Abstract
Bearing steel (JIS: SUJ2) heat treated to hardness value above HRC 58 has been overwhelmingly used for rolling bearings, ball bushes, and ball splines with rounded shape rolling machine elements. It is thought that for this material when the fatigue test is carried out, in the domain of high cycle fatigue of the S-N curve- the so-called Wöhler curve, a fatigue limit appears. This type of fatigue limit has been used in the ISO standard of the year 2000 with a life modification factor axyz for rolling bearings. However, at present even in the life test of bearing or S-N fatigue test of material, the experimental data does not show any apparent sign of the fatigue limit. In this research work, alternating torsion fatigue test for probabilistic stress life (P-S-N) evaluation is carried out under standard stress values, from τ = 1GPa to τ = 0.5GPa for 5 lots made up of a total of 150 samples, and P-S-N curves were determined based on the three-parameter Weibull and lognormal distribution. Based on this result, it is reported that the bearing steel does not show a fatigue limit.
