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Modelling and simulation of recrystallization, grain growth, and related phenomena are important tools for the fundamental understanding of microstructural evolution that takes place during the annealing and thermomechanical processing of steel. It is also important for the prediction of engineering properties. In this paper, the evolution of mean grain radius and the recrystallized volume fraction of steel was modelled using the statistical theory of grain growth originally developed by Lücke [1] and here integrated to take into consideration the effect of recrystallization. In particular, the effect of one free input parameter (initial distribution of grain radii) of the model is analysed without taking into account the textures effect.

Eurofer97 steel has been recognised in Europe as the reference steel for nuclear application under high radiation density. Following to this a detailed knowledge of microstructure evolution is required for such steel after thermo-mechanical processing. In this paper the effect of thermo-mechanical parameters on the mechanical behavior of Eurofer97 was investigated by hot rolling and heat treatment on pilot scale. Results show a strong effect was found of reheating temperature before rolling on the material hardness, due to an increase of hardenability following the austenite grain growth. A minor effect was found of the hot reduction and the tempering temperature in the total investigated deformation range. A loss of impact energy was found coupled with the hardness increase.

Super-ferritic stainless steels are characterized by structure and properties similar to those of more common ferritic alloys, with the advantage of higher chromium (Cr) and molybdenum (Mo) levels aimed to increase high temperature resistance and corrosion behavior in aggressive environments, such as seawater. This paper focuses on the corrosion behavior of recently developed super-ferritic stainless steels. Such steels are characterized by a Cr content ranging from 21% to 24% and very low carbon and nitrogen levels (C + N < 0.015%). Moreover, low nickel (Ni) and Mo contents are adopted in such steels, following to the high costs of such elements. [ABSTRACT FROM AUTHOR]

Many advanced steels are based on tempered martensitic microstructures. Their mechanical strength is characterized by fine sub-grain structures with a high density of free dislocations and metallic carbides and/or nitrides. However, the strength for practical use has been limited mostly to below 1400 MPa, owing to delayed fractures that are caused by hydrogen. A literature survey suggests that ε-carbide in the tempered martensite is effective for strengthening. A preliminary experimental survey of the hydrogen absorption and hydrogen embrittlement of a tempered martensitic steel with ε-carbide precipitates suggested that the proper use of carbides in steels can promote a high resistance to hydrogen embrittlement. Based on the surveys, martensitic steels that are highly resistant to hydrogen embrittlement and that have high strength and toughness are proposed. The heuristic design of the steels includes alloying elements necessary to stabilize the ε-carbide and procedures to introduce inoculants for the controlled nucleation of ε-carbide. [ABSTRACT FROM AUTHOR]