scholarly journals The structure of composite rollers with iron or nickel-iron base and hard surface layer of WC or TiC based hard alloy produced by the method of hot vacuum pressing with a liquid phase

2020 ◽  
Vol 40 (1) ◽  
pp. 20-29
Author(s):  
Vladislav Kaverinskiy ◽  
Zoya Sukhenko
Keyword(s):  
Surface Layer ◽  
Liquid Phase ◽  
Hard Alloy ◽  
Powder Metallurgy Method ◽  
Hard Alloys ◽  
Nickel Iron ◽  
Base Materials ◽  
Composite Layers ◽  
Iron Nickel ◽  
Liquid Sintering

Abstract In this work the structure and properties of composite rollers with surface layer made of hard alloy were studied. The rollers were made by the powder metallurgy method with sintering during pressing and the presence of a certain liquid phase during sintering (semi-liquid sintering). WC-Co and TiC-Ni-Fe materials were used as hard alloys. Iron-carbon and iron-nickel materials were used as soft base. All of the composite layers were formed in one process. The structure of base materials and border layer of these composites were studied. Investigations of thermocycling sustainability of these composite samples were carried out.

scholarly journals Effects of microsilica content on microstructure and strength of lightweight castable refractories containing porous corundum-spinel aggregate

2009 ◽  
Vol 41 (3) ◽  
pp. 275-281 ◽  
Author(s):  
W. Yan ◽  
N. Li ◽  
B.Q. Han
Keyword(s):  
High Temperature ◽  
Liquid Phase ◽  
Average Pore Size ◽  
Mercury Porosimetry ◽  
High Strength ◽  
Apparent Porosity ◽  
Liquid Content ◽  
Average Pore ◽  
Crushing Strength ◽  
Liquid Sintering

High-strength, lightweight castable refractories based on spinel were prepared by introducing porous corundum-spinel aggregate and appropriate microsilica. The effects of microsilica content on microstructure and properties of lightweight castable refractories were investigated using SEM, XRD, mercury porosimetry measurements and FactSage thermochemical software. It's found that microsilica was almost dissolved into a liquid phase at high temperature, which promoted liquid sintering. With increasing microsilica content, the matrices became denser and average pore size of matrices increased, then apparent porosity decreased, crushing strength increased and content of liquid phase in castables at 1600?C increased. The appropriate microsilica content is 0.65 to 1.95 wt%, which reaches to a compromise among apparent porosity (33-38%), crushing strength (82-125MPa) and liquid content (1.80~4.97 wt%).

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.

Surface modification of die steels with B—Al-layers by thermal-chemical treatment

2021 ◽  
pp. 557-564
Author(s):  
N.S. Ulakhanov ◽  
U.L. Mishigdorzhiyn ◽  
A.G. Tikhonov ◽  
A.I. Shustov ◽  
A.S. Pyatykh
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Surface Layer ◽  
Surface Modification ◽  
High Temperature ◽  
Chemical Treatment ◽  
Quality Parameters ◽  
Processing Temperature ◽  
Die Steels ◽  
Composite Layers

The effect of diffusion high-temperature boroaluminizing (HBA) on the mechanical properties and quality parameters of the surface layer of stamp steels 5KhNM and 3Kh2V8F is shown. An analysis of the microstructure and composition of diffusion composite layers obtained as a result of thermal-chemical treatment (TCT) is presented and the distribution of microhardness in these layers is studied depending on the formed borides and carbides. The influence of processing temperature modes of on the parameters of roughness was experimentally established and the wear resistance characteristics of the processed surfaces of the investigated materials were determined.

scholarly journals A magnetic study of the iron-nickel-aluminium system

1939 ◽  
Vol 171 (947) ◽  
pp. 525-540 ◽  
Keyword(s):  
Magnetic Properties ◽  
X Ray ◽  
Nickel Iron ◽  
Fundamental Properties ◽  
Saturation Intensity ◽  
Structure Changes ◽  
Iron Nickel ◽  
The Subject ◽  
High Fields ◽  
Ferromagnetic Magnetization

The iron-nickel-aluminium ternary system has been brought into prominence in recent years on account of its application in the permanent magnet industry. A study of some magnetic properties of this system has been made by Köster (1932-3), but his work is largely concerned with features other than those dealt with by the writer. An exhaustive X-ray examination of these alloys has been carried out by Bradley and Taylor (1938), and the information obtained has been used to throw light on the permanent magnetism in this system (Bradley and Taylor 1937 a, b, c ). Through the collaboration of Dr Bradley the writer has been able to make magnetic investigations on the same specimens as were used in the X-ray analysis, and the present account deals with a survey of the variation of the saturation intensity of these alloys with temperature. Owing to the complexity of the magnetic properties of alloys in this system, it is essential that the more fundamental properties should be the subject of the first investigation. The properties of ferromagnetic materials in low magnetizing fields depend to a considerable extent upon heat treatment, whilst on the other hand the saturation intensity in high fields shows less variation, and is in some degree a measure of the number of elementary magnets, presumably electron spins, contributing to the ferromagnetic magnetization of the particular alloy. Furthermore, the variation of the saturation intensity with temperature should give indications of any structure changes which may occur. A new method for the rapid measurement of saturation intensities for a few milligrams of substance over a range of temperature has been evolved (Sucksmith 1939) and the method there described has been used in the investigation on the nickel-iron-aluminium system.

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.

Investigation on the Bonding Strength between the Hard Alloy Cladding Layer and the Steel Substrate

2004 ◽  
Vol 471-472 ◽  
pp. 136-139
Author(s):  
Fu Tian Liu ◽  
S.X. Song ◽  
Jun Ru Yang ◽  
Wei Ling Huang ◽  
Zhao Qian Li
Keyword(s):  
Liquid Phase ◽  
Hard Alloy ◽  
Bonding Strength ◽  
Steel Substrate ◽  
Liquid Phase Sintering ◽  
Steel Plates ◽  
Tensile Fracture ◽  
Cladding Layer ◽  
Ternary Boride ◽  
Cladding Material

By virtue of the technology characteristics of liquid-phase sintering ternary boride hard alloy cladding material, two steel plates were bonded together by a ternary boride hard alloy cladding material through a liquid phase sintering procedure. The bonding strength between a hard alloy cladding layer and a steel substrate was characterized by means of measuring the bonding strength of two steel plates bonded by the hard alloy cladding layer. The bonding strength between hard alloy cladding layer and the steel substrate was measured by transverse rupture strength method, tensile fracture method and single side shear method, respectively. The results show that a firm metallurgical bonding is formed during the liquid phase sintering.

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