Modeling of Temperature Dependence of Ratchetting Deformation Behavior of Modified 9Cr-1Mo Steel
Masatsugu YAGUCHI and Yukio TAKAHASHI
Abstract:The previous inelastic constitutive model developed by the authors for modified 9Cr-1Mo steel at 550oC was extended to apply to ratchetting deformation analysis in the temperature range between 200oC and 600oC. A kinematic hardening rule was changed from OW‡T to OW‡V model to improve accuracy of prediction of ratchetting deformation at lower temperatures, and evolutionary laws for cycle dependent variables were also modified to express cyclic hardening behavior observed at lower temperatures. Constants involved in the constitutive model were determined for each temperature based on the results of monotonic and cyclic loading tests. The extended constitutive model was applied to simulations of inelastic behavior under various loading conditions, including isothermal and anisothermal cyclic deformation and ratchetting deformation. It was demonstrated that the extended constitutive model is able to describe not only the ratchetting behavior but also the other inelastic behaviors including the anisothermal cyclic deformation with good accuracy. Key Words:Ratchetting deformation behavior, Inelastic constitutive model, Modified 9Cr-1Mo steel, Ohno-Wang model, Anisothermal cyclic deformation