Finite Element Simulation For Strip Surfacing Welding With Thick Plate

With the development of petrochemical industry, their equipments becomes high-parameter and large-scale. For the hydrogenation equipments under the condition of high-temperature, high pressure and corrosive media, the surfacing with band electrode is usually used for the large area bead welding of the intine.A thermal source of the surfacing with band electrode submerged arc surfacing is designed based on its principle, and a FORTRAN subroutine is compiled to implement the translation of the thermal source in the FEA code MSC. MARC. Based on the method of heat processing contacts at the bottom of heat and thick border, and to consider the temperature-dependency of the physical parameters, radiation and convection heat transfer and transformation of latent heat, a temperature field model is established. It is shown that the simulation results are in good accordance with the actual results which proved the FEA model established in this paper is correct.A thermal source of the eletro-slay surfacing is designed referring to the electroslag casting process and 'Elements Rebirth' method is adopted to implement the thermal source. Based on the method of heat processing contacts at the bottom of heat and thick border, and to consider the temperature-dependency of the physical parameters, radiation and convection heat transfer and transformation of latent heat, a temperature field model is established. It is shown that the simulation results are in good accordance with the actual results which proved the FEA model established in this paper is correct.The strip surfacing of electro-slag strip overlay welding FEA model is established, in which coupled analysis of temperature field and stress field is adopted. In the analysis, grid transition and temperature-dependency of material properties are considered. The stress and strain variation with time during the welding process and the distribution of the residual stress and strain are emphasized.Due to the large-size of the plates, large-scalar of the grid and long time of the calculation cycle, "Elements Rebirth" method is adopted. The elements are reactivated step by step according to the welding sequence. Meanwhile, the Ian-based distributed computing platform is constructed, using three computers for parallel computing, to improve the calculation speed and saving a lot of computing time.As the study shows, the submerged arc overlay welding thermal source model is applicable. The filled molten metal method is adopted to calculate the electro-slag strip overlay welding temperature field, which can simulate the heat transfer from flux material to the base matal and also gets a favorable result.For the residual stress of the electro-slag strip overlay welding, it is compression stress in the weld joint and tensile stress in other parts. The largest tensile stress 434MPa occured at the weld joint, while the largest compression stress occured at the zone of 10 mm away from the toe of weld. There is also large tensile stress at the arc starting and arc ending area. The plate is convex in welding process and concave in cooling process.