Cavitation Erosion Behavior of Unalloyed Carbon Steels and Morphology of the Eroded Microstructures

Research on the cavitation erosion behavior of carbon steels remains relatively limited, primarily because these materials are conventionally associated with structural applications involving moderate mechanical loading. Nevertheless, a detailed understanding of the response of this class of steels to the impact of shock waves and microjets generated by the implosion of cavitation bubbles is important for engineering applications. This is particularly relevant because components manufactured from carbon steels may operate under cavitating flow conditions characterized by different levels of erosive intensity. Typical examples include hydraulic-machine rotor hubs, valve bodies, hydraulic spools and seats, stator blades, and guide vanes. In this context, the present study investigates the vibratory cavitation erosion behavior of three hypoeutectoid carbon steels: S235J2 general-purpose structural steel, GS300 cast steel, and C15E quality carbon steel. The tests were carried out on the standard 20 kHz vibrating apparatus. The experimental procedure was carried out according to the laboratory’s custom, in compliance with the requirements of ASTM G32. The analysis of the characteristic cavitation erosion curves and parameters, together with macroscopic and microscopic investigations, reveals the superior cavitation erosion resistance of C15E steel, which is associated with its higher hardness, lower elongation at fracture and alloying elements Ni, Cr and Cu.