轨道车辆用2 mm厚X2CrNiN18-7不锈钢薄板等离子填丝对接焊工艺研究

Study on Plasma Arc Butt Welding with Filler Wire of 2 mm Thick X2CrNiN18-7 Stainless Steel Sheet for Railway Vehicle

采用等离子填丝焊工艺对轨道车辆用2 mm厚的X2Cr Ni N18-7不锈钢薄板进行对接焊接试验,通过正交试验对焊接电流、焊接速度、送丝速度和离子气流量参数进行了优化,并对最佳工艺参数下的焊接接头质量进行了焊接工艺评定。结果表明:使用Plasmatron等离子焊机成功实现了X2Cr Ni N18-7不锈钢薄板等离子填丝对接焊,优化的焊接工艺参数为焊接电流160 A,焊接速度0.25 m/min,送丝速度3.0 m/min,离子气流量5 L/min;焊缝成形良好,背面全焊透,经X射线探伤无未焊透、未熔合和裂纹等缺陷;焊接接头的综合力学性能良好,焊接接头的抗拉强度平均值为636.57 MPa,焊接接头强度系数为92.28%;180°横向正弯试验结果显示,试样正反两面均无裂纹;当疲劳测试加载循环次数为1.0×107次时,焊接接头的疲劳极限为270 MPa。

The butt weding tests of 2 mm thick X2CrNiN 18-7 stainless steel sheet for railway vehicle were carried out by using plasma arc welding with filler wire. The parameters of welding current, welding speed, wire feeding speed and ionic gas flow rate were optimized by orthogonal test, and the welding procedure qualification of the welded joint quality under the optimal welding parameters was done. The results show that the plasma butt welding with filler wire of X2CrNiN18-7 stainless steel sheet is realized by using Plasmatron plasma welding machine. The optimized plasma arc welding parameters are welding current of 160 A, welding speed of 0.25 m/rain, wire feeding speed of 3.0 m/min and ionic gas flow rate of 5 L/min. The weld appearance is good with complete penetration of weld back, and the X ray inspection results shows that there is no lack of penetration, incomplete fusion and crack defects. The overall mechanical properties of the welded joint are good. The average tensile strength of the welded joint is 636.57 MPa, and the average strength factor of the welded joint is 92.28%. The transverse bending test of 180° shows that both sides of the sample have no crack. When the loading cycle of fatigue test is 1.0×107, the fatigue limit of the welded joint is 270 MPa.