Abstract: In view of the characteristics of welding heat source, a new model named string heat source is established to improve calculation efficiency. First the line-Gauss heat source is derived from Gauss model, then the string model comes after it. In all these deductions, the same heat input powers are kept. The string model is more flexible and convenient than line-Gauss one. Typical welding processes are simulated by using all these models. The results show that by using the new model analysis time can be reduced greatly while high precision is still kept, and this method makes 3-D simulation of some products with ling welding practical. With line-Gauss source and string source the cutting process of side plate of bridge crane beam is simulated, and the results fairly coincide with real measurement.

Key words: Model of string heat source, Simulation, Welding