Abstract: A sintered powder metal part is prepared for machining by injecting grease into the surface of the part to be machined to a depth at least equal to the depth of machining. The grease is injected under very high pressure using repressing tooling by applying a certain volume of grease between the surface to be machined and the mating tool surface and applying pressure sufficient to uniformly inject the grease into the surface. A rim may be formed in the part adjacent to the surface which acts as a seal during grease injection and is compressed into the part.

Abstract: A method for high density long fill compaction of metallic powders uses a precisely temperature controlled mold and a dry sprayed lubricant which has the characteristic of softening on contact with the mold and smearing on the mold wall during compaction, yet on ejection not causing powder adherence.

Abstract: A unitary powder metal gear or sprocket (10) has a teeth region (16) which extends 2-5 mm below the tooth root diameter and a body region (14) radially inside of the teeth region (16). The teeth region (16) is pressed to a higher density than the body region (14) in a two chamber compaction die. The teeth region (16) is made of a sinter or induction hardening material, and the body region (14) is made of a liquid phase sintered material. Materials for the teeth (16) and body (14) regions are selected for compatibility by compacting them into a bimetallic strip (20, 22) with the teeth material (18) on one side and the body material (19) on the other side, sintering the strip (20,22) and observing the amount it bends.

Abstract: In a bearing cap of the type which is bolted to a bearing support structure so as to define a bearing bore between the cap and the structure and in which bolt holes for securing the cap to the structure extend through feet of the cap and into the structure, the cap having at least two of the feet, one foot on each side of the bore with at least one bolt hole extending through each foot, the improvement wherein:the cap is sintered powder metal and has an integral boss protruding from the foot around the bolt hole.

Abstract: A sintered powder metal part is surface densified by surface heating followed by repressing. Surface heating is preferably done to a temperature which is just below the critical temperature where the steel alloy material of the part transforms from a ferritic to an austenitic microstructure. Repressing is in a die set which is smaller than the part by 10% of the surface heated depth. The hot skin is compressed and densified between the die and the cooler, and therefore less malleable core of the part Following surface densification, the part may be resintered and/or heat treated.

Abstract: Inner or outer cylindrical worked surfaces of powder metal components are bearingized by orbiting tapered rollers against them using a tapered mandrel having points for impacting the rollers against the worked surface.

Abstract: A bearing insert for being cast into an aluminum alloy engine block is made by a ferrous powder metal sintering process to make a skeleton structure which is permeable to the molten aluminum alloy in the block casting process. The insert is made of a material having a similar composition as the bearing cap so as to equalize machining and thermal expansion properties of the cap and block so as to provide improved roundness of the bearing in the machining operations for forming the bearing support and in operation of the engine.