20CrMnMoH钢中间裂纹成因分析及改进实践  

Cause Analysis and Improvement Practice of Intermediate Crack in 20CrMnMoH Steel

作　　者：李铁[1] 邹虎 赵文渊 宋邦民 LI Tie;ZOU Hu;ZHAO Wenyuan;SONG Bangmin(Shandong Taishan Iron and Steel Group Co.,Ltd.,Jinan 271100,China;Wuhu Xinxing Ductile Iron Pipes Co.,Ltd.,Wuhu 241000,China)

机构地区：[1]山东泰山钢铁集团有限公司,山东济南271100 [2]芜湖新兴铸管有限责任公司,安徽芜湖241000

出　　处：《山东冶金》2023年第1期26-29,共4页Shandong Metallurgy

摘　　要：针对某钢厂生产的Φ600 mm 20CrMnMoH大圆坯低倍出现的中间裂纹的问题,通过低倍酸洗和金相显微镜对铸坯中间裂纹进行观察,并结合钢水成分和连铸过程控制,分析认为连铸二冷区水量分配不合理和铸坯缓冷效果不好,是造成本次中间裂纹缺陷的主要原因。通过降低二冷比水量至0.08 L/kg,优化二冷区三段水量分配比为45∶34∶21,使铸坯矫直处表面温度≥900℃;改造缓冷坑及优化缓冷工艺,采用热坯垫坑,入坑温度≥600℃,缓冷时间≥72 h,出坑温度≤200℃,避免了大圆坯中间裂纹的出现。For the problem of intermediate crack appearing in low doubling of large round billet produced by a steel plant,the cracks in the middle of the billet were observed by macrostrcture pickling and metallographic microscope,and combined with the composition of molten steel and the control of continuous casting process,the analysis shows that unreasonable water distribution in the secondary cooling zone of continuous casting and poor slow cooling effect of casting billet are the main reasons for the intermediate crack defects.By reducing the secondary cooling specific water to 0.08 L/kg,the water distribution ratio of the three stages of the secondary cooling zone is optimized to 45∶34∶21,so that the surface temperature of the straightening billet is more than 900℃.The slow cooling pit is reformed and the slow cooling process is optimized.The hot billet pad pit is adopted.The pit entering temperature is more than 600℃,the slow cooling time is more than 72 h,and the pit exit temperature is less than 200℃,which avoided the appearance of cracks in the middle of the big round billet.

关 键 词：20CrMnMoH钢 中间裂纹 二冷工艺 缓冷 

分 类 号：TF777[冶金工程—钢铁冶金]