Textron Corporation

William J Chmura

Ronald S Slusarski

Charles B Burk

A method of thread rolling a cylindrical sintered P/M blank is provided comprising, forming a sintered cylindrical powder metal (P/M) blank of density ranging from about 75% to 92% of the actual density of said metal blank having a selected diameter larger than the final pitch diameter of a predetermined roll threaded product produced therefrom and not substantially exceeding the outside diameter of said predetermined roll threaded product. The P/M blank diameter selected is substantially inversely related to the density of the blank, the P/M diameter selected being correlated to produce a substantially full thread. The sintered P/M blank is then thread rolled using a threading die corresponding to the gage of the predetermined roll threaded product to be produced.

Thread forming of sintered porous metal shapes

Low-cost articles characterized by a surface of revolution, such as truncated spherical balls, e.g., plain spherical bearing balls, are provided made by the powder metal compaction and sintering of blanks followed, in the case of ball elements, by densification of the outer spherical surface by mechanical working, such as by roll-forming, the balls so produced being characterized by improved sphericity and dimensional tolerance and improved wear resistance combined with optimum resistance to corrosion. The spherical surface of the ball is substantially free of pores, has a work hardened structure and has a density at and adjacent the surface of at least about 95% of the theoretical density of the metal, the density substantially below the surface being less and ranging to as low as at least about 70% of theoretical density.

Powder metallurgy production of spherical articles, such as bearing

Sintered articles characterized by a surface of revolution, such as truncated spherical balls and spherical ball valves, e.g., plain spherical bearing balls, are provided made by the powder metal compaction and sintering of blanks followed, in the case of ball elements, by densification of the outer spherical surface by mechanical working, such as by roll-forming, the balls so produced being characterized by improved sphericity and dimensional tolerance and improved wear resistance combined with optimum resistance to corrosion. The spherical surface of the ball is substantially free of pores, has a work hardened structure and has a density at and adjacent the surface of at least about 95% of the theoretical density of the metal, the density substantially below the surface being less and ranging to as low as at least about 70% of theoretical density.

Sintered ball valve

A method is provided for partially densifying a selected surface portion of a sintered porous powder metal element while applying restraining pressure to other selected portions of said element in order to inhibit growth and cracking of said element during the partial cold deformation thereof. The method is particularly applicable to the production of annular bearing rings.

Method for the controlled mechanical working of sintered porous powder

Sintered articles characterized by a surface of revolution, such as truncated spherical balls, e.g., plain spherical bearing balls, are provided made by the powder metal compaction and sintering of blanks followed, in the case of ball elements, by densification of the outer spherical surface by mechanical working, such as by roll-forming, the balls so produced being characterized by improved sphericity and dimensional tolerance and improved wear resistance combined with optimum resistance to corrosion. The spherical surface of the ball is substantially free of pores, has a work hardened structure and has a density at and adjacent the surface of at least about 95% of the theoretical density of the metal, the density substantially below the surface being less and ranging to as low as at least about 70% of theoretical density.

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Southington, CT, United States of America

William J Chmura