A rotary steering tool scheme was developed,and its steering mechanism was investigated intensively in this paper. 提出了一种旋转导向工具设计方案，并对其实现旋转导向的机理进行了深入研究。
Effective methods in aspects of tool design and adjusting parameters of the cross-roll piercer are put forward for improving the wall-thickness uniformity of the shell pierced. 从工具设计和轧机调整参数的角度，探讨了改善毛管壁厚均匀性的行之有效的途径和方法。
