深冷处理对CF8M不锈钢微观组织和显微硬度的影响

Effect of Cryogenic Treatment on the Microstructure and Microhardness of CF8M Stainless Steel

  • 摘要: 本文针对CF8M不锈钢在-196℃深冷处理前后的微观组织演变及显微硬度变化进行了系统研究,旨在为高新船舶和民用船舶的高压密封件和低温阀门等关键部件的材料优化提供理论依据和技术支持。通过金相显微镜观察、显微硬度测试和纳米压痕测试等手段,分析了深冷处理对材料相组成、组织形貌及力学性能的影响。研究结果表明,深冷处理显著改变了CF8M不锈钢的金相组织:原先弥散分布的铁素体由块状、网状向条状或针状转变,组织致密性和取向性明显增强,同时部分残余奥氏体发生了向马氏体的转变。这些微观结构的转变使材料的局部硬度提高,硬度分布更为均匀。纳米压痕试验显示,在相同载荷下,深冷处理后的样品压入深度明显减小,反映出更高的抗塑性变形能力及弹性模量。本文的研究为CF8M不锈钢在极端低温工况下深冷处理工艺工程化应用提供了实验数据和理论支持。

     

    Abstract: This study explores the microstructural evolution and microhardness changes of CF8M stainless steel before and after cryogenic treatment at -196°C, providing theoretical and technical support for optimizing materials in high-pressure seals and low-temperature valves for high-tech and commercial ships. Metallographic analysis, microhardness testing, and nanoindentation were used to assess phase composition, microstructure, and mechanical properties. Results show that cryogenic treatment refines the ferrite morphology from blocky and network-like to lamellar or acicular, enhancing structural compactness and orientation. Partial residual austenite transforms into martensite, leading to increased local hardness and a more uniform distribution. Nanoindentation tests indicate reduced indentation depth post-treatment, reflecting improved plastic deformation resistance and higher elastic modulus. This study offers experimental and theoretical insights for enhancing CF8M stainless steel’s cryogenic performance, advancing material design for extreme environments.

     

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