| Multi-wires submerged arc welding, as an efficient welding technology, is widelyused in the manufacture of oil and gas steel pipelines with high pressure and largediameter. The welding temperature obtained by the numerical method is significant toanalysis the welding stress and strain, predict weld structure and properties, and developand optimize welding process. In this paper, the dynamic temperature fields was simulatedbased on the ANSYS software in single, three and four wires submerged arc welding.Under the condition of arc deflection, a new heat source model for SAW wasestablished, which comes from the superposition of the double ellipsoid heat source Theheat source shape parameters values were obtained by the inversion of the weld shape.That is, changing the values in order to simulate the weld seam shape consistent with theactual welding. The ANSYS Parameter Design Language (APDL) was employed forloading and calculation for the moving heat-flow density. In the calculated program, thescalar parameter instead of array was employed, which ensures the calculation completedat one cycle, and avoids the excessive computation by the array storage, recall andextensive loops. At the same time, the nonlinear relationship between material propertiesand temperature, and the latent heat was considered in the simulation, and the hightemperature thermal conductivity was increased to indirectly consider the arc momentum，which improve the accuracy of the simulation.The temperature distribution in different time was obtained by simulation, and thethermal cycling near the heat affected zone and the shape of weld pool was extracted fromthe simulation result. The results of calculation and tested t8/5error within 10%, whichshow the simulation method is correct. The prediction of joints organization andperformance under different welding processes was preliminary explored combined withthe simulation results and the weld heat affected zone CCT diagram. |
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