考虑高温蠕变损伤的服役金属屈服强度模型探析

RESEARCH ON YIELD STRENGTH MODEL OF SERVICE METAL CONSIDERING HIGH TEMPERATURE CREEP DAMAGE

  • 摘要: 在役设备长期承受高温高压且无法预测其重要力学性能指标,有必要建立考虑高温蠕变损伤的屈服强度模型。传统屈服准则未考虑温度的影响以及材料有效杨氏模量随损伤下降的趋势。在阐述金属温度相关性屈服强度理论模型和K-R蠕变损伤本构方程的基础上,通过建立服役杨氏模量与蠕变损伤内变量的内在联系,推导出考虑高温蠕变损伤的服役金属屈服强度模型。以SA508-III钢材料为例,开展了蠕变中断+高温拉伸试验,理论计算与试验结果呈现一致性。

     

    Abstract: In-service equipment is subjected to high temperature and high pressure for a long time and its important mechanical properties cannot be predicted. It is necessary to establish a yield strength model considering high temperature creep damage. The traditional yield criterion ignores the characteristics of temperature influence and the decreasing trend of effective Young 's modulus with damage accumulation. The theoretical model of metal temperature dependent yield strength and the K-R creep damage constitutive equation are introduced. On this basis, the internal relationship between the service Young's modulus and the internal variable of creep damage is established, and the yield strength model of service metal considering high temperature creep damage is derived. The creep interruption combined high temperature tensile test was conducted on SA508-III steel material, and the theoretical calculation was consistent with the test results.

     

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