连铸圆管坯中间裂纹成因分析与改进  

Analysis on Cause of Intermediate Crack of Continuous Cast Round Bloom and Improvement

作　　者：张霞[1] 李维[1] 李召岭[1] 刘艳静[1] 

机构地区：[1]天津钢铁集团有限公司技术中心,天津300301

出　　处：《天津冶金》2015年第4期24-26,共3页Tianjin Metallurgy

摘　　要：连铸圆管坯中间裂纹的存在可能导致钢管出现外折或内折,从而造成严重的后果。20钢连铸圆管坯在产品开发初期出现了中间裂纹,通过分析其钢水碳含量、硫含量、磷含量、锰硫比以及连铸二冷制度、铸坯拉速、钢水过热度等影响中间裂纹的因素,确定了中间裂纹产生的主要原因是钢水过热度控制过高,导致铸坯内部柱状晶发达,出现沿柱状晶分布的中间裂纹。通过降低钢水过热度、进一步降低二冷强度并保证冷却的均匀性、确保有效的结晶器电磁搅拌等提高铸坯等轴晶的方式,避免了中间裂纹的发生,稳定了20钢圆管坯的内部质量。The intermediate crack in continuous casting round bloom can cause inner fold and outer fold in steel pipe, leading to serious consequence. Intermediate crack formed at the early stage of the development of round bloom of 20 steel. After analysis was made on factors influencing intermediate crack such as the car- bon content, sulfur content, phosphorus content and manganese and sulfur ratio of liquid steel, secondary cooling system, casting speed and superheat, the main reason for the formation of intermediate crack was de- fined as high superheat which induced the strong growth of columnar grain inside billet, resulting in interme- diate crack along columnar grain. The above crack was eliminated and the internal quality of round bloom of 20 steel stabilized by lowering steel superheat, further reducing secondary cooling strength while maintaining uniform cooling and ensuring effective mould EMS to increase equiaxed grain.

关 键 词：20钢 圆管坯 中间裂纹 改进 

分 类 号：TG245[金属学及工艺—铸造]