This article presents the work on wear-resistance coatings (WRC), formed on the working surfaces of HSS tools, in order to increase their efficiency. The wear-resistant complex includes nitride ...layer, which increases the plastic strength of the HSS tool cutting wedge and cutting tool wear resistance, as well as a three-layer nano-structured composite coating that increases tool life. The equipment for the processes of ion nitriding in the gas plasma and the formation of nano-structured multi-layer composite coatings in the filtered metal-gas plasma cathode vacuum arc discharge has been developed. Particular attention was paid to the regularities in the formation of the nitride layer and optimization of its parameters and structure, together with the study of the properties and structure of functional coating layers, depending on the parameters of the deposition process. The parameters of the combined cathodic vacuum arc processing (CCVAP), provides minimum intensity of tool wear during the cutting tests. Sample of coated tools were used to conduct a certification of the developed WRC. This allowed determining the optimal parameters WRC that provided the maximum increase in tool life for a variety of cutting conditions. The outcomes are compared with uncoated HSS tool and standard commercial coatings.
This paper discusses aspects of the development of nanostructured multilayer composite coatings (NMCCs) formed using the processes of filtered cathodic vacuum arc deposition (FCVAD) for application ...to the tungsten-free carbides (cermets) based on TiC-(Ni,Mo) and TiCN-(Ni,Mo) compounds in order to improve cutting properties of tools and to expand the area of their technological application. NMCCs were used not only to improve the physical and mechanical properties of the working surfaces of tools but also to ensure the control over contact processes during cutting. The study has shown that despite their high hardness, thermal stability and resistance to scaling, low tendency to diffusion with the material being machined, and tungsten-free carbides are characterized by relatively low fracture toughness and bending strength, low thermal conductivity. With regard to the above properties, tungsten-free carbides are inferior not only to tungsten WC-Co carbides but also to WC-TiC-Co carbides with binder content of less than 8 % (by weight). Therefore, cutting tools made of tungsten-free carbides have a limited range of technological application in interrupted cutting, machining of hard-to-cut alloys and steels. With respect to this, the paper considers the possibility of directional control over contact processes during cutting with the use of NMCCs to create more balanced properties of tungsten-free carbides with regard to hardness and toughness. This work has developed architecture of three-component nanostructured multilayer composite coatings, the methods for selecting functions and rational component parameters of architecture for tools made of tungsten-free carbides. The developed compositions of NMCCs have improved cutting properties of tungsten-free carbides and expanded the area of their technological application in cutting of heat-treated steels of increased hardness and machining of heat-resistant alloys.
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