宽厚连铸板坯角部裂纹控制技术开发

 针对直弧型大型连铸机钢液中夹杂物更容易上浮到结晶器液面，有利于降低板坯中的夹杂物质量分数，生产宽厚板坯时角部容易出现横裂纹也容易出现纵裂纹的特点，重钢3号连铸机通过大倒角结晶器技术开发、直弧型连铸机对弧技术优化、板坯宽窄面鼓肚预防等工作降低坯壳所受到的应力；通过大倒角结晶器开发、二冷喷嘴布置优化、二冷动态配水等工作，使板坯温度避开钢的第三脆性区。这两方面综合作用的结果是，2014年2月至12月板坯角部裂纹率为零，解决了板坯角部横裂纹和纵裂纹问题。

Development of corner crack control technology for continuous casting strand of wide-thick plate

For large-scale straight-curve type slab continuous caster,inclusions in moten steel are more likely to float to-wards the meniscus and be removed,which is help for the reduction of inclusions content in the strand. Meanwhile,the corner crack and longitudinal crack are easy to occur during the production of wide-thick slab. In the light of the above, Chongqing steel No.3 continuous caster developed some technologies,such as the adoption of chamfered mold,the im-provement of collating radian precision,the prevention of bulging on the narrow and wide faces,the optimization of the nozzles in secondary cooling zone and the dynamic secondary cooling water mode,to decrease the stress on the solidify-ing shell and make the strand away from the third brittle zone. From February to December 2014,the ratio of corner crack was zero,and the problems of corner crack and longitudinal crack have been solved.