The main difference is that the process is different, the characteristics are different, the application is different, as follows:
One, the process is different
1, pressure casting
Pressure casting is a kind of liquid or semi-solid metals or alloys, or liquid metals or alloys containing enhanced material phases, under high pressure at high velocity to fill into the cavity of the die casting model, and make the metal or alloy under the Pressure solidification casting method.
2, low-pressure casting
Low-pressure casting is the liquid alloy under pressure from the bottom up into the casting cavity, and solidified under pressure to obtain casting casting method.
Two, different characteristics
1, pressure casting
Advantages:
①, high productivity, easy to mechanize and automate, and can produce thin-walled castings of complex shapes.
②, castings of high dimensional accuracy, surface roughness value is small.
③, die-casting parts can be embedded casting parts, not only to save valuable materials and machining hours, but also replaces the assembly process of parts, you can eliminate the assembly process, simplify the manufacturing process.
Disadvantages:
①, die casting liquid metal filling speed is high, the cavity gas is difficult to completely exclude, castings are prone to pores and cracks and oxidized debris and other defects, die casting usually can not be heat treatment.
②, die-casting mold structure is complex, long manufacturing cycle, high cost, not suitable for small batch casting production.
3, by the die-casting machine clamping force and mold size limitations, not suitable for the production of large-scale die castings.
④, the alloy type is restricted, zinc, magnesium, copper and other non-ferrous alloys.
2, low-pressure casting
Advantages:
①, pure metal liquid filling, improve the purity of castings.
②, the liquid metal filling smooth, reduce or avoid the liquid metal in the filling of the flip, impact, splash phenomenon, thus reducing the formation of oxidized slag.
3, casting good molding, liquid metal filling under pressure, can improve the fluidity of the liquid metal, conducive to the formation of clear contours, surface finish castings, for the molding of large thin-walled castings is more favorable.
4, castings under pressure crystallization and solidification, can be fully complementary shrinkage, casting organization dense.
5, improve the rate of liquid metal, generally do not need a riser, and rising liquid tube in the metal can be returned to the crucible, re-use, so that the rate of liquid metal greatly improved, the rate of general up to 90%.
Disadvantages:
Larger investment in equipment and molds; in the production of aluminum alloy castings, the crucible and the ascending liquid tube in contact with the liquid metal for a long time, it is easy to be eroded and scrapped, and it will also make the liquid metal to increase the iron and deterioration of performance.
Three, the application of different
1, pressure casting
Mainly used in mass production of non-ferrous alloy castings. In the production of die casting, accounting for the largest proportion of aluminum alloy die casting, for 30% to 50%, followed by zinc alloy die casting, copper alloy die casting accounted for 1% to 2%. The application of die casting is the most automobile, tractor manufacturing industry, followed by instrument manufacturing and electronic instrument industry, again for agricultural machinery, national defense industry, computers, medical equipment and other manufacturing industries. Produced by die-casting method parts are engine cylinder block, cylinder head, transmission case, engine cover, instrumentation and camera shell and bracket, pipe joints, gears and so on.
2, low-pressure casting
Low-pressure casting is mainly used for the production of aluminum alloy, magnesium alloy parts, such as the automotive industry of the automobile wheel hubs, internal combustion engines, cylinder block, cylinder head, piston, missile shells, impellers, wind turbine, such as the shape of the complexity of castings, the quality of the requirements of the high. When the use of low-pressure casting production of cast steel, such as cast steel wheels, liquid-raising tubes need to use special refractory materials. Low-pressure casting can also be applied to small copper alloy castings, such as pipe fittings joints, bathrooms in the cork faucet, etc., the technology has been industrialized production in foreign countries.
Baidu Encyclopedia-Pressure Casting
Baidu Encyclopedia-Low-Pressure Casting