end of the plate wer, to be discarded9 no runnoff tabs were

required0 The welding was manual; six passes were made

using 3,'16-inch diameter E6010 electrodes wIth DC

re-verse polarity0 The

weldIng data

are given in Table IL

* _{The 2} ? dimension _{was the rolling direction of the}

-7-600

EDGES MACHINEBEVELED

FIG.I:

PLATE PREPARATiON

)

ELECTRODE - 3/16 E6010

PASSES

I,3

5)6v: SAME DIRECTION

PASSES

_{2b4: OPPOSITE DIRECTION}

TABLE II Welding Data Harnischfeger

D0 C0

Welder Electrode:

3/16" E6010

Current 150 amps 165 amps Voltage 25 volts

Welding Speed

36

in/min in/min

Electrode Burn=Off

85

in/min

Rat e Reversed Polarity Pass i Passes 2 6 Passes 1 6 Pass i Passes 2 6 Passes 1 6

The weidments were preheated to 1000F prior to

the first weld passe After each pass the weld joint

was cooled in still air to 100°F and then the next

pass was made0

After completion of we1ding, the welded joint was

sand blasted and then radiographed for weld imperfections0 Test Specimens

The three types of tension specimens obtained from the weldments are shown in

Fig0

The two notched test specimens had 60° V-notches

removing 50 per cent of the cross sectional area and

a root radius less than 000l inch0 The buttonhead

notch specimen was employed in the concentric tests

and the threaded md notch specimen in the eccentric

A 7/16-20 THDS 1/2 /2"

1/2"

-

-9-60° ¡Ç r

/

R000I"

\ /

k 0.300" -4-- 3/ 6"- p-4- 3/ 8

-6--I-1/2'

_-1/16

ECCENTRIC NOTCH TENSILE SPECIMEN

0040"R/

,v

0.2(2

40

I-1/2 _1/16'

CONCENTRIC NOTCH TENSILE SPECIMEN

-4.0

l-1/2 _-1/16"

UNNOTCHED

TENSILE

SPECIMEN

FIG. 3: TEST SPECIMENS

LINE OF

TENSION FORCE

/4 ECCENTRICITY

The unnotched test specimen had a two-Inch radius9

with the same minimum diameter (O2l2 Inch) as the notch

diameter of the notched specImens Specimen Preparation

All of the test specimens were obtained from strips,

l/2inch wide, which were cut from the welded plates per

pendicular* to the weld0 Each strip was etched so that

the weld area was visible arid the weld centerline could

be located0 The specimen locations for each type of

test specimen were then laid out as follows:

Eccentric Notch Tensile The notch bottom was

positioned at the desired distance from the weld center

line and so that the fiber carrying the highest tension load was at the desired distance from the plate reference

surface0 For the surface investigation, the fiber

carry-Ing the highest tension load was OO5 inch from the sur-j

face0 This close approach to the surface resulted in

specimens witha flat on the threaded ends9 as shown in A number of specimens were also prepared so that the critical fiber was at the mldthickness of the plate

(longitudinal axis O+8 Inch from the reference surface),

and at selected locations in the weld metal0

Concentric Notch Tensile The notch bottom was

at the desired distance from the weld centerline with the

long axis of the specimen O+8 inch from the surface0

* _{The long axis of each test specimen was, therefore9}

perpendicular to the rolling direction of the base

o CENTERLINE OF SPEC IM E NS HEAT AFFECTED ZONE

-11-REFERENCE SURFACE

U:11

o

i

II JI

FIG. 4

LOCATION OF ECCENTRIC NOTCH

SPECIMEN AT THE SURFACE LEVEL

REFERENCE SURFACE

CENTERLINE OF PLATE AND FIBER IN MAXIMUM

TENSION ON ECCENTRIC

L OAD) N G

FIG. 5

_{LOCATION OF UNNOTCHED AND NOTCHED SPECIMENS}

AT THE MIDTHICKNESS OF WELDMENT

12

Cc) TJnnotched Tensile The minimum diameter was

at the desiréd distance from the weld centerline with the long axis of the specimen O8 inch from the sur

face

The location of these specimens at the mid

thick-ness level (away from the weld) is shown in

Fig0

Testing Procedure

The test equipment and procedure for the eccentric notch tensile tests were the same as those used previously

(1) (2)

The specimens were placed in the fixtures,

Fig0

69

so that the critical fiber received the maximum tensile

stress0 The initial eccentricity was set at l/ inch,

that is, the centerline of the specimen was displaced i/+ inch from the loading axis of the tensile machine as shown in Figo 6

The specimen was cooled to about 5'°F below the de sired testing temperature, allowed to warm up to the

test-Ing temperature and then tested. The tests were per

formed at constant temperature since the testing time

was about 30 seconds, whereas, the warming-up rate was

about 1°F per minute0 The specimens were cooled by means

of isopentane, dry ice, and. liquid nitrogen contained in

an insulated tank0 Temperatures were measured by a copper

-13-JAf1'Z MlA

'4A' JA'

/NAf

YAf,4'cfJû,41 jYcf/OìV

cJAC/NA'

û/_ 2c2,142/,4'C 79 ¿'6'Yl/,+'

-cf4'r,9/c/Tr (cc ,7f/C/7

,4A'9 7,V,

of the tests were carried out at a low strain rate; the

crosshead speed of the tensile machine was approximately

001 inch per minute0

The testing procedure for the concentric notch and

urinotched tensile tests was generally the same as described

above with the exception that the specimens were tested in

a fixture

designed to yield an eccentricity of

less than 0001 inch (+),

The crosshead speed of the

tensile machine in these tests was approximately 0o0

inch per minute0

For the eccentric and concentric notch speciniens

the conventional notch strength was determined (maximum

load divided by the original area at the notch bottom)0

Also, for the concentric notch specimens the contraction

in area at the root of the notch or 'notch ductility'

was obtained by measuring the initial and final notch

diameters by means of a microcomparator (at 20x).0

The conventional tensile strength and reduction

in area were calculated for the unnotched tensile specimens.

RESULT S

Eccentric Notch Tests at the Plate Surface

The results obtained from the tests at the plate sur

face of a

steel weldment made with a i00F preheat

and interpass temperature are graphically presented in

Figs0 8 and 90

For purposes of comparison the previous

-15-Fig. 7: - CONCENTRIC FIXTURE SHOWING

UNNOTCHED TENSILE SPECIMEN

IN POSITION FOR LOW TEMPERATURE TESTING.

200 160 00

I

L)

I-o

Z ₈₀ 40 o

- 40

-16--lOO

-60

-20

-t-20 1-60 -t-00 TESTING TEMPERATURE-°F I

FIG. a:

ECCENTRIC 1NOTCH STRENGTH OF THE UNAFFECTED

BASE PLATE AS A FUNCTION OF TESTING

TEM-PERATURE.

o TESTS TESTS 0.05 AT I STEEL GEOMETRY "G'1 BASE FROM PLATE MIDTHICKNESS AS AT I PLATE SURFACE (SPECIMENS TP-lE SURFACE) OF SAME 6 o DISTRIBUTION RESULTS AT 0F PREVIOUS THE AIDTHICKNE5S

200 60 20

I

o 80 o 40 o o

-17-0.5 1.0 LS 2.0 2.5

DISTANCE FROM WELD CENTERLINE INCHES

FIG. 9:

DISTRIBUTION OF ECCENTRIC NOTCH STRENGTH

AT 80° F

3.0 TESTS WELDMENT C STEEL 005 INCH FROM - 000 F PREHEAT PASS TEMPERATURE PLATE AND INTER-SURFACE PREVIOUS RANGE 0F VALUES AT THE A FOR 2 RESULTS MIDIHICKNESS. b o o e

**

for the surface tests appear ïn Table I of the Appendix0

In Fig0 8 the eccentric notch strength values for

the unaffected base plate * are shown as a function of

testing temperature All of the surfae results fall

in the lower two-thLrds of the rnidthickness distribu-. tion, indicating that the high values have been lowered.

Consequently, the transition temperature** at the sur

face (-.60°F) is slightly higher than at the midthickness

(-.65°F)

In order to check the possibility that the specimen geometry was the cause of the lowered values, a number

of specimens from the midthickness of the plate, but with

the same geometry as at the surfaee were tested at 1l0°F

and room temperature. Slightly higher results (plotted

as filled circles in Fig,

8)

were obtained indicating

that the lower values obtained at the surface were not the result jf specimen geometry but probably due to

slight decarburizatlon0

In Fig. 9, the distribution of eccentric notch strength at various distances frofl the weld center

line Is shown for a testing temperature of

8O°F.

The

surface tests show the same general behavior as the

Unaffected base plate specimens were taken at a

distance of two inches or more from the weld center-line and thus were unaffected by the ielding9 since

the maximum temperature reached

in this zone

was

less than 6000F0

Transition temperature is here defined as the tem perature at the mid-point of the average notch

midthickness tests, 10e09 a minimum at a location outside

the weld area0 The minimum at the surface level (0)i- inch

from the weld centerline) was shifted approximately 0l

inch further from the centerline but this is due to the

geometry of the doubleV

weld0

The microstructure at the

minimum was the same as that found previously at the mid thickness minimum, and no change in structure was noted between the critical zone and the unaffected base plate0

The same behavior would be expected for the 'A' steel

at the surface level, based on the similar behavior of A and C steel at the midthickness (2)

Eccentric Notch Tests at Selected Locations in the Weld Metal

In order to investigate the possibiity of zones _of

low ductility in the weld structure, a number of probe

tests were conducted at -80°F at selected locations in

the weld metal of the same steel weldment0 The re

suits are given below in Table III and the positions under test are shown in Fig0 lO

TABLE III

Eccentric

Tests in "Co rse Structure" Weld Metal Notch Strength,

Qi

Position in Weld Metal

A0 The coarse structure at the junction

of the hardness peak from pass ₅

B0 The Coarse structure at the weld

centerline, approximately 003 inch from the plate surface

C0 The coarse structure of pass 2 at

the weld centerline

l2l3

i21)+

ll29

ll28

113.3

l213

l236

-20-FIg. 10:- TESTS AT SELECT

LOCATIONS IN WELD

At all these positions (and also at the midthickriess

and surface levels) only high eccentric notch strength

values were obtained which would seem to preclude the

existence of zones of low ductility in the weld metal0 Comparison Tests

The use of the eccentric notch tensile test to de tect changes in ductilIty throughout ship plate weidments

was based on the results of previous investIgations (1+)

(5)

which showed that the eccentric notch strength was dependent upon the concentric notch ductIlity for heat

treated low alloy steel at various strength levels0 To

confirm this dependency for ship plate steel9 concentric and eccentric notch tensile tests at various low tempera tures were made at the midthickness level of an A steel

weldment (100°F preheat and interpass temperature)0 Un

notched tensile tests were also made on the sanie weldment

to determine whether this test could be made sufficiently

severe by the use of very low

temperatures, to

detect

ductility variations in ship plate steel0

The data are given in Tables II IV in the Appendix0

Unaffected Base Plate In O1I the distribution of

the concentric notch strength and concentric notch duc

tility of unaffected base plate is shown as a function

of the testing temperature0 For comparison purposes the

results of the eccentric notch tests

previously

_reported

I

o

I.-o

_Z

z20

ww

>- LU ₅ HUJ

o

IO Z

I

o

5

HZ

20 80 40 o o 120 80 40

-22-ECCENTRIC (PREVIOUSLY TESTS REPORTED)

°:

/8

oo7

1/Y,,

° CONCENTRIC TESTS o

cF

CONCENTRIC TESTS -8 o0

::

o

-340

-260

-ISO

-lOO

-20

60 140 TESTING TEMPERATURE°F

FIG.

ii:

COMPARISON OF THE ECCENTRIC AND CONCENTRIC

NOTCH PROPERTIES AS A

FUNCTION OF TESTING

TEMPERATURE. MIDTH(CKNESS TESTS OF

tA" STEEL

23

It can be seen in

Fig0

11 that the eccentric notch

results define a relatively narrow temperature range in which the strength values decrease rapidly with decreas

ing temperature The concentric notch strength values,

however9 are relatively constant over this saine temper=

ature range, and only at 32l0F Is there adecrease in

notch strength0 Thus, the ductilebrittle type of be

havior or transition curve Is not defined by the COflc

centric notch strength9 at least down to 32l°F. On

the other hand, the concentric notch ductility (per cent reduction in area at the root of the notch).decreases continuously with decreasing temperatures but with no

definite upper level as in the eccentric notch strength

distribution0

r

A closer examination of these curves shows that the

concentric notch strength appears to be dependent upon

the ductility at low values0 Specimens strained over

say two per cent9 haVe lost their high initial stress

concentration, which was one of the embrittling factors,

and consequently the concentric notch strength Is In

dependent of the ductility0 The eccentric notch test9

however, extends the dependence of the notch strength

upon ductility up to approximately 12 per cent by the addition of another embrittling factors eccentric load

in 1l2 the unotchad tensile properties

tensile

strength and per cent reduction in area) of unaffected

base plate are plotted as

a finct1on of testing temperature.

The tensile strength increases slowly and continuously

with

decreasing temperature over the range from room

temperature

down to liquid nitrogen (32l°F) however the ductility

decreases slowly down to about _l5O°F9

at which point the

ductility drops off rapidly to about one per cent at 32l0F0

These

results indicate

_{that. for the unaffected base plate}

the test is not sufficiently severe to define a ductile brittle type of behavior with the tensile strength as a

criterion0 The per cent reduction In area dos define

this type of

behaviour but only at very low temperatures0

As.Welded Plat The distribution of the concentic

notch properties at various distances from the weld

cen-terline

at

testing temperatures f OcF and llO0F are

shown in

For comparI 5Cfl

purposes the eccentric

notch propertIes at _700F*

and at

liO0F

are also shown0

The concentric notch ductility shows p the regIon of

low ductiity (O3O+ inch from the weld centeriin

ifl the earns manner

as the eccentric notch strength In

spite of the relatively large portion of metal unde

test0 In both cases the minimum became more pronou.ced

as the testing tempeiatur wa lowered0 In contrast

the concentric notch strength distributiond iot define

a zone of minimum ductility9 even at a testing temperature of -llO°F

160 140 120 loo 80 SC 30

z

o H 20 Ö Ui Io o -340

-25-TESTING TEMPERATURECF

FIG. 12:

REGULAR TENSILE PROPERTIES OF

'A" STEEL

AS A FUNCTION OF TESTING TEMPERATURE.

-A 000 F ATURE I STEEL WELDMENT PREHEAT AND MIOTHICKNESS I NTERPASS TESTS. TEMPER-00 _o

X..:

e 0 UNAFFECTED X 0.0 INCH 0 0.35 INCH BASE PLATE FROM WELD FROM WELD CENTERLINE CENTERLINE

-o X___ _____________________________ 8 40 20 o 70 60

5°

40 uJ

J

(J-)

z

LU -180 -100 -260

-20

60 140

I

0

e-o

z

20 80 40 20 >-i.- 15 -J

oz

DW

00

u

QQ-e-- 5

o

z

0

I

F-o

z

uJ

o

Io

0- e-80

-26-o ECCENTRIC TESTS

0 70°F

110°F

o o r o _o o o o I o o e o o o o e CONCENTRIC TESTS

0-40°F

I!0° F

H

CONCENTRIC

o 40°F

TESTS

ltO°F

1

° o 0 0.5 .0 1.5

20

2.5

DISTANCE FROM WELD CENTERLINE INCHES

FIG. 3:

DISTRIBUTION OF CONCENTRIC AND ECCENTRIC

NOTCH PROPERTIES .AT VARIOUS LOW

TEMPER-ATURES-MIDIHICKNESS TESTS OF 'A" STEEL

WELDMENTS, (100°F PREHEAT AND INTERPASS

Th unnotched tensile properties at =llO (average

of duplicate tests) at OO and O3 inch from the weld

centerline are shown in Fig 12 superimposed on the

results of the unaffected base plate0 Both the tensile

strength and the per cent reduction

in area at these

positions are about the same as that for the

unaffected

base plate0 From this limited data it would appear that

the unnotched tensile test is not severe enough to de tect ductility variations in welded platte

DISCUSSION

The occurrence of the region of highest transition

temperature outside the socalled heat affected zone in

weldments has been observed by other investigators0

Grossman

and

Shepler (6) using a notched slow bend

test on weidments of 1 inch thick A212 plate found a peak in transition temperature at distances of 1/2 to 1 1/2

inches from the

weld centerlineq or about l/ or

3/

inch

from the edge of the weld0 Twelve different welding

technïques were used with E6OlO E6020 and HTS Union

melt

electrodes,

A later report by Grossman and MacGregor

(7)

in which

seven

low

carbon steels were tested with unionmelt joints

showed that the transition temperatures determined by the

2 &.

lw bend test passed through a iaximuri outsid th

heat affected zone in all cases except for ozie sem1

killed steel whIch was brttie In th

heat affectd

Nippes and Savage (8) reproduced In Charpy specIr'

men blanks the exact heating and cooling cycle which oc

.curred during welding at various d tar..ces from the 'eLd

centerline th arc welds of 1/2 inch aiumin killed

steel pate0 The results of th impact

tests

showed that

the highest transition temperatum was iocated In a reglen

which was heated to a maximtm temperature of only

_95O)F

during the heating and cooling cyc1e

These investigation which were eonducd on a nm

ber of different weldIng technIques and different test

methods show that the results with th eccentric notch

test; on the A and C steels are not uniue

L mbe

of investigations 9XlO)l1) have been made

using beadcrp1ate notched so bend tests

Variations

of this test. have differed in the specirnerdimensioe

and the depth and shape of th, notch

Th

most work ha

been done using the socai1ed 1inz1 and Leh1gh

spcI

mens In both of these specimens th notch root surface

Transition curves from these tests show an increase in

transition temperature over those found for the same

specimens without the weld bead Higher heat input

preheat, and postheat have all been shown to reduce the embrittling effect caused by the laying of the weld bead. Studies of the origin and progress of the cracks lead ing to fracture have shown that the cracks usually origi-nate either in the weld metal or in the coarse grained

structure adjacent to the' weld deposit at bend angles of only a few degrees, regardless of the test

tempera-ture0 It has not been determined whether these first indications of faiJure are of a ductile or brittle type.

In one investigation (l2) the notch in a Lehigh

specimen was cut so as to eliminate the coarse grained structure, but the first cracking was found to occur in

the structure heated above the critical at the same bend

angle as when it started previously in the coarse grained structure, and the transition temperatures were the saine for the two types of notch0

In a paper by Fountain and Stout (13) tests were

made in which the notch depth was varied so that the

structure at the notch bottom under the weld bead varied from weld metal - coarse grained structure - structure

between 900 12000F (below the critical)0 Transitioei

curves were made only for the standard notch (which ex=

poses weld metal) and the notch located in the region

heated above the critical0 _{In addition9 two specimens}

which were notched In the subcritical _{region were tested} at 0°FO _{These data along with the two transition curves}

are shown in

_Fig0

l The curve for the notch in the region heated above the critical appears to have a lower transition temperature than the standard notch specimen

curve, but the bend angle above the transition tempera turc is considerably lower than that for the standard

notch. _{However, the two tests which were made with the}

subcritical region at the notch bottom indicate that a

transition curve through these points might fall at a

higher temperature than that found for the standard

specimen0 _{The somewhat similar impact tests conducted} by Schnadt as dseribed by R0 Week (11+) also show the

suberitically heated region to be more subject to

brittle faIlure0 Consequently9 if these indications are

trie the region which is heated below the critical tem

perature plays an important role in the behavior of the

standard notch bend test on plate specimens even though

the cracks whIch eventually lead to failure may orIginate

I-4 70 60 50 40 30 uJ -J

c20

z 4 o

z

w Io o

-31-.

STRIiCTURES AT NOTCH BOTTOM

HEATED HEATED BELOW ABOVE CRITICAL CRITICAL D WELD METAL STRUCTURE STRUCTURE

,

/

/

/

I

I

I

/

-o

I

/

I

f

'J

/

-00

-60

-20

20 60 loo TESTING TEMPERATURE°F

FIG. 14:

EFFECT OF TEMPERATURE ON DUCTILITY

OF SINGLE BEAD-ON-PLATE SPECIMEN

(FOUNTAIN AND STOUT)

CONCLUSIONS

L At the surface level of a C steel weidment a zone of minimum ductility was located at about Of inch

from the weld centerline

2 The eccentric notch tensile tests at the plate

surface showed the same behavior as previous midthickness

tests thus eliminating any difference due to gross in

homogeneity of the plate.

30

The zone of low ductility was aodefined by

means of concentric notch tensile tests at low temperature0 The urinotched tensile test was not sufficiently severe to detect variations in ductilïty across welded plate

FUTURE WORK

As one approach to the problem of embrittlement cf

steel when welded

this laboratory is at present engaged

In ari investigation in which areceived C steel plate

is being subjected to various subcritical isothermal temperatures for varying periods of time and employing

various rates of cool0 Tests to date have shown that

the transitIon temperature can be raised by this means9 even higher than the highest transition temperature pr

-33

that this investigation will give an insight into the basic mechanism which is responsible for the embrittling

of steel when welded and suggest possible methods of

ACKNCWLGMLNT S

Acknowledgment is given to the Battelle Memorial

Institute for welding the plate and particularly9 to

Messrs. C B. Voldrich P. J. Rieppel, and

M0 F0

Orman

for their aid.

The authors are also indebted to Mr0 R0 G. Howe

,3 5...

BIBLIOGRAPHY

l _{G. Sachs9 L. J0 Ebert9 and A.}

_{W, Dana}

uThe

_Funda

mental Factors Influencing the Behavior of Welded

Structures Under Conditions of Multiaxial Stress9 and Variations of Temperature9 Stress Concentra

tion and Rates of Strainu,

_{Navy Departments Bureau}

of Ships Contract NObsJ+54709 Serial No0

_SSC2+9

May 10, 19+9

2. L. L Klingler9

L0 J0

_{Ebert and W M0 Baldwin,}

Jr.,

t'The Fundamental Factors Influencing the Behavior

of Welded Structures under Conditions of _Multiaxial

Stress9 and Variations of Temperature St,ress

Concen-tration and Rates of Strain's, Navy Department9 _Bureau

of Ships Contract NObs-+51+7O, Serial No0

_SSC3

November 289 19I9°

30 Technical Progress Report of the

Ship Structure

Committees We1dng Journal9 Vol0

_{13 (Juy 198), p}

377s381+s

G. Sachs9 L0 J0 Ebert

_{and We}

_{F0 Brown9 Jr.9}

Com-parison of Various Structural Alloy Steels by Means

of the Static Notch-Bar Tensile Testo, _{Trans0 Am0}

Inst0 Mining & Met0 Engrs. Vol0 171 _{(19+7), p0}

6O-621

G.

Sachs, J.

_{D0 Lubahn L.}

J. Ebert9

_{Notched Bar}

Tensile Test Characteristics of Heat _{Treated Low Alloy}

Steels's, Trans0 Am0 Soc. Metals, Vol.

₃₃

_{(19+) pp.}

3+0-395'.

N. Grossman and P0 R. Shepler, uThe Effect of Welding

Technique on Brittle Transition Temperature' _Welding

Research Supplement9 Vol0 12 (June l9+7), pp. 32ls-331s.

N. Grossman and C. W MacGregor _{The BrIttle}

Transi-tion Temperature of VarIous Lowc.Carbon Steels Welded

by the

_{Same Method",}

_{Welding Research Supplement,}

VoL 13 (May 191+8) Po _267s-271s0

E. F4 N!ppes

_{and W.}

F0

Savage9

_{'Tests of Specimens}

Simulating Weld Heat-Affected Zones9 _{Welding Research}

3 6

9° A B0 Kinzel, "Ductility of Steels for Welded

Structures", l9+7 Campbell Memorial Lecture, Welding Research Supplement, Vol0 13 (May l9-f8)

2l7s-23+s0

10, R0 D0 Stout9 J0 L0 MacGeady, J0 F0 Libsch and G0

E0 Doan, "Effect of Welding on Ductility arid. Notch Sensitivity of Some Ship Steels", Welding Research

Supplement, Vol0 12 (l97)

335s357s0

110 F0 R0 Baysinger, P0 J0 Rieppel9 and C0 B0 Voldrich,

"Evaluation of Improved Materials and Methods of Fabrication for Welded Steel Ships, "Final Report for Ship Structure Committee, Bureau of Ships Contract Nobs'-5OJ)+8, Serial No0 SSCf5, December

20, 195L

12. R0 D0 Stout and L0 J McGeady, "Notch Sensitivity

of Welded Steel Plate", Welding Research Supplement, Vol0 J)+ (l99) pp0 ls-9s

l3 R. W0 Fountain and R0 D. Stout, "Relative

&train.-Aging Tendency of Weld and Base Metal"9 Welding Re-search Supplement) Vol. 16 (195'1)

1+ R0 Week, "An Account of M0 Henri M0 Schnadts Ideas

on the Strength of Materials, and His Testing Methods",

Reports of Progress, Welding Research Counci1 Vol0 5

.'3 7',

APPE

IX

Table I

Eccentric Notch Tensile Data at the Surface Ley.l "Cu

Steel Weldment 1000F preheat,

Distance from Testing Eccentric

Weld Centerline Temperature Notch Strength

Inches OF 1000 Psi

0.0

-80

ii68

000

-8O

_1185'

000

_111-3

0.].

-80

_l213

0.1

-80

ll86

001

-80

117.3

0.2

8o

₁₁₈₉

0.2

-80

₁₁₇₎₊

0.2

-80

_120.9

0.3

-80

₁₁₀₉

0.3

-80

_1l07

0.3

-80

0.35'

8o

10000

-80

36.8

01

_.=.80

_35.3

o.+

-80

37.0

005'

-80

0.5'

-80

₃₈₇

005

-80

Lf309

0.5

-80

0075'

-80

32.6

0.75

-80

_35.+

0.75

-80

_35.2

100

-80

1.0

-80

₃₅₀₂

100

-8o

₅₉₀₃

-38..

a Specimens of same geometry but

taken from the center of the

plate.

TABLE I (Continued)

Distance from Testing Eccentric

Weld Centerline Temperature Notch Strength

Inches 0F 1000 Psi

200

RT 90.1+

2.0

II

87.3

2.0 RT

89.1

2.0

97.1 *

2.0

9600 *

2O

RT

9606 *

2.0 -1+0 6+.o 2.0 -1+0

6703

2.0 -1+o

68.7

2.0 -1+0 71+03

2.0

-1+o

73.7

2.0 -1+0 _73A1

2.0

-1+0

76.7

2.0 -1+0

68.1

2.0

-60

70.6

2.0 -60

71.2

2.0

-60

60,0

2.0

-80

51,6

2.0 -80 2.0 -80 1+608 2.0 -80

37.1

2.0

-80

58.9

2.0

-80

1+3.8 2.0 -80

58.1

2.0 -80

31.0

2.0

-110

35.7

2.0

-110

36.3

20

-110

2.0 -110

3305 *

2.0 -110

35.3 *

2.0 -110 1+002 * -20

86.7

-20

8703

-20

8106

-+O 71+.3 -1+0

8003

-60

6200

-60

80.1

-39.-TABLE II

Uririotched Tensile Data at the Mldthickness

A Steel Weidment 100°F Preheat

s Distance from Weld Centerline Inches Test Temperature Tensile Strength 1000 Psi Reduction in Area Per Cent 0.0

-110

882

'300

0.0

-P110

87.9

_63.7 0.35

-110

915

'8. 5

0.35 -110

88.5

_53.1

'10

RT Ouo'-Q

₅₆₀₅

+00

685

₅₆₀₅

'10

-80 _{8302 52.7} LF.0

-8o

82.'

52 ₃ -150

9Z2

50.8

f.0

-1 5'O 92.0

_'90

IF00 _-321

l'2l

1.5

'00

-321 1L1]0 101

Concentric Notch Tensile Data at the M1dthickn

TABLE III

A Steel Weidment 100°F Preheat

Ductility in Area Cent Distance from Weld

Centerline

Inches

Test

Temperature °F Concentric Concentric Notch Notch

Strength

Red.

1000 Psi Per 000 -110 119 19)+ 000 -110 118 _15.6 000 -110 121+ 1805 0015 -3-J-0. 128 1001

015

110 121+ 900 o 15 110 129 1902

035

-1+0 112.2 501

035

-1+0 10906 2.8

035

112.1

67

o 3 5

-1+0 91f7 3.0

035'

-110 io8. 102

035

:110 1090

1.1

035

-110 3-loo 0.8

035

-110 102.5

1005

035

-110 102.+ 1028 0035 -110 92.

03

0es -1J0 9703 1 69 005 -110 103.1 3.1+6

O5

-110 100.3 2.30

20

o

9707 l+ 02

20

o

96.3 lo .1+

20

99 1 1002 2.0 -1+0 9703 10cl 2.0 -1+0 _96.7

81

2.0 -80 91+08 2.0 -80 9201 5 6 2.0 -80 9100

20

-110 9300 501+

20

-110 9207 2.8

20

-110 92.3 3.2 2.0 -110 9007 1+98

20

-110 91+00

5023

2.

- 1f₅ 102. 305 2.0 -150 102 0.8 200 -152 9901+ 3021+ 2.0

-155

103 08

203

2.0 -200 9600 0081+ 200 -200 931+ 0010 2.0 _-323,

₉₆₃

005

1f00

o0

6.0 6.0

rr

o

o

j+o

j+1-TABLE III (Continued)

Distance from Test Concentric Concentric

Weld Centerline Temperaturc Notch Notch Ductility

Inches Strength Red0

in

Area

er

Cent 90

2

99.

)+

1035

98.1

9600

100.0

Ô'7_{1/ 0}

000

2l+

223

1309

1000 15.1

102

9.3

9.6

2.0

321

680

2.0

32l

89.0

20

32l

62

+

2.0

3 21 J Jo

00

9003

-2-TABLE IV

Eccentric Notch Tensile Data at the Midthickness

A Steel Weidment 1000F Preheat

Distance from Weld Centerline Inches Te st Temperature Eccentric Notch Strength 1000 Psi 000 110

1191

0.0 110

1161

000 110

1222

035

-110 31.)+

035

-110