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

摘要: 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.

Abstract: The arc-ultrasonic can be excited by modulating the TIG arc through high frequency.The mechanism of arcultrasonic 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 brittleductile features.