控制厚板连铸板坯中心偏析的实践

Practice in controlling centerline segregation of continuous casting slab for heavy plate

中心偏析是厚板连铸板坯常见的内部缺陷。阐述了中心偏析的形成机制,并结合湛钢厚板连铸机的生产实践,分析了钢水过热度、二次冷却强度、轻压下工艺优化、辊缝精度控制及二冷设备状况对中心偏析的影响,并采取了相应的改进措施,如低过热度浇注、增加二冷强度、增加轻压下区间和轻压下量、保证辊缝精度及新型二冷喷嘴状态等,显著减少了中心偏析的产生。也得出结论增加轻压下区间和轻压下量及增加二冷强度对减轻中心偏析极为有效。

Centerline segregation is the common inner defect of continuous casting slab for heavy plate. Introduces the formation mechanism of centerline segregation. Effects of the technological parameters,including superheat of liquid steel in casting,secondary cooling intensity,optimization of soft reduction process,control of accuracy of the roll gap and status of secondary cooling equipment,on centerline segregation were analyzed through the production practice of continuous casting machine for heavy plate in Steel-Making Plant of Baosteel Zhanjiang Iron and Steel Co.,Ltd.. Puts forward the countermeasures such as control of low superheat of liquid steel in casting,increasement of secondary cooling intensity,increasement of interval and the amount of soft reduction,control of accuracy of the roller and openness and status of new type secondary cooling nozzles. So that the centerline segregation was reduced remarkably. Also makes a conclusion that increasement of interval and the amount of soft reduction and increasement of secondary cooling intensity are extremely effective to reduce the centerline segregation.