Effect of different operating parameters on the slurry erosion behavior of cryo-treated hydro-turbine steel

Abstract

In the present research work, various aspects such as formulation, experimentation and analysis have been covered to examine the effect of operating parameters on the slurry erosion behavior of cryogenically treated hydro-turbine steel. To obtain this objective, two different cryo-treatments viz. Shallow and Deep cryo-treatments were performed on the steel. The micro-structural characterization of the un-treated and cryo-treated samples was performed by scanning electron microscope, energy dispersive spectroscopy and X-ray diffraction techniques, whereas micro-hardness was conducted using Vickers hardness method. The slurry erosion tests were performed on the un-treated and cryo-treated steel samples using specifically contrived jet type slurry erosion test rig. Later, the effects of distinct operating parameters viz. slurry concentration, average particle size and impact velocities on the slurry erosion were explored. It was inferred that the cryogenically treated samples offer more resistance against slurry erosion than the un-treated samples. The increase in wear resistance was related to the microstructure of cryogenically treated samples. SEM and X-ray diffraction analysis of the cryogenically treated samples revealed the revamping of retained Austenite into Martensite and refinement of crystal-structure after Cryogenic treatment, which improves the wear resistance.