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9Cr钢焊接接头蠕变失效机制及服役寿命提升研究进展

Research progress on creep failure mechanisms and service life enhancement of 9Cr steel welded joints

  • 摘要: 9Cr耐热钢是火电和核电高温蒸气部件的关键材料,其焊接接头长期服役过程中普遍面临IV型蠕变开裂问题,显著降低了装置服役寿命,抑制IV型蠕变开裂以延长蠕变寿命对9Cr耐热钢的安全应用至关重要. 基于国内外相关研究,系统梳理了蠕变敏感区在焊接和焊后热处理过程中微观组织演变规律,总结了9Cr耐热钢焊接接头蠕变开裂机理的研究现状. 结果表明,焊接接头中原奥氏体晶粒尺寸与析出相特性是决定其蠕变性能的微观组织关键因素. 基于此,从母材合金元素调控、初始微观组织设计、焊接工艺优化以及焊后热处理策略调整等方面,系统阐述了提升9Cr耐热钢焊接接头蠕变寿命的研究进展,最后展望了未来的研究方向.

     

    Abstract: 9Cr heat-resistant steel is a critical material for high-temperature steam components in thermal and nuclear power plants. Its welded joints generally face Type IV creep cracking during long-term service, significantly reducing the device service life. Suppressing Type IV creep cracking to extend creep life is crucial for the safe application of 9Cr heat-resistant steel. Based on Chinese and international related research, the microstructural evolution rules of creep-susceptible zones during welding and post-weld heat treatment were systematically outlined, and the research status of creep cracking mechanisms of 9Cr heat-resistant steel welded joints was summarized. The results indicate that the prior austenite grain size and precipitate characteristics in the welded joints are key microstructural factors determining their creep properties. Based on this, the research progress on enhancing the creep life of 9Cr heat-resistant steel welded joints was systematically expounded from the aspects of base metal alloying element regulation, initial microstructure design, welding process optimization, and post-weld heat treatment strategy adjustment. Finally, future research directions were prospected.

     

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