Abstract: In order to achieve the goal of high cleanliness of high-speed gear steel，especially the size of single-Particle D spherical inclusions ≤10 μm， electroslag process was developed to produce high-speed rail gear steel 18CrNiMo7-6 （/%：0.15-0.21C， ≤0.40Si，0.50-0.90Mn，1.50-1.80Cr，1.40-1.70Ni，0.25-0.35Mo，≤0.010P，≤0.010S），Φ250 mm steel billet production process is EBT electric furnace -LF-VD- casting 5.6 t electrode billet - electroslag remelting - forging - annealing - inspection. The electroslag slag system of 5.6 t electroslag ingot is CaF₂∶Al₂O₃∶CaO∶MgO=65∶20∶10∶5 ， in the smelting process the melting rate is controlled at 500-550 kg/h，and the slag amount is 180-200 kg. Compared with the old slag system ，after adopting the new slag system the cleanliness of the produced high-speed gear steel is ［O］≤15×10^-6， ［H］≤1.0×10^-6，P≤0.008％，S≤0.005％，and non-metallic inclusion rating of A，B，C ，D and Ds series≤1.0 grade ， and the size of single-Particle D spherical inclusions is≤10 μm. Other hardenability and mechanical properties  meet the requirements.

Key words: 18CrNiMo7-6, High-speed Rail Gear steel, Electroslag Remelting, Cleanliness, Hardenability

摘要： 为达到高铁齿轮钢高洁净度，尤其是单颗粒D类球状夹杂物尺寸≤10 μm的目标，开发了电渣工艺生产高铁齿轮用钢18CrNiMo7-6 （ /%：0.15～0.21C，≤0.40Si，0.50～0.90Mn，1.50～1.80Cr，1.40～1.70Ni，0.25～0.35Mo，≤0.010P，≤0.010S ），Ф250 mm钢坯生产工艺流程：EBT电弧炉-LF-VD-模铸5.6 t电极坯-电渣重熔-锻造-退火-检验。采用5.6 t电渣锭，渣系为CaF₂∶Al₂O₃∶CaO∶MgO=65∶20∶10∶5，冶炼过程中熔化率控制在500～550 kg/h，渣量为180～200 kg，采用新渣系后生产高铁齿轮钢的洁净度为［O］≤15×10^-6，［H］≤1.0×10^-6，P≤0.008%，S≤0.005%，A、B、C、D、DS类非金属夹杂物级别≤1.0级，单颗粒D类球状夹杂物尺寸≤10 μm，淬透性、力学性能等均符合要求。

关键词: 18CrNiMo7-6, 高铁齿轮钢, 电渣重熔, 洁净度, 淬透性