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从腐蚀理论和影响因素来解释了“蒸汽发生器炉管失效分析”一文中所揭示的现象 ,蒸汽发生器炉管减薄主要源于内表面腐蚀 ,炉管径向截面出现裂纹和次生裂纹 ,腐蚀表面有冲蚀和气蚀痕迹。介绍了蒸汽发生器炉管壁减薄机理 ,炉管壁在高温高压的工况下 ,金属与水汽接触产生汽水腐蚀 ,形成以氧化铁为主的腐蚀产物。炉管内液体在流动过程中地被加热 ,产生大量的蒸汽泡 ,蒸汽泡溃灭过程中造成氧化膜甚至母体金属破坏。与此同时 ,应力和活性阴离子对氧化膜的破坏造成孔蚀 ;氧的存在加剧了腐蚀作用。气蚀作用能使脱落的固体颗粒在水汽中形成固液汽三相流冲蚀作用 ,使材料被除去 ,母体金属与介质直接接触 ,周而复始的连续作用使管壁减薄。通过论述 ,以期对炉管减薄有更清晰的认识 ,从而对蒸汽发生器的使用起到一定的指导作用
From the corrosion theory and influencing factors to explain the “steam generator tube failure analysis,” a paper reveals the phenomenon of steam generator tube thinning mainly due to internal surface corrosion, furnace tube radial cross-section of the cracks and secondary cracks Corrosion surface erosion and cavitation marks. The mechanism of wall thinning in steam generator is introduced. Under the condition of high temperature and high pressure, metal and water vapor come into contact with water to cause the corrosion of soda and water, forming the corrosion products mainly composed of iron oxide. The liquid in the furnace tube is heated in the flowing process, resulting in a large number of steam bubbles, resulting in destruction of the oxide film or even the parent metal during the collapse of the steam bubble. At the same time, stress and reactive anions damage the oxide film causing pitting; the presence of oxygen aggravates the corrosive effect. Cavitation can make the falling solid particles form solid-liquid vapor three-phase flow erosion in the water vapor so that the material is removed and the parent metal directly contacts with the medium. Through the discussion, with a view to reduce the thickness of the tube have a clearer understanding of the steam generator to play a guiding role