780 MPa双相钢炼钢工艺控制实践

针对DP780炼钢工艺中对P]、S]、H]的要求,对转炉脱磷及挡渣方式进行了优化,保证中间包P]≤0.015%;通过铁水预处理与LF共同脱硫,保证中间包S]≤0.003%;采用RH脱气处理,控制钢水中H]≤4×10-6。对比了不同过热度及拉速下的铸坯质量,提出了过热度20~30℃及拉速≥1.2m/min的控制要求。优化后的炼钢工艺保证了780 M Pa双相钢的产品质量。

PRACTICE OF STEELMAKING PROCESS CONTROL OF 780 MPA DUAL-PHASE STEEL

The converter dephosphorization and slag-stopping methods were optimized to ensure P] ≤ 0.015% in the tundish, according to the requirements for P], S] and H] in the DP780 steelmaking process.The combined desulfurization in hot metal pretreatment and LF ensures S] ≤ 0.003% in tundish.H] is controlled not higher than 4 × 10-6 in molten steel with RH degassing treatment.Through the comparison of slab quality with the different superheat and casting speed, the control requirements of superheat degree of 20 ~ 30 ℃ and speed of ≥1.2 m / min were put forward.The optimized steelmaking process ensures the product quality of the 780 MPa duplex steel.