STP1419: Appropriate Techniques for Internal Cleanliness Assessment

    Auclair, G
    Research Engineer and Metallurgy Department Manager, and Research Engineer, Fatigue Mechanics Department, Ascometal CREAS, Hagondange,

    Daguier, P
    Research Engineer and Metallurgy Department Manager, and Research Engineer, Fatigue Mechanics Department, Ascometal CREAS, Hagondange,

    Pages: 12    Published: Jan 2002


    Abstract

    In the steels used for bearing applications, one of the most important functional properties is fatigue endurance, which is closely related to the micro and macro cleanliness of the metal. Like other bearing steel producers throughout the world (Timken, SKF, Daïdo, Sanyo, etc.), Ascometal has expended considerable effort to attain the very high quality level required to ensure optimum performance in service. To obtain this quality level, the Ascometal philosophy has been to equip its bearing steel plants with appropriate systems for characterizing cleanliness levels both during melting and refining and for the semi-finished products. In particular, optical emission spectroscopy (OES-PDA), quantitative metallography (QM) and ultrasonic testing (high frequency US) were chosen to meet these goals. The equipment available in the different steel plants and the recent improvements made in OES-PDA and US testing procedures are widely described in this paper and examples of the use of this recent knowledge to predict endurance level on the semi-product are presented.

    Keywords:

    bearing steel, nonmetallic inclusion, cleanliness, rolling contact fatigue limit


    Paper ID: STP10848S

    Committee/Subcommittee: A01.28

    DOI: 10.1520/STP10848S


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