Sheet Metal Work
Sheet metal work include the various processes involved in heating and shaping metal sheets. In general, sheet metal is created by compressing the metal materials between rollers. Once compressed, the sheet can be bent, drawn, cut, punched, or stretched. These processes are responsible for giving sheet metal a different shape, surface, or size. Most metal working processes require heating the metal.
Heating processes are used to harden or soften sheet metal by heating or cooling it until it reaches the desired level of hardness, Several important techniques may be used in the heat treating process, including annealing, quenching, and tempering. Annealing is a process by which a metal is heated and then cooled very slowly, leaving the metal soft and ductile. Quenching, on the other hand, refers to the rapid cooling of metal that can increase the metal's strength. In tempering, the metal is heated to extreme heat, between 400 and 600 degrees Celsius, and maintained at this temperature until the carbon diffuses to produce bainite or pearlite. Tempering also strengthens the metal.
After the metal is heated, it can be stretched into various forms. During stretching, sheet metal is clamped around the edges and stretched to make various products, including car doors. Sheet metal can also be simply bent or curved. Bending involves straining sheet metal by moving it about a linear axis on a neutral plane.
Other than bending and stretching, several other techniques may be used to shape sheet metal. Drawing and deep drawing, for instance, are stamping processes that make flat sheet metal into various three dimensional forms. Cutting changes the size of the sheet and can also be used to cut the metal into shapes. Comparatively, punches perforate the sheet and cut specific shapes out of the metal.