电弧超声激励频率对MGH956合金TIG焊接头的影响

摘要

为减少MGH956合金熔焊焊缝内的气孔量，利用高频调制TIG电弧激发超声电弧作用于MGH956合金的焊接，通过对比不同激励频率对焊缝气孔及性能的影响，分析了电弧超声激励频率对焊缝气孔及性能的作用机制及影响规律。运用理论计算的方法对焊缝中气孔的运动进行数学分析，理论计算结果与试验结果相一致。控制激励电流在15 A的条件下，激励频率为30 kHz时，焊缝的气孔量最少，且焊接接头强度达到最高，为521 MPa，达到母材的72％。实现了焊接接头断裂方式由脆性断裂转化为韧-脆混合断裂方式。%To reduce the porosity of MGH956 alloy in the weld, the arc-ultrasonic excited by modulating TIG arc through high frequency was applied in MGH956 alloy gas tungsten arc welding. The action mechanism and functionary mechanism of arc-ultrasonic on pores and tensile strength of the joints of MGH956 alloy in TIG welding was studied by introducing arc-ultrasonic at different excitation frequency. The movement of the porosity in the weld was analyzed by mathematical theory, the calculation conclusion is consistent with the experimental result that when the excitation current is 15 A, the excitation frequency decreases at 30 kHz, the number of pores is least and the tensile strength reaches the maximum as 521 MPa, reaching to 76% of the tensile strength of base metal, and the fracture mode of the joint changes from completely brittle fracture to brittle-ductile mixed fracture.