The Powder Metallurgy Process
Powder metallurgy may be best described as the following process:
Metal powders are firstly consolidated into a shape under pressure. The resultant compact is then sintered at a temperature below the melting point of the major elements, so that bonds are formed between the particles, while retaining the shape of the compact.
The powder metallurgy process has three basic stages: mixing, pressing & sintering.
Mixing
Plain iron powder and a combination of other elements and additives are blended together into a fully homogeneous mixture. Each blend is tailored to meet the exact physical requirements of the finished component.
Mixing can be performed by the powder supplier or the P/M parts manufacturer.
Mixing Equipment Available:-
- 2 tonne conical blender for on-site mixing giving greatest consistency and flexibility.
- 300kg Blender
- 2x Laboratory blenders
Pressing
The blended powder is transferred to a bulk hopper and placed above the powder compacting process.
A controlled amount of powder is fed into a precision die and is compacted. Dimensions and density are closely controlled in this process. The compacted component is said to be in the "green" state.
Gt.B. has over 30 compaction presses ranging from 6 to 200 tonnes capacity. Warm compaction capability allowing increased density for improved physical properties.
Sintering
After pressing, the "green" parts are sintered by passing them through a furnace in which both temperature and atmosphere are strictly controlled. The part is heated to just below the melting point of the principal material so that the particles are fused, or sintered, together into a solid mass.
Gt.B. has a potential sintering capacity of over 5000 tonnes P.A. from 6 furnaces.
Recent acquisitions include high temperature furnace and vacuum furnace, allowing parts to be produced to near full density for increased physical properties.