发电技术 ›› 2017, Vol. 38 ›› Issue (5): 35-38.DOI: 10.3969/J.ISSN.2095-3429.2017.05.008

• 发电技术 • 上一篇    下一篇

600MW超临界机组屏式过热器管爆管分析

白佳   

  1. 华电电力科学研究院, 浙江 杭州 310030
  • 收稿日期:2017-09-27 出版日期:2017-10-30 发布日期:2017-10-30
  • 作者简介:白佳(1984-),女,陕西榆林人,工学硕士,工程师,主要从事电站设备金属理化检验与失效分析方面的工作

Burst Analysis on Platen Superheater Tube of 600MW Supercritical Units

BAI Jia   

  1. Huadian Electric Power Research Institute, Hangzhou 310030, China
  • Received:2017-09-27 Published:2017-10-30 Online:2017-10-30

摘要: 通过对爆管样品的宏观形貌分析、化学成分分析、硬度检验、金相组织检验和扫描电镜分析,对某超临界机组T91材质的屏式过热器爆管原因进行分析。结果表明,爆管试样硬度偏低,这与显微组织的变化相关。T91钢的正常供货组织应为回火马氏体,而爆管样品爆口处的金相组织显示马氏体板条位向消失,演变为铁素体和于晶界处析出的颗粒较大的碳化物。屏式过热器管超温服役,导致材料组织老化,综合力学性能下降,在高温高压蒸汽作用下发生失效,造成泄漏。

关键词: 超临界锅炉, 屏式过热器, T91钢, 爆管

Abstract: The burst cause of a platen superheater tube of T91 steel in certain supercritical units was ana-lyzed by macroscopical morphology, chemical composition, hardness test,OM and SEM observation using the speci-mens exploded platen superheater tube.Results show a low hardness of the failed tube which is related to the micro-structure transformation.The metallographic structure of T91 steel is tempered martensite, while the metallographic struc-ture of the exploded tube doesn't show any martensite at all.The martensite lath is evolved into ferrite and coarsen carbides precipitated at grain boundry.The overheat opera-tion of superheater tube causes the microstructure degrada-tion and the decrease of mechanical properties, and finally causes the leakage of platen superheater tube under the condition of high temperature and pressure steam.

Key words: supercritical units, platen superheater tube, T91 steel, burst tube

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