45钢水口结瘤原因及控制

ANALYSIS AND CONTROL OF NOZZLE CLOGGING OF 45 STEEL

研究了45钢生产过程中中间包水口结瘤问题的原因并提出了改进措施。利用高速数据采集系统及EDX荧光分析技术监测了钢液波动情况及水口结瘤物的成分。结果表明:高熔点Al_(2)O_(3)非金属夹杂物和钙处理过程形成的CaS在中间包浸入式水口内壁聚集是水口结瘤的原因。减少Al_(2)O_(3)的产生量,同时防止过量的[Ca]与[S]形成CaS是解决水口结瘤的根本措施。通过将钢水成品钙含量控制在6×10^(-6)~10×10^(-6);LF过程渣料配比二元碱度控制在3.5~5范围,做到硫含量可控,同时硫合金化前置到VD真空前;将LF离站铝含量控制在≤0.015%;VD真空后减少合金化种类,铝合金化后进行钙处理,间隔时间设定为3~5 min;钢水过热度控制在25~35℃等工艺措施改善了45钢的可浇性,实现了整浇次稳定生产,中间包水口结瘤问题随之解决。

In this paper,the problem of nozzle clogging during the production of 45 steel is studied and the improvement measures are put forward.The high-speed data acquisition system and EDX fluorescence analysis technology are used to monitor the fluctuation of molten steel and analyze the composition of nozzle clogs.The results show that the reason for nozzle clogging is the accumulation of high melting point Al_(2)O_(3)non-metallic inclusions and CaS formed during calcium treatment on the inner wall of the nozzle.The fundamental solution is to reduce the amount of Al_(2)O_(3)produced,while preventing the formation of CaS of excessive[Ca]and[S].The process is optimized with the calcium content in molten steel is controlled at 6×10^(-6)~10×10^(-6),the binary alkalinity R of the LF process slag mixture ratio is in the range of 3.5 to 5,achieving a controllable sulfur content.At the same time,sulfur alloying is advanced before VD vacuum;The aluminum content of LF departure station shall be controlled within the range of≤0.015%.After VD vacuum,reduce the types of alloying,and conduct calcium treatment after aluminum alloying.The interval time is set to 3~5 minutes.Control the superheat of molten steel at 25~35℃.After the optimization of the process,the castability of 45 steel is good,stable production of the entire casting process is achieved and the problem of nozzle clogging is also solved.