Composite insert for use in a piston

Abstract

An annular composite insert is cast which includes distinct particles such as cast iron dispersed throughout the base metallic alloy. The insert is then placed in a piston mold, and a piston cast such that the insert maintains a radially outer face generally flush with a radially outer surface of a piston head of the piston. The base metal of the poured piston is preferably the same as that of the insert so that the insert bonds to the piston head and shares the same thermal expansion characteristics. The insert is machined to form grooves adapted to receive a piston ring. The particles of the insert are exposed to provide superior wear resistance, support to the piston ring so that microwelding is reduced, and also to act as a dry lubricant in a preferred embodiment.

Dependencies are inferred from the claim text.