超声电弧激励电流对MGH956合金TIG焊缝气孔和拉伸性能的影响

Effect of arc-ultrasonic excitation current on pores and tensile properties of MGH956 alloy TIG weld

通过高频调制TIG焊电弧激发超声电弧,对MGH956合金进行TIG焊接,对比了在不同激励电流作用下焊缝的气孔数量和性能的变化,分析了超声电弧的作用机制.结果表明,与未施加超声电弧相比,在激励电流为5 A或10 A时,焊缝气孔明显长大,但数量并没有减少,在激励电流提高到20 A或30 A后,气孔数量急剧减少;超声电弧的引入,使焊接接头的抗拉强度得到提高,且在激励电流为20 A时,焊缝的抗拉强度达到最大为550 MPa,达到母材的76%,同时接头由完全的脆性断裂变成脆性-韧性混合断裂形式.

The arc-ultrasonic can be excited by modulating the TIG arc through high frequency. The mechanism of arc-ultrasonic was analyzed, and the effect of excitation current on pores and tensile strength of the MGH956 alloy joint made with TIG welding process was investigated. Without arc-ultrasonic, when the excitation current was 5 A and 10 A, pores in the weld obviously grew up, although the amount of pores kept almost the same. When the excitation current increased to 20 A and 30 A, the amount of pores decreased. With arc-ultrasonic, the tensile strength of the resultant joint was improved and reached the optimum value 550 MPa, 76% of that of base metal, when the excitation current was 20 A. The joints fractured with mixed brittle-ductile features.