Application of carbide cutting tools with nano-structured multilayer composite coatings for turning austenitic steels, type 16Cr-10NI

This paper addresses the challenges of increasing the efficiency of the machining of austenitic stainless steels AISI 321 and S31600 by application of cutting tools with multilayer composite nano-structured coatings. The main mechanical properties and internal structures of the coatings under study (hardness, adhesion strength in the "coating-substrate" system) were investigated, and their chemical compositions were analyzed. The conducted research of tool life and nature of wear of carbide tools with the investigated coatings during turning of the above mentioned steels showed that the application of those coatings increases the tool life by up to 2.5 times. In addition, the use of a cutting tool with coatings allows machining at higher cutting speeds. It was also found that the use of a tool with multilayer composite nano-structured coating (Zr,Nb)N-(Zr,Al,Nb)N ensures better results compared with not only monolithic coating TiN, but also with nano-structured coatings Ti-TiN-(Ti,Al)N and (Zr,Nb)N-(Cr,Zr,Nb,Al)N. The mechanism of failure of the coatings under study was also investigated. © 2017 AFM, EDP Sciences

Development of modifying compounds for multilayer nano-structured coatings for cutting tools

The subject of this study was to research and develop modified multilayer nanostructured wear-resistant coatings (NWC) for cutting tools. NWC are formed through the innovation process of filtered cathodic vacuum-arc deposition (FCVAD). The processes of FCVAD allow forming NWCs by filtering vapour-ion flow of macro/micro particles in the plasma torch of vacuum arc, using the plasma duct of special structure isolated from the station chamber, when the angle of rotation of the plasma stream is 120°. This work presents the configuration of the system, alongside with the influence of process parameters on the output. The topology of the coatings is presented together with the hardness and a comparison between standard physical vapour deposition (arc PVD) and FCVAD coating technologies. Machining tests were undertaken in turning of standard HB200 steel and heat resistant nickel alloy. The results are presented in terms of tool flank wear. It is shown that the application of the NWC secured 2-6 fold extended tool lif

Effect produced by thickness of nanolayers of multilayer composite wear-resistant coating on tool life of metal-cutting tool in turning of steel AISI 321

The paper considers multilayer composite nano-structured Ti-TiN-(Ti,Al,Cr,Si)N coatings for metal-cutting tools. The coatings under the study mechanical characteristics of the coatings were studied, and the tool life tests were carried out for carbide tools with the above coatings for dry about 80 nm). The turning of steel AISI 321(HB 180) at vc = 100, 150, and 200 m/min (f=0.11 mm/rev; ap=0.5 mm). Uncoated tools and tools with Ti-(Ti,Al)N coatings of traditional type were used as objects of comparison. The studies have found out that coatings with thinner nanolayers demonstrate better performance properties, especially at higher cutting speeds. © 2018 The Authors. Published by Elsevier Ltd

Development and research of nanostructured multilayer composite coatings for tungsten-free carbides with extended area of technological applications

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. © 2016 Springer-Verlag Londo

Improvement of structure and quality of nanoscale multilayered composite coatings, deposited by filtered cathodic vacuum arc deposition method

This article studies the specific features of cathode vacuum arc deposition of coatings used in the production of cutting tools. The detailed analysis of the major drawbacks of arc-Physical Vapour Deposition (PVD) methods has contributed to the development of the processes of filtered cathodic vacuum arc deposition to form nanoscale multilayered composite coatings of increased efficiency. This is achieved through the formation of nanostructure, increase in strength of adhesion of coating to substrate up to 20%, and reduction of such dangerous coating surface defects as macro- and microdroplets up to 80%. This article presents the results of the studies of various properties of developed nanoscale multilayered composite coating. The certification tests of carbide tool equipped with cutting inserts with developed nanoscale multilayered composite coating compositions in longitudinal turning (continuous cutting) and end symmetric milling, and intermittent cutting of steel C45 and hard-to-cut nickel alloy of NiCr20TiAl showed advantages of tool with nanoscale multilayered composite coating as compared to the tool without coating. The lifetime of the carbide inserts with developed NMCC based on the system of Ti-TiN-(NbZrTiCr)N (filtered cathodic vacuum arc deposition) was increased up to 5-6 times in comparison with the control tools without coatings and up to 1.5-2.0 times in comparison with nanoscale multilayered composite coating based on the system of Ti-TiN-(NbZrTiCr)N (standard arc-PVD technology). © The Author(s) 2017

Development of wear-resistant coatings compounds for high-speed steel tool using a combined cathodic vacuum arc deposition

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

Nano-scale multi-layered coatings for improved efficiency of ceramic cutting tools

This paper considers improving the efficiency of ceramic cutting tools using nano-scale multi-layered composite coatings deposited with an innovative arc-PVD processes with filtration of vapour-ion flow and diamond-like coating (DLC). Here a three-layered architecture of nano-structured multi-layered composite coatings is used, and the wear mechanism of the ceramic tool is examined. This approach allows implementing a direct control over the contact characteristics of the cutting process in order to reduce the normal and shear stresses that increase the probability of tool failure as a result of brittle fracture. This increases the adhesive strength of the coating with respect to the ceramic substrate. This resulted in an increase in tool life with reduced failure rate because of brittle fracture of the cutting edge. © 2016 Springer-Verlag Londo

Delamination and longitudinal cracking in multi-layered composite nanostructured coatings and their influence on cutting tool life

This paper presents the results of a study of the mechanisms of delamination and the formation of longitudinal cracks in the structure of multi-layered nano-structured coatings to predict the mechanisms for further improvement of tool life and the reliability of metal-cutting tools. Various mechanisms of formation of longitudinal cracks and delaminations in coatings on rake and flank tool surfaces, which vary based on the compositions and architectures of the coatings, are addressed. In addition, the influence of internal defects, including embedded microdrops and pores, on the formation of cracks and delaminations and the failure of coatings is discussed. The importance of ensuring a balance of the basic properties of coatings to achieve high wear resistance and maximum tool life of coated metal cutting tools is shown. The properties of coatings and the natures of their failures, as investigated during scratch testing and dry turning of steel C45, are provided

Main Ways to Improve Cutting Tools for Machine Wheel Tread Profile

This chapter considers the methods to increase the performance and reliability of the reprofile machining of the wheel tread profile. Proceeding from the fact that both in milling and turning, the cutting tool is a key element to ensure performance and reliability of the manufacturing process, the study considers the methods to increase the performance properties of cutting tools. In particular, the study includes the investigation of the following ways to improve cutting tools (carbide inserts) to machine wheel tread profile: replacement of traditional grades of WC-TiC-Co carbides with more efficient ones based on WC-TiC-TaC-Co; application of special thermally conductive pads, gaskets, and pastes to improve the distribution of heat flows in the cutting zone; and application of modern nanoscale composite multilayer coatings (NMCC). It is noted that even higher performance can be obtained by combining the above three methods, in particular, by combining application of special thermal pads and NMCC

Delamination and Longitudinal Cracking in Multilayered Composite Nanostructured Coatings and Their Influence on Cutting Tool Wear Mechanism and Tool Life

The wear and failure mechanism for multilayered nanostructured coatings has a number of significant differences from the one typical for monolithic single-layered coatings. In particular, while the strength of adhesion bonds at the “substrate-coating” boundary is important for monolithic coatings, then for multilayered nanostructured coatings, the strength of adhesion and cohesion bonds at interlayer boundaries and boundaries of separate nano-sublayers becomes of significant significance. Meanwhile, the delamination arising in the structure of multilayered nanostructured coatings can have both negative (leading to loss of coating uniformity and subsequent failure of coating) and positive influences (due to decrease of internal stresses and inhibition of transverse cracking). Various mechanisms of formation of longitudinal cracks and delaminations in coatings on rake tool faces, which vary based on the compositions and architectures of the coatings, are studied. In addition, the influence of internal defects, including embedded microdrops and pores, on the formation of cracks and delaminations and the failure of coatings is discussed. The importance of ensuring a balance of the basic properties of coatings to achieve high wear resistance and maximum tool life of coated metal-cutting tools is shown. The properties of coatings and the natures of their failures, as investigated during scratch testing and dry turning of steel C45, are provided