News & Events

Study on Leaching of Cobalt and Tungsten Carbide in Cemented Carbide Tool

ABSTRACT During the high speed cutting of cemented carbide tool, water-based metal working fluid must be used, which results in the leaching of cobalt and tungsten carbide in cemented carbide. Through immersion test, the effects of triethanolamine solution, sodium carbonate solution and 1H-benzotriazole solution on the leaching of cobalt and tungsten carbide in cemented carbide tool at different temperatures were sdudied by means of scanning electron microscope and en-ergy spectrum analysis. The results show that triethanolamine solution has effect on the leaching of cobalt in cemented car-bide, the leaching is more obvious with increasing temperature, the cobalt leaching rate is 47.72% at 150 ℃ compared with that of 17.32% under normal temperature; sodium carbonate solution has effect on the leaching of tungsten carbide in cemented carbide tool, the leaching is more obvious with increasing temperature, the tungsten leaching rate is 45.59% at 150 ℃ compared with that of 13.28% under normal temperature; 1H-benzotriazole solution has no effect on the leaching of cobalt in cemented carbide, the leaching effect is not obvious for tungsten in cemented carbide, the tungsten leaching rate is only 1.28% at 150 ℃.

KEY WORDS cemented carbide; triethanolamine; sodium carbonate; 1H-benzotriazole; cobalt; tungsten carbide

Water-based cutting fluid used in the base oil mostly refined mineral oil. Refined mineral oil has a long history, mature technology, low prices, but its biodegradability can only reach 40% [1]. The use of a large amount of mineral oil has had a bad effect on the environment. With the rapid development of modern machinery manufacturing and green manufacturing requirements, the performance of water-based processing fluid put forward higher requirements. Not only to protect the tool, but also to be environmentally friendly. And thus now reduce the water-based cutting fluid in the use of base oil, looking for use and environmental health of the material to replace, but also the development of new environmentally friendly additives.

When the tool is cut at high speed, the tool will rub with the workpiece, chip and so on. The strong friction causes the temperature of the contact area to rise and there is a huge pressure. Under such conditions, the tool will react chemically and aggravate the wear of the tool , So that the life of the tool to reduce. In order to extend the service life of the tool to ensure the quality of the workpiece, the tool in the high-speed machining process will use water-based processing fluid. Under the action of the processing fluid, the cutting zone temperature decreases, reducing friction, thereby reducing the wear of the tool. However, the use of water-based processing fluids can cause cobalt (Co) and tungsten carbide (WC) leaching in cemented carbide tools to exacerbate tool wear and affect tool usage. Processing fluid in the Co, WC content will gradually increase, damage the health of workers, but also cause environmental pollution. Therefore, many people have begun to pay attention to the processing fluid on the carbide cutting tools in the Co, WC leaching phenomenon and hazards.

In order to reduce Co and WC leaching in carbide cutting tools and to protect human health, it is necessary to study the effect of the composition of water-based working fluid on the leaching of cobalt and tungsten in cemented carbide tools, and analyze the leaching mechanism. Qualitative alloy tool in the Co, WC leaching effective to provide the basis for the inhibitor.

1 test section

1.1 Experimental apparatus, reagents and samples: Instrument: S-4800 field emission scanning electron microscopy and energy spectrometer; hydrothermal synthesis reactor; constant temperature drying box; electronic analytical balance (accuracy of 0.0001). Hydrothermal synthesis reactor, also known as (high pressure digestion tank, pressure soldering) is a certain temperature, a certain pressure conditions to provide chemical synthesis of the reactor. It is made of high quality stainless steel. The interior has polytetrafluoroethylene, stainless steel and so on. Hydrothermal synthesis reactor main technical indicators: 1) operating temperature: ≤ 260 ℃; 2) working pressure: ≤ 4 MPa; 3) heating, cooling rate: ≤ 5 ℃ / min.

The working environment of the cutting tool is simulated, that is, the pressure and temperature are in the cutting area. The use of hydrothermal synthesis reactor, to the experiment to provide a certain pressure and temperature, which is similar to the simulation of a certain tool temperature processing pressure occurred in the chemical wear test. Reagents: the use of water-based processing fluid often added to the anti-rust additives triethanolamine, sodium carbonate, benzotriazole as an experimental reagent.

Sample: YG8 Carbide blade. 1.2 Immersion Carbide Blade Experiments

In the carbide cutting tool production and cutting process, a large number of processing fluid constantly pouring on the tool. Simulation of the use of the tool environment, according to the working temperature of the reactor and the actual working temperature can be set to the experimental temperature of 150 ℃. Taking into account the use of cutting fluid additive percentage of the selected solution concentration of 1%.

At a temperature of 150 ° C and a temperature of 150 ° C, the tool was immersed in a 1% solution of triethanolamine, 1% solution of sodium carbonate and 1% solution of benzotriazole, respectively, for 48 h, and then sawed with a S-4800 field emission scanning electron microscope Analysis of the mass fraction of cobalt and tungsten before and after immersion in cemented carbide tool surface by energy spectrum analyzer. The leaching degree of Co and WC elements in the experimental solution was characterized by the leaching rate of the element, that is, the loss rate of the cobalt and tungsten mass fraction on the surface of the cemented carbide tool before and after immersion.

2 Experimental results and discussion: 2.1 Triethanolamine solution immersion carbide tool experimental results and analysis At room temperature and 150 ℃ when the carbide cutting tools in triethanolamine solution before and after soaking energy spectrum analysis results shown in Table 1, Table 2. The results show that the leaching rate of cobalt in the cemented carbide tool is 17.32%, and the leaching of cobalt is more obvious when the temperature is higher. When the temperature is 150 ℃, the cobalt The leaching rate was 47.72%. While the triethanolamine solution had no effect on the leaching of tungsten.

The degree of concavity and convexity of the surface of the cemented carbide was better than that of the original blade, which indicated that the triethanolamine had leaching effect on the cemented carbide tool. Triethanolamine is a good performance of multi-functional water-based processing fluid, commonly used as water-soluble anti-rust agent, emulsion stabilizer, pH adjustment agent and surfactant. Triethanolamine molecules contain a nitrogen atom and three oxygen atoms, nitrogen, oxygen atoms are contained in the solitary electrons, so triethanolamine is a good ligand. In the coordination compound, the ligand must have a solitary electron that can be given; and the central ion (or atom) of the forming body must have an empty valence orbit to accept the lone pair electrons given by the ligand [2 ]. The outer electrons of Co2 + are 3d74s4p4d, and a d electron in the 3d orbit can be excited to a 4d orbit with higher energy level, so that the outer electron becomes 3d64s4p4d1, so that Co2 + has 6 empty orbits, according to molecular orbital Theory, Co2 + can be coordinated with the ligand to form complexes [3]. Triethanolamine can make cobalt leaching is due to triethanolamine can form complex with cobalt, this complex into the solution, resulting in cobalt carbide leaching, the temperature increases, so that the electrochemical reaction of the metal to promote the promotion of triethanolamine and cobalt Ion coordination, the increase in coordination, cobalt leaching rate increases. In the carbide cutting tool, cobalt is a binder phase, tungsten carbide is a hard phase, cobalt leaching can also lead to tungsten carbide particles fall off, so that the tool damage.

2.2 sodium carbonate solution immersion carbide tool experimental results and analysis, at room temperature and 150 ℃ when the carbide cutting tools in sodium carbonate solution before and after soaking energy spectrum analysis results shown in Table 3, Table 4 below. The data show that sodium carbonate solution has no leaching effect on cobalt in cemented carbide tool. At high temperature, the effect of sodium carbonate solution on tungsten leaching of cemented carbide tool is obvious.

The sodium carbonate solution erodes the blade, and when the temperature rises, the surface of the blade forms a large number of pitting. Sodium carbonate on the surface of carbide tungsten carbide extraction mechanism: sodium carbonate solution containing ionic bonds and carbon and oxygen covalent bond, tungsten carbide contains tungsten carbon ion bonds, so the solution contains both tungsten carbon ion bonds and carbon and oxygen Price key. When the solution is heated, because the bond of the ionic bond is stronger than the covalent bond, the tungsten carbon ion bond is first broken, and after the fracture, the tungsten atom is combined with the oxygen atom to form tungsten trioxide, which causes the leaching of tungsten. Water molecules are covalent compounds, hydrogen atoms and oxygen atoms in the form of covalent bond, sodium carbonate is a strong base weak acid salt, sodium carbonate to join, can promote the ionization of water molecules, so that oxygen ions increased. When the temperature rises, it promotes the ionization of the molecules, produces more tungsten ions and oxygen ions, and accelerates the free ion movement in the solution. The tungsten ions are more in contact with the oxygen ions, and the oxidation of the tungsten carbide on the blade surface is intensified. Tungsten trioxide increased, resulting in a large number of tungsten leaching.

2.3 benzotriazole solution immersion carbide cutting tool experimental results and analysis, it is shown that: different temperatures, benzotriazole solution on the carbide cutting tools in the cobalt and tungsten have a good inhibitory effect. Benzotriazole solution after immersion in the surface of carbide tool, carbide blade was benzotriazole solution soaked, the tool surface covered with a layer of film. The inhibition mechanism of benzotriazole solution for cobalt and tungsten in cemented carbide tools: The benzotriazole has the formula: C6H5N3, which is an organic heterocyclic compound containing three nitrogen atoms, of which the nitrogen atom Lonely electrons can work with metal. The -N = N-group in the benzotriazole molecule has a good electron-withdrawing ability, and the nitrogen-containing ring contains three nitrogen atoms. The lone pair electrons of the nitrogen atom are liable to interact with the empty orbit provided by the tool surface element Forming a complex, forming an insoluble protective film which, on the one hand, separates the blade surface from the external medium and, on the other hand, inhibits the dissolution of the tungsten trioxide in the alkaline environment on the surface of the blade, Reducing the oxidation of dissolved tungsten carbide in the inner layer [10]. The cobalt atoms in the cemented carbide tool are free orbit, which can be combined with the lone pair electrons provided by the nitrogen atom to form the coordination compound. Benzotriazole is adsorbed on the surface of the cemented carbide tool by the coordination bond on. The complexes formed are insoluble and they will adsorb on the surface of the cemented carbide tool. As the ligand increases, these complexes form a deposited film on the surface of the cemented carbide tool. It was found that the surface of the cemented carbide blade in the benzotriazole solution was soaked yellow, which was because the color of the complex film produced by the benzotriazole and cobalt cobalt ions was light yellow. Therefore, the inhibition mechanism of benzotriazole can be considered as: the reaction group on the benzotriazole molecule and the metal ion interaction insoluble complex film formed during the etching process, and further polymerize on the metal surface to form a precipitation protective film, thus preventing the Carbide cobalt leaching.

3 Conclusion: 1) triethanolamine solution will make the carbide cutting tool cobalt leaching. Triethanolamine can make cobalt leaching is due to triethanolamine can form complex with cobalt, this complex into the solution, leading to cobalt carbide leaching. Cobalt is a binder phase, and leaching of the binder phase can also lead to the shedding of hard tungsten carbide.

2) Sodium carbonate solution at high temperature accelerates water ionization and promotes the formation of tungsten trioxide on the surface of cemented carbide tool, resulting in the leaching of tungsten carbide in carbide cutting tools.

3) The solitary electrons in the benzotriazole can be complexed with the metal to form a ligand and are insoluble. These ligands are adsorbed on the surface of the cemented carbide tool and form a layer of precipitating film that serves as a protective tool Role, inhibit the carbide cutting tools in the cobalt and tungsten carbide leaching.

2017 - 2022 Global and China tungsten carbide powder industry research and analysis of the status quo and development trends forecast report

"2017 - 2022 global and China tungsten carbide powder industry research and analysis of the status quo and development trend forecast report" content is rigorous, informative, by adding a large number of intuitive charts to help tungsten carbide powder enterprises to accurately grasp the development trend of tungsten carbide powder industry, the correct development Tungsten Carbide Enterprise Development Strategy and Tungsten Carbide Investment Strategy.

  • Chapter 1 Overview of Tungsten Carbide Industry
  • Section 1 definition of tungsten carbide powder
  • Section II Classification of Tungsten Carbide Powder
  • Section III Application of tungsten carbide powder
  • Section 4 Structure of Tungsten Carbide Industry Chain
  • Section 5 Analysis of the news of tungsten carbide powder industry news

  • Chapter II tungsten carbide powder industry development environment
  • Section 1 Analysis of Economic Environment for Development of Tungsten Carbide Powder Industry
  • Section 2 Analysis of the social environment of tungsten carbide powder industry development
  • Section III Analysis of Tropical Tungsten Powder Industry Development Policy Environment
  • Section IV analysis of tungsten carbide powder industry development technology environment

  • Chapter III Analysis and Forecast of Supply and Demand of Global Tungsten Carbide Powder Industry
  • Section 1 Global distribution of tungsten carbide powder manufacturers
  • Section II of the world's major manufacturers of tungsten carbide powder products
  • Section III 2012-2016 global tungsten carbide production capacity in major areas,production statistics Analysis of demand for tungsten carbide powder in major areas of the world from 2012 to
  • Section 5 2017 - 2022 Global Tungsten Carbide Production Capacity and Yield Forecast
  • Section 6 2017 - 2022 Forecast of demand for tungsten carbide powder in major global regions

  • Chapter IV China tungsten carbide powder industry supply and demand analysis, forecast
  • Section 1 China tungsten carbide powder industry manufacturers distribution
  • Section II China's major manufacturers of tungsten carbide powder manufacturers
  • Section III 2012-2016 China tungsten carbide powder industry capacity, production statisticsAnalysis on the Demand of China 's Tungsten Carbide Industry in the Second Quarter of 2012-2016
  • Section 5020-2020 China Tungsten Carbide Industry Capacity and Yield Forecast
  • Section 6 2017 - 2022 China Tungsten Carbide Industry Demand Forecast

  • Chapter 5 China tungsten carbide powder industry import and export situation analysis, forecast Analysis on the import and export of China 's tungsten carbide powder industry in the first quarter of
  • First, the tungsten carbide powder industry imports
  • Second, the tungsten carbide powder industry exports
  • Section 2 2017 - 2022 China tungsten carbide powder industry import and export situation forecast
  • First, the tungsten carbide powder industry import forecast
  • Second, the tungsten carbide powder industry export forecast Section III of the main factors affecting the import and export of tungsten carbide powder industry

  • Chapter 6 China tungsten carbide powder industry overall development
  • Section 1 China tungsten carbide powder industry scale analysis
  • First, the scale of tungsten carbide powder industry unit analysis
  • Second, the scale of tungsten carbide powder industry personnel analysis
  • Third, the tungsten carbide powder industry asset size analysis
  • Fourth, the tungsten carbide powder industry market size analysis
  • Five, tungsten carbide powder industry sensitivity analysis
  • Section II China Tungsten Carbide Industry Financial Capability Analysis
  • First, the tungsten carbide powder industry profitability analysis
  • Second, the tungsten carbide powder industry solvency analysis
  • Third, the tungsten carbide powder industry operating capacity analysis
  • Fourth, the development trend of tungsten carbide powder industry

  • Chapter 7 Analysis of Key Regional Development of China Tungsten Carbide Industry
  • First, China's tungsten carbide powder industry focus on regional market structure changes
  • Second, the key areas (a) tungsten carbide powder industry development analysis
  • Third, the key areas (2) tungsten carbide powder industry development analysis
  • Fourth, the key areas (three) tungsten carbide powder industry development analysis
  • Fifth, the key areas (four) tungsten carbide powder industry development analysis
  • Sixth, key areas (five) tungsten carbide powder industry development analysis

  • Chapter 8 Carbide tungsten powder industry segmentation product market research The first section of the breakdown of products (a) market research
  • First, the development of the status quo
  • Second, the development trend forecast Section II breakdown of products (b) market research
  • First, the development of the status quo
  • Second, the development trend forecast

  • Chapter 9 tungsten carbide powder industry, the downstream market research and analysis _ subscribe to heat, line ,, 010-, 66,18,109,9
  • Section 1 Tungsten Carbide Industry Upstream Research
  • First, the status of industry development
  • Second, industry concentration analysis
  • Third, the industry trends forecast Section II tungsten carbide powder industry downstream research
  • First, the concern factor analysis
  • Second, the characteristics of demand analysis

  • Chapter 10 China tungsten carbide powder industry product price monitoring
  • First, the market price characteristics of tungsten carbide powder
  • Second, the current market price of tungsten carbide powder review
  • Third, the impact of tungsten carbide powder market price factors analysis
  • Fourth, the future tungsten carbide powder market price trend forecast

  • Chapter 11 Analysis of Key Enterprises in Tungsten Carbide Industry The first section of key enterprises (a)
  • First, the enterprise profile
  • Second, the main business products
  • Third, the enterprise sales network
  • Fourth, the business situation analysis
  • Fifth, enterprise development planning Section II key enterprises (b)
  • First, the enterprise profile
  • Second, the main business products
  • Third, the enterprise sales network
  • Fourth, the business situation analysis
  • Fifth, enterprise development planning Section III key enterprises (3)
  • First, the enterprise profile
  • Second, the main business products
  • Third, the enterprise sales network
  • Fourth, the business situation analysis
  • Fifth, enterprise development planning Section IV key enterprises (four)
  • First, the enterprise profile
  • Second, the main business products
  • Third, the enterprise sales network
  • Fourth, the business situation analysis
  • Fifth, enterprise development planning Section 5 Key Enterprises (5)
  • First, the enterprise profile
  • Second, the main business products
  • Third, the enterprise sales network
  • Fourth, the business situation analysis
  • Fifth, enterprise development planning Section 6 Key Enterprises (6)
  • First, the enterprise profile
  • Second, the main business products
  • Third, the enterprise sales network
  • Fourth, the business situation analysis
  • Fifth, enterprise development planning

  • Chapter 12 Analysis of Tungsten Carbide Enterprise Development Strategy Section 1 Market Analysis of Tungsten Carbide Powder
  • First, the tungsten carbide powder price strategy analysis
  • Second, the tungsten carbide powder channel strategy analysis Section 2 Analysis of Tungsten Carbide Sales Strategy
  • First, the media selection strategy analysis
  • Second, product positioning strategy analysis
  • Third, corporate propaganda strategy analysis
  • Section III to improve the competitiveness of tungsten carbide powder business strategy
  • First, to improve China's tungsten carbide powder enterprise core competitiveness of the countermeasures
  • Second, tungsten carbide powder enterprises to enhance the competitiveness of the main direction
  • Third, the factors that affect the core competitiveness of tungsten carbide powder enterprises and enhance the way
  • Fourth, to improve the competitiveness of tungsten carbide powder business strategy The fourth quarter of China 's tungsten carbide powder brand strategy
  • First, the significance of the implementation of brand strategy for tungsten carbide powder
  • Second, the tungsten carbide powder brand analysis of the status quo
  • Third, China's tungsten carbide powder brand strategy
  • Fourth, tungsten carbide powder brand strategy management strategy

  • Chapter 13 Analysis of Investment Situation and Development Prospect of Tungsten Carbide Industry
  • Section 1 Analysis of Investment in Tungsten Carbide Industry
  • First, the overall investment structure of tungsten carbide powder
  • Second, the scale of investment in tungsten carbide powder situation
  • Third, the growth rate of tungsten carbide powder investment
  • Fourth, tungsten carbide powder investment in different areas Section II Analysis of Investment Opportunity of Tungsten Carbide Industry
  • First, tungsten carbide powder investment project analysis
  • Second, you can invest in tungsten carbide powder mode
  • Analysis of Investment Opportunity of Tungsten Carbide Powder in 2017
  • Fourth, 2017 tungsten carbide powder investment in new directions

  • Chapter 14 Tungsten Carbide Industry Entry Barriers and Risk Control Strategies
  • Section 1 Analysis of barriers to entry of tungsten carbide powder industry
  • First, technical barriers
  • Second, talent barriers
  • Third, the brand barriers
  • Section II. Zhi .. Lin: Tungsten Carbide Industry Investment Risk and Control Strategy
  • First, the tungsten carbide powder market risk and control strategy
  • Second, the tungsten carbide powder industry policy risk and control strategy
  • Third, the tungsten carbide powder industry business risk and control strategy
  • Fourth, tungsten carbide powder industry competition risk and control strategy
  • Fifth, the tungsten carbide powder industry, other risks and control strategies

  • Chapter 15 Tungsten Carbide Industry Research Conclusion

Field2activated Pressure2assisted Combustion Synthesis of Tungsten Carbides under Electric Field

【Abstract】FAPACS process , which combines the simultaneous synthesis and densification of materials , was utilized to produce tung2 sten carbides material from tungsten and carbon powders with different mole ratios between them , i. e. W + 1. 0C , W + 1. 1C , W + 1. 2C and W + 1. 3C. The shrinkages after the synthesis reaction were measured. The effects of the temperature , the reactant compositions and dif2 ferent carbon sources on the product compositions , densities and Vickers hardness were investigated. The end2product relative densities ranged from 81. 1 % to 89. 9 %. Vickers hardness measurements on the dense samples gave values ranging from 731kg·mm- 2 to 423kg· mm- 2 .

【Key words】combustion synthesis ; tungsten carbide ; field activation

Tungsten carbide has a high melting point (260022850 ° C), high hardness (16222GPa), high fracture toughness (28MPa m1Π2) and high compressive strength (5GPa, 20 ° C) and other excellent properties, widely used in tool materials and wear parts. Tungsten carbide materials generally use a multi-step preparation process, including product synthesis, grinding, molding and sintering, to obtain a dense material. However, this high-temperature long-term treatment tends to cause severe grain coarsening, resulting in the loss of fine grain structure and the associated mechanical properties. It is therefore necessary to carefully control the parameters during the sintering process, Time to reduce grain growth, a way to promote densification and to avoid excessive grain growth is the so-called rapid sintering technology.

Self-propagating high-temperature synthesis is a very promising and energy-saving advanced material preparation technology [1]. Typical solid-solid phase self-propagating high-temperature synthesis process, at the end of the powder mixture briquetting reaction, the use of self-reaction process The reaction heat is released to maintain the reaction. Although this method has the advantages of energy saving and high efficiency, but the synthesis of materials is often not dense, for the development of a combination of mechanical pressure and combustion synthesis method, and use it to prepare dense materials, but this technology is generally limited to High reaction temperature or adiabatic temperature of the reaction system, and for other thermodynamic factors (the performance of the lower reaction enthalpy or adiabatic temperature) of the reaction system there are some limitations. In the tungsten 2-carbon system, the adiabatic temperatures of the two carbides (WC and W2 C) are 1127 ° C and 673 ° C, respectively, which are significantly lower than theoretically self-propagating high-temperature synthesis reactions. Temperature 1527 ° C, in the absence of activation, tungsten carbon reaction can not start. In recent years, a method called Field2 Activation Combustion Combustion Synthesis (FA2 PACS) has been developed. It is also a rapid sintering technique that completes the synthesis of materials by using electric field and pressure. Densification has been successfully used to prepare ceramic, metal and intermetallic compounds [226], which have been able to produce dense nanomaterials by making appropriate improvements In the process of synthesis, the electric field has a significant effect on the reaction kinetics (eg reaction rate and reaction mechanism) and the properties of the product (such as the phase composition of the composite and the elemental distribution in the solid solution). These effects are related to some phenomena under the action of the electric field And electromigration to promote mass transfer, etc.)

Tungsten carbide is present in several different phases, most notably WC and W2C, and most of the tungsten carbide powder is usually a mixture of WC and W2C, so it is necessary to carry out the study of the synthesis of single phase tungsten carbide from element reactants The There are no reports on the preparation of tungsten carbide by FAPACS technology. In this study, we used FAPACS technology to prepare dense tungsten carbide materials, and studied the effects of various process parameters such as the C / W ratio, the reaction temperature and the reaction of different carbon sources on the composition, density and Vickers hardness of FMCACS prepared by FAPACS.

Tungsten and carbon with different molar ratios of 1: 1, 1: 1. 1, 1: 2 and 1: 3 were used to prepare tungsten carbide, two 99.9% pure carbon powder as carbon source, one Is 20 μm of activated carbon (Kojondo Chemical Co.) and the other is 20 nm of carbon black (Korea Tungsten Co.), respectively, and purity of 99.9%, particle size 0. 6μm tungsten powder (Korea Tungsten Co.) in the oxidation Aluminum ball mill for dry grinding. After mixing, weigh a certain amount of mixture, into the graphite mold (die diameter 45mm, diameter 20mm, height 40mm), embedded in the mold graphite silk, and then under the pressure of 0. 4MPa pressure for about 2 minutes into pieces, The sample is then placed in a FAPACS device and the device is shown in Figure 1. The experiment is carried out according to the following steps: The first step is to evacuate the whole system to 2 × 10 - 2 Torr, the second step with 6MPa single shaft pressure, the third step will be 27V and 3000A DC current added to the mold of two graphite The head, Joule heats the mold and the sample up to the desired temperature, which can be obtained by measuring the optical thermometer on the surface of the graphite mold. At the same time, the pressure was densified and the pressure was maintained until the sample reached the density, which was measured by a linear gauge, and the final sample was cooled to room temperature at a rate of 600 ° C / min.

After the reaction, remove the sample from the mold and gently remove the graphite from the surface of the sample. The sample was then ground and finely ground on silica sandpaper and then polished on diamond sandpaper. The density of the synthesized product was tested by the Archimedes method. The phase composition and microstructure analysis of the product were carried out by X-ray diffraction, scanning electron microscopy and electron probe, and the Vickers hardness measurement (1 kg and 10 kg load duration 15s).

For the initial reactants with different tungsten carbon ratios, the shrinkage of the sample during the FAPACS process and the change in the surface temperature of the mold over time are shown in Fig. 2 for W + 1. 1CA, W + 1. 2CA and W + 1. 3CA. In Figures 2 and below, subscripts A and B represent activated carbon and carbon black, respectively. The sample was gradually shrunk up to about 850 ° C and then accelerated at this temperature. When the stoichiometric mixture is heated to 850 ° C at a pressure of 6 MPa, no reaction occurs, as can be seen from the XRD analysis shown in Figure 3, where only the diffraction peak of the reactants indicates that tungsten and carbon no response. But when the temperature rises to 1250 ° C, the reaction occurs to form tungsten carbide, as can be seen in Figure 4. At the same time from the XRD analysis results also see that there are some W2 C in the reaction product, so to get WC, in the mixture need to add excess carbon. For W + 1. 1CA and W + 1. 2CA systems, the sample shrinks initially slowly and becomes severe after 5 seconds. In contrast to the above, the sample shrinkage of the W + 1. 3CA system has been slow and drastic, which is due to the disadvantage of material densification due to excessive carbon in the reactant system. Table 1 shows the density, sample volume, and volume change values ​​for samples at different stages during tungsten carbide synthesis and densification. The results show that for the W + 1. 1CA system, approximately 2.85% of the total volume of contraction occurs before the reaction, while the total volume of 97. 15% shrinks occurs during the reaction and densification stages, and for other systems , These values ​​were 2. 76% and 97. 24% (W + 1. 2CA system), 2.97% and 97. 03% (W + 1. 3CA system). The relative densities of the synthesized products of the three systems were 84.2%, 84.1% and 81.1% of the theoretical density, respectively. With the increase of the ratio of tungsten to carbon in the reactant system, the relative density of the combustion products decreases, which may be related to the fact that there are many large particles of carbon in the product which are not conducive to the densification of the samples. The corresponding XRD results of each system are shown in Fig. W + 1. 3CA and W + 1. 1CA system, W2 = 3CA and W + 1. 2CA system reaction is complete, W2 C is not detected in the combustion products, For W + 1.CA system, WC is the main phase, but still found in the combustion products of some W2C.

The relative densities of the synthesized products were 89.9%, 89.3% and 88.6% of the theoretical density, respectively. The effect of different tungsten carbon ratios on the density of the product was the same as that of activated carbon as carbon source. The XRD results of the combustion products of these systems are shown in Fig. 7, and as the carbon content of the reactants increases, the degree of complete reaction increases. In all systems, the carbides in the combustion products are essentially single-phase WC. W + 1. 3CB and W + 1. 2CB The product of the reaction system is only WC single phase, and for W + 1. 1CB system, only trace amounts of W2 C exist in the combustion products, High reactivity, so to synthesize a single phase of WC requires less carbon.

Introduction of Tungsten Carbide - Steel Wear Resistant WCSP

【Abstract】This paper introduces the performance, characteristics and application fields of tungsten carbide-steel wear resistant products developed by Beijing Yongguang Express Surface Alloy Technology Co., Ltd. The use of high-energy ion implantation technology can make tungsten carbide injection into the steel base parts of the matrix, greatly improving the parts of the wear resistance, strength, hardness and toughness, can be widely used in many fields, this result is called steel Surface modification technology and parts of the surface modification technology an important breakthrough.

【Key words】tungsten carbide; high energy ion implantation; abrasion resistance

In the development of modern science and technology and industrial production, many important mechanical equipment and mechanical parts in harsh working conditions, such as high speed, high temperature, high pressure, heavy load, so the mechanical parts due to wear, corrosion, oxidation The destruction often occurs. According to authoritative statistics, in the failure of mechanical parts, there are "(belonging to metal wear, resulting in frequent parts replacement and maintenance, increased energy consumption, reduced efficiency of mechanical equipment, increased costs, restricting the development of production.

Friction and wear caused by steel damage, mostly from the steel surface. The use of surface protection measures to delay and control the surface damage, has become an effective way to solve the problem of mechanical parts wear and tear. Therefore, a variety of mechanical parts surface anti-wear technology came into being, such as plating (hard chrome plating), hot-dip plating (carburizing, nitriding, infiltration of metal), thermal spraying (wear-resistant alloy or ceramic) Wear-resistant alloy or tungsten carbide, coating) physical and chemical vapor deposition, ion plating), paste hardened carbide, ceramic, rubber, high energy beam laser or electron beam welding, ion implantation. These surface modification techniques have their own characteristics, each show, but there are many inherent deficiencies: such as hot carburizing in the carburant on the material selection is narrow, wear resistance is not enough; nitriding nitride layer is too thin; traditional osmotic metal Low efficiency; chrome plating, thermal spraying, surfacing, paste hardening layer, although the wear resistance is good, to adapt to a wide range, but there is a low bonding strength with the matrix interface, the interface is easy to produce wear-resistant layer off and lose The wear-resistant layer is too thin, the cost is too high; high-energy beam welding wear layer to adapt to a wide range, but the destruction of the workpiece surface, easy to produce cracks, engineering costs. Therefore, many units in need of wear-resistant materials are eager to study the production of an economical high-level wear-resistant materials.

Introduction to Tungsten Carbide - Steel Wear Resistant: Beijing Yongguang Express Surface Technology Co., Ltd. successfully developed a kind of tungsten carbide a steel wear-resistant products) hereinafter referred to as "the product wear-resistant high, in a variety of wear mechanical parts can be used, the product Asked World, on the much-favored by the machinery industry. Tungsten Carbide - Steel Wear Resistant is the use of high-energy ions will be injected into the steel matrix WC injection, the surface of the formation of high wear resistance of the tungsten carbide enrichment layer and a special organizational structure. WC is a high hard ceramic material, hard and brittle, in addition to grinding materials, WC rarely used directly. In the century, scientists invented WC-based cemented carbide, as a tool, mold, measuring tools and drilling materials, the wear resistance of high-speed steel 15-20 times, to achieve a tool revolution. When other industries want to use tungsten carbide based hard alloy as wear-resistant materials, found that the use of powder metallurgy method of manufacturing carbide, the need for special presses and sintering furnace, it is impossible to create the engineering industry expected large size and complex shape Parts. In addition, the hard alloy wear resistance is high, but the toughness is poor, higher brittle, more expensive. These factors make the carbide in addition to work, volume, mold, drilling tools are well used in other mechanical products are less applied. In order to apply the cemented carbide to other mechanical products, the engineering industry has developed a tungsten carbide surfacing technology to solve some of the complex shape of the surface parts of the anti-wear problems. However, the tungsten carbide surfacing process is complex, surfacing layer surface roughness is high, there are many pores in the surfacing layer, the use of easy to fall off in many places of use can not achieve the effect of high wear and tear of tungsten carbide. Beijing Yongguang Express Surface Technology Co., Ltd. at home and abroad take the lead in the use of high-energy ion injection technology, in a variety of complex shape parts of the steel matrix injection of tungsten carbide, with high wear resistance of the tungsten carbide enrichment layer Can reach 0.3-0.5mm, tungsten carbide hardened layer to 1-1.5mm. The product has a high hardness, high strength, high toughness, especially wearable. It is a steel surface modification technology, mechanical parts surface modification process technology an important breakthrough, to fill the domestic and foreign hard wear-resistant materials of a blank, with the international advanced level.

Tungsten Carbide - Steel Wear Resistant good comprehensive mechanical properties and high wear resistance of tungsten carbide injection into the steel matrix, the formation of metallurgical bonding, the respective concentrations of gradient changes, there is no macro interface, the formation of a special organizational structure, both tungsten carbide and steel matrix advantages Complementary, its surface has a high hardness of tungsten carbide, high wear resistance, high fatigue resistance, the heart has a high strength of steel matrix, high toughness. The surface hardness is based on customer requirements and the properties of the selected steel substrate HRC45-64 changes between. Tungsten Carbide - Steel Wear Resistant hardness is not the only factor to measure wear resistance, soft matrix WC also has wear resistance, but slightly worse than the hard matrix wear resistance. In the metallurgical, power, building materials and other industries under a variety of severe wear conditions, Tungsten Carbide - Steel Wear Resistant tungsten carbide hardening layer thickness, although only between 1-1.5mm, but have shown a good comprehensive mechanical properties and high wear Sex, the service life of the original wear-resistant materials to 3-10 times, and some to -, more than. Numerous practices have proven that Tungsten Carbide - Steel Wear Resistant has a high wear resistance, but theoretical research is lagging behind practice. At present, some of the theory of metal and anti-wear theory, why Tungsten Carbide - Steel Wear Resistant has such a high wear resistance, can not get a satisfactory explanation, to be further studied theoretically.

Good craftsmanship: Tungsten Carbide - Steel Wear Resistant production process is: the steel as raw material, the mechanical processing to create a variety of parts, through high-energy ion injection technology, in these parts surface injection into the WC. Product shape is not restricted, the workpiece size range is wide, large parts can be injected in the tungsten carbide after welding assembly. Injection process and thermal spraying, surfacing and other processes are very different, in the injection, the workpiece surface roughness is not destroyed. Injection pressure at a certain temperature, the workpiece accuracy is slightly reduced, but due to high-energy ion implantation technology formed by the injection layer thick, even after a small amount of grinding and other finishing, but also to maintain high wear resistance. In the high-energy ion injection process, the customer requirements of those parts of the fast wear, can increase the WC content, the customer does not need some parts of the anti-wear, but also less infiltration or no injection. Due to the good craftsmanship of Tungsten Carbide - Steel Wear Resistant products, it has been widely used in wear and tear equipment in many industries, which not only improves the life of the equipment, but also solves many technical problems and key problems for these industries.

High cost performance Currently widely used high-chromium or rare earth wear-resistant alloy steel, castles are cumbersome. Spraying ceramic or surfacing tungsten carbide, in order to prevent the deformation of the process also need thicker steel matrix. Tungsten Carbide - Steel Wear Resistant products are resistant to wear 1-1.5MM thick tungsten carbide and the high hardness and special structure to achieve, the thickness of the steel matrix only need 8-20MM, so that in order to counterfeit the purpose of doing heavy equipment has become light, the cost of materials , Installation and maintenance costs are reduced. Tungsten Carbide - Steel Wear Resistant products through a variety of conditions under the wear test, as well as more than 100 different customers in the actual use of the results show that: according to different working conditions, Tungsten Carbide - Steel Wear Resistant wear life is 4-15 times hardened tool steel, Material 3-8 times. Light weight, long life, less maintenance, to ensure long-term safe operation of production. Therefore, its performance and price ratio is significantly higher than other wear-resistant materials, the use of Tungsten Carbide - Steel Wear Resistant instead of the traditional wear-resistant materials for our customers will bring good economic benefits.

It is suitable for all kinds of mechanical products under strong wear and tear. These products are mainly concentrated in mining, metallurgy, cement, electric power, coal, petroleum, chemical industry, engineering, transportation, light industry. And other industries, in the past these industries in a strong place to wear a suitable wear-resistant materials, switch to Tungsten Carbide - Steel Wear Resistant, its life increased several times to several times, the effect of the vast number of customers feel magical. Such as a blast furnace blast furnace material slip The use of Tungsten Carbide - Steel Wear Resistant, after the use of Tungsten Carbide - Steel Wear Resistant, than the original material life increased by 20 times; a cement group vertical grinding, the original welding 10mm thick tungsten carbide, switch to Tungsten Carbide - Steel Wear Resistant, life increased by 8 times; a thermal power plant fluidized bed boiler slag And elbow, switch to Tungsten Carbide - Steel Wear Resistant, its life increased by 15 times. Therefore, Tungsten Carbide - Steel Wear Resistant worthy of the need for anti-wear materials in the various machinery industry to promote the application.