Abstract: Daye Special Steel trial-produced Ф800 mm diameter high carbon chromium bearing steel GCr15SiMn2 large specification forging material through the process of 70 t electric arc furnace +LF + RH refining-20 t die casting ingot-forging ， the products are used to make ≥5MW high power wind turbine main bearings. By means such as controlling the residual elements ［Ti］≤0.001 6%、high basicity slag refining ［CaO（48%-55%）-SiO₂（3%-8%）-Al₂O₃（30%-40%）-MgO（4%-6%）， basicity R≥6］， RH vacuum treatment，protective casting， reasonable pouring process （pouring temperature and speed） ， two times upsetting and stretching process （comprehensive forging ratio ≥4） and other measures， it can meet the microstructure level of steel 1.0 class， the rating of inclusions for B fine， D fine and Ds in steel were 0.5-1.0 class， carbide banding level CZ7.5， the hardenability J45 mm reach 61.0HRC， all performance meet the standard requirements.

Key words: GCr15SiMn2 Die Casting and Forging, High-power Wind Main Bearings, High Carbon Chromium Bearing Steel, Casting Ingot, Upsetting and Stretching Process

摘要： 大冶特钢通过70 t电弧炉→LF→RH精炼→20 t模铸钢锭→锻造的工艺试制出直径ϕ800mm高碳铬轴承钢GCr15SiMn2大规格锻材，产品用于制作 5MW 及以上大功率风电机组主轴承。采用控制钢中残余元素 w［Ti］≤0.0016%、高碱度渣精炼［CaO（48%～55%）-SiO2 （3%～8%）-Al2O3（30%～40%）-MgO（4%～6%），碱度R≥6］、RH真空处理、保护浇注、合理的浇注工艺（浇注温度和速度）及两镦两拔锻造（综合锻造比≥4）等措施，钢材的低倍组织级别 1.0 级，钢中B细、D细、DS 类夹杂物均不大于 1.0 级，碳化物带状级别 CZ7. 5级，钢的淬透性J45mm 达到61.0HRC，各项性能均满足标准要求。

关键词: GCr15SiMn2 模铸锻材, 大功率风电主轴承, 高碳铬轴承钢, 模铸, 镦拔工艺