菌式穿孔顶头平整段母线和锥度

Generatrix and Taper of Smoothing Section of Piercing Point for Rotary-Rolling Mill

斜轧穿孔顶头平整段的正确设计对减轻毛管的螺旋形壁厚不均至关重要。本文通过对菌式穿孔机轧辊与轧件接触迹线的解析,导出了能与轧辊出口锥面保持均匀间隙的顶头平整段母线方程。本文还给出了锥形平整段的最佳锥角计算公式,按其设计的顶头平整段锥面在理论上可获得最佳均壁效果。本文结果同样适用于其它斜轧穿孔(即辗轧角φ=0的情形)的顶头设计。

To correctly design the smoothing section of a piercing point bar is of great impotrance to improving the evenness of shell wall. By an exhaustive analysis of the contact line between the piercing roll and working piece in rolling process on the rotary-rolling mill(or rather the mushroom type piereer), this paper has derived generatrix that can make itself form an even gap to the roll back cone of revolution, and further advanced a formular about the optimal taper β_t of piercing points smoothing section. Applying the formular on designing the piercing point, the unevenness of shell wall from a bad taper can be reduced to a minimum. The equation and the formular presented in the paper also can be used to design any piercing points of other skew roll piercing methods, which are regarded together as a special case that the oblique angle φ(not the feed angle α) is equalled by zero.