hollow billet

• 毛管

hollow billet的用法和样例：

例句

1. It can also get the same result by raising the tube billet's heating temperature and prolonging its heating time.
   适当提高管坯加热温度和延长加热时间，均能显著减少穿孔毛管的外折缺陷，提高金属收得率。