Conventional powder metallurgy (PM), also known as press-and-sinter, is a net-shape processing technology that yields components with little or no secondary machining operations. Utilizing this metal-forming technology was pivotal in reducing the cost of this component while enhancing the reliability and durability.

In the PM process, custom-blended metal powders are fed into a die, compacted into the desired shape, ejected from the die and then sintered (solid-state diffused) at a temperature below the melting point of the base material in a controlled atmosphere furnace.

The compaction step requires the part to be removable from the die in the vertical direction with no cross movements of the tool members. The sintering step creates metallurgical bonds between the powder particles, impacting the necessary mechanical and physical properties to the part.

Camshaft and water sprocket

This award-winning camshaft and water pump sprocket were developed for a three-wheeled, side-by-side moto roadster. These components are some of the most critical engine components on any vehicle. Tensile strength, hardness and impact toughness are critical and, for PM fabrication, had to meet or exceed requirements previously established with machined, wrought components during prototype development.

Fabrication

The water pump sprocket was especially challenging, as the customer desired a one-piece shaft/sprocket design. Compaction required a significant amount of powder transfer to the upper punch. The parts are made from a modified 4300 low-alloy steel powder that is warm-die compacted and high-temperature vacuum sintered to a typical density of 7.2 g/cm3, giving an ultimate tensile strength of 1,350 MPa (195,000 psi), 1.8% elongation and an apparent hardness of 45 HRC.

Results

The PM components represent a 40% cost savings compared with machining. The PM process offered a net-shape processing opportunity that saved an average of 30%–40% raw material usage versus machining.

Learn more about PM processes, explore case studies across market segments and find a PM fabricator all at PickPM.com.