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^ •'.-,:»,' . (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 •* *£ fNff * •••*• '..^.T^C-.X'X;, <m Fig. 2 — Typical nonmetallic inclusions in longitudinal sections of Mg-treated HY-80 steel. 2% Nital etch. X1000 (reduced 50% on reproduction) :'s : \ A- -~AAJ.\ " M • h'A\-'•'''' W-W*$ •r-^A.yy.i-rr:t<<!;.,'^i 7"|S» ^yr4&~Mm Wmm».AA^:- i 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) • Q?« 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 • - • - MAGNESIUM TREATED A - CALCIUM TREATED • • UNTREATED • .25 .25 .20 .20 - UNTREATED - MAGNESIUM TREATED - CALCIUM TREATED o < A A . 15 UJ UJ £2 • Is is Is cc o • • .1 5 .10 .10 • => o s < s s < .05 .05 AM • • 5 •z. 5 1 I 2 3 4 5 SPECIMEN NUMBER (ARBITRARY) 6 I 1 1 2 3 4 5 SPECIMEN NUMBER ( A R B I T R A R Y ) 6 I I I 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 —»J0250"F*— 300 — - UNTREATED • - - MAGNESIUM TREATED — - CALCIUM TREATED . HELICAL NOTCH-SEE DETAIL (b) 250 3 / 8 - 16 THREAD ENERGY INPUT OF EACH W E L D = 8100 JOULES PER INCH ® 200 R= .001 x O z Ul < tr o -! <. 150 100 i- o r<-.257 .250" 50 / \ T J_ 1/2 2 3 AUGMENTED STRAIN, % I 6 2.5 RADIUS OF FORMING BLOCK, INCHES Fig. 9 — Varestraint test results J_ i 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 NFI2) A -m— Transition Stress •> f , 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.
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