Abstract: The production flowsheet of oil-quenched at 890 ℃ for 300 s and tempered at 530℃ for 1200 s Φ22 mm rod of spring steel 55SiCrA (/% : 0.55C, 1.45Si, 0.67Mn, 0.010P, 0.005S, 0.68Cr) is hot metal desulphurization- 80 t top and bottom combined blowing converter- LF- RH- 280 mm x 325 mm bloom casting-Φ22 mm rolling products. Examination results show that the center segregation rating of Φ22 mm rolled products of steel 55SiCrA is 3 , the carbon content at center of rod is non-homogeneous i. e. 0.50%-0.60% C, and the carbon content at 1/2 radius of rod is 0.54% ; of steel specimen at center the tensile strength is 1430-1455 MPa and the reduction o£ area is 39%-40% , while of steel specimen at 1/2 radius of rod the tensile strength is 1470-1480 MPa and the reduction of area is 43.0%-45.5% , the serious center segregation ( rating 3) leads to obvious decrease of mechanical properties of oil-quenched and tempered spring steel 55SiCrA.

Key words: Spring Steel 55SiCrA, Center Carbon Segregation, Oil-Quenching and Tempering, Mechanical Properties

摘要： Φ22 mm油淬回火（890℃ 300 s油淬,530℃ 1200 S回火）55SiCrA弹簧钢丝（/%:0.55C,1.45Si,0.67Mn,0.010P,0.005S,0.68Cr）的生产流程为铁水脱硫-80 t顶底复吹转炉-LF-RH-280 mm×325 mm方坯连铸-Φ22 mm轧材。试验结果表明,55SiCrA钢Φ22 mm轧材的中心偏析为3级,中心处碳含量不均匀为0.50%~0.60%C,半径1/2处的碳含量为0.54%;中心处试样抗拉强度1430~1455 MPa,断面收缩率39%~40%,半径1/2处抗拉强度1470~1480 MPa,断面收缩率43.0%~45.5%,严重的中心碳偏析（3级）使油淬回火55SiCrA弹簧钢的力学性能明显降低。

关键词: 弹簧钢55SiCrA, 中心碳偏析, 油淬回火, 力学性能