论文部分内容阅读
钢轨底裂是出现于轨底中央部分较大的破裂,严重时有底裂缺陷的钢轨达钢轨总产量的3.52%.本文探讨钢轨底裂的基本特征及其来源;分析影响底裂发生和扩展的主要因素;提出消除它的相应措施.试验表明,钢轨底裂来源于钢坯裂缝,而钢坯裂缝的主要根源则是钢锭横裂.钢坯有较深裂缝的一面被轧成轨底时,由于钢轨高度方向上的压缩比较小,则钢轨发生底裂的机率较大.至于在轧制中钢锭中心部分演变成为轨底时,轨底中央金属被拉伸,而在矫直时轨底受力偏大以及APl钢裂纹敏感性较大等因素影响,对裂缝的扩展也起一定的作用.消除底裂的相应措施是:加强整模操作;初轧机采用13道次轧制制度代替11道次和增加一次翻钢;钢锭窄面固定轧成轨头和轨底;改用矩形钢坯等.目前有底裂缺陷的钢轨已降低到仅占钢轨年产量的0.01%.
At the end of the rail, the bottom of the rail was found to have a large rupture, and the rail with the bottom split defect was 3.52% of the total rail. In this paper, the basic characteristics and sources of the rail rupture were discussed. The main reason for eliminating it is proposed.It is shown that the bottom of the rail is originated from the crack of the slab and the main source of the crack of the slab is the transverse crack of the ingot.When the slab with the deeper crack is rolled into the rail bottom, As the compression ratio in the height direction is smaller, the probability of occurrence of undercut of the rail is larger. As the central part of the ingot evolves into the rail bottom during rolling, the central metal at the rail bottom is stretched, Large and APl steel crack sensitivity and other factors, the expansion of the crack also play a role.Corrective measures to eliminate the end are: to strengthen the mold operation; the beginning of the mill using 13 pass rolling system instead of 11 times and Increase once rolled steel; narrow ingot fixed rolling into rail head and rail bottom; use of rectangular billet, etc .. At present, the crack with the bottom of the rail has been reduced to only 0.01% of the annual rail production.