Failure analysis of two cylindrical impact pistons subjected to high velocity impacts in drilling applications

Top hammer drilling is a common method to drill holes in rock formations mining and civil engineering applications. Failure of machine components has significant impact on the cost period operation. Internal percussive hammers experience extreme loading conditions during their service life. The focus present case study characterize failure mechanisms two cylindrical pistons subjected loading. investigated were manufactured from different steel grades, surface hardened low alloyed high strength through cold work tool steel. both started with degradation surfaces term cavitation erosion localized fatigue phenomena. Subsequently, chipping removal material resulted formation semi-spherical craters surfaces. Radial hoop cracks develop cavities surface. radial then propagated parallel impacting longitudinal direction piston. Once formed at surface, damage was controlled by fatigue. Fatigue beach marks identified fracture failed component.