CARBON STEELS (C18 - C23 - C35)



Steel is an alloy composed of iron and carbon, that is not more than 2,06% (over this limit, the properties of the material change and the alloy gets the name of “cast iron”). The presence of other elements in the alloy, such as manganese, chromium, vanadium, cobalt, etc. can alter the steel’s characteristics.

Steels follow the nomenclature defined by the 2006 UNI EN 10027 norm that defines two different systems of nomenclature: alphanumeric and numeric. Other two important nomenclature systems are AISI and ASTM American systems. Specifically, steels with carbon content included between 0,15% and 0,40% are defined “mild steels”. These are typically used in the screw production.


  • Content of carbon included between 0,15% and 0,40%.
  • Tensile strength can vary between 480 and 1100 MPa (4898 – 11224 Kg each cm2).
  • Easily worked with plastic deformation and cold elaboration.
  • They can be hardened through thermal treatments that confers mechanic properties.
  • They can also be finished on the surface through different treatments as carbonatization or hardening that improve the mechanic properties of the surface.
  • They can also have different superficial upholstery to improve aesthetic characteristics or corrosion resistance as Lantane® coating, lacquering or painting.
  • Magnetic and electric conduction properties.
  • Easily weldable.


In 2018 UBB produced a zinc-plated self-tapping screw with bombed wide head and hexagon socked in steel to be hardening 6,3x15 with thermal treatment of carbonatization and superficial Lantante white coating Fe/Zn 3c1A Cr 3 + dehydrogenation.