Abstract: A method of carburizing a powder metal part involving more than one carburizing step. In a pre-forging carburizing step, a powder metal part that is less than fully dense is carburized to establish a pre-forging carburization profile. After the pre-forging carburizing step, the powder metal part is forged so that the powder metal part is increased in density and the pre-forging carburization profile is transformed into an as-forged carburization profile. In a post-forging carburizing step following the forging step, the powder metal part is again carburized, thereby resulting in both further diffusion of carbon from the as-forged carburization profile into the powder metal part and further introduction of carbon into the powder metal part at a surface of the powder metal part.

Abstract: A method of forming a powder metal forging, which includes the steps of providing a preform including a sintered powder metal composition; inserting the preform in at least one part of a die set having a top die and a bottom die, at least one of the top die and the bottom die defining a helical forge form therewithin; closing the die set wherein the top die is contacting the bottom die; and compressing the preform in the forge form using an upper punch including a core rod and a lower punch, the compressing step occurring after the closing step, the compressing step resulting in a formed part having a helical outer surface. The method and apparatus of the present invention is particularly advantageous when forming a powder metal forging helical outer surface and an inner contour such as a cylindrical inside diameter.

Abstract: A method and apparatus for forming a powder metal forging (B) includes a die set (A1D) for forming the powder metal forging (B) having a first die (A) complementary with a second die (D) in a longitudinal direction (ZC). The die set (A,D) has at least two features (10) of dimensions with a longitudinal component (10) and a lateral component (18), and at least the lateral component (18) varies along the longitudinal direction (ZC), at least one such feature (10) in each die (A,D). Each of the first die (A) and the second die (D) includes a castellated parting interface (12,13) dissecting the laterally varying internal longitudinal feature (10, 18) in the first die from the laterally varying feature (10, 18) in the second die (D). The castellation (12,13) in the dies (A,D) provides forged powder metal parts (B) with features of opposite drafts without trapping the part (B) in the dies (A,D).

Abstract: A differential assembly, bevel gears for the assembly, and a method of making the bevel gears are disclosed. The bevel gears have a form which provides for high power density transfer.

Abstract: A method of forming a powder metal forging, including the steps of: forming a preform including a sintered powder metal composition; inserting the preform in a die set having a bottom die and a top die, the die set defining a forge form therewithin, the die set being in a closed position wherein the top die is contacting the bottom die; and compressing the preform in the forge form using an upper punch and a lower punch, the compressing step resulting in a formed part. The closed die set minimizes or eliminates flash in the formed part, particularly in the contoured surfaces, which allows the forging to be through hardened by direct quenching after the forging operation, without the need to remove hardened flash from these surfaces.

Abstract: A differential assembly, bevel gears for the assembly, and a method of making the bevel gears are disclosed. The bevel gears have a form which provides for high power density transfer.

Abstract: A method and apparatus for forming a powder metal forging (B) includes a die set (A1D) for forming the powder metal forging (B) having a first die (A) complementary with a second die (D) in a longitudinal direction (ZC). The die set (A,D) has at least two features (10) of dimensions with a longitudinal component (10) and a lateral component (18), and at least the lateral component (18) varies along the longitudinal direction (ZC), at least one such feature (10) in each die (A,D). Each of the first die (A) and the second die (D) includes a castellated parting interface (12,13) dissecting the laterally varying internal longitudinal feature (10, 18) in the first die from the laterally varying feature (10, 18) in the second die (D). The castellation (12,13) in the dies (A,D) provides forged powder metal parts (B) with features of opposite drafts without trapping the part (B) in the dies (A,D).

Abstract: A method of forming a powder metal forging, which includes the steps of providing a preform including a sintered powder metal composition; inserting the preform in at least one part of a die set having a top die and a bottom die, at least one of the top die and the bottom die defining a helical forge form therewithin; closing the die set wherein the top die is contacting the bottom die; and compressing the preform in the forge form using an upper punch including a core rod and a lower punch, the compressing step occurring after the closing step, the compressing step resulting in a formed part having a helical outer surface. The method and apparatus of the present invention is particularly advantageous when forming a powder metal forging helical outer surface and an inner contour such as a cylindrical inside diameter.

Abstract: A method of forming a powder metal forging, including the steps of: forming a preform including a sintered powder metal composition; inserting the preform in a die set having a bottom die and a top die, the die set defining a forge form therewithin, the die set being in a closed position wherein the top die is contacting the bottom die; and compressing the preform in the forge form using an upper punch and a lower punch, the compressing step resulting in a formed part. The closed die set minimizes or eliminates flash in the formed part, particularly in the contoured surfaces, which allows the forging to be through hardened by direct quenching after the forging operation, without the need to remove hardened flash from these surfaces.