What are the principles and production processes of low-pressure casting?

What are the principles and production processes of low-pressure casting?

Low pressure casting is a casting method that presses liquid alloys into the mold cavity from bottom to top under pressure, and solidifies under pressure to obtain castings. The principle of low-pressure casting is shown in Figure 1. A sealed crucible is filled with dry compressed air or inert gas, and with the help of the pressure acting on the metal liquid surface, the metal liquid is smoothly filled into the mold from bottom to top along the riser through the runner, with a filling pressure of generally 20-60kPa.

After the casting is completely solidified, release the gas pressure on the liquid surface to allow the non solidified metal liquid in the riser and runner to flow into the crucible by its own weight, then open the mold and remove the casting.

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

1) Preparation of metal smelting and molds or molds.

2) Preparation before pouring: including sealing the crucible (assembly of sealing cover), scraping slag in the riser, measuring the liquid level height, sealing test, mold matching, tightening the mold or casting, etc.

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