四球試験におけるラジカル窒化処理軸受鋼 SUJ2 の焼付き強さ

概要

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To clarify the seizure resistance of radical nitrided bearing steel SUJ2,a four-ball test was carried out under dip-feed lubrication using a Soda four-ball machine. Four kinds of the combination of the ball pair were tested. The symbol N-N indicates the ball pair without nitrided, the symbol R-N indicates the ball pair in which only stationary ball was nitrided, the symbol N-R indicates the ball pair in which only rotatory ball was nitrided and the symbol R-R indicates the ball pair in which both stationary and rotatory ball were nitrided. From the test, the following results were obtained. (1) At the load stage before seizure, the value of coefficient of friction μ with ball pair N-R was the smallest of all ball pairs, and was about 0.07. (2) The order of the seizure resistance of the ball pairs was N-R>R-R>R-N>N-N. The seizure resistance for ball pair R-R was about 2.6 times as high as that for ball pair N-N, and a significant effect of the heat treatment due to radical nitriding on increasing the seizure resistance of bearing steel with a small amount of Cr content was recognized. (3) With ball pairs N-N and R-R, the critical surface temperature θ_<cr> at the risk for seizure was about 369∿376℃. The values of θ_<cr> with ball pairs R-N and N-R were about 495 and 302℃, respectively.
2001-10-25