Zerstörungsfreie Bestimmung der Einhärtungstiefe nach dem Randschichthärten mit mikromagnetischen Prüfverfahren. Beispiel: Laserhärten
According to DIN 50190 the hardening depth of surface hardened components is defined as the distance to surface characterized by a definite value of hardness (f.i. 550 vickers hardness HV). This hardness is usually determined by a microhardness test which requires a preparation and thereby a destruction of the component. Micromagnetic testing techniques like the magnetic Barkhausen noise method can be used for a nondestructive determination of hte hardening depth. These techniques are based on the interaction between magnetic domain walls and the microstructure of a ferromagnetic material. During dynamical magnetization of the material testing informations sensitive to microstructure and residual stress can be evaluated to estimate the machining quality of surface hardened components. Besides the hardening depth and the surface hardness the residual stress distribution is another relevant quantity to describe the surace hardening quality. The nondestructive determination of these quant ities by using micromagnetic techniques is described on laserhardened components.