scholarly journals Investigation of Evaluation Method for Hot Cracking Susceptibility of 310S Stainless Steel during Laser Welding using Trans-Varestraint Test

2015 ◽  
Vol 33 (2) ◽  
pp. 39s-43s ◽  
Author(s):  
Dan Wang ◽  
Shuntaro Sakoda ◽  
Kota Kadoi ◽  
Kenji Shinozaki ◽  
Motomichi Yamamoto
Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3178 ◽  
Author(s):  
Wenbin Wang ◽  
Li Xiong ◽  
Dan Wang ◽  
Qin Ma ◽  
Yan Hu ◽  
...  

A new test method named “Trapezoidal hot” cracking test was developed to evaluate solidification cracking susceptibility of stainless steel during laser welding. The new test method was used to obtain the solidification cracking directly, and the solidification cracking susceptibility could be evaluated by the solidification cracking rate, defined as the ratio of the solidification cracking length to the weld bead length under certain conditions. The results show that with the increase in the solidification cracking rate, the solidification cracking susceptibility of SUS310 stainless steel was much higher than that of SUS316 and SUS304 stainless steels during laser welding (at a welding speed of 1.0 m/min) because a fully austenite structure appeared in the weld joint of the former steel, while the others were ferrite and austenitic mixed structures during solidification. Besides, with an increase in welding speed from 1.0 to 2.0 m/min during laser welding, the solidification cracking susceptibility of SUS310 stainless steel decreased slightly; however, there was a tendency towards an increase in the solidification cracking susceptibility of SUS304 stainless steel due to the decrease in the amount of ferrite under a higher cooling rate.


2008 ◽  
Author(s):  
Naoyuki Matsumoto ◽  
Yousuke Kawahito ◽  
Masami Mizutani ◽  
Seiji Katayama

2018 ◽  
Vol 941 ◽  
pp. 679-685
Author(s):  
Kazuyoshi Saida ◽  
Tomo Ogura

The hot cracking (solidification cracking) susceptibility in the weld metals of duplex stainless steels were quantitatively evaluated by Transverse-Varestraint test with gas tungsten arc welding (GTAW) and laser beam welding (LBW). Three kinds of duplex stainless steels (lean, standard and super duplex stainless steels) were used for evaluation. The solidification brittle temperature ranges (BTR) of duplex stainless steels were 58K, 60K and 76K for standard, lean and super duplex stainless steels, respectively, and were comparable to those of austenitic stainless steels with FA solidification mode. The BTRs in LBW were 10-15K lower than those in GTAW for any steels. In order to clarify the governing factors of solidification cracking in duplex stainless steels, the solidification segregation behaviours of alloying and impurity elements were numerically analysed during GTAW and LBW. Although the harmful elements to solidification cracking such as P, S and C were segregated in the residual liquid phase in any joints, the solidification segregation of P, S and C in LBW was inhibited compared with GTAW due to the rapid cooling rate in LBW. It followed that the decreased solidification cracking susceptibility of duplex stainless steels in LBW would be mainly attributed to the suppression of solidification segregation of P, S and C.


2018 ◽  
Vol 212 ◽  
pp. 54-57 ◽  
Author(s):  
Y. Zhang ◽  
D.Q. Sun ◽  
X.Y. Gu ◽  
Z.Z. Duan ◽  
H.M. Li

Author(s):  
Angshuman Chattopadhyay ◽  
Gopinath Muvvala ◽  
Vikranth Racherla ◽  
Ashish Kumar Nath

Joining of dissimilar metals and alloys has been envisioned since a long time with specific high end applications in various fields. One such combination is austenitic stainless steel grade SS304 and commercial grade titanium, which is very difficult to join under conventional fusion process due to extensive cracking and failure caused by mismatch in structural and thermal properties as well as formation of the extremely brittle and hard intermetallic compounds. One of the methods proposed in literature to control the formation of intermetallics is by fast cooling fusion process like laser beam welding. The present study has been done on laser welding of titanium and stainless steel AISI 304 to understand the interaction of these materials during laser welding at different laser power and welding speed which could yield different cooling rates. Two types of cracks were observed in the weld joint, namely longitudinal cracks and transverse cracks with respect to the weld direction. Longitudinal cracks could be completely eliminated at faster welding speeds, but transverse cracks were found little influenced by the welding speed. The thermal history, i.e. melt pool lifetime and cooling rate of the molten pool during laser welding was monitored and a relation between thermo-cycle with occurrence of cracks was established. It is inferred that the longitudinal cracks are mainly due to the formation of various brittle intermetallic phases of Fe and Ti, which could be minimized by providing relatively less melt pool lifetime at high welding speeds. The reason of the transverse cracks could be the generation of longitudinal stress in weld joint due to the large difference in the thermal expansion coefficient of steel and titanium. In order to mitigate the longitudinal stress laser welding was carried out with a novel experimental arrangement which ensured different cooling rates of these two metals during laser welding. With this the tendency of transverse cracks also could be minimized significantly.


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