Tests are made with three different piercing plugcone shapes to identify shell gauge changes during secondary piercing process.
采用三种不同穿轧锥形状的顶头，通过二次穿孔试验研究了毛管壁厚变化。
2
The causes on wrinkle occurrence on the working cone of piercing plug are analysed in detail, and the measures to prevent wrinkle occurrence are put forward.
详细地分析了穿孔顶头工作锥起皱的原因，提出了抑制顶头工作锥起皱的工艺措施。
3
Linear deformation zone of generating wall can be obtained by means of non-linear cone Angle plug combined with the barrel-shaped rolls, so the wall accuracy can be increased greatly.