Powder Metallurgy 101
Did you know?
Powder Metal technology utilizes upwards of 97% of input material and is classified as a green technology in metal manufacturing.
Powder Metallurgy (PM) is a continually and rapidly evolving technology embracing most metallic and alloy materials, and a wide variety of shapes. The PM process involves the pressing of metal powders into components through compaction and sintering.
Advantages of Powder Metal
PM is a versatile and efficient alternative to machining or casting. Its high predictability allows for the creation of parts that would be difficult or costly to achieve with competing manufacturing methods.
- Complex shapes and geometries
- Net shape manufacturing
- Material Savings, minimal machining and scrap loss
- Good surface finishes
- Cost-effective
- High-volume manufacturing
- Part-to-part consistency at exacting tolerances
- Versatility – a wide variety of composites, alloys, and other materials
- Long-term performance reliability in critical applications
- Sustainable manufacturing
- Reduction of secondary operations
Powder Metallurgy Process
The PM process involves three steps: powder production, compacting, and sintering. Secondary operations are available, but not necessary for most parts. You can choose from a variety of finishing operations to customize the properties of your part. These steps enhance your part’s performance.
Powder Production Process
Metal powders used in PM can come from a range of sources including ore mining, recycling of scrap or waste materials, and specialized powder manufacturing processes such as atomization, mechanical alloying, or chemical reduction. The choice of metal powder depends on factors such as desired properties, cost, availability, and environmental considerations.
Atomization – Molten metal is separated into small droplets and frozen rapidly before the drops come into contact with each other or with a solid surface. Typically, a thin stream of molten metal is disintegrated by subjecting it to the impact of high-energy jets of gas or liquid
Material Selection
The first step in the PM process includes selecting and blending the right materials to achieve specific material properties or improve performance. Materials such as iron, steel, aluminum, bronze, copper, or soft magnetic materials are mixed with lubricants to create the desired combination for your application’s needs.
Compaction
In the compaction process, your formulated mix of powder is fed into a precision die cavity and compacted under high pressure. Compacting produces a “green” part which has the size and shape of the finished product when ejected from the die. Although the part has the size and shape of the finished product, the strength comes from the metallurgical bonds formed in sintering. Once removed, the piece has sufficient strength to be transported to the sintering furnace.
Did you know?
Our capabilities span an incredible range. We can press parts as small as less than a centimeter in diameter, like precision bearings, up to massive transmission hubs for heavy construction equipment.
Press Tonnage Range
Sintering
During sintering, the green parts move into a furnace (capable of reaching up to 2,600° F), where they are heated and held at the sintering temperature just before the melting point, causing the particles to bond together. In this thermal process factors such as strength and performance are achieved. The atmosphere in sintering is controlled to enable oxide reduction and prevent decarburization, typically this is a combination of hydrogen and nitrogen.
Secondary Operations
Most parts are formed to net shape, but a variety of optional finishing operations can be performed. These secondary operations can enhance the tolerances, density, strength, shape, corrosion resistance or performance properties of any part.
- Heat Treatment (all types)
- Plating or Coatings
- Oil – Resin Impregnation
- Steam Treatment
- CNC Machining
- Fine Grinding
- Shot Peening
- Sizing
Powder Metal Components
PM has the capability to produce high-performance parts with complex geometries, tailored material properties, and cost-effective manufacturing solutions across various industries.
