Powder metal, and powder metallurgy, have special materials and processes that make it stand apart from traditional and other machining processes. This truth applies to both possibilities and terminology.
To the auto design engineer or the electric hand tool parts purchaser, the intro to powder metallurgy can be rough. Using the glossary of metalworking terms below can help you speak the same language as your metal parts supplier.
Check it out below, and feel free to share it with your engineering or purchasing team!
Glossary of Metalworking Terms: Powder Metallurgy Edition
| 3D Printing | Die-less process that allows for unique shaping of plastic, metal, or other materials. 3D printing can be achieved in the industrial world using metal in powder form, somewhat similar to the process used by powder metallurgy companies. |
| Additive Manufacturing | Die-less process that uses powder to create a part in a way that resembles an inkjet printer. Also known as 3D printing. |
| Alloyed Powder | Metal powder consisting of two or more materials that are partially or completely alloyed with each other. |
| Atomized Powder | Powder produced by disintegration of molten metals or alloys into droplets, which solidify into individual particles. |
| B-H Curve | Shows the relationship between magnetic flux density (B) and magnetic field strength (H). |
| Compaction | Using high pressure to compact metal powder in a die. |
| Compressibility | Capacity of a powder to be compacted and densified under pressure. |
| Core Loss | Dissipation of energy in a magnetic core during its magnetization/demagnetization cycle. |
| Density | Mass per unit volume of a substance. Powder metallurgy is a great tool for producing high-density components. |
| Die | Metal block used in forming materials. Like molds, they’re generally customized to the component you’re building. |
| Ductility | Measurement of how much deformation a material can sustain before tensile fracturing occurs. |
| Eddy Loss | Eddy currents are loops of electrical current induced within conductors. Magnetic cores in alternating current (AC) devices cause energy losses, or core losses, due to eddy currents. |
| Electromagnetic | Anything that describes electric currents or fields and magnetic fields. Refers to a type of physical interaction between electrically charged particles. |
| Elongation | How much a workpiece stretches before it breaks (similar to a rubber band). PM is inferior to forged materials in this trait, but engineers often overspecify and use forging when elongation isn’t even necessary for their project. |
| Feedstock | Plasticized powder used as raw material in metal injection molding. |
| Ferromagnetic | When a component or material is iron-based and therefore has a high susceptibility to magnetization, which may persist after removal of the applied field. |
| Ferrous | A type of metal containing or consisting of iron. |
| Hard Magnets | Materials that retain their magnetism after being magnetized and are difficult to demagnetize. |
| Hardening | Process used to increase resistance to denting and improve the strength of a steel component. |
| Heat Treatment | Combination of heating and cooling operations to produce desired properties and microstructures. |
| High-Temperature Sintering | Generally used to process refractory metals due to their high melting temperatures. Benefits of high-temperature sintered parts include increased tensile strength, bending fatigue strength, and impact energy. |
| Hysteresis | Dependence of the state of a system on its history, particularly in relation to magnetism. A type of energy loss, similar to eddy loss. |
| Induction heat treatment | Process of heating a metal powder by electromagnetic induction, through heat generated in the object by eddy currents. The rapidly alternating magnetic field penetrates the workpiece, generating eddy currents inside the conductor. |
| Iron-Copper-Carbon | Premixes of iron-copper-carbon are used in well over 50% of all powder metallurgy applications. |
| ISO (International Standards Organization) | Aims to create standardization in manufacturing and other industries. Use of these standards helps companies make safe, reliable, and high-quality products. |
| Liquid-Gas Permeability | Amount of liquid or gas flowing through a porous object. Certain PM processes and materials can increase permeability. |
| Lubricant | Substance added to reduce friction between particles or between the compact and tooling surfaces. The lubricant is then removed during the sintering step. |
| Machining | Molding a piece of raw material into a desired final shape and size by a controlled material-removal process. In the hands of a highly skilled powder metallurgist, a component usually requires little secondary machining. |
| Mechanical Properties | Properties that reveal strength and elastic behavior. Many advanced powder metallurgy processes and materials offer little-known benefits to mechanical properties. |
| Magnetic Permeability | The relative ease with which a ferromagnetic material can support a magnetic field. |
| Metal Injection Molding (MIM) | Metalworking process in which finely powdered metal is mixed with binder material to create a "feedstock" that is then shaped and solidified. Like 3D printing, MIM offers superior shape-making capability but at an exorbitant cost. |
| Microstructure | The small-scale makeup of a material, as seen at 25× magnification on a microscope. |
| Milling | Removing metal from a larger piece. |
| Minimum Values | Represent a bottom floor of mechanical properties you can expect with MPIF’s Standard 35 materials. |
| MPIF (Metal Powder Industries Federation) | Develops standards for and promotes the metal powder industry. |
| Necking | Reduction in the cross-sectional area of the metal in an area typically measured during tensile testing. |
| Net Shape | Manufacturing a result identical to the final size and shape, so that minimal machining or other secondary processes are required. Very difficult to achieve without powder metallurgy. |
| Nonferrous | Metal in which the predominant element is not iron. |
| Porosity | Empty space in a material. Low porosity prevents corrosive substances from entering your components. Also, reduced levels of porosity are often related to improved mechanical and magnetic properties. |
| Powder Metal | Finely divided or powdered materials compacted into hardened shapes. |
| Powder Metallurgy | The manufacturing of components made from metal powders by forming and sintering. |
| Prealloying | Combining powders earlier in the melting process. You can use prealloyed powders to produce a wide variety of parts with high strength and hardness. |
| Refractory Metals | Metals that are extraordinarily resistant to heat and wear. |
| Resistivity | Resisting power of a material to the flow of an electric current. |
| Secondary Process | Application of finishing processes to the sintered part. |
| Shrinkage | When a component contracts in volume. Some metallurgy processes inevitably cause shrinkage -- sometimes up to 25%. |
| Sinter Bonding | Technique of joining two PM components that utilizes the differential sintering growth characteristics of the two materials. Increasing strength by the metallurgical bonding of particles through the thermal treatment of a powder or compact at a temperature below the melting point of the main constituent. |
| Sinter Brazing | Process that bonds two components with the help of a third, filler material. |
| Sintering | Heating powders so that adjacent particles fuse, resulting in a solid component with greater mechanical strength. |
| Soft Magnet | Material that is easily magnetized and demagnetized. |
| Soft Magnetic Composite (SMC) | Ferromagnetic powder particles ideally coated with a uniform layer of electrical insulating film. |
| Tensile Strength | Maximum stress a material will withstand before it cracks. |
| Tolerance | The amount of deviation in measurements that a design will allow. Usually stated in +/- form. Overly tight tolerances can result in production issues. |
| Tooling | The items that help you form powder metal into its final shape. Powder metallurgy tooling is less expensive than its reputation suggests. |
| Typical Values | The average value of mechanical properties you can expect with MPIF’s Standard 35 materials. It will depend also on how the fabricator sinters the material, along with other materials. |
| Ultra-High-Temperature Sintering | When unusually high temperatures are used for sintering ferrous materials. Only a few powder metallurgy companies in the world can handle this process, which grants even better properties than high-temperature sintering. |
| Yield Strength | How much a material can handle stress before it becomes deformed. |
What’s Missing?
Not seeing the information you need to start working more closely with powder metal? Chances are we’ve covered it elsewhere -- check out our blog.
Good luck on your journey!
