Production and hot forming of components of spheroidal graphite iron with elevated mechanical characteristics with an essentially bainitic structure

摘要

Production and forming of components of spheroidal graphite iron with elevated mechanical characteristics consists of: preparation of a molten mixture of given composition; casting the molten mixture at 1350-1550 degrees C in a mould to obtain a draft component; extracting the draft component at a temperature (Ts) between the solidus and a temperature (AR3) representing the limit of the austenite domain; forming the draft component by hot plastic deformation to its final shape and dimensions at 1050 degrees C - Ar3 point; quenching the component to a temperature (Tb) within the bainite domain and maintaining it at this temperature for a given time (tb); and cooling the component to ambient temperature. The composition of the molten mixture (by wt %) is: (a) 3 - 4 C; (b) 1.7 - 3 Si; (c) 0.1 - 0.7 Mn; (d) 0 - 4 Ni; (e) 0 - 5 Cu; (f) 0 - 0.5 Mo; (g) a residual Mg adapted to the thickness of the components of between 0.025 and 0.80; and (h) the remainder being iron and production impurities, notably S at less than 0.015 and P at less than 0.10. An Independent claim is also included for such a spheroidal graphite iron with elevated mechanical characteristics with an essentially bainitic structure.