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Tungsten Alloy And Dart Stem

Details: Category: Tungsten Information; Published on Friday, 15 March 2013 09:40

The most important part of a dart is the stem, it’s where fingers hold on. The change of stems’ weight will change the shape of darts. Nowadays standard dart stem is made from tungsten alloy and this kind of dart is getting more and more popular all over the world.

There are several kinds of tungsten alloy dart stems including tungsten-nickel-copper stem, tungsten-nickel-copper-iron stem etc. If customers need special darts, they will be customized. Since there are still some barriers in manufacturing skills, tungsten dart stems with purity of 100% can not be made yet. What people can buy in the market are almost tungsten alloy stem, among which tungsten-nickel-iron alloy is the most common one.

Tungsten is a kind of material with high density and endurance. Tungsten alloy dart has small diameter compared with dart made of other materials at the same weight. For dart fans, small-size stem is very important, for it’s more comfortable to hold with fingers. The advent of tungsten alloy darts has contributed a lot to dart sports, as it has greatly improve the average scores in games.

There are some tips for dart fans:

1. When you buy a new set of darts you may notice the percentage of tungsten in the package, say, “tungsten purity 80%”, that means 80% of the material in the stem is tungsten, and the higher the purity the thinner the stem is and, of course, the more expensive the darts are. For ordinary fans 80% is good enough.

2. Remember: the only advantage of a high-purity tungsten alloy dart is that it is thinner, it does not mean it’s of high quality or fine workmanship.

3. Some people are allergic to nickel, and nickel happens to be an element of some darts stem, if those people really want to play dart, they’d better chose a substitute, like tungsten -copper darts.

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Key Characteristics of CVD Tungsten Carbide Coatings

Details: Category: Tungsten Information; Published on Thursday, 14 March 2013 14:26

The key characteristics of CVD tungsten carbide coatings are as follows:

1、Outstanding chemical and corrosion resistance
2、Free from through porosity, thus effectively protecting mild steel substrate from corrosive media without sealing the coating
3、Superior resistance to sulfide stress cracking
4、Provides effective protection against mineral acids such as sulfuric acid and hydrochloric acid
5、Resists Aqua Regia at room temperature
6、Superior wear resistance; Wear rate of CVD tungsten carbide coatings is four fold lower when compared to thermal spray WC, 12 fold lower than hard chrome, and 40 fold lower when compared to abrasion resistant steel AR-500
7、Demonstrates better erosion rate when compared to chrome carbide weld overlay, hard chrome, white iron, cemented carbide, and various other hard materials
8、Better fatigue resistance and toughness
9、Superior resistance to impact and deformations
10、Deposition from the gas phase enables coating of internal surfaces and intricate shapes.

A micro-photograph of a cross-section of 50-microns thick CVD Tungsten Carbide coating type T on thread. The uniform coating follows the substrate; even slight imperfections are accurately followed (magnify. 20X).

Comparison results of ASTM G65 tests of CVD tungsten carbide coating abrasion resistance against other hard materials is depicted.

Results of ASTM G65 tests of CVD Tungsten Carbide coating abrasion resistance as compared to the results for other hard materials.

Corrosion resistance of CVD tungsten carbide coatings is demonstrated.

Samples of three different coatings after salt spray corrosion tests: left - HVOF after 480 hours; centre – Hard Chrome after 288 hours; right – CVD coating type T after 480 hours.
Applications of CVD Tungsten Carbide Coatings

CVD tungsten carbide coating is suitable for applications with many different components operating in extreme erosive and abrasive atmospheres, such as critical components of metal seated ball valves, downhole tools, and pumps handling abrasive fluids.

Ball valves coated with CVD tungsten carbide coating, demonstrate increased valve life thanks to the coating as it make them scratch-proof and able to resist erosion and abrasion.

Ball valves coated with CVD Tungsten Carbide coating.

CVD tungsten carbide coating extends the life and reduces downtime costs of downhole tools such as grippers for down-hole tractors, high loading bearings pins, and mud-driven hydraulic parts for directional drilling tools.

CVD tungsten carbide coating type T is applied on outside piston and inside cylinder of a positive displacement pump transporting abrasive viscous fluids at pressures as high as 2800 psi to reduce wear, thus increasing pump life threefold.

CVD tungsten carbide coating is an ideal alternative to phase-out hard chrome plating because it involves carcinogenic hexavalent chromium, thus causing negative impact on environment, health and safety.
Conclusion

With these qualities, CVD tungsten carbide coating becomes an ideal solution to improve the performance and life of critical components of valves, downhole tools, and pumps operating in power generation, cryogenic equipment, refineries, food manufacturing, and oil and gas facilities.
About Hardide Coatings

Hardide Coatings produce a range of advanced surface engineering coatings that protect the internal and external surfaces of components from wear, erosion and acidic corrosion.

The coatings are proven to extend the life of metal parts operating in harsh environments for a variety of industries including oil & gas, valves, pumps, aerospace and advanced engineering.

Wear and Corrosion Protection Using CVD Tungsten Carbide Coatings

Details: Category: Tungsten Information; Published on Thursday, 14 March 2013 14:16

The life of critical components and tools can be increased by many different hard coatings and surface treatments such as boronizing, nitriding, hard chrome plating, plasma and thermal spray coatings, physical vapor deposition (PVD) and chemical vapor deposition (CVD) coatings. However, each technique has its own disadvantages. This article discusses the innovative CVD tungsten carbide/tungsten coating named as Hardide, Which exhibits exotic properties.
Types of CVD Tungsten Carbide/Tungsten Coatings

CVD tungsten carbide coatings are different from other tungsten carbide coatings as they do not use cobalt or nickel metal matrix binder. CVD tungsten carbide/tungsten Coatings are available in four different types.

The hardest coating type H comprises pure tungsten carbides, thus demonstrating high hardness but with only 'satisfactory' toughness. The multi-layer coating type M features layers of different hardness. It is possible to modify the overall coating characteristics by changing the ratio between the thickness and properties of individual layer based on specific application requirements. CVD tungsten carbide coating type T is the most widely used coating.
Nano-Structure of CVD Tungsten Carbide Coating Type T

Coating type T is a sophisticated nano-structured material comprising a metallic tungsten matrix with dispersed tungsten carbide nano-particles with a typical size range of 1-10 nm.

High resolution electron microscopy image of precipitate in CVD coating type T deposited on Cu substrate. The atomic distances (1.49 and 1.76 Å) directly taken from the precipitate region are matched best to the lattice constants of W2C (110- 1.49 Å and 102 - 1.74 Å).

The coating type T demonstrates abrasion resistance up to twelevefold higher than that of hard chrome and improved hardness of more than 1100 Hv. The coating can be formed on titanium, low alloy and some tool steels, stainless steel, and Ni-, Co- and Cu-based alloys. This nano-structured material shown unprecedented impact resistance, crack resistance and toughness by tolerating 3000 microstrain deformations without any deterioration.
CVD Tungsten Carbide Coating Porosity

CVD tungsten carbide coating is devoid of through porosity from a thickness of below 1 µm thanks to its deposition mechanism. The crystallization of the coating takes place from the gas-phase atom-by-atom, and the defects and micro-pores in the coating are filled by the highly mobile reaction products as the coating grows.

SEM image of a cross-section of CVD coating layer on cemented carbide substrate. The coating as deposited has exceptionally low porosity and it can isolate substrate material against attacks of aggressive media, such as acids.

Tungsten Carbide Moulds Have Broad Prospect in the Market

Details: Category: Tungsten Information; Published on Thursday, 14 March 2013 11:22

Tungsten carbide is a main raw material in the making of tungsten carbide alloy, it is also know as Wolfram Carbide. Tungsten carbide has metal gloss and has hardness similar to adamas, it is also a good conductor of electric current, its melting point is 2870℃ and boiling point 6000℃，relative density is 15.63 （at18℃）. This kind of material does not dissolve in water, hydrochloric acid and vitriol.

Owing to these physical properties, tungsten can be used in making, attrition-resisting, strike-resisting and corrosion-resisting moulds, the use of tungsten in moulds can extent the their service lives. Thus will effectively save the cost of moulds in production and improve economic performance. This sort of mould can be used in our special processing, too. It is known that China is the largest manufacturing country in the world, the application of mould is wide in many areas. Tungsten carbide moulds will undoubtedly receive warm welcome from a great number of enterprises. Experts therefore expect that tungsten carbide moulds will have board prospects in the market.

The History of Tungsten Alloy Shell

Details: Category: Tungsten Information; Published on Tuesday, 12 March 2013 10:14

It was uncommon to see Tungsten Alloy Shells filling with explosive until the middle of the 16^th century. In the early days, it was common to find duds in carronades, as the fuse tubes in the carronades are made of synthetic powder which burned slow and thus caused instability when igniting the black power.

It was not until 1823, cannons which could be filled with explosive shells were finally invented by A French General named Henri-Joseph Paixhans. In the 19^th century, most of shells that can be seen are made from cast iron, tungsten alloy shells were used in piercing amour initially, as cast iron shells were incapable of bearing the knockings of new type of powder.

In World WarⅠ, 70% of injuring of infantries in battle fields were caused by the shell fragments from tungsten alloy shells.

Applications of Tungsten

Details: Category: Tungsten Information; Published on Monday, 11 March 2013 14:45

Tungsten is a kind of non-ferrous metal which is of strategic value . Tungsten used to be named “ heavy stone” in ancient times. In 1781 Swedish chemist Carl William discovered scheelite from which a new element was extracted – tungstic acid, in 1783 Spanish Drepoyer extracted tungstic acid from wolframite . The content of tungsten is about 0.001% in earth crust and there are about 20 sorts of discovered ores contain tungsten.

Nowadays about 50% exploited tungsten ores are used in the smelting of high-quality steel, 35% of them are used in producing harden steel and 5% of them are used in other area. Tungsten can be applied in many areas like gunsmithing, and the making of jet nozzles of rockets , cutting tools, drills, super-hard models and so on. Tungsten has wide applications, involves mining, metallurgy, building, machinery, traffic, electron industry, chemical industry, light industry , textile , military , aero space and technology. And the most common – tungsten wire in the incandescence bulb.

Domestic Tungsten Ore Quotes Stabilization

Details: Category: Tungsten Information; Published on Monday, 11 March 2013 14:10

Stable the domestic tungsten ore prices, the shipping industry will be raised to 1.6 yuan / kWh, and a slight improvement in market demand for some high-priced, sodium tungstate, scrap tungsten steel prices continue to explore domestic blade even reached 175 yuan / kg.The tungsten market sentiment dropped slightly, the reproduction manufacturers there to see, in the case of the lack of a large number of transactions supported mainly stable short-term tungsten Department mainstream.

Tungsten in the Bulb

Details: Category: Tungsten Information; Published on Monday, 11 March 2013 11:49

Before the advent of electric light, people used candles, kerosene lamps, and gas lamp as illumination tools. Those fuel lights release pungent smell when burning while emitting dark smoke, what’s more, they require replenish fuel from time to time, scrubbing lampshade is also a hard work. What makes them worse is that they always catched fire thus caused great damage. Since the invention of electric, people had been seeking for a new source of light.

In the 19^th century, an English chemist invented the first electric arc lighting in the world by combining 2000 batteries with two carbon rods. Since the light generated from this kind of illumination tool was too bright to be put in the house, it could only be set in the streets or squares. Scientists did not stop seeking for a new light which would cost less money and last much longer.

The next illumination tool that came into view was incandescent lamp, it’s a kind of lamp which uses electricity to heat its filament into the so-called “incandescent state”, and the filament will be lighted to provide light. Incandescence is very high temperature that means the filament should be able to endure super-high temperature. But high melting-point filament had been an elusive material.

The great Inventor Edison began his seeking for the high-melting point filament in 1878, he used about 1600 kinds of material in his experiments, even used precious metals like platinum, barium and titanium. Those experiments, however, were either unsatisfactory or cost too much money.

In December 21th, 1879, through incessant experiments he lighted the first lighting bulb of practical value for the world. He finally proved that tungsten was the best material for filament.

Tungsten is of high resistivity-- 5.3*10^-8, it has a high melting point over 3000 degree, its intensity is high and what’s more, tungsten is relatively cheep compared with other materials. The use of tungsten has made electric illuminations enter into millions of ordinary houses, and change the world ever since.

New Types of Batteries Will Increase Energy Storage

Details: Category: Tungsten Information; Published on Thursday, 07 March 2013 12:04

Industrial chemists at Argonne National Laboratory in Lemont, near Chicago, wave a tube of white powder in the air emphatically. A mere pinch of the contents is sufficient for analytical colleagues to work out if it has the potential to be the next whizzy material in battery research.

Batteries are a hugely important technology. Modern life would be impossible without them. But many engineers find them disappointing and feel that they could be better still. Produce the right battery at the right price, these engineers think, and you could make the internal-combustion engine redundant and usher in a world in which free fuel, in the form of wind and solar energy, was the norm. That really would be a revolution.

It is, however, a revolution that people have been awaiting a long time. And the longer they wait, the more the doubters wonder if it will ever happen. The Joint Centre for Energy Storage Research (JCESR), at which Dr Pupek and his colleagues work, hopes to prove the doubters wrong. It has drawn together the best brains in energy research from America’s national laboratories and universities, along with a group of interested companies. It has money, too. It has just received a grant of $120m from the country’s Department of Energy. The aim, snappily expressed, is to make batteries five times more powerful and five times cheaper in five years.

Most batteries, from the ancient, lumbering lead-acid monsters used to start cars, to the sleek, tiny lithium cells that power everything from e-book readers to watches, have three essential components: two electrodes (an anode and a cathode) and a medium called an electrolyte that allows positively charged ions to move between the electrodes, balancing the flow of negatively charged electrons that form the battery’s useful current. The skill of creating new types of battery is to tinker with the materials of these three components in ways that make things better and cheaper. The white powders are among those materials.

New battery will be to beat the most successful electricity-storage device to emerge over the past 20 years: the lithium-ion battery. Such batteries are now ubiquitous. Most famously, they power many of the electric and hybrid-electric cars that are starting to appear on the roads. More infamously, they have a tendency to overheat and burn. Two recent fires on board Boeing’s new 787 Dreamliners may have been caused by such batteries or their control systems. Improving on lithium-ion would be a feather in the cap of any laboratory.

George Crabtree, JCESR’s newly appointed director, thinks such improvements will be needed soon. He reckons that most of the gains in performance to be had from lithium-ion batteries have already been achieved, making the batteries ripe for replacement. Jeff Chamberlain, his deputy, is more bullish about the existing technology. He says it may still be possible to double the amount of energy a lithium-ion battery of given weight can store, and also reduce its cost by 30-40%.

This illustrates the uncertainty about whether lithium-ion technology, if pushed to its limits, can make electric vehicles truly competitive with those run by internal-combustion engines, let alone better. McKinsey, a business consultancy, reckons that lithium-ion batteries might be competitive by 2020 but, there is still a lot of work to do. Moreover, pretenders to lithium-ion’s throne are already emerging.

The leader is probably the lithium-air battery, in which metallic lithium is oxidised at the anode and reduced at the cathode. In essence, it uses atmospheric oxygen as the electrolyte. This reduces its weight and means its energy density is theoretically enormous. Bringing that ratio down would make electric vehicles more attractive.

The lithium-air approach has consequently generated a lot of hype. It has problems, though, which will take years of research to resolve. Lithium-air batteries are hard to recharge and extremely temperamental. The chemical reaction which powers them is not far removed from spontaneous combustion. Lithium-air batteries are thus highly inflammable and require heavy safety systems to stop them catching fire.

Luckily, the researchers at JCESR have other irons in the fire. One is the multivalent-ion battery. A lithium atom has but a single electron available for chemical reactions. A magnesium atom, by contrast, has two such valence electrons, and an aluminium atom three.

Theoretically, says Dr Chamberlain, this means it might be possible get two or three times as much energy out of a magnesium or aluminium battery. Though these metals are not as light as lithium, their extra valence electrons increase the amount of energy they can store, thus pushing them forward in the competition with petrol. They are also cheaper than lithium and safer. Their ions, however, are harder to move around inside a battery, which is why they have not been used much in the past, and this is where new materials will need to be sought out.

The second transformation, besides electric cars, that better batteries might bring about is what is known as grid-scale storage. If this could be done cheaply enough it would revolutionise the economics of wind and solar energy by making the main problem with such sources—that the sun does not always shine and the wind does not always blow—irrelevant. To this end, Argonne’s researchers are working on what are known as flow batteries

In a conventional battery the electrolyte is contained within the cell and serves to transport ions between the electrodes. The battery’s charge is held as chemical potential energy in those electrodes. In a flow battery the charge is held in the electrolyte itself, which is stored in a tank and then pumped through the cell to the place where the electrochemical reactions occur.

Unlike batteries based on cells, flow batteries can be made very large indeed, so they can store vast amounts of energy. Hence the idea of using them to collect surplus power from wind turbines and solar panels and squirrel it away for use later. But their water-based electrolytes limit their potential, because of water’s tendency to decompose by electrolysis. That restricts the voltage at which they can operate. Replacing their aqueous electrolytes with organic ones would overcome this limitation, and Argonne’s researchers are endeavouring to do so.

A battery-driven world, then, would electrify parts of the economy, such as transport, that have been recalcitrant, and would encourage the shift from costly (and polluting) fossil fuels to “fuels” such as sunlight that cost nothing.

The Shanghai Period of Rebound in Metal today

Details: Category: Tungsten Information; Published on Tuesday, 05 March 2013 18:34

Shanghai period metal today as scheduled rebound, the stock market also rose sharply, recycling yesterday's decline; headed to Shanghai copper base metals rebound force is not very strong, so rely on such a rebound to reverse the pattern is not very realistic, so the top of the 10thaverage material there is still a lot of pressure, but the trend of the outer disk metal stronger, so the short-term Shanghai metal or into low sideways pattern, however, which makes the pattern of the previous decline eased, despite the rebound relatively weak, but can continuea long time, can also play a role in market sentiment conversion; overall the Shanghai period of the metal is Change conversion stage, the material will be time-consuming. The rebound limited the Shanghai period lead today, an increase of more than 60 tons of lead warehouse receipts, the lead spot short-term pressure exists on the whole, but it is difficult up rather than down.

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