Powder metallurgy production of spherical articles, such as bearing elements

A method for producing a powder metallurgy article of manufacture characterized by a convex surface of revolution which comprises,

• forming a sintered porous powder metal blank having said surface of revolution formed about a fixed axis passing through said blank having an average density ranging from about 70% to 90% of the theoretical density of the metal, and then mechanically working by roll forming substantially said entire convex surface of revolution of said article sufficient to produce a highly dense mechanically worked zone at and adjacent said convex surface of average density of at least about 95% of theoretical density of the metal with the pores at the surface thereof substantially closed,
• while maintaining the remaining portion of the sintered metal inwardly of the dense zone and extending towards said axis substantially porous and having an average density ranging from about 70% to less than 95% of the theoretical density of the metal.