The alteration of material tensile properties is inevitable after material subjects to irreversible damage. This paper is devoted to quantify the influence of pre-fatigue damage on the residual tensile properties of P92 steel. Various pre-fatigue tests followed by uniaxial tensile tests are conducted at 650 °C. Results indicate that higher strain amplitude of pre-fatigue loading leads to reduction in residual yield stress and ultimate tensile stress (UTS). In addition, the evolution of yield stress and UTS in terms of pre-fatigue lifetime fraction shows two stages, namely initial rapid degradation stage and linear decreasing stage. The microstructure observation manifests that the growth of martensite lath width and the decline of dislocation density during pre-fatigue loadings contribute to the degradation of subsequent tensile strength. However, the reduction in dislocation density plays a dominant role. Furthermore, a pre-fatigue damage definition is proposed. The variations of residual yield stress and UTS can be described linearly with respect to the defined pre-fatigue damage. The newly proposed linear relationships are convenient for practical application.

材料遭受不可逆转的损坏后，材料抗拉性能的改变是不可避免的。本文致力于量化疲劳前损伤对P92钢残余拉伸性能的影响。在650°C下进行各种疲劳前测试，然后进行单轴拉伸测试。结果表明，较高的疲劳前应变幅度会导致残余屈服应力和极限拉伸应力（UTS）降低。此外，屈服应力和UTS在疲劳前寿命分数方面的演变表现出两个阶段，即初始快速降解阶段和线性下降阶段。显微组织观察表明，在疲劳前加载过程中，马氏体板条宽度的增长和位错密度的下降有助于随后的拉伸强度的降低。然而，位错密度的降低起主要作用。此外，提出了疲劳前损伤的定义。残余屈服应力和UTS的变化可以相对于定义的疲劳前损伤进行线性描述。新提出的线性关系为实际应用提供了方便。