As one of modern industry ceramics, silicon carbide ceramics is a new synthetic inorganic nonmetallic material. The hardness of it is only lower than diamond, with excellent resistance to chemical corrosion, wear resistance, high temperature performance and high mechanical strength, good self-lubricating properties, high temperature creep, small coefficient of friction, high thermal conductivity, low coefficient of thermal expansion, For the oil, metallurgy, chemical, machinery, aviation, aerospace atomic energy and other fields, commonly used to do the mechanical seal of the friction material. A large number of experiments show that silicon carbide is the best material in the current friction pair, especially the best performance of pressureless sintered SiC and hot pressing sintered SiC.
At present, the domestic production of pressureless sintered silicon carbide main performance indicators are close to the level of similar foreign products. Although the properties of hot-pressed sintered silicon carbide are the best, the manufacturing cost is expensive and has not been widely used. Using the excellent characteristics of SiC, widely used in shielded pumps and magnetic pump field.
Silicon carbide thermal expansion coefficient is 1/4 of stainless steel, when the medium temperature is high, with the same with the stainless steel parts with gaps or interference caused by bearing damage; fracture toughness is stainless steel 1/50, the material is more brittle Force when the action is easy to break, especially the edges and corners.
Elasticity is 1/50 of stainless steel, mechanical more brittle, easy to break. Thermal expansion coefficient is 1/4 of stainless steel, and its (stainless steel) with the attention should be.
If a diameter d = 50 (mm) rotor shaft (stainless steel) is used on a pump with a liquid temperature of 100 ° C, the following problem will occur: the clearance between the sleeve and the rotor shaft will reach 0.052 mm, Between the gap at room temperature (20 ℃) reduced 0.052mm. To obtain the gap at room temperature, the gap between the sleeve and the rotor shaft becomes larger. Therefore, the casing at room temperature is easy to break, and then used in high temperature liquid is more prone to failure.
The features of silicon carbide made by DXseal are as following:
1.Special structure, can automatically compensate for the radial temperature rise caused by differences in material expansion, so that the pump can 0 ℃ -250 ℃ temperature range of normal operation.
2.Life is more than 10 times the ordinary graphite sleeve.