Development of an atmospheric controlled IH-FPP treatment system and its application to structural steel

An atmospheric controlled IH-FPP (Induction Heating and Fine Particle Peening) treatment system was developed. Using the system, the surface of ordinary structural steel was modified with Cr shot particle at room temperature, 500°C, 700°C and 900°C in atmosphere of either argon and air. The treated surfaces were characterized using a scanning electron microscope (SEM), an energy dispersive X-ray spectrometer (EDX), an X-ray diffractometer (XRD) and an X-ray photoelectron spectroscope (XPS). In the case of the specimen treated in argon atmosphere, a relatively thick and uniform Cr rich layer was formed at the surface. The thickness of the layer was changed with an increase in temperature, the higher the temperature, the thicker the layer. In the case of the specimen treated in air, however, an oxidized scale was formed on the treated surface instead of a Cr rich layer. The results of the experiments prove that atmospheric controlled IH-FPP treatment successfully creates a Cr rich surface layer. The specimen treated by atmospheric controlled IH-FPP showed higher corrosion resistance compared to that of the untreated specimen, the higher the thickness of the Cr rich layer, the higher the corrosion resistance.