Comparison of FeMnCrSi Cavitation Resistance Coatings Deposited by Twin-Wire Electric Arc and High-Velocity Oxy-Fuel Processes

摘要

The hydraulic runners and many other components are exposed to cavitation phenomena and the erosion occurs, and normally are repaired by arc welding processes. However, the heat input from the welding causes microstructural changes in the components materials. Considering the martensitic stainless steel CA6NM, the welding thermal cycle reduces its fracture toughness and consequently the structural integrity of the equipment. Thermally sprayed coatings are an alternative to repair low eroded areas of these components, since the thermal sraying processes do not change the substrate microstructure and/or mechanical properties as the welding process. Different FeMnCrSi alloys deposited by Twin-Wire Electric Arc (TWEA) or High-Velocity Oxy-Fuel (HVOF) are on development and their cavitation resistance, comparable to the substrate CA6NM, are the object of the study in this research. This work presents the comparison of the deposition characteristics and properties of different FeMnCrSi alloys chemical compositions coatings obtained by TWEA and HVOF processes, evaluating the particles in-flight, morphology, hardness, adherence, and cavitation resistance of the coatings.