Strength carries the world quality and controls the future
Characteristics of graphite material
Graphite material Graphite material is the most widely used friction pair material. It has the following characteristics:
(1) Good corrosion resistance.
(2) It has good temperature resistance.
(3) Good thermal conductivity and low linear expansion coefficient.
(4) Good pairing performance.
(5) Easy to process. Graphite materials used for mechanical seals are roughly divided into the following categories. Roasted graphite. During the roasting of graphite, due to the volatilization of the substances in the binder and the polymerization, decomposition and carbonization of the binder, pores (with 10% to 30% pores) will appear. As a sealing ring, permeability leakage will occur, and the strength is low. Therefore, it is necessary to carry out the impregnation treatment to fill the gap and enhance the strength. That is, after the impregnation treatment, it becomes an impermeable product, and the strength is also improved. However, the temperature resistance and corrosion resistance have decreased to varying degrees. There are three main types of impregnates used: organic resins, inorganic substances and metals. Resin bonded graphite. It is to crush the sintered graphite, use phenolic resin or epoxy resin as the binder, and then press and sinter it into products. The resin in the matrix becomes carbon particles after sintering, so it is breathable graphite. It is suitable for mass production due to its poor thermal conductivity and large linear expansion coefficient. Low cost, mainly used for low load sealing of automobile cooling water pump and household appliances.
Graphite codes include:
① Carbon graphite, code M121, temperature resistance 350 ℃.
② Graphite impregnated with epoxy resin, codes M106H, M120N, M220N, service temperature 200 ℃.
③ Graphite impregnated furan resin, code M106K, M120K, operating temperature 200 ℃, is a common material for mechanical seals of centrifugal pumps, with a wide range of applications.
④ Graphite aluminized, code M232L, service temperature 400 ℃. In addition, graphite is impregnated with antimony, silver and copper.
⑤ Graphite is impregnated with phenolic resin, which is not alkali resistant, and the service temperature is 170 ℃. ⑥ Graphite impregnated glass, code M120, M162.
⑦ Antimony impregnated graphite material, which is used for high temperature pumps, is used at about 300 ℃, but the price is relatively expensive.
Graphite for functional material development: develop high-purity graphite, isostatic pressure graphite, fluorinated graphite, silicified graphite, sealing materials, graphite heat dissipation/conductive materials, polymer composites, etc. It is applied to the fields of electronics, new energy, national defense and military industry.
Our province is a large province of graphite resources, with resource reserves ranking the first in the country, concentrated resource distribution, excellent ore quality and outstanding resource advantages. The government work report proposes to accelerate the construction of a modern industrial system, vigorously develop strategic emerging industries, and extend the graphite deep processing industry chain, which points out the direction for the relevant graphite enterprises to promote technological iteration and industrial upgrading. Ye Yingchun, the deputy of the Provincial People's Congress, suggested that the graphite intensive processing industry should be developed in the mode of "government+universities+enterprises" to play the role of "key variables" in scientific and technological innovation.
It is reported that graphite has many physical and chemical properties, such as high temperature resistance, high thermal conductivity and conductivity, thermal shock resistance, flame resistance, high compressive strength, high corrosion resistance, low friction and self-lubrication. It is mainly used in coatings, powder metallurgy, steel making, refractory materials, lubricants and batteries. It is also used in large fuel cells, batteries and lightweight high-strength composites. By 2022, China's graphite output accounted for more than 60% of the global output.