Abstract: The production flowsheet for test 250 mm x 250 mm square bloom of EA4T steel for axle (/% : 0. 23C, 0. 32Si, 0. 70Mn, 0. 014P, 0. 010S, 0. 18Mo, 0. 03V) is 60 t EBT EAF- LF- VD- 8. 4 t ingot casting- rolling- annealing process. The effect of 880 - 920 °C oil quenching and 600 - 650 °C tempering, process on structure and mechanical properties of the steel is tested and studied. With 920 °C +600 °C , 920 °C +650 °C and 880 °C +640 °C quenching-tempering treatment, the structure of steel is respectively martensite, sorbite + martensite and martensite + bainite； the mechanical properties of steel EA4T treated by 880 °C +640 °C quenching-tempering process are R_p0.2-525 MPa, R_m-720 MPa, .A₅-23% , U-5 mm longitudinal impact energy- 68 - 82 J and cross-sectional impact energy- 65 - 86 J, and its structure and mechanical properties all meet the requirement of standard EN13261.

摘要： 试验用250 mm×250 mm方坯EA4T车轴用钢（/%:0.23C,0.32Si,0.70Mn,0.014P,0.010S,0.18Mo,0.03V）的生产流程为60 t EBT EAF-LF-VD-8.4 t铸锭轧制-退火工艺。试验研究了880~920℃油淬、600~650℃回火工艺对该钢组织和力学性能的影响。经920 C+600℃、920℃+650℃和880℃+640℃淬-回火处理后,该钢的组织分别为马氏体、索氏体+马氏体和马氏体+贝氏体;880℃+640℃淬-回火处理后EA4T钢的力学性能为R_p0.2 525 MPa,R_m 720 MPa,A₅ 23%,U-5 mm纵向冲击功68~82 J,横向冲击功65~86 J,其组织和力学性能均符合EN13261标准要求。

关键词: 250 mm x 250 mm方坯, EA4T车轴用钢 , 淬-回火处理, 组织 , 力学性能