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模拟不同的热处理使用条件,对耐热钢(Cr20-Ni25)辐射管试样进行了烧蚀试验,用金相法测定了腐蚀深度。初步确定,大气介质中含一定量H_2S气体,可加速腐蚀。但在试样表面渗碳,特别是渗碳后再覆盖一层固体渗碳剂,则腐蚀明显加剧,成为主要的促进腐蚀因素。对腐蚀产物的x射线衍射及电子探针分析表明,在含H_2S气的气氛中加热的试样,表面附着有很微量的FeS,而沿晶界只产生氧化物。因此,腐蚀的主要形式是晶间氧化。所得结论是,表面强烈增碳和氧化气氛是造成辐射管加速腐蚀的两个热处理因素。
Simulated different conditions of heat treatment, heat-resistant steel (Cr20-Ni25) radiant tube samples were ablated, and the corrosion depth was measured by metallography. It is initially determined that a certain amount of H 2 S gas in the atmosphere medium can accelerate the corrosion. But in the sample surface carburizing, in particular carburizing and then covered with a layer of solid carburizing agent, the corrosion increased significantly, becoming the main factor to promote corrosion. X-ray diffraction and electron probe analysis of the corrosion products showed that the sample heated in a H 2 S -containing atmosphere had a small amount of FeS attached to the surface and only oxides along the grain boundaries. Therefore, the main form of corrosion is intergranular oxidation. The conclusion is that the strong carbon and oxidizing atmosphere on the surface is the two heat treatment factors that cause accelerated corrosion of radiant tubes.