Abstract: By 120 t converter-LF refining-continuous casting-controlled rolling and cooling process,the 750L (Rm≥ 750 MPa)beam steel of 8 mm high strength automobile is succes fully developed. The results show that through 750L steel Nb-Ti composite microalloying(/%:0.074C,0. 11Si,1.51Mn,0.020P,0.002S,0.042Als,0.033Nb,0. 109Ti), combined with control rolling and cooling(finish rolling reduction≥40%),that of produced  750L  steel  strip, the  tensile strength  782～810 MPa, elongation≥17.5%, grain  size11.5～12.5 rating  and  impact  energy ≥90 J, all technical  indexes satisfy the requirements of standard.

摘要： 采用120 t BOF-LF-连铸-控轧控冷工艺流程，开发出8 mm高强度汽车大梁钢750L（R_m≥750 MPa）。结果表明，通过750L钢Nb-Ti复合微合金化（/%:0.074C，0.11Si，1.51Mn, 0.020P，0.002S，0.042Als，0.033Nb，0.109Ti），结合控轧控冷技术（精轧区压下量≥40%），生产的750L钢带的抗拉强度782～810 MPa，伸长率≥17.5%，晶粒度11.5～12.5级，冲击功≥90 J，各项技术指标满足并优于标准的要求。