Case Study: Steering Column Components
Process: Conventional powder metallurgy
Secondary Processes: Heat treatment
Density: 6.95 g/cc³
- Tensile Strength: 1,030 MPa (150,000 psi)
- Compressive Yield: 1,450 MPA (175,000 psi)
- Apparent Hardness: 30 HRC minimum
End Use and Function
The steering column components—rake cam, left-hand inner cam, retainer guide, right-hand rake teeth energy-absorbing eccentric strap cam, column mounting insert teeth, and lefthand rake teeth—are all part of the steering column in the Chevrolet Colorado and GMC Canyon trucks. They’re key elements of the column’s tilt and telescope adjustment feature, serving a vital role in maintaining the column’s position during a crash event.
This component utilizes heat-treated diffusion alloyed steel. All the parts are fabricated to net shape; material selection emphasized strength and dimensional stability so there is no need for sizing prior to heat treatment. The rake cam has features that allow for a mechanical lock of the plastic lever, which is over-molded in an operation performed by Agapé Plastics, Inc. The design for the steering column tilt/telescope adjustment and lock— with a “pin pocket” that gives a positive detent feel—could only be achieved economically by PM.
- This design concept is now being incorporated into the design of new manual tilt/telescope steering columns.
- Without powder metallurgy, this design could not be feasibly produced.
- No machining operations