An experimental study to corelate water jet impingement erosion resistance and properties of metallic materials and coatings

This paper describes the water jet impingement erosion characteristics of titanium alloy (Ti6Al4V), Hadfield steel, laser hardened, plasma nitrided and pack borided 12Cr steel along with most commonly used steels in hydro turbines. Round samples as per ASTM G73-98 were tested for water jet impingement erosion study. While testing, in the incubation period, plasma nitrided and pack borided 12Cr steel performed much better than 12Cr and 13Cr4Ni steels. Plasma nitrided 12Cr steel performed much better than pack borided 12Cr steel. This is due to the integrity of plasma nitrided layers and their ability to absorb shocks due to jet impingement. During incubation as well as in the long run, Hadfield steel and laser hardened 12Cr steel performed exceptionally well followed by 17Cr4Ni ‘PH’ steel. Based on this experimental study, a suitable criterion based on ultimate resilience (UR) for metallic materials and a composite modified resilience (CMR) for hard metallic coatings has been discussed. Water jet impingement erosion test results along with the mechanical properties of materials and coatings, and their scanning electron microstructural details are reported in this paper.