Low pressure casting concept

Low-pressure casting means that the casting mold is generally placed above a sealed holding furnace containing alloy liquid. Compressed air is introduced into the holding furnace to cause a low pressure (conventional 500-2500 mbar) on the surface of the molten metal, so that the liquid metal is connected by the furnace A riser tube inside the metal and mold cavity rises to fill the mold and controls the method of solidification casting. This casting method is well packed, the castings are densely organized, and it is easy to cast large and thin-walled complex castings. Generally, no riser is required, and the metal recovery rate is high (generally more than 70%). Easy to automate. Compared with high pressure casting, the equipment cost is lower, but the production efficiency is lower. Compared with gravity casting, it is generally used to cast nonferrous alloys.

Low-pressure casting features

Low-pressure casting can use sand, metal, graphite, gypsum, etc.

1) Filling with pure metal liquid improves the purity of castings. Because the slag generally floats on the surface of the molten metal, and low-pressure casting is realized by the molten metal in the lower part of the holding furnace through the riser tube, effectively avoiding the possibility of the slag entering the mold cavity. However, the dross caused by repeated scouring inside the riser tube requires precautions, and a filter screen is generally placed during the casting process.

2) The pressurized pressure curve is adjustable. If the setting is reasonable, the filling of the liquid metal is stable, which reduces or avoids the phenomenon of tumbling, impact, and splashing of the liquid metal during filling, thereby reducing the formation of oxidized slag.

3) The moldability of the casting is good, and the filling of the molten metal under pressure can improve the fluidity of the molten metal, which is beneficial to the formation of castings with clear outline and smooth surface, and is more beneficial to the molding of large thin-walled castings.

4) The casting is crystallized and solidified under the action of pressure, which can be fully compensated and the casting structure is dense.

5) The recovery rate of the molten metal is improved. In general, no riser is needed, and the uncondensed metal in the riser can be returned to the crucible for repeated use, which greatly improves the recovery rate of the molten metal. Generally up to more than 70%.

6) The production operation is convenient, the labor conditions are good, the production efficiency is high, and it is easy to realize mechanization and automation. With the improvement of intelligence and automation technology, an automated casting line with one person, multiple machines or unmanned operation can be realized.

Low-pressure casting plus common alloys

Aluminum alloy, magnesium alloy, copper alloy, etc.

Low-pressure casting conventional casting types

Wheels of vehicles such as automobiles, motorcycles and aircraft tanks

Engine block, cylinder head, piston, etc.

Automotive gearbox shell, crankcase oil pan, etc.

Vehicle turbocharger housing, etc.

Motor shell, battery shell, etc.

Automobile suspension chassis and steering system components: such as knuckles, control arms, calipers, subframes, longitudinal beams, etc.

Impeller, wind guide wheel, propeller blade fan blade and other heterogeneous castings

Power system transmission and transformation equipment and line components: such as high-voltage switch housings, tanks, flanges, conductors, and line fittings.

Aerospace magnesium aluminum alloy castings

Missile shell

High speed rail car pillow beam, gearbox body, contact net ratchet flywheel, etc.

Lampshade shell, etc.

Vehicle rearview mirror, mirror housing, etc.

Faucet and other bathroom plumbing parts

Other types of castings