Why Powdered Metal?
Powder metallurgy is a recognized “green” technology and is sustainable due to:
- Raw powder sourced from other industries’ “waste”
- Net-shape capabilities
- Very high material-utilization factor
- Minimized energy inputs
The Powdered Metal Process:
- Provides good surface finishes
- Parts may be heat treated for increased strength or enhanced wear resistance
- Provides part-to-part reproducibility
- Suited to moderate-to-high volume part production
Advantage Sintered Metals
Advantages of Powdered Metal
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View Our Powdered Metal PartsContact UsPowder Metallurgy Process
There are two basic steps in the process:
- Compaction
- Sintering
- Compaction is the pressing or molding of the specific desired powder metal.
- This is the primary forming technique for creating the part.
- Fill and flow charterisitics of the powdered metal is developed and refined in this step to ensure proper metal fill and density after sintering.
Sintering involves heating the powdered metal compacts in vacuum or a reducing gaseous atmosphere to a temperature that is below the melting point of the primary constituent of the material. The metallic particles metallurgically bond and alloying takes place via diffusion processes.
Various Functions Of Sintering Furnace Atmospheres
- Delubrication
- Oxide reduction
- Sintering (diffusion processes)
- Carburization/decarburization
- Prevention of air ingress
De-Lubrication
In pre-heat zone:
- Lubricants melt, exude to surface of parts, or vaporize
- Oxidizing atmosphere needed to pyrolize lubricant decomposition products
- Gas flow adjusted to flush by-products of reaction towards charge end of furnace
- Inadequate de-lubrication leads to sooting and blistering of parts in hot zone of furnace
Hot Zone
- Low dew point
- Low oxygen content
- Admixed graphite fully in solution by time parts reach hot zone temperature
- Oxides are reduced
- Diffusion of alloy additions takes place
- Degree of alloying at end of hot zone determines microstructure after sintering
Cooling Zone
- Unheated region at end of hot zone
- Water jacketed cooling zone reduces part temperature prior to discharge
Atmosphere in cooling zone:
- Prevents ingress of air
- Prevents oxidation of parts
Sintering Atmospheres
- Nitrogen – Hydrogen
- Endothermic gas
- Dissociated ammonia
- Hydrogen
- Vacuum