In low-pressure casting, the mold is placed in a sealed holding furnace, with the mold cavity connected to the molten metal in the furnace via a riser. During operation, compressed air is introduced into the furnace, causing the molten metal to flow from the riser into the mold cavity. After the molten metal solidifies, the compressed air in the furnace is released, and any remaining liquid metal flows back into the furnace through the riser.

The aluminum hubs and blades in the torque converter core are produced using low-pressure die casting, which offers four key advantages: a compact structure and excellent mechanical properties; high process yield. Statistics show that the qualified‑rate for low-pressure die casting exceeds 93%, while the yield for gravity die casting of the same part ranges from 70% to 80%; superior production efficiency—die‑casting delivers three times the productivity of gravity die casting for the same product; and a smooth surface finish, thereby reducing machining allowances.

Below, we will introduce the production process of low-pressure casting:

1. Mold inspection: Before using the mold, clean off any paint residue. At the end of the production cycle, if the paint has deteriorated or the surface is no longer smooth, grind it with an abrasive wheel, then remove aluminum chips from the ejector pins and clean the vent plugs.

2. The operating temperature of the baking mold is (360±10)°C; therefore, the mold should be baked to this operating temperature prior to low-pressure casting.

3. Coating: When the mold is heated to 300°C, apply the coating by spraying. The coating must be uniform and free of runs or drips. Its primary functions are: to prevent corrosion of the mold cavity by the aluminum alloy and to extend the service life of molds used in low-pressure die casting; and to prevent the aluminum alloy from adhering to the cavity or parting surface, thereby enabling continuous, high‑speed production. Additionally, the coating forms an insulating protective layer on the cavity, allowing molten metal to flow into the cavity smoothly, reducing flow resistance and enhancing the filling performance of the molten aluminum.

4. Setting process parameters. The key process parameters for low-pressure casting are the molten aluminum temperature, the pressurization rate of the equipment, and the pressure setting. These three factors directly affect the quality of low-pressure castings. Incorrect parameter settings can lead to defects such as sand adhesion and insufficient filling. Therefore, proper parameter configuration is critical in low-pressure casting.

5. Low-pressure casting pouring.

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.