15-5PH不锈钢等离子弧焊工艺优化及接头力学性能

摘要

Plasma arc welding(PAW)process was carried out to butt -weld 15-5PH stainless steel by means of univariate and orthogonal experiments.The effect of welding parameters(welding current, argon flow rate and welding speed)on welding appearance and mechanical properties of PAW joints were investigated via weld mor -phology observation and mechanical tests.It is found that both welding current and argon flow rate are of impor-tance for the weld formability and mechanical properties of the joint.With the increase of current and/or argon flow rate,the penetration of plasma arc was enhanced which resulted in defect free joints and thus better mechan -ical property.With the increase of welding speed,heat input decreased and the resultant joint was characterized with narrower weld and higher positive weld reinforcement.With the optimized parameter,i.e.,current of 220 A,argon flow rate of 3.0 L/min,welding speed of 400 mm/min,and heat input of 12.4 J/mm, a sound joint was achieved with good appearance,tensile strength of 1100MPa,impact energy of 20.5J and ductility of 8%.%采用单变量试验对15-5PH马氏体沉淀硬化不锈钢进行等离子弧焊接,通过焊缝观察及力学性能测试,研究焊接电流、氩气流量、焊接速度等工艺参数对焊缝成形及接头力学性能的影响,并通过正交试验法来优化工艺参数.结果表明:焊接电流及氩气流量与15-5PH钢的焊缝成形及接头力学性能有密切关系,适当增加焊接电流及氩气流量,有利于增强电弧穿透力、防止未焊透、避免气孔缺陷,进而改善接头综合力学性能;提高焊接速度,会导致焊接线能量下降,减小焊缝熔宽,增加正面余高.优化后的焊接工艺参数为:焊接电流220 A,氩气流量3.0 L/min,焊接速度400 mm/min,其焊缝成形良好,接头抗拉强度、冲击韧性和延伸率分别达到1100 MPa、20.5 J和8.0%.