Defects in chemical vapour deposited coatings on cemented carbide cutting tools

1997 ◽  
Vol 52 (6) ◽  
pp. 38-39
Keyword(s):  
Cutting Tools ◽  
Chemical Vapour ◽  
Cemented Carbide

Influence of Cup Wheel Grinding and Etching Pretreatment on Residual Stress and Surface Topography for Coated Cemented Carbide Tools

2012 ◽  
Vol 497 ◽  
pp. 10-14
Author(s):  
Tie Jun Song ◽  
Zhi Xiong Zhou ◽  
Wei Li ◽  
Ai Min Tang
Keyword(s):  
Residual Stress ◽  
Surface Topography ◽  
Cutting Tools ◽  
Wheel Speed ◽  
Cemented Carbide ◽  
Machining Process ◽  
Grinding Wheel ◽  
Near Surface ◽  
Cup Wheel ◽  
Coated Cemented Carbide

Cup wheel grinding and etching pretreatment are widely used in complex coated cemented carbide cutting tools machining process. The two processes determine different surface properties due to various mechanical and thermal loads in grinding and complex chemical reaction in etching pretreatment. In this paper, the effect of the grinding wheel speed, the grinding feed rate and the etching time with the Murakami and acid solution on the residual stress and surface topography of coated cemented carbide cutting tools are investigated. After each process, the samples are characterized by scanning electron microscopy and X-ray diffraction. It is found that the grinding wheel speed has a significant influence on residual stress measured in the WC phase. Etching by Murakami generated smooth surface, which partly removed the near-surface residual stress quickly but cannot eliminate.

Characterisation of Chemical Vapour Deposited AlHfN Coatings

2020 ◽  
Vol 405 ◽  
pp. 33-39
Author(s):  
Elisabeth Rauchenwald ◽  
Mario Lessiak ◽  
Ronald Weissenbacher ◽  
Sabine Schwarz ◽  
Roland Haubner
Keyword(s):  
Electron Microscopy ◽  
Protective Coatings ◽  
Cutting Tools ◽  
Chemical Vapour ◽  
Gas Composition ◽  
X Ray Diffraction ◽  
Multilayer Systems ◽  
X Ray ◽  
Transmission Electron ◽  
Hcl Gas

Chemical vapour deposited HfN can be utilised as a component of multilayer systems in protective coatings on cutting tools. In this study, related AlHfN coatings were synthesized through a reaction of metallic hafnium and aluminium with HCl gas forming gaseous HfCl4 and AlCl3, which were subsequently transported into a heated coating reactor. Via high temperatures and separately introduced NH3 and N2 as reaction gases, AlHfN coatings were deposited on hardmetal inserts. By varying the ratio between AlCl3 and HfCl4, compositionally different AlHfN coatings were examined. Additionally, surface morphology, composition as well as crystalline phases of the obtained coatings were analysed by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Finally, the microstructure of the cross section of a coating was investigated via transmission electron microscopy. The observations revealed a great impact of the gas composition on the morphology and crystal structures of the coatings. Within the layer, the growth of columnar microstructures was detected. Additionally, the formation of an amorphous HfN intermediate layer between the substrate and the AlHfN with a thickness of approximately 2 nm was found.

Wear Behaviour of Two Different Cemented Carbide Grades in Turning 316 L Stainless Steel

2018 ◽  
Vol 941 ◽  
pp. 2367-2372 ◽  
Author(s):  
Sara Saketi ◽  
Ulf Bexell ◽  
Jonas Östby ◽  
Mikael Olsson
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Wear Resistance ◽  
Wear Behavior ◽  
Cutting Tools ◽  
Cemented Carbide ◽  
Wear Behaviour ◽  
Binder Phase ◽  
Mechanical Wear ◽  
Cutting Insert

Cemented carbides are the most common cutting tools for machining various grades of steels. In this study, wear behavior of two different cemented carbide grades with roughly the same fraction of binder phase and carbide phase but different grain size, in turning austenitic stainless steel is investigated. Wear tests were carried out against 316L stainless steel at 180 and 250 m/min cutting speeds.The worn surface of cutting tool is characterized using high resolution scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Auger electron spectroscopy (AES) and 3D optical profiler.The wear of cemented carbide in turning stainless steel is controlled by both chemical and mechanical wear. Plastic deformation, grain fracture and chemical wear is observed on flank and rake face of the cutting insert. In the case of fine-grained, the WC grains has higher surface contact with the adhered material which promotes higher chemical reaction and degradation of WC grains, so chemical wear resistance of the composites is larger when WC grains are larger. The hardness of cemented carbide increase linearly by decreasing grain size, therefore mechanical wear resistance of the composites is larger when WC grains are smaller.

Cemented carbide cutting tools coated with silicon nitride

2018 ◽  
pp. 104-109
Author(s):  
V. S. Panov
Keyword(s):  
Silicon Nitride ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Cemented Carbide ◽  
Wear Resistant ◽  
Factors Affecting ◽  
Wear Resistant Coatings ◽  
Cemented Carbide Tool ◽  
Tools Wear ◽  
Coated Cemented Carbide

The paper describes the technology of producing a wear resistant silicon nitride coating on cemented carbide cutting tools and factors affecting its structure and thickness. A review of domestic and foreign authors’ works is given on the properties and applications of cemented carbides in cutting, drilling, die stamping tools, wear resistant materials, for chipless processing of wood, plastics. It is noted that one of the promising ways of cutting tool development is using indexable throwaway inserts (ITI) with wear resistant coatings. The choice of silicon nitride as a material for cemented carbide tool coating is justified. The data on silicon nitride deposition methods, investigation of cutting tool structures and properties are provided. Laboratory and factory tests of Si3N4-coated cemented carbide tools demonstrated coating applicability in improving the wear resistance and lifetime of cutting inserts.

Vibration Polishing Edge Preparation for Cemented Carbide Inserts

2012 ◽  
Vol 201-202 ◽  
pp. 1174-1177
Author(s):  
Jiao Wang ◽  
Hao Wang ◽  
Ai Bing Yu
Keyword(s):  
Cutting Tools ◽  
Abrasive Particle ◽  
Optical Microscope ◽  
Cutting Edge ◽  
Cemented Carbide ◽  
Abrasive Particles ◽  
Cemented Carbide Tool ◽  
Carbide Inserts ◽  
Edge Preparation ◽  
Cemented Carbide Inserts

Micro-cracks on cutting edge will cause early breakages on cutting tools, accelerate tool wear and reduce cemented carbide tool life. Edge preparation can improve the cutting edge quality. Vibration polishing experiments were carried out for cemented carbide inserts edge preparation. Inserts and fixtures were put into the vibration polishing equipment which forced abrasive particles to collide and polish inserts. Edge preparation for fixed type insert and free type insert were compared with three sizes of abrasive particles. And the polishing time was changed for each testing cases. Experiments were carried out by altering polishing time, abrasive particle size and tool clamping way to determine the optimum technology of vibration polishing edge preparation. The experimental results showed that edge breakage numbers of insert significantly reduced. Smooth and round cutting edges were observed by optical microscope after edge preparation. Edge preparation experiments prove that edge preparation can change the cutting edge geometry and improve the cutting tool quality.

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