As of lately, cold-rolled steel has been in increasing demand on the metal-roll market, and this has its own reasons. The cost of production is relatively not high. But this is not the most important thing. As practice has shown, sheets made by cold rolling have a longer service life compared to the hot-rolled method. Cold rolled is stronger and more profitable in terms of transportation.
There are two main types of pressure treatment, hot and cold rolling. The difference between them is the temperature at which these processes are carried out. As the name implies, during hot rolling, the intermediate product is preheated. The heating temperature depends on the thickness of the sheet. The thicker it is, the higher the temperature must be. Cold-rolled coils are made without pre-heating, which presupposes some features. But before we start discussing them, let’s first clarify the production technology.
Cold-rolled steel coils
Cold-rolled steel is one of the most sought-after types of modern rolled metal. In the total amount of steel produced, the volume of sheet metal is continuously increasing. It is made by the method of cold rolling. Ductile metal is treated with a special method by pressure without pre-heating. It is available in two forms – in a cold-rolled sheet and in rolls. Finished products can have different lengths and sizes, with a cut edge, with compression etc.
The growing demand for cold-rolled steel is due to higher quality characteristics than hot-rolled products. In addition, the production of sheet metal with a thickness of 1 mm and less is economically feasible only in a cold way. Conventional carbon, high-quality carbon, alloyed and high-alloy steels, corrosion-resistant, heat-resistant alloys are subjected to cold rolling. The chemical composition of the processed steel determines the properties of the resulting metal-roll and, to a certain extent, the area of its application.
Hot-rolled steel coils
Hot rolled metal is easier to process. For products manufactured by the method of hot rolling, low-grade, lower cost steel is more commonly used. Finished products are often scaled and require additional processing. Since it is impossible to calculate the limits of metal deformation during cooling, the geometry of hot-rolled metal does not differ in severity (uneven thickness, irregularities at the edges and corners). The blank is a flexible hot-rolled sheet that passes through the rolls under pressure. Before this operation, the surface of the work piece is etched in order to achieve a higher quality product. After rolling we can receive a sheet with a thickness from 0.35 mm to 5.00 mm.
For the production of steel used high grades. Such strong heating of the metal leads to the formation of oxide scales. If you do not remove them completely, it will lead to hidden or obvious defects in hardware. Warming up is uneven over the entire area of the sheet, because of this there is a difference in such parameters as sheet thickness, width and shape.
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