The solid particle erosion of pre oxidized high manganese nitrogen stabilized austenitic stainless steel (18Cr-21Mn-0.65N-Fe) at 400 to 700 °C

Abstract

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 (Cr2N) 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.