Q345C中厚板探伤不合格原因分析与控制

Cause analysis and control of unqualified Q345C plate flaw detection

针对南阳汉冶特钢有限公司250 mm×1 650 mm断面连铸坯生产的Q345C钢板探伤不合现象,借助于高倍金相、电镜及能谱检测分析,得出探伤不合主要是中心锰偏析严重、硫化锰夹杂含量高所致。通过成分优化降低钢中锰元素含量、加大连铸二冷强度、降低钢水硫含量、钢板抢温下线缓冷等措施来提高钢板探伤质量。通过措施的采取,轧后钢板探伤合格率由之前98.40%提高到99.80%。

According to the flaw detection nonconformity of Q345 C steel plate produced by 250 mm×1 650 mm section continuous casting billet of Nanyang Hanye Special Steel Co., Ltd., by means of high power metallography, electron microscope and energy spectrum detection analysis, it is concluded that the flaw detection nonconformity is mainly caused by serious central manganese segregation and high manganese sulfide inclusion content. The flaw detection quality of steel plate can be improved by optimizing composition, reducing manganese content in steel, increasing secondary cooling strength of continuous casting, reducing sulfur content in molten steel, and slowly cooling steel plate during temperature snatching and offline. Through the adoption of measures, the qualified rate of flaw detection for rolled steel plates has increased from 98.40% to 99.80%.