Author:
Zurek J.,Cosler H.,Quadakkers W. J.,Naumenko D.
Abstract
AbstractIn the present work, the high-temperature decarburization of the austenitic stainless steel S304HCu in Ar–4%H2–xH2O at temperatures between 1000 and 1150 °C was investigated. The focus was on determining parameters that influence the decarburization rate during heat treatment. Thermogravimetric experiments were performed with simultaneous measurements of CO release from the sample using a mass spectrometer. The variation of the experimental parameters included the composition of the atmosphere during pre-oxidation and decarburization, the temperature and the sample thickness. The results indicate that the loss of carbon from the specimen occurs faster through reaction of Cr2O3 with C from the steel compared to the reaction of C at the steel surface with H2O, provided that in the former case CO can easily evaporate. The overall decarburization process is governed by competing reactions; the destruction of chromium oxide by C and the formation of oxide scale by water vapour. The relative rates of these two reactions determines whether decarburization will occur or whether formation of a protective oxide stops the release of CO, the latter being promoted at lower temperatures and high water vapour contents. A dense, sufficiently thick chromia scale retards the onset of decarburization but does eventually not stop the carbon loss. Indications were found that the destruction of a pre-formed chromia scale by carbon involves a two-step process whereby presence of hydrogen is important.
Funder
Forschungszentrum Jülich GmbH
Publisher
Springer Science and Business Media LLC
Reference36 articles.
1. H.-J. Grabke, E. Marie Müller, and G. Konczos, Scripta Metallurgica 14, 159 (1980).
2. H. D. Alvarenga, T. V. De Putte, N. Van Steenberge, J. Sietsma, and H. Terryn, Metallurgical and Materials Transactions A 46, 123 (2015).
3. E.J. Hilinski and G.H. Johnston, in 2014 4th International Electric Drives Production Conference (EDPC), (2014), p. 1.
4. W. Zeng, Y. Guo, F. Dai, L. Pan, Y. Lei, and T. Liu, Corrosion Science 221, 111251 (2023).
5. S. Choi and S. V. D. Zwaag, ISIJ International 52, 549 (2012).