The Influence of Test Temperature on the Ratchetting Behavior of Type 304 Stainless Steel

Abstract

The zero-to-tension ratchetting behavior was investigated under uniaxial loading at room temperature and at 550, 600, and 650°C. In History I the maximum stress level of ratchetting was equal to the stress reached in a tensile test at one percent strain. For History II the maximum stress level was established as the stress reached after a 2100 s relaxation at one percent strain. Significant ratchetting was observed for History I at room temperature but not at the elevated temperatures. The accumulated ratchet strain increases with decreasing stress rate. Independent of the stress rates used insignificant ratchet strain was observed at room temperature for History II. This observation is explained in the context of the viscoplasticity theory based on overstress by the exhaustion of the viscous contribution to the stress during relaxation. The viscous part of the stress is the driving force for the ratchetting in History I. Strain aging is presumably responsible for the lack of short-time inelastic deformation resulting in a nearly rate-independent behavior at the elevated temperatures.

Uniaxial Ratchetting of 316FR Steel at Room Temperature— Part I: Experiments

“…It has already been reported that 304 and 316 stainless steels exhibit noticeable viscoplasticity at room temperature (e.g., Krempl, 1979;Kujawski et al, 1980;Chaboche and Rousselier, 1983;Yoshida 1990), so that ratchetting of such austenitic stainless steels at room temperature is affected much more actively by viscoplasticity than at high temperatures around 550°C where dynamic strain aging tends to suppress viscoplasticity (Ruggles and Krempl, 1989;Sasaki and Ishikawa, 1993;Delobelle, 1993). This suggests that the aforementioned finding on ratchetting of 316FR steel at high temperatures, i.e., almost complete closure of hysteresis loops and isotropic hardening depending on maximum plastic strain, may not hold true at room temperature.…”

Influence of testing mode on the fatigue behavior of <111> austenitic grain at the nanometric length scale for TRIP steels

“…In the indentation tests performed under loading control mode the second and third cycles are open, a fact which may be related to the time-dependent plasticity exhibited which is known to occur in austenitic steels. This phenomenon, extensively investigated [16][17][18][19][20][21][22][23], is related to the accumulation strain generated during the cyclic indentation process, also known as ratcheting effect. The latter is not observed in tests performed under displacement control.…”

Uniaxial Ratchetting Behavior of Solder Alloys and Its Simulation by an Elasto-Plastic-Creep Constitutive Model

“…1 However, details of ratchetting deformation are not well understood experimentally or theoretically, although there is much research on the subject. [1][2][3][4][17][18][19][20] Ratchetting deformation of steels such as stainless steels has been actively investigated by many researchers from about three decades ago due to problems in nuclear systems. Ruggles and Krempl, 1 for example, conducted experimental observations of the uniaxial ratchetting behavior of type 304 stainless steel.…”

“…[1][2][3][4][17][18][19][20] Ratchetting deformation of steels such as stainless steels has been actively investigated by many researchers from about three decades ago due to problems in nuclear systems. Ruggles and Krempl, 1 for example, conducted experimental observations of the uniaxial ratchetting behavior of type 304 stainless steel. The authors have also studied the uniaxial and biaxial ratchetting behavior of type 304 stainless steel with simulation by a viscoplastic constitutive model employing a Prager-Zieglartype hardening rule, [2][3][4] and have shown that the ratchetting deformation correlates closely with the time-dependent deformation.…”