Corrosion behavior of inconel 625 alloy in the oxygen-rich and high-temperature slag

Abstract

Abstract: In order to solve the problem of low service life of spray gun for nickel top-blown smelting, Inconel 625 alloy was used as a substitute material, corrosion behavior and mechanism of Inconel 625 alloy were studied under actual working conditions: oxygen flow rate 15 000~42 000 Nm³/h and slag temperature 1 400 ℃.The microstructure, element distribution and hardness of the samples were analyzed by OM, SEM, EDS, EMPA and micro-hardness tester. The results showed that the formation of oxide film such as Cr₂O₃ oxide hindered the corrosion process during 15~20 h. The severe corrosion zone of the alloy occur in 0 μm to 250 μm on the surface, and the heat-affected zone is in 250~1 650 μm. Nb-rich and Cr-poor areas are corroded first. With the continuous formation and decomposition of the complex oxide film system composed of Cr₂O₃, Fe₂O₃, Cr₂S₃, Nb_0.1Ni_0.9, [Mg, Fe]₂SiO₄, the main elements in the alloy are corroded off, and Mg and S elements in the oxide film are derived from slag. The hardness of the corroded alloy surface decrease obviously.

Key words: Inconel 625 alloy, oxygen-enriched and high temperature, slag, corrosion behavior

CLC Number:

TG172.9

JIA Jin-feng, WANG Jiang, CHEN Da-lin, LIU Jun-zhao, WANG Zhen-ming. Corrosion behavior of inconel 625 alloy in the oxygen-rich and high-temperature slag[J]. Journal of Lanzhou University of Technology, 2023, 49(3): 9-14.

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