The heat treatment of aluminum castings actually belongs to a type of post-treatment process in casting, which is carried out after the completion and cleaning of aluminum castings. In addition, it will also involve post-treatment processes such as shaping, rough machining, and rust prevention treatment, and their actual application is based on requirements.
Post casting treatment is the final process in the production of aluminum castings, which has a significant impact on the quality of aluminum castings. But different post-treatments have different corresponding effects. In terms of heat treatment, it is used to improve or change the original structure of aluminum castings, with the aim of eliminating internal stress in aluminum castings, ensuring casting performance, and preventing casting deformation and damage.
Heat treatment of aluminum castings generally includes quenching, annealing, normalizing, as cast quenching and tempering, artificial aging, stress relief, softening, and graphitization treatment, targeting different working conditions. For example, castings require high wear resistance and sufficient toughness, and their internal structure should be austenitic. For this purpose, it is necessary to perform quenching treatment on the castings. The castings can be heated to the austenite region to fully austenitize them, and then rapidly quenched with water and quenched, so that the austenite cannot transform in time and remain unchanged.
The post-treatment of aluminum castings can be divided into three aspects: correction, repair, and surface finishing. Some castings may experience varying degrees of deformation during solidification, cooling, and heat treatment, resulting in some dimensions exceeding the tolerance. Therefore, correction methods are needed for repair. Correction is mainly carried out using mechanical force at room temperature or in a warm state. When the deformation is too large, high-temperature correction can also be carried out in the heating furnace using the casting's own weight or external pressure.
The external defects of aluminum castings are mainly repaired by welding methods; The rough and uneven surface of castings is generally polished with hanging grinding wheels and high-speed grinding wheels. Rough machining is a post-processing technology for localized aluminum castings. After rough machining, defects can be detected and resolved in a timely manner, weight can be reduced, and waste and chips can be classified and reused. And rust prevention treatment is adopted to prevent aluminum castings from rusting during transportation or storage, using the method of brushing primer.