| With the rapid development of word economy and industrial manufacture, the demand for clean energy sources (Liquefied Natural Gas, referred to as LNG) becomes more and more considerable. Domestic and foreign construction of large LNG equipment demand also increases ceaselessly subsequently. Presently, large cryogenic tanks and pressure vessels constructed the main timber is excellent cryogenic toughness of9Ni steel. Welding is the main process and link while in storage tank construction. Welding is a complicated process which involves in electromagnetism, heat transferring, metal melting and freezing, phase-change welding stress and deformation and so on. In this paper, based on a large general-purpose finite element analysis software ANSYS of domestic06Ni9steel in submerged are welding (SAW) process under the condition of dynamic welding temperature field and stress field are simulated and analyzed, the welding heat affected zone of microstructure simulation, and the simulation results and the test results were analyzed, and then verify the simulation results of accuracy.The main contents of the paper are as following:the calculation in welding process is a material nonlinear procedure that the material thermo-physical property parameters change with the temperature; choose the function of HGEN as the heat source in this simulation The heat source model can well simulate the welding process, use of APDL in the loop statement and the element birth and death technique to realize the moving heat source. Microstructure of the HAZ material were predicted by the welding cycle and SHCCT diagram of9Ni steel, prediction of the microstructure change Vickers-hardness. Experimental determination of welding HAZ of change in microstructure and Vickers-hardness, and the test results and simulation results were analyzed. Experimental study on SAW and SMAW technology of06Ni9steel cryogenic toughness, the effect of cryogenic toughness of welding joint is the main factor of welding line energy. |
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