关键词: 高压锅炉管用钢15CrMoG , EAF-LF-VD-Φ500mm坯连铸, 低铝, Si-Ca脱氧, 夹杂物

Abstract: The production process flowsheet of steel 15CrMoG for high pressure boiler pipe (/% : 0.12~0.18C, 0.17~0.35Si, 0.40~0.70Mn, ≤0.015P, ≤0.015S, 0.80~1.lOCr, 0.40~0.55Mo, ≤0.020Alt) is 60% hot metal + quality scrap- 100t UHP EAF-LF -VD-Φ500mm bloom casting-rolling. With Al-Si pre-deoxidation in EAF tapping, Si-Ca deoxidation in LF refining, and using optimized refining slag (/% ) : 55~60CaO, 30~35A1₂O₃,5~10SiO₂, (CaO)/( A1₂O₃) =1.41~1.74, the Alt content in refined liquid is 0.011%~0.014%. The analysis results on inclusions in Φ140mm and Φ160mm hot rolled products show that the ingredient of inclusions in steel is 10% MnS, 75% calcium aluminate, 7.5% SiO₂, 5% oxide containing Ti, and 2.5% others, and the ≤5.0μm inclusions make up more than 95% of the total mount of inclusions in steel to meet the technical requirement of steel 15CrMoG for boiler pipe.