The quality of aluminum castings has a significant impact on the performance of mechanical products. For example, the wear resistance and dimensional stability of aluminum castings in machine tools directly affect the accuracy and lifespan of the machine tools; The accuracy and surface roughness of the impeller, housing, and hydraulic components of various pumps directly affect the working efficiency, energy consumption, and cavitation development of pumps and hydraulic systems; The strength and resistance to cold and heat of aluminum castings such as cylinder blocks, cylinder heads, cylinder liners, piston rings, and exhaust pipes of internal combustion engines directly affect the working life of the engine.
The weight and size range of aluminum castings are very wide, with light ones weighing only a few grams and heavy ones reaching up to 400 tons. Thin ones have a wall thickness of only 0.5 millimeters, while thick ones can exceed 1 meter. The length can range from a few millimeters to over ten meters, meeting the usage requirements of different industrial sectors. In casting production, it is necessary to control and inspect the quality of aluminum castings. Firstly, it is necessary to establish process guidelines and technical conditions for the control and inspection of raw materials, auxiliary materials, and each specific product. Strictly control and inspect each process according to the process rules and technical conditions. Conduct quality inspection on the finished aluminum castings afterwards. Reasonable testing methods and appropriate testing personnel should be equipped. Generally, the appearance quality of aluminum castings can be judged by comparing sample blocks to determine the surface roughness of aluminum castings; Minor cracks on the surface can be inspected by coloring and magnetic particle methods. The internal quality of aluminum castings can be inspected and judged using methods such as audio, ultrasound, eddy current, X-ray, and gamma ray.
The commonly used casting methods for aluminum castings are resin sand casting and lost foam casting, followed by special casting methods such as metal mold casting, investment casting, gypsum mold casting, etc. Sand casting can be divided into clay sand molds, organic binder sand molds, resin self hardening sand molds, lost foam molds, and so on. When the wet mold cannot meet the requirements, consider using clay sand surface dry sand mold, dry sand mold or other sand molds. The weight of castings cast with clay green sand can range from a few kilograms to tens of kilograms, while castings produced with clay dry molds can weigh up to tens of tons. The casting method of aluminum castings should be adapted to the production batch. Low pressure casting, die-casting, centrifugal casting and other casting methods are only suitable for mass production due to the expensive equipment and molds.