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Carbon steel sheets have become the best material for a diverse range of products. They are used to varying degrees on boats, buildings, bridges, storage tanks and pressure vessels. As carbon steel sheets can be manufactured to many chemical and physical requirements, they meet the needs of many types of applications.


Steel is considered carbon steel when no minimum grade is specified for aluminum, chromium, cobalt, columbium, nickel, titanium, molybdenum, tungsten, vanadium. , zirconium or any other element added to achieve the desired alloying effect, where the prescribed minimum copper content does not exceed 0.40%. Or when the maximum prescribed level for any of the following items does not exceed the indicated percentages, or 1.65%. 100 for manganese, 0.60 p. 100 for copper and 0.60 p. 100 for silicon.

Applications and Properties of Carbon Steel in the Brazilian Metallurgical Industry


Usable in a variety of cost-effective metal forming techniques (especially pressing), carbon steel is used in a wide variety of applications. These materials combine ease of production and adequate strength, as well as excellent characteristics that provide a good surface finish.

Carbon Steel can be divided into two main groups: Low Carbon Steel and High Carbon Steel.

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Low Carbon Steel

High strength low alloy steel comprises a group of specified steels whose chemical composition has been specifically designed to provide superior mechanical properties, better weldability, hardness and, in the case of some steels, greater resistance to atmospheric corrosion than that which can be obtained with conventional carbon construction steels of equivalent strength. Sheets are generally intended for uses where their greater strength allows them to save weight.

The hardness or temper of cold rolled steel is determined by analysis, the volume of cold rolling or the application of a final annealing. These operations make it possible to obtain optimal mechanical properties for the forming operation, whether deep drawing, forming or flat cutting.

The skin pass treatment is a small reduction rolling after the annealing process to prevent the appearance of warping bands, which can ruin the appearance of the formed product.

Mild steels can only be hardened by hardening, as their carbon content is too low to cause significant heat treatment. However, they can be hardened to a harder surface.

Supply of Carbon Steel to Brazilian Industry

High Carbon Steel

Standard (heat treated) sheets are sheets that have been heat treated in an oven to homogenize and refine the grain structure. The aim of the treatment is to improve the steel's ability to resist brittle fracture at low temperatures of use.

Sheets are often indicated for bridge works , when the thickness of the sheets is relatively large or when the temperature of use is very low, or under both conditions. Other structures that commonly use standard carbon steel plates are icebreakers, external crane beams, and other structures subject to dynamic loads. This type of sheet must also be used to manufacture certain pressure vessels. For example, when ASTM A516 pressurized steel is used and the sheet thickness is greater than 1.5", or when the notch hardness properties have been specified by the design.


Rolled carbon steels with a bright finish are often used in the annealed state to form components which are then heat treated in batches to increase their hardness and elasticity characteristics.

To maintain a suitable surface, heat treatment must be carried out in a controlled atmosphere oven, at a temperature adapted to the quantity and quenched with oil to obtain maximum hardness.

Immersion must then be carried out to reduce the strength/hardness of the material but significantly improve its hardness and conductivity. Temperatures in the range of 300 to 450 °C should be used to achieve the desired final hardness. Alternatively, bainitic quenching is often performed in a molten salt bath at 350-450 °C.

Distribution and Supply of Carbon Steel for the Brazilian Metallurgical Industry

Hardened and Tempered

Hardened and tempered steel is processed into strip at the factory before being delivered to the customer. Many applications do not require extensive bending and forming and it is preferable in these cases to use tempered strips.

Main advantages:

  • no risk of distortion
  • Uniformity of surface finish
  • Constant mechanical properties
  • These factors often imply a reduction in machining costs and a better quality product.
  • Relaxation Annealing

After major deformation, the steel requires a low temperature annealing relaxation (250-300 °C) to fix the shape of the components. The metal will then have an oxidized color finish (blue bronze) which slightly improves corrosion resistance.