CSP产线高强钢冶炼关键工艺技术

The research of the key smelting technology of high-strength steel of CSP

通过对比试验确定了采用"BOF→LF→RH→CC"流程生产高强钢WYS700,该工艺流程合金收得率和成分命中率高,过程增氮少,成品氮含量低。为保证浇钢顺利进行,对钢水进行轻钙处理,硅钙线用量0.88 kg/t,轻钙处理工艺后,连浇炉数由4炉提高至7炉。通过扫描电镜观察,中间包钢中非金属夹杂物基本呈球形,分布比较分散,夹杂物的尺寸基本小于5μm,达到了夹杂物变性的目的,改善了钢水可浇性。通过控制钢水成分与温度、优化结晶器倒锥度、调整比水量、优化保护渣与结晶器流场等,高强钢漏钢率由1.90%降低到0.35%,铸坯裂纹改判率由5.5%降低到0.45%。

The BOF→LF→RH→CC process, by which the data shows the higher alloy yield rate and component-targeting rate, and the less nitrogen content in the steel, has been adopted in the production of high-strength steel WYS700 after the contrast test. In order to ensure a smooth casting, the molten steel has been light calcium treated, in which the dosage of calcium silicon was 0. 88 kg/t. After that, the continuous casting has been raised from 4 heats to 7 heats. Through the scanning electron microscope, the nonmetallic inclusion in tundish was observed as sphere and scattered basically, small than 5 μm in principle, which can denature to improve the continuous cast-ability. Through the optimization of component, temperature, water yield, casting powder, and flow field, the breakout rate of high-strength steel was reduced from 1.90 % to 0. 35%, and the crack defective percentage of casting blank was reduced from 5.5 % to 0. 45 %.