HIGH-TEMPERATURE ROTATING BENDING FATIGUE BEHAVIOR OF A MARTENSITIC STAINLESS STEEL SUS 403-B.

Rotating bending fatigue tests were carried out on a martensitic stainless steel (Type 403) at room temperature, 200, 300, 400, 450 and 500 degree C, with a frequency of 7500 cycles per minute and the fatigue strength at 10**8 cycles was obtained by the staircase method. The endurance limits were found, and the fatigue strengths at 10**7 and 10**8 cycles were identical at 200 and 300 degree C and were nearly equal at room temperature and 400 degree C. At 450 and 500 degree C, the number of cycles to failure continued to increase with decreasing stress amplitude up to 10**8 cycles. The strengthening of the material is considered to be caused by dynamic aging during the fatigue test at 200 to 400 degree C.