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通过PLC控制AZ31合金钨极惰性气体保护焊(TIG)焊接工艺参数,研究了焊接电流、焊接速度和氩气流量对焊接接头力学性能、焊缝成形、显微组织和断口形貌的影响,并分析了各个焊接工艺参数的作用机理。结果表明,通过PLC控制焊接电流为175 A,焊接速度为5 mm/s,氩气流量为11 L/min时,焊接接头可以取得最佳的强度与塑性结合,焊接接头焊缝区成形良好,没有焊接气孔、夹杂等缺陷存在。随着焊接电流的增加,焊接接头的抗拉强度和屈服强度都呈现先增加后降低的趋势;随着焊接速度的增加,焊接接头的抗拉强度和屈服强度的变化幅度都不大;随着氩气流量的增加,焊接接头的抗拉强度和屈服强度呈现出波浪性的变化。焊接工艺参数对焊接接头力学性能的影响主要与焊接接头中存在较多的夹杂物和粗大的第二相有关。
The influence of welding current, welding speed and argon flow on the mechanical properties, weld formation, microstructure and fracture morphology of AZ31 alloy was studied by PLC control of TIG welding process parameters. The mechanism of each welding process parameter is analyzed. The results show that the optimum joint strength and plasticity can be obtained by controlling the welding current of 175 A, the welding speed of 5 mm / s and the argon flow rate of 11 L / min by PLC. The weld zone of the welded joint is well formed, No welding pores, inclusions and other defects exist. With the increase of welding current, the tensile strength and yield strength of the welded joint all increase at first and then decrease. With the increase of the welding speed, the tensile strength and yield strength of the welded joint do not vary greatly. With the increase of the welding current, With the increase of Ar gas flow rate, the tensile strength and yield strength of the welded joints show a wavy change. The influence of welding process parameters on the mechanical properties of welded joints is mainly related to the presence of more inclusions and coarse second phase in welded joints.