Abstract: Based on explicit analysis,a 3D FE model coupled with thermo-mechanical of radial friction lap welding joint was established with 45 steel by applying ABAQUS software.Assuming that the deformation rate is known,it is discussed the field of temperature on the welding interface and the loading force on the radial ring in the paper.Using the Johnson-cook constitutive model,thermal properties,friction coefficient changing with temperature and plastic deformation heat were also considered,The temperature field distribution and the deviation of loading pressure were predicted and analyzed.The results show that without considering the heat transfer of the radial ring and the fixture,the radial ring is formed to fixture as the center to form an elliptical temperature gradient distribution and to fixture void as the center to form an strip temperature gradient distribution.The maximum temperature reached 1 260℃ and 1 050℃.In order to simplify the welding process,the loading force curve fit for three compression process.The explicit analysis,the standards and the constitutive model were feasible.