Metallographic studies results of 20kH13 steel samples with textured relief, modified surface and protective coating

Abstract

One of the possible ways to improve passive methods of the steam turbine blade material protection from water droplet erosion is to create “smart”-surface that combines the properties and characteristics that could not be implemented simultaneously when using one or another proven method of protection. To solve the problem of developing such surface, this article presents the metallographic researches results of the blade steel 20kH13 samples with various already used and promising passive methods of protection, consisting in the use of ion-plasma and polyurethane coatings, surface modification by means of diffusion saturation with nitrogen ions, creation of the structured surface relief by laser ablation. The results of the carried out researches have allowed to reveal both morphology of a possible “smart”-surface, and influence on a microstructure and characteristics of a near-surface layer of samples after treatments considered.