氩气保护ESR对EAF-LF-VD-CC冶炼的高速车轴钢DZ2轧坯质量的改善

采用EAF-LF-VD-Φ690 mm铸坯和EAF-LF-VD-Φ690 mm铸坯-Φ740 mm ESR锭两种工艺分别制备了250 mm × 250 mm高铁车轴用DZ2钢轧坯,并研究了其低倍组织、夹杂物、碳偏析、金相组织和力学性能。结果表明:相比于电弧炉流程工艺,电渣重熔工艺得到的DZ2钢轴坯中心疏松和一般疏松从0.5～1.0级降低到0～0.5级,夹杂物尺寸从2.43～25.05 μm降低到1.42～9.32 μm,夹杂物形貌由棒状变为球形;横截面上碳含量分布从0.256%～0.269%降低到0.261%～0.265%,碳极差从0.013%降低到0.004%;屈服强度和抗拉强度分别提高了17.5%和13.8%,20℃横向和纵向冲击功分别提高36.2%和17.8%。

Improvement on Quality of Rolled Billet of EAF-LF-VD-CC Steelmaking High-Speed Railway Axle Steel DZ2 by Argon Shielding ESR

The 250 mm x 250 mm rolled billets of high-speed railway axle steel DZ2 are rolled, by EAF-LF-VD-?690 mm cast bloom and EAF-LF-VD-?690 mm cast bloom-?740 mm ESR ingot of two processes. The macrostructure, inclusions ,carbon segregation, microstructure and mechanical properties of the blooms are studied. The results show that: compared with EAF process flowsheet, the rating of central porosity and general porosity of DZ2 steel shaft billet obtained by ESR process reduces from 0.5 ~ 1.0 to 0 ~ 0.5 grade； the size range of inclusions reduces from 2.43 ~ 25. 05μm to 1. 42 ~ 9. 32μm, and the morphology of inclusion changes from rod-shaped to spherical； the carbon content distribution on cross-section reduces from 0.256% ~ 0.269% to 0.261 % ~ 0.265% , and the carbon range difference reduces from 0.013% to 0.004% ; the yield strength and tensile strength increase by 17.5% and 13.8% , respectively, and the transverse and longitudinal impact energy at 20℃. increase by 36.2% and 17.8% , respectively.