连铸中间包覆盖剂结壳原因分析及工艺控制

Control process and mechanism analysis for tundish fluxes to form the solidified crusts

中间包渣面结壳不仅恶化中间包冶金效果,还阻碍国内某钢厂智慧连铸工作的推进。为了解决中间包渣面结壳问题,分析钢水温度、中间包渣成分、熔点以及连浇炉数对渣面结壳的影响规律。结果表明,渣层厚度和保温剂的保温效果是中间包渣面结壳主要影响因素。浇注初期,上层覆盖剂保温效果差,中间包渣面熔化成液态。随着连浇炉数增加,渣层热阻增大,中间包渣面重新凝固发生结壳问题。因此,为了改善中间包渣面结壳问题,采用低比重碳化稻壳替代碳化稻球作为保温剂,改善上层覆盖剂的保温效果、阻止浇注初期渣面熔化。现场实施后,一连铸和二连铸中间包渣面结壳率分别从47.3%和35.3%下降到15.0%和10.7%。

The slag crust not only deteriorates the effect of tundish metallurgy,but also hinders the development of smart continuous casting in the steel plant.In order to solve the solidified crusts of tundish fluxes,the effects of steel temperature,composition and melting point of tundish fluxes,and casting heats on the solidified crust at tundish stream zone were investigation in detail.The results show that fluxes thickness and thermal insulating property were the main factors for solidified crust at the tundish stream zone.For the poor fluxes thermal insulating property,the surface of tundish fluxes was melted during the ladle initial pouring stage.With the casting heats increasing,the thermal resistance of the tundish fluxes increasing,resulting in resolidating of the surface fluxes.In order to improving the insulating property of the upper tundish fluxes,the lower specific weight carbonized rice husks were chosen as heat preservation agent instead of carbonized rice ball,preventing the surface of tundish fluxes melt during the ladle initial pouring stage.After implementation,the solidified crust rate of the tundish fluxes in the No.1 continuous casting plant and No.2 continuous casting plant decreased from 47.3%and 35.3%to 15.0%and 10.7%,respectively.