scholarly journals Perspectives of the industrial recycling of hard-alloy materials waste by electro-erosive grinding

2018 ◽  
Vol 224 ◽  
pp. 01010
Author(s):  
Kharis Rakhimyanov ◽  
Valentina Marusina

The creation of efficient industries is possible by using sustainable technologies based on the processes of recycling of the production waste. First of all, it refers to expensive material waste, including hard alloys. The electro-erosive grinding is considered to be the effective method of recycling such materials. The results of research on recycling the tungsten-cobalt hard alloy show the possibility of obtaining tungsten-carbide powders possessing improved physical and mechanical properties. The technology mentioned is also perspective for recycling tungstenless hard-alloy waste both at the laboratory devices equipped with the RC-generator and at the industrial installations of bulky grinding. It is established experimentally that the electro-erosive grinding of the TN20 tungstenless hard alloy at the laboratory provides obtaining the main volume (up to 85%) of the powder particles of the spherical shape having a dimension of 5 µm and the specific surface of 31.5 m2/g. Higher physical and mechanical properties of powders are also provided during recycling the TN20 alloy waste at the industrial installations of bulky grinding.

Author(s):  
E. V. Petrov ◽  
V. S. Trofimov ◽  
V. O. Kopytskiy

The surface layer of an obstacle made of U8 steel is investigated after high-speed exposure to a flow of powder particles. After analyzing the frames of high-speed photography, the average velocities of movement of particles of tungsten and titanium carbide powders were determined. It is shown that the shock-wave loading of the barrier material and the effect of particles accelerated by the explosion energy provide a change in the physical and mechanical properties of the surface and the volume of the steel barrier material.


2021 ◽  
Vol 23 (1) ◽  
pp. 33-44
Author(s):  
Evgeny Artamonov ◽  
◽  
Andrey Tveryakov ◽  
Anton Shtin ◽  
◽  
...  

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.


2021 ◽  
Vol 325 ◽  
pp. 53-58
Author(s):  
Aleksandr A. Ponomarenko ◽  
Fedor L. Kapustin ◽  
Elena Makarova ◽  
Ekaterina S. Gerasimova

The influence of the chemical composition of bauxite on the mineral formation and structure of sulfoaluminate-ferrite clinker (SAFC), and physical and mechanical properties of cement based on it is studied. Ferrous bauxite, marble crushing screenings and neutralized fluorine-anhydrite were used for the synthesis of SAFC. The compositions of raw mixes of low-and high-alkaline SAFC are calculated with modular characteristics: Mf (ferritic modulus) = 0.35 and 0.7, Мs (sulfate modulus) = 0.167 and 0.5, respectively. Clinker synthesis from a raw mix containing ferrous bauxite with a quality coefficient of 1.7 must be carried out at a temperature of 1250 °C, which is reduced to 1200 °C for burning a raw mix based on bauxite with a quality coefficient of 2.2. Intensive decomposition of anhydrite occurs with the release of sulfur dioxide into the atmosphere at a temperature of 1300 °C, so it is not recommended to burn SAFC at this temperature. The mineral composition of the obtained SAFC is represented by sulfoaluminate, calcium sulfoferrite and free anhydrite. There is no C2S as a separate phase in clinkers, since in the process of their synthesis belite dissolves in 3С(A,F)·СŜ, mainly in the aluminoferrite phase. The use of bauxite with a quality coefficient of 2.2 in the SAFC raw mix increases the cement activity up to 54.2 MPa. Increasing its specific surface from 350 to 460 m2/kg significantly reduces the setting time of cement paste and increases the strength of sulfoaluminate-ferrite cement both in the early (up to 43.4 MPa) and late hardening periods (up to 67.3 MPa).


2016 ◽  
Vol 5 (3) ◽  
pp. 52
Author(s):  
Salokhiddin Nurmurodov ◽  
Alisher Rasulov ◽  
Nodir Turakhodjaev ◽  
Kudratkhon Bakhadirov ◽  
Lazizkhan Yakubov ◽  
...  

<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>


2017 ◽  
Author(s):  
Ahmad Aswad Mahaidin ◽  
Talib Ria Jaafar ◽  
Mohd Asri Selamat ◽  
Salina Budin ◽  
Zaim Syazwan Sulaiman ◽  
...  

2020 ◽  
Vol 299 ◽  
pp. 258-263
Author(s):  
Boris A. Semenikhin ◽  
Lyubov P. Kuznetsova ◽  
Vladimir I. Kozlikin

The results of the research of the use of powders based on tungsten carbide with a particle size of 1 μm or less, obtained by the method of electro-erosion dispersion from the waste of sintered hard alloys, as a dispersed phase of composite galvanic coatings based on iron during the restoration and hardening of car parts are presented. It is shown that the introduction powders of hard alloys of grades VK8 and T15K6 in the chloride electrolyte of iron plating with a concentration of 100 g/l and more, practically does not affect the micro-hardness, but allows to increase the relative wear resistance of the obtained composite galvanic coatings, compared to simple iron galvanic coatings, and, at the same time, increase the life of parts and reduce repair costs.


2012 ◽  
Vol 12 (1) ◽  
pp. 71-74 ◽  
Author(s):  
P. Lichy ◽  
V. Bednarova ◽  
T. Elbel

Casting Routes for Porous Metals Production The last decade has seen growing interest in professional public about applications of porous metallic materials. Porous metals represent a new type of materials with low densities, large specific surface, and novel physical and mechanical properties, characterized by low density and large specific surface. They are very suitable for specific applications due to good combination of physical and mechanical properties such as high specific strength and high energy absorption capability. Since the discovery of metal foams have been developed many methods and techniques of production in liquid, solid and gas phases. Condition for the use of metal foams - advanced materials with unique usability features, are inexpensive ways to manage their production. Mastering of production of metallic foams with defined structure and properties using gravity casting into sand or metallic foundry moulds will contribute to an expansion of the assortment produced in foundries by completely new type of material, which has unique service properties thanks to its structure, and which fulfils the current demanding ecological requirements. The aim of research conducted at the department of metallurgy and foundry of VSB-Technical University Ostrava is to verify the possibilities of production of metallic foams by conventional foundry processes, to study the process conditions and physical and mechanical properties of metal foam produced. Two procedures are used to create porous metal structures: Infiltration of liquid metal into the mold cavity filled with precursors or preforms and two stage investment casting.


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