Fatigue Behavior of Stainless Steel Sheet Specimens at Extremely High Temperatures

Active regeneration systems for cleaning diesel exhaust can operate at extremely high temperatures up to 1000 degrees C. The extremely high temperatures create a unique challenge for the design of regeneration structural components near their melting temperatures. In this paper, the preparation of the sheet specimens and the test set-up based on induction heating for sheet specimens are first presented. Tensile test data at room temperature, 500, 700, 900 and 1100 degrees C are then presented. The yield strength and tensile strength were observed to decrease with decreasing strain rate in tests conducted at 900 and 1100 degrees C but no strain rate dependence was observed in the elastic properties for tests conducted below 900 degrees C. The stress-life relations for under cyclic loading at 700 and 1100 degrees C with and without hold time are then investigated. The fatigue test data show that the hold time at the maximum stress strongly affects the stress-life relation at high temperatures. When the results are plotted as functions of the time to failure, the test data suggest that creep dominates the failure of the sheet specimens at elevated temperatures.