Preparations of effect of heat treatment on the isothermal oxidation of Fe-33Ni-19Cr

Abstract

The effect of heat treatment on the isothermal oxidation of Fe-33Ni-19Cr alloy were investigated at temperature 850°C for 150 hours. The samples of Fe-33Ni-19Cr was given in a square plate shape was undergone heat treatment of three different temperatures namely 1000oC, 1100oC and 1200oC. The heat treated sample was then grind until 600grit of SiC paper. Before oxidation test, each of the samples were weighed and measured by using analytical balance and vernier calipers. After that, the heat-treated Fe-33Ni-19Cr alloys were isothermally oxidized at 850oC for 150 hours. The morphologies of Fe-33Ni-19Cr alloy was characterized by scanning electron microscope. While the phase composition and intensity was determined by X-tray diffraction. In the other hand, the hardness test for this supper alloy was done by macro Vickers hardness machine. As a consequence, the average grain size will increased as the temperature of heat treatment increased. For mechanical properties, the hardness value will decreases as the temperature increases. While the result of surface morphologies shows that the lowest temperature which is 1000oC shows uniform oxide layer formed on the surface, while alloy heat-treated at 1200oC indicated oxide spallation. Next, phase analysis result shows that the oxidized sample formed several oxide phase.