Wear Resistance Improvement of Cold Work Tool Steel by Fine Shot Peening

Surface modification using fine shot peen (FSP) comparing to and combining to hard film coating TiAlN-PVD on commonly used hardened cold work tool steel are studied in this research for their resistance to adhesive wear. Ball on disk tests were carried out to investigate the performances of those surface modification methods. In comparison to hard thin film coating, PVD-TiAlN coated tool was superior to FSP modified tool for its wear resistance. However, combining FSP and nitriding on TiAlN coated tool had higher wear resistance than that of TiAlN coating alone. Moreover various types of texture obtained from different FSP conditions were also investigated. The average roughness parameter (Ra) which is commonly used is not a good representative to determine the surface required for wear resistance enhancement for FSP. As Ra relates to the magnitude of the roughness profile only. The spacing parameters seem to be more effective. The larger the surface spacing after FSP, the higher is the wear resistance.