2015年6月1日星期一

Tungsten Special Properties and Wide Applications



Tungsten is a type of silvery metal with the appearance similar to steel. It has high melting point, low vapor pressure and small vaporization velocity. Also, high hardness, excellent high-temperature strength and property of electric conduction and thermal transfer are its physical properties. In normal temperature, Tungsten Chemical Properties are stable. It doesnt react with air and water and is erosion resistant so that it doesnt solve in hydrochloric acid, sulfuric acid, nitric acid and aqueous alkali, but only in mixture of chloroazotic acid, nitric acid and hydrofluoric acid. However, in high temperature, it chemically combines with chlorine, bromine, iodine, nitrogen and sulfur but not hydrogen. 

On account of special properties of tungsten, it gets much favor by Tungsten Producers, taking the example of China Tungsten Online. As well, Tungsten Market is much wide since it has wide applications which cover mineral, metallurgy, machine, building, transportation, electronic, chemical industry, light industry, textile, military, aerospace, science and various industrial fields. Nowadays, tungsten is widely applied in modern technology by the state of pure metal and alloy system. Alloy system primary refers to alloy steel, cemented carbide based on tungsten carbide, abrasion resistant alloy and great thermal alloy. Below, lets come to its application in following industrial fields.

Cemented carbide based on tungsten carbide

Carbide of tungsten has high hardness, erosion resistance and infusibility due to Tungsten Metal Properties and mechanical properties of tungsten. It contains tungsten carbide and a little quantity of cobalt. Cobalt acts as metal of bonding agent to offer alloy necessary intensity. Those tungsten carbide used in finished steel still contain titanium, tantalum and niobic carbide. All these alloys are manufactured by power metallurgic method. Cemented carbide cutter has a cutting speed far quicker than that of good chisel tool steel cutter. Therefore, cemented carbide is mainly applied for cutting tools, mine tools and wire-drawing dies.

Great strength and abrasion resistant alloy

As the most infusible metal, tungsten is the component of many high strength alloys such as alloys composed of tungsten, chromium, cobalt and carbon which are mainly used in surface coating on strongly erosion resistant parts like valve of aircraft engine, working parts of die thermal cutter, impeller of turbine motor, digging equipment and plowshare. In aviation, rocket technology and other departments that have requirements on high thermal strength on machine parts, engine and some apparatus, tungsten and other fusible metal like alloy of tantalum, niobium, molybdenum and rhenium can be used as high strength material. 

Contact material and high proportion alloy

Tungsten-copper alloy and tungsten-silver alloy manufactured by powder metallurgy method has excellent electrical conductivity and thermal conductivity of both copper and silver as well as tungsten abrasion resistance. Thus, tungsten, by virtue of tungsten material properties, becomes the effective contact material in manufacturing working parts like knife switch, disconnector and spot-welding electrode. As for those high proportion alloys of tungsten, nickel and copper and alloys replacing copper with ion are used to manufacture gyroscope rotor, plane, balance weight of control rudder, radioactive shield of radio isotope and charging basket.

Electric vacuum illuminating material

Tungsten is applied in electron tube production, radio electronics and X-ray technology. Tungsten can be applied to produce the anticathode and cathode of X-ray tube and gas discharge tube as well as contactor of wireless apparatus and electrode of atom hydrogen welding gun. At meanwhile, tungsten is the best material for glower and taenidium on account of Tungsten Filament Properties. In addition, tungsten is applied to manufacture thermionic cathode and grid electrode of electronic oscillation tube, cathode of high pressure rectifier and separately heated cathode heater in various electronic instruments, which can work in hydrogen, inert gases or vacuum.

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