在短时间的服务后,P91蒸汽管肘部的爬行寿命显著减少,这是由于异常的微观结构造成的
Hongyu Zhou1,2, Jian Li3, Jie Liu4
1National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing, 100083, China. hyzhou@ustb.edu.cn.
Scientific reports
|March 3, 2024
概括
由于微观结构的退化,P91钢主要蒸汽管的肘部经历了过早的故障. 这大大缩短了它们的使用寿命,强调了电厂需要仔细监控的必要性.
科学领域:
- 材料科学 材料科学 材料科学
- 金工业是金工业的一个方面.
- 电力工程 电力工程
背景情况:
- 对于超超临界的发电厂蒸汽管道而言,P91钢是至关重要的,它被设计用于10万小时.
- 一个主要的蒸汽管道肘部显示,仅经过20,000小时的服务后,爬行破裂寿命大幅减少.
研究的目的:
- 调查P91钢主蒸汽管肘部过早故障的原因.
- 分析微观结构的变化及其对爬行动物的影响.
- 评估退化元件的剩余使用寿命.
主要方法:
- 失败的P91钢肘的微结构分析.
- 在高温 (550-600 °C) 和应力 (85-140 MPa) 下对P91钢进行滑动测试.
- 拉森-米勒参数分析用于剩余寿命预测.
主要成果:
- 微观结构揭示了马氏石的分解,M23C6碳化物和拉维斯相积累,以及铁块的形成.
- 降解导致硬度降低到ASME标准以下.
- 洞穴形成和裂更多地受到温度的影响,而不是压力.
- 破裂寿命比预期缩短了两个数量级,原因是亚粒生长和碳化/岩阶段粗.
- 预计其余寿命为53,353小时,远远低于设计寿命.
结论:
- 微结构性降解,包括碳化物和拉维斯相粗化,导致P91钢肘部过早故障.
- 温度在腔腔形成和裂中起到的作用比压力更为重要.
- 由于剩余寿命缩短,因此需要在未来服务期间更加关注该部件的安全性和监控.
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