Abstract: Low carbon steel’s temperature field of multi-pass welding is numerically modeled by element’s “birth” and “death” technique. Welding material can be deposited step by step during this modeling. Computation results are anastomotic well with experimental results. On the basis of this method, high-strength thick LY16 Al-alloy plant’s multi-pass welding is numerically modeled and its temperature field’s distribution regularities are analyzed. Bead interval’s influence to the distribution of temperature fields is studied. Maximum temperature rise during each pass of welding is calculated and plotted against the distance from the weld pad centre line. From the plot, component’s tissue and properties at different position after welding can be estimated.

Key words: Multi-pass welding, Numerical simulation, Temperature field