高温不锈渗碳轴承钢的研发现状与进展

 航空用轴承钢向耐高温、耐腐蚀、高承载、长寿命方向发展,现役的M50轴承钢存在强度高但韧性和耐蚀性不足的问题;M50 NiL渗碳轴承钢虽然通过降低碳含量和调整合金成分来提高韧性,但仍越来越无法满足高推重比的航空发动机的发展需求,并且耐蚀性不足问题也未解决。高铬不锈轴承钢BG-42和高氮Cronidur30轴承钢虽然抗腐蚀能力好,但是表面硬度和心部韧性仍不足。以CSS-42L钢为代表的高温不锈渗碳轴承钢拥有高强韧性和优良耐蚀性能,不仅在航空轴承应用上极具竞争优势,而且也可应用于在高温或腐蚀性环境下使用的齿轮、轴和紧固件等,但是国内外相关研究工作仍不足且缺乏系统性,因此对其研发现状进行综述和总结尤为重要。从航空用高温轴承钢发展历程出发,详细介绍了国内外高温不锈渗碳轴承钢的研发背景和合金成分设计思路;综述了铬、钴、钼、镍、钒、钨等主要合金元素对组织和性能影响规律,其中钴的加入虽然不直接参与析出强化,但能够起到抑制δ-铁素体形成和促进弥散析出的特殊作用;分别从表面渗碳和心部材料两个方面,揭示了调控热处理工艺对微观组织和强韧性的影响规律。在此基础上,针对国内外高温不锈渗碳轴承钢基础理论和制造工艺研究的不足,提出了优化合金成分、突破渗碳热处理技术,以及加强不同工况下组织演变、疲劳损伤和破坏机理研究的研发方向。

Research status and progress of high temperature stainless carburized bearing steel

Aviation bearing steel is developing towards high temperature resistance, corrosion resistance, high load bearing and long service life. The M50 bearing steel on service has the problems of high strength but insufficient toughness and corrosion resistance. Although the toughness of M50 NiL carburized bearing steel is improved by reducing C content and adjusting alloy composition, it still can't meet the development needs of aeroengines with high thrust weight ratio in future, and the problem of insufficient corrosion resistance has not been solved. Although high chromium stainless bearing steel BG-42 and high nitrogen bearing steel cronidur30 have good corrosion resistance, their surface hardness and core toughness are still insufficient. High temperature stainless carburized bearing steel represented by CSS-42L steel has high strength, toughness and excellent corrosion resistance. It not only has great competitive advantages in aviation bearing application, but also can be applied to gears, shafts and fasteners used in high temperature or corrosive environment. However, relevant research work at home and abroad is still insufficient and lack of systematicness. Therefore, it is particularly important to summarize its research and development status. Based on the development history of aviation high temperature bearing steel, the research and development background and alloy composition design idea of high temperature stainless carburized bearing steel at home and abroad are introduced in detail. The effects of main alloy elements such as Cr, Co, Mo, Ni, V and W elements on microstructure and properties are reviewed. Although the addition of Co element does not directly participate in precipitation strengthening, it can inhibit precipitation δ-ferrite formation and have a special effect of promoting dispersion precipitation. The effects of heat treatment process on microstructure, strength and toughness were revealed from two aspects: surface carburization and core material. In view of the shortcomings of the research on the basic theory and manufacturing process of the high temperature stainless carburized bearing steel at home and abroad, the research and development directions of optimizing alloy composition, breaking through carburizing heat treatment technology, and researching microstructure evolution, fatigue damage and failure mechanism under different working conditions are put forward.