Aluminum Alloy Die Casting Process Flow: A Complete Breakdown from Raw Material to Finished Product

Aluminum Alloy Die Casting Process Flow: A Complete Breakdown from Raw Material to Finished Product

Aluminum alloy die casting is a systematic industrial process that requires the coordination of six core stages to transform metal raw materials into precision components. Strict parameter control is essential at each step to ensure product quality.

Raw Material Melting marks the starting point of the process. Aluminum ingots with a purity of over 99.5% are mixed with alloying elements such as silicon, magnesium, and copper in specific proportions, then fed into an intermediate frequency induction furnace and heated to 650-720°C. During melting, refining agents are added to remove impurities, and nitrogen or argon is introduced to prevent oxidation. The end result is a homogeneous aluminum alloy melt with low gas content, whose purity directly impacts the mechanical properties of subsequent castings.

Mold Preparation is a critical prerequisite. Molds are typically made of H13 hot-work die steel and consist of two parts: the moving mold and the fixed mold. Inside, they feature a cavity matching the part’s shape, as well as a gating system and venting system. Before use, molds must be preheated to 150-300°C to avoid cracks caused by contact between the low-temperature mold and high-temperature aluminum melt. Additionally, a release agent is sprayed onto the cavity surface to reduce aluminum adhesion and extend mold life.

Die Casting Molding is the core process, performed using a die-casting machine. First, the aluminum alloy melt is rapidly injected into the mold cavity through the shot chamber at a velocity of 3-15 m/s, with a specific pressure usually ranging from 50-150 MPa. This ensures the melt quickly fills the complex cavity and expels trapped gas. Next, pressure is maintained (dwell time: 5-30 seconds) to allow full solidification of the melt in the cavity. Finally, the mold opens, and an ejection mechanism pushes out the casting. The entire molding cycle takes only tens of seconds, making it suitable for mass production.

Gating/Riser Removal and Cleaning follow immediately. Freshly molded castings have excess structures like gates and risers, which are removed via mechanical cutting (e.g., sawing, milling) or high-pressure water jets. Subsequently, shot blasting or sandblasting is used to treat the surface, eliminating oxide scales and burrs. This reduces the casting’s surface roughness to Ra3.2-Ra6.3μm while enhancing surface adhesion, laying the foundation for subsequent processing.

Heat Treatment Strengthening is conducted as needed. For castings requiring improved strength, T6 heat treatment is applied: the casting is first heated to 520-540°C for soaking (solution treatment), rapidly cooled in water, then held at 120-180°C for aging treatment. This forms uniform precipitates inside the alloy, ultimately increasing tensile strength by 30%-50% to meet the requirements of structural components.

Quality Inspection is the final checkpoint. Visual inspection is performed to identify surface defects, while X-ray flaw detection and ultrasonic testing are used to detect internal pores and cracks. A coordinate measuring machine verifies dimensional accuracy (ensuring compliance with IT8-IT10 standards). Only qualified castings proceed to subsequent surface treatment or assembly, ensuring consistent product quality throughout the process.