Characterization of Low Cycle Fatigue of Ferritic-Martensitic P92 Steel: Effect of Temperature

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• 作者：Xiaowei Wang ; Yong Jiang ; Jianming Gong ; Yanping Zhao and Xin Huang
• 刊名：steel research international
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：87
• 期：6
• 页码：761-771
• 全文大小：1265K
• ISSN：1869-344X

文摘

Isothermal, strain-controlled low cycle fatigue (LCF) tests of P92 steel are conducted in air at different temperatures ranging from 20 to 650 °C and various strain ranges to clarify the influence of temperature on its LCF behavior. A symmetrical triangular wave form and a constant 1.0 × 10⁻³ s⁻¹ strain rate are employed for all the tests. Cyclic softening behavior is expressed in two ways: peak tensile stress in terms of cycle numbers and in terms of accumulated inelastic strain. Based on the definition of “inelastic ratio,” correlation between the value of accumulated inelastic strain (line-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">ϵ¯in,II) at the beginning of the second softening stage and the inelastic ratio can be distinctively divided into three regions. The modified cyclic plasticity model, in which a linear term is added into the isotropic hardening variable, is developed to simulate the stress–strain hysteresis loop and the cyclic softening curve. Additionally, parameters in the modified isotropic hardening variable at different temperatures are correlated to the cyclic softening phenomenon. Performances of the modified model are assessed by comparing predictions with experimental results. Good predictive capability of the modified constitutive model is obtained.