X65级管线钢超声波探伤不合格原因分析及改进措施

Causes Analysis and Improvement Measures of Ultrasonic Flaw Detected Disqualification for X65 Grade Pipeline Steel

针对X65级管线钢超声波探伤情况进行统计,发现探伤不合格集中在370 mm厚度断面铸坯的尾坯。通过低倍、金相和扫描电镜等手段对探伤不合格的钢板作进一步分析,结果表明:铸坯内部的疏松是导致探伤不合格的主要原因。实施合理排产、优化轧制工艺等措施,使管线钢连铸尾坯探伤情况得到改善。

Statistics are made on the ultrasonic flaw detection instances of X65 grade pipeline steel,which indicates that the disqualification cases concentrates on the tail end slab of 370 mm section strand.Further analysis is performed on the disqualified steel plate in flaw detection by means of macroscopic examination,metallographic examination and scanning electron microscope.The results show that the porocity inside the strand is the major cause of the flaw detected disqualification.By taking measures of rational production scheduling and rolling process optimizing,the flaw detection result of tail end slab is improved for pipeline steel.