In Tungsten carbide alloy areas, the tungsten mainly applies on the form of WC. The main method of production of WC is the carbonization of metal tungsten powder, so the quality of the metal tungsten powder has a larger impact on the quality of Tungsten carbide alloy products. Quality Tungsten carbide alloy should first be prepared to comply with certain requirements of the tungsten powder.

The request of Tungsten carbide alloy field for raw materials tungsten powders are mainly chemical purity, physical properties and process performance. Physical properties including particle size, grain shape, particle size distribution and particle aggregation state, these tend to be different due to specific users different; process performance including mobile, pressing and sintering performance,  therefore in the metallurgical process, certain measures should be taken to improve the performance of the tungsten powder.

The mainly application of tungsten is in the Tungsten carbide alloy field. More than about 50% of the tungsten is used for the manufacture of tungsten carbide based cemented carbide. Tungsten carbide alloy has a number of excellent properties, mainly: a high hardness and wear resistance, particularly the high-temperature hardness, the hardness of Tungsten carbide alloy at 600℃ exceeds the high-speed steel at room temperature, the hardness of Tungsten carbide alloy at 1000℃ exceeds the carbon steel at room temperature; high elastic modulus, usually (40 to 70) × 104MPa. Thus Tungsten carbide alloy at room temperature has good rigidity, no significant plastic deformation; high compressive strength; small expansion coefficient, but its thermal conductivity and electrical conductivity similar to the iron and its alloys; chemical stability, acid-resistant alkali-resistant, at 600 ~ 800℃ has no significant oxidation; and good thermal stability. As a result of the above series of excellent performance, Tungsten carbide alloy occupy an important position in modern tools and materials, wear-resistant materials, high temperature and corrosion-resistant materials, in particular, showed great superiority in the machining industry. Compared with alloy steel tools, the main advantages of Tungsten carbide alloy are as follows’:

(1) Metal cutting speed can increase the number of times, greatly improving the productivity of labor;

(2) Manufactures size accuracy is improved; the surface roughness is reduced;

(3) The machinable of materials which are difficult to process with high-speed steel, such as heat-resistant alloys, titanium alloy, special hard cast iron and so on.

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In iron and steel industry, tungsten mainly joins as Ferrotungsten form. These processes put tungsten concentrates, scrap iron and other things together in an electric arc furnace, and get ferrotungsten after reduction smelting, and then join ferrotungsten into steelmaking process. In some cases, Tungsten powder can also be processed into tungsten bar, added in the form of tungsten bar in the steelmaking process. Recent successful studies of scheelite direct steelmaking processes, add scheelite directly in the steelmaking process, then use ferro-silicon or carbon as reducing agent, tungsten is reduced into the steel.he tungsten adds into steel enables the steel grain refinement, to improve its high-temperature hardness, wear resistance and impact strength.

Tungsten steel is mainly used for cutting steel and die steel, and its application in high-speed cutting steel is more than a century of history. The widely used high-speed steel contains 9% to 24% of tungsten, 3.8% to 4.6% of chromium, 1% to 5% of vanadium, 4% to 7% of cobalt and 0.7% to 1.5% of carbon. The characteristics of high-speed steel is high reinforcing tempering temperature (700 to 800℃), it can automatically quenching and secondary hardening in the air, so it can maintain a high hardness and wear resistance up to 600 ~ 650 ℃. In the alloy tool steel group, tungsten steel containing 0.8% to 1.2% tungsten; chromium tungsten silicon steel containing from 2% to 2.7% tungsten; containing 2% to 9% of the tungsten in the chromium-tungsten steel; chromium tungsten manganese steel containing 0.5% ~ 1.6% tungsten. Tungsten steel is used to manufacture a variety of tools, such as drills, mills, wire drawing dies, female mold and male mold, pneumatic tools parts and so on. Tungsten magnets is a permanent magnet steel containing 5.2% to 6.2% tungsten, 0.68% to 0.78% carbon, and 0.3% to 0.5% chromium; tungsten-cobalt magnets is a hard magnetic material containing 11.5% to 14.5% tungsten, 5.5% to 6.5 % of molybdenum, 11.5% to 12.5% of the cobalt, they have high magnetization and the coercive force, they are of important magnetic materials.

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The deer season for 2012-13 is history, but that doesn’t mean that hunting season is over. Small game, like rabbits and squirrels, may still be hunted as well as grouse. But perhaps the most exciting hunting prospects are for geese.

Goose hunting can be fun and productive, and you do both the birds themselves and the landowners a favor by shooting a few. In recent years, the game officials have practically begged hunters to help keep the flocks under control with liberal limits and extended seasons. Yet, very few hunters take advantage.

One stumbling block is getting legal in the license department, which involves a trip to the long lines at the United States Postal Service to obtain a duck stamp. A hunter must also have a valid state hunting license and a Virginia Migratory Waterfowl Conservation Stamp. You also have to use a non-toxic shot such as steel, bismuth, tungsten or an approved allow – definitely not lead.

Make a note that your gun must be plugged to accept not more than three shells. In recent years, game laws allowed more than three shells for the deer season, and many shotguns used for deer are also used for geese.

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As companies spent the recent year-end holidays closing their fiscal books and creating program budgets for new products and services into 2013, a small and seemingly obscure clause in one of the widest reaching financial reform acts in modern history has added concern and challenge to product manufacturers across industry segments.

The Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 contains a small but very important section addressing so-called “conflict minerals” – referred to as 3TGs (tin, tantalum, tungsten, and gold) – harvested from the Democratic Republic of Congo and surrounding countries. The people in these areas are experiencing war atrocities, human slavery, and other human rights violations cited by the United Nations.

As such, Section 1502 of the Dodd-Frank Act suggested that this issue requires an aggressive supply chain reporting mandate. The U.S. Securities and Exchange Commission (SEC) made final rulings on this provision in late August 2012 ascribing any publicly traded company and their suppliers to “include a description of the measures it took to exercise due diligence on the conflict minerals’ source and chain of custody” and file a new SEC form SD beginning in 2014 for the 2013 calendar year. The initial reporting period for tracking compliance efforts begins in January, 2013.

Far-reaching Impacts

According to leading industry experts in the field, the effects of the conflict minerals provisions are extensive. “It’s not just whether you are a public company, in which case you for sure must report and show due diligence through your supply chain. Also, private companies and companies that are part of the US company’s supply chains will be affected, as the requirements are cascaded down the value chain. It has been suggested by the SEC that the number of companies that may contain trace elements of conflict minerals could be in excess of 280,000,” notes Thomas Bley, senior project manager for software maker iPoint-systems and participant in a number of industry work groups.

One of the challenges that make conflict mineral compliance to Dodd-Frank so encompassing is the level of trace elements of 3TGs found in most electronics components, used in everything from computers to automobiles to household appliances. It is difficult for one company on its own to trace the flow of materials in raw form back to the component suppliers, however Dodd-Frank requires even deeper due diligence to determine the actual location of the mineral smelter. Some organizations have stated publicly that obtaining declarations of conflict minerals to a level of only 40-60% is sufficient.

“That’s a risky proposition,” suggests Bley. “While there are no penalties for using conflict minerals in company products, the regulations require that a ‘reasonable country of origin inquiry’ is performed. Those companies that lag in this area risk ‘named and shamed’ by the consumer public and nongovernmental organizations (NGOs),” creating a possible impact on brand reputation and sales.

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Tungsten carbide is a tungsten-carbon compound that contains an equal number of carbon and tungsten atoms. It is a fine, gray-black powder that is pressed into various shapes for use in applications. According to "Handbook of Chemical Vapor Deposition," tungsten carbide is prepared by the reaction of carbon with tungsten metal at temperatures between 1,400 Celsius to 2000 Celsius. Tungsten carbide powder comes in many shapes, particle sizes, microstructures and chemical compositions, including fine tungsten monocarbide powder and macrocrystalline tungsten.

Hardfacing
Tungsten carbide powder is commonly used for hardfacing metals. Hardfacing is the process in which a tougher, harder material is applied to a softer base metal. Tungsten carbide improves the wear-resistant properties of a base metal. It is applied to mining equipment parts (shovel teeth, heel plates, bucket wheel excavator teeth, wear parts, crushing hammers, cutter drums and longwall miners), mineral processing equipment (hammers, chutes, pulverizing and grinding parts), earth-moving and construction equipment (grader blades, cutting edges, augers, trencher teeth, ground engaging tools and tunneling equipment), drilling tools, processing equipment and agriculture equipment (subsoilers, discs and injectors).

Diamond Tools
Tungsten carbide powder is used to manufacture tools used in the diamond industry, such as segments, grinding wheels and scape. According to the book "Exploring Advanced Manufacturing Technologies," tungsten carbide diamond cutting tools are made by sintering diamond powder to a tungsten carbide base and then cutting them into various shapes. These shapes are inserted or brazed in tool bodies and then ground to finished shape and sizes. Diamond tools are used to cut hard materials, such as stone, glass and porcelain.

Consumer Goods and Sports
Tungsten carbide is used in common consumer goods, including razor blades. Tungsten carbide powder is used in men's wedding bands to give them a dark hue and to improve their scratch-resistance. Tungsten carbide powder is used to make sporting equipment and devices, such as trekking poles, cross-country skis, bicycle studs and drive tracks for snowmobiles. Hikers and trekkers use tungsten carbide-tipped poles and walking sticks to reduce pressure on leg joints and for balance. They are effective in providing traction on rock surfaces.

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Tungsten inert gas (TIG) welding, also known as gas tungsten arc welding (GTAW), is an arc welding process that uses a tungsten electrode to transmit the electric arc to the work piece. Unlike other arc welding methods, the tungsten electrode does not provide material to the weld, so a separate filler rod is needed for that purpose. Some tungsten electrodes are made with a small amount of thorium, which is a radioactive material and improves the welding qualities of the electrode.

Welding With Tungsten
Tungsten has the highest melting point of all metals, so the electrode material does not melt when exposed to the high temperatures of the arc. Tungsten can be used to weld metals and specific alloys designed to have a high melting point. Even though the tungsten electrode doesn’t melt during the welding process, the electrode can wear or chip over time. The electrode can be reshaped to a conical or rounded shape using a grinder.

Electrodes That Contain Thorium
Thoriated tungsten electrodes are made from tungsten combined with 1 to 2 percent thorium in the form of thorium dioxide. Thoriated tungsten electrodes result in improved welding properties over pure tungsten electrodes. By using thoriated tungsten electrodes, welders find it easier to start the arc and maintain the arc, reduce weld contamination, carry a higher level of current, and achieve a longer electrode life through reduction in wear.

Concerns
Thorium is a radioactive element, so thoriated tungsten electrodes do emit some radioactivity, but the amount is relatively low. Thorium mainly emits alpha particles, which can’t pass through a sheet of paper, but could potentially damage skin tissue with prolonged exposure. Thoriated tungsten electrodes should be stored in a steel container marked with the radiation trefoil as an identifier.

The Natural Council on Radiation Protection and Measurements (NCRP) estimates that the average annual effective dose welders are exposed to when working with thoriated tungsten electrodes regularly, is a maximum of 16 millirem. The amount of background and medical doses incurred by members of the U.S. population each year is about 250 to 1,000+ millirem, so the exposure due to the thoriated tungsten electrodes is small. However, common sense safety precautions should be taken to avoid excessive exposure, including not carrying electrodes close to the body, and wearing standard welding equipment while performing TIG welding. Welders should wear a mask while grinding thoriated tungsten electrodes to avoid breathing in particulates from the grinding process.

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An incredibly strong and dense metal, tungsten can be combined with ceramic to make rings and other fine jewelry. Tungsten ceramic rings are becoming a popular choice for many wedding bands due to their durability and beauty.

Identification
Tungsten is a steel-gray metal. When paired with tungsten, ceramic is often polished black for greater contrast.

Strength
When processed with carbon at high temperatures, tungsten forms tungsten carbide, the hardest metallic substance in the world. Tungsten ceramic rings have unmatched strength.

Benefits
Tungsten ceramic polishes to a mirror-like finish. It's also highly resistant to abrasions and scratches. It would take deliberate scratching from diamonds or corundum to inflict any damage whatsoever.

Considerations
Tungsten ceramic rings, while nearly impervious to scratching, are not indestructible. Tungsten ceramic's hardness makes it slightly more brittle than traditional jewelry metals, meaning it can be crushed under severe stress.

Warning
Once manufactured, tungsten ceramic rings can not be resized due to tungsten's remarkable hardness.

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According to the Centers for Disease Control and Prevention (CDC), tungsten "is a naturally occurring steel-gray to tin-white metal or fine powder that comes from more than 20 different tungsten-bearing minerals." Its atomic number is 74, and its atomic symbol is W. Normally used to toughen steel, the increase of industrial activity in the United States has heightened the chances of people being exposed to tungsten.

Means of Exposure
People can be exposed to tungsten by drinking water, eating food or breathing air that has been contaminated by tungsten. Although tungsten is naturally present in the environment in small amounts as minerals, industrial plants that manufacture tungsten can release large quantities of tungsten into the air.

Entering and Leaving the Body
Tungsten enters the body through eating, drinking, touching or breathing. Scientists are unsure about the metabolism of tungsten in the body, but it does enter the bloodstream and is spread to all parts of the body. Most of the tungsten is quickly processed in the digestive system, leaving your body either through urine or feces.

Health Effects
When exposed to high levels of tungsten, the immediate effects on the body can be irritation of the skin, eyes, throat or nose. Long-term effects can involve a myriad of lung problems, most likely coughing, wheezing and shortness of breath. Many of the long-term effects have been attributed to the use of cobalt in the tungsten-refining and compounding processes. It is important to understand that these side effects are the result of long-term heavy exposure to tungsten, not the minimal exposure to tungsten that most people experience.

Inconclusive Research
Currently, there is not enough scientific research to determine whether tungsten exposure leads to leukemia or other forms of cancer. The general rule of thumb is the more a person is exposed to tungsten, the higher the likelihood of that person experiencing some health effects

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Finding Tungsten
Tungsten is often found in conjunction with other metals such as wolframite (the element in which tungsten was first discovered whose name means "devourer of tin") and scheelite. Around the world, China is the most common place that tungsten is found and mined, though other locales such as Austria, Bolivia and Portugal also have mines that produce respectable amounts of this metal for use in light bulbs, rockets, and in the case of some first world countries, spacecraft.

Refining the Tungsten
Once the ores containing tungsten have been mined from the earth, a process developed by those who discovered tungsten (the Elhuyar brothers Juan and Fausto who were chemists in the late 1700s) is used to purify the metal. The ore that contains the tungsten is crushed, cleaned and then treated with various alkalis so that tungsten trioxide is formed. The tungsten trioxide is then heated using either carbon or hydrogen gas, which then separates the tungsten metal from either the water vapor or the carbon dioxide that forms, depending on which gas was used in the heating and refining process.

The Final Step
Pure tungsten, which is often a whitish or a gray color once it's separated from the ore it was mined in, is in a state referred to as powered tungsten. If necessary, powered tungsten can be used right away without any further modifications. However, if there is no pressing need for the tungsten right then, it will be shaped into bars to be stored or transported. Given that tungsten is a relatively malleable and ductile metal, this process isn't a very difficult one.

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