Sintered sprocket and manufacturing method

Abstract

In a sintered sprocket at least the tooth surface layer contains carbon in the range from 0.6 to 1.2 mass % and nitrogen in the range from 0.05 to 0.5 mass %. The structure of the tooth surface layer comprises a tempered martensite structure and a residual austenitic structure, the residual austenitic structure being 10 to 50 volume % of the tooth surface layer. The density of the tooth surface layer is at least 7.4 g/cm3. Metallic elements contained in a base material comprise at least one metal selected from Ni, Cu and Mo in an amount in the range from 0.5 to 5 mass % the balance being Fe and inevitable impurities. The sintered sprocket exhibits high strength and wear resistance and can be manufactured at low cost.

Dependencies are inferred from the claim text.