【作者】 王飞；

【导师】 乔桂英；

【作者基本信息】 燕山大学 ， 化工过程机械， 2011， 硕士

【摘要】 串列多丝埋弧自动焊作为一种高效焊接方法，广泛应用于X80高压、大口径油气输送钢管的制造中。利用数值方法对多丝埋弧焊温度场进行模拟，对焊接应力应变分析、焊接组织性能预测以及焊接工艺制定和优化等有着重要的理论和实际意义。本文即利用ANSYS有限元软件，对X80钢管单丝、三丝、四丝埋弧焊过程进行了动态模拟。在考虑了焊丝偏转的情况下，采用双椭球形热源叠加的方法，建立了多丝埋弧焊热源模型。对于双椭球形热源形状参数的选取，采用焊缝形状反演的方法，即不断调整形状参数值，最终使模拟得出了焊缝形状与实际焊接相一致。并利用ANSYS参数化语言，完成了多丝热源热流密度的计算和移动加载，在程序中仅采用标量参数而不使用数组，并在一次循环中完成，从而避免了数值存储、调用和循环语句大量使用造成的计算量增加。同时，数值模拟考虑了材料热性能参数与温度的非线性关系，以及相变潜热对温度场的影响，并以增加高温区导热系数的方法，来间接考虑电弧冲力，从而提高了模拟的准确性。经过模拟，最终获得了焊接温度场的瞬态分布情况，并提取了焊接稳态时的熔池形状和焊接粗晶区的热循环曲线。通过焊接t8/5的数值模拟结果与实测结果比较，发现模拟值与实测值相差在10%以内，证明了模拟方法是可靠的。另外，利用焊接热模拟试验获得的管线钢焊接热影响区CCT图，结合数值模拟结果，对不同的焊接工艺条件下接头组织性能预测作了初步探索。更多还原

【Abstract】 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.更多还原