Metal cold working is the process in which it is formed into desired shapes at room temperature. The metal is subjected to high pressures or impacts which increase its hardness and tensile strengths. Cold working of metals can be done by various methods including cold rolling, pressing, drawing and deep drawing, etc.
The process produces potential dislocations within the metal structure. This makes the metal stiffer. It is less ductile and less malleable, and once cold working is done, the metal is difficult to change its shape. The metal is said to become work hardened after cold working. To make it malleable and ductile again, the metal can be subjected to the annealing process.
According to ASM Handbook of material selection and design thick plates, sheets and strips down to 1.6 mm (0.060 inch) can be prepared by hot rolling while cold rolling is capable of forming thinnest of all metal sheets steps from few micrometers to a fraction of the thousandth of an inch.
Sheet metal cold working can be used to produce controlled surface finish. The process consists of a set of two or more rollers spaced closed together, and the sheet or strip of metal is passed through them. The force exerted by rollers on the sheet reduces its thickness and increase the strength of the sheet.
During the cold rolling process, the rollers bow marginally which result in the sheets being a little thicker near the middle. The sheet metal tolerances are given in ASTM A568/A568M. For example for a 10 gauge sheet of steel, nominal diameter is 3.4163 mm (0.1345in), maximum diameter tolerance at the center is 3.568 mm (0.1405 in) and minimum at corners is 3.2639 mm (0.1285 in).
Sheet metal forming is typically done for carbon steel, alloy steel, stainless steel, copper, aluminum, and alloys of copper and aluminum.
通过金属冷加工制造金属板的另一种方法包括在模具和压制系统中进行的片材上的剪切和形成操作。压力机由50cm x 30cm的各种尺寸的床组成，到210cm x 140cm（20英寸x 12英寸x 55英寸）。
The pressing force ranges from 200 to 4500 kN (45-1000lbf). The speed of strokes varies from 100 strokes per minute to 15 strokes per minute for bigger sizes. The dies consist of four parts:
The die set is used to hold the punch, which shears the metal. The punch acts on the die plate, and stripper plate removes any scrap at the end of the cold working process. Other sheet metal cold working processes includes bending, curling, deep drawing, de-cambering, expanding, punching, rolling, spinning, stamping and wheeling, etc.
金属板有很多用途。Steel sheets are utilized in the manufacturing of automobiles, industrial equipment and for domestic purposes. Aluminum metal sheet is used in commercial aircraft manufacturing.
通过以下标准选择金属冷加工成形性：
For sheet metal working, the starting material is a flat rolled product such as hot/cold rolled sheet or a hot-rolled plate. Sheet metal is available normally in 15 standard gauges; the thickness ranges from 0.38 to 5.08mm.
There are several advantages of cold working apart from effect on ductility of metal such as:
有一些缺点，如：
Ductility of an object is defined as the ability to undergo sizeable plastic deformation without any fracture. According to ASTM A370, ductility is measured in percent permanent elongation after fracture in a 2in. Gauge length.
Conventionally this value is limited to 20-25% for cold rolling. During the cold working of metal, it is deformed plastically. The metal gets harder, the more it is deformed within its plastic region.
该方法也称为工作硬化或应变硬化。应变硬化是较强且刚性部件的制造过程的重要组成部分，以进行重载。应变硬化降低了金属的延展性和可成形性。
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