Wide Application of Tungsten

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Tungsten in the form of pure metal and tungsten alloy is widely applied in modern technology. Tungsten alloys mainly refer to alloy steel, tungsten carbide based cemented carbide, wear-resistant and heat resisting alloy. Tungsten is mainly used in the following industrial sectors.

 

Tungsten is widely used in the production of special steel in iron and steel industry

 

The most widely adopted 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. High-speed steel is characterized by automatically quenching when the air is achieving high strengthened tempering temperature (700 to 800 degrees Celsius) and the maintenance of high hardness and wear resistance at the temperature of 600 to 650 degrees Celsius. Tungsten steel of alloy tool steel usually contains 0.8% to 1.2% of tungsten, while chromium tungsten silicon steel containing 2% to 2.7% of tungsten, chromium tungsten steel containing 2% to 9% of tungsten and chromium tungsten manganese steel containing 0.5% to 1.6% of tungsten. Steel containing tungsten is used in the manufacture of various tools including drills, milling cutters, drawing dies, convex molds and concave molds, air support tools and other metal parts. Tungsten magnet steel is a kind of permanent magnet steel containing 5.2% to 6.2% of tungsten, 0.68% to 0.78% of carbon and 0.3% to 0.5% of chromium. Tungsten-cobalt magnet steel is a kind of cobalt hard magnetic material which contains 11.5% to 14.5% of tungsten, 5.5% to 6.5% of molybdenum and 11.5% to 12.5% of cobalt. They both are expected to be with high magnetization intensity and coercive force.

 

Tungsten carbide based cemented alloy

 

Tungsten carbide is characterized by high hardness, wear resistance and infusibility. These alloys contain 85% to 95% of tungsten carbide and 5% to 14% of cobalt, in which cobalt works as a binder metal to endow the alloy with the necessary strength. Certain alloys used for steel production also contain titanium, tantalum and niobium carbides. All these alloys are manufactured through powder metallurgy. When heated to 1000 ~ 1100 degrees centigrade, their high hardness and wear resistance remained unchanged. Carbide cutting tools are far sharper and quicker than even the best steel cutting tools.

 

Heat resistant and wear-resistant alloy

 

Heat resistant and wear-resistant alloy, as the most infusible mental tungsten is the composition of many heat resistant tungsten, such as the alloy composed of 3% to 15% of tungsten, 25% to 35% of chromium, 45% to 65% of cobalt and 0.5% 2.75% of carbon is primarily used in highly wear-resistant metal parts, including the valves of aviation engine, working parts of hot knife for compression moulding, the turbine impeller, excavating equipment, and the coating of plowshares. Alloys made from tungsten and other metals (tantalum, niobium, molybdenum and rhenium) are utilized as heat resistant materials in aviation and rocket technology, and other sectors that require high heat intensity on those machine parts, engines and some instruments.

 

Contact materials and heavy density alloy

 

Contact materials, heavy gravity alloys and tungsten-copper alloy and tungsten-silver alloy produced by powder metallurgy have combined the excellent electrical conductivity and thermal conductivity of copper and silver and the wear resistance. Therefore, it becomes a very effective contact material in the manufacture of knife switch, circuit breakers, spot-welding electrodes and other working parts.

 

Electric vacuum lighting materials

 

Tungsten in the form of tungsten filament, tungsten bands and various forging components is widely utilized in the production of electronic valve and radio electronics. Tungsten is one of the best materials for incandescent filaments and spiral filaments. The high working temperature (2200 to 2500 degrees centigrade) guarantees the high luminous efficiency, while the rather slow evaporation rate ensures the filaments last longer. Tungsten filament can be applied in direct-heated cathode and grid of electronic oscillator, cathodes of high-voltage rectifiers and cathode heaters in various electronic instruments. Besides that, it also can be used in the anticathodes and cathodes of X-ray tubes and gas discharge tubes, as well as the contacts of radio equipment and atomic hydrogen welding torch electrodes. Tungsten filaments and tungsten bars, acting as the heater of the high temperature furnace (up to 3000 degrees Centigrade), work in a hydrogen atmosphere, an inert atmosphere or in vacuum.