Low pressure casting refers to placing the mold above a sealed crucible, and then introducing compressed air into the crucible to create a low pressure on the surface of the molten metal, so that the molten metal rises from the crucible, the riser fills the mold and controls the solidification casting method.

Low pressure casting is a kind of large thin-walled composite castings with good feeding, compact structure and easy casting, with no riser and high metal recovery rate.95% of the casting method. No pollution, easy to realize automation. However, the equipment cost is high and the production efficiency is low, and it is usually used for casting non-ferrous alloys.

Low pressure casting is a casting method,ByThe liquid alloy is pressed under pressure into the cavity from bottom to top and solidified under pressure to obtain a casting. The sealed crucible is filled with dry compressed air or inert gas. With pressure on the surface of the molten metal, the molten metal flows down the riser. The mold is stably filled into the upper through the runner, and the filling pressure is usually20-60kPa. After the casting is completely solidified, the air pressure on the liquid surface is released, and the unsolidified molten metal in the riser and runner flows into the crucible with its own weight, and then the mold is opened for casting, and then taken out.

The production process of low pressure casting includes the following four basic processes:

1. Metal smelting and mold manufacturing.

2. Preparation work before pouring: including crucible sealing (installation of sealing cover), slag removal in the standpipe, liquid level measurement, sealing test, mold matching, mold or mold fastening, etc.

3. Pouring: including liquid lifting, filling, pressurizing, curing, pressure relief and cooling, etc.

4. Demoulding: including loose molding and casting.

Low pressure casting is an earlier anti-gravity casting technology, inUsed in industrial production in the 1940 s. Nowadays, low-pressure castings are mainly used to produce aluminum and magnesium alloy parts, such as automobile wheels, cylinder blocks, cylinder heads, pistons, impellers, wind guides and other castings with complex shapes in the automotive industry. The automotive industry has high quality requirements. When using low-pressure casting to produce cast steel (such as cast steel wheels), the riser must be made of special refractory materials. Low pressure castings can also be used for small copper alloy castings, such as pipe fittings, bathroom cocks, etc.