軟鋼のころがり疲労に及ぼす溶体化処理直後からの負荷運転の影響

抄録

Studies on the characteristics of the rolling contact fatigue strength of mild steel which was solutiontreated and quenched at low temperature have been made. The rolling fatigue test was started immediately after the specimens were solution-treated at 700°C, 650°C or 600°C for 20 minutes and quenched into water bath. The test results of these stress aged specimens were compared with those of the age-hardened specimens after solution treatment and quenching at low temperature. The test was conducted by use of a Nishihara-type wear testing machine under pure rolling contact with lubricant.
The results obtained are as follows;
(1) The rolling contact fatigue strength of mild steel is markedly increased by the stress aging treatment as well as the age-hardening treatment.
(2) The maximum rolling contact fatigue endurance limit of the age-hardened specimens and the stress aged specimens, except the one subjected to solution treatment at 600°C, is shown by the following empirical formula; 3.6·Hv'-290.
(3) At the early stage of the rolling contact fatigue process, work hardening of the stress aged specimen occurs and the contact surface of the specimen becomes smooth.