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.