The heat treatment process for sand-cast aluminum parts mainly includes four methods: annealing, solution treatment, aging treatment, and thermal cycling.
The specific operations are as follows:
1. Annealing: Heat the casting to approximately 300℃, hold at that temperature, and then cool in the furnace. The purpose is to eliminate internal stress, stabilize dimensions, and improve plasticity. For ingots, homogenization annealing (temperature close to the melting point, holding for 12-24 hours) is required to eliminate compositional inhomogeneities.
2. Solution Treatment: Heat to near the eutectic melting point (e.g., 500℃), and rapidly cool (water quenching or polymer solution) to fully dissolve the reinforcing components and fix them at high temperature, improving strength and corrosion resistance. The cooling rate must be ≥50℃/second.
3. Aging Treatment: Natural aging: Place at room temperature for several days to allow the supersaturated solid solution to decompose slowly.
Artificial aging: Heating to 120-190℃ and holding for several hours, or using multi-stage aging (lower temperature first, then higher temperature) to balance strength and corrosion resistance. For example, 6063-T6 requires aging at 175℃ for 8 hours.
4. Thermal cycling treatment: Multiple heating and cooling cycles (e.g., quenching at 850-900℃ followed by tempering at 550-600℃) utilize the contraction and expansion of the solid solution lattice to stabilize the second phase, suitable for precision parts.
Precautions: Deformation control: Avoid excessively rapid cooling; higher temperature water or polymer solution quenching can be used instead.
Performance verification: Temperature and time must be strictly controlled to avoid performance failures due to improper processes.
Through the above processes, sand-cast aluminum parts can significantly improve mechanical properties, dimensional stability, and corrosion resistance. Of course, professional casting companies usually handle the heat treatment of various castings properly, because different industries have different strength requirements for castings. If you need to customize large quantities of sand-cast aluminum parts, you can choose to cooperate with Mulan Metal. Mulan Metal has 12 years of experience in the production and processing of sand-cast aluminum parts and has helped customers in more than 30 countries complete the commissioned production of various sand-cast aluminum parts. We look forward to your cooperation consultation.
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