On sheets – materials, standard sizes and shaping processes
- 20. February 2022.
- Posted by: kasteel_admin
- Categories: Procurement of metals, Sheet metal
Sheets are the basis of engineering today. We can find it where ever we look – from automobiles and machines to building facades and furniture.
In order to fully utilize the potential of sheets, it is necessary to know and recognize their key characteristics. This includes materials, the differences in manufacturing processes and possible shaping methods.
What is a metal sheet?
A metal sheet is one of the options and shapes for the sale and purchase of metal on the marketplace. A sheet is every metal of thickness between 0.5 to 6 mm. However, there are other units used to categorize metal according to thickness.
First we have the metal foil. A metal foil is often found in combination with aluminum, usually called aluminum foil. The thickness of the foil is usually up to 0.2 mm. Then we have the metal sheet. The thickness of metal sheets ranges from 0.5 mm to 6 mm. All above that is a metal plate.
A thin sheet is easily shaped, while still retaining great strength. Thanks to its relatively low price, it fits well into most engineering projects and is therefore widely present.
Most common materials
Almost all most commonly used engineering metals are also used in the form of sheets. Some of them are carbon steel, stainless steel, copper and aluminum.
Metal sheets have the same mechanical characteristics as their base metal. Therefore, steel sheets have the same pull strength and durability appropriate for the use in construction and machinery. Also, copper sheets are often used as a decorative layer on modern buildings.
Hot-pressed vs. cold-pressed sheets
There are two ways to produce sheets – hot pressing and cold pressing. With construction steel, cold-press is used only up to 3 mm of material thickness. At higher dimensions, sheets and plates are hot-pressed for reasons of profitability.
Even though the process of hot-pressing starts at 3 mm for stainless steels, cold-pressing covers all sheets, i.e., all thicknesses up to 6 mm.
With high-precision use, cold-pressed steel sheets are preferred, because a higher control over the dimensions of the final product can be exercised. This is because, with hot-pressed steel, the steel slightly contracts after cooling down, which can lead to slight deformities in the shape.
Some processes for shaping sheets
Among the host of possibilities of shaping sheets, the choice of the appropriate method mostly depends on the usage of the final product. One should keep in mind that most of these methods yield a seemingly similar or almost the same result. One should also consider the price (often dependent on the size of the series), availability and required precision.
Sheet bending
Bending is the process of shaping in which the sheet is bent into the required shape by applying strain force. The sheet is bent by achieving a plastic deformation. That disables the sheet to revert back to its previous shape.
Air-bending with a V-matrix
Parts such as flanges and creases are generated by bending. The most common form of bending is V-bending. U tom slučaju matrica u obliku slova V i bušilica zajedno vrše pritisak kako bi se dobio željeni oblik. Savijanje rubova još je jedna uobičajena metoda savijanja prirubnica pomoću matrice za brisanje i bušilice.
The production process of deep pulling
Deep pulling is the process of shaping sheets where the shape of the sheet is changed into the required shape in several phases by means of several molds. It is considered deep pulling only if the depth of the formed shape exceeds the original thickness of the sheet.
Blows and matrices are used to form changes in each phase of the process. In this process, the sheet is transformed into many different shapes, such as fuel tanks, sinks, and automobile parts. Deep pulling is usually used for production of large series.