Effect of Cold Deformation upon Ageing of Superaustenitic Stainless Steels
Cold rolling followed by ageing in two grades of superaustenitic stainless steel was performed in order to assess the effect of cold deformation on the precipitation characteristics of these steels. Samples were cold rolled from 20% to 60% reduction in thickness and aged within the temperature range of 650οC to 950οC for times up to 120h. Following ageing precipitation of secondary phases took place, with sigma (σ) phase formation being the predominant precipitate species forming. Secondary phases have been reported to form following isothermal exposure to high temperatures, yet the precipitation behaviour of cold deformed samples has received less attention. When compared to the ageing characteristics of undeformed samples, cold deformation was found to accelerate precipitation during ageing. This study helped clarify a time-temperature-transformation regime relating isothermal ageing of cold deformation that could be applied to these steels in order to avoid occurrence of undesirable microstructural constituents with the associated reduction of mechanical and corrosion properties.
T. Chandra, N. Wanderka, W. Reimers , M. Ionescu
T. Koutsoukis et al., "Effect of Cold Deformation upon Ageing of Superaustenitic Stainless Steels", Advanced Materials Research, Vols. 89-91, pp. 301-306, 2010