Effect of Hot-Dip Silicon-Aluminizing on the Anti-Carburization Behavior of High-Temperature-Resistant Steel HK40
High-temperature-resistant (HTR) austenitic steel HK40 is employed for being silicon-aluminized by being hot-dipped in molten aluminum and silicon alloys and diffused subsequently at 1200°C. The phases, microstructures and concentration for elements of interest in the treated case are investigated by x-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectrum of x-ray (EDS). The case composes of three main zones: the former hot-dipped coating zone, inter-diffusion zone, and diffusion zone of Al and Si, all of which contain quite higher contents of aluminum and silicon than substrate. Pack-carburization is used for assessing the anti-carburization behavior of the treated case. The treated case shows excellent property in hindering the inward-diffusion of carbon, even if the former hot-dipped coating zone spalls off with only diffusion zone left. High contents of aluminum, silicon and oxygen are still detected on surface of the silicon-aluminized specimen after carburization. Good anti-carburization ability of the silicon-aluminized specimen is believed mainly to be the result of the dense and stable Al2O3 and SiO2 films formed on the surface.
Jang Hyun Sung, Chan Gyu Lee, Yong Zoo You, Young Kook Lee and Jae Young Kim
F. Xie and J. Morral, "Effect of Hot-Dip Silicon-Aluminizing on the Anti-Carburization Behavior of High-Temperature-Resistant Steel HK40", Solid State Phenomena, Vol. 118, pp. 173-178, 2006