感应加热中间包钢液氢含量控制

HYDROGEN CONTENT CONTROL OF INDUCTION HEATING OF TUNDISH LIQUID STEEL

重轨钢氢含量是影响质量的关键因素之一。包钢感应加热中间包运行初期,重轨钢等钢种常常出现首炉氢超标的现象。基于此,本文详细分析了感应加热中间包钢液氢含量超标的主要原因,并对中间包材料、耐火材料和连铸工艺进行了优化改造。研究发现,中间包感应加热上线后,预制件数量较多,常规烘烤方式很难实现有效烘烤,这是导致包钢钢液氢含量偏高的主要原因;通过改进耐火材料材质,使用PVC管替代铁皮作为通道模具,利用下线铸坯和中间包的余热以及外置烧嘴对流钢通道预烘烤,烘烤时添加烘烤喷嘴,同时提前对预制件进行烘烤、浇注前氩气置换以及浇注工艺优化等方式,有效实现了浇次首炉氢含量低于2 ppm的目标。中包感应加热运行后生产了154个浇次不同钢种,氢含量全部满足目标要求,同时碳偏析指数平均降低了0.013,提高质量的同时获得了显著的经济效益。

Hydrogen content is one of the key factors affecting the quality of heavy rail steel.In the early stage of operation of induction heating tundish of baotou steel,hydrogen in the first furnace of heavy rail steel often exceeds the standard.Based on this,the main reasons of excessive liquid hydrogen content of induction heating tundish steel are analyzed in detail,and the tundish material,refractory material and continuous casting process are optimized.It is found that after induction heating of tundish comes online,the number of prefabricated parts is large,and the conventional baking method is difficult to achieve effective baking,which is the main reason for the high content of liquid hydrogen in Baotou Steel.By improving the refractory material,using PVC pipe instead of iron sheet as the channel mold,using the waste heat of the cast billet and tundish and the external burner to convection the steel channel pre-baking,adding the baking nozzle during baking,and baking the prefabricated parts in advance,replacing argon gas before pouring and optimizing the pouring process,the goal of hydrogen content below 2 ppm in the first furnace was effectively achieved.After the operation of induction heating,154 different grades of steel were produced,all the hydrogen content met the target requirements,and the carbon segregation index was reduced by 0.013 on average,which obtained remarkable economic benefits while improving quality.