Ž . Wear 233–235 1999 86–92 www.elsevier.comrlocaterwear The influence of residual stresses on cavitation resistance of metals — an analysis based on investigations of metals remelted by laser beam and optical discharge plasma Boleslaw G. Giren a, ) , Marek Szkodo b , Janusz Steller a ´ a Institute of Fluid-Flow Machinery, Polish Academy of Sciences, 80-952 ul. Fiszera 14, Gdansk, Poland ´ b Mechanical Department, Technical UniÕersity of Gdansk, 80-952 ul. Narutowicza 11, Gdansk, Poland ´ ´ Abstract An analysis of the changes of residual stresses in metals as well as analysis of their performance under cavitation conditions contributed to enlight the problem of the influence of residual stresses on metal resistance to cavitation attack. The samples destined for testing were processed superficially with c.w. CO laser beam or an optical discharge plasma; afterwards they were subjected to 2 cavitation erosion in the rotating disk facility. Residual stresses were determined by interferometric methods. q 1999 Elsevier Science S.A. All rights reserved. Keywords: Cavitation erosion; Optical discharge; Laser processing 1. Introduction The search for new methods of material protection against cavitation erosion should be linked with the search for solid state structural features responsible for cavitation resistance. Laser radiation is known to produce conditions of ex- treme non-equilibrium at the targeted solid surface thus enabling production of alloys, structures and residual stress fields unattainable by other means. The encouraging results of laser beam application for creation of cavitation resistant coatings are reported, e.g., w x in Refs. 1–3 . To make the first step towards resolving the problem of residual stresses’ influence on the cavitation resistance of materials, the samples of 0.45% carbon steel and 13% chromium steel, acid-resistant chromium–nickel steels, low alloy manganese structural steels and copper alloys were superficially processed by a CW CO laser beam and 2 Ž . continuous optical discharge COD plasma. Afterwards, the workpieces were subjected to the process of cavitation erosion in a rotating disk facility. The aim of the investigations carried out was to verify the thesis that residual stresses are of considerable signifi- ) Corresponding author. Tel.: q48-583416144; fax: q48-583460881; E-mail: steller@imppan.imp.pg.gda.pl cance for cavitation resistance of the materials. It was proved by tracing the cavitation resistance of materials processed by laser beam with and without COD plasma. It was also assumed that completed observations should al- low to draw conclusions on the usefulness of COD plasma Fig. 1. The workpiece processing with the COD plasma. 0043-1648r99r$ - see front matter q 1999 Elsevier Science S.A. All rights reserved. Ž . PII: S0043-1648 99 00200-8