Austenitic stainless steels are the wide-spread materials, used mainly in the power industry. In that kind of engineering application, structural parts of rotating elements reach during their lifetime very high numbers of loading cycles, exceeding 10⁷ numbers of cycles. With regard on this fact the data of ultra-high fatigue properties are needed to be used in the qualified design. Increasing demands on the efficiency cause the increase of the operating temperature, and exposition of these materials to the elevated temperatures can cause some important structural changes, which result in the sensitising of the structure.

In this study authors present their own experimental results about fatigue properties of austenitic stainless steel AISI 316Ti after sensitising, in the ultra-high cycle region (N=10⁷_~N=5x10⁹ cycles). Fatigue tests were carried out using ultrasonic fatigue testing device with frequency f=20kHz at coefficient of cycle asymmetry R=-1, and temperature T=20±5°C. In the ultra-high cycle region was observed continuous decrease of the fatigue properties of the AISI 316Ti, and there was recorded negative effect of the sensitising on the ultra-high fatigue properties of the AISI 316Ti.