An investigation on the suitability of different surface treatments applied to a DIN X100CrMoV8-1-1 for cold forming applications

In this work DIN X100CrMoV8-1-1 cold work tool steel samples were plasma nitrided and coated with two different films TiCN and AlCrN by plasma-assisted physical vapor deposition with cathodic arc evaporation method. The samples were characterized concerning surface roughness, chemical composition profile by Glow Discharge Optical Emission Spectroscopy (GDOES), hardness profile, coating thickness, coating adhesion, present phases and residual stresses. Friction coefficient and wear rate were measured by carrying out pin-on-disk tests. Furthermore the developed surface treatments were applied to cutting punches and industrial tests were carried out. Surface conditions (nitrided or not) prior to PAPVD did not affect roughness after coating, but coating adhesion was improved. Compressive residual stresses were increased on the previously plasma nitrided substrates when compared to those on the non-treated ones, and plasma nitriding also resulted in better load bearing capacity. Results also showed that AlCrN and the duplex AlCrN didnʹt present the running-in behavior as seen for TiCN and duplex TiCN. It was also possible to assure that the combination of plasma nitriding and the TiCN hard coating on top gave the best coating adhesion and the lowest wear rate, what is reflected on the cutting punches analysis after real industrial use.