100 t EAF-LF-VD Φ500 mm连铸坯流程高压锅炉用钢SA-210A1生产实践

Commercial Production Practice of Steel SA-210A1 for High Pressure Boiler by 100 t EAF-LF-VD Φ500 mm Bloom Casting Flowsheet

生产的高压锅炉用钢SA-210A1(/%:0.08～0.11C,0.22～0.24Si,0.72～0.74Mn,0.007～0.010P,0.004～0.005S,0.010～0.015V,0.025～0.035Ti,0.012～0.018Alt)的冶金工艺流程为55%铁水+废钢-100 t EAFLF-VDΦ500 mm坯连铸-轧制成Φ130mm圆钢。通过低铝脱氧工艺-EAF终点控制[C]≤0.06%,[P]0.006%～0.010%,出钢加石灰12 kg/t,AD粉(/%:10～13A1,55～60Al_2O_3,5～8SiO_2,5～8Mg0)3 kg/t,700%Al钢芯铝3 kg/t预脱氧;LF采用5.76～6.06高碱度Al_2O_3渣系,LF终点喂0.40 kg/t钙线,软吹≥10 min;中间包钢水过热度15～25℃连铸结晶器和末端电磁搅拌,拉速0.31～0.32 m/min,铸坯缓冷≥48 h等工艺措施,SA-210A1钢中的[0]16×10^(-6)24×10^(-6),[N]65×10^(-6)～80×10^(-6),[Alt]≤0.020%,铸坯和热轧圆钢低倍组织和非金属夹杂物均满足要求。

The metallurgical process flowsheet of produced steel SA-210A1 for high pressure boiler （/% ： 0. 08 ～ 0.11C, 0.22 ～0. 24Si, 0.72 ～0.74Mn, 0.007 ～ 0.010P, 0.004 ～ 0.005S, 0.010 ～ 0.015V, 0.025 ～ 0.035Ti, 0. 012 ～0. 018Ah） is 55% hot metal ＋ scrap- 100 EAF-LF-VD-Ф500 mm bloom casting-hot rolling to Ф130 mm Round bar. With the process measures including low aluminium deoxidation process- EAF end controlling [ C] ≤0. 06% and [ PI 0. 006% ～0. 010%, adding lime 12 kg/t, AD powder （/% ：10～ 13A1, 55 ～60Al2O3, 5 ～8SiO2, 5 ～8MgO） 3 kg/t and 70% Al aluminium cable steel 3 kg/t in tapping liquid for pre-oxidation ; using 5. 76 - 6.06 high basicity Al2O3 slag series in LF refining, feeding 0. 40 kg/t calcium wire at end of LF and sift stirring for ≥10 min; super-heating extent of liquid in tundish 15 -25 ℃ , using mold and end electromagnetic stirring process in casting, casting speed 0. 31 ～ 0. 32 m/min and casting bloom slow cooling for ≥48 h, the steel SA-210A1 steel [ O] is 16 × 10 ^-6～ 24 × 10 ^-6, [ N] is 65 ×10 ^-6 ～ 80 × 10 ^-6 and [ Alt] is ≤0. 020%, the macrostructure and nonmetallic inclusions in casting bloom and hot-rolled round bar all meet the requirements.