1.6566 | 17NiCrMo6-4 carburized with direct hardening
| Numeric designation | 1.6566 |
|---|---|
| Chemical designation | 17NiCrMo6-4 |
| State | carburized with direct hardening |
| Etching | 3 % Nital |
In direct hardening, the austenitizing temperature of approx. 780 °C in the carburized rim leads to a martensitic microstructure. In the core, due to the lower carbon content (which would require a higher austenitizing temperature), an incompletely hardened microstructure of bainite, ferrite and martensite is formed (average core hardness approx. 330 HV1, CHD approx. 1.5 mm).
