MODELLING OF ARC WELDING PROCESSES

Abstract

A review of modelling of heat transfer mechanism involved in the welding process has been done. In the beginning a brief discussion of the Rosenthal's unified theory of moving heat source for calculating the temparature transients associated with the welding process has been incorporated. Improvements of the exact solutions to relax the simplified assumptions were reviewed next. Numerical methods for solving the non—linear heat transfer equations were disc.-ssed. A mathematical model was developed to simulate the steady state, two dimensional heat flow during the fusion welding of thin plates. Arc characteristics, heat sinks, and the temparature dependance of thermal conductivity and specific heat were taken into account. The effect of liquid pool convection on the heat flow during welding was approximated with an effective thermal conductivity of the liquid phase. The results of the computer simulations were compared with the experimental thermal cycles. The observed thermal cycles widths of fusion zone and weld microstructures were compared with the calculated results of the heat flow model.