Ultrasonic cavitation erosion of a duplex treated 16MnCr5 steel

Ultrasonic cavitation experiments using a piezoceramic-based apparatus, according to ASTM G32-2010, were performed on heat and thermochemically treated Cr – Mn low alloyed steel samples. The microstructure in annealed, carburized and tempered states as well as following a duplex treatment (carburized, surface induction hardening and tempering) was analyzed before and after the cavitation erosion tests. The results show the advantage of the duplex treatment, with a significant increase of up to 20 times of the cavitation erosion resistance compared to the annealed state and reveal that the main mechanism for surface deterioration is micro-cracking. The observations are important for the improvement of the behaviour for parts used in hydraulic equipment, for which the volume hardening following the carburization can be replaced by cost-efficient surface induction hardening treatments.