Study on Rotating Bending Fatigue Characteristic of Several Stainless Steels at High Temperature

Abstract

The rotating bending fatigue tests were carried out at room temperature, 200°C, 400°C, 600°C and 800°C with a frequency of 1200 cycles/min. using SUS 304 solution treatment material and SUS 304-1/2 H 10% cold working material, and were carried out at room temperature, 300°C and 600°C using SUS 430 and SUS 403. The cold working material showed higher strength at finite life and fatigue limit in every temperature than the other materials did, although the difference of fatigue limit above 400°C between the cold working material and the other materials were a little. The relationships between the fatigue limit σW and the tensile strength σB were obtained as σW =0.44σB for SUS 304 at every temperature and SUS 304-1/2 H over 200°C, and σW=0.58σB for SUS 430, SUS 403 at every temperature and SUS 304-1/2 H below 200°C. Besides, the relationship between the stress ratio σa/σωR.T. and the parameter P= (10-log Nf) /T was proposed to estimate the fatigue strength at finite life, where σa is the bending stress amplitude, σωR.T. is the fatigue limit at room temperature, Nf is the cycles to failure and T is the absolute temperature.