Numerical Simulation Research On Welding Process And Post-welding Heat Treatment Based On High Strength Steel

Welding is the processing technology that the same or dissimilar material components, by heat or pressure or both, with or without added materials, are non-detachable and connected or coating the pile on the substrate surface. The use of high-strength steel of the structure, not only save material and reduce the structural weight, but also improve the overall mechanical properties. Compared with the general chemical structural steel, the composition of the high strength steel is more complex, with higher sensitivity of welding residual stress, and in the welding process the use of specialized compound or specialized protective layer of complex alloy welding materials is required, and even preheating before welding and post-weld heat treatment is demanded to reduce the residual stress that may lead to hot crack, cold crack, and shape and size of the deviation caused by process defects such as welding deformation.Welding is a complicated physicochemical process which involves in electromagnetism, heat transferring, metal melting and freezing, phase-change welding stress and deformation and so on. Welding process is that parts of an area is quickly heated to high temperature and then rapidly cooled. With the heat source moving, the whole element's temperature sharply changes, and the material's physical properly parameters also sharply change. At the same time, there is latent heat of melt and phase-change. Therefore, the analysis of welding temperature field is typical nonlinear transient heat conduction. Heat convection dominant factors in post-welding heat treatment and post-welding heat treatment also belong to the typical nonlinear transient heat conduction problem. In previous study of welding, test method is often used, which is time-consuming during welding test and the effect is less satisfactory, while the use of numerical simulation that can simulate the welding process and post-weld heat treatment Temperature Field and stress-strain field well, have a great practical significance and economic value in the optimization of welding design and welding technology to reduce the experimental workload, improve the overall quality of welded structures comparison..In this paper, the welding process and the Temperature Field and Stress-strain field in the heat treatment after the welding is analyzed with finite element analysis software (ANSYS).The main content of the study:Analysis of two-way coupling field composed of the temperature field and stress field which is formed in welding process on the plate is conducted by direct method, we build a three-dimensional model that the different physical properties between basic welding metal and welding rod and Material nonlinearity and then simulate the welding process of welding parts opened V-groove using subsection heat; Analysis of the temperature field and stress field which is formed in welding process on T-weld is conducted by indirect method, Add load the form of treating the heat source as the producing rate of internal heat in the welding unit and utilizing gradually adding method of simulation materials in Life and death unit technology, comparatively analyze Stress fields of docking plate weld assembly before and after Post-welding heat treatment and compare the result of numerical simulation based on experimental.