A physics-based life prediction model of HP40Nb heat-resistant alloy in a coupled creep-carburisation environment
A physics-based life prediction model of HP40Nb heat-resistant alloy in a coupled creep-carburisation environment
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DOI：
10.1016/j.msea.2022.144260
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
Chen Fuyang;J. Gong;Xiaowei Wang;C. Panwisawas;Bo Chen
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文献类型：
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作者：
Chen Fuyang;J. Gong;Xiaowei Wang;C. Panwisawas;Bo Chen
本文报道了一个基于物理学的寿命预测模型，它包括三个微观损伤过程的发展。使用扫描电子显微镜测定的颗粒面积分数和尺寸均用作模型输入来预测沉淀物粗化损伤。此外，使用电子探针显微分析仪测量的碳浓度分布被用于导出渗碳损伤分布指数。与Kowalewski-Dyson模型相比，本模型能较好地预测蠕变断裂应变和断裂时间。该模型通过用户子程序编译成有限元模型，可以预测HP40 Nb合金裂解炉管在蠕变-渗碳耦合环境中的非均匀损伤累积。预测的总损伤是由沉淀粗化和渗碳为主导，而蠕变空蚀贡献少得多，由于低的内压。沉淀物粗化的分布在整个厚度上是相对均匀的，而渗碳导致靠近内表面的损伤值急剧增加。就时间而言，沉淀粗化损伤在初始阶段占主导地位，而总的损伤由渗碳过程与进一步曝光。最终，在59600 h时，总损伤达到临界值，渗碳层厚度超过管厚的50%，管子内表面失效，与运行经验一致。参数敏感性研究揭示了确定富铬碳化物面积分数的寿命预测的重要性。
This paper reports the development of a physics-based life prediction model that incorporates three micro-damage processes. Both the particle area fraction and size, as determined using scanning electron microscopy, are used as the model input to predict the precipitate coarsening damage. Moreover, the carbon concentration profile, as measured using electron probe micro-analyser, are used to derive the carburisation damage distribution index. Compared to the Kowalewski-Dyson model, the present model can predict the stress dependent creep fracture strain and rupture time. The model, compiled into finite element via the user subroutine, can predict the heterogeneous damage accumulation of the cracking furnace tube made of HP40Nb alloy in a coupled creep-carburisation environment. The predicted total damage is comprised of precipitate coarsening and carburisation as the predominance, while the creep cavitation contributing much less due to the low internal pressure. The distribution of the precipitate coarsening is relatively homogeneous through the thickness, whereas the carburisation causes a steep increased damage value close to the inner surface. With regard to time, the precipitate coarsening damage is predominant in the initial stage, while the total damage is governed by the carburisation process with further exposure. Eventually, the total damage reaches the critical value at 59600 h, with the thickness of carburised layer exceeding 50% of the tube thickness, and the tube fails in the inner surface which agrees with the operational experience. The parametric sensitivity study reveals the importance of determining the Cr-rich carbide area fraction for the life prediction.