Effects of ferrite content and microsegregation on solidification crack susceptibility of duplex stainless steel weld metals

Solidification crack susceptibility in weld metal of SUS329J2L steel of which ferrite content was varied in the range of about 0 to 100% was evaluated by Trans-Varestraint cracking test. The susceptibility was partly confirmed by self-restraint cracking test. Microsegregation of such detrimental impurities as P and S was studied in relation to the susceptibility. Main conclusions obtained are as follows: (1) Solidification crack susceptibility was minimum at ferrite level from 5 to 20%, and high not only near full austenite region but also in the level more than 40% ferrite region. (2) The cause of this tendency was inferred from the dependency of the microsegregation behavior of S and P on the ferrite content. That seemed to be because the degree of such interdendritic microsegregation is enhanced in high ferrite level compared with 5 to 20% ferrite level, (3) It was shown that such microsegregation behaivor resulted in making the solidification temperature range wider.