Thermal ratcheting of a P91 steel cylinder under an axial moving temperature distribution
Thermal ratcheting of a P91 steel cylinder under an axial moving temperature distribution
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轴向移动温度分布下 P91 钢筒的热棘轮
DOI：
10.1016/j.jnucmat.2016.01.028
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发表时间：
2016
影响因子：
3.1
通讯作者：
G. Giannuzzi
中科院分区：
文献类型：
--
作者：
M. Angiolini;G. Aiello;P. Matheron;L. Pilloni;G. Giannuzzi
渐进的非弹性变形，通常称为棘轮效应，是在塑性范围内承受机械和热循环载荷的部件和结构设计中的主要问题。在RCC-MRx规范中，通过应用基于结构弹性分析的简化方法来进行棘轮效应的设计评估。设计规则使用一个图，称为效率图，阐述基本上是基于拉伸/扭转实验的结果。在这项工作中，RCC-MRx效率图的应用P91钢进行了研究。研究了无主应力作用下受轴向温度梯度作用的圆柱体的热棘轮效应。热负荷已通过热液体热冲击产生，通过浸渍在熔融的共晶混合物的硝酸钠和硝酸钾的圆柱形模型。实验结果表明，RCC-MRx中现有的效率图不适用于P91钢。将其用于设计将预见到累积应变低于实验观察到的应变，这显然是不保守的。这一结果证实了在以前的拉伸-扭转棘轮试验中获得的结果，并为开发适用于9 Cr钢的改进的效率图提供了额外的数据。
The progressive inelastic deformation, commonly referred as ratchetting, is a major concern in the design of components and structures submitted to mechanical and thermal cyclic loads in the plastic range. In the RCC-MRx code, the design assessment against ratcheting is performed by applying a simplified method based on the elastic analysis of the structure. The design rule uses a diagram, called efficiency diagram, elaborated essentially on the basis of the results of tension/torsion experiments.In this work the application of the RCC-MRx efficiency diagram to P91 steel has been investigated. It has been considered the thermal ratcheting of a cylinder subjected to a moving axial temperature gradient with no primary stresses applied. The thermal loads have been produced via hot liquid thermal shocks, by dipping a cylindrical mock-up in a molten eutectic mixture of sodium and potassium nitrates. The experimental results show that the present efficiency diagram in RCC-MRx is not suited for P91 steel. Its use for the design would foresee cumulative strains lower than those observed experimentally which is clearly not conservative. This result confirms the results obtained in previous tension-torsion ratcheting tests and provides additional data for the development of a modified efficiency diagram suited for 9Cr steel.