防止超低碳铝镇静钢大方坯连铸水口堵塞的工艺实践

Practice of Process to Prevent Nozzle Clogging During Bloom Concasting of Ultra-Low-Carbon Aluminium-Killed Steel

研究了铁水脱硫预处理-80 t顶底复吹转炉-LF-RH-280 mm×325 mm方坯连铸流程生产XGM6钢(/%:0.012C,≤0.012Si,≤0.08Mn,≤0.015P,≤0.010S)等超低碳铝镇静钢时水口堵塞的原因和防止措施。通过控制转炉终点[O]≤600×10^(-6),LF顶渣为高铝渣+电石,RH-OB脱碳后加铝粒脱氧,控制RH终点氧含量20×10^(-6)~30×10^(-6),RH终点[Al]s≤0.009%,中间包钢水过热度25~40℃,[Al]s≤0.004%等工艺措施,基本避免超低碳铝镇静钢水口堵塞,连浇炉数由不足2炉提高到8炉以上。

Abstract The cause and preventing measures for nozzle clogging during steelmaking process of ultra-low-carbon alu- minium-killed steel such as XGM6 steel （/% ： 0. 012C, ≤0. 012Si, ≤0. 08Mn,≤0. 015P, ≤0. O10S） produced by hot metal pre-desulphurization process-80 t top and bottom combined blown converter-LF-RH-280 mm x 325 mm bloom concast- ing flow sheet have been studied. With using the process measures including controlling converter end [ O]≤600 ×10-6, LF top slag- high alumina slag ＋ carbide, deoxidizing by adding aluminium shot after RH-OB decarburisation, controlling RH end [ 0 ] 20 ×10-6-~ 30 ×10-6, RH end [ A1 ] s ≤ 0. 009%, tundish liquid superheating extent 25 - 40 ℃ and [ A1 ] s≤0. 004%, the nozzle clogging of liquid of ultra-low-carbon aluminium-killed steel has basically been avoided, continuous- continuous casting heats increase from less than 2 heats to more than 8 heats.