Tungsten

tungsten is a metal element with the element symbol W. It has high hardness, high melting point, and is not corroded by air at room temperature; it is mainly used to manufacture filaments, high-speed cutting alloy steels, super-hard molds, and also used in optical instruments and chemical instruments. China is the world’s largest tungsten storage country.

Tungsten has an atomic number of 74, a relative atomic mass of 183.85, an atomic radius of 137 picometers, and a density of 19.35 grams per cubic centimeter. It belongs to the VIB group of the sixth period (the second longest period) of the periodic table. Tungsten is mainly a hexavalent cation in nature, and its ionic radius is 0.68×10-10m. Because W6+ has a small ion radius, high electricity price, strong polarization ability, and is easy to form complex anions, tungsten is mainly in the form of complex anions [WO4]2-, which combines with Fe2+, Mn2+, Ca2+ and other cations in the solution to form wolframite or white Tungsten ore deposits. After smelting, tungsten is a silver-white shiny metal with extremely high melting point, high hardness, low vapor pressure, low evaporation rate, and relatively stable chemical properties.

Name	Wolfram,Tungsten	Melting Point	3410±20℃
Boiling Point	5927°C (under a standard atmospheric pressure)	Density	19.35 g/cm³
Element Symbol	W	Atomic Weight	183.84
Element Type	metal	Element Form	Solid state
Discoverer	Carl Wilhelm Scheler	Atomic Number	74
Moh’s Hardness	7.5	Period	The sixth cycle (the second longest cycle)
Distribution In China	Jiangxi, Hunan, Henan	Belonging To Ethnic Group	Group VIB

The Detail Of Tungsten

Metal Type

Non-Ferrous Metals

Tungsten is a non-ferrous metal. Generally, people divide metals into two categories based on their color and properties: ferrous metals and non-ferrous metals. Ferrous metals mainly refer to iron, manganese, chromium and their alloys, such as steel, pig iron, ferroalloys, and cast iron. Metals other than ferrous metals are called non-ferrous metals. Tungsten belongs to the category of non-ferrous metals. The strength and hardness of non-ferrous alloys are generally higher than that of pure metals, the resistance is larger than that of pure metals, the temperature coefficient of resistance is small, and it has good comprehensive mechanical properties. Therefore, as a non-ferrous metal, tungsten has very high strength and hardness. Due to this characteristic, tungsten carbide with high hardness and strong wear resistance is widely used in cutting tools and mining tools.

Refractory Metal

Tungsten is the refractory metal with the highest melting point. Generally, metals with a melting point higher than 1650°C and a certain reserve and metals with a melting point higher than the melting point of zirconium (1852°C) are called refractory metals. Typical refractory metals are tungsten, tantalum, molybdenum, niobium, hafnium, chromium, vanadium, zirconium and titanium. As a refractory metal, the most important advantage of tungsten is that it has good high-temperature strength and good corrosion resistance to molten alkali metals and vapors. Only when tungsten is above 1000 ℃ does oxide volatilization and liquid-phase oxide appear. However, it also has the disadvantages of high plastic-brittle transition temperature and difficulty in plastic processing at room temperature. Refractory metals represented by tungsten are widely used in metallurgy, chemical industry, electronics, light source, machinery industry and other sectors.

Rare Metals

Tungsten is a rare metal. Rare metals usually refer to metals that are less abundant or sparsely distributed in nature. Tungsten is a widely distributed element, almost found in all kinds of rocks, but the content is low. The content of tungsten in the earth’s crust is 0.001%, and the average content in granite is 1.5×10-6. This characteristic makes its extraction very difficult, and usually it can only be separated and extracted by organic solvent extraction and ion exchange. With the advancement of science and technology, the development of metallurgical technology, equipment and analysis and detection technology, and the expansion of rare metal production scale, the purity of tungsten is continuously improved, the performance is continuously improved, and the variety is constantly increasing, thus expanding the application field of tungsten. my country is rich in tungsten ore resources, and both the output and total export volume of tungsten are the largest in the world.

Strategic Metal

Tungsten is a strategic metal. As we all know, rare metals are an important strategic resource of the country, and tungsten is a typical rare metal with extremely important uses. It is an important part of contemporary high-tech new materials. A series of electronic optical materials, special alloys, new functional materials and organometallic compounds all require the use of unique properties of tungsten. Although the amount is not large, it is very important and it is indispensable. Therefore, it is widely used in contemporary communication technology, electronic computers, aerospace development, medicine and health, photosensitive materials, optoelectronic materials, energy materials and catalyst materials.

Development History

Tungsten is a non-ferrous metal and an important strategic metal. Tungsten ore was called “heavy stone” in ancient times.

In 1781, the Swedish chemist Carl Wilhelm Scheele discovered scheelite and extracted a new element acid-tungstic acid. In 1783, it was discovered by the Spanish Depuria that wolframite also extracted tungstic acid. In the same year, Carbon reduction of tungsten trioxide gave tungsten powder for the first time and named this element. The content of tungsten in the earth’s crust is 0.001%. There are 20 kinds of tungsten minerals that have been discovered. Tungsten deposits are generally formed with the activity of granitic magma. After smelting, tungsten is a silver-white shiny metal with extremely high melting point and high hardness. Tungsten is the metal with the highest melting point.
In the 1850s, chemists discovered the effect of tungsten on the properties of steel. However, tungsten steel began to be produced and widely used at the end of the 19th century and the beginning of the 20th century.High-speed steel was exhibited for the first time at the Paris World Exposition in 1900. Therefore, the extraction industry of tungsten has developed rapidly since then. The emergence of this kind of steel marks a major technological advancement in the field of metal cutting processing. Tungsten becomes the most important alloying element.
In 1900, Russian inventor А.Н.Ладыгин first suggested the application of tungsten in lighting bulbs. In 1909, Кулидж formulated a process based on powder metallurgy and pressure processing, which made it possible for tungsten to be widely used in electric vacuum technology.
From 1927 to 1928, cemented carbide was developed with tungsten carbide as the main component, which was an important stage in the industrial development history of tungsten. The properties of these alloys surpass the best tool steels and are widely used in modern technology.

Chemical Properties

Tungsten is a rare high-melting-point metal that can increase the high-temperature hardness of steel. It belongs to the VIB group of the sixth period (the second longest period) of the periodic table. Tungsten is a silver-white metal that looks like steel. Tungsten has a high melting point, a very low vapor pressure, and a low evaporation rate. The chemical properties of tungsten are very stable. It does not react with air and water at room temperature.

When it is not heated, any concentration of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and aqua regia will not have any effect on tungsten. When the temperature rises to 80°-100 At °C, among the above-mentioned acids, except for hydrofluoric acid, other acids have a weak effect on tungsten. At room temperature, tungsten can be quickly dissolved in a mixed acid of hydrofluoric acid and concentrated nitric acid, but it has no effect in alkaline solutions. In the presence of air, molten alkali can oxidize tungsten into tungstate.

In the presence of oxidants (NaNO3, NaNO2, KClO3, PbO2), the reaction to form tungstate is more violent. It can combine with oxygen, fluorine, chlorine, bromine, iodine, carbon, nitrogen, sulfur, etc. at high temperature, but not with hydrogen.
The following is the reaction equation of tungsten

At high temperature

Reacts with oxygen group elements

2W+3O2=2WO3
W+2S=WS2
W+2Se=WSe2
W+2Te=WTe2

Reacts with halogen elements

W+3F2=WF6
W+3Cl2=WCl6
W+3Br2=WBr6
W+2I2=WI4

Physical Properties

Element symbol: W
Atomic number: 74
Number of nuclear charges: 74
CAS: 7440-33-7
Stable isotopes and their percentages: 180 (0.14); 182 (26.41); 183 (14.40); 184 (30.64); 186 (28.41)
Atomic volume: (cubic centimeter/mole) 9.53
Relative atomic mass: 183.84
The content of elements in the sun: (ppm) 0.004%
The content of elements in seawater: (ppm) 0.000092%
The electronic layer structure of a free atom: 1s22s22p63s23p63d104s24p64d104f145s25P65d46S2
Atomic radius: 137pm
Peripheral electronic layer arrangement: 5d4 6s2
Electronic layer: K-L-M-N-O-P
The propagation rate of sound in it (thin rod): (m/S) 4620
Oxidation state: Main W-4, W-2, W-1, W0, W+2, W+3, W+4, W+5, W+6
Ionization energy (kJ/mol): M-M+ 770 M+-M2+ 1700 M2+-M3+ 2300 M3+-M4+ 3400 M4+-M5+ 4600 M5+-M6+ 5900
The first ionization energy: 775kJ/mol.
Electronegativity: 1.7.
Solid density: 19.25 grams per cubic centimeter.
Liquid density: 17.6 g/cm3.
Specific heat: 130J/kg.K (300K).
Thermal conductivity: 160W/m.K (300K).
Crystal structure and lattice constant:
Radar Tungsten Steel Diamond Sapphire Mirror Watch
Radar Tungsten Steel Diamond Sapphire Mirror Watch
α-W: The unit cell is a body-centered cubic unit cell, each unit cell contains 2 metal atoms. β-W: cubic lattice a=5.046 nm (stable below 630°C)
Cell parameters:a = 316.52 pm/b = 316.52 pm/c = 316.52 pm/α = 90°/β = 90°/γ = 90°
Melting point: 3410±20℃
Boiling point: 5555°C (under a standard atmospheric pressure)
Mohs hardness: 7.5
Latent heat of fusion: 40.13±6.67kJ/mol
Sublimation heat: 847.8 kJ/mol (25℃)
Evaporation heat: 823.85±20.9kJ/mol (boiling point)
Periodic Table of the Elements Tungsten
Periodic Table of the Elements Tungsten
Temperature coefficient of resistance: 0.00482 I/℃
Electronic work function: 4.55 eV
Thermal neutron capture surface: 19.2 b
Elastic modulus: 35000-38000 MPa (wire)
Torque modulus: ~36000Mpa
Bulk modulus: 3.108×1011－1.579×107t+0.344×103t2 Pa
Shear modulus: 4.103×1011－3.489×107t+7.55×103t2 Pa
Compressibility: 2.910-7 cm/kg

There are two variants of tungsten, alpha and beta. At standard temperature and normal pressure, the α type is a stable body-centered cubic structure. β-type tungsten can only appear in the presence of oxygen. It is stable below 630°C, and is transformed into α tungsten above 630°C, and this process is irreversible.

Isotope:

Isotope	Natural Abundance	Half Life	Decay Type	Decay Release Energy (MeV)	Decay Products
¹⁸⁰W	0.12%	1.8 x 1018 years	alpha decay	2.516	¹⁷⁶Hf
¹⁸¹W	Man-Made	121.2 days	ε	0.188	¹⁸¹Ta
¹⁸²W	26.50%	1.7 x 1020 years	alpha decay	1.772	¹⁷⁸Hf
¹⁸³W	14.31%	8 x 1019 years	alpha decay	1.680	¹⁷⁹Hf
¹⁸⁴W	30.64%	1.8 x 1020 years	alpha decay	1.123	¹⁸⁰Hf
¹⁸⁵W	Man-Made	75.1 days	β⁻	0.433	¹⁸⁵Re
¹⁸⁶W	28.43%	4.1×1018 years	β⁻β⁻	1.656	¹⁸²Hf

Note: MeV is the abbreviation of Mega Electron Volt

Other Properties

Tungsten is a rare metal with a high melting point and belongs to the VIB group of the sixth period (the second longest period) in the periodic system of elements. Tungsten is a silver-white metal that looks like steel. Tungsten has a high melting point, a very low vapor pressure, and a low evaporation rate. Its main physical properties are as follows:

Element symbol &Nbsp; W
Atomic number 74
Stable isotopes and their percentages 180 (0.14); 182 (26.41); 183 (14.40); 184 (30.64); 186 (28.41)
Atomic volume 9.53 cm3/mol
Solid density: 19.35 grams per cubic centimeter.
Liquid density: 17.6 g/cm3.
Crystal structure and lattice constant α-W: body-centered cubic a=3.16524 pm (25℃)
β-W: cubic lattice a=5.046 nm (stable below 630°C)
Melting point: 3410±20℃
Boiling point: 5555℃±20℃
Latent heat of fusion 40.13±6.67kJ/mol
Sublimation heat 847.8 kJ/mol (25℃)
Evaporation heat 823.85±20.9kJ/mol (boiling point)
Temperature coefficient of resistance 0.00482 I/℃
Electronic work function 4.55 eV
Thermal neutron capture surface 19.2 b
Elastic modulus 35000~38000 MPA (wire)
Torque modulus～36000Mpa
Bulk modulus 3.108×1011－1.579×107t+0.344×103t2 Pa
Shear modulus 4.103×1011－3.489×107t+7.55×103t2 Pa

Isotope

There are five tungsten isotopes appearing in nature, and their half-lives are very long, so they can be regarded as stable isotopes. All these isotopes can be transformed into hafnium by alpha decay.

The measurable half-life is 180W, and its half-life is 1.8×1018 years. The natural decay of other isotopes has not been observed, and the half-life of forced degradation: 182W, T1/2> 8.3 years, 184W, T1/2> 29 years, 185W, T1/2> 13 years, 186W, T1/2> 27 years. Their half-lives are only theoretical values. On average, two alpha decays occur in one gram of 180W per year. Four isotopes of this element have been found, and three of them may be slightly radioactive. They are 182W, 186W, and 183W.

There are 27 man-made radioactive isotopes of tungsten, the most stable of which is 181W, which has a half-life of 121.2 days, 185W has a half-life of 75.1 days, 188W has a half-life of 69.4 days, and 178W has a half-life of 21.6 days. The half-lives of other radioisotopes are less than 24 hours, most of which are less than 8 minutes.

Species

There are more than ten kinds of main tungsten ore, and there are mainly two in China; wolframite (tungstate of manganese and iron) and scheelite (calcium tungstate ore).

Wolframite (FeMn)WO4. The colors are dark gray, light reddish brown, light brown black, brown and iron brown. Semi-metallic luster, metallic luster and resin luster. It is usually leaf-shaped, curved flake-shaped, granular and dense; some are monoclinic crystals such as thick slabs, pointed columnars, etc., which are often filled with white quartz in the form of veins in the granite and nearby rock cracks. Hardness 5-5.5, specific gravity 7.1-7.5. Ragged fracture. It is brittle and weakly magnetic. Wolframite is the main raw material for tungsten smelting and tungstate production. The traditional process uses the alkali fusion method.
Scheelite CaWO4. The color is off-white, and there are also yellow-brown, green and light red. Grease luster. It belongs to the tetragonal crystal system, forming a double-cone-shaped pseudo-octahedron or plate-shaped crystal. Sometimes, diagonal stripes can be seen on the crystal surface, and the double crystals are more common. Some crystals are shell-shaped, kidney-shaped, granular and dense. Hardness is 4.5-5; specific gravity is 5.9-6.2. It is brittle, conchoidal or jagged fracture. When irradiated by a fluorescent lamp, scheelite can emit beautiful light blue fluorescence. Scheelite minerals are produced in China’s Jiangxi Dayu, Xiushui, Hunan Rucheng, Anhua, Linwu, Henan Luanchuan, Yunnan Wenshan and other places. Many placer deposits are formed. The above tungsten minerals can be obtained by gravity separation (shaking table, jigging, etc.), flotation, chute, scouring sand method and other methods to obtain wolframite or scheelite concentrate.

Technological Development

Tungsten was discovered by the Swedish chemist Scheler in 1781. By the beginning of the 20th century, due to the development of a series of applications, such as the first exhibition of high-speed steel with tungsten as an alloying element and light bulbs made of tungsten wire at the Paris World Exposition in 1900; 1927-1928 developed tungsten carbide-based sintered hard The tungsten metallurgical industry began to be produced and developed.
In order to meet the increasing quality demands of users for tungsten products, reduce costs, and reduce environmental pollution, tungsten metallurgical technology has made considerable progress, and new advanced technologies have fully replaced traditional technologies. Mainly reflected in the following aspects:

In terms of the decomposition of tungsten mineral raw materials, the early industrialized soda pressure cooking method has been developed to not only efficiently treat scheelite concentrates and low-grade scheelite medium ore, but also process black and white tungsten mixed ore; on the basis of breakthroughs in theoretical research, The NaOH (sodium hydroxide) decomposition method has developed from only low-calcium wolframite concentrate to a general technology that can process various tungsten mineral raw materials including scheelite concentrate and refractory tungsten ore. Of course, traditional methods with low efficiency and serious environmental pollution such as NaOH fusion method, soda sintering method, hydrochloric acid decomposition method, etc. are gradually eliminated with development. At the same time, it also reduces the requirements for beneficiation and greatly improves the resource utilization rate.

In the preparation of pure tungsten compounds, the strong alkaline anion exchange purification and transformation process of crude Na2WO4 solution, short process, low cost, and high product quality have replaced the classic magnesium salt purification-traditional chemical transformation in a large range. Craft. Correspondingly, the purification and transformation of the quaternary ammonium salt extraction method has started from laboratory research and development to industrialization, presenting a promising prospect. The selective precipitation method has been successfully developed and widely used to remove molybdenum, tin, antimony, and arsenic from the tungstate solution, and has been widely used, greatly improving the purity of tungsten products and the adaptability of tungsten metallurgical processes to raw materials.

In the preparation of metal tungsten powder, in the 1970s, the advanced blue tungsten hydrogen reduction method replaced the yellow tungsten hydrogen reduction method. By the end of the 20th century, the purple tungsten hydrogen reduction method further replaced the blue tungsten hydrogen reduction method, resulting in The physical performance control of the tungsten powder has reached a more advanced level, and the quality of the tungsten powder has been further improved.

At the same time, the successful research and development of a variety of tungsten metallurgical secondary resources has greatly improved the utilization of tungsten secondary resources both in terms of technical level and recycling rate.
Science and technology are the primary productive forces. As an important strategic material, tungsten resources are important resources in the world and must be used in a rational and circular manner.

The Application Of Tungsten

Basic use: About 50% of the tungsten ore mined in the world is used for the smelting of high-quality steel, about 35% is used for the production of hard steel, about 10% is used for making tungsten wire, and about 5% is used for other purposes. Tungsten can be used to make firearms, nozzles for rocket thrusters, armor-piercing bullets, metal cutting blades, drill bits, super-hard molds, wire drawing dies, etc. Tungsten has a wide range of uses, involving mining, metallurgy, machinery, construction, transportation, electronics, chemicals, Light industry, textile, military industry, aerospace, science and technology, various industrial fields.

Tungsten is widely used in modern technology in pure metal state and alloy state. The most important alloy state is alloy steel, tungsten carbide-based cemented carbide, wear-resistant alloy and strong heat alloy. Tungsten is mainly used in the following industrial fields:

Iron and steel industry: Tungsten is mostly used in the production of special steel.

The widely used high-speed steel contains 9%-24% tungsten, 3.8%-4.6% chromium, 1%-5% vanadium, 4%-7% cobalt, and 0.7%-1.5% carbon. The characteristic of high-speed steel is that it can be automatically quenched at a high tempering temperature (700-800℃) in the air. Therefore, it maintains high hardness and wear resistance up to 600-650℃.

Tungsten steel in alloy tool steel contains 0.8%-1.2% tungsten; chromium tungsten silicon steel contains 2%-2.7% tungsten; chromium tungsten steel contains 2%-9% tungsten; chromium tungsten manganese steel contains 0.5%-1.6% tungsten.

Tungsten-containing steel is used to manufacture various tools: such as drill bits, milling cutters, wire drawing dies, female and male dies, air support tools and other parts. Tungsten magnet steel is a permanent magnet steel containing 5.2%-6.2% tungsten, 0.68%-0.78% carbon, and 0.3%-0.5% chromium. Tungsten-cobalt magnetic steel contains 11.5%-14.5% tungsten, 5.5%-6.5% molybdenum, 11.5%-12.5% cobalt hard magnetic materials. They have high magnetization and coercivity.

Tungsten carbide-based cemented carbide

Tungsten carbide has high hardness, wear resistance and refractory properties. These alloys contain 85%-95% tungsten carbide and 5%-14% cobalt. Cobalt is used as a binder metal, which gives the alloy the necessary strength. Some alloys mainly used for processing steel also contain carbides of titanium, tantalum and niobium. All these alloys are manufactured by powder metallurgy. When heated to 1000-1100 ℃, they still have high hardness and wear resistance. The cutting speed of cemented carbide tools far exceeds the cutting speed of the best tool steel tools. Cemented carbide is mainly used for cutting tools, mining tools and wire drawing dies.

Heat-strength and wear-resistant alloy

As the most refractory metal, tungsten is a component of many thermal alloys, such as 3%-15% tungsten, 25%-35% chromium, 45%-65% cobalt, 0.5%-0.75% Carbon alloys are mainly used for parts with strong wear resistance, such as the valve of aero-engines, the working parts of die-cutting knives, turbine wheels, excavating equipment, and the surface coating of plowshares.
In aviation rocket technology, as well as other sectors that require high thermal strength of machine parts, engines and some instruments, alloys of tungsten and other refractory metals (such as tantalum, niobium, molybdenum, rhenium) are used as heat-strength materials.

Contact material and high specific gravity alloy

The tungsten-copper alloy (10%-40% copper) and tungsten-silver alloy manufactured by powder metallurgy have the good electrical and thermal conductivity of copper and silver and the wear resistance of tungsten. Therefore, it becomes a very effective contact material for manufacturing working parts such as knife switches, circuit breakers, and spot welding electrodes. The composition is 90%-95% tungsten, 1%-6% nickel, 1%-4% copper high specific gravity alloy, and the use of iron instead of copper (-5%) alloy, used to make gyros The rotor of the instrument, the aircraft, the counterweight that controls the rudder, the radiation shield and the feed basket of the radioisotope, etc.

Electric vacuum lighting materials: Tungsten is used in tube production, radio electronics and X-ray technology with tungsten wire, tungsten ribbon and various forged components. Tungsten is the best material for white woven filament and spiral filament. The high working temperature (2200-2500℃) guarantees high luminous efficiency, and the small evaporation speed guarantees the long life of the filament. Tungsten wire is used to manufacture direct heating cathodes and grids of electronic oscillation tubes, cathodes of high-voltage rectifiers and indirect heating cathode heaters in various electronic instruments. Use tungsten as the counter-cathode and cathode of X-ray tubes and gas discharge tubes, as well as the contacts of radio equipment and the electrodes of atomic hydrogen welding torches. Tungsten wires and tungsten rods are used as heaters for high-temperature furnaces (3000°C). Tungsten heaters work in hydrogen gas, inert gas or vacuum.

Tungsten compounds: Sodium tungstate is used in the production of certain types of paints and pigments, as well as in the textile industry for fabric weighting and mixing with ammonium sulfate and ammonium phosphate to make fire-resistant fabrics and waterproof fabrics. It is also used in the manufacture of metal tungsten, tungstic acid and tungstate, as well as dyes, pigments, inks, electroplating, etc. Also used as a catalyst. Tungstic acid is used as a mordant and dye in the textile industry and as a catalyst for the production of high-octane gasoline in the chemical industry. Tungsten disulfide is used as a solid lubricant and catalyst in organic synthesis, such as the preparation of synthetic gasoline. When tungsten ore is processed, tungsten trioxide can be obtained, and then tungsten trioxide is reduced with hydrogen to prepare tungsten powder, which is widely used as raw material for tungsten materials and tungsten metallurgical materials.

In aviation and rocket technology, as well as in other sectors that require high thermal strength of machine parts, engines and some instruments, tungsten and other alloys for melting metals (tantalum, niobium, molybdenum, rhenium) are used as heat-strength materials.

It is these properties of tungsten that make tungsten a key research object in the field of material research in nuclear fusion reactors, especially the retention of hydrogen and its isotopes in tungsten is the frontier.

Resource Distribution

The natural reserves of tungsten in the earth’s crust are 6.2 million tons, and the recoverable reserves are 2.9 million tons. China is a large tungsten-producing country, with a tungsten resource reserve of 5.2 million tons, which is more than three times the total reserves (1.3 million tons) of 30 foreign tungsten-producing countries, and its output and export volume rank first in the world. The reserves of tungsten resources in the three provinces of Hunan, Jiangxi and Henan rank among the top three in the country. Among them, the reserves of tungsten resources in Hunan and Jiangxi account for 55.48% of the country’s total. Hunan is dominated by scheelite and Jiangxi is dominated by black tungsten. Its black tungsten resources account for 42.40% of the country’s total black tungsten resources.

China’s tungsten ore is generally distributed along the eastern coast of Guangdong on both sides of China’s Nanling Mountains, especially in the southern part of Jiangxi, with reserves accounting for more than one-half of the world. In addition, Dayu and Xiushui in Jiangxi (Southern Jiangxi), Rucheng in Hunan, Anhua, Linwu, Zixing, Tuling, Luanchuan in Henan, Ninghua in Fujian, and Guangxi, Guangdong, Gansu, Yunnan and other places.

The main sources of foreign tungsten ore are Canada, Russia, the United States, North Korea, Mongolia and other countries.

Tungsten Parts Manufacturing

Tungsten steel is a high-hardness, high-strength alloy steel that is mainly used to manufacture cutting tools, cutting tools, drill bits and other high-speed cutting mechanical parts. In order to improve the cutting performance of tungsten steel and extend its service life, a series of processing methods and technologies need to be adopted. This article will introduce you to common tungsten steel manufacturing methods.

1. Forging Tungsten

Forging is a commonly used tungsten steel manufacturing method, which mainly improves the mechanical properties of alloy steel by changing the structure and mechanical properties of the steel body. Forging tungsten alloy is usually divided into two methods: cold forging and hot forging. For large and complex tungsten steel parts, processes such as roll forging and ring forging can be used.

2. Heat Treatment

Heat treatment refers to heating steel parts to a certain temperature to cause corresponding physical and chemical changes in the material structure to improve its mechanical properties. Common heat treatment methods include quenching, tempering, normalizing, annealing, etc. Choosing the appropriate heat treatment method can effectively improve the hardness, strength, toughness and other properties of tungsten steel.

3. CNC Machining

CNC machining is an efficient, high-precision, and fast manufacturing method that is suitable for CNC machining tungsten steel parts with complex shapes. The control system of CNC machining machines can accurately control manufacturing parameters according to actual needs, and can achieve high-precision processing effects.

4. Electrical Discharge Machining

EDM is a non-contact manufacturing method with high manufacturing accuracy and good surface quality. It is suitable for processing small, difficult and high-precision complex workpieces. Electrical discharge machining uses the high temperature and high energy generated by electric discharge to perform discharge machining on local areas of the tungsten steel surface, which can achieve high-precision machining effects.

5. Wire Cutting

Wire cutting is a manufacturing method that generates high-energy electric sparks on the surface of tungsten steel to accurately cut out the required shapes and specifications. Wire cutting is a high-speed, high-precision, and low-cost processing method that is suitable for many tungsten steel processing fields.

In short, tungsten steel is a high-performance material, and its manufacturing and use require technical support. Various manufacturing methods can be used alone or combined with each other. Different manufacturing methods can be selected according to needs to improve the mechanical properties of tungsten steel. However, you need to pay attention to safety during the processing of tungsten steel and choose the appropriate processing technology to ensure processing quality and efficiency.

Production Status

After several years of development, China’s tungsten mining production scale has continued to expand, and its technological development capabilities and market competitiveness have reached a certain level. It can produce various tungsten mineral products according to the needs of users at home and abroad, and has achieved great results.

In 2006, the sales revenue of China’s tungsten industry was 31.1 billion yuan and the sales profit was 6.4 billion yuan, an increase of 7% over 2005. The sales revenue of 91 major tungsten companies in the country accounted for 63.0% of the industry, an increase of 20% over 2005. Among them, the sales revenue of mining, smelting, cemented carbide, tungsten and ferro-tungsten companies increased by 22.4%, 20.5%, and 16.5 respectively. %, 11.7% and 7.4%. In 2006, China’s tungsten exports were 31710.45 tons, an increase of only 1.8% over 2005, and the growth rate slowed down by 10.7 percentage points; the export value was US$1.09 billion, an increase of 36.3% over 2005. The import volume was 7890.9 tons, an increase of 71.5% over 2005; the import volume was US$202 million, an increase of 108.2% over 2005.

The net export volume was 23819.6 tons, a decrease of 10.3% over 2005; the net export volume was US$888 million, an increase of 26% over 2005. One ton of tungsten products exported in 2006 was equivalent to 4 tons in 2002 and 2003, 3 tons in 2004, and 1.3 tons in 2005.

In the first half of 2007, the production and operation of China’s tungsten industry showed a steady and rapid development trend. From January to June 2007, the national tungsten concentrate output was 40,309 tons (equivalent to WO365%, the same below), an increase of 18.65% over the same period of the previous year. From January to June 2007, the total export volume of tungsten products was 15343.8 tons, an increase of 8% over the same period in 2006, and the export value was US$535 million, an increase of 91.7% over the same period last year. The total amount of imported tungsten products (including tungsten concentrate) metal was 3430.2 tons, and the import value was 85.335 million US dollars, an increase of 87.5% and 121.9% respectively over the same period in 2006. The export of cemented carbide was 1245.6 tons, a year-on-year increase of 17.06%, and the export value was US$4.797477 million, a year-on-year decrease of 4.52%. The average export price was US$385,153.9/ton, a year-on-year decrease of 18.4%.
China’s tungsten ore is a monopoly resource, but it has not obtained monopoly profits. The reason is that the structure of China’s tungsten exports is unreasonable, with excessive exports and low prices. The main export of primary products with low added value is the Achilles heel of China’s tungsten industry’s foreign trade. With the development of the market, the product variety of China’s tungsten industry has gradually become complete, the market structure and industrial layout are gradually being standardized, and the price of tungsten products has basically stabilized after more than two years of rising. After 2008, industry consolidation may accelerate, and this process also breeds greater investment opportunities.

Tungsten, a non-renewable resource, is cheap and unreasonably mined, which makes China’s international status of tungsten not high. Therefore, I hope that the country will strengthen the supervision of this industry and restrict exports.

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