Effects of Unloading on Subsequent Yielding Behavior in 304 Stainless Steel

Forming operations are known to be complex, involving many strain states, rates, temperatures, paths, and friction conditions. Material properties, such as strength ductility, large drivers in determining if a material can formed into specific part, for selecting the equipment required forming operation. Predicting yielding behavior situations these has been done using yield surfaces describe stress states. These models typically use initial mechanical will require correction experienced previous straining. Here, we performed interrupted uniaxial tensile testing of 304 stainless steel observe effects unloading subsequent reloading on properties. An increase point developed, which higher was observed prior returning bulk work hardening behavior, magnitude varied with conditions imposed. The appearance is attributed aging or dislocation trapping at obstacles within matrix. results suggest that both mechanisms may active matrix, present challenges when austenitic new advanced high steels likely show similar behavior. provide potential area refinement calculation criteria currently used predict