Temperature-Dependence of Multiaxial Non-Proportional Cyclic Behavior of Type 316 Stainless Steel

Temperature dependence of multiaxial cyclic behavior of type 316 stainless steel was elucidated experimentally. Cyclic tests under constant total-strain amplitudes were performed for uniaxial tension-compression and circular (non-proportional) strain paths at several temperatures; room temperature, 200°C, 400°C, 500°C, 600°C, and 700°C. The strain amplitudes of the cycles were specified to be 0.2, 0.3, and 0.4 percent under constant strain rate of 0.2 percent per min. A quantitative discussion was made with special emphasis on the difference between material behavior under uniaxial tension-compression strain cycles and multiaxial non-proportional circular ones at these temperatures. The most significant cyclic hardening was observed in the temperature range between 400°C and 600°C for both the proportional and the non-proportional strain cycles. At these particular temperatures, much larger inelastic strain was accumulated until a cyclic stabilization was obtained. Though the effect of non-proportionality in the cyclic strain paths on the cyclic hardening was significant particularly at the temperature below 450°C, it rapdily decreased at higher temperatures.