STP1327

    Laser Glazed Bearings

    Published: Jan 1998


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    Abstract

    In the past decade high power, reliable, carbon dioxide lasers have become commercially available. Laser glazing is a process in which a focused laser beam is used to melt a very small portion of a component. As the beam moves away from the melted region, the underlying mass of the component causes the liquid pool to rapidly solidify. A major advantage of laser glazing is that the refined structure is only created in areas where high load carrying capacity is required

    Initially rods manufactured from BG 42 and M 50 steels were laser glazed. Laser glazing transformed the normal, fine grain, martensitic steel matrix into a very fine dendritic microstructure. The carbides in the laser glazed material were greatly reduced in size due to very rapid solidification. Using a standard ball / rod rolling contact fatigue tester, enhanced rolling contact fatigue life was realized from the laser glazing process.

    LM 12749 tapered roller bearing cones were fabricated from M 50 high speed steel and laser glazed. At 200% catalog load, the L15.9% life of the laser glazed M 50 bearings was 370% greater than the wrought cones. Similarly, when tested at 300% catalog load, the laser glazed bearings had L15.9% life 580% greater than the wrought cones.

    Laser processing has been applied to 440 C stainless steel. In this alloy similar reduction in the size and distribution of large chromium carbides was achieved. The glazed 440 C was approximately 20 Knoop hardness points higher than the wrought alloy. Examples and properties of glazed microstructures in ball bearings and other alloy systems are discussed.

    Keywords:

    laser glazing, rolling contact fatigue, bearing life, high speed steel, martensitic stainless steel, carbide distributions


    Author Information:

    Hetzner, DW
    Research Specialist, The Timken Company, Canton, OH


    Paper ID: STP12146S

    Committee/Subcommittee: A01.10

    DOI: 10.1520/STP12146S


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