100 t EAF-LF-VD-CC流程冶炼非调质钢49MnVS3的工艺实践

10炉非调质钢49MnVS3(/%:0.46~0.48C,0.30~0.40Si,0.88~0.92Mn,0.001~0.014P,0.004~0.005S,0.09~0.10V,0.19~0.22Cr)由100 t EBT DC EAF-LF-VD-260 mm×340 mm坯连铸-Φ140~150 mm材轧制流程生产。采用兑入75%铁水,EAF前期脱磷至≤0.015%P,出钢前C]为0.20%~0.30%,精炼时加150~200kg碳化硅,控制LF精炼渣碱度2.80~2.95,(CaO)/(Al₂O₃)=1.2~1.6,VD后喂1.5 m/t钙铁线,软吹时间≥15min等工艺措施,49MnVS3钢中N]、H]和O]分别为130×10^-6~220×10^-6,1.2×10^-6~1.5×10^-6和5×10^-6~11×10^-6,成品材晶粒度≥5级,非金属夹杂物和低倍组织均≤1.5级,组织(带状≤1级)和力学性能(R_m 803~883 MPa,R_el 517~590 MPa, A 16%~21%,A_ku 39~99 J)均满足标准要求。

Process Practice of Non-Quenched-Tempered Steel 49MnVS3 Steelmaking by 100 t EAF-LF-VD-CC Flowsheet

10 heats of non-quenched-tempered steel 49MnVS3 (/% : 0.46 ~ 0.48C, 0,30 ~ 0.40Si, 0.88?0.92Mn, 0.001~0. 014P, 0.004 ~ 0.005S, 0.09~ 0.10V, 0.19 ~ 0.22Cr) are produced by 100 t EBT DC EAF-LF- VD-260 mm x 340 mm bloom casting-Φ140 ?150 mm round bar rolling process flowsheet. With using the process measures including charging 75% hot metal, in EAF earlier period dephosphorizing to ≤0.015%P, before tapping controlling 0.20% ~0. 30% C] , in refining adding 150 ~200 kg silicon carbide, controlling LF refining slag basicity 2. 80 ~2. 95 and ( CaO)/( Al₂O₃) = 1.2 ~ 1. 6, after VD feeding 1. 5 m/t calcium-iron wire and soft argon blowing for ≥15 min, the N] , H] and O] of steel 49MnVS3 are respectively 130 x 10^-6 - 220 x 10^-6, 1.2 x 10^-6 - 1.5 x 10^-6 and 5 x 10^-6 ~ 11 x 10^-6 , finished products grain size is N5 rating, nonmetallic inclusions and macrostructure are all ≤ 1. 5 rating, the structure (banded orientation ≤1 rating) and the mechanical properties (R_m 803 ~883 MPa, R_el 517 ?590 MPa, A 16% ~21%, A_ku39~59J) all meet the requirement of standard.