The aim of this research was to investigate the effect of substrate fracture toughness and hardness on the load carrying capacity and impact wear resistance of coated three different tool steels, coated with three different hard PVD coatings: monolayer (TiAlN), multilayer (AlTiN/TiN) and nanocomposite ((Ti,Si)N). Hardness and fracture toughness of the substrate was varied using different combinations and parameters of vacuum heat treatment and deep cryogenic treatment, and effect on the load-carrying properties determined under progressively loading dry sliding conditions and impact wear test using ball-on-plate was investigated.As the most important feature hardness of the substrate was revealed, which affects both the load-carrying capacity and impact wear resistance of the coated surface. The increase in the fracture toughness of the substrate, although on the expense of the reduced hardness of substrate, it appears useful in coatings with increased hardness and brittleness.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 1125034The aim of this work was to determine the impact of various heat treatments on the HRc/ KIc ratio and subsequently on the impact wear properties of two coated (TiAlN) cold work tool steel and one high-speed steel. Powder metallurgy steels used as a substrate material were vacuum heat treated under six different conditions and combined with deep cryogenic treatment and nitriding with the aim to modify hardness and fracture toughness. It was shown that use of cryogenic treatment can increase fracture toughness from 10 and up to 67% while maintaining the same hardness for some cold work tool steels, when on others can have negative effect. Regarding the static load-carrying capacity, the most important feature of the substrate is its hardness, which at working hardness of 63-64 HRc already provides good static load-carrying capacity of coated substrate. Increased fracture toughness achieved by deepcryogenic treatment can at very high and/or very low hardness of the substrate have negative impact on the dynamic wear properties of the coated surfaces. On the other hand, in the case of vacuum heat treatment that ensures adequate working hardness of 63-64 HRc, deep cryogenic treatment improves impact wear resistance of coated surfaces.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 1184170Using different hard coatings in order to reduce friction and wear. Guidelines for the use and examples from practice
F.18 Transfer of new know-how to direct users (seminars, fora, conferences)
COBISS.SI-ID: 1124010The aim of this study was to investigate the influence of geometry and the sequence of surface texturing process on tribological properties of contact surfaces in fine blanking operation. Textures in the form of pyramid, cone and concave shape were introduced before and after hard TiAlN coating deposition. Textures with pyramidal shape resulted in the worst tribological behaviour, while laser textures provided the best results. It was found that the sequence of surface texturing has an effect on tribological behavior. If texturing is done after coating deposition, friction is lower regardless of the texturing type because of the better wettability of steel in comparison with coating. Even if coating is only cracked and delaminated in a cavity, this will result in lower friction coefficient.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 1196970