About the interrelation between carbon content in steels and the martensite hardness

The hardenability of steels, identified by the interrelation between carbon content and available maximum hardness in a full martensitic microstructure is important for decision in case of steel selection and optimal construction of components. In the industrial practice formulas for calculation were used, deduced from the classic statements of Hodge/Orehoski and Burns/Moore/Archer. But the calculated results are significantly different. For a more exactly view datas of the "Atlas zur Wdrmebehandlung der Stahle" were used. The better results are to expect by using the formula of Just. The application is also important for case hardening. It can be concluded that a lower carbon content than 0,35 mass-%, the value usual is used, is sufficient to arrive a limit hardness of 52.5 HRC or 550 HV for determination of the case hardening depth. This confirms with the investigations of the AWT-FachausschuB 5/AK4. There has been found a formula of interrelation between carbon content and martensite hardness that gives a curve identical with the curve from Burns/Moore/Archer.