Compaction

Where it comes up

• Powdered metalNet-shape gears, bushings, and structural parts pressed from metal powder and sintered, with little or no machining.

Related terms

Green part

A green part is a powder metal part after compaction and before sintering. It holds its shape but has low strength, about like chalk, so it must be handled carefully. Green density, typically 6.4–7.2 g/cm³ for iron-based parts, sets final strength after sintering.

Sintering

Sintering is heating compacted metal powder below its melting point, typically around 2,050 °F (1,120 °C) for iron-based parts, in a controlled atmosphere so the particles bond metallurgically. It turns a fragile green part into a strong, finished component. Parts may then be sized, machined, or heat treated.

Tonnage

Tonnage is the force a press can apply, rated in tons, and the force a job requires. Stamping tonnage is estimated from cut length, material thickness, and shear strength. In molding and die casting, clamp tonnage must exceed cavity pressure times projected area to keep the tool closed.