Sheet metal used for forming

Sheet metal is a flat metal product that can be supplied in sheet or coil form.

For the manufacture of mechanical parts, especially large ones, it is much more economical to shape sheet metal than to machine solid components by milling or other equivalent techniques. The result is a considerable saving in materials, as well as a reduction in mass that is often much sought-after (in transport, in particular).

This type of shaping is nevertheless limited by the technical possibilities of the processes used; for example, certain parts can be obtained by molding rather than by stamping sheet metal.

Nonetheless, sheet metal forming is used extensively in an infinite number of fields, including automotive bodywork, aviation, household appliances, metal furniture, kitchen equipment and more.

The metallic materials used in these sheets are reviewed.

The main standards will be cited, and an attempt will be made to define the forming field and give a few significant applications. The tables, which are highly simplified, are presented for information only, often for a narrow range of sheet thicknesses. Extracted from current standards, they have been reduced to the essentials and do not exempt you from consulting the original documents.

Note: since the last edition of this text, a number of EN standards have been published which have clarified the situation somewhat (see the article "Standard steel designations" [M 302] in the treatise Matériaux métalliques).

For carbon steels, due to the widespread use of surface coatings (electrolytic zinc coating, galvanizing, temperature-resistant coatings, etc.), European standardization policy has also changed:

• when the coating significantly modifies the formability of a steel (quenched or very hard coatings), specific standards indicate for each grade the new characteristics of plates obtained with this coating;

• when the coating has little influence on properties (cold-formed or not very hard, e.g. electrolytically deposited pure zinc), it now tends to group together in a single standard the specifications applicable to several grades of carbon steel (e.g. prEN 10346).

It's also worth noting that some draft standards, such as the EN 10346 standard we've just mentioned, are going through a difficult birth....