6082 ALUMINUM EXTRUSION BAR belongs to Al-Mg-Si series heat-treatable-strengthened aluminum alloy with moderate strength, good weldability and corrosion resistance, and is mainly used in transportation and structural engineering, such as bridges, cranes, roof structures, Transportation vehicles and transport ships, etc. In this paper, an experimental study on the application of 6082 aluminum alloy in the production of extruded profiles is carried out to determine the appropriate extrusion process system.
Taking into account the main features of 6082 ALUMINUM EXTRUSION BAR and combining with practical production, the extrusion process is formulated as follows:
(1) The 6082 alloy has a large deformation resistance, so the heating temperature of the ingot should be on the upper limit (480 ~ 500 ℃).
(2) The temperature of the die is preferably 460°C, and the temperature of the extrusion cylinder is 440-500°C.
(3) The extrusion speed is controlled within the range of 7 ~ 11m/min;
(4) In order to make the main strengthening phase of the alloy Mg2Si completely solid solution, it is necessary to ensure that the quenching temperature is above 500 °C, so the extrusion outlet temperature of the profile should be controlled within the range of 500 to 530 °C;
(5) 6082 alloy has high quenching sensitivity, and requires high quenching cooling strength and fast cooling speed, and online quenching must be carried out immediately after the product is out of the front beam. For profiles with a wall thickness of less than 2.5mm, cooling and quenching with strong wind can be considered; profiles with a wall thickness of more than 2.5mm must be quenched with water mist, and the temperature must be rapidly reduced to below 50°C.
(6) 6082 ALUMINUM EXTRUSION BAR should be stretched and straightened, and the stretch rate should be controlled within the range of 1.0% to 2.0%.
2 Statute of limitations
Aging is the last link for the profile to achieve the specified mechanical properties. A reasonable aging system should not only ensure the performance of the product, but also consider the production efficiency and production cost. Combined with the experimental research, the optimal aging system for 6082 profiles is set as follows: the aging temperature is 170-180 °C, the holding time is 8 hours, and the parking time of the profiles before aging does not exceed 8 hours.
According to the characteristics and performance requirements of 6082 ALUMINUM EXTRUSION BAR, the above process is more reasonable. In the melting and casting process, the composition control of 6082 ALUMINUM EXTRUSION BAR focuses on the range of Mn and Cr content. The optimal control range of Mn content is 0.6% to 0.65%, the content of Cr should be controlled below 0.15%, and the total amount of (Mn+Cr) should be controlled within the range of 0.70% to 0.80%. The Mg2Si content should be controlled at 1.5% to 1.6%, and the excess Si content should be controlled at about 0.3%. In the extrusion process, the control of the extrusion outlet temperature and the quenching effect is the key to ensuring the performance of the product. The quenching temperature should be guaranteed to be above 500 °C, and the extrusion outlet temperature of the profile should be controlled at 500 to 530 °C. quick.