Case Study: Crankshaft Sprocket
Process: Conventional Powder Metallurgy
Secondary Processes: Induction heat treatment and tempering of the teeth for durability
Materials: FC-0208 and FL-4405
End Use and Function
These three components, a rubberized crankshaft sprocket and two rubberized oil pump sprockets—a drive and a driven—go into a General Motors Generation II High-Feature V6 Engine, currently installed in the Cadillac CT6 and ATS, GMC Acadia, and Chevrolet Camaro.
Fabrication
The crankshaft and oil pump drive sprockets are made of FC-0208 (teeth are induction hardened and tempered) while the driven sprocket is warm-die compacted (teeth at 7.1 g/cm3) and made of FL-4405. The patented rubber design used on the crankshaft sprocket provides improved noise, vibration, and harshness (NVH) characteristics that exceed the engine manufacturer’s demands.
Results
- Fabrication via PM provides an estimated 30% savings over parts machined from steel bar or forgings.
- The annual production of 700,000 sprockets is projected to reach two million in 2018.
- While it would be possible to create these components using alternative processes of machining from wrought steel or steel forgings, powder metallurgy offers a solution at a lower price with better material utilization.