Hot vs. Cold Extrusions
The metal extrusion process is a popular process in the metal fabrication world because it can produce long, strong pieces of metal formed from one solid piece of metal. In both hot and cold extrusion processes, a piece of metal is pressed through a die under enormous pressure. The pressure from the die shapes the metal into the desired finished shape. The pressure and lengthening of the metal gives the metal extrusions remarkable strength, even if they are thin and narrow pieces when the process is complete. The extrusion process is used to create a variety of shapes, including the t shape aluminum extrusion, c shaped extrusions, l extrusions, and h extrusions.
There are two main methods to create extrusions- hot extrusion and cold extrusion. Both methods of extrusion have their own benefits and drawbacks which make different extrusion manufacturers choose one or the other method. Some factories use both cold and hot extrusion to make pieces like t shape aluminum extrusion pieces or other popular extrusion shapes. Problems with this system is that the pieces require additional surface finishing and the cost of operating the machines is higher than cold extrusion machines.
Hot extrusion: Hot metal extrusion heats the metal to nearly 75 percent of the heat required to melt the metal. The hot extrusion process is beneficial because it takes less pressure to form the metal, and it takes less time than cold extrusion. Hot extrusion is also better for use with larger amounts of metal.
Cold extrusion: Most materials can be cold extruded. The metals that are most often used with cold extruding are lead, tin, aluminum, copper, titanium, and steel. Advantages to this system are that the metal will not oxidize, the finalized metal pieces have excellent mechanical properties, and the surface finish is better than with hot extrusion.