I. Introduction
Wire rolling is a typical large deformation process and its principle is very complex, which includes material nonlinearity, geometry nonlinearity and boundary nonlinearity. It is difficult to obtain theory analytical results by trying to roll or physical experiment because they will induce many problems such as high cost, waste time and venture [1]. With the rapid advancement of computing technology and numerical method, the finite element method is regarded as the best one, which can account for the large plastic deformation, thermo-mechanical coupling and complex boundary conditions of the rollers and the billet interactions in the rolling process [2]. Rolling process involves many course parameters such as deformable speed, temperature, and stress and strain. There are heat exchange, convection and radiation phenomena, which all leads to non-uniformity change of temperature field, stress and strain field. The change of temperature also affects mechanical parameter and boundary condition. Thus, hot continuous rolling of wire belongs to thermal-mechanical coupling process. In making numerical simulation, it needs to analyze the solution of mechanical parameter and the change of temperature field together [4]. Because uneven change of stress field, rolling force and rolling torque has influence on abrasion and impact of rollers, the research of stress, mechanical parameter is useful for improvement of quality of wire and the optimization of processes parameters.