Abstract: Based on the situation of welding thermal conduction and thermo-elasto-plasticity research, this paper explores some problems in this field. First, the boundary element method for nonlinear problems is improved by linearization of nonlinear problems and used in welding thermal conduction analysis. Second, the thermo-elasto-plastic finite element method is used for the welding stress calculation, in which the phase transformation is considered by the "equivalent linear expansion coefficient method".The comparison of the calculated results with experimental data shows that the methods provided in this paper are available.

Key words: weld, thermal conduction, phase transformation, residual stress