Uniaxial cyclic ratcheting and plastic flow properties of SS304 stainless steel at room and elevated temperatures

An experimental study was carried out for the uniaxial ratcheting of SS304 stainless steel subjected to cyclic stress at room and elevated temperatures. The effects of stress amplitude, mean stress and their histories on the ratcheting of SS304 stainless steel were analyzed at room and elevated temperatures. The interaction of uniaxial strain cycling and stress cycling was also discussed at variable temperatures. On the basis of the experimental data under uniaxial strain and stress cycling, the plastic flow properties of the material were analyzed. The evolution rules of plastic modulus vs. accumulated plastic strain during cyclic loading were investigated under the condition of variable loading processes. The discussion was focused on the relation of uniaxial ratcheting rate and such plastic flow properties as plastic modulus and accumulated plastic strain. It is shown that the uniaxial cyclic properties of the material depend not only on the current loading case and temperature, but also greatly on the previous loading history. The plastic flow properties of strain cycling are apparently different from those of asymmetrical stress cycling; the ratcheting of asymmetrical stress cycling at room and elevated temperature is greatly influenced by the evolution of plastic modulus and accumulated plastic strain. These conclusions are very useful to the development of constitutive model for ratcheting.