Tribology study on 27Cr-7Ni-Mo-W-N cast hyper duplex stainless steel (7A) at room temperature

Hyper duplex stainless steel (7A) was casted in induction furnace and heat treated at 1150 °C and 900 °C. Heat treatment temperatures were determined with the help of Computational thermodynamic (Thermocalc) software. Sensitization of hyper duplex stainless steel was achieved at 900 °C and the same was confirmed from the hardness and microstructures. To study the erosive behaviour of hyper duplex stainless steel, air jet erosion was carried out at room temperature with the angle of impingement at 45°. Identify the intermetallic compounds which was precipitated at 900 °C, scanning electron microscope (SEM) and energy dispersive analysis spectroscopy (EDS) was carried out on the eroded samples. Erosion mechanism was explained on two different heat treated samples and the results are clearly explained that sensitized sample have less erosion than the solutionized samples which was heat treated at 1150 °C due to the high hardness on the sensitized samples because of the intermetallic phases.