Induktive Randschichtnachbehandlung zur Steigerung der Korrosionsschwingfestigkeit des Radsatzwellenwerkstoffes EA4T Inductive surface layer treatment to increase the corrosion fatigue strength of the wheelset shaft material EA4T

Wheelset shafts are usually coated to protect them from mechanical and corrosive influences. However, damage during operation requires close inspection intervals to check permissible damage depths. The focus of this research is to investigate a possible increase in corrosion fatigue strength through inductive surface layer treatment for the wheelset shaft material EA4T (25CrMo4+quenched and tempered). For this purpose, process parameters for inductive surface hardening were identified and optimized in order to achieve a sufficiently high hardening depth and hardness of the surface layer on lightly notched test specimens. Subsequently, fatigue strength tests were carried out in air and in 5 % NaCl solution for the initial state and the hardened state. By comparing the fatigue strength results determined, the expected potential for increasing fatigue strength and corrosion fatigue strength was confirmed. In order to demonstrate stone chipping and corrosion stress, further tests were repeated with damage specifically introduced into the surface layer. The findings indicate the potential of surface layer hardening for significantly lower-maintenance wheelset shafts in freight transport in the future.