Graphite molds should still be unfamiliar to many people. thatGraphite mouldWhat are the excellent performances? How should it be applied? Speaking of this, do you have any curiosity?
Graphite mould for continuous casting and semi continuous casting of nonferrous metals
In recent years, advanced production methods such as directly continuous (or semi continuous) production of bars or tubes from the molten metal state are being promoted at home and abroad. This method has been used in copper, copper alloy, aluminum and aluminum alloy in China. Artificial graphite is considered as the most suitable material for continuous casting or semi continuous casting molds of non-ferrous metals. The production practice has proved that the graphite mold not only improves the casting speed due to its good thermal conductivity (which determines the solidification speed of metal or alloy) and good self-lubricating performance, but also can be directly processed in the next process due to its accurate size, smooth surface and uniform crystal structure. This not only greatly improves the yield and reduces the waste loss, but also greatly improves the product quality. Continuous casting methods include vertical continuous casting method and horizontal continuous casting method.
Mold for glass molding
Because graphite material has chemical stability, is not easy to be infiltrated by molten glass, does not change the composition of glass, has good heat-resistant impact performance, and has small size change with temperature, it has become an indispensable mold material in glass manufacturing in recent years. It can be used to make glass tubes, bends, funnels and other molds of various special-shaped glass bottles.
Mold for pressure casting
Artificial graphite has been successfully used in pressure casting of nonferrous metals. For example, zinc alloy and copper alloy castings produced by pressure casting molds made of artificial graphite have been used in automobile parts
Graphite mould for centrifugal casting
Graphite mould has been successfully used in centrifugal casting. The United States has adopted artificial graphite mold with wall thickness of more than 25 mm to centrifugally cast bronze sleeve. In order to prevent the burning loss of the artificial graphite mold, certain anti-oxidation measures can be taken. After casting a certain number of castings, if it is found that the inner surface of the mold is burned, the size of the inner hole of the mold can be expanded to cast large-scale casing pipes.
Sintered graphite mouldAnd other diamond sintered graphite molds
Artificial graphite can be used to manufacture sintering dies and supports for transistors due to its extremely small thermal deformation. It has been widely used and has become an indispensable material for the development of semiconductor industry. In addition, it is also used in cast iron molds, durability molds for various non-ferrous metals, cast steel molds, heat-resistant metals (titanium, zirconium, molybdenum, etc.) molds, and thermite welding molds for rail welding. The electronic sintered graphite mold used for hot press sintering diamond tools plays the dual role of heating element and mold support in the manufacturing process of diamond tools. The quality of graphite mold directly affects the dimensional accuracy and appearance shape of diamond tools. Hot press sintering process requirements: the temperature reaches (1000 ± 2) ℃, the forming pressure is 16 ~ 50 MPa, the holding time is 15 ~ 30 min, and the environment is non vacuum. Under this working condition, the graphite mold for forming and heating elements is required to have conductivity, high resistivity and sufficient mechanical strength, as well as good oxidation resistance and long service life, so as to ensure the dimensional accuracy and excellent performance of diamond tools. At present, the graphite mold materials for diamond tool manufacturing in western developed countries are mainly graphite materials with ultra-fine particle structure, high purity and high graphitization degree, and their average particle size is required to be less than 15 μ m. Even 10 μ M U.M or less, medium pore size less than 2 μ m。 The graphite mold made of this carbon material has small porosity, compact structure, high surface finish, strong oxidation resistance, and an average service life of 30-40 times. The Diamond Mold requires high hardness, good oxidation resistance and high machining accuracy. The use of high-quality graphite raw materials greatly extends the service life of the mold and improves the oxidation resistance.
Hot pressing die
The artificial graphite mold has the following characteristics when it is used for pressure sintering of cemented carbide: first, if the pressing temperature is increased to 1350-1450 degrees, the required unit pressure can be reduced to 67-100 kgf / cm2
(that is, 1 / 10 of the cold pressing pressure); Second, pressing and heating are carried out in the same process, and the compact sintered body can be obtained after a short time of sintering
1. Excellent thermal and electrical conductivity
2. Low linear expansion coefficient, good thermal stability and heat shock resistance
3. Chemical corrosion resistance: it is not easy to react with most metals 4. At high temperature (above 800 ℃ for most copper matrix sintering temperature), the strength increases with the increase of temperature
5. It has good lubrication and abrasion resistance
6. It is easy to process and has good machining performance. It can be made into a mold with complex shape and high precision.
