Doped Tungsten Production Processes
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- Category: Tungsten Information
- Published on Tuesday, 08 October 2013 14:39
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Carolina (T.Millner) in 1931 will this improvement does not sag effect is known as "GK effect ." Then mixed tungsten -doped tungsten production process lengthy production processes , including tungsten smelting, processing of powder metallurgy and plastic preform several major phases . Preparation of tungsten billet billet production of tungsten used usually prepared by powder metallurgy , which includes the preparation of tungsten oxide , doped tungsten powder preparation , pickling, and pressure- sintering process . Preparation of tungsten oxide doped tungsten production is usually chosen by Jones Lang tungstate (APT) as raw materials . Preparation paratungstic from tungsten acid Holderness addition to traditional classical technique , but in the 1950s the international community to carry out extraction and ion exchange method of research, China in the 1970s also used these processes , thereby simplifying the process, improved recovery of tungsten . Industrial preparation of tungsten oxide in two ways :
(1) At a temperature of 500 to 800 ℃ calcined paratungstic acid obtained by the yellow tungsten trioxide ;
( 2 ) Temperature at 400 to 600C in a reducing gas atmosphere at reduced paratungstic acid blue tungsten oxide .
Blue tungsten oxide there is no fixed formula and uniform chemical composition , the main phases money tungsten bronze (ATB) and tungsten oxide . Followed tungsten trioxide , in a reducing atmosphere at a higher temperature will appear in the carbon filament yarn and buttons are spades replaced wire , but thallium low melting point, and thus the operating temperature and luminous efficiency is low . 1903 , according to Jay zafirlukast (A.Just) and Hannah door (F.Hannaman) patents, Hungary for the first time to create a tungsten filament. It is the carbon filament of hydrogen containing tungsten oxyhalide steam heated to high temperatures by the current , the carbon was completely replaced tungsten . Incandescent filament thus obtained contain more or less of carbon , not brittle quite serious , and in the use of the lamp , the filament continued densification , and thus the electrical parameters of the filament will change . In 1904, Jay zafirlukast and Hanna door recognizes the impact of carbon on the brittleness , using carbon- tungsten compound is mixed with a binder , and then extruded into filaments , and then heated in hydrogen reduced to metal . This method is very brittle tungsten obtained , but because of its much better light efficiency , or replacing the carbon filament , hungry for the production of filaments and filament lamps bear . These methods are not prepared thin tungsten wire. To solve this problem , in 1907 , a low nickel content of the tungsten alloy available, it is prepared by machining , but serious brittleness hindered its application .
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How to Detect A Fake Tungsten Gold Bar
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- Category: Tungsten Information
- Published on Tuesday, 08 October 2013 13:48
- Written by Cher
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Detecting a high-quality fake tungsten gold bar would be extremely difficult. It would likely require significant and material alterations to the bar being tested and this would negatively affect the marketability if its hallmark veracity were vindicated.
This is likely a reason why page Page 11 of the GLD prospectus states “Neither the Trustee nor the Custodian independently confirms the fineness of the gold allocated to the Trust in connection with the creation of a Basket.”
Nevertheless, the truly determined and experienced can ferret out whether there is tungsten contained in their gold bars. In fact, some already have found tungsten in bars which purport to be gold and this is how.
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Tungsten Boring Bar and Tungsten Bucking Bar
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- Category: Tungsten Information
- Published on Tuesday, 08 October 2013 10:14
- Written by Cher
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Tungsten heavy metal boring bars are manufactured in sintered or polished alloys of 90%-95% tungsten with a nickel-copper-iron-moly matrix. These alloys are very similar to tungsten-carbides but the chemical composition is developed differently to reduce embrittlement. The high density (twice as heavy as steel) and tensile strength (110 kpsi) of this alloy makes the ideal combination for chatter free tools and supper chatter free tools. Heavy metal boring bars greatly enhance boring application by absorbing vibration and drastically reduce chatter, enabling to machine deeper bores with greater precision and finish.
Tungsten heavy alloy bucking bars are denser than steel, resulting in a bucking bar of the same weight but half the size. Bucking bars are used in rivet setting to upset the shank of the rivet. Tungsten Heavy Alloy bucking bars reduce the recoil when reflecting the impact back to the rivet shank.
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Why Tungsten Alloy is Used as Gold Substitution?
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- Category: Tungsten Information
- Published on Tuesday, 08 October 2013 11:52
- Written by Cher
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In theory, as its density is 19.1g/cm3, which is approximately 70% denser than lead, uranium could be used as material of making fake coin. However, it is weakly radioactive and not as dense as gold, so it does not appear to be a practical method. Then people have discovered that tungsten is environmental-friendly, durable and hardness, the most important is that its density of 19.25g/cm3 is just about the same density as gold (19.3g/cm3), which bears the similar specific gravity. These advantages make tungsten enjoys the superiority to be the best substitute for the costly metal of gold or platinum. It is necessary to tell that alloying gold with tungsten would not work for several reasons but a coin with a tungsten center and gold all around it could not be detected as counterfeit by density measurement alone.
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Bucking Bar Knowledge
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- Category: Tungsten Information
- Published on Tuesday, 08 October 2013 10:08
- Written by Cher
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A bucking bar is used to form the shop head of a rivet. It is held against the shank of a rivet and as the rivet gun bangs on the factory head the bar 'bucks' against the shop head causing the metal to deform. That deformation mushrooms the shank forming the shop head. There are many shapes, sizes, and weights of bucking bars. Many are shaped and sized for special-purpose (generally difficult) situations. Pictured is a typical set of bucking bars.
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