1 000 MW机组锅炉水冷壁焊接接头失效分析

doi:10.3969/j.issn.1008-0198.2024.04.020

湖南电力 ›› 2024, Vol. 44 ›› Issue (4): 138-142.doi: 10.3969/j.issn.1008-0198.2024.04.020

• 故障与分析 • 上一篇

1 000 MW机组锅炉水冷壁焊接接头失效分析

龙会国, 景雪潮, 谢阿萌

国网湖南省电力有限公司电力科学研究院,湖南长沙 410208

收稿日期:2024-03-26 修回日期:2024-05-13 出版日期:2024-08-25 发布日期:2024-09-09
通信作者: 龙会国(1978),男,正高级工程师,主要从事材料检验检测、失效分析及焊接等研究工作。
基金资助:
国网湖南省电力有限公司科技项目(5216A5220025)

Failure Analysis of Welded Joints on Water Wall in 1 000 MW Ultra Supercritical Units

LONG Huiguo, JING Xuechao, XIE Ameng

State Grid Hunan Electric Power Company Limited Research Institute,Changsha 410208,China

Received:2024-03-26 Revised:2024-05-13 Online:2024-08-25 Published:2024-09-09

摘要/Abstract

摘要： 通过观察并分析裂纹宏观和微观形态、金相、硬度、扫描电镜、能谱及接头结构,研究了1 000 MW超超临界机组锅炉水冷壁安装焊缝裂纹失效原因。结果表明:焊缝根部间隙、焊缝根部凸出及其硬度超标;焊缝组织粗大及低熔点碳化物相偏析,弱化晶界;焊缝存在微裂纹,根据焊缝内部微裂纹氧化物相分析可确定为焊接热裂纹。在运行高温高压应力作用下,裂纹扩展最终导致开裂失效,焊接热裂纹是造成接头失效的主要原因。

关键词: 15CrMoG钢, 水冷壁, 焊接接头, 晶间裂纹, 热裂纹

Abstract: By observing the macroscopic and microscopic morphology of cracks,metallography,hardness,scanning electron microscopy, energy spectrum, and joint structure analysis, the failure reasons of welding seam cracks in the installation of the water-cooled wall of a 1 000 MW ultra supercritical unit boiler are studied. The results show that the gap at the root of the weld, the protrusion at the root of the weld, and their hardness exceed the standard, coarse weld microstructure and low melting point carbide phase segregation, weaken grain boundaries, and there are microcracks in the weld seam, which can be determined as welding hot cracks based on the analysis of the oxide phase inside the microcracks. Under the action of high temperature and high pressure stress during operation, crack propagation ultimately leads to cracking failure, and welding hot cracks are the main cause of this failure.

Key words: 15CrMoG steel, water wall tubes steel, butt welds, intergranular crack, hot crack

中图分类号:

龙会国, 景雪潮, 谢阿萌. 1 000 MW机组锅炉水冷壁焊接接头失效分析[J]. 湖南电力, 2024, 44(4): 138-142.

LONG Huiguo, JING Xuechao, XIE Ameng. Failure Analysis of Welded Joints on Water Wall in 1 000 MW Ultra Supercritical Units[J]. Hunan Electric Power, 2024, 44(4): 138-142.

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1 000 MW机组锅炉水冷壁焊接接头失效分析

Failure Analysis of Welded Joints on Water Wall in 1 000 MW Ultra Supercritical Units

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