STP987

    Quality of High-Carbon Chromium Bearing Steel Produced in the Electric Arc Furnace—Ladle Furnace—RH Vacuum Degassing Vessel—Vertical Continuous Caster

    Published: Jan 1988


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    Abstract

    The quality of high-carbon chromium bearing steel, SUJ2 (SAE52100), produced by the electric arc furnace (EF)-ladle furnace (LF)-Ruhrstahl-Heraeus vacuum degassing vessel (RH)-vertical type continuous caster (CC) process, including the effects of impurities and cold working on its fatigue life, was investigated.

    Bearing steel made in the experimental 100-kg induction furnace was also subjected to a fatigue life test in order to confirm the effect of impurities. The substantially low oxygen content of the CC bearing steel has resulted not only in high cleanliness which doubles the life of conventional ingot steel, but also in the reduction of buildup of nonmetallic inclusions on the inner surface of an immersion nozzle. Due to this reduction, approximately 10 000 metric tons (68 heats) of steel can be cast from one tundish-one nozzle without interruptions.

    The fatigue life test was performed on specimens where the center segregation of bearing steel lay on their running surfaces with results that flaking sites did not tend to concentrate in the center portion. In other words, tests were done when center segregation did not affect the life of the specimen.

    It has become clear that the fatigue life of the CC-bearing steel, despite reduced impurities, still depends mainly on the oxygen content of the steel. Also, the life test on the specimens made in the experimental furnace has confirmed that titanium and sulfur are hardly related to the life as long as their contents are kept at levels generally found in commercial bearing steel.

    The life was further extended by cold working even when the oxygen content was extremely reduced. The bearing steel manufactured by the EF-LF-RH-CC-cold working process is accordingly considered to exhibit the longest life in commercially mass produced bearing steel.

    Keywords:

    high-carbon chromium bearing steel, vertical continuous caster, rolling contact fatigue, nonmetallic inclusion, oxygen, impurity, center segregation, cold pilger


    Author Information:

    Uesugi, T
    President and senior research engineer, Sanyo Special Steel Co., Ltd., Himeji,

    Tsubota, K
    President and senior research engineer, Sanyo Special Steel Co., Ltd., Himeji,


    Paper ID: STP26241S

    Committee/Subcommittee: A01.28

    DOI: 10.1520/STP26241S


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