Surface modification of carbon steel by atmospheric-controlled IH-FPP treatment using mixed chromium and high-speed steel particles

First, in this paper, a new atmospheric-controlled induction heating and fine particle peening treatment system (vacuum AIH-FPP system) which reduces the oxygen concentration in the chamber to the order of ppm, much less than a conventional processing apparatus was presented. Next, in order to examine the effect on the formation of the surface modified layer of (i) mixing hard particles, (ii) the processing temperature, and (iii) the particle velocity, carbon steel AISI 1045 was treated with this system in conjunction with high-frequency induction heating, by peening Cr particles and mixed particles of Cr and high-speed tool steel. From the observation results by a scanning electron microscope and an energy dispersive X-ray spectrometer, it is clear that for the formation of a Cr diffused layer, using a mixture of Cr particles and high-speed tool steel particles is important. The treatment must be conducted at a higher temperature of approximately 1273 K to form a Cr diffused layer. Furthermore, by increasing the particle velocity, a thicker Cr transfer layer is formed at the surface under process. Therefore, an increased particle velocity accelerates the transfer of Cr.