10
8/10/2019 Effect of Columbium and Vanadium on the Weldability of HSLA Steels http://slidepdf.com/reader/full/effect-of-columbium-and-vanadium-on-the-weldability-of-hsla-steels 1/10 Effect of Columbium and Vanadium on the Weldability of HSLA Steels Excellent low-temperature HAZ and weld-metal toughness can be obtained in a variety of HSLA steels containing Cb and V BY E. G. SIGNES AND J. C. BAKER MARY. A comprehensive study  high- etal toughness. Results were based on a series of 500  Si-Al-ki I  led low-sulfur steels  con e looked at compositions in which  respectively. Much of the data was statistically  Equations were developed dicted as a func Cb and V. Metallography In general, good weld-metal and  The main findings of the study 1.  HAZ toughness increased with presented at the AWS 60th Annual  2-6,  1979  G.  5IGNES  is a  Research  Engineer—Prod  I C  BAKER  is Research  Metallurgy, Bethlehem Corporation, Homer  Research  Labora 2.  Three different electrode/flux combinations gave good weld-metal toughness in most cases. At low C levels a Ti-B electrode produced exceptionally tough weld metal for all microalloy combinations, even in steel containing 0.15% Cb. Materials and Welding Procedures The compositions of all plates tested are given in Table 1. The first 15 heats listed in this table were chosen to fit a partial three-level factorial experimen tal design, known as a Box-Behnken design.'  These heats were based on variations in C, Cb and V levels. The levels for the fifteen heats were: C  ( ) 0.18 0.13 0.08 Cb ( ) 0.06 0.03 Trace V  ( ) 0.10 0.05 Trace Heats 16 and 17 in Table 1 also fall within or close to the above composi tion ranges but were not part of the factorial design. Heats 18 and 19 contained Cb contents in excess of 0.06%. All heats were air-induction-melted 500 lb (225 kg) laboratory heats. Also, all heats were slabbed to a thickness of 4 in. (102 mm), reheated to 2000 F (1090 C), and control-rolled to  in. (19 mm) plate over the temperature range of 1620 to 1300 F (880 to 700 C). Referring to Table 2, three consum able combinations were used: 1.  A 0.5% Ni-0.5% Mo electrode (coded 44) selected because earlier testing had shown that it produces slightly better toughness than a 0.5% Mo electrode and substantially better toughness than a straight C-Mn elec trode.  This electrode was used with an Table  1 —Plate  Composition, % Heat' Code Mn Cb I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 112 123 132 121 211 213 233 231 312 323 332 321 M1 M2 M3 131 333 141 151 0.085 0.078 0.070 0.083 0.14 0.13 0.15 0.14 0.18 0.18 0.19 0.24 0.12 0.13 0.14 0.077 0.19 0.077 0.089 1.24 1.49 1.37 1.41 1.47 1.36 1.45 1.25 1.51 1.39 1.45 1.45 1.40 1.40 1.44 1.41 1.44 1.41 1.43 < 0.005 0.028 0.059 0.027 < 0.005 < 0.005 0.056 0.059 < 0.005 0.028 0.068 0.028 0.031 0.028 0.027 0.055 0.053 0.12 0.15 0.047 0.095 0.048 0.002 < 0.002 0.10 0.10 0.002 0.052 0.093 0.052 < 0.002 0.048 0.050 0.050 < 0.002 0.11 < 0.002 0.002 All heals con tain  £  0.01% P, 0.004/0.006% S, 0.20/0.30% Si, 0.025/0.040%  Al,  0.005/0.008%  O  and  0.007/0.011  N. WELDING RESEARCH SUPPLEMENT I  179-s

Effect of Columbium and Vanadium on the Weldability of HSLA Steels

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Page 1: Effect of Columbium and Vanadium on the Weldability of HSLA Steels

8/10/2019 Effect of Columbium and Vanadium on the Weldability of HSLA Steels

http://slidepdf.com/reader/full/effect-of-columbium-and-vanadium-on-the-weldability-of-hsla-steels 1/10

E f f e c t o f C o l u m b i u m a n d V a n a d i u m

on the Weldab i l i t y o f HSLA Stee ls

Excellent low-temperature HAZ and weld-metal

toughness can be obtained in a variety of HSL A steels

containing Cb and V

BY E. G. SIGNES A N D J. C. BAKER

MA R Y . A co mp r e h e n s i ve s t u dy

  h i g h -

e ta l toughness.

Results were based on a series of 500

 Si-Al-ki I led low -su l fur stee ls

  c o n

e looked at com pos i t i ons i n wh ich

  respect ive ly.

Much of the data was sta t ist ica l ly

  Equa t ions were deve loped

dict ed as a func

Cb and V. Me ta l log raph y

In genera l , goo d we ld -m e ta l and

  The main f ind ings of the study

1.

  HAZ toughnes s increased w i th

presented at the AWS 60th Annual

  2-6,

  1979

  G. 5IGNES  is a Research

  Engineer—Prod

 I

C

  BAKER  is Research

  Metallurgy, Bethlehem

Corporation, Homer Research  Labora

2.   Th ree d i f fe ren t e lec t rode / f l ux

co m b i n a t i o n s g a ve g o o d w e l d -m e t a l

tough ness in most cases. At lo w C

leve ls a T i -B e lec t rode pro duc ed

excep t iona l l y tough we ld me ta l fo r a l l

microa l l oy comb ina t ions, even in s tee l

conta in ing 0 .15% Cb.

M a t e r i a l s a n d W e l d i n g

P r o ced u r es

The composi t ions o f a l l p la tes tested

are give n in Table 1 . The f i rst 15 heats

l isted in this table were chosen to f i t a

pa r t i a l th ree - leve l fac to r ia l expe r imen

ta l des ign , known as a Box-Behnken

des ign . '

  These heats were based on

variat ions in C, Cb and V levels. The

levels for the f i f teen heats were:

C

 ( )

0.18

0.13

0.08

Cb ( )

0.06

0.03

Trace

V  ( )

0 .10

0.05

Trace

Heats 16 and 17 in Table 1 also fall

w i th in o r c lose to the above compos i

t ion ranges but were not part of the

factorial design. Heats 18 and 19

conta ined Cb contents in excess of

0.06%.

A l l heats were a i r - i n duc t ion - me l ted

500 lb (225 kg) laboratory heats. Also,

al l heats were slabbed to a thickness of

4 in. (102 m m ), rehe ated to 2000 F

(1090 C), and contro l -ro l led to  in.

(19 mm) p la te over the temperature

range of 1620 to 1300 F (880 to 700

C).

Referr ing to Table 2 , three consum

ab le comb ina t ions were used :

1.

  A 0.5% N i -0 .5% M o e lect ro de

(coded 44) selected because earl ier

test ing had shown that i t produces

sl ight ly bet te r toughn ess than a 0 .5%

Mo e lect rode and substant ia l ly bet ter

toughne ss than a st ra ight C- Mn e lec

t r ode .

  Th is e lect rode was used wi th an

Table

 1 —Plate

  Composit ion, %

Heat' Code Mn Cb

I

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

112

123

132

121

211

213

233

231

312

323

332

321

M 1

M 2

M 3

131

333

141

151

0.085

0.078

0.070

0.083

0.14

0.13

0.15

0.14

0.18

0.18

0.19

0.24

0.12

0.13

0.14

0.077

0.19

0.077

0.089

1.24

1.49

1.37

1.41

1.47

1.36

1.45

1.25

1.51

1.39

1.45

1.45

1.40

1.40

1.44

1.41

1.44

1.41

1.43

< 0.005

0.028

0.059

0.027

< 0.005

< 0.005

0.056

0.059

< 0.005

0.028

0.068

0.028

0.031

0.028

0.027

0.055

0.053

0.12

0.15

0.047

0.095

0.048

0.002

< 0.002

0.10

0.10

0.002

0.052

0.093

0.052

< 0.002

0.048

0.050

0.050

< 0.002

0.11

< 0.002

0.002

A l l h e a l s c o n t a i n   £  0 .01 % P, 0 .004/0.006% S, 0 .20/0 .30% Si , 0 .025/0.040 %

  A l,

  0 .005/0.008%  O  a n d  0.007/0.011  N.

W E L D I N G R E SE A RC H S U P P LE M E N T I 179-s

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Table 2-C omp osit ions of Submerged Arc W elding Consumables, %

Electrode compositions

Code

44

120

TB

Code

851

0091

121

' CaO +

Type

0.5%Ni-0.5%Mo

2.5%Ni-0.5%Mo-0.5%Cr

0.03%Ti-B-0.25

o/

oMo

CaF.. + MgO + K.O +  Na,0  +  I

C

0.14

0.07

0.059

C

0.002

0.190

0.350

i  ( M nO + 1

SiO, +  2  (ALO, + TiO + ZrO.)

M n

2.09

1.55

1.32

S iO,

42.8

36.0

10.7

eO)

S

0.011

0.008

0.006

A L O ,

2.6

3.2

17.3

P

0.019

0.006

0.003

Fe..O,

0.39

0.20

1.90

Si

0.05

0.35

0.03

C a O

37.5

46.3

6.6

Al

0.023

0.025

0.024

M o

0.49

0.55

0.25

N i

0.60

2.40

0.06

F l ux c om pos i t i ons

M g O

0.40

0.36

31.70

M n O

0.41

0.14

1.10

T i O ,

11.50

4.40

0.86

Ti

-

-

0.03

N a . O

0.05

5.10

0.78

li

-

-

0.010

CaF.,

4.5

9.8

24.1

Cr

-

0.45

-

Bas ic it y ind ex ' '

0.85

1.55

3.13

ac id f lux ( coded 851) because more-

basic f luxes d id not produce bet ter

t o u gh n e s s w i t h o u r we ld in g p r o c e

dures.

2.  A 2 .5% Ni -0 .5% Mo-0 .5% Cr e lec

t rode ( coded 120) used in combina t ion

with a less ac id ic f lux (coded 0091) .

3 . A 0 .03% T i -B-0 .25% M o e lec t rod e

(coded TB) used wi th a bas ic f lux

(coded 121) .

A l l we ld i n g wa s d o n e u s in g a Sc o t t -

c o n n e c t e d t a n d e m A C / A C s u b

merged-arc system. One pass per s ide

wa s d e p o s i t e d i n t o a d o u b le - V j o i n t .

Except where o therwise no ted , t he

p la tes we re we ld ed wi th a hea t inpu t

of 75  k j / i n .  (3 .0 k j /m m ) . A few p la tes

we r e we ld e d w i t h 4 5 a n d 1 0 0   k j / i n .

(1 .8 and 3 .9 k ) /mm) . These we ld ing

proced ures , w h ic h resu l t ed in  d i l u

t ions o f 60-65%, had the fo l low ing

parameters :

Lead head

Trai l head

Current,

A

950

700

Voltage,

V

30

35

Table 3—Data  Used in Statistical Analysis

Toughness

  propert ies '

,

 at —50 F (—46 C)

Co

C

Box -Behnk

0.08

0.08

0.07

0.08

0.14

0.13

0.15

0.14

0.18

0.18

0.19

0.24

0.12

0.13

0.14

A d d i t i o n a l

0.08

0.19

m

 pos i t i on ,

Cb

en Heats :

0

0.03

0.06

0.03

0

0

0.06

0.06

0

0.03

0.07

0.03

0.03

0.03

0.03

Heats

0.06

0.05

%

V

0.05

0.10

0.05

0

0

0.10

0.10

0

0.05

0.09

0.05

0

0.05

0.05

0.05

0

0.11

Code

112

123

132

121

211

213

233

231

312

323

332

321

M l

M 2

M 3

131

333

Tens i le

YS

ksi

(MPa)

54.3

(374)

76.8

(529)

70.4

(485)

64.3

(443)

54.6

(376)

63.4

(437)

69.5

(479)

61.2

(422)

64.7

(446)

75.5

(521)

68.9

(475)

68.0

(469)

68.8

(474)

65.2

(454)

67.3

(464)

69.7

(481)

77.0

(531)

proper t ies

1

UTS

ksi

(MPa)

67.7

(467)

82.1

(566)

76.8

(529)

72.5

(500)

73.6

(507)

79.3

(547)

84.0

(579)

74.3

(512)

84.1

(580)

90.3

(623)

87.3

(602)

87.8

(605)

78.9

(544)

77.9

(537)

81.6

(563)

76.6

(528)

94.6

(652)

Base meta l CVN,

I t - l b

(I)

67.5

(91.5)

65.5

(88.8)

104.5

(141.7)

83.0

(112.5)

42.5

(57.6)

35.0

(47.5)

40.0

(4.7)

56.5

(76.6)

35.0

(47.5)

34.0

(46.1)

43.0

(58.3)

29.0

(39.3)

71.5

(97.0)

63.0

(85.4)

61.5

(83.4)

125.5

(170.2)

43.5

(59.0)

H A Z C V N ,

f t - l b

(I)

45.7

(62.0)

40.0

(54.2)

57.7

(78.2)

46.8

(63.5)

29.0

(39.3)

42.0

(57.0)

15.0

(20.3)

34.5

(46.7)

47.0

(63.7)

13.0

(17.6)

8.5

(11.5)

22.5

(30.5)

32.5

(44.1)

10.7

(14.5)

22.0

(29.8)

72.1

(97.8)

11.1

(15.1)

4 4 /8 5 1 ,

f t - l b

(I)

50.0

(67.8)

32.0

(43.4)

28.0

(33.0)

30.5

(41.4)

32.0

(43.4)

45.5

(61.7)

50.5

(68.5)

39.0

(52.9)

42.0

(57.0)

49.3

(66.9)

29.0

(39.3)

31.3

(42.4)

61.5

(83.4)

43.0

(58.3)

43.0

(58.3)

102.3

(138.7)

22.4

(30.4)

We l d m e t a l

120 /0091 ,

f t - l b

(I)

60.7

(82.3)

82.0

(111.2)

52.7

(71.5)

87.5

(118.7)

84.0

(113.9)

88.5

(120.0)

28.8

(39.1)

77.5

(105.1)

63.0

(85.4)

29.2

(39.6)

52.7

(71.5)

30.7

(41.6)

52.7

(71.5)

46.0

(62.4)

54.3

(73.6)

96.0

(130.2)

42.0

(57.0)

T B /

 12 1

f t - l b

(1)

115.0

(155.9)

118.3

(160.4)

138.0

(187.1)

139.0

(188.4)

49.0

(66.4)

66.3

(89.9)

40.0

(54.2)

77.3

(104.8)

15.4

(20.9)

60.3

(81.8)

95.3

(129.2)

1.5

(2.0)

74.7

(101.3)

64.3

(87.2)

59.3

(80.4)

154.0

(208.8)

124.0

(168.1)

YS—Yield st rength; UTS—ultimate  tensile strength.

CVN— Chapry V—notch; HAZ—heat-affected zone.

180-s  I JUN E 1979

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 4—Results

  of Multiple Linear Regression Analysis

  B,(%

  Cb) +

  B,(%

 V) +

  B,,(%

 C

3

) +  B.,.,{ Cb

3

) +

  B

M

(%

 V

3

)

4- B,,( C x  %  Cb )  I B„(% C x  %  V)  4-

 B

M

(%

 Cb x  %  V)

(4) -50 H HAZ - CVN energy at -50F   (-46C)

(5) -5044 weld metal (44/851) CVN energy at -50F   (-46C)

-50F (-46C)  (6) -501 20 we ld metal (120/0091) CVN energy at -50 F (46C)

(7) -50TB weld metal

  (TB/121)

  CVN energy at -50F  (-46C)

Coeff icients of above equat ion'

U n i t s

ksi

ksi

f t - l b

f t - l b

f t - l b

f t - l b

f t - l b

R

.9461

.9663

.9752

.9651

.6147

.9022

.9600

B„

61.75

66.98

157.0

99.09

Not inc

96.89

421.8

SErr

3.188

2.717

8.838

7.225

21.35

13.42

19.08

B,

- 1 6 8 . 9

- 4 0 . 6 6

- 1 2 2 2

- 846 . 2

B

2

674.3

347.8

1172

209.4

B„

  B,, B

2

,

57.53 748.6 -5 27 7

14.22 542.6 -21 21

- 323 . 3 2765 - 47 01

-24 5.5 2680 11720

uded s i nc e ana l y s i s s howed no m ean i ng f u l c o r re l a t i on

- 18 . 18

- 3 9 1 5

- 4 3 0 . 3

- 1 5 4 4

- 68 5 . 0 - 933 . 9 8253

-1 47 3 8306 6550

Sta t i s t i ca l parameters

F

6.643

10.94

15.12

10.56

0.47

3.40

9.14

P

0.0103

0.0023

0.0008

0.0026

0.8540

0.0602

0.0040

C o r r e l a t i o n

1 0

G o o d

Exce l len t

Exce l len t

Exce l len t

N o n e

Fair

Exce l len t

B„

8.8

41.3

- 3 0 8 5

1291

6588

1963

B„

- 1 4 2 1

- 1 1 2 9

- 3 6 4 9

- 6 3 7 1

671.5

12800

473.4

547.3

3964

1684

1198

10743

B,;,

- 485 . 2

95.30

- 1 6 4 2

- 5 1 5 4

- 9 3 0 8

- 4 0 8 6

  convert to SI units, multiply coefficients for: ksi X 6.895 to get MPa and ft- lb X

 1.356

  to get J.

  correlation coefficient;  SErr—standard  error of estimate;

 F—F-ratio; P—Probability

  that the variance can be explained by change.

  define d as: Excellent: P <  0.01 Fair:  0.05 < P£0.1 5

Good:

  0.01 < P  £ 0 . 0 5

  Poor:

  0.15 < P

Tensi le, Charpy and hardness tests

  (12.8 mm) tensi le specimens were

Charpy tes t ing o f base meta l , HAZ

 we ld - m e t a l s p e c im e n s we r e t a k

  we ld .

0 F (—46 C) . To inc lud e as mu ch of

  Va

  in . (1.5 m m)

wh ere the no tch inc lu ded 50%

ld me ta l and 50% HA Z. A l l H AZ and

Hardness t raverses of selected welds

A number o f we lds were s tud ied

Th e q u a n t i t a t i v e o p t i c a l

s is was don e w i th a TAS  ( Tex

An a ly z in g Sy s te m , a q u a n t i t a t i v e

s and Discus sion

Th is sec t ion dea ls ma in ly w i t h t he

chemis t r y e f f ec t s on the mechan ica l

p roper t ies o f base meta l , HAZ and

weld metal of heats made to the Box-

Behnken des ign . Chemis t r y e f f ec t s in

the st ra ight -Cb heats as wel l as the

e f fec t s o f coo l ing ra te on no tch tough

ness are then discussed.

Heats in Box-Behnken Design

A mu l t ip le l inear regress ion p rogram

was employed to de te rm ine the re la

t ionsh ip o f seven dependent var iab les

to C, Cb and V. These var iables were:

1.  Base-metal y ie ld s t rength (YS) .

2.  Base-meta l u l t im ate tens i le

st rength (UTS) .

3 . Base-meta l Charpy V-n o tch

(CVN ) energy at -5 0 F ( - 46 C) .

4.  HAZ CVN e n e r gy a t - 5 0 F ( - 4 6

Q.

5 . W e ld - m e t a l CVN e n e r gy a t - 5 0 F

( -46 C) f o r  44/851 electrode/flux

c o m b i n a t i o n .

6 . W e ld - m e t a l CVN e n e r gy a t - 5 0 F

( -46 C) f o r 120 /0091 e lec t rode / f lux

c o m b i n a t i o n .

7 . W e ld - m e t a l CVN e n e r gy at - 5 0 F

( -46 C) f o r TB/121 e lec t rode / f lux

c o m b i n a t i o n .

The equat ion express ing the re la

t i o n s h ip wa s g i v e n t h e f o l l o w in g

f o r m :

De pe nde nt Var iab le = B„ +  B,

+ B., (C b)   4-  B, (V) +  B,,  (C

3

) +

(Cb

3

) 4-  B„  (V

3

)  4-  B„ (C x Cb)  4-

(C x V) +  B.„  (Cb x V)

(C)

wh ere C, Cb , and V = w t % of C, Cb

and V in the base metal .

Two add i t iona l hea ts were

made-0.08% C, 0.06% Cb, 0% V, and

0.18% C, 0.06% Cb and 0.10% V - o n the

basis of the or ig inal analys is of the 15

heats in t he Box-Behnken des ign . The

data ob ta ined f rom these hea ts were

combined wi th t hose o f t he 15 o r ig ina l

heats.

Tab le 3 represen ts the co mb ine d

data; their ana lys is is g iv en in Table 4,

wh ich p resen ts t he coe f f ic ien ts f o r

each equat ion and also several s tat is t i

cal parameters associated with

t h e m— n a me l y ,

  t h e m u l t i p l e c o r r e l a

t ion coe f f i c ien t , t he s tandard e r ro r o f

es t imate , t he F- ra tio , and the f rac t ion

o f t he var iance exp la inab le by

chance .

In the last column of Table 4, cor re

la t ion is de f ine d as: ex ce l le n t i f

P <  0.0 1, i.e., if  >  99% of the var iance

can be exp la ined by the C, Cb and V

le v e l s ; go o d fo r 0.01  < P <  0.05; and

fa ir for 0.05 < P <  0.15. In one case,

the toughness o f t he 44 /851 we ld

meta l , t here was no mean ing fu l co r re

la t ion , P be ing 0 .85. Conse que nt ly , t he

e le m e n t s a d d e d f r o m t h e we ld in g

c o n s u m a b le s a n d / o r t h e i r i n t e r a c t i o n

wi th t he base meta l were p robab ly

more s ign i f i can t t han the base-p la te

c o m p o s i t i o n .

For easier understanding, a ser ies of

curves based on the regression data

we r e p lo t t e d . For ea c h d e p e n d e n t  var i

able, n ine curves of predic ted isolevels

W E L D I N G R E S EA R CH S U P P L E M E N T  I

 181-s

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  l  HAZ

-fe-;'

  ;

*f l

,..*;:  ;-^».y«',....*, .-  -; . <.-^..,r.r  .

,:

  3 >

^ A   ~**

 

. ^ ^ t n * i ^

-**

1

;;

<kmm

  y - - ~ *  > > . . v ; •

i

w:><s

,

u

3

-w(T^;

;

.

  4—HAZ  microstructures of tow an d

  0.06 Cb and

 A-heat

  132

 (0.07

C, 58 it-lb at

F); B-heat 332 (0.19 C, 8 ft-lb at

  Nital etch, X250 (reduced

  33

on

t c o n t a in e d p r e d o m i

the b a in i t e co l ony s ize

and the s t ruc tu re becam e

re la th l ik e, as seen in Fig. 4 w hi ch

2- bo th a t a 0 .06% Cb an d 0 .05% V

250

o

>

<n

tn

UJ

Q

or

<

X

N

<

?

-D

i

X

<

^

240

230

2 2 0

2 I 0

?or

I 9 0

Legend

0.08  %C heats

0.13  % C heats

(D

  V///A

  0.18  %C heats

IO 20 30 40 50 60

HAZ TOUGHNESS, f t - lb at

70 80

- 5 0 F ( - 4 6 C)

Fig.

 5—HAZ

 toughness as a function of max imum hardness (multiply ft-lb by

1.356

  to get I)

level but wi th C conte nts of 0.07% and

0.19%, respec t ive ly . On the o th er han d,

wh en the C is cons tan t , t he var ia t ion in

the Cb and V levels has l i t t le in f luence

on the m ic ros t ruc tu re .

Accord ing to var ious inves t iga to rs ,

when coo l ing ra tes a re re la t ive ly s low

so tha t g ra in coarsen ing and p rec ip i t a

t ion take p lace, e i ther Cb or V can

decease the HAZ toughness .

  C o n

verse ly , when coo l ing ra tes a re re la

t ive ly fast, the effe ct o f C b or V 'is to

impro ve the HA Z toug hness as a resu lt

o f g ra in re f inem ent and p roe u te c to id

fer r i te suppression. P.H.M. Har t

  et al.

summar ized several of these studies

cover ing a range o f coo l ing ra tes and

Cb ,  V and o ther a l loy ing add i t ions .

3

O u r c o o l i n g t im e o f 25 s e c o n d s f r o m

800 to 500 C (1472 to 932 F) result ing

f rom the 75

  k j / i n .

  (3.0  k j /mm)  c o n d i

t ions was near the fast end of the

repor ted range . A t t h is coo l ing ra te ,

bu t depend ing on the C leve l , e i t her

Cb or V inc reased the HAZ toughness

in our s tudy . However , in con t ras t t o

Har t , w ho repor te d tha t V was m ore

e f fec t ive as t he C con te n t was

lo we r e d , we f o u n d t h a t V wa s m o r e

ef fect ive at a h igher  C-0.18%.  Cb was

more e f f ec t ive a t a lower C

  lev-

e l - 0 . 0 8 % .

Ext ract ion repl icas and th in f i lms

examined in t he TEM d id no t show

any p rec ip i t a tes t ha t wou ld exp la in t he

HAZ toughness var ia t ions . L ikewise ,

0 1 0

120/0091

  Weld Meta l

  Toughness, f t -l b a t - 5 0 F

C=0.08  %

0 1 0

120/0091  Weld Metal Toughness,ft-lb  a t - 5 0 F

C =

  0 . 1 8 %

0.03 006

COLUMBIUM

 6-CVN

  energy

 levels

 at -50

  F

 (-46

  C)

  in ft-lb ol

  120/0091

  weld

  0.08

C (multiply by

 1.356

  to get I)

0 0 3 0 0 6

COLUMBIUM

Fig. 7-CVN

  energy levels at -50

  F

 (-46

  C)

  in ft-lb ol  120/0091  weld

metal for

  0.18

C (multiply by

  1.356

  to get I)

W E L D I N G R E S EA R C H S U P P L E M E N T I 183-s

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TB/121 Weld M etal Tou ghn ess, f t - lb  at -

C =  0 . 0 8 %

5 0 F

TB/121 Weld Metal

  Toughness,ft-lb

C = 0 1 8 %

a t - 5 0 F

2

a

<

<

>

0 0

0.03

COLUMBIUM

0.06

0

 03

CO L UM BI UM

0.06

Fig.

 8-CVN

  energy levels

 at -50

 F

 (-46

 C )

 in

 ft-lb

  of

 TB/121 weld

metal  lor

 0.08

C (m ultiply

  by 1.356 to

 get I)

Fig.

 9-CV N energy

  levels

 at -50F (-46

 C)

 in

 it-lb

  of

 TB/121 weld

metal

 for 0.18

C (m ultiply

  by

 1.356

 to

 get I)

no  Cb-

 or

 V-be ar ing p rec ip i t a tes we re

f o u n d

  on

  f rac tu re sur faces w he n

  the

SEM

 was

 used . Ho we ver , t ha t p re c ip i

t a t ion  was o c c u r r i n g  in the HAZ can

be in fe r red f rom

  the

  c o m p a r i s o n

  of

m a x i m u m

  HAZ

 h a rd n e ss w i t h t o u g h -

§:m^'MM^M

Fig.

 10-Weld-metal

  structures

 of

 steel

  132

(0.07

C, 0.06% Cb,

 0.05

V):

  A-welded

with

  120/0091

  (53 ft-lb

 at -50 F);

  B-welded

with

  44/851

 (28 ft-lb

  at -50

  F). Nital etch,

X50

  (reduced

 20

on

  reproduction)

ness  (Fig.

  5),

 wh e r e t h e r e

  is a

 cor re la

t i o n ,

  e v e n w i t h i n l i k e

  C

  levels .

  As for

the base plates, we  f o u n d  no  cor re la

t ion  of  hardness w i th t oughness .

Canadian researchers

  di d

  f ind p re

c i p i t a t i o n

  in the

  f o rm

  of CbC and

V(C,N)  in the

 HAZ

 of

 a

 0.09% C b

 and

 a

0.09% V s tee l , r espec t ive ly , but o n l y  in

very s lowly coo led we lds .

3

  On the

other han d, t hey fou nd tha t

  the

 smal l

size

 of the

 HAZ

 in

 we ld s p r o d u c e d

 by

c o n d i t i o n s s im i l a r  to  ours p resen ted

in s u r m o u n t a b le s a m p l i n g p r o b le m s .

Weld Metal.

  The

  r e l a t i o n s h ip

  of

t o u gh n e s s  to  base-me ta l che mis t r y

was stat is t ica l ly re levant  for the 120/

0091

  and

 T B / 12 1 c o n s u m a b l e c o m b i

na t ions

  bu t not for the 4 4 / 8 5 1 .

  W i t h

one except ion , t oughness us ing 44 /851

c o m b in a t i o n r a n ge d f r o m

 25

 to

 50

 f t - lb

(34 to

 68 ))

 at - 5 0  F

 ( -46

 C ). In al l cases

e i t her

  one or the

  o t h e r c o n s u m a b le

c o m b in a t i o n p r o d u c e d b e t t e r r e s u l t s

than did the 44 /851 .

W e ld - m e t a l t o u gh n e s s u s in g

 120/

0091 decreased w i th   C.

 For all

 C levels ,

t he re la t ionsh ip be tween toughness

and  the  m ic r o a l l o y i n g e le m e n t s was

s im i l a r : m a x im u m t o u gh n e s s o c c u r r e d

at e i ther h igh

  Cb or

  h i gh

  V,

  whereas

m in im u m t o u gh n e s s o c c u r r e d  at  h igh

Cb  +  h i gh  V  ( spec i f i ca l ly ,

  0.06%

  Cb,

0.08%

  V).

 Figures

  6 and 7

  show these

re la t ionsh ips

  for 0.08 and 0.18% C

respec t ive ly .

  CVN

  energ y us ing th is

c o m b in a t i o n v a r i e d f r o m  35 to

 95

  f t - lb

(47  to

 128

  |).

W e ld - m e t a l t o u gh n e s s u s in g TB / 1 2 1

s h o w e d

  a

  c o m p le x r e l a t i o n s h ip

  be

t w e e n

  C and the t wo

  m ic r o a l l o y i n g

e le m e n t s .

  As

 seen

  in

 Fig.

 8, all

  t o u g h

nesses at 0.08%

 C

 we r e e x c e l l e n t  ( > 90

f t - lb  [122 |] at - 5 0 F [- 46 CJ), w i t h

t o u gh n e s s im p r o v in g as Cb and V we r e

decreased.

  For

 h i gh

  C,

 h o we v e r , s u b

s tan t ia l amounts

 of V

 a n d / o r Cb , p r e f

erably  b o t h ,  are  n e e d e d  to get  go o d

we ld - m e t a l t o u gh n e s s ,

 as

 s h o w n  in Fig

9, w h ic h p resen ts  an  o p p o s i t e t r e n d

f r o m  Fig.

  8.

The fact that toughness  at

 0.18%

  C

var ies f rom  90  f t - l b  (122 J)  d o w n  to

v i r t ua l ly zero under l ines

  the

  i m p o r

tance

 of the

 m ic ro a l loy leve ls

  for

 h igh

C s i tuat ions. These resul ts indicate that

TB/121 we lds  are a f f ec ted  by  d i l u t i o n

more than we lds made wi th t rad i t iona l

iM^uM^AKC-AA€A-

fe-ii,/ '':>sV

;

-'r;:^

  r?>

  fcJfe

|pg

  A:^:^^.A--y

>

,:

l&yA-^ M

  , , f » > J

  -•••>

  •

Ar.

  •

 .yyy-yA ^Aru-;xA A '^

.- .Ay

V

' ''--*:';

 iiZ'l »\P

f

A<l

.-T:< . i . v

  ...K,, ,V. ' ' .

  »\  . \ > W

_  ' ' • • • ' . -  \ -  - • ; • * •  '

:

. . r ' -

Fig.  77—Weld-metal

  structures

 of

 steel

  132

(0.07

C,

 0.06

Cb.

 0.05

V):

  A-welded

with 44/851 (28 ft-lb

  at -50

  F); B-welded

with TB/121

 (138 It-lb at -50  F) .

 Nital etch,

X500

184-s  I |UN E

  1979

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g s u ch ti t a n i u m / b o r o n c o n s u m

W e ld - m e t a l m i c r o s t r u c t u r e s we r e

The presence o f p roeu tec to id f e r r i t e

kn ow n as ve in ing—Fig . 10A. To

to de te rm ine % ve in ing in

owe d no ve in ing—Fig . 10B.

The s t ruc tu res be tween the p roeu

Cb , 0.05% V) we ld ed w it h 4 4/851

0 F (38 and 187 J at -4 6 C) , respec

A l th ou gh the t rend fo r a wh i le had

ess that a go od w el d metal

^

  *y*

  *

3

  v v

c if*  fcSftA

y^'^y

« ^ .

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yy-:* ^*,

  •

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  .-• "%

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;

  V  

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  / , «*

  • V»  - - ? •  - 2  . J

  ;

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i .

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  V

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r

  •  ,— j

fr'  t  r

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.

  c

c

  , V  . ••. *

' • •' '-

 '

£

• ic

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  •

t

  \

Jt   •>

  ~

A-

t

  * »

  **

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v

1

  V , >•

. - . *«*v.

«r*

•  -:-

  - ™ —

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*•  y

 13—M-A  phase in two welds in steel 132

C, 0.06 Cb, 0.05 V): A-welded

  It-lb

  at -50 F); B-welded

  (138  ft-lb at -50 F). 10

sodi

metabisulfite, x  1000  (reduced 20 on

Fig.  12— Two weld metal structures pro

duced with TB/121: A-steel 312 (15 ft-lb at

-50 F); B-steel  332 (95 ft-lb at -50 F). Nital

etch,  X500

t ion is by no means that s im ple.

Gar land and K i r kwood had a lso made

a s im i la r po in t .

3

Some inves t iga to rs have cons idered

that the coarsening of ac icular fer r i te

may be a cause of poor tough ness .

Figure 12 shows two st ructures in

wh ich la th s ize may be a con t r ibu t ing

fac to r t o t oughness . However , t he

quant i tat ive analys is of la th s ize is not

pract ical for such st ructures.

Th e m a r t e n s i t e / a u s t e n i t e m ic r o c o n -

s t i t uen t kn ow n as M-A has been

repor ted to be de t r im enta l t o  w e l d -

meta l t oughness .

5

  For th is reason, we

examined we ld meta l samples to de

t e r m in e t h e a m o u n t o f M - A m ic r o -

phase present . The samples were

examined a t

  X1000

  a f t e r e t ch ing w i th

sod ium metab isu l f i t e , and the M-A

feature is d is cer nib le in Fig. 13, w hi ch

has the same weld metals as those

sho wn in F ig . 11 . As de te rm ine d by the

TAS,

 the percentag es of the M-A phase

in several welds (Table 5) point to a

re la t ion be tween th is phase and

toughness— spec i f i ca l ly , t he more M-A

the lower t he toughness .

Straight-Cb Steels

F o u r s t e el s w e r e m a d e w i t h C b a s

t h e o n l y m i c r o a l l o y i n g

  e lement—Table

6 . S t r e n g t h a n d b o t h t h e b a s e m e t a l

a n d H A Z t o u g h n e s s e s w e r e m a x i m i z e d

i n t h e 0 .0 6 - 0 . 1 2 % C b r a n g e , w h e r e a s

w e l d - m e t a l t o u g h n e s s w a s be s t a t

a b o u t 0 . 0 6 % C b .

M e t a l l o g r a p h i c e x a m i n a t i o n s

s h o w e d v e r y l i t tl e d i f f e r e n c e a m o n g

t h e w e l d m e t a l a n d H A Z m i c r o s t r u c

t u r e s o f l o w - c a r b o n

  s t ra igh t -Cb

  s tee ls

o f v a r y i n g t o u g h n e s s . A s t h e r e s u l t s

i n d i c a t e , w i t h t h e p r o p e r c o n s u m a b l e s

a n d w e l d i n g c o n d i t i o n s , w e l d m e t a l

t o u g h n e s s s h o u l d n o t b e a l i m i t i n g

f a c t o r e v e n i n t h e v e r y h i g h - C b

s t ee l s .

E f fec t o f Weld Coo l ing Rate on

T oug hnes s

T a b l e 7 s h o w s t h a t a d e c r e a s e i n

c o o l i n g r a te d u e to in c r e a s i n g h e a t

i n p u t g e n e r a l l y l ea d s t o p o o r e r t o u g h

n e ss i n t h e H A Z a n d w e l d m e t a l , a n

e f f e c t g e n e r a l l y n o t e d i n t h e l i t e r a t u r e .

I n t h e H A Z t h i s d e c r e a s e d t o u g h n e s s i s

a s s o c i a t e d w i t h a c o a r s e - g r a i n e d r e

g i o n t h a t is b o t h w i d e r a n d c o a r s e r , t h e

s l o w e r t h e c o o l i n g r a t e .

A l l c o a r s e - g r a i n e d H A Z a r e a s o b

s e r v e d w e r e p r e d o m i n a n t l y b a i n i t e ,

w i t h p r e s e n c e o r a b s e n c e o f m a r t e n

s i t e a n d o v e r a l l c o a r s e n e s s b e i n g t h e

m a i n d i s t i n g u i s h i n g f e a t u r e s . F o r s t e e l

2 3 1 ( 0 .1 4 % C , 0 . 0 6 % C b , 0 % V ) w e l d e d

a t 45 and 100   k j / i n .  (1 .8 and 3 .0 k ) /

m m ) , F i g . 1 4 s h o w s a ty p i c a l c o a r s e

g r a i n e d r e g i o n . A t 1 0 0  k j / i n .  (3.0 k | /

m m ) t h e s t r u c t u r e is p r e d o m i n a n t l y

u p p e r b a i n i t e , w h e r e a s a t 4 5

  k j / i n .

  (1 .8

k j / m m ) a m i x t u r e o f l o w e r b a i n i t e a n d

m a r t e n s i t e is f o r m e d .

A m i c r o s c o p i c e x a m i n a t i o n  i n d i

c a t e d t h a t t h e a m o u n t o f p r o e u t e c t o i d

f e r r i t e d i d i n c r e a s e , a l t h o u g h t h e T A S

w a s u n a b l e t o d e t e c t a s i g n i f i c a n t

i n c r e a s e i n t h e a m o u n t o f v e i n i n g o f

1 0 0  k j / i n .  ( 3 .0 k j / m m ) w e l d s as

c o m p a r e d w i t h 4 5

  k j / i n

  (1 .8

  k j / m m )

w e l d s . A l s o , t h e s t r u c t u r e b e c a m e

c o a r s e r a t s l o w e r c o o l i n g r a t e s .

T h e s e p h e n o m e n a c a n b e s e e n in

F i g u r e 1 5 , w h i c h s h o w s t h e s t r u c t u r e

o f s t ee l 151 (0 . 09 % C , 0 . 15% C b , 0% V )

w e l d m e t a l w e l d e d w i t h T B / 1 2 1 a t 4 5

a n d 1 0 0  k j / i n .  ( 1 . 8 a n d 3.0 k j / m m ) .

T ab l e  5—M-A  M i c roph as e i n We l d M e t a l as De t e rm i ned by T A S

  (%)—Comparison

  w i t h

T oug hnes s

Base

M e t a l

132

132

132

332

312

C o m p o s i t i o n ,

C

0.07

0.07

0.07

0.19

0.18

Cb

0.06

0.06

0.06

0.07

0

%

V

0.05

0.05

0.05

0.05

0.05

W e l d

c ons um ab l es

44/851

120/0091

TB/121

TB/121

T B / 121

M-A, %

11.7

11.5

6.5

5.9

13.9

C V N ,

f t - lb ( ] )

  al

- 5 0 F ( - 4 6 C )

28 (38)

53 (72)

138

  (187)

95 (129)

15  (20)

W E L D I N G R E S E A R C H S U P P L E M E N T I 1 8 5 - s

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T ab l e

  6—Properties

  o f S t ra igh t -Cb Heats

f t - l b ( | ) at -5 0 F ( - 46 C)

C o d e

121

131

141

151

' YS-yield si

Comp

C

0.08

0.08

0.08

0.09

rength; UTS-

os i t i on , %

C b

0.03

0.06

0.12

0.15

ultimate tensile

YS,

  ksi '

64.3

69.7

71.0

66.5

UTS,  k s i

72.5

76.6

77.0

74.3

slreng h; ksi x 6.895 - MP a.

Base metal

83 (112)

125 (169)

105 (142)

95 (129)

HA Z

47 (64)

59 (80)

77 (104)

70 (95)

44/851

30 (41)

102 (138)

28 (38)

32 (43)

W e l d M e t a l

120/0091

87

  (118)

96 (130)

62 (84)

29 (40)

TB/121

139

  (188)

154 (209)

62 (84)

68 (92)

Tab le

  7—CVN

  Energy as a Func t ion o f Heat I np ut

C o m p o s i t i o n , 

Code C Cb

  y

211

  0.14 0 0.00

213 0.13 0 0.10

231 0.14 0.06 0

M2 0.13 0.03 0.05

151 0.09 0.15 0

Heat input ,

k j / i n .

(kl /mm)

45 (1.8)

75 (3.0)

100 (3.9)

45 (1.8)

75 (3.0)

100 (3.9)

45 (1.8)

75 (3.0)

100 (3.9)

45 (1.8)

75 (3.0)

100 (3.9)

45 (1.8)

75 (3.0)

100 (3.9)

C o o l i n g t i m e

from 800 to 500 C,

seconds

10

25

45

10

25

45

10

25

45

10

25

45

10

25

45

f t - lb ( |) a t - 5 0 F ( -4 6 C)

W e l d M e l a l

HA Z

39 53)

29 39)

11 15)

46 62)

42 57)

29 39)

68 92)

34 46)

29 39)

60

  81)

11 15)

36 49)

90 122)

70 95)

61 83)

44/851

58 79)

32 43)

27 37)

72 98)

45

  61)

24 33)

53 72)

39 53)

31 42)

52 71)

43 58)

32 43)

21 28)

32 43)

21 28)

120/0091

86 110)

84 114)

43 58)

74 100)

88

  119)

26 35)

79 107)

77 104)

52 71)

83 113)

46 62)

73 99)

45 61)

29 39)

51 69)

TB/121

148 (201)

10 (14)

27 (37)

81

  (110)

63 (85)

91 (123)

151 (205)

77 (104)

79 (107)

108 (146)

44 (60)

59 (80)

147 (199)

68 (92)

40 (54)

&

y xA°>

  r-.yiysp*

•:.-Ah.^w-:><,

Fig.  14—HAZ  structures of steel 231  (0.14  C,

0.06 Ch, 0 V) welded at different heat

inputs: A-45 kj/in. (68  It-lb  at -50 F);

B-100  kj/in.  (29 ft-lb at -50 F). Nital etch,

X250  (reduced 33 on reproduction)

C o n c l u s i o n s

A s t u d y

  e m p l o y i n g

  m e c h a n i c a l t e st

i n g a n d m e t a l l o g r a p h y a s w e l l as st a t is

t ic a l a n a ly s is p r o d u c e d t h e f o l l o w i n g

f i n d i n g s a b o u t t h e e f f e c t s o f c o l u m

b i u m a n d v a n a d i u m o n t h e w e l d a b i l i t y

o f H S L A s te e l s w i t h c a r b o n c o n t e n t s

r a n g i n g f r o m 0 . 0 8 t o 0 . 1 8 % :

1 .

  Base Metal.  F or t h e c o n t r o l - r o l l e d

s t e e l s o f t h i s s t u d y , t e n s i l e s t r e n g t h

i n c r e a s e d w i t h i n c r e a s i n g c a r b o n a n d

v a n a d i u m . Y i e l d s t r e n g t h i n c r e a s e d

w i t h v a n a d i u m , b u t w a s n o t a f f e c t e d

b y t h e c a r b o n v a r i a t i o n . B o t h y i e l d a n d

t e n s il e s t r e n g t h i n c re a s e d w i t h c o l u m

b i u m u p t o a b o u t 0 . 05 % . T o u g h n e s s

i n c re a s e d w i t h c o l u m b i u m u p t o

a b o u t 0 . 0 6% a n d d e c r e a s e d w i t h

c a r b o n .

2.

  Heat-Affected Zone.

  C o m p a r e d

w i t h C - M n c o m p o s i t io n s , c o l u m b i u m

w i t h o u t v a n a d i u m i n c re a s e d t h e

t o u g h n e s s w h e n c a r b o n w a s l o w a n d

d e c r e a s e d it w h e n c a r b o n w a s  h i g h .

V a n a d i u m b y i ts e l f h a d l i t t l e e f f e c t o n

t o u g h n e s s w h e n c a r b o n w a s l o w b u t

i m p r o v e d i t a s t h e c a r b o n w a s

i n c r e a s e d . F or a n y g i v e n c a r b o n l e v e l ,

t o u g h n e s s w a s l o w e s t w h e n h i g h

c o l u m b i u m a n d h i g h v a n a d i u m w e r e

c o m b i n e d . T o u g h n e s s d e c r e a s e d w i t h

i n c r e a s i n g c a r b o n a n d w i t h d e c r e a s i n g

c o o l i n g r a t e .

3 .

  Weld-Metal Toughness.

  W e l d -

m e t a l t o u g h n e s s d e c r e a s e d w i t h d e

c r e a s i n g w e l d c o o l i n g r a t e .

For a l l 0 .08% C s tee ls , a 0 .03%

T i - B - 0 . 2 5 % M o e l e c t r o d e w i t h a b a si c

f l u x g a v e t h e b e s t w e l d

  m e t a l

  t o u g h -

yyy'yy

  -

  yy.'-yyytAyAA

Fig.

  15—Weld-metal

  structures of steel 151

(0.09 C, 0.15 Cb, 0 V) welded with

TB/121 at different heat inputs: A-45 kj/in.

(147 ft-lb at -50 F); B-100  kjlin.  (40 ft-lb at

-50 F). Nital etch,  X500  (reduced 33 on

reproduction)

n e ss . H o w e v e r , t h is c o m b i n a t i o n w a s

n o t e f f e c t i v e f o r

  Ihe

  h i g h e r - c a r b o n

s t e e l s t e s t e d u n l e s s t h e r e w e r e

  s i g n i f i -

186-s  I JUNE 1979

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a m o u n t s o f t h e m i c r o a l l o y i n g

m e n t s i n t h e b a s e m e t a l .

o o t h e r c o n s u m a b l e c o m b i n a

s g a v e t o u g h n e s s e s g r e a t e r t h a n 2 0

| ) a t - 5 0 F ( - 4 6 C ) i n a l l

Acknowledgments

f o r h i s h e l p w i t h t h e e x p e r i m e n

p o r t i o n o f t h is p r o g r a m . T h e e d i t o

c o m m e n t s o f B . S. M i k o f s k y a r e

g r e a t l y a p p r e c i a t e d , a s is t h e c r i t i c a l

r e v i e w o f C . F . M e i t z n e r .

References

1.

  Box, G. E. P. , and Behnken, D. W.,

Some New Three Leve l Des igns fo r t he

S t udy o f Q uan t i t a t i v e V a r i ab l es , Techno-

metrics  2  (1960), pp. 455-475.

2.  Hart , Peter H. M. ,  et al.,  T h e W e l d

ab i l i t y o f M i c roa l l oy ed S t ee l s ,

Microalloy

ing 75 Proceedings,

  Un i on Ca rb i de , 1977 ,

pp .  540-551.

3. Cana d ian Cent re fo r M in era l and Ener

g y T ec hn o l og y , S em i na r H A Z T o ug hnes s

o f W e l d e d l o i n t s i n M i c r o a l l o y S t e e l , O t t a

w a ,

  N ove mb er 16, 1978.

4.

  Gar land, | . G. , and K i rkwood, P . R. ,

T o w a r d I m p r o v e d S u b m e r g e d A r c W e l d

M e t a l ,

Metal Construction

  7(5) , Ma y 1975,

pp. 275-283 and 7(6), June 1975, pp. 320-

330.

5. Lev in e, E. , and   H i l l ,  D. C , A Rev iew o f

the S t ruc ture and Proper t ies o f Welds in

C o l u m b i u m o r V a n a d i u m C o n t a i n i n g H i g h

S t reng t h Low- A l l oy S t ee l s , WRC B u l l e t i n

No. 213, February 1976.

(Continued from page 178-s)

E. B E TZ A N D H . K . LE U N G

v a r y n e a r l y l i n e a r l y w i t h t h e

o f h y d r o g e n i n p u t , b u t t h e

s i o n r a te is q u i t e u n r e s p o n s i v e t o

T h e e f f e c t o f p r e h e a t i n g o n

  d i f f u

a l s o b e e n i n v e s t i g a t e d . T h e

h a v e i n d i c a t e d t h a t h i g h e r

t e m p e r a t u r e , e s p e c i a l l y a b o v e

C (4 4 6 F ) , w o u l d a c c e l e r a t e t h e

r o g e n d i f f u s i o n r a t e , a n d i n c o n s e

n c e , t h e m a x i m u m v a lu e s w o u l d

e d a n d a m o r e e v e n d i s t r i b u

s o b t a i n e d .

A n o t h e r a s p e c t is t h e p o s s i b i l i t y t h a t

r o s t a t i c p r e s s u r e g e n e r a t e d b y t h e

d r o g e n a l o n e c o u l d i n i t i a t e a t e a r.

u n l i k e l y . A l l e n - B o o t h  et  a / . '

3

e s t t h a t , f o r t h i s t y p e o f f a i l u r e t o

r , t h e h y d r o s t a t i c p re s s u r e w o u l d

e d t o b e o f t h e s a m e o r d e r as t h e

t h i s c a s e is e q u i v a l e n t t o a h y d r o

p r e s s u r e c a n o n l y b e a c h i e v e d

g h a n e x c e p t i o n a l l y h i g h h y d r o

n i n p u t o f 4 0 c c / 1 0 0 d e p . m e t a l

t h e r w i t h a n e x tr a l o w f r a c t i o n a l

i d v o l u m e o f 0 .0 2 % . T h e p r o b a b i l i t y

c o m b i n a t i o n o f r a r e e v e n t s is

l o w . T h i s i m p l i e s t h a t h y d r o s t a t

I n r e g a r d t o t h e c o n t r i b u t i o n o f

g e n to t h r o u g h - t h i c k n e s s d u c t i l i

  D L „

  r e f e r e n c e is m a d e t o t h e

- s t a g e p o s s i b i l i t y t e a r i n g p r o c e s s .

t s s h o w t h a t h y d r o g e n c o n t r i b

f a i l u r e as s u b s t a n t i a l h y d r o g e n

n t e n t h a s n o t y e t d i f f u s e d t o t h e

s u s c e p t i b l e r e g i o n . B u t a t t h e l a t e r

s t a g e f a i l u r e p o s s i b i l i t y , it is f o u n d t h a t

t h e f o l l o w i n g t h r e e f a c t o r s b e c o m e

r e l e v a n t , n a m e l y , t h r o u g h - t h i c k n e s s

d u c t i l i t y , b o u n d a r y r e s t r a in t s , a n d h y

d r o g e n e m b r i t t l e m e n t , w h i c h b e a r

e q u a l r e s p o n s i b i l i t i e s i n t h e l o s s o f

d u c t i l i t y . F r o m t h i s a n a l y s i s , it is

c o n c l u d e d t h a t h y d r o g e n c a n o n l y

p l a y a s u p p o r t i n g r o l e i n la m e l l a r t e a r

i n g .

C o n c l u s i o n

A m a t h e m a t i c a l m o d e l is g i v e n

w h i c h e n a b l e s t h e i n t e r a c t i o n b e

t w e e n te m p e r a t u r e , h y d r o g e n d i f f u

s i o n a n d s t r e s s - s t r a i n l e v e l s t o b e

  s t u d

i e d q u a n t i t a t i v e l y , f o r t y p i c a l w e l d e d -

j o i n t s , w h e n t h e jo i n t is b e i n g w e l d e d .

T h r o u g h v a r y i n g t h e r e l a t e d p a r a m e

t e r s ,

  t h e s i g n i f i c a n c e o f h y d r o g e n h a s

b e e n r e v e a l e d i n t h e c r a c k i n g p r o c e s s

o f l a m e l l a r t e a r i n g , a n d i t w a s s h o w n

t h a t t h e h y d r o g e n e f f e c t , i n t h e f o r m

o f h y d r o s t a t i c p r e s s u r e o r d u c t i l i t y

l o s s , c a n n o t o n i t s o w n i n i t i a t e a t e a r .

T h u s it is c o n c l u d e d t h a t , i n l a m e l l a r

t e a r i n g , h y d r o g e n is n o t t h e p r i m e

f a c t o r c a u s i n g f a i l u r e , b u t p l a y s a

s u p p o r t i n g r o l e o n l y .

References

1.

  Kuma r , Ra jend ra , Phys ica l Me ta l lu rgy

of I ron and S tee l , As ia Pub l i sh in g H ouse ,

1968.

2.

  Ha l l ,

  E.O. ,  Yield Point Phenomena in

Metals and Alloys,  M a c M i l l an Co L t d . ,

1970.

3 . S t. l oh n , C , and G e rbe r i c h , W . W. ,

T he E f f ec t o f Load i ng M o de o f Hy d ro g en

E m b r i t t l e m e n t , Metallurgical Transactions,

4,   Feb. 1973, p. 589-594.

4.

  W a t a n a b e , M . , T h e  Pull-Out  T y pe

Fracture in Ro l led Steel P lates , Proc. of a

S y m pos i um on We l d i ng i n S h i p B u i l d i ng ,

Lon do n, 30 th Oc t . t o 3rd No v . 1961, The

Weld ing Ins t i t u te , 1962, pp . 219-225.

5 . He wi t t , ) ., Hy dro gen in S tee l ,  ISI

Spec ia l Repor t 73 , London, 1962, p . 83-89.

6 . N ic ho l l s , D.M . , An Inves t iga t ion o f

Lamel la r Tea r ing , D.A .E . Thes is , Cra nf ie ld

Ins t i t u te o f Tec hno logy , Sept . 1966, 121

PP-

7. Bel le n, A. , Spa nraf t , | . and va n d er

Veen , J .H., S om e S tee lmake rs ' Exper ience

on Improv ing the Res is tance o f S tee l P la te

to Lamel la r Tear ing , II W  D o c .

  IX-778-72,

1972, 9 pp.

8 . N ish io , Y ., Ya ma mo to, Y ., Ka j im oto , K .

and Hi roza ne, T ., O n the Lamel la r Tear ing

i n M u l t i r u n F il le t We l ds , M i t s ub i s h i Heav y

Indus t r ies Te chn ica l R ev iew, 9 , (3 ) , 1972,

pp. 19-27.

9 . Oc h ia i , S., Yosh ina ga, S ., and K iku ta , Y .

Format ion o f S t ress

  (Strain)—Induced

  Dif

f u s i on o f Hy d rog en and i ts S o l u t i on by

C o m p u t e r - A i d e d F in i te E l e m e n t M e t h o d ,

Trans,  japan  Iron and Steel Institute, 15,

1975, pp. 503-507.

10. A l l en -B oo th , D.M . , and He w i t t , ) ., A

M a t hem a t i c a l M ode l Des c r i b i ng t he E f f ec t s

o f M i c ro - V o i ds upon t he D i f f us i on o f

Hy d rog en i n

  Iron

  and S t ee l , Acta Metallur-

gica, 22,  Feb. 1974, pp. 171-175.

11 .  K a u z m a n n , W . ,  Thermal Properties of

Matter,  V o l u m e  I—Kinetic  Theory o f Gases ,

W . A . B e n j a m i n ,  Inc. ,  New York , 1966, p .

74.

12 .  A l l e n - B o o t h , D . M . , A t k i n s o n , C , a n d

Bi lby ,  B .A ., A Nu me r ica l So lu t io n o f t he

D i f f us i on E qua t i on Res u l t i ng f r om t he V o i d

T heo ry o f t he T rapp i ng o f Hy d rog en i n I r on

and S tee l , Ac ta

  Metallurgica, 23,

  M a rc h

1975, pp. 371-376.

W E L D I N G R E S E A R C H S U P P L E M E N T I

  1 8 7 - s

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Now Avai lable . . .

WRC Bulletin 246

February 1979

Interpretive Report  on Dynam ic Analysis  of  Pressure Com ponents

This interpret ive repor t has been prepared by the Pressure Vessel Research Commit tee, Subcommit tee on

Dynamic Ana lys is o f Pressure Components .

The intent in wr i t ing th is repor t was to summar ize, in one document , a br ief background descr ipt ion of areas of

concern to t he Subcommi t tee as we l l as in fo rmat ion cur ren t ly ava i lab le t o indus t r y and to ass is t in de te rm in ing

the course of research th is Subcommit tee wi l l under take in the future.

The Subcommi t tee in deve lop ing th is repor t has assoc ia ted the cur ren t t op ics w i th t he Subcommi t tee Task

Group assignments. Each topic has been wr i t ten so that i t can be read in i ts ent i rety wi thout having cross

references to other topics. This was done for c lar i ty and to develop a procedure for inc lus ion of future work of the

Pressure Vesse l Research Commi t tee . Subcommi t tee on Dynamic Ana lys is o f Pressure Components .

Publ icat ion of th is bul let in was sponsored by the Pressure Vessel Research Commit tee of the Welding Research

Counci l .

The pr ice of WRC Bul let in 246 is $10.00 per copy. Orders should be sent wi th payment to the Welding Research

Cou nci l , 345 East 47 th St . , New York, NY 100 17.

A l s o

  R e c e n t . .

Weldability  of Steels

Third Edition

by the Welding Research Council

The th ird edi t ion of the book  Weldability of Steels  was pub l ished to update t he in fo rmat ion and make the book

avai lable again.

Specia l credi t is g iven to Messrs. C. W. Ot t and D. J . Snyder of the

  U.

  S. Steel Corporat ion for updat ing the

appe ndix tha t con tains the table Steel Co mp osi t ion s with Suggested Pract ices General ly Required for Sound

We ld ing and the Index o f S tee ls in t he Weldab i l i t y Tab le . Th is in fo rma t ion shou ld be o f va lue to a l l eng ineers

concerned wi th we ld ing .

The pr ice of th is book is $18.00. Orders should be sent wi th payment to the Welding Research Counci l ,   345

East 47th St . , New York, NY

  10017.

WRC

  Bulletin 242

October 1978

Fatigue Behavior  of  5 0 0 0 Series Aluminum Alloy Weldm ents  in  Marine

Environm ent

by W. W. Sanders, Jr. and K. A. McDowell

The repor t represen ts t he resu l t s o f a s tudy o f t he fa t igue behav io r o f 5000 ser ies a lum inum a l loy we ldments

submerged in seawater . Tes ts were conduc ted on p la in p la te , t r ansverse bu t t -we lded and long i t ud ina l bu t t -we lded

spec imens o f 5086-H116, 5456-H11G and 5456-H117 a lum inum a l loys .

Sup plem ental tests were cond ucte d, inc lud ing fat ig ue tests of s ix p la in p late spe cimen s of ABS Class C Steel .

Studies a lso inc lude the measurement of weld angles at the point of crack in i t ia t ion in welded specimens, f in i te

element analys is of a typical but t -welded shape, d is t r ibut ion of res idual s t resses and weld qual i ty evaluat ion.

Pub l ica t ion o f t h is bu l le t in was sponsored by the A luminum Al loys Commi t tee o f t he Weld ing Research

Counci l .

The pr ice of WRC Bul let in 242 is $7.00 per copy. Orders should be sent wi th payment to the Welding Research

Counc i l .

  345 Eas t 47 th St . , Room 8 0 1 , New York , NY 10017 .