CAJ | 학술논문

通过宏观分析、化学组成分析、金相分析、扫描电镜分析等方法，对省煤器联箱接管座与管排焊接接头泄漏原因进行了分析。结果表明，焊接管化学成分、换算强度均符合 GB5310-2008标准要求。熔合区、过热区晶粒组织粗大，甚至形成魏氏组织，使这一区域性能弱化。省煤器联箱接管座与管排焊接接头穿孔是因应力作用下在熔合区、过热区薄弱处首先产生微裂纹，启裂后虽未形成贯穿裂纹，但微裂纹导致缝隙腐蚀，缝隙腐蚀加速裂纹由内向外深化和扩展直至穿孔，产生泄漏。
통과굉관분석、화학조성분석、금상분석、소묘전경분석등방법，대성매기련상접관좌여관배한접접두설루원인진행료분석。결과표명，한접관화학성분、환산강도균부합 GB5310-2008표준요구。용합구、과열구정립조직조대，심지형성위씨조직，사저일구역성능약화。성매기련상접관좌여관배한접접두천공시인응력작용하재용합구、과열구박약처수선산생미렬문，계렬후수미형성관천렬문，단미렬문도치봉극부식，봉극부식가속렬문유내향외심화화확전직지천공，산생설루。
Through macro-analysis, chemical composition analysis, metallographic observation, and SEM, the leakage reasons for joint of tube of header and coil tube of coal economizer was analyzed.The results show that the alloy element compositions of welded tubes and conversion strength both met the standard of GB 5310-2008.The grains at fusion zone and overheated zone were coarse and even formed widmanstaten structure which made the performance of the zone weaken.Leakage from the joint of tube of header and coil tube of coal economizer resulted in the micro cracks in the weakened region of fusion and overheated zone under the thermal stress.Though through-wall crack was not formed after micro cracks initiation,micro cracks resulted in crevice corrosion and the crevice corrosion accelerated crack propagation from the inside outwords,and eventually caused the leakage.