Hello, the purpose is as follows
Tungsten was first used to make incandescent filaments. Tungsten rhenium alloys have been studied extensively. The melting and forming technology of tungsten is also studied. Tungsten ingots are obtained by consumable arc and electron beam melting, and some products are made by extrusion and plastic processing; However, the melting ingot has coarse grains, poor plasticity, difficult processing and low yield, so the melting plastic processing process has not become the main production method. In addition to chemical vapor deposition (CVD) and plasma spraying, which can produce very few products, powder metallurgy is still the main means to manufacture tungsten products.
Folding sheet industry
In the 1960s, research was carried out on tungsten smelting, powder metallurgy and processing technology. Now it can produce plates, sheets, foils, bars, pipes, wires and other profiled parts.
Folding high-temperature materials
The use temperature of tungsten material is high, and it is not effective to improve the high temperature strength of tungsten simply by using solution strengthening method. However, dispersion (or precipitation) strengthening on the basis of solid solution strengthening can greatly improve the high temperature strength, and the strengthening effect of ThO2 and precipitated HfC dispersion particles is the best. W-Hf-C and W-ThO2 alloys have high high temperature strength and creep strength at about 1900 ℃. It is an effective way to strengthen the tungsten alloy used below the recrystallization temperature by adopting the method of warm work hardening to produce strain strengthening. If the fine tungsten wire has high tensile strength, the total processing deformation rate is
99.999% fine tungsten wire with diameter of 0.015 mm, tensile strength of 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 about 150~450 ℃, causing difficulties in processing and use, while that of single crystal tungsten is lower than room temperature. Interstitial impurities, microstructures and alloying elements in tungsten materials, as well as plastic processing and surface state, have great influence on the plastic brittle transition temperature of tungsten materials. Except that rhenium 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 metal strengthening).
Tungsten has poor oxidation resistance. Its oxidation characteristics are similar to that of molybdenum. Tungsten trioxide volatilizes above 1000 ℃, resulting in “disastrous” oxidation. Therefore, tungsten materials must be protected by vacuum or inert atmosphere when they are used at high temperature. If they are used in high-temperature oxidation atmosphere, protective coatings must be added.
Folding military weapons industry
With the development and progress of science, tungsten alloy materials have become the raw materials for making military products today, such as bullets, armor and shells, bullet heads, grenades, shotguns, bullet heads, bulletproof vehicles, armored tanks, military aviation, artillery parts, guns, etc. The armor piercing projectile made of tungsten alloy can break through the armor and composite armor with large inclination angle, and is the main anti tank weapon.
Tungsten alloys are alloys based on tungsten and composed of other elements. Among metals, tungsten has the highest melting point, high temperature strength, creep resistance, thermal conductivity, electrical conductivity and electron emission performance, which are of great importance, except for a large number of applications in the manufacture of cemented carbides and alloy additives.
Tungsten and its alloys are widely used in the electronics and electric light source industries, as well as in the aerospace, casting, weapons and other sectors to make rocket nozzles, die-casting molds, armour piercing bullet cores, contacts, heating elements and heat shields.
Post time: Nov-17-2022