X70管线钢热轧卷唇状疤块缺陷分析

Analysis of Lip-shaped Defects on the Hot Rolled Coil of X70 Pipeline Steel

用金相显微镜等手段对X70管线钢热轧卷表面唇状疤块缺陷进行分析。结果表明:唇状疤块缺陷是在热轧过程中产生的,主要与部分喷头喷水量过大造成板面局部过冷有关。喷头冲蚀严重是引起喷水量过大的主要因素。通过更换冲蚀严重的喷头,控制好冷却速度,消除了板面唇状疤块缺陷。

The lip-shaped defects on the surface of the hot rolled coil of X70 pipeline steel were analyzed by using metallographic microscope, and the results indicated that such defects were formed in the process of hot rolling, mainly caused by partial overcooling due to excessive water spray. The lip-shaped defects were eliminated by replacing severely erodent nozzles to control the cooling speed.