RATCHETTING CHARACTERISTICS OF 316FR STEEL AT HIGH-TEMPERATURE, PART-I - STRAIN-CONTROLLED RATCHETTING EXPERIMENTS AND SIMULATIONS

The paper is concerned with characteristics in ratchetting of 316FR st eel at high temperature. In Part I, first, by discussing isothermal an d nonisothermal ''strain-controlled'' ratchetting experiments, it is s hown that 316FR steel exhibits the almost perfect closure of stress an d strain hysteresis loops as well as the isotropic hardening depending on maximum plastic strain rather than accumulated plastic strain. Sec ond, it is demonstrated that the experiments are simulated well using the nonlinear kinematic hardening model proposed in 1993 by Ohno and W ang (Int. J. Plasticity 9, 375-403) if the model is extended by taking account of the isotropic hardening depending on maximum plastic strai n. On the basis of these findings, thermal ratchetting of 316FR steel cylinders subjected to the axial variation of temperature is analyzed in Part II. (C) 1998 Elsevier Science Ltd. All rights reserved.