Modelling carburisation in 9Cr-1Mo ferritic steel tube substrates in experimental CO2 atmospheres
journal contributionposted on 26.09.2019, 13:44 authored by M. S. A. Karunaratne, S. Yan, Rachel ThomsonRachel Thomson, Lawrence Coghlan, Rebecca HigginsonRebecca Higginson
By combining modelling and experimental work, new insights have been gained into the combined oxidation/carburisation of 9Cr-1Mo steels in CO2 rich environments. The breakaway-oxidation process is preceded by the rejection of carbon into the scale due to the poor solubility of carbon in the metal. Experimental TEM work reveals the formation of a carbide rich layer near the substrate surface which forms a further barrier against carbon ingress. The eventual oxidation of this layer could contribute to breakaway oxidation. A 2D finite-difference based diffusion model developed in combination with Thermo-Calc software underlines the role of specimen geometry on breakaway initiation.
- Aeronautical, Automotive, Chemical and Materials Engineering