Steels designed for the hardening of the surface layer
Carburized steels, with low carbon content, allow pieces to be obtained that, after the mechanical processing and carburizing treatment, combine a high surface hardness with good core toughness.
Thanks to the high surface hardness that can be obtained with the carburizing treatment, these steels are used to create those mechanical bodies for which a considerable surface hardness is necessary, such as gears, pins, bushes, shafts, and everything essential for the transmission of motion.
The versatility of the range of carburized steels allows a vast range of uses to be covered, from the most miniature gears to motor shafts of considerable size.
The heat treatments available for this type of steel – to be checked on a case-by-case basis according to the different qualities – are: rolled natural, workable annealed, isothermal annealed, globular annealed, normalized, and quenched and tempered.
Carbon-only steels for surface hardening steels do not contain particular alloy elements in addition to carbon. They are often tempered in water and are therefore only suitable for the production of pieces with simple shapes and applications that are not demanding, such as some pins and bushings.
The R10Pb type is offered in the version with the addition of lead, which facilitates machining by chip removal.
Steels with alloy elements for surface hardening contain some characterizing elements that confer different characteristics depending on the applications. After machining, carburizing and tempering, usually performed in oil, these steels have high surface hardness characteristics and exceptional core toughness.
The alloy elements (manganese, chromium, nickel, and molybdenum), added individually or in combination with each other, allow the types to be diversified to use the type best suited to specific needs.
The temperability increases with the increase of the alloy elements, and therefore it is possible to obtain core-transformed structures into increasingly larger pieces. In particular, chromium tends to increase the core hardness, while nickel improves toughness and resistance to impacts.
The complex of alloyed carburized steels available at Rodacciai allows a vast range of applications to be covered for pieces with sizes from small to consider.
Some of these steels are available in the leaded version, which facilitates machining by chip removal.
