无缝钢管斜轧穿孔毛管壁厚偏心分析

Analysis on wall thickness eccentricity of cross-roll pierced shells of seamless steel tube

斜轧穿孔毛管壁厚偏心是导致无缝钢管壁厚不均的重要原因,深入认识毛管壁厚偏心的特征和影响因素,是控制无缝钢管壁厚精度的必要前提。基于生产试验对无缝钢管斜轧穿孔毛管壁厚偏心进行了表征,运用解析方法建立了无缝钢管斜轧穿孔毛管壁厚偏心的计算模型,针对实际生产条件进行了预报计算和比较,研究了斜轧穿孔工艺因素对毛管壁厚偏心的影响,并分析了改善毛管壁厚偏心的方法。研究结果表明,无缝钢管斜轧穿孔毛管壁厚偏心的基本特征表现为"偏心螺旋型",在毛管壁厚不均中占比70%以上;管坯温度偏心是影响毛管壁厚偏心非常重要的因素,建议控制在10℃以内;增大斜轧穿孔变形量和毛管旋转次数有利于改善毛管壁厚偏心,相应的措施是减小送进角、增大顶头直径、减小管坯直径、增大轧辊过渡带长度;增大斜轧穿孔速度有利于改善毛管壁厚偏心。

The WTES （Wall Thickness Eccentricity of the cross-roll pierced Shell）is an important reason causing the un- even wall thickness of seamless steel tubes. A deep understanding of the characteristics and influencing factors of the WTES is the prerequisite for controlling the wall thickness accuracy of the seamless steel tubes. In this paper, the WTES of seamless steel tubes is characterized based on a series of production trials. With the calculation models of the WTES established by analytical methods, the values of the WTES are forecast and compared with the measured data pointing at actual production conditions. Based on the research of the influences of the technical factors upon the WTES, the meth- ods to improve the WTES are analyzed. The results show that the WTES can be characterized as ＂eccentric screw type＂, occupying more than 70% of the wall thickness unevenness of the shells. The temperature eccentricity of round billets is a very important factor influencing the WTES, with a proposed control range of less than 10 ~C. Increasing cross piercing deformation and the rotation times of shells is beneficial to the improvement of the WTES, and the corresponding mea- sures are to reduce the feed angle, increase plug diameter, decrease the diameter of round billet, and increase the length of the transition zone of rolls. Increasing cross piercing speed is conducive to improve the WTES.