The briefing covers quality of the shell pierced by the three-high piercing mill, thespecific rolling failures and countermeasures thereagainst.

简地介绍了三辊穿孔机所穿毛管的质量及该穿孔机特有的轧制故障预防措施。

Of equipment; without a motor and intended for hand operation (“a manual keypunch”; “a manual typewriter”).

对设备而言,指无马达用手操作的设备(如键穿孔机、字机)。

Piercing mill is the most important equipment on the rolling pipe line,and the frame is the nucleal component of the piercing mill.

穿孔机是轧制钢管的重设备,而机架又是穿孔机的核心组成部分。