As you know, black sheet is produced by hot rolling and oil sheet is produced by cold rolling. When buying black sheet and oil sheet, you should have enough information about both types of sheet.
Usually, sheets that are produced by hot rolling method have lower quality than cold sheets. When hot sheets are on the production line, they are initially formed into the same final shape. So it does not need to be reheated. As a result, after producing the black sheet, the amount of shape and size change in the black sheet is less than the oil sheet.
What is the oil sheet?
Sheets that are produced by cold rolling are known as oil sheets in common language. The oiled sheet has a polished, smooth and uniform surface. The oiled sheet has a high thickness before cold rolling, and the thickness of the sheet decreases with cold rolling. Because of the beautiful appearance of the oiled sheet, it is used in places where the appearance of the product is important.
What is the black sheet?
One of the products of hot rolled sheets is black sheet, which is produced at a temperature higher than 930 degrees Celsius. Black sheets have an uneven and cloudy surface, that's why they are called black sheets.
In order to smooth the surfaces of the sheets and remove the dullness and opacity, the surface of the sheets can be cleaned to a large extent by operations such as acid washing. straightened.
What is the difference between black and oily sheets?
Difference in size: The final sheet produced by hot rolling has a rough surface and the dimensional tolerance of the sheet is not accurate. The thickness of the black sheet in hot rolling is reduced from 25 to 6 mm. If the thickness of the sheet is small, it can be wrapped around an axis.
Coils produced with a small thickness, the raw material of the sheet is oiled in the cold rolling process. In cold rolling, sheets with low thickness, high surface finish and low tolerance are produced.
Quality difference: Machines that are used to produce sheets by hot rolling method. They are very advanced and expensive. These products are of high quality and have a lower price than the oiled sheet. Hot sheet is used for large size products and has a distinctive shape compared to other products.
The surface of cold rolled products is smooth and uniform with a high quality coating. Rebars produced by cold rolling have higher strength and hardness than rebars produced by hot rolling. This process is the opposite in the production of steel sheets, and the amount of carbon used in the sheets produced by hot rolling is higher. Therefore, the black sheet has more strength than the oil sheet.
The amount of carbon used in the black sheet is more than the oil sheet, for this reason, the oil sheet has higher flexibility than the black sheet.
Price difference: The price of oiled paper is almost twice the price of black paper. The reason for the higher price of cold sheet is the more complicated process of cold sheet production.