Mathematical modelling of MAG arc welding as an engineering tool

A feasibility study has been conducted to determine if mathematical models call be used for the numerical simulation of MAG (Metal Active Gas) arc welding. In the present work, a three-dimensional (3-D),non-stationary thermal model for fillet welding is developed. The transient temperature distribution on the base metal is numerically analysed to estimate the molten pool size by using a finite difference model based oil the heat flow equation, and the theoretical configuration of molten pool is calculated, taking account of the balance of gravity, surface tension and arc pressure. The developed model can be applied to various welding processes such as multi-pass welding and welding with torch weaving for a fillet welding. The model is shown to be capable of predicting the head formation with undercutting or 'finger' type of penetration profile, caused by the effect of arc pressure. The model is also useful for estimating the temperature history ill the base metal.