cross roll piercing elongation mill

例句：

1. 1. The cross-roll is usedto smooth the surface of metal sheets.
   交叉滚轮用于金属板材的表面平滑。
2. 2. Thepiercing process involves cutting a hole inthe material for attachment.
   穿孔过程涉及在材料上切割一个孔以便连接。
3. 3. Elongation is the stretching of an object ormaterial.
   延伸是指物体或材料的拉伸。
4. 4. The milling machine is used to cut and shapemetal parts.
   铣床用于切割和成型金属部件。