Hot cracking in stainless steel 310s, numerical study and experimental verification

Hot cracking is a serious problem in welding of many alloys such as high strength steels, austenitic stainless steels and aluminum alloys. It takes places during the last stage of solidification where mechanical deformation develops in the mushy zone while the material has low ductility. In this study, hot cracking initiation and propagation of austenitic stainless steel 310s was studied. A viscoplastic constitutive model was proposed and implemented in finite element simulation. Solidification shrinkage, viscosity, annealing at high temperature and melting effect of fusion zone and a criterion for hot cracking initiation and propagation are the main features of the solution. Numerical results were compared with some experiments accomplished in this study in order to verify the proposed method. The results showed that maximum transverse mechanical strain criterion could predict both initiation and propagation of the hot cracking. Annealing and melting had the most effect in predicting crack length. Omission of these parameters leaded to underestimated results. Elimination of viscosity effect leaded to overestimation of the crack length while elimination of solidification shrinkage leaded to underestimated crack length.

► Hot cracking initiation and propagation of austenitic stainless steel 310s was simulated.
► Maximum transverse mechanical strain was used for the first time as the criterion for modeling crack propagation.
► The combined effect of annealing at high temperature and melting of fusion zone on crack propagation was taken into account.
► The effect of welding parameters, solidification shrinkage and viscosity on hot cracking was also studied.
► Numerical result was verified by experiments.