Low-pressure casting involves positioning the mold above a sealed crucible and introducing compressed air into the crucible to create a low pressure on the surface of the molten metal, thereby causing the molten metal to rise from the crucible, fill the riser, and solidify within the mold.

Low-pressure casting is a casting process that delivers excellent feeding, features a compact structure, and facilitates the production of large, thin-walled composite castings. It eliminates risers and achieves a metal recovery rate of up to 95%. The process is pollution-free and readily amenable to automation. However, it entails high equipment costs and relatively low production efficiency, making it typically suited for casting nonferrous alloys.

Low-pressure casting is a casting process in which liquid alloy is forced from the bottom to the top of the mold cavity under pressure and solidifies under that pressure to produce the casting. The sealed crucible is filled with dry compressed air or an inert gas. As pressure is applied to the surface of the molten metal, it flows downward into the riser. The mold is then steadily filled through the runner up to the shoe‑upper region, with filling pressures typically ranging from 20 to 60 kPa. Once the casting has fully solidified, the gas pressure on the liquid surface is released; the uncured molten metal remaining in the riser and runners flows back into the crucible under its own weight. The mold is then opened, the casting removed, and the cycle repeated.

The production process of low-pressure casting comprises the following four basic steps:

1. Metal smelting and mold manufacturing.

2. Preparations prior to pouring: These include sealing the crucible (installing the sealing lid), slag removal from the riser, liquid level measurement, leak testing, mold alignment, and securing the mold or molds.

3. Pouring: Includes liquid lifting, filling, pressurization, curing, pressure relief, and cooling, among other processes.

4. Demolding: Includes loose molding and casting.

Low-pressure casting is an early form of counter‑gravity casting that was introduced for industrial production in the 1940s. Today, low-pressure castings are primarily used to manufacture aluminum and magnesium alloy components, such as automotive wheels, engine blocks, cylinder heads, pistons, impellers, guide vanes, and other complex‑shaped castings in the automotive industry. The automotive sector places stringent demands on product quality. When producing steel castings—such as steel wheels—using low-pressure casting, risers must be made from specialized refractory materials. Low-pressure casting is also suitable for small copper‑alloy castings, including pipe fittings and bathroom valves.

Low-pressure castings feature a dense microstructure, excellent gas tightness, stable dimensional accuracy, and reduced machining requirements, making them well suited for a wide range of sealed, pressure‑bearing components. We offer custom mold development based on your drawings or samples, can tailor the casting process to meet specific operating conditions, and are capable of producing non‑standard, complex‑shaped parts and special‑specification castings to your exact specifications.