Computer model for prediction of heat-affectedzone microstructures in multipass weldments

Abstract

The basis for a computer model for heat-affected zones (HAZs) in multipass weldments is described in terms of: (i) classical heat flow to define the weld thermal cycle appropriate to the welding conditions and component geometry; (ii) basic metallurgy which includes phase transformations, grain growth, and precipitate dissolution kinetics; and (iii) semi-empirical correlations to describe the effects of welding variables on the weld-bead dimensions. A computer program has been developed to simulate the fabrication of thick-section weldments. Basic welding-process information and material-property data are accepted and the spatial distribution of an HAZ structure is produced as a graphic display. This technique can be used to examine the effects of welding variables on an HAZ structure so that optimum conditions can be established for a given welding situation. A two-layer refinement technique for 0·5Cr-Mo-V weldments is used as an example.