65Mn热轧带钢开裂缺陷分析及控制

Analysis and control of cracking defects of 65Mn hot rolled strip

针对65Mn热轧带钢在生产过程中出现的开裂缺陷,从成分分析、检测、原理、试验几个完整的方面进行研究,主要包括化学成分检验、金相分析、开裂断口扫描、显微硬度检测及轧后冷却方式试验对比。结果表明,马氏体相变产生的内应力超过了带钢的抗拉强度是导致65Mn带钢表面开裂的主要原因。针对该问题,通过增加侧喷吹扫能力、提高层冷冷却均匀性、避免堆冷轧后冷却工艺等措施,避免了带钢发生局部过冷及马氏体相变,解决了65Mn热轧带钢的开裂缺陷,满足了下游用户的应用需求。

For the cracking defects of 65Mn hot rolled strip in the production process, the researches were carried out from the aspects of composition analysis, detection, principle and experiment, mainly including chemical composition inspection, metallographic analysis, crack fracture scanning, micro-hardness test and experimental comparison of cooling methods after rolling. The results showed that cracking defects were caused by the internal stress produced by martensitic transformation, which exceeded the tensile strength of the steel strip. Aiming at this problem, through increasing the ability of side spraying, improving the cooling uniformity of the layer and avoiding stack cooling process, the local supercooling and martensitic transformation were avoided. the cracking defects of 65Mn hot rolled strip were solved and make the quality of 65Mn meet the application requirements of downstream users.