120 t复吹转炉高拉碳低磷出钢的冶炼工艺改进

The Smelting Process Improvement of 120 t Top-Bottom Combined Blown Converter with High-Carbon Turndown and Low Phosphorus Tapping

转炉冶炼重轨钢、轴承钢等高碳钢,氧枪控制采用传统低-高-低三段式冶炼模式,因前期石灰难以熔化、中期喷溅加剧、后期失去高碱度脱磷机会,造成冶炼过程喷溅率高、终点拉碳合格率低等问题。为解决此问题,通过冶炼工艺分析,采用改进后的氧枪控制为高-低-低-高-低五段式新冶炼模式。其综合结果为冶炼过程喷溅率明显降低,喷溅率由20%~30%降低到15%以下;终点拉碳合格率大幅提升,终点拉碳合格率由69.06%提高到93.55%。

High carbon steel such as heavy rail steel and bearing steel are smelted by converter,the traditional low-high-low three-stage smelting mode is adopted for oxygen lance control.Because lime is difficult to melt in the early stage,splash intensifies in the middle stage and loses the opportunity of dephosphorization with high alkalinity in the later stage,the splash rate is high in the smelting and the qualified rate of carbon turndown at end-point is low.In order to solve this problem,a new high-low-low-high-low five-stage new smelting model is adopted by analyzing the smelting process.The results show that the splash rate is obviously reduced from 20%~30%to less than 15%,and the qualified rate of carbon turndown at end-point is greatly increased from 69.06%to 93.55%.