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某化工厂锅炉蒸发器吊挂管在运行了5年后突然发生爆裂失效。对该吊挂管进行了化学成分分析、金相检验、扫描电镜、X射线衍射分析及力学性能测定,结果表明:吊挂管爆口附近的碳含量和力学性能均低于相关标准规定值;管外壁脱碳;内部金相组织为过热组织。这些都是由于管内壁沉积有钙盐和硅酸盐类水垢,造成管体超温运行的结果。严重沉积的水垢还导致管内壁高温氢腐蚀,壁厚由原来的6mm减至2～3mm,因此发生了失效爆裂。根据分析结果提出了相应的解决方案。
A chemical plant boiler evaporator hanging tube suddenly burst after 5 years of operation failure. The chemical composition analysis, metallographic examination, scanning electron microscopy, X-ray diffraction analysis and mechanical properties of the pipe were carried out. The results show that the carbon content and mechanical properties of the pipe near the mouth of the pipe are lower than the relevant standards; Tube decarburization; internal microstructure is overheating. These are due to the tube wall deposition of calcium and silicate scale, resulting in the results of over-temperature tube operation. Severe deposition of scale also led to high temperature hydrogen corrosion tube wall, the wall thickness reduced from 6mm to 2 ~ 3mm, so the failure occurred burst. According to the analysis results put forward the corresponding solutions.