火电锅炉疏水管角焊缝断裂原因分析  

Cause Analysis on the Fracture of Fillet Weld of Drain Pipe in Thermal Power Boiler

作　　者：滕志勇 马芹征 刘献良 Teng Zhiyong;Ma Qinzheng;Liu Xianliang(Guoneng Inner Mongolia Hulunbuir Power Generation Co.,Ltd.,Hulunbuir,Inner Mongolia 021025,China;Suzhou Nuclear Power Research Institute Co.,Ltd.,Suzhou,Jiangsu 215004,China)

机构地区：[1]国能内蒙古呼伦贝尔发电有限公司,内蒙古呼伦贝尔021025 [2]苏州热工研究院有限公司,江苏苏州215004

出　　处：《机电工程技术》2023年第8期295-298,共4页Mechanical & Electrical Engineering Technology

摘　　要：针对某火电锅炉导汽管下方连接的疏水管角焊缝断裂的问题,对疏水管和焊缝区域取样进行了化学成分分析、能谱分析、金相检验、硬度测试和断口微观分析等试验,最终得出了角焊缝断裂的性质和原因。结果表明:疏水管化学成分符合ASME SA-213标准规定,焊缝断裂与疏水管母材无关;焊材使用与设计相符,焊缝硬度也未见明显异常,但不能排除是否存在焊缝外观不当、焊层金属厚度不足的问题;断口附近组织中存在较多的蠕变孔洞和微裂纹,与蠕变断口特征相符。综合分析得知,焊缝断裂性质为蠕变断裂,引起其断裂的原因为高温长时间运行下,焊缝区域受到较高的应力,加之焊缝区域整体强度不足,导致焊缝区域形成蠕变孔洞及微裂纹,裂纹扩展最终引起了焊缝蠕变断裂。In view of the problem of fillet weld fracture of drain pipe connected below the steam conduit of a thermal power boiler,the chemical composition analysis,energy spectrum analysis,metallographic inspection,hardness test and microscopic analysis of fracture surface are conducted on the drain pipe and weld area samples,and the property and cause of the fillet weld fracture are obtained.The results show that the chemical composition of the drain pipe meets the ASME SA-213 standard,and the weld fracture is independent of the train pipe;the use of welding consumables is consistent with the design,and there is no obvious abnormality in the hardness of the weld,but it cannot be ruled out whether there are problems of improper appearance of the weld and insufficient metal thickness of the weld layer;there are more creep holes and microcracks in the metallographic organization near the fracture,which is consistent with the creep fracture characteristics.Comprehensive analysis knows that the fracture property of the weld is creep fracture,the reason for the fracture is that the weld area is subject to high stress under high temperature and long time operation.In addition,the overall strength of the weld area is insufficient,resulting in the formation of creep holes and microcracks in the weld area,the crack propagation finally causes the weld creep fracture.

关 键 词：疏水管 T91 12Cr2Mo 沿晶裂纹 蠕变断裂 

分 类 号：TB31[一般工业技术—材料科学与工程]