A Study of Reheat Cracking in Weld Heat-Affected Zone of High Strength Steel

A mechanism and some factors to cause a reheat cracking in HAZ of high strength steel weldment were examined and discussed, using a T-1 type of steel. The following results were obtained in this study. (1) The reheat cracking in HAZ can be induced by both a segregation of impurities and a precipitation of carbides of secondary hardening elements at grain boundaries. In particular, the effect of a grain boundary precipitation is predominant in case of T-1 type of steel HAZ. (2) It is likely that the influence of carbides precipitated at grain boundaries on the reheat cracking susceptibility appears through a decohesion at grain boundary and a lowering of a deformability or a ductility at grain boundary because of an intense interaction between dislocations and carbides. (3) The effects of a segregation of impurities and a precipitation of carbides at grain boundary on the reheat cracking phenomenon were able to be represented schematically.