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将经表面喷丸处理和未处理的TP304H钢管安装于锅炉再热器的高温段运行7474 h后,对内壁氧化膜进行形貌观察、能谱分析和X射线衍射分析。结果表明,喷丸处理可大幅度提高TP304H钢的抗水蒸汽氧化性能,氧化膜的生长速率显著降低且氧化膜的粘附性提高。显微分析表明,氧化膜由双层结构转变为单一高Cr氧化膜层,外层Fe的氧化层消失。分析认为喷丸在管子内壁产生的剧烈形变引起晶粒细化和马氏体相变,在高温下促进了Cr向表面扩散及生成富Cr的氧化层。
The surface peening and untreated TP304H steel tube was installed in the high temperature section of the boiler reheater 7474 h after operation, the inner wall oxide film morphology, energy spectrum analysis and X-ray diffraction analysis. The results show that shot peening can greatly improve the water vapor oxidation resistance of TP304H steel, the growth rate of the oxide film is significantly reduced and the adhesion of the oxide film is improved. Microscopic analysis shows that the oxide film changes from a double-layered structure to a single high-Cr oxide film, and the oxide layer of the outer layer disappears. It is considered that the severe deformation caused by shot peening on the inner wall of the tube causes grain refinement and martensitic transformation, which promotes the diffusion of Cr to the surface and the formation of Cr-rich oxide layer under high temperature.