Cold spray repair of cavitation damages on hydropower components: impact of the deposition process and cavitation resistance benchmarking

With the emergence of sustainable manufacturing concept, repair of near end-of-life structural components has become increasingly relevant or even critical in many industrial sectors. As such, there is a strong interest for fast and cost-effective solutions to extend the lifetime of large metallic parts. In the case of hydropower components made of steel, cold spray represents a promising solution for the repair of cavitation damages. The capability to rebuild metallic surfaces without affecting the base material gives cold spray a clear edge over the current welding repair techniques, which could lead to significant cost savings.

In this presentation, we will disclose the results of our investigation on the properties and performance of cold sprayed 1025 carbon steel, 316 & 309 austenitic stainless steels, and Cavitec alloy (TRIP-type alloy specifically developed for protection against cavitation damages) deposited with nitrogen. A thorough analysis of powder characteristics, cold sprayability of these materials, deposit microstructure, XRD phase analysis and cavitation resistance will also be presented, and correlations between cavitation results and deposit properties will be discussed. Finally, cavitation resistance of the cold spray deposits, with and without heat treatment, will be benchmarked versus bulk materials.