板坯角部横裂纹的控制实践

微合金化钢板坯角部横裂纹是长期困扰各大钢铁厂的难题。讨论角部横裂纹的产生机理，对角部横裂纹的工艺影响因素进行分析，并针对性地提出了控制角部横裂纹的措施。减少连铸中间包水口堵塞、控制氮含量不大于0.004 0%、关闭部分边部喷嘴、降低二冷水流量有利于控制外弧侧角部横裂纹；如果在内弧侧发现角部横裂纹，可以增加矫直段二冷水量以消除角部横裂纹。措施实施后角部横裂纹发生率由17%下降至平均4%以下。

Practice for decreasing corner transverse crack defect on slab surface

The corner transverse crack on micro-alloyed steel slab is a difficult problem that has long plagued many iron and steel plants.In this paper， the generation mechanism of cornertransverse crack is discussed， and the influencing factors of the corner transverse crack are analyzed， and the corresponding control measures are put forward.Reducingnozzle clogging in continuous casting tundish， controlling nitrogen content to be less than or equal to 0.004 0%， shutting down part of the edge nozzle and reducing secondary cooling water flow are helpful to control thecornertransverse crack on the external arc side；If thecorner transverse crack is foundin the corner of the inner arc， it can be eliminated byincreasingthesecondary cooling water of the straightening section.After the implementation of the measures， the incidence rate of cornertransverse crack is decreased from 17% to 4% or less.