Erosion visualisation and characteristics of a two dimensional diffusion treated martensitic stainless steel hydrofoil

Abstract

Erosive wear of complicated water pump and hydro turbine blades is a complex problem. This is due mainly to the many variables involved in the erosive wear. These depend upon type of erodant, base material and flow conditions. In this paper, visualisation and prevention of erosive wear on two dimensional forged 12Cr and 13Cr4Ni cast steel hydrofoils under flow conditions similar to that of hydroturbines and water pumps is described. An experimental study was taken using a rotating disc apparatus. From the study, it was observed that the erosion of complicated hydrofoils depends on the flow conditions, especially flow separation, reattachment and boundary layer growth. The visualisation of wear on the hydrofoils was obtained from the wear replicas which were etched on the aluminium rotating disc. Further, to control the wear of these hydrofoils, these were given a hard diffused layer based on boronizing. The performance of these hard diffused layers along with wear prediction on 12Cr and 13Cr4Ni steel hydrofoils are reported in this paper.