In recent years, graphite has gradually become the preferred material for mold making due to its good physical and chemical properties. Graphite molds are widely used in various fields.
1. Graphite molds for non-ferrous metal continuous casting and semi-continuous casting
In recent years, advanced production methods such as direct continuous (or semi-continuous) manufacturing of rods or pipes from molten metal have been promoted at home and abroad. This method has begun to be used in copper, copper alloys, aluminum, aluminum alloys, etc., in China. Artificial graphite is considered a suitable material as a mold for continuous casting or semi-continuous casting of non-ferrous metals. Production practice has proved that due to the use of graphite molds, factors such as good thermal conductivity (thermal conductivity determines the solidification speed of metal or alloy), good self-lubricating properties of the mold, etc., not only increase the casting speed, but also because the ingot has accurate dimensions, smooth surface, and uniform crystal structure, it can be processed directly in the next process. This not only greatly improves the yield rate and reduces waste loss, but also greatly improves product quality.
2. Mold for pressure casting
Artificial graphite materials have been successfully used in the pressure casting of non-ferrous metals. For example, zinc alloy and copper alloy castings produced from pressurized casting molds made of artificial graphite materials have been used in automobile parts and other aspects.
3. Graphite mold for centrifugal casting
Graphite molds have been successfully used in centrifugal casting. The United States has used artificial graphite molds with wall thicknesses above 25 mm to centrifugally cast bronze casings. In order to prevent the artificial graphite mold from burning, certain anti-oxidation measures can be taken. After casting a certain number of castings, if it is found that the inner surface of the casting mold is burned, the size of the inner hole of the casting mold can be enlarged so that it can be used to cast large-sized casings.
4. Hot pressing mold
Artificial graphite hot pressing molds are used for pressure sintering of cemented carbide and have the following characteristics:
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 a dense sintered body can be obtained after a short period of sintering.
5. Graphite mold for glass molding
Because graphite material has chemical stability, it is not easily wetted by molten glass, and does not change the composition of the glass. Graphite material has good thermal shock resistance and small size changes with temperature. Therefore, it has become an indispensable mold material in glass manufacturing in recent years. It can be used to make glass tubes, elbows, funnels, and other molds for various special-shaped glass bottles.
6. Sintered graphite molds and others
Using the characteristics of minimal thermal deformation of artificial graphite materials, sintering molds and brackets for transistors can be manufactured. It is now widely used and has become an indispensable material for the development of the semiconductor industry. In addition, graphite molds are also used in casting molds for cast iron, durable casting molds for various non-ferrous metals, casting molds for cast steel, casting molds for heat-resistant metals (titanium, zirconium, molybdenum, etc.), and thermite welding molds for welding rails.