万向轴是内燃机车传递牵引力的重要部件,主体通常由花键轴、叉头和连接管组焊而成(图1)。焊接处外径180毫米,壁厚12～15毫米,材质为35CrMoA钢。过去是采用结857焊条手工电弧焊,焊前预热温度350～400℃,劳动条件差,生产效率低,质量不稳定。近几年来,改用熔化极脉冲氩弧焊工艺后,实现了 Cardan shaft is an important component of the transmission of traction locomotives, the main body is usually splined shaft, fork head and connecting pipe welding (Figure 1). Welding diameter 180 mm, wall thickness of 12 to 15 mm, made of 35CrMoA steel. The past is the use of knot 857 electrode arc welding, welding preheating temperature 350 ~ 400 ℃, poor working conditions, low productivity, quality and instability. In recent years, the use of melting pulse welding process, achieved