提高含硫含铝齿轮钢钢液洁净度实践

Improving cleanness of liquid of sulfur and aluminum bearing gear steel

针对石家庄钢铁有限责任公司生产含硫含铝钢时难以实现多炉连浇的状况,研究了利用"LD→LF→VD→CC"流程生产此类钢过程中提高钢液洁净度,改善钢水可浇性的系统工艺技术。通过开发转炉终点高碳出钢技术、出钢Al-Si-Al脱氧技术、含硫含铝钢LF专用精炼造渣技术、LF及VD精炼分阶段变流量底吹氩技术及连铸防氧化保护浇铸技术等,实现了此类钢连浇8炉以上。轧材检测发现:全氧质量分数降低到12×10-6以下,夹杂物缺陷率由2.3%降至0.6%,超声波探伤合格率由65%提高到93.5%。

According to the fact that it is difficult to achieve multiple ladles continuous casting for the steel bearing sulfur and aluminum in Shijiazhuang Steel Co. , Ltd. , the smelting technology for improving the cleanliness and castablity with LD→LF→VD→CC is systematically studied for this steel. The following technologies are developed： high carbon control in the end of converter, Al-Si-Al deoxidation type during steel tapping, special refining slag for this steel, variation of argon blowing with the refining time, protective casting with repressing oxidize when continuous casting. The results show that, it can casting more than 8 heats. Affter rolling bars, the total oxygen content is lower than 12 × 10^-6, the inclusion ratio decreases to 0. 6% from 2.3 %, the UT qualified rate increases from 65% to 93.5 %.