Surface Modification of EN 8 Steel by Aluminizing and Nitriding for Automotive Applications

The study deals with the surface modification of EN 8 steel by hot dip aluminizing and nitriding, for improving the surface characteristics. The microstructure, microhardness and wear of aluminized, diffused and nitrided (ADN) steel were studied. The studies were conducted based on Taguchi techniques in order to reduce the experimentation efforts. The surface hardness of ADN steel was increased to a maximum of 1200 Hv_0.1. X-ray diffraction studies have confirmed the presence of aluminium nitrides in the surface layer which is instrumental for the significant increase in hardness. The wear resistance of ADN steel is high compared to the base metal (BM) and it also has the lowest coefficient of friction. The process parameters were optimized based on the experiments. This could be used for automotive piston rings, where wear is critical.