Cyclic Plastic Deformation of Stainless Steel SUS304 Subsequent to Plastic and Creep Prestraining.

Abstract

Effects of plastic and creep prestrain on cyclic plastic deformation are experimentally investigated. Thin walled tubular specimens of stainless steel SUS304 are subjected to combined axial and torsional loads. Prestraining is conducted at room temperature and 600°C, and subsequent cyclic loading under constant strain amplitude is performed at room temperature and 600°C. The cyclic stress-strain curves become saturated with increasing number of cycles. The properties of cyclic loading are examined based on the maximum stress values of the saturated cyclic stress-strain curves. The saturated cyclic stress subsequent to creep straining is influenced by testing temperature as well as strain amplitude. Small strain amplitudes result in large saturated stress values comparing with cyclic loading without creep prestraining. The effects of cyclic loading under combined stress state are also examined using the equi-plastic strain curves. Tensile creep straining expands the equiplastic strain curves in the directions of tensile and torsional stresses. Cyclic loading subsequent to tensile creep straining result in the expansion of the equi-plastic strain curves in the directions of tensile and compressive stresses.