Document 147367

Effect of Calcium and Magnesium
Treatment on Steel Weldability
Although Mg additions produced mixed results, calcium
additions to low-alloy steel laboratory heats improved
resistance to three types of welding-related cracking
BY R. K. WILSON
ABSTRACT. Rare earth metal (REM) additions to steels have been shown to
improve formability and toughness, and
also have been shown to improve resistance to welding-related cracking, y^jtcium and magnesium additions pfwiwce
effects on inclusions similar to those associated with REM treatments, specifically
the control of inclusion shape and the
formation of more refractory sulfides
than the relatively low-melting point MnS.
In this investigation calcium and magnesium were added to laboratory heats of
HY-80, a nickel-containing low alloy steel,
in the form of INCOCAL alloy 10* and
INCOMAG alloy 4 * addition alloys. A
third laboratory heat of HY-80 was used
as a control.
Three test methods were employed to
determine the effects of calcium and
magnesium on three types of weldingrelated cracking. The modified implant
test was used to evaluate hydrogeninduced (cold) cracking susceptibility, and
the Varestraint test was selected to test
hot cracking susceptibility. The slice bend
test was chosen to measure short transverse direction ductility, a property that is
related to lamellar tearing susceptibility.
Introduction
Sulfide shape control offers steelmakers a method of improving properties of
steel plate material, particularly formability and toughness. Rare earth metal (REM)
additions, in particular, have been shown
to provide these improvements (Ref. 1),
and also have been shown to improve
resistance to hydrogen-induced cracking
(Ref. 2) and lamellar tearing (Ref. 3) in
weldments. Calcium and magnesium
treatments provide sulfide shape control,
and they should similarly improve resistance to these weld-related cracking
problems. Such beneficial effects have
not been demonstrated previously.
^Trademark of the Inco family of companies.
182-s|JUNE 1982
Heat-affected zone (HAZ) hot cracking
occurs in the partial melting region of the
HAZ. In this area, the heat of welding
causes melting of some constituents, such
as manganese sulfides, at temperatures
below the equilibrium solidus temperature of the material. These liquids form
films at grain boundaries, which can promote separation of adjacent grains due
to the shrinkage stresses associated with
welding.
REM treatment has been shown to
increase the resistance of steels to HAZ
hot cracking, with the improvement
attributed to the substitution of high melting point rare earth sulfides for manganese sulfides (Ref 4). The sulfides of
calcium and magnesium also have high
melting points, and therefore their effect
on hot-cracking resistance should be similar to the effect of REM treatment.
When the effects of Mg and Ca additions on weldability are discussed, the
emphasis is usually on their adverse
effects on arc stability. Reactive elements
such as Mg and Ca can cause significant
changes in penetration of the arc in gas
tungsten-arc (GTA) welding due to their
effect upon the electrical characteristics
of the arc (Ref. 5). Ca and Mg also tend to
promote instability of the arc because
they form stable refractory oxides on the
surface of the molten weld metal that
interfere with the movement of electrons
and ions in the arc. REM elements, however, are also reactive and form stable
refractory oxides. Therefore, it is very
likely that their effects on penetration and
arc stability in GTA welding would be
similar to the effects of Mg and Ca (Ref.
6). These effects will probably limit the
use of Ca, M g or REM additions in, for
Based on paper presented at the AIME Fall
Meeting held in Milwaukee, Wisconsin, during
September 1979.
example, austenitic stainless steels that
will be joined using automated high
speed GTA welding.
The primary reason that there is little
concern regarding adverse affects of
REM's in low-alloy steels is that the processes used to weld this class of alloys are
not significantly affected by reactive elements. Low-alloy steels are seldom
welded with the GTA process, and processes such as shielded metal-arc, gas
metal-arc, and submerged-arc welding
are much less sensitive to minor compositional variations. The important point is
that magnesium and calcium are likely to
be similar to REM's in both their beneficial
and adverse effects on weldability.
Experimental Details and Results
Material
The alloy composition selected for
these experiments was HY-80, a highstrength low-alloy steel that has been
used in past studies of REM effects. The
HY-80 alloy chemistry is given in Table 1.
Sulfur was intentionally added to give
values near its specified maximum so that
addition alloy effects would be more
likely to be evident. The nickel content
(2.0-3.5%) of HY-80 allowed introduction
of Mg and Ca into the melt using Ni-Ca
and Ni-Mg addition alloys while retaining
other composition variables essentially
constant.
Three hundred pound (136 kg) air
melts were made of three compositions,
the only difference being a late addition
of 0.05% magnesium or calcium as INCOMAG alloy 4 or INCOCAL alloy 10,
respectively.* Initial nickel contents of the
treated heats were adjusted to compensate for the nickel content of the addition
alloy, yielding a total nickel level in each
heat of 2.8%. While the addition of Mg or
Ca could be used for removal of sulfur by
R. K. WILSON is Joining Section Manager, Inco
Research & Development Center, Inc., Sterling 'Referred to as alloys 4 & 10 throughout the
Forest, Suffern, New York.
balance of this paper.
Table 1—HY-80 Specification and Results of Chemical Analysis, Wt-%
HY-80 limiting
composition',*•>
C
Mn
Si
Ni
0.18
0.10-0.40
0.15-0.35
2.00-3.25
1.00-1.80
0.20-0.60
0.025
0.025
0.02
0.03
0.25
Cr
Mo
P
S
Ti
V
Cu
Mg
Ca
Al
Fe
Untreated
Mg-treated
0.15
0.24
0.18
2.86
1.53
0.42
0.15
0.24
0.17
2.89
1.45
0.41
0.15
0.24
0.16
2.83
1.51
0.41
0.017
0.019
0.006
0.019
0.014
0.007
0.018
0.014
0.006
0.0005
0.0005
0.046
0.016
0.0005
0.040
Bal.
0.0005
0.002-0.004
0.044
Bal.
Bal.
Bal.
Ca-treated
Wr^r^^i^K-A'<7Tt^A^ti^
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(a) Single numbers indicate maximum allowable content of that element.
floating o f M g S or CaS o u t o f t h e melt,
the o b j e c t i v e o f this w o r k w a s t o e x a m ine t h e effects o f t h e elements o n sulfide
inclusions in t h e plate. T h e r e f o r e , melting
practice w a s a d j u s t e d t o retain a b o u t t h e
same level o f sulfur in all t h r e e experimental heats.
The initial charge o f Fe, N i , Cr, a n d M o
w a s m e l t e d a n d Si, M n , S, V a n d one-half
of t h e Al w e r e a d d e d at 2800°F
(1540°C). T h e t e m p e r a t u r e o f t h e melt
w a s t h e n raised t o 2950°F ( 1 6 2 0 ° C ) , a n d
it w a s transferred t o a ladle, w h e r e Ti, t h e
remaining half o f t h e AI, a n d finally t h e
a d d i t i o n alloy (if specified) w e r e a d d e d .
T h e heat w a s t h e n p o u r e d into a 7 X 7 in.
(180 X 180 m m ) ingot m o l d . T h e t h r e e
heats w e r e h o t rolled at 2050°F ( 1 1 2 0 ° C )
t o 1 in. (25.4 m m ) thick plate. T h e plates
r e c e i v e d t h e standard q u e n c h a n d t e m per heat t r e a t m e n t o f 1650°F ( 9 0 0 ° C ) / 1
h / w a t e r q u e n c h ; 1200°F ( 6 5 0 ° C ) / 1 h/air
c o o l . Tensile p r o p e r t i e s o f t h e three
heats, s h o w n in Table 2, w e r e w e l l a b o v e
t h e specified m i n i m u m values f o r HY80.
Results o f chemical analysis (Table 1)
s h o w e d that c o m p o s i t i o n s w e r e u n i f o r m
"*/*
except f o r t h e M g a n d Ca additions.
Calcium c o n t e n t f o r the t r e a t e d heat w a s
quite l o w , b u t p r e v i o u s w o r k (Ref. 7) h a d
s h o w n beneficial effects at l o w Ca levels.
Fig. 1 — Typical nonmetallic inclusions in longitudinal sections of untreated HY-80 steel. 2%
Nital etch. X1000 (reduced 50% on reproduction)
The steels w e r e e x a m i n e d metallographicaliy, a n d t h e r e w a s e v i d e n t l y inclusion shape c o n t r o l in t h e t r e a t e d heats.
Figures 1-3 s h o w longitudinal sections
perpendicular t o the plate thickness. In
Fig. 1 t h e malleable e l o n g a t e d inclusion
shape characteristic o f u n t r e a t e d steels is
s h o w n . T h e sharp points o f this t y p e o f
inclusion are particularly d e t r i m e n t a l f o r
h y d r o g e n - i n d u c e d cracking a n d lamellar
tearing resistance.
that plate inclusions are nearly circular in
cross-section, rather t h a n e l o n g a t e d in
t h e rolling d i r e c t i o n . This t y p e o f circular
cross-section is e v i d e n t in t h e calciumt r e a t e d H Y - 8 0 - F i g . 3. Despite t h e l o w
level o f calcium analyzed in t h e steel, t h e
e l e m e n t e x e r t e d a s t r o n g shape c o n t r o l
effect.
Figure 2 s h o w s typical inclusions in t h e
m a g n e s i u m - t r e a t e d plate. S o m e e l o n g a t e d inclusions are e v i d e n t , b u t t h e
inclusions a r e m o r e r o u n d e d a n d m a n y o f
the particles are nearly circular in cross
section.
T h e elements used f o r shape c o n t r o l
c o m b i n e w i t h o x y g e n a n d sulfur at high
t e m p e r a t u r e s . T h e resulting inclusions a r e
nearly spherical, a n d these hard particles
resist plastic d e f o r m a t i o n d u r i n g subseq u e n t hot rolling o f the ingot. T h e result is
Figures 4 a n d 5 c o n f i r m that m a g n e sium a n d calcium are associated w i t h
sulfur in the inclusions o f t h e t r e a t e d
heats. T h e m i c r o p r o b e x-ray m i c r o g r a p h s
s h o w high c o n c e n t r a t i o n s o f sulfur a n d
either magnesium or calcium in t h e inclusions. Figure 5 is particularly interesting,
since
it s h o w s
calcium
distributed
t h r o u g h o u t t h e large, circular inclusions
w h i l e sulfur is c o n c e n t r a t e d at t h e e d g e .
This is e v i d e n c e o f t h e fact that calcium
aluminate (Ref. 8) f o r m s first in t h e c o o l -
Table 2—Tensile T est Results (Average of T w o Tests)
3.2%
yield strength
Ultimate
tensile streng th
psi
(MPa)
Elongation,
R.A.,<a>
(800)
20.5
66.25
133,900
(923)
16.5
55.0
(634)
(638)
110,700
110,700
(763)
(763)
20.5
19.0
68.25
58.75
100,700
111,650
(694)
(770)
120,300
127,600
(829)
(800)
19.5
17.5
64.25
56.25
80,000
95,000
80,000
95,000
(552)(655)
(552)(655)
104,000<b>
(717)
20
55
b)
(717)
20
50
Heat
Orientation
psi
(MPa)
Control
(untreated)
Parallel
96,500
(665)
116,150
Transverse
110,700
(763)
Mg treated
Parallel
Transverse
91,950
92,550
Ca treated
Parallel
Transverse
HY-80
specification
Longitudinal
Transverse
104,000<
(a) R.A. — reduction in area.
(b) Recorded for information.
WELDING RESEARCH SUPPLEMENT 1183-s
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Fig. 2 — Typical nonmetallic inclusions in longitudinal sections of Mg-treated HY-80 steel. 2%
Nital etch. X1000 (reduced 50% on reproduction)
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Fig 4 —Microprobe analysis of inclusions in
Mg-treated heat: A — secondary electron
image; B —x-ray scan for Mg; C —x-ray scan
for S. X1000 (reduced 38% on reproduction)
Fig. 5—Microprobe analysis of inclusions in
Ca-treated heat: A—secondary electron
image; B — x-ray scan for Ca; C — x-ray scan for
5. XI500 (reduced 38% on reproduction)
•
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strength of the steel in this direction is
exceeded, cracks occur in the plate.
These cracks can be entirely beneath the
F<g. 3 — Typical nonmetallic inclusions in longi- plate surface, so that they are invisible
tudinal sections of Ca-treated HY-80 steel. 2%
and are difficult to detect by nondestrucNital etch. A-X100; B - X500 (reduced 50%
tive testing. Inclusions are critical in lamelon reproduction)
lar tearing, because they lower the fracture strength of the steel in the short
transverse direction.
There is considerable controversy
about which test method provides the
ing melt, with the sulfide forming at lower
best correlation with lamellar tearing.
temperatures.
Welding tests are advocated, because
only they can include all factors present in
Slice Bend Testing for Lamellar Tearing
actual weldments. Nondestructive testing
is recommended, because it can evaluate
Lamellar tearing is a particularly insidithe inclusion content of the particular
ous type of weld cracking that occurs in
area of the plate that is to be welded, and
welded steel construction. In certain
local variations can be important in lameltypes of weld joints, the residual stresses
lar tearing.
of welding are imposed across the
through-thickness (short transverse) diProbably the most widely accepted
rection of the plate. When the fracture
method of testing is to measure the
184-s | JUNE 1982
ductility of the plate in the short transverse direction. Low ductility in this direction is generally agreed to be an indicator
of lamellar tearing susceptibility (Ref. 9,
10), although definitive correlations of
measured ductility and actual susceptibility have not been made (Ref. 11). Tearing
in a particular joint is affected by joint
design, welding variables, composition
and properties of the alloy, and by the
local inclusion content and distribution in
the joint region. For this reason, it is
probably unrealistic to expect more than
a general correlation between short
transverse direction ductility and lamellar
tearing susceptibility.
Short transverse direction tensile test
specimens are difficult to machine, and
the volume of plate that they test is
extremely small. To overcome these limitations, thp slice bend test was developed (Ref 12). This test measures bend
does indicate that the M g treated heat
would likely be less resistant to lamellar
tearing while the Ca treated heat would
be more resistant.
The test is performed by moving the
former in 0.01 in. (0.25 mm) increments
and visually inspecting the surface of the
specimen. In this work, as in the literature
(Ref. 12), the total amount of former
movement at which a single crack
extended to Vs in. (3 mm) in length or
greater was recorded for each specimen.
Figures 7 and 8 show results for six
specimens of each material in the transverse and parallel orientations. The magnesium-treated heat clearly had the lowest ductility when measured by this test,
while the calcium-treated heat was the
most ductile.
-SURFACE GROUND AT 4 5 °
TO LONGITUDINAL AXIS
Fig. 6—Schematic of slice bend test: A —
specimen removal from 1 in. (25.4 mm) thick
plate; B — specimen dimensions in inches; C —
specimen in position between former and die
block
ductility in the short transverse direction,
and results have been shown to correlate
with both through-thickness tensile test
results and lamellar tearing susceptibility.
The test, illustrated in Fig. 6, imposes
tensile stresses upon the convex portion
of the bend specimens, which can be
removed from the plate either parallel or
transverse to the rolling direction — Fig. 6.
Both orientations were used in this
work.
The results for these heats show that
magnesium treatment reduced through
thickness ductility while calcium addition
improved it. Although this is not a direct
measure of lamellar tearing resistance, it
.30
Compared to the alloys evaluated by
Drury and Jubb (Ref. 12), the untreated
and calcium-treated heats are both lamellar tearing resistant. The improvement
gained through calcium treatment is
especially encouraging, since the control
heat was relatively ductile. On the other
hand, the marked decrease in ductility of
the magnesium-treated HY-80 is a cause
for concern. The results for calcium and
magnesium treatment must be confirmed
with additional data, preferably from
larger heats, to be definitive. As for other
lamellar tearing tests, localized variations
in the quantity and morphology of inclu-
.to
•
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Fig. 7 —Slice bend test results of specimens removed transverse to the Fig. 8-Slice bend test results of specimens removed parallel to the
rolling direction
rolling direction
WELDING RESEARCH SUPPLEMENT 1185-s
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ENERGY INPUT OF EACH
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RADIUS OF FORMING BLOCK, INCHES
Fig. 9 — Varestraint test results
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sions could be significant. Such additional
testing was outside the scope of this
effort.
Varestraint Testing for Hot Cracking
Resistance
Varestraint testing was used to evaluate the effects of Mg and Ca additions on
HAZ hot cracking. The Varestraint device
(Ref. 13) imposes a controlled, variable
level of strain on a solidifying weld by
bending the test piece at a predetermined point in the weld cycle. The strain
is varied by changing the curvature of the
block around which the test specimen is
bent. After removal from the test fixture,
the total crack length of each specimen is
measured by examining the surface at
low magnification (X30).
Three specimens were tested at three
different levels of strain for each heat,
with all welds made using a standard set
of welding parameters for Varestraint
186-s | JUNE 1982
1.75
testing, i.e., 9 volts (V), 90 amperes (A), 6
ipm (2.54 mm/s) travel speed. Total crack
length for each specimen was then measured by t w o different examiners.
The data plotted in Fig. 9 show that Ca
treatment significantly reduced HAZ hot
cracking, while Mg treatment provided a
less certain improvement. Total crack
lengths were lowest for the calciumtreated heat at all three levels of strain.
For the magnesium treated steel, 2 of the
3 strain levels show somewhat lower
total crack lengths than for the untreated
heat. For the intermediate strain level,
however, the magnesium-treated heat
had a greater total crack length.
Fig. 10 —Modified implant test: A— implant
test specimen; B —notch detail; C—specimen
and plate positioned for welding (GMA weld
made along center line over specimen); D —
welded specimen placed in fixture
%j!>
1/2
WELD METAL
<WliS/MU>
j—i
\l
LOAD
Table 3—Details of Implant Test Welding and Loading
Welding:
Process
Filler metal
Parameters
Gas Metal-Arc
Linde MI-88 (90 ksi, i.e., 620.5 MPa, minimum yield strength)
Voltage
29-31 V
Current
290-31OA
Travel Speed
12 ipm (5 mm/s)
Shielding gas — Argon, 40 cfh (18.9 L/min). Hydrogen introduced by bubbling argon
through a 9 in. (22.86 cm) column of distilled water.
Loading sequence (from Ref. 14):
Time
0
Start welding
7 s
Stop welding
3 min Partially submerge specimen in ice water bath
5 min Remove from ice water and position in test apparatus
9 min Load specimen and start timer
Implant Testing for Hydrogen-Induced
Cracking
T h e m o d i f i e d implant test (Ref. 14),
s h o w n in Fig. 10, uses a helical n o t c h as
o p p o s e d t o t h e circular n o t c h of t h e
original implant test (Ref. 15). A w e l d H A Z
is c r e a t e d b y gas metal-arc ( G M A ) w e l d ing across the t o p o f the s p e c i m e n , a n d
h y d r o g e n is i n t r o d u c e d i n t o t h e w e l d m e n t b y b u b b l i n g t h e a r g o n shielding gas
through a column of water. The weldm e n t is t h e n stressed b y loading in the
implant test fixture —Table 3. Stress levels
are v a r i e d t o p r o d u c e failures in times
f r o m several minutes u p t o 24 hours (h).
In this w o r k , all samples that s u r v i v e d 3 h
of loading s u r v i v e d 24 h.
Figure 11 s h o w s a cross section of a
failed implant test s p e c i m e n . T h e f r a c t u r e
initiated in t h e H A Z just b e l o w t h e G M A
w e l d fusion line, as s h o w n in the higher
magnification m i c r o g r a p h s .
T h e test results indicate that calcium
and
magnesium
treatment
improve
h y d r o g e n - i n d u c e d cracking resistance.
T h e data f o r t h e three heats s h o w a v e r y
similar p a t t e r n in terms o f a p p l i e d stress
vs. failure t i m e (Table 4 and Figs. 1 2 - 1 4 ) .
T h e r e is a high stress region f o r each heat
w h e r e all tested specimens failed in less
than 3 h. B e l o w that region is a transition
stress w h e r e t h e probability of failure
w a s 50%. For specimens l o a d e d b e l o w
that transition stress level, n o failure
occurred.
Fig. 11 — Implant specimen: A — overall view
of cross section, X5; B and C —higher magnification views of fracture surface edges,
XI20. 2% Nital etch (A, B, and C reduced
57% on reproduction)
Table 4—Implant Test Results'*'
Untreated HY-80 Heat
Mg-treated HY-80 heat
Time to
failure,
min
psi
(MPa)
120,360
(830)
lo
106,350
(733)
54
93,830
(647)
114
48
106,350
18
108
93,830
81,320
(561)
psi
(MPa)
120,360
(830)
(733)
(647)
Ca-treated HY-80 heat
Time to
failure,
min
psi
(MPa)
66
6
120,360
(830)
3
106,350
(733)
42
12
93,830
(647)
56,300
(474)
(388)
30
NF
18
NF
87,580
NF
NF
81,320
(604)
(561)
NF
12
126
NF
3
60
3
36
12
30
18
87,580
68,810
Time to
failure,
min
(604)
18
168
81,320
(561)
NF
66
12
NF
NF
NF
75,070
68,810
(518)
(474)
NF
NF
(a) NF-no failure in 24 h.
W E L D I N G RESEARCH S U P P L E M E N T 1187-s
-Transition
\-z
Stress
^ NF(2)
lit
10
30
60
TIME TO FAILURE,
Fig. 12 — Implant test results
for untreated heat of HY80 steel
IOO
MINUTES
ik
il
Ik
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-m— Transition Stress
•>
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, r
TIME TO F A I L U R E , MINUTES
Fig. 14 - Implant test results for Ca-treated heat of HY-80 steel
Too f e w tests were run t o establish
definitely that the probability of failure at
the transition stress is 50%, or that the
probability of failure below that stress is
zero; however, the pattern was similar
for the three heats. Significantly, the transition stress level was approximately
12,500 psi (86.2 MPa) higher for the Ca
treated heat and 18,700 psi (129 MPa)
higher for the M g treated heat when
compared to the transition stress of the
untreated heat. Therefore, M g or Ca
treated HY-80 would apparently be less
susceptible to hydrogen-assisted cracking
than an untreated heat.
The trends noted would have to be
confirmed with more tests before conclusions about Mg and Ca effects could
be drawn. Because the modified implant
test fixture used in this work was built
using existing laboratory equipment, the
size of the plate into which the notched
implant test specimen was welded was
reduced from the original design used by
Sawhill, et al. (Ref. 14). This change might
have been responsible for the scatter in
the load vs. time t o failure data. Less
scatter was observed in the original work
(Ref. 14), which also used HY-80.
has provided beneficial effects on weldability analogous to those previously
demonstrated for rare earth metal additions.
The conclusions that can be drawn
from this work are:
1. Calcium treatment can improve the
resistance of HY-80 type steel to hot
cracking and probably to hydrogeninduced cracking. The Ca treatment can
also increase short transverse direction
ductility, which generally correlates with
greater lamellar tearing resistance.
2. Magnesium treatment can improve
hydrogen-induced cracking resistance
and possibly improve hot cracking resistance. Poor short transverse direction
ductility indicates that the magnesium
treated heat would likely be less resistant
to lamellar tearing than untreated HY80.
3. The fact that calcium treatment provided consistent and more significant
improvements in weld-related cracking
than treatment with magnesium is most
likely related t o the more effective inclusion shape control in the calcium treated
heat.
Conclusions
1. Luyckx, L; Bell, ). R.; McLean, A.; and
Korchynsky, M. 1970 (Dec.) Sulfide shape
control in high strength low-alloy steels. Metallurgical Transactions Vol. 1: 3341-3350.
2. Savage, W. F. 1975. The effect of rareearth additions on hydrogen-induced cracking
in HY-80 weldments. Sulfide inclusions in steel:
233-251. Metals Park, Ohio: American Society
for Metals.
References
188-s | JUNE 1982
A
A
TIME TO F A I L U R E , MINUTES
Fig. 13 - Implant test results for the Mg-treated heat of HY-80 steel
The effects of calcium and magnesium
additions on the welding-related cracking
of l o w alloy steels obviously cannot be
established from tests of one addition
level to one alloy in laboratory-size heats.
The author's objective in presenting the
data is to show that calcium, in particular,
A
A
Nf(2)
3. Farrar, j . C. M „ and Dolby, R. E. 1975.
Lamellar tearing in welded steel fabrication —
the role of sulphide inclusions. Sulfide Inclusions in Steel: 252-268. Metals Park, Ohio:
American Society for Metals.
4. Wilson, W. G. 1971. Technical note:
reduced heat-affected zone cracking and
improved base metal impacts through sulfide
control with rare earth additions. Welding
Journal 50(1): 42-s to 46-s.
5. Chase, T. F., and Savage, W. F. 1971.
Effect of anode composition on tungsten arc
characteristics. Welding Journal 50(11): 467-s
to 473-s.
6. Discussion of Weldability Effects. 1975.
Sulfide inclusions tn steels: 269-272. Metals
Park, Ohio: American Society for Metals.
7. Snape, E. Unpublished research at Inco
R&D Center.
8. deBarbadillo, ). )., (Inco R&D Center)
private communication.
9. Farrar, ), C. M.; Dolby, R. E.; and Baker,
R. C. Lamellar tearing in welded structural
steels. Welding Journal 48(7): 274-s to 282-s.
10. Holby, E., and Smith, ). F. "Lamellar
tearing —the problem nobody seems to want
to talk about", Welding Journal 59(2): 37.
11. |ubb, ). E. M. 1971 (Dec.) Lamellar
tearing. WRC bulletin no. 168.
12. Drury, M. L., and lubb, J. E. M. 1973.
Lamellar tearing and the slice bend test. Welding Journal 52(2): 88-s to 93-s.
13. Savage, W. F., and Lundin, C. D. 1965.
The Varestraint test. Welding Journal 44(10):
433-s to 442-s.
14. Sawhill, ). M.; Dix, A. W.; and Savage,
W. F. 1974. Modified implant test for studying
delayed cracking. Welding Journal 53(12): 554s to 560-s.
15. Granjon, H. 1969 (Feb.) The implant
method for studying weldability of highstrength steels. Metal Construction and British
Welding Journal.