Cyclic Plastic Deformation of Stainless Steel SUS 304 at Liquid Nitrogen Temperature under Constant Plastic Strain Range

Cyclic loading tests are performed on thin-wall tubes of SUS 304 stainless steel at low temperature of liquid nitrogen (77K) under constant plastic strain range. Cyclic Stress-strain curves for constant plastic strain range are experimentally investigated under tensile or torsional cyclic loading. Saturation properties of the cyclic stress-strain curves are examined by different plastic strain ranges of cyclic loading. Stress-strain curves are saturated with increase of cyclic number. A large plastic strain range of cyclic loading results in large plastic hardening. Ratchetting behavior is also experimentally investigated with torsional cyclic loading under different constant axial stresses. The rachet deformation depends on the constant axial stress. The rachet strains by torsional cyclic loading is produced even without the constant axial stress and is not produced under a certain compressive axial stress.