氢介质环境下高温管道蠕变损伤机理及预测模型研究

This project aims to study the creep damage mechanism and life prediction model of high temperature piping in hydrogen environment, which is the critical issue in the long term and safe operation of some key components in chemical energy industry. Covered tasks are: 1) Emphasis will be laid on the establishment of the damage constitutive model coupling creep and hydrogen attack, based on the creep tests under elevated temperature and hydrogen environments. This part can be adopted to describe the effects of high-temperature hydrogen environment on the creep damage of materials. 2) FEM method will be employed to simulate various forms of pipeline structures under elevated temperature and hydrogen environment. The numerical results will be applied to explain the damage mechanism and evolution under creep-hydrogen interaction. 3) The life prediction model of pipeline structures under the interactive environment will be established on the basis of understanding of chemo-mechanical effect. Interactive effects of mechanics, chemistry and material will be incorporated and considered in the present approach. From the chemo-mechanical perspective, this research will offer a better understanding of the damage mechanism of materials used in high temperature piping under hydrogen environment, and allow the development of the life prediction model for purpose of practical engineering application.

面向能源化工装备长周期安全运行的需求，开展高温临氢管道蠕变与氢蚀交互作用下的损伤机理及寿命预测模型的研究。主要包括：1）通过临氢环境下高温蠕变试验研究，找出氢致蠕变损伤加速的临界参数，澄清蠕变和氢蚀交互作用的损伤机理并构建材料损伤本构模型；2）通过对不同结构形式及载荷状态下的管道结构进行损伤分析，了解蠕变及氢损伤对管道结构强度的削弱及损伤演化规律，实现对高温临氢管道结构在复杂应力状态下失效模式的科学认识；3）在理解化学力学作用的基础上，进而建立高温临氢管道寿命预测模型。本项目体现了力学、化学和材料等多学科领域的交叉，可望从化学和力学角度获得高温临氢管道的损伤机理并建立寿命预测模型。

能源化工装备向着高温高压长寿命安全运行的方向发展，研究典型材料在极端环境下的破坏及损伤机理，提出安全评定方法，已成为迫切需要解决的问题。项目围绕过程装备中高温高压管道材料的损伤分析及氢在其中的作用问题，从试验研究、有限元模拟和理论建模三个层面，尝试解决长寿命氢腐蚀破坏的微观机理和损伤本构。项目结合损伤力学理论，将损伤与Ramberg-Osgood弹塑性本构方程耦合将造成蠕变损伤的因素综合考虑，根据微观组织观察分析及蠕变拉伸实验数据拟合，可以预测长期服役后的高温材料的弹塑性响应；结合试验研究和有限元模拟，指出了氢对奥氏体不锈钢相变的影响；进而通过超高周疲劳试验，揭示内部缺陷处疲劳破坏的本质，初步形成了氢对高温承压管道材料损伤机理的科学认识。本项目的研究内容和结果，基本揭示了项目拟解决的三个科学问题，达到了预期目标。研究结果体现了力学、物理和材料等多学科的交叉，为氢环境下的高温部件的损伤模式评定提供了新的思路，从而可为能源装备的损伤评定和寿命设计提供科学支持。