耐候钢S355J2W的研发和工艺实践

研发的耐候钢S355J2W(/%:0.06~0.10C,0.20~0.40Si,1.00~1.30Mn,≤0.008S,≤0.020P,0.25~0.40Cu,0.30~0.55Cr,0.10~0.30Ni,0.020~0.040Nb,0.020~0.050Alt)的试生产流程为铁水-120 t顶底复吹转炉-LF-250 mm×2 000 mm板坯连铸-轧制≤16 mm板。通过采取控制转炉终点C]≤0.05%,P]≤0.015%,精炼时(FeO)+(MnO)≤1.5%,(SiO2)≤15%,精炼渣碱度≥3.0,Al]s≥0.025%,按Ca/Al=0.06~0.12,喂入钙线,连铸时采用耐候钢专用保护渣主要成分/%:34.0CaO,28.0SiO₂,4.6Al₂O₃,≤6(Li₂O+B₂O₃)],控制开坯温度1 010~1 060℃等工艺措施,≤16 mm耐候钢S355J2W成品板铝含量为0.025%~0.035%,钢中平均氧含量为21×10^-6,平均氮含量为31×10^-6,钢中非金属夹杂物的尺寸基本≤14μm,各项冶金质量指标合乎要求。

Development and Process Practice of Weathering Steel S355J2W

The pilot production flow sheet for developed weathering steel S355J2W (/% : 0.06 ~ 0. 10C, 0.20 ~ 0.40Si, 1.00-1. 30Mn, ≤0.008S, ≤0.020P, 0.25 ?0.40Cu, 0.30 ~ 0. 55Cr, 0.10 ?0. 30Ni, 0. 020 ~ 0. 040Nb, 0. 020 ~ 0. 050Alt) is hot metal-120 t top and bottom combined blown converter-LF-250 mm x2 000 mm slab CC-≤16 mm plate rolling process. With using the process measures including controlling converter end C] ≤0.05% and P] ≤0. 015%, in refining ( FeO) + ( MnO)≤1. 5%, ( SiO₂) ≤15%, refining slag basicity ≥3. 0, Al]s ≥0.025% and feeding calcium wire according to Ca/Al = 0. 06 ?0. 12, in casting using special-purpose mold shielding flux for weathering steel main ingredient/%: 34.0CaO, 28.0SiO₂, 4.6Al₂O₃, ≤6 ( Li₂O+ B₂O₃)], controlling breakdown temperature 1 010 ~ 1 060℃, the aluminium content in ≤16 mm finished plate of weathering steel is 0. 025% ~0. 035%, the average oxygen content in steel is 21 x 10 ^-6 and the average nitrogen content in steel is 31 x 10^-6, the size of nonmetallic inclusions in steel normally ≤14μm, and each metallurgy quality index meets the requirement of standard.