热轧粗轧区擦划伤缺陷的微观特征与现场改善  

Microscopic characteristics and field improvement of scratch defects in rough rolling region

作　　者：刘学伟 LIU Xuewei(Technology Center of Baosteel Meishan Iron&Steel Co.,Ltd.,Nanjing 210039,China)

机构地区：[1]宝钢股份上海梅山钢铁有限公司技术中心,江苏南京210039

出　　处：《物理测试》2025年第1期57-62,共6页Physics Examination and Testing

摘　　要：为查找热轧精冲钢20MnB边部细线状缺陷的形成原因,提出有效的改善措施,在对热板缺陷微观组织分析的基础上,通过预制缺口+疲劳震动的方法形成显微裂纹,对带有显微裂纹的样品进行高温氧化模拟试验,研究裂纹附近组织氧化脱碳规律。结果表明,氧化圆点的深度与加热温度具有强相关性,是判断缺陷形成温度的主要依据;对比高温氧化模拟试验及热板缺陷的微观特征,认为热轧板边部缺陷在粗轧区域产生,其典型的微观特征是裂纹附近有深度小于5μm氧化圆点区,金相组织有轻微晶粒长大及脱碳或没有。根据上述结论对粗轧区设备进行检查,发现立辊表面粗糙且有粘钢,是导致细线状缺陷的主要原因,为此调整了立辊的润滑工艺与使用周期,轧制油浓度由3‰提高至5‰,大大降低了该类缺陷的发生率。In order to find out the causes of fine line-like defects at the edges of 20MnB hot rolled fine-blanking steel and propose the effective improvement measures,the micro-cracks were formed by pre-crack and fatigue vibration based on the microstructure analysis of detects in hot rolled plate.The sample with micro-cracks was used for high-temperature oxidation simulation experiments.The oxidation and decarbonization laws of microstructure near the micro-cracks were investigated.The results showed that the depth of oxidation dots was strongly correlated with heating temperature,which was the main basis for judging the formation temperature of defects.The microscopic characteristics in high-temperature oxidation simulation experiments were compared with the defects in hot rolled plate.It was considered that the edge defects in the hot rolled plates occurred in the rough rolling region.The typical microscopic characteristic was that there was an oxidation dot zone with a depth of less than 5μm near the crack,as well as the slight grain growth and decarbonization or not in metallographic structure.According to the above conclusion,the equipment in rough rolling region was checked up,and it was found that the vertical roller surface was rough and there were adhesive steels on it,which were the main reasons to cause fine line-like defects.The lubrication process and working period of the vertical roller were adjusted.The percentage of the rolled oil was increased from 3‰to 5‰.Finally,the fine line defects at the edges were significantly reduced.

关 键 词：粗轧 擦划伤 微观组织 氧化圆点 缺陷 

分 类 号：TG3[金属学及工艺—金属压力加工]