Oxidation of silicon steels

Abstract

The oxidation behaviour of a series of high silicon steels was studied by means of optical microscopy and scanning electron microscopy. The samples were cast with amounts of silicon that ranged from 3.3 to 11.6 wt-%. The experimental samples were cut from the ingots, polished and cleaned before placing them in an electric furnace at temperatures that varied from 1000 to 1230°C for a total time of 50 min. Specimens were then mounted and polished for examination. The analysis of X-ray spectra taken in different regions of the oxide crust indicated the presence of different oxide species. It was found that growth of the layer depended on the temperature at which the treatment was made, and on the amount of silicon in the steel, as it was found that the diffusion of silicon to form fayalite reduced the rate of growth.