Low-pressure casting is an early form of counter‑gravity casting that was first 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 industry places stringent demands on quality. When producing steel castings via low-pressure casting, risers must be made from specialized refractory materials. Low-pressure casting is also suitable for small copper-alloy castings, such as pipe fittings, bathroom stopcocks, and faucets. This technology has already been industrialized abroad.

Low-pressure casting can utilize sand, metal, graphite, and other materials. Its filling process differs from gravity casting—such as metal casting and sand-mold casting—as well as from high-pressure, high-velocity die casting. It offers the following advantages:

1. Filling with pure liquid metal can enhance the purity of castings. Since molten slag typically floats on the surface of the molten metal, low-pressure casting fills the mold cavity from the bottom of the crucible via a riser, thereby preventing molten slag from entering the cavity.

2. The molten metal fills uniformly, reducing or eliminating rolling, impact, and spattering during the filling process, thereby minimizing the formation of oxide slag.

3. Low-pressure castings exhibit excellent formability. Pressurized filling of the molten metal enhances its fluidity, which facilitates the production of castings with well-defined contours and smooth surfaces, and is particularly advantageous for manufacturing large, thin-walled components.

4. Under pressure, the casting crystallizes and solidifies, allowing for complete feeding and resulting in a dense microstructure.

5. Low-pressure casting can increase the yield of molten metal. Typically, a riser is not required; the unsolidified metal remaining in the riser can be returned to the crucible for reuse, significantly boosting the yield of molten metal—often up to 90%.

6. Convenient for production and operation, with favorable working conditions, high productivity, and easy implementation of mechanization and automation.

Low-pressure casting also has certain drawbacks. The capital investment in equipment and molds is relatively high. In the production of aluminum alloy castings, the crucible tube and riser are in prolonged contact with the molten metal and are prone to corrosion and slag contamination, which can increase the iron content of the melt and degrade its mechanical properties.

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, and can tailor the casting process to meet specific operating conditions. Non‑standard, irregularly shaped parts and castings in special specifications are also available upon request.