某部一台1996年生产的DZL4—1.25—A2锅炉,在1998年锅炉检验时发现该炉左侧前数第2、3、5根,右侧前数第1、2、5根共6根水冷壁管背火侧煨弯处腐蚀泄漏。后经割管分析,其它水冷壁管背火侧煨弯处水侧腐蚀减薄严重,内壁腐蚀坑深达2.7mm,有的腐蚀坑处剩余壁厚仅0.2mm。对该炉水冷壁管进行化学成分,分析结果合格。微观金相分析表明,其微观金相组织为铁素体+珠光体,晶粒度为8级,无脱碳和球化现象。材料的抗拉强度合格,无明显的屈服点,材料的延伸率为12.3%,低于国家标准18%。该炉采用Na~+水处 A certain unit of DZL4-1.25-A2 boiler produced in 1996 found that in the boiler inspection in 1998, the first two, the first, the second, the fifth and the fifth on the left of the furnace were 6 Water wall tube simmer on the fire side corrosion corrosion leak. After the pipe cutting analysis, the water side of the other side wall of the water-cooled pipe simmering bend water side of serious erosion, corrosion pit depth of up to 2.7mm, and some corrosion pits at the remaining wall thickness of only 0.2mm. The boiler water wall tube chemical composition, analysis of qualified. Micro-metallographic analysis shows that the microstructure of the microstructure is ferrite + pearlite with a grain size of 8 grades, without decarburization and spheroidization. Tensile strength of the material is qualified, no obvious yield point, the material elongation of 12.3%, 18% lower than the national standard. The furnace Na ~ + water