CREEP-FATIGUE BEHAVIOUR OF FOUR CASTS OF TYPE 316 STAINLESS STEEL

Low-cycle fatigue tests including hold periods up to 24 h at maximum tensile strain have been conducted on four casts of Type 316 stainless steel in the temperature range 570 to 625°C. These resulted in failure times up to 4000 h. In general, fatigue life is reduced as the hold period increases, but the extent of life reduction varies from material to material and with test temperature. For two casts material this initial life reduction is followed by an increase in life as hold periods are extended. The results are rationalised in terms of prevailing fracture processes, and the implication for the extrapolation of short-term data is discussed.