Process Control
Due to the most significant characteristic of 6082 aluminum alloy being its content of refractory metal Mn, the appropriate presence of Mn can easily lead to intra-granular segregation and reduced solid-liquid region plasticity, resulting in insufficient crack resistance. Therefore, the casting process mainly needs to focus on three points: First, during melting, attention should be paid to controlling the temperature between 740~760℃ and stirring evenly to ensure complete melting of the metal, accurate temperature, and uniform composition. Second, during casting, consideration should be given to the fact that Mn increases the alloy's viscosity, reducing its fluidity and affecting the alloy's casting performance. The casting speed should be appropriately reduced and controlled within the range of 80~100 mm/min. Third, increase the cooling intensity and accelerate the cooling speed for the aluminum profile to help eliminate intra-granular segregation. Control the primary cooling intensity and increase the secondary cooling intensity to reduce stress concentration during casting and avoid casting billet crack defects. The cooling water pressure should be controlled within the range of 0.1~0.3 MPa.
Causes and Solutions for Aluminum Profiles Not Taking Color During Processing:
1. The anodic oxide film is too thin. The solution is to check whether the anodizing process is standardized, and whether factors such as temperature, voltage, and conductivity are stable. If there are abnormalities, adjust them accordingly to meet the standards. If there are no abnormalities, the oxidation time can be appropriately extended to ensure the film thickness meets the requirements.
2. The pH value of the dye bath is too high. In this case, acetic acid ice can be used to adjust the pH to the standard value.
3. The workpiece is left in the water tank for too long after oxidation. It is recommended to dye the workpiece promptly. If this situation has already occurred, the workpiece can be briefly activated in the anodizing tank or nitric acid neutralization tank before dyeing for better results.
4. Improper dye selection. The correct dye should be chosen.
5. The dye has decomposed or become moldy. In this case, the dye needs to be replaced.
6. The oxidation temperature is too low, resulting in a dense oxide film. The oxidation temperature can be appropriately increased.
7. Poor conductivity. This may be due to poor contact of the anodic copper rod or the cathodic lead plate, causing batch conductivity issues. Pay attention to cleaning the anodic copper rod and the cathodic lead plate to ensure good conductivity.
Because the molds for radiator profiles consist of many thin teeth and must withstand very high extrusion pressure, each tooth needs to have high strength and toughness. If there is a significant difference in performance between them, the teeth with lower strength or toughness are prone to breakage. Therefore, the quality of the mold steel must be reliable, preferably using H13 steel from reputable manufacturers or selecting high-quality imported steel. Heat treatment of the mold is extremely important; vacuum heating and quenching should be used, with high-pressure pure nitrogen quenching being the best option to ensure uniform performance throughout the mold after quenching. After quenching, triple tempering should be applied, ensuring that the mold's hardness is maintained at HRC48–52 while also having sufficient toughness. This is a crucial condition to prevent mold tooth breakage.
