离心压缩机叶轮材料在掺氢天然气环境下的氢相容性

Hydrogen Compatibility of Centrifugal Compressor Impeller Material in Hydrogen-Blended Natural Gas Environment

摘要:

通过慢应变速率拉伸试验、疲劳裂纹扩展试验及断裂韧性试验初步评估了离心压缩机叶轮材料FV520B钢在不同掺氢天然气环境下的氢相容性，并结合断口整体形貌、微观结构特征进行分析。结果表明，掺氢比和气体压力升高，FV520B钢的抗拉强度和屈服强度相对空气环境均出现不同程度下降，同时断后伸长率和断面收缩率也明显下降，出现氢致塑性损失现象；掺氢比和气体压力升高，裂纹扩展速率-应力强度因子范围曲线整体左移，试样更早地发生裂纹扩展以及更快地进入失稳断裂，且其断裂韧性K_IC值降低，低倍断口形貌也观察到材料有变脆的倾向。本研究结果为离心压缩机叶轮材料FV520B钢在掺氢天然气运输中的工程应用提供了重要的实验参考。

Abstract:

The hydrogen compatibility of FV520B steel immersed in different hydrogen-blended natural gas environments was evaluated through slow strain-rate tensile testing, fatigue crack propagation testing, and fracture toughness testing and fracture morphology and microstructural characteristic were analyzed. The results show that as the hydrogen blending ratio and gas pressure increase, both the tensile strength and yield strength of FV520B steel decrease in different degrees, and the elongation after fracture and the reduction of area also decrease, demonstrating hydrogen induced plastic loss phenomenon. With increasing hydrogen content and gas pressure, the crack growth rate-stress intensity factor range curves shift left, leading to earlier crack propagation and faster entry into unstable fracture of the sample. Meanwhile, the fracture toughness K_IC value of FV520B steel decreases, and a tendency towards brittleness is observed in the low magnification fracture morphology of the material. The present study provides an important basis for evaluating the engineering application of centrifugal compressor impeller materials during transport of hydrogen-blended natural gas.