Papers by Keyword: Tungsten Carbide

Abstract: This study presents the development of an advanced 215.9 mm drill bit with an optimized material distribution to enhance wear resistance, durability, and operational efficiency in highly abrasive formations. A comprehensive scanning electron microscopy (SEM) analysis of the powders used in the drill bit's construction was conducted using the TESCAN Mira 3 LMU system. The analysis included tungsten carbide–cobalt (WC–Co) and diamond-containing composite powders. The results revealed that WC–Co powders exhibit high density and uniform particle distribution, making them suitable for load-bearing components, while diamond-containing powders ensure superior cutting performance and wear resistance. Based on these findings, a rational material allocation was implemented: WC–Co-based materials were used for structural elements, and diamond-containing powders were applied in cutting and undercutting inserts. Process was optimized to prevent thermal degradation of the polycrystalline diamond compact (PDC) inserts. The developed drill bit was designed for rotary drilling with an axial load range of 20–80 kN, rotation speeds of 80–250 rpm, and a drilling fluid flow rate of up to 40 L/s. The proposed design is particularly suited for the geological and technical conditions of Kazakhstan’s oil and gas fields, contributing to reduced drilling costs and increased efficiency.

Abstract: Electrochemical research is devoted to the development of a method of processing secondary raw materials containing tungsten in the form of a pseudoalloy of the carbide type WC–Co in sulfate solutions. The target processing products are: powders of tungsten oxides of lower oxidation states, which can be reduced to metallic tungsten with lower costs. Using the methods of linear and cyclic voltammetry, it was established that the selective dissolution of the cobalt component of the pseudoalloy in the studied solutions occurs at potentials more positive than 0.2 V, carbon is removed from the working electrode at a potential > 0.8 V. At the same time, tungsten is oxidized to the higher oxide WO₃. It was determined that in sulfuric acid, with an increase in its concentration from 1 to 5 mol∙dm-3, the current density decreases, which is associated with the formation of a solid surface layer of tungsten oxide on the surface of the anode, which passivates the surface. It was established experimentally that when adding 1 mol∙dm^-3 of H₂SO₄ hexamine (C₆H₁₂N₄) with a concentration of 0.9 mol∙dm^-3 to a solution, it is possible to block the process of formation of a passivating film and obtain powders of tungsten oxides of lower oxidation states.

Abstract: Polyamide 66 (PA 66) or Nylon 66 is a strong, easily processed polymer with high thermal resistance and excellent mechanical properties. Tungsten carbide (WC/Co-Cr 86/10-4), known for its exceptional hardness and elasticity, is commonly used for coatings in the thermal spraying and coating industry. In this study, we examined the microstructural, mechanical, and thermal properties of composites made from waste micro and nano WC/Co-Cr 86/10-4 powder and a PA66 matrix. PA66 was reinforced with varying ratios of 3, 6, and 10 wt.% WC/Co-Cr 86/10-4. The composite specimens were created by mechanically mixing granular PA66 and micro and nano WC/Co-Cr 86/10-4 powders and molding them under controlled temperature. Mechanical properties were evaluated through ductility and hardness tests, while thermal properties were determined through DSC analysis. The SEM observation revealed the distribution of WC/Co-Cr 86/10-4 within the polymer matrix. The DSC analysis indicated that the composite had a slightly higher melting temperature than pure PA66, and the thermal conductivity also increased slightly. The experimental results demonstrated that the mechanical properties of the composite improved as the WC/Co-Cr 86/10-4 content increased, specifically in terms of tensile strength and hardness. Additionally, the composite exhibited enhanced interfacial adhesion, mechanical behavior, and thermal properties. This composite, utilizing WC/Co-Cr 86/10-4 waste and recycled PA66, allows for the repurposing of industrial waste.

Abstract: A new method for obtaining submicron hard alloys based on sintered tungsten carbide with cobalt by joint low-temperature carbothermic synthesis in vacuum has been developed. The compositions of the initial components for the synthesis of powders of the composition WC-6%Co and WC-10%Co are calculated. The main component for the synthesis of submicron tungsten carbide powders is tungsten oxide WO_2.9, obtained by reducing α-tungsten oxide WO₃ in a hydrogen medium at a temperature of 500-550 °C. The powders obtained by synthesis are characterized by high hardness values (up to 94 HRA). Cutting tests of replaceable polyhedral plates made from the obtained powders for processing a heat-resistant alloy have shown satisfactory results. The microstructure of the alloys was analyzed using scanning electron microscopy.

Abstract: In the current paper, the effect of two different coating techniques of boronizing and tungsten carbide (WC) coating on the room and high temperature tensile behavior of the AISI 321 stainless steel were investigated. Consequently, the fracture morphology observations were conducted via scanning electron microscopy (SEM) to inspect the variation of fracture mechanisms after implementing different coating methods. The results of tensile tests at room temperature revealed that despite boronizing reduced the yield strength of the sample due to the softening and grain growth at high coating temperature, the dispersion of boron particles improved the work hardening and ductility of boronized AISI 321. In contrast, the strain to failure of the WC coated sample was decreased due to the fast fracture of the ceramic WC layer at both room and high tensile tests. Furthermore, results of SEM revealed that particle decomposition occured on the fracture surface of the boronized 321 stainless steel represented by dispersed boron particles on the edges of the dimples after failure at high temperature.

Abstract: Electrochemical research is focused on the tungsten extraction during acid electrochemical treatment of WC-Co pseudoalloy in chloride solutions. The target resulted products of the treatment are: tungsten oxide (VI), tungsten powder with a given particle size distribution (2…3 μm). Based on the analysis of kinetics, the mechanism of dissolution of the WC-Co pseudoalloy in a solution of 2.5 mol∙dm-3 HCl and with the addition of HF was proposed. It was found that a well-soluble higher tungsten chloride is formed on the surface of the pseudoalloy, which is eventually hydrolyzed in aqueous solution to form tungsten oxides. The dispersion control levers were investigated and the technological parameters of obtaining tungsten metal powder from low-temperature ionic alloys (NaCl-KCl-CsBr-NaF) were determined, which make it possible to obtain tungsten metal powder of a given particle size distribution. It is stated that the use of tungsten powder (W or WO3) for the modification of aramid fiber can significantly increase the heat resistance of aramid fabric and reduce its wear

Abstract: The paper presents the results of research of influence of nanopowders of tungsten compounds obtained from hard-alloy waste on structure formation and kinetics of cement stone strength gain. The positive effect of additives on the mechanical and structural characteristics of the cement stone in the concentration range of 1...5 wt.% has been established.

Abstract: The technology of friction-electric modification of the surfaces of machine parts with W₂C and WC tungsten carbides is considered. A method of modifying the surface layer by implantation of materials based on tungsten carbides is investigated in order to increase the wear resistance of parts forming tribo-conjugations in heavily loaded units of multi-purpose tracked and wheeled vehicles.

Abstract: The paper presents the results of tests of carbon plastic samples consisting of carbon fabric Grafill TR30S-S (Italy) and epoxy resin binder EPR 320 modified by WC tungsten carbide nanopowders in the form of agglomerates. The positive effect of additives on the tensile strength and on the modulus of elasticity at transverse bending of the concentration of additives 1-3% is shown.

Abstract: This article discusses the issue of increasing the efficiency of alloying low-carbon steel during electroslag remelting with fluxes obtained on the basis of multicomponent mineral raw materials. The process of transition of an alloying element, from molten slag to metal, was investigated in various operating modes of the slag system, where the system itself experienced various degrees of hydrodynamic impact. A model is proposed and described, showing the uneven distribution of the alloying element in the metal melt. The composition and structure of the obtained alloys are investigated.