焊线钢渣洗直上工艺实践探究

针对首钢长钢公司在焊线钢开发过程中,采用渣洗直上工艺即转炉—出钢渣洗和氩站吹氩—连铸的工艺流程替代LF过电精炼深处理工艺流程的试验,通过对一系列试验数据的详细分析研究,得出渣洗直上工艺在脱硫、增碳及夹杂物控制等方面的效果。研究结果表明:渣洗直上工艺平均脱硫率17.25%;夹杂物类型与LF过电精炼工艺基本相同,数量也可以达到LF精炼水平。通过优化焊线钢渣洗直上工艺,既能满足产品质量要求,又能有效降低生产成本。

低碳铝镇静钢SPHC-2浸入式水口堵塞原因及预防措施

裕华钢铁在生产SPHC-2深冲钢时采用吹氩直上工艺,有利于钢厂降低工序成本,但此类钢种在连铸过程中钢水可浇性较差,水口下部堵塞严重,铸坯质量和轧材缺陷突出,综合合格率99.87%,低于国内先进同行,造成企业综合成本升高。须对现有工艺进行调整和优化,提高钢水洁净度,解决钢水可浇性问题,提高产品质量和竞争优势。

Direct reduction of carburized pre-reduced pellets by microwave heating

A new iron-making process using carburized pre-reduced iron ore pellets and microwave heating is investigated. The pre-reduced pellets, with a porous structure, and fine particles are carburized homogeneously at 400-650 ℃ in a CO atmosphere. The carburized carbon not only acts reaction as a reduction agent, but also absorbs microwave in the reduction process. Hence, the carburized pre-reduced pellets can be rapidly reduced by microwave heating. There are three procedures involved in the process, namely, gas-based pre-reduction, low-temperatttre carburization and deep reduction by microwave heating. Carburized pre-reduced iron ore pellets show a rapid temperature rise that is twice as fast as the results for pre-reduced pellets in the laboratory. This not only improves the efficiency of the microwave heating, but also accelerates the reduction of iron oxides. The temperature of the pre-reduced pellets rises to 1050 ℃ in 45 min when the carburization rate is 2.02%, and the metallization rate and compressive strength reach 94.24% and 1725 N/pellet, respectively.

230 mm厚板坯表面纵裂成因分析及改进措施

某钢厂1台230 mm×1 410 mm双流板坯连铸机采用转炉直上工艺浇铸Q235B钢时,板坯出现表面纵裂纹。针对该钢厂的铸坯质量缺陷进行现场工艺追踪,对比和分析转炉工艺、钢水成分控制、结晶器水冷工艺、结晶器保护渣等关键工艺控制点,并采取了相关的针对性工艺改进措施,表面纵裂纹综合发生率成功从16.52%降低至1.25%、纵裂纹超深改判率从4.16%降低至0.18%。