In pressure vessels,C and D seam which are located at the joint of fla nge,tube-shape object,jointed tube,and head of pressure vessels separately are t he most complex seams.

• 压力容器设备中法兰与筒体、法兰与接管连接处的C类焊缝和封头端部、筒体上马鞍形的D类焊缝是最为不规则的且施焊工艺最为复杂的焊缝。