运行中渗碳的Incoloy 800H裂解管的研究

研究运行中渗碳的Ｉｎｃｏｌｏｙ ８００Ｈ裂解管的显微组织及合金元素的分布， 采用了电子探针定性定量分析微区成分。结果表明，裂解管渗碳后显微组织 发生显著变化，其内壁最高含碳量为３％，内壁基体最低含铬量为４％；渗碳 层厚度超过２ｍｍ，管内壁基体和碳化物中Ｆｅ，Ｃｒ，Ｎｉ含量不随渗碳层厚度 变化；基体Ｃｒ含量下降大于６％，合金由抗磁性的变为铁磁性的；Ｍ２３Ｃ６型碳 化物转变为Ｍ７Ｃ３型碳化物时的合金碳含量约为１．５％．

Study of Incoloy 800H cracking tube carburized during servicing

The microstructure and distribution of alloying elements of Incoloy 800H cracking tube carburized during servicing are studied. It is shown that the microstructure of cracking tube is changed remarkably after carburization. The highest carbon content of inner surface is 3%. The lowest Cr content in matrix of inner surface is 4%. Fe, Cr, Ni Content in matrix and carbide of inner surface are not changed with thickness of carburization layer when thickness of carburization layer is more than 2 mm. Alloy becomes ferromagnetic from diamagnetic when the loss of Cr content in matrix is more than 6%. The carbon content is about 1. 5% when M23C6 is transformed into M7C3.