锅炉水冷壁管爆管原因分析

Failure Analysis of Bursted Water Screen Tubes of Boiler

采用宏观检验、力学性能检测、金相检验、扫描电镜检查和X射线衍射分析等方法对某锅炉水冷壁管发生爆管的原因进行了分析。结果表明:水冷壁管爆裂是由于酸泄漏事故引起的,泄漏导致接触烟气侧的管内壁存在较多细小的微裂纹,使材料的拉伸强度和屈服强度大幅降低,加上锅炉水系统漏入酸溶液引起了氢腐蚀,最终导致水冷壁管在工作应力下发生氢脆断裂。

A failure accident of water screen tubes of boiler had been analyzed. Visual examination, mechanical test, metallographic examination, electron scanning microscope examination, X-ray diffraction examination had been used for this analysis. Lots of fine-cracks had been found on the inside wall of water screen tubes towards the fume. Deeply decrease of tensile strength and yield strength had been found when the water screen tubes towards the fume. The PH value of this boiler＇s water system was out of control as acidic property, which was caused by a mistake of operation in the past time. Hydrogen brittle fracture had been confirmed as the reason of the fracture of water screen tubes.