Case Study: Gear-Race

Process: Conventional powder metallurgy
Tensile Strength: 60,000 psi
Density: 6.7 g/cm³,
Yield Strength: 50,000 psi

End Use and Function

The powder metallurgy (PM) steel gear-race is used in the OnTrac2 GPS-assisted steering system. The system positions agricultural planting and harvesting equipment to more accurately perform tillage, spraying, and spreading, as well as reducing skips and overlaps, thus reducing fuel consumption.

2012 Grand Prize: Gear-Race
2012 Grand Prize: Gear-Race

Fabrication

Molded to a density of 6.7 g/cm³, the part has an ultimate tensile strength of 60,000 psi, minimum yield strength of 50,000 psi, 125,000 psi transverse rupture strength, and 23,000 psi fatigue limit. The complex net-shape design features 112 gear teeth and 16 assembly holes.
The component is molded near-net shape, except for the tapping/threading of 14 assembly holes, turned relief under the gear teeth, and trimming of the ID and bevel.

Results

  • 60% cost savings over the previous machining method of making the part.
  • Designing with powder metallurgy reduced the assembly part count from 24 to 6 parts.
  • Selecting PM also cut lead times and allowed for easier assembly and disassembly in the field.