一、前言武钢大型厂1986年1～2月份生产的38kg/m U_(71)Mn钢轨,在1200矫直机矫直过程中,先后两次被矫断403支。此批钢轨进入矫直机之前没有发现有不符合矫直工艺的缺陷(如严重的弯曲、扭曲、规格过大等),且凡矫断的钢轨均有结疤和裂纹缺陷。因此,现场检查人员判断此批钢轨矫断的原因为结疤缺陷 I. INTRODUCTION 38kg / m U_ (71) Mn rail produced by WISCO large-sized factory from January to February of 1986 was repeatedly straightened 403 pieces twice during straightening process of 1200 straightening machine. Before this batch of rails into the straightener did not find any flaws that do not meet the straightening process (such as severe bending, twisting, excessive size, etc.), and where the rails are scarred and cracked defects. Therefore, the on-site inspector to determine the reason for the correction of this batch of rail scarring defects