Abstract: The production flow sheet for pipeline steel X70 is KR metal pre-desulphuration-180 t BOF-LF-RH-slab CC process. With optimization of refining slag ingredient and slagging operation, and based on effect of bottom gas blowing rate (400-700 L/min) on end [S] , the LF deep desulphurization process has been schemed. Pilot production results show that by controlling refining slag ingredient (/% ) 45-55CaO, 30-40Al₂O₃, ≤10SiO₂ , ≤10Mgo, ≤1.5(TFe + MnO) , with the technology measures including during slagging the lime being added in two separate batch (first in tapping, second at beginning of LF refining) or being added in multi-batch, during LF refining according to slag condition adjusting ingredient of slag, and bottom gas blowing rate 500-700 L/min during LF desulphurization period, the sulphur content in liquid- [S] could be decreased to lower than 10 x 10^-6 in 40 min to meet the requirement of quick deep desulphurization for pipeline steel.

Key words: 180 t LF Refining, Pipeline Steel X70, Deep Desulphurization, Bottom Gas Blowing Rate, Process Optimization

摘要： X70管线钢的生产流程为KR铁水预脱硫-180 t BOF-LF-RH-板坯连铸工艺。通过优化精炼渣成分和造渣制度,以及根据底吹流量(400-700 L/min)对终点[S]的影响,制定了LF深脱硫工艺。生产试验结果表明,通过控制精炼渣成分(/%)45~55CaO、30~40Al₂O₃、≤10SiO₂、≤10MgO、≤1.5(TFe+MnO),造渣时分两批(首次出钢过程第二批LF到站加入)或多批加入石灰,精炼过程根据炉渣情况适当调渣,LF精炼脱硫期的底吹气体流量为500~700 L/min,可在40 min内将钢液[S]降低到10×10^-6以下,满足了管线钢快速深脱硫的需求。

关键词: 180 t LF精炼, X70管线钢, 深脱硫, 底吹气体流量, 工艺优化