Relation between Oxide Inclusion on the Rolling Track and Flaking

Abstract

The results stated below have been revealed on the relationship between the plate-like carbides which form immediately under the rolling track and oxide inclusions present on the track for the specimens tested in the ball/washer thrust type rolling contact fatigue testing machine.
1) The plate-like carbides precipitate as carbon diffuses by rolling contact stress in an area of stress concentration between the oxide inclusions on the rolling track and those immediately under the track.
2) In the specimens made of vacuum degassed steel, the plate-like carbides begin to present themselves after approximately 10⁶ stress repetition at P_max of 500 kgf/mm², although its rate depends on amount and size of the inclusions.
3) The oxide inclusions found in specimens of the thrust type tester for rolling fatigue do not have a direct influence on causing cracks as stress concentration source. Their stress concentration effects rather work as intermediary to produce the plate-like carbides.