Bearing is a kind of sliding parts commonly used in mechanical industry, and its material is different from metal, nonmetal and composite materials.Learn More
First, we can understand the relevant characteristics of graphite. 1. high temperature resistance, high melting point of graphite, 3850 ℃ in vacuum, increase at low pressure, and increase temperature of 2200 degrees. Unlike general data, when the temperature increases, graphite not only does not soften, but increases its strength, but increases its tensile strength by twice when it is 2500 ℃. 2. special thermal shock resistance, the thermal expansion of graphite is anisotropic, so the micro expansion coefficient is not large, and the volume of graphite is not changed under the condition of sudden temperature change. In addition, it has excellent thermal conductivity, so the thermal shock resistance of graphite is outstanding. As mentioned above, graphite parts should be able to work stably at high temperature for a long time.
In general, compared with other graphite equipment such as heat preservation cover and heater, the flap pot is the same data, same manufacturer and same working environment. Why is the life of the pot far lower than that of the heat preservation cover and heater?
The main reason for cracking of the triple pot is quartz crucible. 1. because the density of molten silicon is larger than solid silicon, the bottom material of the pot will break the quartz crucible during cooling, and the quartz crucible is attached to the triple valve pot. When the stress produced by the cracking of the quartz crucible is greater than the stress of the triple valve crucible, the triple valve crucible will crack. This is to say, if the bottom material of the pot is too much, the triple valve pot will be broken. This is to say, if the bottom material of the pot is too much, the triple valve crucible will be broken The cause of the pot. 2. if the heating time is too long, the quality of the quartz crucible is not over-standard and the raw material pH is not up to the requirements, silicon leakage and silicon permeability will be caused. After the gap between the fused silicon infiltrated into the three valve pot is cooled, one is to break the three-way pot, the other is to make the three-way pot bond with each other, and make it separate from each other during furnace cleaning, which can cause cracking. 3. in the heating process, only the heat source of the three-way pot comes from two aspects: one is the radiation of the heater, the other is from the conduction of the quartz crucible, which leads to the uneven heating of the three-way pot, which expands in some directions, shortens in other directions, and then causes the triple flap pot to crack.
The components of the heat field, such as heater, three-way pot, graphite holder and thermal screen, are all made of graphite. In the process of production, often encounter the phenomenon of heating equipment damage, so what is the reason for the damage of graphite equipment, what measures should be taken to extend the life of graphite equipment? The damage of graphite equipment is mainly caused by human and deterioration. As long as the human side strengthens the management and strengthens the staff's defense awareness, the loss can be reduced to the lowest point. Deterioration is the first thing to discuss here.
Graphite is a crystalline deposit of carbonaceous elements, and its crystal framework is hexagonal layered structure. The distance between each mesh layer is 340pm, and the distance between carbon atoms in the same mesh layer is 142pm;. It belongs to hexagonal crystal system with perfect lamellar cleavage. The cleavage surface is mainly composed of molecular bonds and has weak attraction to molecules, so it has good natural floatability.
Graphite products maintain the original chemical characteristics of flake graphite, and also have strong self-lubricating properties. The specially processed graphite has the characteristics of corrosion resistance, good thermal conductivity and low permeability. It is widely used in making heat exchangers, reaction tanks, condensers, incinerators, absorption towers, coolers, heaters, filters, pumps and other equipment. These equipment are used in petrochemical, hydrometallurgy, acid and alkali production, synthetic fiber, paper and other industrial sectors, which can save a lot of metal materials. With the continuous development of science and technology, people have developed many new uses for graphite. Flexible graphite products, also known as expanded graphite, is a new kind of graphite products. In addition to the characteristics of natural graphite, it also has special flexibility and elasticity. Therefore, it is an ideal sealing material. It is widely used in petrochemical, atomic energy and other industrial fields. The world market demand is increasing year by year.
Graphite products, especially graphite mattresses, can produce negative oxygen ions after heating, activate the surrounding articles, maintain human health, effectively prevent aging, and make skin full of luster and elasticity. The pan and pot made of graphite are heated quickly, and the cooked food is heated evenly from the inside to the outside. The heating time is short. It not only tastes pure, but also can lock the original nutrition of the food. Crucibles and related products are made of graphite. They are shaped and fire-resistant crucibles and related products. They have high fire resistance and low thermal expansion. In the process of melting metal, they are also stable when they are moistened and washed by metal. They have excellent thermal shock stability and excellent conductivity at high temperature. Therefore, graphite crucibles and related products are widely used in the process of direct melting metal.
At room temperature, the chemical properties of carbon are relatively stable, insoluble in water, dilute acid, water, etc
Dilute alkali and organic solvent; react with oxygen at high temperature to produce carbon dioxide or carbon monoxide; in halogen, as long as fluorine can react directly with elemental carbon; under heating, elemental carbon is easily oxidized by acid; at high temperature, carbon can react with many metals to form metal carbides. Carbon is reductive and can temper metals at high temperatures. In addition, recent studies have found that graphite can be dissolved by chlorosulfonic acid to form a chlorosulfonic acid "solution" of monolayer graphene.