They are steels that by their properties, after quenching and tempering, are suitale for the manufacture of springs. They have a high yield strength, which allows them to support defined loads, without presenting permanent deformation after removal of the load.
These steels have high Carbon content and alloying elements such as Silicon, Manganese, Chromium, Molybdenum and Vanadium.
Their most common applications are springs, fixed keys, chisels, sickles, shears, wire cutting scissors, torsion bars, straps and two-leaf keys.