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Nitrogen stabilized austenitic stainless steel exhibits better combination of mechanical properties and corrosion resistance as compared to the conventional nickel containing 316L SS. It is a cost-effective replacement of conventional 316L SS used in various applications where air jet solid particle erosion is observed. This paper presents the erosion behavior of pre oxidized nickel free nitrogen stabilized austenitic stainless steel (18Cr-21Mn-0.65N-Fe) at four different temperatures. The stainless steel was first air oxidized for 100 h at 400, 500, 600 and 700 °C and then subsequently subjected to solid particle erosion at 400, 500, 600 and 700 °C respectively with particle velocity of 100 m s −1 . The erodent discharge rate was maintained at 4.6±0.5 gm min −1 and three impact angle 60°, 75°, and 90°were employed. Optical microscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and x-ray Diffraction technique (XRD) were used to characterize the eroded surface. Tensile tests and microhardness were performed to better understand the erosion behavior. The erosion rate increased steadily upto 500 °C, and there was an exponential increase at 600 and 700 °C. It is found to be associated with a decrease in the tensile strength and hardness of the steel. High temperature oxidation (preaging) resulted in the precipitation of harmful chromium nitride (Cr 2 N) which has accelerated the erosion rate at 600 and 700 °C. The alloy exhibited better erosion resistance at 90°impact angle compared to 60°and 75°. The main mechanism of erosion was ploughing, indenting, delamination and pitting. RECEIVED

This study presents the prehot corrosion effect on erosion behavior of AISI 446 SS in simulated heat exchanger environment at elevated temperature. Samples were spray deposited using two salt mixture (Na2SO4/NaCl). Subsequently, low-temperature hot corrosion tests were carried out at 550, 650, and 750 °C for 20 h. Chlorination followed by sulfidation was mainly responsible for the passive layer formation during the process of hot corrosion. The prehot corroded samples were subjected to air-jet erosion test using alumina as the erodent, at impact velocity of 100 m/s and flux rate of 4.2 g/min, with variable impingement angles of 30 deg, 60 deg, and 90 deg. The passive layer formed during corrosion underwent detachment of metallic flakes through cracking during the impact of erodent, and was responsible for a significant change in erosion rate. Cutting, plowing, lip formation, and particle embedment were identified as the operative mechanisms during erosion.