The temperature in aluminum casting production is typically between 650-740°C.
This temperature is adjusted based on the thickness of the casting and is not a fixed setting. Detailed temperature control primarily involves the following key parameters:
Pouring Temperature
The pouring temperature of aluminum alloys is typically between 650-740°C, with specific adjustments depending on the process type:
Die casting: The pouring temperature is higher, typically between 680-730°C. Thin-walled, complex parts can be raised to 730°C to improve fluidity; thick-walled parts are typically kept between 650-680°C.
Gravity casting: The pouring temperature is controlled between 680-740°C, and the mold is preheated to 250-300°C.
Mold Temperature
The mold should be preheated to 200-300°C to reduce the risk of thermal cracking and improve molding accuracy.
Temperature Control Difficulties
High temperatures can easily cause instrument accuracy to decrease, requiring regular calibration.
In winter, the molten aluminum temperature may drop below the standard value and requires a holding furnace to maintain stability.
What are the specific effects of excessively high molten aluminum temperatures?
1. Deterioration of Material Properties
Coarsening of Grains: When temperatures exceed 800°C, the crystal structure coarsens, leading to a decrease in the mechanical properties of the casting.
Overburning Defects: If the temperature exceeds the solidus, localized melting at the grain boundaries forms remelting balls or oxidation pores, completely brittle the material.
2. Increased Process Defects
Shrinkage and Porosity: High temperatures exacerbate liquid shrinkage, making it difficult to compensate for shrinkage during solidification, and easily forming concentrated shrinkage pores.
Oxidation Burnout: When temperatures exceed 750°C, the oxide film ruptures, significantly increasing the amount of molten aluminum burned (the burnout rate can increase by 20%-30% in the 700-800°C range).
3. Safety Risks
Explosion Hazard: Leakage of high-temperature molten aluminum into contact with water can cause a steam explosion (physical explosion) and subsequent aluminum-water chemical reaction explosion (chemical explosion), both of which are extremely powerful.
Equipment Deterioration: High temperatures accelerate the aging of tools such as molds and sand molds, shortening their service life. 4. Other Negative Effects
Enhanced Hydrogen Absorption: High-temperature molten aluminum has an increased ability to absorb hydrogen, which can lead to the formation of pores after cooling.
Sand Mold Deformation: Localized overheating causes the sand mold to expand, affecting the dimensional accuracy of the casting.
In actual production, the molten aluminum temperature must be strictly controlled within a reasonable range (e.g., 680-730°C for die casting) and should be avoided from contact with moisture.
The above temperature ranges are typical during the aluminum casting process. Professional foundries will ensure optimal temperature control. Of course, if you require large-scale custom aluminum castings, consider partnering with Mulan Metal. With 12 years of experience in aluminum casting production and processing, Mulan Metal has helped clients in over 30 countries complete their aluminum castings and has received consistent praise. We look forward to hearing from you.
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