Case Study: Brake Piston

Process: Conventional powder metallurgy
Hardness: 80 HRB
Tensile Strength: 565 MPa
Density: 6.9 g/cm
Yield Strength: 448 MPa

End Use and Function

This parking/emergency brake piston is for hydraulic transmissions used in zero-turn-radius lawn-maintenance equipment.

2014 Award of Distinction: Brake Piston
2014 Award of Distinction: Brake Piston

Fabrication

Made from FC-0208 iron-copper steel, the piston is compacted with three features on top and six on the bottom, using two upper and three lower punches plus a die shelf. The piston has a density of 6.9 g/cm³, a tensile strength of 565 MPa, a yield strength of 448 MPa, and a hardness of 80 HRB before steam oxide treatment. The part is an original design for PM, as its shape makes it impractical for traditional metal-cutting methods. It is pressed and sintered to net shape, requiring no secondary machining operations.

Results

The process for this part ensures 100% material utilization, eliminating waste at each step.