Powdered Metal Process
Quick High Temperature Powder Metal Links
- What is High Temperature Powder Metal
- Benefits of High Temperature Powder Metal
- High Temperature Powder Metal Process
What is High Temperature Powder Metal?
High Temperature PM or Powder Metal focuses on providing a cost-effective alternative to forging, stamping, casting, and machining processes. It combines the high volume process of powder metal compaction with superior physical properties achieved through high temperature, controlled atmosphere sintering.
High Temperature Powder Metal Benefits
The High Temperature Powder Metal (PM) process offers benefits that are not readily available with other metal-working processes. Consequently, PM components are rapidly becoming an effective alternative to castings, forgings, and machined parts.
Design Benefits of High Temperature Powder Metals:
- Material Efficiency One of the cost advantages of the PM process is that the finished product uses virtually 100% of the metal powder consumed. This eliminates the waste found in the stamping, fineblanking, or machining processes when producing components with holes or varying thickness.
- Intricate Shapes With essentially no cost added, PM is easily able to provide internal or external splines, gears, knurls, or knobs. Features can be off-center or partially through, such as eccentric holes or hidden pockets.
- Close Tolerances High precision dies, punches, and core rods produce net shape components with closer tolerances than castings, forgings, and stampings. Components may be coined or machined if additional dimensional precision is required.
- Unique Material Properties Powder Metal offers a variety of standard alloys to suit a majority of requirements; however, custom blends of any size can easily be manufactured to meet specific material requirements.
- Labor Efficiency Automatic, rapid cycle presses produce PM components consistently. While intricate tooling set-ups may be somewhat lengthy, longer press runs and continuous sintering efficiently amortize this portion of the cost.
- Reduced Assemblies In many cases, functions that would require intricate multiple parts and assembly steps are consolidated into a single PM component that minimizes manufacturing steps and reduces cost.
High Temperature Powder Metal Process
Powder metal is a mature process, beginning with decorative applications as early as 3000 BC and evolving to high volume, industrial production just over 100 years ago. Advances in equipment and materials over the past 50 years have led to significant improvements in the process.
High Temperature Powder Metal components use those advances to achieve better properties than conventional Powder Metal while continuing to provide cost benefits when compared to other metal forming processes.
While conventional Powder Metal processing sinters parts to 82-88% of the theoretical density, High Temperature materials are carefully processed to achieve densities ranging from 88% - 94% of theoretical density. Since material properties such as elongation, yield strength, corrosion resistance, and magnetic properties are directly related to density, High Temperature materials significantly outperform their conventional counterparts.
High purity metal powders and additives are selected to provide unique physical properties tailored to the customer's requirements. The powders are blended with lubricants which aid powder flow, green density, and green strength. Mixing metal powders in the solid state provides opportunities to engineer a wide variety of material properties unique to Powder Metal.
Powder metal flows from the feedshoe into the die cavity where multiple punches compress it to half its original volume. Intense compacting forces first realign, then deform the metal particles, creating localized mechanical bonds, forming a 'green' part. Green parts are ejected and conveyed mechanically to minimize handling damage. With presses from 4 to 550 tons capable of multiple motions, we are able to produce even the most complicated parts.
Our high-temperature (above 2300F) sintering capabilities yield many benefits, such as: improved metallurical bonding, densification, ductility, and impact energy. The initial sintering stage removes binders and lubricants and cleans the surface of the metal particles, ensuring excellent mechanical properties in the finished component. Time at temperature provides the energy that transforms the mechanical bonds into metallurgical bonds. Sintering below the melting point creates components with 88% to 94% of the alloy's theoretical density.
The strength of Powder Metal is the net shape capability — often providing a finished component after the sintering operation. Sizing or coining operations are used for more demanding dimensional requirements. Additional feature complexity can be gained using a variety of machining applications, including grinding, turning, milling, tapping, etc. Oil impregnation utilizes Powder Metal's porous pathways as a built in lubrication reservoir. Other surface treatments are also available to achieve specific requirements.