scholarly journals TECHNOLOGY OF DEPOSITION OF COATINGS FROM HARD ALLOYS ON THE WORKING SURFACES OF FRICTION UNITS

2021 ◽  
pp. 55-60
Author(s):  
A. V. Krokhalev ◽  
V. O. Kharlamov ◽  
D. R. Chernikov ◽  
A. S. Balagurov ◽  
S. V. Kuz’min ◽  
...  
Keyword(s):  
Hard Alloy ◽  
Centrifugal Pump ◽  
High Hardness ◽  
Hard Alloys ◽  
Friction Characteristics ◽  
Friction Units ◽  
Siliconized Graphite

A technology has been developed for applying explosively to the surface of centrifugal pump parts for pumping overheated distillate under NPP conditions of hard alloy coatings of the CrC-Ti system, which ensures high hardness of the coatings and the strength of their connection with the surface to be coated, and the best tribotechnical materials in comparison with existing materials friction characteristics against siliconized graphite in water.

The Effect Covering on the Change in the Properties of Hard Alloys

2021 ◽  
Vol 887 ◽  
pp. 376-382
Author(s):  
S.I. Bogodukhov ◽  
E.S. Kozik ◽  
E.V Svidenko ◽  
V.S. Garipov
Keyword(s):  
Hard Alloy ◽  
High Speed ◽  
Manufacturing Industry ◽  
Bending Strength ◽  
High Speed Steel ◽  
Physical And Mechanical Properties ◽  
High Hardness ◽  
High Heat ◽  
Hard Alloys ◽  
Operational Parameters

Currently, hard alloys are common tool materials; they are widely used in the tool manufacturing industry. Due to the presence of refractory carbides in its structure, hard-alloy tools feature a high hardness of 80 to 92 HRA (73 to 76 HRC); a high heat resistance (from 800 °С to 1,000 °С); therefore, they can be used at speeds that are several times higher than cutting speeds of high-speed steel grades. Hard alloys are used in the form of plates that are either mechanically fixed on or soldered to tool holders. The main operational parameters, that determine the hard-alloy tool operation mode, are hardness, wear resistance, and bending strength. The operational parameters of alloy are highly dependent on its structure, phase composition, lattice block sizes, and micro-stress values [1-20]. The main methods to enhance physical and mechanical properties of hard-alloy plates are improvement of manufacturing technology, including production of fine-grained alloys and microalloying, as well as applying composite coating by vacuum deposition, which allows to increase the tool resistance 1.5 to 2 times.

Tribotechnical characteristics of hard alloys in sliding friction units

2020 ◽  
pp. 87-97
Author(s):  
K. D. Khromushkin ◽  
B. G. Ushakov ◽  
A. V. Kochergin ◽  
R. A. Suleev ◽  
O. N. Parmenova
Keyword(s):  
Experimental Data ◽  
Sliding Friction ◽  
Heating Temperature ◽  
Hard Alloys ◽  
Friction Units ◽  
Wear And Friction ◽  
Friction Path ◽  
Friction Parameters ◽  
Tribotechnical Characteristics ◽  
Temperature Surface

The paper presents experimental data on the study of the friction parameters of hard alloys in sliding friction units, including the heating temperature, surface roughness, wear and friction coefficient, depending on the duration of the test and the friction path.

scholarly journals X-RAY SPECTRAL MICROANALYSIS OF ELECTROEROSIVE POWDER MATERIAL OBTAINED IN AN ETHYL ALCOHOL MEDIUM FROM WASTE OF A NON-TUNGSTEN HARD ALLOY OF THE KNT16 BRAND

2020 ◽  
pp. 33-36
Author(s):  
E. V. Ageeva ◽  
B. N. Sabel’nikov
Keyword(s):  
Hard Alloy ◽  
Powder Material ◽  
Ethyl Alcohol ◽  
Scientific Research ◽  
Powder Materials ◽  
Hard Alloys ◽  
Processing Waste ◽  
Resource Saving ◽  
X Ray ◽  
Alcohol Medium

The first appearance of tungsten-free hard alloys (TFHA) was noted in the early 30s of the last century, but they did not receive due attention and, accordingly, spread due to insufficient strength and were replaced by tungsten-containing alloys of such groups as VK, TC and TTK. However, the rapidly developing shortage of expensive tungsten pushed in the late 50s to return to the search for hard alloys, the composition of which does not include tungsten. Due to the growing demand for tungsten-free hard alloys, the problem of recycling their waste with the possibility of reuse is acute in the industry. The purpose of this work was to conduct x-ray spectral microanalysis (RSMA) of powder material (PM) obtained by electroerosive dispersion (EED) in ethyl alcohol from waste of a non-tungsten hard alloy of the KNT16 brand. The resulting powder material was examined using an energy-dispersion x-ray analyzer from EDAX, built into a scanning electron microscope "QUANTA 600 FEG". In the course of scientific research, the spectra of characteristic x-ray radiation on the surface of the experimentally obtained sample were obtained. The results obtained in the course of scientific research can be used to create environmentally friendly resource-saving processes for processing waste of tungsten-free hard alloys into powder materials.

Influence of thermal cycling modes on VK8 hard alloy mechanical and tribological properties

2020 ◽  
pp. 55-65
Author(s):  
S. I. Bogodukhov ◽  
E. S. Kozik ◽  
E. V. Svidenko
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Wear Resistance ◽  
Thermal Cycling ◽  
Hard Alloy ◽  
Tribological Properties ◽  
High Speed ◽  
Metal Cutting ◽  
Hard Alloys ◽  
Mechanical And Tribological Properties

Hard alloys are popular materials widely used in the toolmaking industry. Refractory carbides included in their composition make carbide tools very hard (80 to 92 HRA) and heat-resistant (800 to 1000 °С) so as they can be used at cutting speeds several times higher than those used for high-speed steels. However, hard alloys differ from the latter by lower strength (1000 to 1500 MPa) and the absence of impact strength, and this constitutes an urgent problem. We studied the influence of thermal cycling modes on the mechanical and tribological properties of VK8 (WC–8Co) hard alloy used in the manufacture of cutters and cutting inserts for metal working on metal-cutting machines. As the object of study, we selected 5×5×35 mm billets made of VK8 (WC–8Co) alloy manufactured by powder metallurgy methods at Dimitrovgrad Tool Plant. The following criteria were selected for heat treatment mode evaluation: Vickers hardness, flexural strength, and mass wear resistance (as compared to the wear of asreceived samples that were not heat treated). Plates in the initial state and after heat treatment were subjected to abrasion tests. Wear results were evaluated by the change in the mass of plates. Regularities of the influence of various time and temperature conditions of heat treatment on the tribological properties of products made of VK group tungsten hard alloys were determined. An increase in the number of thermal cycling cycles improved such mechanical properties of the VK8 hard alloy as strength and hardness. When repeating the cycles five times, an increase in abrasive wear resistance was obtained compared to the initial nonheat-treated sample. The elemental composition of the VK8 hard alloy changed insignificantly after thermal cycling, only a slight increase in oxygen was observed on the surface of plates. The grain size after thermal cycling increased in comparison with the initial VK8 hard alloy. It was found that VK8 hard alloy thermocyclic treatment leads to a change in the phase composition. X-ray phase analysis showed the presence of a large amount of α-Co with an hcp-type lattice on the surface of a hard alloy and a solid solution of WC in α-Co. A change in the cobalt modification ratio causes a decrease in microstresses. An analysis of the carbide phase structure state showed that the size of crystallites and microstresses changed after thermal cycling. The lattice constant of the cobalt cubic solid solution decreased, which may indicate a decrease in the amount of tungsten carbide and carbon dissolved in it. Statistical processing of experimental results included the calculation of the average value of the mechanical property, its dispersion and standard deviation in the selected confidence interval.

Diffusion Saturation by Titanium from Liquid-Metal Media as Way to Increase Carbide-Tipped Tool Life

2017 ◽  
Vol 265 ◽  
pp. 181-186 ◽  
Author(s):  
A.G. Sokolov ◽  
E.E. Bobylyov
Keyword(s):  
Liquid Metal ◽  
Hard Alloy ◽  
Hard Alloys ◽  
Functional Coatings ◽  
High Quality ◽  
Diffusion Coatings ◽  
Coating Composition ◽  
The Media ◽  
Diffusion Metallization ◽  
Titanium Diffusion

The analysis of the strengths and weaknesses of the existing technologies aimed at improving the performance properties of carbide-tipped tools is presented. The results of studies into the process of diffusion metallization by titanium of a carbide-tipped tool TK type from the media of fusible liquid-metal solutions is given. The influence of titanium diffusion coatings on the durability of carbide tools is investigated. A method of providing formation on hard alloys for wear-resistant titanium high-quality functional coatings is described. The thickness of the coating varies depending on the temperature and exposure time, and ranges from 4 to 6 μm. The hardness of the coatings obtained depends on the temperature of the coating and modes of pre-carburizing, and varies from 24100 to 30000 MPa. The microstructure of the coatings is investigated. The coating consists of two layers: the coating and the transition zone, the size and hardness of which depends on the conditions of pre-carburization and modes of application of the coating. The dependence of the coatings thickness on the duration of the plates exposure in the melt, the temperature of coating composition from the coated hard alloy is investigated.

scholarly journals THERMODYNAMIC MODEL OF AERODYNAMIC SOUND HARDENING METHOD

2020 ◽  
Vol 4 (53) ◽  
pp. 65-69
Author(s):  
Anatoliy N. JIGALOV ◽  
◽  
Valeriy K. SHELEG ◽  
Dmitriy D. BOGDAN ◽  
◽  
...  
Keyword(s):  
Impact Toughness ◽  
Hard Alloy ◽  
Thermodynamic Model ◽  
Thermodynamic System ◽  
Initial Structure ◽  
Hard Alloys ◽  
Resonant Amplitude ◽  
Aerodynamic Sound ◽  
Wave Effects ◽  
The Impact

As a result of scientific research, a method of aerodynamic sound hardening (ADH) has been developed and patented, which makes it possible to achieve improved properties of hard alloys by reducing their defectiveness, improving the homogeneity of the structure. The physics of the ADH process is that the hardened product is preheated to an acceptable temperature at which the hard alloy does not lose the plasticity and hardness acquired during manufacture. Then the product is exposed to sound frequency waves, reduced in the range of 140...160 Hz into a resonant state, in which the formation of a resonant amplitude increased by several hundred times occurs. The article gives a description of the essence of the created ADH method. The dependence for determining the action energy on a hardened solid by ADH is provided. A thermodynamic model of the ADH method is presented, based on energy thermal and wave effects on the hardened structure. On the basis of the thermodynamic explanation, the ADH method is reduced to a change in the initial structure of the hard alloy under the influence of temperature and wave resonant energy fluxes on it, through which activating and dissipative processes of energy outflow are excited in the hardening object in the mode of an open thermodynamic system. In addition, the quasi-static process of wave energy transfer, carried out in a non-equilibrium medium, significantly exceeds the relaxation time of the strengthening system. When hardening by ADH, the impact toughness increases by 19–23 % in hard alloys, while the values of impact toughness equal to 39.54–42.05 kJ/m2 are achieved, the hardness according to the HRC parameter increases by 3.0–5.2 %.

scholarly journals Determination of maximum working capacity of retrofittable cutters on the basis of physical-mechanical features of tool hard alloys

2018 ◽  
Vol 224 ◽  
pp. 01046 ◽  
Author(s):  
Evgeniy V. Artamonov ◽  
Andrey M. Tveryakov ◽  
Anton S. Shtin
Keyword(s):  
Hard Alloy ◽  
Russian Federation ◽  
Hard Alloys ◽  
Working Capacity ◽  
Processing Efficiency ◽  
Made In

This research is dedicated to the determination of maximum working capacity temperature of tool hard alloy cutters during a processing of parts by means of cutting made of hard-to-cut materials including assessment of possibility of using of tools made in Russian Federation without loss of the processing efficiency.

Determination of temperature of maximum operability of replaceable cutting hard-alloy inserts based on study of electromagnetic properties change

2021 ◽  
Vol 23 (1) ◽  
pp. 33-44
Author(s):  
Evgeny Artamonov ◽  
◽  
Andrey Tveryakov ◽  
Anton Shtin ◽  
◽  
...  
Keyword(s):  
Hard Alloy ◽  
Eddy Currents ◽  
Physical And Mechanical Properties ◽  
Electromagnetic Properties ◽  
Hard Alloys ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Cutting Inserts ◽  
Non Destructive

Introduction. Today, under the conditions of sanctions, the Russian Federation, more than ever before, needs the development of energy-saving technologies in various industries. There is no secret that when assigning cutting modes for new materials, tool companies conduct tests for the destruction of replaceable cutting inserts during cutting, the obtained numerical values are published in catalogs. The greatest impact on the life and operability of hard alloy cutting tools is exerted by the physical and mechanical properties of tool materials. Studies have shown that the physical and mechanical properties of tungsten hard alloys in the process of operation, namely in the process of cutting difficult-to-process materials under the influence of high temperatures, vary symmetrically. During the development of the laboratory plant, a literary review was carried out, which showed that at the moment non-destructive testing methods of technological facilities are widely used. Methods of non-destructive testing of technological objects allow conducting studies of the state of material, defects in the structure, internal changes, without samples destroying; this advantage was decisive during the literary review. The object of this study is replaceable cutting hard alloy inserts made of single carbide hard alloy В35 (92%WC+8%Co), tetrahedral in the state of supply. The subject of the study is the relationship between the changes of the magnetic component of the properties of a single-carbide hard alloy В35 (92%WC+8%Co) depending on the effect of high temperatures on it. This study is based on the laws of physics of the division of electrodynamics, as well as well-known non-destructive testing techniques, scientific foundations of material science. All studies are carried out in accredited laboratories of Tyumen Industrial University. The reliability of the obtained data is confirmed by the high correlation of the results of numerical values with the data obtained by the scientific predecessors. Research methodology. The paper shows the developed plant for determination of the maximum operability temperature of replaceable cutting hard-alloy inserts on the basis of study of change of electromagnetic properties. The method of research is given. Tests of the specimen are carried out during heating of replaceable cutting inserts made of tungsten hard alloy B35 (92%WC+8%Co). The heating temperature interval is selected in accordance with the temperature mode of the cutting process in the blade treatment of hard-to-process materials. Thus, heating is carried out in the range from 0 to 1000˚ C. The heating itself is carried out by the flame method manually. Results and discussions. Based on the results of experimental studies, tables of the results are compiled, where, with an interval of 10 °C, the corresponding values of the magnetic field of eddy currents induced in replaceable cutting inserts made of tungsten hard alloy B35 (92 %WC+8 %Co) are indicated. The results of the investigation are obtained to determine the maximum operability temperature of replaceable cutting hard alloy inserts based on the study of the change in electromagnetic properties for the hard alloy B35 (92%WC+8%Co) amounted to 460…730 °C, which corresponds to a cutting speed of 18 m/min during the treatment of the alloy EI867-VD (57 %Ni9 %Mo10 %Cr6 %W4.2 %Al4 %Co). On the basis of persistent tests in factory conditions, it is proved that the developed technique allows determining temperature intervals of maximum operability based on the study of changes in electromagnetic properties (magnetic field of eddy currents arising in replaceable cutting inserts) of hard alloys. These intervals make it possible to assign the most appropriate operating conditions for the cutting tool based on a scientifically sound technique that allows using the maximum tool resource.

scholarly journals Development of New Structural Materials with Improved Mechanical Properties and High Quality of Structures through New Methods

2016 ◽  
Vol 5 (3) ◽  
pp. 52
Author(s):  
Salokhiddin Nurmurodov ◽  
Alisher Rasulov ◽  
Nodir Turakhodjaev ◽  
Kudratkhon Bakhadirov ◽  
Lazizkhan Yakubov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Physical And Mechanical Properties ◽  
High Hardness ◽  
Structural Materials ◽  
Practical Implementation ◽  
Hard Alloys ◽  
Plasma Chemical ◽  
Hard Materials ◽  
Initial Stage

<p class="1Body">Up-to-date science and technology requires further development and wide introduction of new high- performance processes to produce refractory metals. These may include plasma chemical technology of high dispersed powders production. Practical implementation of plasma chemical method in producing and processing of high dispersed powders is in its initial stage. Along with this at the present time the demand for processing of structural materials with improved physical and mechanical properties is now steadily increasing. Such materials have low machinability due to high hardness and durability at high temperatures which results in heavy wear of a cutting tool. To improve the efficiency when processing hard-to-cut materials it is necessary to enhance the tool’s durability; this can be provided by application of new grades of hard alloys received from tungsten nanopowders. New alloy, obtained by the new developed technology, has higher degree of hardness and wear resistance compared with existing alloys and will be intended for hard materials processing.</p>

scholarly journals MICROANALYSIS OF ELECTROSPARK COATINGS BASED ON ELECTROEROSION POWDERS

2017 ◽  
Vol 21 (3) ◽  
pp. 34-40
Author(s):  
E. V. Ageeva ◽  
A. Yu. Altukhov ◽  
E. P. Novikov
Keyword(s):  
Hard Alloy ◽  
High Speed ◽  
Electrode Materials ◽  
High Speed Steel ◽  
Steel Powder ◽  
Optical Microscope ◽  
Hard Alloys ◽  
Functional Coatings ◽  
Electrospark Coating ◽  
Electroerosion Dispersion

The development of modern engineering requires improvement of quality, reliability and durability of parts, assemblies and mechanisms. One of the efficient ways to solve these problems is to applyf functional coatings obtained by the method of electric-spark alloying (ESA). Main electrode materials are mostly sintered hard alloys, which cost due to expensive tungsten in them is relatively high. To solve this problem, a VK8 (90%) hard alloy powder (as a main part) and 10% of high speed steel powder, Gr. R6M5 are proposed to be used as an electrode material. One of the promising methods to produce powders from almost any conductive material, including hard alloy and high speed steel wastes, is the method of electroerosion dispersion (EED), characterized by relatively low energy costs and an environmentally friendly process. The aim of this work is to perform a microanalysis of a steel 30KHGSA section substrate and electrospark coating obtained by electrospark alloying by UR-121 using electrodes of a mixture of electroerosion powders VK8 (90%)+R6M5 (10%), obtained by electroerosion dispersion of hard alloy and high speed steel wastes in illuminating kerosene. To obtain a micro and nano powder of hard alloy and high speed steel wastes a unit for electric erosion dispersing of conductive materials was used. Microanalysis was performed by means of an inverted optical microscope OLYMPUS GX51. The microanalysis allowed us to determine the shape and size of individual grains and their relative positions to identify the presence of inclusions and microdefects and to judge on the properties of the substrate (30KHGSA) and the coating (VK8+R6M5).

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