WELDING RESEARCH
SUPPLEMENT TO THE WELDING JOURNAL, JUNE 1991
Sponsored by the American Welding Society and the Welding Research Council
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publication for: 1) originality of the contribution: 2) technical value to the welding community; 3) prior
publication of the material being reviewed; 4) proper credit to others working in the same area; and 5)
justification of the conclusions, based on the work performed.
The names of the more than 170 individuals serving on the AWS Peer Review Panel are published
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Influence of Carbon on Mechanical
Properties and Microstructure of Weld
Metal from a High-Strength SMA Electrode
Carbon ranges are determined for optimum toughness properties
BY E. SURIAN, J. TROTTI, R. HERRERA AND L. A. de VEDIA
ABSTRACT. This work analyzes the influence of the carbon content on the tensile
strength, notch toughness and microstructure of weld deposits produced with an
AWS E10018/E11018-M-type electrode.
Both as-welded and stress-relieved conditions have been considered. All weld
metal ISO test coupons were prepared
with experimental electrodes designed to
provide different carbon levels in the weld
deposit. The range of carbon level analyzed in the present study was 0.05 to
0.12V Within this carbon range, best all
weld metal impact properties and CTOD
values were obtained with carbon contents of about 0.07 to 0.10%. This carbon
level furnished the best combination of
toughness and tensile strength both in the
as-welded and the stress-relieved conditions.
Introduction
It is a well-known fact that an increase
in the carbon content of low and medium
strength weld deposits leads to an increase in yield and tensile strength together with some reduction in ductility. At
constant grain size, the ratio between
E. SURIAN and J. TROTTI are with Conarco
Alambres Y Soldaduras S.A., Buenos Aires, Argentina. R. HERRERA is with Intema, Mar del
Plata, Argentina. L A. de VEDIA is with Fundacion Latinoamericana de Soldadura, Buenos
Aires, Argentina.
Paper presented at the 71st Annual AWS
Meeting, held April 22-27, 1990, in Anaheim,
Calif.
yield strength and ultimate tensile strength
is reduced with increasing carbon content
(Ref. 1). In relation to this, the role played
by different alloying elements is fairly
complex. For instance, carbon behaves
differently if acting alone or in the presence of other elements such as manganese, silicon or oxygen (Ref. 2).
From the point of view of the influence
on the microstructure of deposited weld
metal, an increase in the carbon content
produces an increase in the amount of
acicular ferrite at the expense of grain
boundary ferrite. With reference to notch
toughness, increasing the carbon of weld
deposits results in a change in shape of the
transition Charpy V-notch curves, reducing the energy level of the upper shelf and
extending the transition temperature
range between brittle and ductile fracture
modes (Ref. 3). Work done by Evans (Ref.
3) on AWS E7018-type electrode weld
metal has shown that for the C-Mn system, the best combination of tensile and
KEY W O R D S
Mechanical Properties
SMAW
Carbon Content
Tensile Strength
Notch Toughness
Charpy V-notch Test
Weld Deposits
Microstructure
Yield Strength
Stress Relief
fracture properties is obtained with a carbon content in the weld deposit in the
range 0.07 to 0.09%.
The trend toward increasing use of
high-strength steels in welded components poses a demand on consumables in
order to achieve those same levels of
tensile strength coupled with good fracture toughness at the lowest service temperature. In order to cope with this last
requirement, the addition of Ni to the
weld deposit has become common practice. Nickel refines the microstructure and
promotes acicular ferrite formation. Nickel
in solid solution has the additional effect of
improving toughness at low temperatures, due possibly to its action on stacking fault energy of crystals (Ref. 1).
This work forms part of a research program on the effect of alloying elements on
mechanical properties and microstructure
of high-strength SMA weld deposits. The
influence of Mn has already been analyzed in a previous work (Ref. 4). In the
present work, the influence of carbon is
analyzed by considering four experimental iron powder AWS E10018/11018-Mtype covered electrodes. These electrodes were designed to deposit weld
metal with carbon contents ranging from
0.05 to 0.12% and were employed to
produce the standard all weld metal samples and production-type single-V-groove
welds necessary to carry out the study.
Experimental Procedure
All weld metal chemical compositions
corresponding to the four electrodes are
WELDING RESEARCH SUPPLEMENT 1133-s
Table 1—All Weld Metal Chemical Composition
Carbon
in Weld
(%)
0.05
0.07
0.10
0.12
:lement (%)
P
S
C
Si
Cu
Ni
0.024
0.025
0.028
0.031
0.013
0.013
0.009
0.011
0.05
0.07
0.10
0.12
0.25
0.26
0.34
0.33
0.06
0.06
0.05
0.05
1.84
1.90
1.92
1.88
Cr
Mo
Mn
V
N (ppm)
O (ppm)
0.05
0.05
0.05
0.05
0.34
0.34
0.35
0.34
1.21
1.24
1.42
1.41
0.01
0.01
0.01
0.01
143
119
87
444
365
345
329
99
Note: Sn, As. Co, Nb, Ti and Al 0 . 0 . maximum.
Table 2—Test Welding Procedure
Weld
Preparation
Electrode
Diameter
mm
Table 3—Base Metal Composition in
Production Single-V-Groove Weld
Pass
Interpass
°C
Current
A
Voltage
V
Heat
Imput
K|/mm
107
170
24
2.1
ISO 2560
1-last
Element (°_)
C
0.080.115
Mn
0.340.62
Si
0.10
p
0.0100.015
S
0.0200.028
Table 4—Charpy V-Notch Test Temperature
( C) Corresponding to 50 J
Single-V
weld 70-des
Specimens
Aswelded
Stressrelieved
Single-VGroove
Welds
As-welded
-73
-71
-63
-39
-42
-28
-13
-3
-63
-50
-40
-35
ISO 2560 Deposits
Carbon
in Weld
Backing
250
160
22
1.2
Rest
250
170
23
2.2
s h o w n in Table 1. Electrode diameter w a s
in all cases 4 m m (V32 in.) a n d the c o a t i n g
factor ( d e f i n e d as the ratio b e t w e e n the
coating o u t e r diameter and the c o r e w i r e
diameter) w a s maintained at 1.65. All w e l d
metal samples a c c o r d i n g t o ISO 2560-73
w e r e m a d e w i t h each e l e c t r o d e . Typical
w e l d i n g parameters used are s h o w n in
Table 2. W e l d i n g was p e r f o r m e d in the
flat position, and b e f o r e w e l d i n g , the
electrodes w e r e dried at 4 0 0 ° C (752°F)
f o r 9 0 minutes. The c a r b o n c o n t e n t s o f
the w e l d deposits w e r e 0.05, 0.07, 0.10
and 0.12%, respectively; the o t h e r elements r e m a i n e d nearly constant.
In o r d e r t o study the change in p r o p e r ties i n t r o d u c e d b y the use of p o s t w e l d
heat t r e a t m e n t , t w o all w e l d metal ISO
samples w e r e p r e p a r e d w i t h each elect r o d e . O n e sample of each pair w a s
maintained in the a s - w e l d e d c o n d i t i o n
w h i l e the o t h e r w a s s u b j e c t e d t o a stressrelieving t r e a t m e n t f o r 1 h at 6 2 0 G C
(1148°F). T w o subsize Minitrac tensile
specimens w e r e o b t a i n e d f r o m each test
c o u p o n in the a s - w e l d e d a n d stress-relieved c o n d i t i o n s and tested at r o o m t e m p e r a t u r e . Standard C h a r p y V - n o t c h specimens w e r e also m a c h i n e d o u t of the ISO
all w e l d metal samples a n d tested at t e m peratures b e t w e e n —100° a n d 2 0 ° C
( - 1 4 8 ° a n d 68°F) in b o t h t h e a s - w e l d e d
134-s|)UNE
1991
and stress-relieved c o n d i t i o n s .
T o take into a c c o u n t any possible effect
of dilution a n d / o r d y n a m i c strain aging at
the r o o t r e g i o n o n f r a c t u r e toughness o f
the w e l d deposits (Ref. 5), p r o d u c t i o n t y p e s i n g l e - V - g r o o v e multipass w e l d s
w e r e m a d e o n 1 9 - m m (V-t-in.) thick plate
w i t h each e l e c t r o d e . Typical w e l d i n g parameters used in this case are also s h o w n
in Table 2 a n d the chemical c o m p o s i t i o n
of the base plate used is s h o w n in Table
3. W e l d i n g w a s d o n e in the flat position
and t h e s e q u e n c e was such that a backing
pass w a s d e p o s i t e d first a n d , after g r i n d ing t o s o u n d w e l d metal f r o m the o t h e r
side, t h e w e l d was c o m p l e t e d . The test
panels w e r e c l a m p e d t o p r e v e n t angular
distortion d u r i n g w e l d i n g . Fracture t o u g h ness o f t h e a s - w e l d e d p r o d u c t i o n - t y p e
single-V-groove w e l d s w a s assessed b y
means of C T O D testing. For this p u r p o s e ,
full-thickness single-edge-notched t h r e e p o i n t b e n d specimens w e r e e x t r a c t e d
f r o m each w e l d , w i t h the n o t c h in the
through-thickness d i r e c t i o n as indicated
b y Fig. 1. A n initiating fatigue precrack,
w i t h initial crack d e p t h t o w i d t h ratio of
a / W = 0.5, w a s used in all cases. In o r d e r
t o p r o m o t e plain strain c o n d i t i o n s at the
crack tip, 2 5 % side g r o o v i n g o f the specimens w a s a d o p t e d . Testing w a s c o n d u c t e d at - 1 0 ° C (14°F) a c c o r d i n g t o BS
(%)
0.05
0.07
0.10
0.12
5762:79 (Ref. 6). Standard C h a r p y V n o t c h specimens n o t c h e d in the t h r o u g h thickness d i r e c t i o n w e r e also o b t a i n e d
f r o m the r o o t region of the p r o d u c t i o n t y p e single-V-groove w e l d s and tested
b e t w e e n - 6 0 ° and 100°C ( - 7 6 ° and
212°F).
A metallographic study a n d a hardness
survey w e r e carried o u t o n a cross-section
of each o f the all w e l d metal ISO test c o u pons. T h e metallographic study w a s c o n d u c t e d using light m i c r o s c o p y o n the t o p
b e a d , the grain-coarsened and grain-ref i n e d regions of the w e l d m e t a l , and along
a line coincident w i t h t h e location of the
n o t c h of t h e C h a r p y V - n o t c h samples.
C a r b o n e x t r a c t i o n replicas f o r e l e c t r o n
m i c r o s c o p y w e r e also p r e p a r e d .
Results and Discussion
As it can be seen f r o m Table 1 , c h e m ical c o m p o s i t i o n of the w e l d metal c o r r e s p o n d i n g t o the f o u r e x p e r i m e n t a l electrodes w a s fairly u n i f o r m , w i t h the e x c e p t i o n o f c a r b o n that v a r i e d b e t w e e n 0.05
and 0.12%.
T h e results c o r r e s p o n d i n g to the all
w e l d metal tensile tests in the a s - w e l d e d
and stress-relieved conditions are s h o w n
in Figs. 2 and 3. It can b e seen that yield
and tensile strength increased with the
carbon content, while elongation was reduced. As it was to be expected, stress
relieving led to some reduction in the yield
and tensile strength but did not significantly affect elongation.
Charpy V-notch curves corresponding
to the all weld metal ISO specimens in the
as-welded and stress-relieved conditions
are shown in Figs. 4 and 5. Increasing carbon content produced a shift toward
higher transition temperatures and a reduction in the upper shelf energy. Stress
relieving produced a deterioration on impact properties in the transition temperature range as judged from the 50-J transition temperatures shown in Fig. 6.
Within the carbon content range considered in this study, the best impact
properties were obtained with 0.05% C in
the weld deposit. Thus, an open question
remains concerning whether a further reduction in carbon content would still lead
to larger absorbed energy values. However, this does not seem to be relevant to
the formulation of high-strength welding
consumables because of the reduction in
tensile strength resulting from the use of
lower carbon levels than those considered in this work.
Charpy V-notch absorbed energy values corresponding to the specimens extracted from the root region of the singleV-groove welds in the as-welded condition, are shown in Fig. 7, while the
Fig. 1 — Position of
CTOD test specimen
cut from weld.
corresponding 50-J transition temperatures are indicated in Table 4. SingleV-groove weld specimens exhibited in all
cases a higher transition temperature than
the corresponding ISO specimens. This is
probably related with effects of dynamic
strain aging at the root and dilution of
weld metal with the base plate. In any
case, regardless of absolute energy values, the trend with varying carbon reproduces what was observed in the all-weld
metal specimens.
Average CTOD test results are shown
in Fig. 8. The critical event corresponded
in all cases to the first attainment of a
maximum load plateau (5m). CTOD values
were highest with 0.05% C in the weld
deposit and deteriorated with increasing
carbon content, which is in agreement
with the previous results.
Figure 9 shows the results of a hardness
ISO 2560 deposits.Aswelded
survey conducted along the central axes
of the welds' cross-sections before heat
treatment. The influence of carbon on
weld metal microstructure can be seen
from Fig. 10, which shows the results of
the quantitative assessment carried out on
the top bead of the ISO specimens in the
as-welded condition, according to the
recommendations of IIW Doc. ll-A-389-76
(Ref. 7). It is seen from Fig. 10 that increasing carbon led to a higher proportion of
acicular ferrite and to a reduction in grain
boundary ferrite. For a carbon content of
about 0.12%, a microstructure consisting
of practically 100% acicular ferrite was
obtained. Some small proportion of polygonal ferrite and ferrite with aligned MA-C was also present, but the amount of
these constituents did not seem to be significantly affected by variations in the carbon level. These results are in agreement
ISO 2560 deposits.Stress relieved
950
0,05
0,07
0,10
0,12
Carbon in weld (%)
Fig. 2 —Effect of carbon on all weld metal tensile tests (as-welded).
Carbon in weld (%)
Fig. 3 - Effect of carbon on all weld metal tensile tests (stress-relieved).
WELDING RESEARCH SUPPLEMENT 1135-s
ISO 2560 deposits.Charpy-V
ISO 2560 deposits.Charpy-V
As welded
Stress relieved
150
100cn
cn
i—
i_
0.
C
LU
OJ
c
LU
T3
TJ
CU
jQ
i_
CU
_Q
i—
O
l/l
<
o
50-
<
i
-100
I
I
-80
I
I
I—I—I—I—I—I—I—r
-60
-40
-20
0
i
-100
20
Fig. 4 —All weld metal Charpy V-notch impact test results (as-welded).
Fig. 5 —All weld metal Charpy
relieved).
w i t h p r e v i o u s findings b y Evans (Ref. 3)
that studied the influence of c a r b o n o n the
m i c r o s t r u c t u r e of C - M n w e l d deposits.
Evans f o u n d that the a m o u n t o f acicular
ferrite increased w i t h c a r b o n , w h i l e grain
b o u n d a r y ferrite d e c r e a s e d . In the w e l d
metal analyzed in the present w o r k , t h e
presence of Ni c o n t r i b u t e d f u r t h e r t o t h e
r e d u c t i o n in the p r o p o r t i o n of grain
b o u n d a r y ferrite. In this case, the c o r n -
b i n e d effect of M n a n d Ni must b e balanced t o ensure a d e q u a t e n o t c h t o u g h ness in the w e l d deposit. It has b e e n
s h o w n that the addition of Ni reduces the
o p t i m u m level of M n f r o m the p o i n t of
v i e w o f i m p a c t p r o p e r t i e s (Ref. 8). In o u r
case, w h e r e Ni c o n t e n t w a s in the range
1.85 t o 1.92%, o p t i m u m M n level w a s
f o u n d to be in the 1 t o 1.4% range (Ref.
4). M o l y b d e n u m also has an influence o n
Table 5—Primary Austenitic Grain Size in
the Columnar Region of the Top Bead (all
weld metal specimens)
Table 6—Relative Sizes of the Columnar
and Refined Regions Corresponding to the
Location of the V-Notch in the Charpy
Specimens (all weld metal specimens)
Average Columnar
Grain Width
(''.)
0.05
0.07
0.10
dim)
0.12
(a)
45
123
128
(a) It was not possible to determine this value because the
quantity of ferrite grain boundary was negligible.
136-s|JUNE
1991
Carbon
in Weld
("..)
0.05
0.07
0.10
0.12
-60
r
-2,0
-20
Test temperature l°C!
Test temperature (°C)
Carbon
in Weld
-80
Columnar
Regions
Refined
Regions'3'
(%)
40
50
30
5
(%)
60
50
70
95
(a) No distinction could be made between coarse- and finegrain refined regions.
V-notch impact
test results (stress-
w e l d metal m i c r o s t r u c t u r e . M o d e r a t e
a m o u n t s of M o (up t o a b o u t 0.5%) p r o d u c e a r e d u c t i o n in grain b o u n d a r y ferrite
w i t h a c o r r e s p o n d i n g increase in acicular
ferrite (Refs. 9, 10). Table 5 s h o w s the
variation w i t h c a r b o n of p r i m a r y austenitic
grain size in the c o l u m n a r r e g i o n of the t o p
b e a d . It w a s f o u n d that the w i d t h of the
c o l u m n a r grain increased as the c a r b o n
level w e n t u p . This finding is at first glance
c o n t r a d i c t o r y w i t h t h e observations o f
Evans a n d Taylor (Refs. 3, 8), w h o established that f o r C - M n w e l d deposits an increase in the c a r b o n c o n t e n t resulted in a
r e d u c t i o n of p r i m a r y austenitic grain size.
H o w e v e r , w h e n considering the c o m b i n e d action o f C, M n , Ni and M o , all o f
w h i c h t e n d t o suppress grain b o u n d a r y
ferrite, the results of Table 4 can be interp r e t e d (Refs. 3, 8 - 1 1 ) .
T h e relative sizes of the c o l u m n a r a n d
recrystallized regions c o r r e s p o n d i n g t o
the location of the n o t c h in the C h a r p y V n o t c h specimens, are s h o w n in Table 6.
Figure 11 s h o w s typical microstructures o f
the c o l u m n a r region of t h e w e l d metal in
Single-V joints
200
^CO05%
ISO 2560 deposits
^^-^^^cap.7%
-100
150
/
Ol
t_
OJ
0 ___As_we(ded
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/
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- •
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/
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LU
rt]
0)
/
^^"o
/
/ • • • ' "
TJ
i_
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"m
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-
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100-
in
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-50
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/
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J__
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-60
-40
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80
100
Sk,
v
1
1
0,05
1
0,07
1
1
1
0,10
1
Test
o
I
0,12
temperature(°C)
Fig. 7 - Charpy V-notch impact test results in the root of
weld specimens (as-welded).
single-V-groove
C a r b o n i n w e l d (%)
Fig. 6 - Effect of carbon on the test temperature corresponding
to 50 J.
ISQ 2560 deposits. As welded
350
%
300O
>
£ 250-
__
rD
200-
180
0,05
0,07
0,10
0,12
D i s t a n c e f r o m t o p s u r f a c e of plate(mm)
C a r b o n in w e l d ( % )
Fig. 8 —Effect of carbon on CTOD values of single-V-groove
imens (as-welded).
weld spec-
Fig. 9 —Hardness traverses along the vertical centerline. All weld metal
specimens (as-welded).
WELDING RESEARCH SUPPLEMENT 1137-s
Top central bead, I SO 2560 deposits
As welded
100
Q05
0,07
0,10
0,12
Carbon in weld (%)
| Grain boundary ferrite
Ferrite withM-A"C
Fig. tO —Effect of carbon on the microstructure
metal.
Polygonal ferrite
Acicular ferrite
of as-deposited
Fig. 11 -All weld metal specimen, as-welded, top central bead columnar zone. A -0.05% C; B-0.07"o C; C-0.10% C; D-0.12%
C.
weld
&£Z3jL. f t k « W | * ?fei
^y^NISN1&
i^^SP^
,>
i
^
l
i$SjjS$fl^lt5fc *$
^S
.Wwf
%*H
f~ $!!?&C'W'^.*^mlla*JF•'
£&$^ ^ v ^ S y ^ ^ i
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fig. 12—All weld metal specimen, as welded, grain-refined zone.
A-0.05% C; B-0.07% C; C-0.10% C; D-0.12% C
the as-welded condition, obtained with
the light microscope, for 0.05, 0.07, 0.10
and 0.12% C, while Figure 12 shows the
corresponding weld metal recrystallized
or grain-refined zones. It was observed
that within the columnar grains acicular
ferrite presented a change in the aspect
ratio with increasing carbon and evolving
138-s | JUNE 1991
toward a Widmannstatten-type of structure with precipitated carbides between
the laths (Refs. 3, 8), in particular, when
carbon content reached the 0.12% level.
In the recrystallized regions shown in Fig.
12, no distinction could be made between
coarse- and fine-grain recrystallized regions. It has been established (Refs. 3, 8)
that the action of carbon in the graincoarsened region produces the elimination of ferrite envelopes, while in the
grain-refined zone, carbon leads to a
reduction in grain size. Evans (Refs. 9, 11)
found a similar effect for Mn and M o ,
while Taylor and Evans (Ref. 8) reported a
refining action of Ni on the grain-refined
*2**«
-\<*$»
*jmM*
fig. 13-All weld metal specimen, top central bead columnar zone,
0.05",. C. A—As-welded; B — stress-relieved.
region. In order to analyze the influence of
postweld heat treatment (PWHT) on the
microstructure of the weld deposits, carbon extraction replicas from the columnar
region of the top bead were prepared for
electron microscopy. The electron micrographs corresponding to the as-welded
and stress-relieved conditions are shown
in Figs. 13 and 14 for two different carbon
levels. It was observed that the main
effect of PWHT was to reduce solute supersaturation by nucleation and growth of
carbide precipitates (Ref. 12).
Conclusions
Yield strength, tensile strength and weld
fX
^.
-* 5 s fim^
,*,#-
_jfca
Fig. l-l - All weld metal specimen, top central bead columnar zone,
0. 12% C. A -As-welded; B-stress-relieved.
metal hardness in the as-welded and stressrelieved conditions increased with carbon
content in the range analyzed (0.050.12%). The values measured after postweld heat treatment were lower than the
corresponding values in the as-welded
condition.
Charpy V-notch energy decreased with
increasing carbon content of the weld
metal in the as-welded and stress-relieved
conditions. Postweld heat treatment led
to a deterioration in the impact values as
compared to those of the as-welded condition.
CTOD values of production-type single-V-groove welds decreased with increasing carbon content, although no
change in the rupture mode from ductile
tearing to cleavage fracture was observed.
Within the carbon level range considered in this work, best combination of all
weld metal impact properties and CTOD
values were obtained with a carbon content of about 0.07 to 0.10%. Unless a requirement exists for high toughness at low
temperature (e.g., more than about 50 |
below —20°C), this carbon range furnished the best combination of toughness
and tensile strength in the as-welded and
stress-relieved conditions. If such a requirement for high toughness at low temperature does exist, then the range of 0.05
to 0.07% C should be selected.
The addition of carbon to weld metal
WELDING RESEARCH SUPPLEMENT 1139-s
produced some modifications in the microstructure. The proportion of acicular
ferrite increased, while the amount of
grain boundary ferrite was reduced. Postweld stress relieving treatment increased
the amount of carbide precipitation.
A ckno wledgments
The authors wish to acknowledge the
contribution of Dr. Ivan Hrivnak of the
Welding Research Institute of Czechoslovakia in supplying the electron micrographs, and to Mr. A. Cassanelli from INTEMA for his assistance with the experimental work.
References
1. Pickering, F.B. 1978. Physical Metallurgy
and the Design of Steels. Materials Science Se-
ries. Applied Science Publishers, London, U.K.
2. Den Ouden, C , Verhagen, |.C, and
Tichelgar, G.W. 1975. Influence of chemical
composition on mild steel weld metal notch
toughness. Welding lournal'54 (3).87-s to 94-s.
3. Evans, C N . 1981. The effect of carbon on
the microstructure and properties of C-Mn all- .
weld metal deposits. IIW Doc. ll-A-546-81.
4. Surian, E., Trotti, )., Cassanelli, A.N., and
de Vedia, L.A. 1987. Influence of Mn content on
mechanical properties and microstructure of a
high strength MMA electrode weld metal. IIW
Doc. II-A-724-87.
5. Vega, R.A., Otegui, |.L, and de Vedia, L.A.
1983. Influence of dynamic strain aging on
notch toughness of weld deposits. LatinAm. j.
of Metallurgy and Materials, 1(3):42-47.
6. British Standard Institution. Methods for
Crack Tip Opening Displacement (COD) Testing, BS 5762:79, London, England.
7. Davey, T.D., and Widgery, DJ. 1976. A
technique for the characterization of weld
metal microstructures. IIW Doc. ll-A-389-76.
8. Taylor, D.S., and Evans, C M . 1982. The
systematic development of a new range of
MMA electrodes for critical areas of offshore
fabrication. Second International Conference
on Offshore Welded Structures. The Welding
Institute, London, England.
9. Evans, C M . 1986. The effect of molybdenum on the microstructure and properties of
C-Mn all-weld metal deposits. IIW Doc. IIA-666-86.
10. ludson, P., and McKeown, D. 1982. Advances in the control of weld metal toughness.
Second International Conference on Offshore
Welded Structures. The Welding Institute, London, England.
11. Evans, C M . 1977. Effect of manganese
on the microstructure and properties of C-Mn
all-weld metal deposits. IIW Doc. II-A-432-77.
12. Evans, C M . 1984. The effect of silicon on the microstructure and properties of CMn all-weld metal deposits. IIW Doc. II-A-63084.
WRC Bulletin 358
November 1990
The Effect of Crack Depth to Specimen Width Ratio on the Elastic-Plastic Fracture
Toughness of a High-Strength Low-Strain Hardening Steel
By J. A. Smith and S. T. Rolfe
An experimental and analytical study of square three-point bend specimens was conducted to investigate the elastic-plastic fracture toughness of a high-strength low-strain hardening steel using shallow and
deep crack test specimens. Changes in CTOD level with varying crack depth-to-width ratios of CTOD
specimens were investigated for this material and c o m p a r e d to other results t o determine how material
properties, such as the strength level and strain hardening, affect the CTOD level for varying a / W ratios.
Publication of this report was sponsored by the Pressure Vessel Research Council of the Welding Research Council and the American Iron and Steel Institute. The price of WRC Bulletin 358 is $25.00 per
copy, plus $5.00 for U.S. or $ 1 0 . 0 0 for overseas postage and handling. Orders should be sent with payment to the Welding Research Council, 345 E. 4 7 t h St., Room 1 3 0 1 , New York, NY 10017.
WRC Bulletin 359
December 1990
Weldability of Low-Carbon Micro-Alloyed Steels for Marine Structures
By C. D. Lundin, T. P. S. Gill, C. Y. P. Qiao, Y. Wang and K. K. Khan
This report covers the "Validity of Carbon Equivalent Formulae," a " P r e d i c t i o n of HAZ Hardness," a
"Calculation of Cooling R a t e / C o o l i n g T i m e , " " H y d r o g e n Sensitivity and Cracking M o r p h o l o g y , " "HAZ
Softening," and presents a large number of "HAZ M i c r o s t r u c t u r e s . "
Publication of this document was sponsored by the U.S. Interagency Ship Structure C o m m i t t e e and the
Welding Research Council. The price of WRC Bulletin 359 is $45.00 per copy, plus $5.00 for U.S. or $10.00
for overseas shipping and handling. Orders should be sent with payment to the Welding Research Council, 3 4 5 E. 4 7 t h St., Room 1 3 0 1 , New York, NY 10017.
140-slJUNE 1991