Monte Carlo simulation and experimental measurements of grain growth in the heat affected zone of 304 stainless steel during multipass welding

Abstract

Grain growth in the weld heat-affected zone (HAZ) of multipass welds in 304 stainless steel was studied experimentally and theoretically. A finite element heat flow model was developed and calibrated using experimental temperature data collected during multipass gas tungsten arc welding. Output from the heat flow model was used to provide temperature data as an input to a Monte Carlo (MC) HAZ grain growth model and simulation adapted to multipass welds. The grain growth, grain size, and distribution in the HAZ predicted by the MC model were consistent with metallographic measurements of grains in the HAZ. Grains near the fusion boundary grew two to three times the size of grains in the unaffected base material. The MC model was then used to investigate the influence of initial base material temperature and interpass temperature on HAZ grain growth. As initial temperature increased, the width of the fusion zone in the first pass increased and the width of and grain size in the HAZ near the first pass increased. As interpass temperature increased, the width of the fusion zone and the width of and grain size in the HAZ increases after the first pass increased.