Posted by: hannahgwendolyn at 09:28 AM | No Comments | Add Comment
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Superfine cemented carbide is known as "three high alloys" for its high toughness, high strength and high hardness at the same time. It is widely used in the manufacture of microdrill, dot matrix printer, precision die, glass precision cutting, textile cutting and so on. However, in order to obtain high-performance ultra-fine cemented carbide and further improve the mechanical properties of WC cemented carbide, it is necessary to control the grain size of WC. Therefore, how to obtain uniformly distributed ultra-fine WC powder or wc-co composite powder has become a hot spot of current research. Tungsten carbide can be produced in various ways. The traditional tungsten carbide production method is made from solid carbon tungsten carbide powder, which can produce tungsten carbide powder with particle size of 1 ~ 30 m. Direct reduction carbonization technology is a kind of technology to prepare WC powder, which has the advantages of low production cost, simple process and high purity of the product. Japan sumitomo electric co., ltd. USES WO3+C powder to directly and continuously reduce carbon in a hydrogen-atmosphere rotary furnace to produce ultra-fine WC powder. Ultrafine WC powder 0.1 m was prepared by direct reduction carbonization of WO3 and carbon black. In this paper, WO3 and carbon black are used as raw materials to prepare ultra-fine WC powder by direct reduction carbonization technology, and the reaction temperature and holding time in the process of reduction carbonization are studied.

Ultra-fine grain cemented carbide has high hardness and high strength, and is widely used in the manufacture of microdrill bits, dot matrix printer needles and precision tools for the drilling of integrated circuit boards. Ultrafine tungsten carbide powder is an important raw material for the preparation of ultrafine cemented carbide. At present, the reports of preparing nanometer, ultrafine tungsten carbide powder, or the way of the composite powder is more, there are mainly tungsten oxide reduction carbonization method (that is, the traditional process), directly carbonized tungsten oxide method, plasma chemistry carbonation method, halide tungsten carbide method, since the reducing amine salt, high frequency plasma method, gas solid instead should method, freeze drying, etc. These methods, the traditional process is simple and easy, reasonable, stable and reliable, large production capacity and advanced products are of good quality, low cost and efficiency higher advantages, and is closely related with tungsten carbide production in our country, is a kind of conform to China's national conditions, more province industrial production method, the traditional process made BET size is less than 0.2 microns ultrafine tungsten carbide powder as the U.S. DOW company is the quality of the production of the tungsten carbide powder. However, other methods still have disadvantages such as complicated process, high production cost, low efficiency and many impurities, which are suitable for industrial scale production.

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Posted by: hannahgwendolyn at 09:46 AM | No Comments | Add Comment
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Wear is one of the three major failure modes (wear, corrosion and fracture) of metal mechanical parts. Modern industry urgently needs workpieces that can work effectively under severe wear conditions (such as high temperature, high speed friction and wear, etc.). Compared with traditional metal abrasion resistant materials, ceramic particle reinforced metal matrix surface composites effectively combine the high strength and toughness of metal materials with the high hardness of ceramic particles to form a high-performance material with overall impact resistance and surface abrasion resistance, which has attracted extensive attention. Among them, tungsten carbide particle reinforced steel matrix surface composite has the advantages of price, performance and technology. This paper reviews the research and application of tungsten carbide particle reinforced steel-based wear-resistant composites at home and abroad. Tungsten carbide (WC) is hexagonal crystal, with high hardness, high melting point, small thermal expansion coefficient, good wear resistance, and so on. Moreover, the wetting Angle of the liquid iron and steel encapsulates the tungsten carbide particles, which can support and protect the tungsten carbide particles. Almost all steel materials can be used as the matrix of casttungsten carbide reinforced particles due to the good forming properties of molten steel and complete wetting of tungsten carbide particles. However, the specific choice of steel or iron matrix should be based on the corresponding operating conditions (temperature, stress, wear resistance, etc.) to choose.

At the same time, tungsten carbide granule reinforced local composite material of steel matrix was designed and prepared. Low chromium cast iron, nodular cast iron, cast steel, gray cast iron and other steel materials were selected as bulk materials to study their composite effect. The composite process and casting process were improved and optimized, and were applied to the local composite of the worn surface of the flow parts of slurry pump. The microstructure and formation mechanism of the composite layer were analyzed, and the erosion wear properties of the composite material were investigated and compared with that of high chromium cast iron (Cr15Mo2).

It turns outthat the water glass sand mold (core) plus negative die casting infiltration technology can achieve complex surface (surface) the preparation of particle reinforced composites, pouring method is simple and reliable, in less than 10 mm, base material thickness of composite layer thickness can reach 3 ~ 7 mm, and the composite layer less casting defects, the composite effect is good, high density and interface bonding strength, material organization is divided into the base material area, transition area and complex area, uniform distribution in composite layer of tungsten carbide particles in high chromium cast iron substrate and grain shape intact. The pump chamber and inner cover of the 4' slurry pump produced by the module compaction pulverization process have basically realized the local composite of the whole worn surface. Grey cast iron with low chromium cast iron casting temperature is 1550~ 1600degreescan get composite good surface composite material, relatively ideal effect.

Posted by: hannahgwendolyn at 09:43 AM | No Comments | Add Comment
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Thermosetting hammer thermal spray powder coatings is also called the art type of powder coating, because coating can form as a hammer blow after the metal surface decorative pattern, this type of powder coatings not only has many advantages of thermosetting powder coating commonly, smooth and beautiful decorative pattern, coating, adornment sex is strong, also can make up and covered the surface rough, uneven defects, such as hammer powder coatings has the colour and lustre downy, coating flexibility, solid and durable, so widely used in instruments and meters, power distribution cabinets, security doors, home appliances furniture, lighting, medical equipment and other fields of metal surface coating.

Hammer pattern powder coating is prepared by using the principle of curing powder coating's melting viscosity, surface tension and curing speed, etc. There are usually several ways to produce hammer pattern powder coatings.

Add packing in the production of hammer powder coatings principle: increase the dosage of packing, or the use of high oil absorption packing, to obstruct the normal flow when the resin melt, the resin can not fully inclusive or just package appearance filler particles, no excess resin to fill the space between the fillers particles, thus forming the skeleton of the three-dimensional structure for fillers particles.

Using this method need to pay attention to is: different filler oil absorption is different, generally to achieve the same volume concentration, small density, small particle size than the surface area and large oil absorption yan filler amount. The advantage of the hammer grain produced by this method is that its cost is low, but if the amount of filling is not controlled properly, the powder coating construction performance, coating film mechanical properties, chemical resistance properties will be affected. In general to use this method to produce high efficiency and good stability of the product, the production process can be made some adjustments.

Join incompatible material production hammer powder coating is to point to: add some incompatible polymer inthermal spray powdercoating, its melting point higher than the melting temperature of powder coating resin binders, powder coating containing incompatible premixed by melt extrusion with other resin curing agent are incompatible, curing film when constitute the basic material of resin coating on the polymer particles, forming a texture. This method should pay attention to the need to strictly control the types of incompatible substances and the amount of additives, otherwise the mechanical properties of the coating will be affected. The hammer pattern powder coating produced by this method has good chemical and corrosion resistance.

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Posted by: hannahgwendolyn at 09:51 AM | No Comments | Add Comment
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Anodic oxidation, electrophoretic coating and powder spraying are the main surface treatment methods of aluminum profiles. Each method has its own advantages and occupies a considerable market share. But if you want to divide the high and low, personally think or spraying powder dominant, what are the advantages?

Advantage 1

The process is relatively simple, mainly due to the improvement of the automatic precision of the main equipment in the production process, some of the main technical parameters have been able to achieve microcomputer control, effectively reducing the difficulty of process operation, while greatly reducing the auxiliary equipment;

Advantage 2

High yield, in general, if the appropriate measures, can maximize the control of nonconforming products;

Advantage 3

The energy consumption is obviously reduced. In the production process of ordinary anodic oxidation and electrophoretic coating, the consumption of water and electricity is quite large, especially in the oxidation process. The output current of the rectifier can reach 8000~11000A, and the voltage is between 15~ 17.5v. In addition, the heat consumption of the machine itself needs to be constantly cooled by circulating water. The power consumption per ton is usually around 1000 degrees.

Advantage 4

The pollution degree of water and air is reduced, the use of flake alkali, sulfuric acid and other liquid organic solvents is no longer used, reduce water and air pollution, but also effectively improve the competitive strength of aluminum profile and as an environmental protection product of plastic steel profile, reduce some production costs accordingly;

Advantage 5

The labor intensity of workers has been significantly reduced, because the use of automated assembly line operations, feeding methods and the use of fixture has been significantly simplified, improve the production efficiency, but also reduce the labor intensity;

Advantages 6

The requirements for the surface quality of raw materials are significantly reduced. The powder coating can completely cover the extrusion lines on the profile surface, cover up some defects on the surface of aluminum profiles, and improve the surface quality of aluminum profiles.

Advantages 7

Some of the physical indicators of the coating film than other surface treatment film has significantly improved, such as hardness, wear resistance, acid resistance, can effectively extend the service life of aluminum profiles.

Powder spraying is powder coating, process is used is electrostatic spraying, the use of electrostatic spray gun, under the influence of accelerating wind, so that the powder particles ejected gun body carrying a positive charge, and with a negative charge profile contact, electrostatic adsorption, and then through high temperature curing. It also enhances the adsorption strength of the coating and prevents the paint film from falling off.

Look from craft itself, have quite tall science and technology composition, allocate the coating of each different color, produce the adornment effect of different color department, accord with the need of indoor adornment more, also be with the application of aluminous profile in bldement to indoor development trend photograph is consistent. In particular, the combined use of spraying profiles and thermal insulation bridge, so that it has a more fashionable trend, thermal spray powder profiles with a greater space for development, but also other processing methods produced by the profile can not be replaced.

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http://www.wococarbide.com/Transaction/en_information.html

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Posted by: hannahgwendolyn at 09:59 AM | No Comments | Add Comment
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