UNIAXIAL TIME-DEPENDENT RATCHETING BEHAVIORS OF 1CR18NI9 STAINLESS STEEL AT ELEVATED TEMPERATURES

The uniaxial cyclic straining characteristics and time-dependent ratcheting behavior of 1Cr18Ni9 stainless steel were studied experimentally at room temperature, 250℃, 500℃ and 650℃, to investigate the dependence of the ratcheting upon loading rates，loading wave forms and peak stress holding times. The experimental results show that at room temperature, the material presents weak cyclic softening and its ratcheting behavior is strongly affected by the loading rate and hold-time; at 250℃ and 650℃, the ratcheting behavior of the material shakes down quickly due to the cyclic strain hardening, whereas the magnitudes of the ratcheting strain is still dependent on the loading rate and hold-time to some extent; at 500℃, no ratcheting occurs due to the effect of dynamic strain aging. Some conclusions obtained are useful for the construction of a sound constitutive equation.