Filament industry

Tungsten was first used to make incandescent filaments. In 1909, W.D. Coolidge in the United States used tungsten powder pressing, remelting, rotary forging, and wire drawing processes to produce tungsten wire, which led to rapid development in tungsten wire production. In 1913, I. Langmuir and W. Rogers discovered that tungsten thorium wire (also known as thorium tungsten wire) had better electron emission performance than pure tungsten wire, and began using tungsten thorium wire, which is still widely used today. In 1922, tungsten wires with excellent anti sagging properties (known as doped or non sagging tungsten wires) were developed, which was a significant progress in the research of tungsten wires. Non sagging tungsten filament is an excellent filament and cathode material widely used. In the 1950s and 1960s, extensive exploration and research were conducted on tungsten based alloys, with the hope of developing tungsten alloys that could work at temperatures ranging from 1930 to 2760 ℃ for the production of high-temperature resistant components for the aerospace industry. Among them, tungsten rhenium alloys have been extensively studied. Research has also been conducted on the melting and processing technology of tungsten, using consumable arc and electron beam melting to obtain tungsten ingots, which are then extruded and plastic processed into certain products; However, due to the coarse grain size, poor plasticity, difficult processing, and low yield of melted ingots, the melting plastic processing process has not become the main production method. Apart from chemical vapor deposition (CVD) and plasma spraying, which can produce very few products, powder metallurgy is still the main means of manufacturing tungsten products.

Sheet metal industry

China was able to produce tungsten wire in the 1950s. In the 1960s, research was conducted on the melting, powder metallurgy, and processing technology of tungsten, and it is now possible to produce plates, sheets, foils, bars, pipes, wires, and other shaped parts.

High temperature materials

tungsten alloy

tungsten alloy

Tungsten materials are used at high temperatures, and simply using solid solution strengthening methods has little effect on improving the high-temperature strength of tungsten. However, dispersion (or precipitation) strengthening on the basis of solid solution strengthening can greatly improve high-temperature strength, with ThO2 and precipitated HfC dispersed particles having the best strengthening effect. Both W-Hf-C and W-ThO2 alloys have high high-temperature strength and creep strength at around 1900 ℃. Tungsten alloys used below the recrystallization temperature are effectively strengthened by the method of warm work hardening to produce strain strengthening. If fine tungsten wire has high tensile strength, with a total processing deformation rate of 99.999% and a diameter of 0.015mm, the tensile strength can reach 438 kgf/mm at room temperature

Among refractory metals, tungsten and tungsten alloys have the highest plastic-brittle transition temperature. The plastic brittle transition temperature of sintered and melted polycrystalline tungsten materials is around 150-450 ℃, causing difficulties in processing and use, while single crystal tungsten is below room temperature. The interstitial impurities, microstructure, alloy elements, as well as plastic processing and surface state in tungsten materials, have a significant impact on the plastic brittle transition temperature of tungsten materials. Except for rhenium, which can significantly reduce the plastic brittle transition temperature of tungsten materials, other alloy elements have little effect on reducing the plastic brittle transition temperature (see strengthening of metals).

Tungsten has poor antioxidant performance, and its oxidation characteristics are similar to molybdenum. Tungsten trioxide volatilizes above 1000 ℃, resulting in "catastrophic" oxidation. Therefore, tungsten materials must be protected under vacuum or inert atmosphere when used at high temperatures. If used in a high-temperature oxidation atmosphere, protective coatings must be added.

Military weapons industry

With the progress of scientific development, tungsten alloy materials have become the raw materials for making military products today, such as bullets, armor and shells, bullet heads, hand grenades, hunting guns, bullet heads, bulletproof vehicles, armored tanks, military aviation, artillery components, firearms, etc. The armor piercing projectile made of tungsten alloy can penetrate armor with high inclination angles and composite armor, making it the main anti-tank weapon.