Abstract: Cold stretching technique is an effective way to enable thinner wall thickness of the austenitic stainless pressure vessel and thus can achieve lightweight design. In order to investigate the risk increment of the cold stretched vessel, the fatigue behaviors of solution annealed(SA) and cold stretched(CS) S31603 austenitic stainless steel is systematic studied under stress controlling mode at 550 ℃. The results show that：Sustained cyclic hardening response is displayed for both SA and CS material, only the cyclic strain amplitude and mean strain response of CS material is lower than SA one. Abrupt jump of mean strain is found at 550 ℃ which could be attributed to the dynamic strain aging effects. The times of abrupt jump under different cyclic stress for both SA and CS materials are nearly the same. By comparing with the SA material, no more than 10% deformation of the CS material makes the yield strength enhance and the cyclic strain amplitude decrease, which contribute to improve the fatigue life of the material and provide guarantee for reliable operation of the cold stretched austenitic stainless pressure vessel at elevated temperature.

Key words: Austenitic stainless steel, Cold stretching, Elevated temperature, Fatigue, Stress controlled