PM parts are used in a variety of end products such as lock hardware, garden tractors, snowmobiles, automobile engines and transmissions, auto brake and steering systems, washing machines, power tools and hardware, sporting arms, copiers and postage meters, off-road equipment, hunting knives, hydraulic assemblies, x-ray shielding, oil and gas drilling wellhead components, fishing rods and wrist watches. Canadian nickels are made from strip rolled from pure nickel powder.
The typical U.S. light duty vehicle contains about 35 pounds of PM parts. Pickup trucks average about 55 pounds of PM parts, and range from 40 pounds to 95 pounds depending on the number of cylinders and whether it is 2WD, 4WD, or AWD. The typical mid-size SUV/CUV averages 30 pounds of PM parts. And, the typical U.S. passenger car averages 15 pounds of PM parts. More than an estimated 1.5 billion PM hot forged connecting rods have been made for light duty vehicles produced in the U.S., Europe and Japan.
Commercial aircraft engines contain 1,500-4,400 pounds of PM superalloy extruded forgings per engine.
Iron powder is used as a carrier for toner in electrostatic copying machines. Americans consume more than two million pounds of iron powder annually in iron enriched cereals and bread. Iron powder is also used in hand warmers and waterproof cements.
Copper powder is used in anti-fouling paints for boat hulls and in metallic pigmented inks for packaging and printing.
Aluminum powder is used in solid fuels for rockets such as the booster rockets for the space shuttle program.
The basic conventional PM process uses pressure and heat to form precision metal parts and shapes. Powder is compacted (at room temperature) in a rigid precision die at up to 50 tons per square inch into an engineered shape like a gear. Think of 50 compact cars stacked vertically and you have the pressure it takes to press the powder. After part compaction and ejection from the die, the part is fed slowly through a special controlled atmosphere furnace to bond the particles together. They are metallurgically fused without melting, a phenomenon called “sintering”.
Other processes are also used to consolidate powders into finished shapes such as cold or hot isostatic pressing (CIP/HIP), powder forging (PF), metal injection molding (MIM), direct powder rolling, gravity sintering, and metal additive manufacturing (AM). One of these cutting-edge technologies, metal AM, builds parts layer-by-layer without the use of a mold or die, by sintering or welding each individual particle of powder.
In contrast to other metal forming techniques, PM parts are shaped directly from powders while castings are formed from metal that must be melted, and wrought parts are shaped by deformation of hot or cold metal, or by machining.