subject: Aluminum Casting Heat Treatment Process Improvement [print this page] Aluminum Casting Heat Treatment is defined as a treatment standard, control heating temperature, holding time and cooling rate, change the alloy, its main purpose is: To improve the mechanical properties, increase corrosion resistance, improved processability, dimensional stability obtained . Heat Treatment of Aluminum Casting Process can be divided into four categories as follows: annealing the aluminum alloy castings heated to a higher temperature, usually around about 300 , holding a certain time, with furnace cooling to room temperature process called annealing. In the annealing process of solid solution decomposition occurs, the second phase particles aggregate, can eliminate the stress within the casting, casting size and stability, to reduce deformation and increase the casting of plastic.
Solution heat treatment the casting is heated to temperatures as high as possible, close to the eutectic melting point, maintaining the temperature long enough, and then rapidly cooled to strengthen the group element to maximize the dissolution, this high-temperature state is fixed Save to room temperature, the process is called solution heat treatment. Solution treatment can improve the strength and ductility of castings to improve the alloy corrosion resistance. Effects of solution treatment depends on the following three factors:
(1) Enamelware. The higher the temperature, the faster the dissolution of strengthening elements, strengthening the better. Generally lower than the maximum heating temperature alloys had started firing temperature, while the lower limit of the heating temperature should be to strengthen the group element as much as possible integrated into solid solution. In order to obtain the best solution strengthening effect, but the inconvenience alloy had burned, and sometimes heated using classification methods, namely, low melting point eutectic temperature insulation, so that group dissolved element diffusion, low melting point eutectic do not exist, then to the higher temperature of heat and quenching.
(2) High Pressure Sodium Lamp. Strengthening the elements of the holding time is determined by the dissolution rate, depending on alloy type, composition, organization, casting and casting of the shape and thickness. Cast aluminum alloy holding time is much longer than the deformation is usually determined by the test, the average ratio of the same type of sand casting metal type casting to extend the 20% -25%.
Aluminum Casting Heat Treatment Process Improvement
