浇铸超低碳钢减少浸入式水口堵塞的控制工艺

Controlling technology of reducing SEN clogging in ultra low carbon steel casting

邯宝炼钢厂在浇铸超低碳钢时,时常会发生含Al_2O_3的高熔点夹杂物堵塞SEN,造成结晶器液面波动大,严重时会引起塞棒上涨量大,不得不更换SEN。为了减少和避免液面波动量大和SEN堵塞,中间包采用挡墙+挡坝+稳流器的中间包,提高钢水在中间包内的停留时间,增加夹杂物的上浮几率;中包上水口上线前做透气性检测,确保上水口透气均匀,浇铸中能够均匀弥散吹氩,减缓水口堵塞;中间包烘烤前清除中间包内杂物,避免外来夹杂物堵塞SEN;检查各氩气管路透气性和塞棒机构灵活性;浇铸过程中根据结晶器液面活动状态动态地合理的调节中包上水口和塞棒氩气流量和压力。在连铸设备正常和钢水纯净度比较高的前提下,通过以上连铸控制工艺,有效地减少了因SEN内壁夹杂物的附着引起的液面波动以及实现了6炉连浇不更换SEN的目标,进而也提高了铸坯质量。

The SEN is frequently clogged by high melting point Al_2O_3 inclusions when the ultra low carbon steel is casted in Hanbao steelmaking plant. The SEN clogging can lead to large amount of liquid level fluctuation,which cause stopper plugging up,and finally the SEN is forced to replace in order to maintain production. In order to reduce and avoid larger amount of liquid level fluctuation,SEN clogging,it mainly adopted adding to tundish wall,dam and current regulator;increasing the staneling teme of liquid steel in the tundish to improve the floating of incllusions;detecting upper nozzle permeability before using;chucking away foreign matter in the tundish before baked to avoid SEN clogging due to the inclusions;checking kinds of pipeline permeability and stopper mechanism flexibility;adjusting reasonably flow and pressure of nozzle argon and stopper argon according to the mold surface active state at casting. Through taking these measures under normal condition of casting equipments and steel purity,amount of liquid level fluctuation and SEN clogging rate had effectively reduced,and it didn＇t needs replace SEN in six casting. Slab quality was improved.