Quenched and tempered steels
Technical data sheets for quenched and tempered steels
Definition and applications
Quenching and tempering steels are a particular category of structural steels intended for quenching and tempering (normalization treatment is required for unalloyed grades). The special chemical composition of quenched and tempered steels has been specifically created to ensure the best performance after undergoing the quenching and tempering treatment. It consists of two stages of heat treatment: hardening and tempering, which give the pieces a particular hardness and tenacity, making them suitable for use in even the most severe conditions. . As a result, these steels are used for the construction of mechanical parts which are subjected to static and dynamic loads: all types of shafts, drive shafts, rods, connecting rods, bolts, connecting parts, hammer stems, press columns, supports and levers.
This group includes all types of structural steels that are to be quenched and tempered, i.e. which will undergo massive hardening followed by adequate tempering.
When the steel has only been hardened, it takes on an extreme toughness with very low tenacity: it is therefore necessary to temper the steel in order to eliminate all the fragility and tension. Indeed, this process gives the pieces a particular toughness and tenacity, making them suitable for use in even the most severe conditions and reaching a compromise between tenacity/toughness and resilience.
The tempering process is generally carried out on pieces that have reached the final stage of production, after most of the mechanical treatments. In this case, the semi-finished raw material can be supplied in its natural state of being workable as rolled or annealed, depending on the type of steel.
|Steel quality||Standard||Processing routes||Supply status||Rounds (mm)||Squares (mm)||Flats (mm)||Blooms* (mm)|
|C43||UNI 7847||Centerless ground||Natural||10-100|
|C45||EN 10083||Hot rolled||Natural||110-320||20-170||40×15-160×60|
|C45||EN 10083||Hot rolled||Hardened and tempered||110-200|
|42CrMo4||EN 10083||Hot rolled||Hardened and tempered||30-320||100-600**|
|42CrMo4||EN 10083||Forged||Hardened and tempered||320-600|
|39NiCrMo3||EN 10083||Hot rolled||Hardened and tempered||18-320||32-150||50×15-150×80||100-600**|
|39NiCrMo3||EN 10083||Centerless ground||Hardened and tempered||20-100|
|39NiCrMo3||EN 10083||Forged||Hardened and tempered||300-800|
|39NiCrMo3||EN 10083||Rolled||Soft annealing||18-220|
|39NiCrMo3Pb||(EN 10083)||Rolled||Hardened and tempered||18-200|
|40NiCrMo7 (34CrNiMo6)||UNI 7845 (EN 10083)||Rolled||Soft annealing||65-200||200-400|
|34NiCrMo16 36NiCrMo16||UNI 7845 EN 10083||Rolled||Annealed||30-150||200-400|
* Blooms: Supply status “natural”
** Available also 720×60