等离子超声电弧焊接MGH956合金激励频率的计算机优化

Computer Optimization of Excitation Frequency for Plasma Ultrasonic-Arc Welding of Super Alloy MGH956

根据等离子弧焊接特点,利用双椭球体热源模型,对焊接温度场进行分析并建立三维熔池模型。以0Hz时超声电弧焊接熔池为对象,在最佳空化频率范围内,通过模态分析求解一阶谐振频率,并将与之对应的熔池响应情况进行预测。最后,通过分别施加不同大小的超声电弧频率,以三组2mm厚MGH956合金板作为实验材料进行平板对接焊试验。结果显示,接头横断面熔合线计算几何尺寸与尺寸符合良好。在谐振条件下,焊缝区面积增大,组织的细化效果较好,气孔率低,同时焊缝区软化现象得到显著改善。利用计算机模拟的方法基本达到了超声电弧频率优化的目的。

With considering the characteristics of plasma arc welding and using double ellipsoid heat source model, the welding temperature field are analyzed and 3D molten pool model was established. The mode calculation of molten pool under action of 0Hz ultrasonic-arc was conducted within the optimal frequency range and the response corresponding to modal frequency was further analyzed. Finally, three groups of 2.0 mm MGH956 alloy plates with different ultrasonic-arc frequencies were welded. The results show that the predicted geometry and locus of the fusion line in the plasma ultrasonic-arc welding weld cross-section are in good conformance with the experimental measurements. When the ultrasonic-arc frequency is equal to natural frequency of molten pool, the area of welded zone increases in depth direction, the weld structure refined is optimal, the porosity is the lowest and the softening phenomenon in welded zone improves dramatically. Using this method, the purpose of optimizing the ultrasonic-arc frequency has basically achieved.