December 29, 2018
The invention relates to a manufacturing method of tungsten carbide ball
Carbide ball grinding equipment at the present time the orbits of the finishing time is long, large dosage of steel ball and low grinding efficiency, the purpose of the utility model aims to provide a kind of hard alloy ball grinding disc, through the improvement of grinding plate of track structure, shorten the track nap time, save steel consumption, and further improve the grinding efficiency of tungsten carbide balls.
In order to achieve the above purpose, the utility model provides a hard alloy ball grinding disc, including an upper grinding disc and a lower grinding disc used with it; The lower grinding disc design has at least two concentric circular orbits that coincide with the center of the lower grinding disc; Each track is designed with a v-groove; The two inner sides of the v-shaped groove face an arc groove with an equal chord length; The center of the circular arc groove coincides with the center of the processed carbide ball, and the radius of the circular arc groove is the same as that of the processed carbide ball.
Using the above carbide ball grinding wheel to be machining carbide ball grinding, semi-finished products, will first grinding and grinding disc under the distribution of the plate is installed on the grinding machine grinding plate and the lower grinding plate, and by using the circular arc groove corresponding to the steel ball finishing orbit, after being met the requirement of the orbital repair, will be machining carbide ball semi-finished grinding disc under load orbit, grinding disc for grinding so as to exert pressure to move up and down the grinding disc counterclockwise involution golden ball grinding process.
In the optimal implementation mode, in order to ensure an ideal contact area between the alloy sphere to be processed and the arc orbit, the chord length of the arc groove is 0.3 ~ 0.35 times of the diameter of the carbide sphere to be processed.
In the optimal implementation mode, in order to separate the two arc tracks and ensure the formation of three-point contact in the processing process, the lower end of the v-shaped groove is provided with a scavaging groove connected with the v-shaped groove, so that even if the arc track is worn for a period of time, the two arc tracks will not be connected, thus extending the service life of the arc track.
To implement the optimal selection of way, in order to guarantee the alloy to be sphere in the machining process inside and outside the orbit of the linear velocity difference greater since the corner.
In the optimal implementation mode, the upper grinding disc is designed with observation holes. During the grinding process, the carbide ball can roll freely in the observation hole to facilitate the observation of its grinding state.
In the preferred embodiment, the upper grinding plate is designed with at least four positioning screw holes for fixing the upper grinding plate on the upper grinding plate of the grinding machine; The locating screw holes are distributed on the locating circle of the upper grinding disc; The positioning circle is designed according to the center of gravity of the upper grinding disc; The observation hole is located outside the locating circle of the upper grinding disc.
In the optimal implementation mode, the axes of the upper grinding disc and the lower grinding disc coincide; The upper grinding disc and the lower grinding disc are both rings and have the same inner and outer diameters.
Described implementation approach, the optimal selection of the grinding plate design has three track, the mill plate along the radial direction by three orbit radius of circular arc groove outside introversion, in turn, increases, so in different size of tungsten carbide ball, without grinding disc replacement, you just need to change different tracks and to save the time for replacing grinding disc, and avoid change caused by different grinding disc repeat positioning accuracy is poor. On the premise of ensuring the equal height of the three types of alloy ball to be processed after loading into orbit, the grinding processing of three different types of alloy ball can be realized at the same time. This grinding method is also applicable to the design of carbide ball grinding disk with more than three orbits.
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December 25, 2018
Marketing Report Analysis of tungsten carbide balls
Tungsten carbide ball is consists of cobalt alloy ball (YG6X YG6 and YG8 YG10, YG13), while the back of the figure represents the cobalt content, such as: YG6 refers to the CO content is 6%, the remaining 94% WC, there is another kind of tungsten nickel alloy ball (YN6 YN8, YN10, YN12), in the same way at the back of the Numbers represent a nickel. The proportion of two kinds of alloy ball in front of the 14.6 15.1, and those for titanium carbide alloy ball ball, weight is lighter.
Ball tooth bit is a kind of rock drill bit which appears with the development of hydraulic rock drill. It has high working efficiency, fast drilling speed and saves auxiliary working time. It is suitable for fast driving of high-power rock drill. Ball tooth drill bit in the drilling of brittle rock, with the use of high power hydraulic drill, the biggest characteristic is fast and stable chisel, drill bit grinding cycle is long. Since the 1970s, porter company has been researching and developing ball-tooth bit as its main product. Now, the sales volume of various ball-tooth bit accounts for 60% ~ 70% of the total production of the ball-tooth bit. In 1968, after adopting the precision hot-setting technology, sandvik company developed a series of ball-tooth drill bits with large and small diameter for percussion drilling, and recommended the ball-tooth drill head as the "ideal supporting drilling tool for hydraulic rock drill". In the next few years, ball tooth bit will take more and more proportion in rock drilling bit market.
After the 1980s, China began to pay attention to the research and development of ball-tooth bit. In the 1990s, the quantity and quality of domestic ball-tooth drill bits have been greatly developed (table 5), and the export volume is also increasing year by year. A batch of ball tooth bit manufacturers with larger output and better quality appeared, such as lianhuashan, chengtan, changsha mining institute, changjiang river, shaodong and so on. Among them, the ball tooth bit produced by lianhuashan takes a large proportion in the export bit.In the production process of ball tooth bit, high quality carbides of shell steel, high precision processing equipment, reasonable processing technology and heat treatment technology are the preconditions to ensure product quality. The ball tooth bit steel used in foreign brazing tool factory mainly USES chrome-nickel-molybdenum steel or silicon-manganese chrome-nickel-molybdenum steel. In the hard alloy aspect, each factory selects the high quality tungsten carbide ball, like Sweden DP series alloy, Germany GT series alloy and so on.
Related link:
http://www.wococarbide.com/Transaction/en_article_info/id/582.html
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December 20, 2018
The role of cast tungsten carbide powder in the wear processing
The wear resistance of different particle sizes of tungsten carbide powder was compared and analyzed. The wear resistance of spray welding layer increased with the decrease of casting tungsten carbide particle size. The reason is: with the decrease of the particle size of cast tungsten carbide, its distribution in the spray welding layer is improved, and the microstructure of the spray welding layer becomes more uniform. On the contrary, the larger the cast tungsten carbide particles are, the larger the gap between them is, and the more easily the abrasive particles invade the base metal and wear it out. The casting tungsten carbide particles are widely spaced, and the scraping action of polygonal quartz sand edges and angles on the soft matrix phase on the surface of the spray welding layer will result in serious wear and tear of the matrix phase, and finally the hard phase particles will fall off due to the loss of the maintenance of the matrix phase. The cast tungsten carbide particles are small and the distance between the particles is small.
Casting tungsten carbide powderplays a key role in abrasion resistance during the process of wear and tear, and the shielding and protection of the softer matrix phase in turn leads to the matrix playing a good holding role relative to casting tungsten carbide alloy powder, so that it will not fall off. In this way, they rely on each other and play their respective roles.
Different kinds of tungsten carbide have great differences in hardness, toughness, cladding performance and so on. One or more mixtures can be reasonably selected as hard ceramic phases according to the working conditions.
Single crystal tungsten carbide can be prepared by mixing tungsten powder with carbon black in a high temperature carburizing furnace. The hardness and toughness of tungsten carbide are between cast tungsten carbide and sintered tungsten carbide. At the same time, it has good wetting property to iron group metals. However, the content of monocrystalline tungsten carbide in the surface composite material should not be too high, otherwise, the phenomenon of bridging monocrystalline tungsten carbide is extremely easy to occur, especially in the laser cladding process. The bonding force between the bridge surfaces is very weak, and it is easy to be damaged from the bridge surface under external load, resulting in spalling of tungsten carbide and reducing wear resistance.
Precautions for health protection of personnel in tungsten carbide powder production workshop
Due to the fact that tungsten carbide powder is a micro powder, the following matters should be noted by relevant personnel in the tungsten carbide powder production workshop:
1. Tungsten carbide dust can cause bronchitis, bronchiolitis, atresic bronchiolitis and atrophic emphysema.
2. Tungsten carbide can cause the proliferative reaction of lymphocytes in the lungs and gradually harden. The walls of the blood vessels thickened and homogenized.
3. Gastrointestinal dysfunction, renal irritation and catarrh inflammation of the upper respiratory tract occurred in people exposed to tungsten carbide dust at work.
Therefore, in the environment with access to tungsten carbide powder, it is necessary to use a gas mask, dust suit, gloves and glasses that meet the requirements. Tungsten carbide powder production in all stages to prevent dust leakage, workers to do pre-employment physical examination, a regular examination every year. When worker upper respiratory tract appears apparent symptom, want to transfer work temporarily, disengage from contact with tungsten. When appear lung sclerosis or outside respiratory function maladjusted, should transfer from the post.
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December 14, 2018
Influence of thermal expansion of wire drawing dies on dimensional accuracy of drawing wire
The thermal expansion of wire drawing diesdiameter has a significant impact on the increase of steel wire diameter. In order to measure the distribution of wire drawing die temperature, drill 4 holes in the wire drawing die and insert thermocouples. The distance between each hole and the steel wire surface is respectively 1.5, 4.5, 11.3, 19.3 mm. The thermal conductivity of mold core and mold sleeve is 97,90 W/mK, respectively. Thermal expansion coefficient are: 4.7 x 10-6 / degrees, 12 x 10-6 / degrees. Lubricants are calcium based SCM 435.
Wire drawing die work half cone Angle 4 degrees~ 10 degrees, drawing speed is 10 ~ 110 m/min. Partial compression rate 11.6% (from 7.90mm to 7.42mm).
Half Angle is 7.5 degrees, the entrance of the wire drawing die wire drawing rate of 110 m/min, wire drawing die temperature within the original 2.5 min grew rapidly and stable 10 min later start, A, B, C, D of each hole temperature: 160150138130 degrees; Surface, 110 degrees.
The increase ratio of wire diameter is defined as h= (d-d)/d * 100, where d is the diameter of the drawing wire and d is the diameter of wiredrawing dies. When h is positive, the diameter of the drawn wire is larger than that of the drawing die. When h is negative, the diameter of the drawn wire is smaller than that of the drawing die. Hd =h-h0. In the production process, the difference between the original diameter of the wire before drawing and the diameter of the stable state is very important, so the diameter increase ratio is defined as hd. In drawing speed 110 m/min, working under the condition of half cone Angle is 7.5 degrees, relationship between hd and quality of wire drawing parameters as follows: the quality of steel wire before 200 kg, with the increase of quality, diameter enlargement ratio gradually increases to 0.1%, quality of steel wire after more than 200 kg of steady at 0.1%.
The temperature of hole A decreases gradually with the increase of the working cone half Angle in the steady state of wire drawing. Work half cone Angle is 4 degreesand 5.5 degreesand 7.5 degreesto 10 degrees, hole respectively A temperature: 175170165160 degrees. The diameter increase ratio was 0.15%, 0.12%, 0.10% and 0.08%, respectively.
Drawing under steady state corresponding,40,70,110 10 m/min, drawing speed, hole are A average temperature: 90120150170 degrees. When the drawing speed is lower than 80 m/min, the diameter ratio increases faster with the increase of speed. When the drawing speed exceeds 80 m/min, the diameter increases slowly as the speed increases. When the drawing speed is 10 m/min, diameter enlargement ratio closer to 0%, when the work is half cone Angle of 10 degrees, the diameter increased more than 0.1%.
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December 11, 2018
Application of nozzle spray system technology in metallurgical gas
Nozzle spray system is usually cooling, cleaning, spraying and special application of four categories, widely used in metallurgical gas systems, mainly gas cooling, dust removal, mixing, pipe compressor impeller equipment cleaning, corrosion prevention equipment. This paper gives a comprehensive introduction, especially the successful application in China, for the reference of relevant personnel.
Nozzle and spray technology
Nozzles are precision perforating parts designed for specific functions. They must be used together with related equipment to form a spray system.
In abnormal situation, blast furnace top gas temperature is high, up to 700 degrees, must undertake rapid cooling. The use of ordinary roar sprinkler can meet the protection of roof equipment; But easy to cause cloth bag adhesion, sometimes forced to release waste gas, both waste and pollution. We successfully use nitrogen atomizing nozzle to solve this contradiction, which can achieve dry cooling, blast furnace gas does not need to be released when pumping water, but can still enter the cloth bag. This system had better be set in furnace top, can have double function. Some blast furnaces are placed in gravity dust removers for the sole purpose of protecting cloth bags. After nitrogen atomization nozzle is adopted, metal tube heat exchanger can be no longer used for switching, reducing maintenance and TRT power generation efficiency.
Use cloth bag dust collector, exit gas temperature of 200 degrees, if you need to enter the gas tank must be cooled to 50 degrees in order to protect the gas tank sealing material. Saturated cooling tower or indirect water cooled heat exchanger is often used for cooling, and there are many problems such as large cooling water volume and scaling of heat exchanger. We have successfully adopted partial evaporation cooling technology of nitrogen atomization nozzle in the gas pipeline, and achieved remarkable results. The actual comparison of a domestic factory is shown in the table below.
In blast furnace smelting, chlorine element also exists in blast furnace gas due to the presence of chlorine element in charge. In dry dust removal, with the decrease of gas temperature, water in the gas will be condensed out, chloride ions will be condensed into acid water, the net gas pipeline, compensator, valve and other equipment has a serious threat: some plant system operating time is not long on the pipeline corrosion leakage; The cost of anti-corrosion pipeline is very high. Also corrosion after the step of the valve, stainless steel compensator, pipe blowout plate (aluminum plate) and other equipment; Scale is formed on the pipe, after scaling falls off, block pipe and brick of hot blast furnace grid again, because this must take measure to remove chloride ion. Dechlorination ion commonly used dilution method, that is, a large amount of water to the gas, the use of water absorption chloride ion, reduce the corrosion of equipment. Spray water cycle use a certain concentration after replacement. This method is simple, reliable, equipment investment and operating costs, maintenance volume is high; In particular, it can offset the effect of dry dust removal to improve power generation and water saving. We have designed the method of spraying alkali solution to remove chloride ions, that is, spraying alkali solution with nitrogen atomization gun to achieve evaporation cooling, which plays the role of cooling and removing chloride ions at the same time. Alkaline wastewater can also be used to treat waste with waste and reduce equipment investment and operating costs.
We still have a considerable part, especially large blast furnaces are still using two wen, or steam jet tower wet dust removal, large amount of water and water treatment, high system resistance caused by energy and operating costs and waste. By adopting our semi-dry cooling technology of partial evaporation and assisting in the improvement of nozzle type, layout and water supply system, 30-50% water volume can be reduced, nozzle blockage can be completely solved and system resistance can be reduced. The main technical measure is to use the double outlet nozzle of up and down spray; Large orifice carbide nozzle is adopted; Small circulation water supply in series is adopted.
For more details, please visit website at wococarbide.com
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December 04, 2018
What are the compositional application of cobalt based alloy powder Stellite
Co-Cr-Mo-Ni-Fe alloy, with good high temperature strength, thermal stability, resistance to various forms of wear;
Co-Cr-W-C alloy, high hardness, good red hardness, and erosion resistance; The performance of Co-Cr-Al-Y is similar to that of Ni-Cr-Al-Y alloy, but the temperature is higher.
General cobalt-based super alloy lacks a coherent strengthening phase, while in low temperature strength (only 50-75% of nickel base alloy), but in the higher than 980 degrees when has high strength, good thermal fatigue, thermal corrosion and abrasion resistance, and good weldability. It is suitable for making guide vane and nozzle guide vane of aviation jet engine, industrial gas turbine, naval gas turbine and diesel nozzle.
Carbide strengthening phase. The main carbides in cobalt base superalloy are MC, M23C6 and M6C in casting cobalt base alloy. In some alloys, the fine M23C6 can form eutectic with gamma. MC carbide particles are too large to have a significant effect on dislocation directly, so the strengthening effect on the alloy is not obvious, and the fine dispersed carbide has a good strengthening effect. Carbides (mainly M23C6) located at the grain boundary can prevent grain boundary slip, thus improving the lasting strength. The microstructure of cobalt-based high-temperature alloy ha-31 (x-40) is dispersed and the strengthening phase is (CoCrW)6 c-type carbides.
Topologically dense arrangements such as the sigma phase and Laves, which occur in some cobalt-based alloys, are harmful and cause brittle alloys. Cobalt-based alloys are less likely to be strengthened by intermetallic compounds because Co3 (Ti, Al) and Co3Ta are not stable at high temperatures, but cobalt-based alloys strengthened by intermetallic compounds have also been developed in recent years.
The thermal stability of carbide in cobalt base alloy is better. Temperature rise, carbide agglomeration grow up faster than nickel-based alloy phase grew up in both slower, back in the temperature of the substrate is higher (up to 1100 degrees), so when temperature rises, decreasing the strength of the cobalt base alloy is generally slow.
Cobalt base alloy powder has good resistance to corrosion performance, it is generally believed that the cobalt base alloy is better than that of nickel base alloy, in this respect is cobalt sulfides melting point (such as Co - Co4S3 eutectic, 877 degrees) than nickel sulfide melting point (645 degrees) such as Ni - Ni3S2 eutectic is high, and the diffusion rate of sulfur in cobalt nickel in the middle and lower than. Moreover, since most cobalt-based alloys contain more chromium than nickel-based alloys, alkali metal sulfates (such as Cr2O3 protective layer corroded by Na2SO4) can be formed on the surface of the alloys. However, the oxidation resistance of cobalt-based alloys is usually much lower than that of nickel-based alloys. Early cobalt-based alloys were produced by non-vacuum smelting and casting processes. Later developed alloys, such as mar-m509 alloy, because there are more active elements zirconium, boron, etc., with vacuum smelting and vacuum casting production.
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