Application of discrete distribution point heat source model to simulate multipass weld thermal cycles in medium thick plates

Abstract

An analytical solution to the heat flow differential equation has been proposed, which allows an adequate and simplified approach to multipass welding conditions in the heat affected zone. The solution is based on the medium thick plate temperature distribution initially proposed by Rosenthal. The model applies a discrete distribution of point heat sources localised on any point of the plate that is being welded. This approach allows changing the position of the heat sources in the groove from one pass to another, reproducing multipass welding conditions. Actual thermal cycles of multipass welding of AISI 304 and 2304 stainless steels were recorded and compared with simulated thermal cycles, which verified the agreement between the simulated and the actual HAZ thermal cycles. Microstructures of alloys UNS S32304 and UNS S32205 were reproduced in the Gleeble system using the calculated thermal cycles and their comparison with actual weld microstructures confirmed the utility of the proposed heat flow model for metallurgical weldability studies involving multipass welding.