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    New Class of High-Speed Steels for Aero Rolling Bearings

    Published: 11 December 2017

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    The load-carrying demands for rolling bearing components are constantly increasing and the bearing materials are required to be progressively durable. The industry is familiar with incremental rolling bearing material improvements and these are well documented. The testing of powder metallurgy high-speed steel (HSS) grades started in the 1970s. The introduction of high cleanliness steel melting, refining, and powder atomization, with consolidation by cold and hot isostatic pressing, resulted in a significant improvement in the metallurgical integrity of powder metallurgy steel HSSs. Cobalt-free HSS based on M62 composition steel (VIM CRU 20) yielded improvements in the rolling bearing function properties. The push for higher load capacities, particularly to support the use of ceramic rolling elements, meant that a new ultra-high hardness class of steel is desired. Cobalt alloying of HSSs is well established for tooling but not for bearings. An HSS with a 10 % cobalt addition has been tested with the aim to use it for demanding aerospace applications. In this paper, the microstructure of the steel (Aerospace Material Specification 6560) has been investigated together with its rolling bearing functional properties. The obtained results are compared to the industry standard vacuum induction melting–vacuum arc refining M50 (Aerospace Material Specification 6490).


    aerospace bearing material, powder metallurgy, Aerospace Material Specification (AMS) 6560, rolling contact fatigue (RCF), single-ball test, multicontact testing

    Author Information:

    Allison, Bryan D.
    SKF Aeroengine, Falconer, NY

    Coudert, Jean-Baptiste
    SKF Aerospace France,

    Guétard, Gaël
    Erasteel—Metallied Powder Solutions, Irun,

    Mondelin, Alexandre
    SKF Aerospace France,

    Vermoere, Renaud
    SKF Aeroengine France, Valenciennes,

    André, Johanna
    Erasteel Kloster AB, Söderfors,

    Bellus, Jacques
    Aubert & Duval,

    Maheo, Yves
    SKF Aerospace France,

    Committee/Subcommittee: A01.28

    DOI: 10.1520/STP160020160131