Brief Introduction to Material Selection and Forming Methods of Cast Aluminum Parts

2026-05-28 16:25:48

The material selection of cast aluminum parts is mainly based on the working conditions, performance requirements, and cost budget of the components. The commonly used cast aluminum alloys are divided into four categories.

Al Si alloys are the most widely used type, with silicon content ranging from 4% to 13%. Eutectic Al Si alloys (with a silicon content of 11% -13%) have good fluidity and a narrow solidification range, making them suitable for thin-walled complex castings. The hypoeutectic Al Si alloy (with a silicon content of 4% -10%) can refine the eutectic silicon structure and improve plasticity through modification treatment.

Al Cu alloy has high room temperature and high temperature strength, but its corrosion resistance is relatively average, and it has a high tendency towards hot cracking. It is commonly used in components that can withstand high loads, such as certain engine pistons and cylinder heads. The Al Mg alloy has good corrosion resistance and surface glossiness, but poor casting flowability, making it suitable for components with requirements for corrosive environments. Al Zn alloys can achieve high strength under natural aging conditions, but their density is relatively high.

The selection of molding method is related to batch size, precision, and internal quality requirements. Sand casting is suitable for single piece small batch and large castings, with low mold cost but average surface quality. Metal mold casting is suitable for medium batch production, with high casting accuracy and surface quality. Pressure casting is suitable for large quantities of thin-walled complex parts, with high production efficiency but a tendency for large internal porosity. Low pressure casting is suitable for rotating bodies or shape symmetric components that require high internal density. Investment casting is suitable for precision small castings with good surface smoothness.

The reasonable matching of materials and forming methods is the basis for obtaining qualified cast aluminum parts.