Spheroidal cast iron particularly for piston rings and method for obtaining a spheroidal cast iron
AssigneeERRE-VIS S.p.A.
InventorsAlberto Molinari, Dimitri Anguillesi
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Abstract
A spheroidal cast iron, particularly for piston rings for pistons of engines, with a particular alloyed chemical composition and subjected to a heat treatment known as austempering, which comprises an austenitization treatment followed by an isothermal hardening treatment, has mechanical characteristics that are comparable with those of the steel currently used to produce piston rings, while maintening the best tribological and self-lubrification characteristics of spheroidal cast irons, and a process suitable to obtain said spheroidal cast iron.
Claims10
Spheroidal cast iron comprising the following elements:
- Fe, C, Si, Mo and characterized in that it furthermore comprises Ni, RE, and at least one element among Ti, V, Nb.
A process suitable to obtain a spheroidal cast iron comprising the steps that consist in:
- providing a conventional basic cast iron
- melting the base cast iron
- checking the molten metal during the preparation and completion of the melting of the basic cast iron by taking samples, which undergo chemical analyses in order to check their composition
- adding chemical elements chosen from the class that comprises C, Si, P, S, Mn, Cu, Mo, Cr, Ni, Ti, V, Nb
- inoculating spheroidizing agents in the molten mass, said agents being constituted by a silicon base which comprises RE with the addition of at least one of the elements chosen from the class that comprises Mg, Ca, Ce, Ta, Sr, Al, RE.
Dependencies are inferred from the claim text.