Many of the shapes you see made out of metal get that way through a process called metal extrusion. The first extrusion process for pipe making was patented by Joseph Bramah in 1797. He made pipe out of soft metals forced through a die with the use of a hand-driven plunger. Bramah also invented the hydraulic press, used by Thomas Burr in 1820 to make lead pipe. The process was furthered in 1894, when extrusion with copper and brass alloys were used.
Metal Extrusion Process
The extrusion process is used to make objects with a fixed cross-sectional profile. There are two extrusion processes, cold and hot. The particular metal to be extruded is in the shape of a cylinder called a billet. The billet can be up to 72 inches long. The billet is heated higher than the recrystallization temperature, but before the melting point. A copper billet is heated to 1100 to 1825 degrees F. The melting point for copper is 1984 degrees F. The die is loaded into the press and is preheated to keep the billet from sticking. When the hydraulic pressure is applied, the billet is forced through the die, squeezing out on the other side in the desired shape. The extruded metal is then air or water cooled, and finished to the required length. The hydraulic presses are very big, ranging from 230 to 11,000 metric tons. The pressures they can apply range from 4,400 to 101,500 psi.
Types of Metals Used for Extrusion
The types of metals used for extrusion are lead, tin, aluminum, copper, zirconium, titanium, molybdenum, beryllium, vanadium, niobium, and steel. They all have different melting point and extrusion temperatures. Some of the custom copper extrusions are angles, channels, component parts, connectors, and contact substrates. Metals and alloys can also be made into round or oval tube shapes, hollow square tube shapes, channel shapes, Z shapes, T shapes, H or I beam shapes, and L shapes.
Benefits of Metal Extrusion
Parts made by extrusion may not have the same dimensional accuracy or surface finish as machined parts, but machine processes produce scrap metal waste. Extrusion is more cost-effective, and there is no need to dispose of waste material. More extruded copper shapes are rods, bars, custom shapes, hex bars, half rounds, and coil stock. Contact a copper extrusion supplier for a virtually unlimited variety of shapes, sizes, lengths, and alloys.
Examples of electrical contacts are breakers, relays switches, and electrical discharge machining applications. You use electrical contacts every day without even thinking about it. When you flip a switch, a light goes on or off, almost like magic. You know that electricity is flowing when the light comes on or you hear the refrigerator, furnace, or air conditioner running. Electrical contacts are something we just take for granted. We don’t know or don’t want to know how they work until something goes haywire.
Electrical Contact Material
Since the discovery of copper about 9000 BC, civilization has been technologically advancing in leaps and bounds. Copper is used for a multitude of items and applications, from household uses to copper tubing, copper wire, and water pipes. A breaker in a fuse box, for instance, has a plastic housing with metal components inside. The metals used in electrical contacts can be palladium, palladium alloy, silver, silver alloy, silver graphite, silver tungsten, and base metal or plated base metal. Spring material can be copper, beryllium, copper alloy, nickel, stainless steel, and steel. These metals can be plated with gold, nickel, silver, tin, or other metal. The metal used will depend on where the electrical contact is used or how big of a load it must carry. Electrical contacts need to be oxidation resistant and have a high conductivity rating. High-power equipment brushes where abrasion will occur, so the metal surfaces need to be made of strong alloys. Some metals that augment the structural properties, such as strength, weldability, toughness, temperature strength, and corrosion resistance, are tungsten, nickel, graphite, and molybdenum.
Electrical Contact Assembly
Soldering metals together is a common method when heat strength and load are not a concern. However, brazed electrical contacts are stronger and can withstand higher temperatures and heavier electrical loads. Brazing can join almost all metals. Transit electrical contacts need the extra strength provided by brazing, with high density alloys using silver or copper blended with tungsten or molybdenum. Brazing is used for electrical components, pipe fittings, and metals with varied thicknesses.
In the automotive industry, there are electromechanical switches, sensor devices, and many more. A multitude of electrical contacts, switches, and relays are used in power transmission and distribution, low to medium voltage electric and diesel electric transportation, AC and DC motor controls household appliances material handling, and rail signaling, to name a few. A tungsten contact supplier can offer you the best electrical contacts that will provide you with years of reliable service.