Cast aluminum undergoes three stages of heat treatment: heating, heat preservation, and cooling. Several parameters, such as heating speed, heating temperature, heat preservation time, cooling speed, and heat treatment period, can be used to describe the entire process. Temperature is critical in each heat treatment process specification. If the temperature measurement is inaccurate, the heat treatment process specification cannot be properly implemented, resulting in a decrease in the quality of aluminum castings or even scrapping. The key to heat treatment technology and the most important factor affecting deformation is temperature measurement and control. Another important reason is the effect of the cooling process on the deformation of aluminum die castings after quenching. The thin part of the metal heat treatment always cools quickly, while the thick part cools slowly. When actual production needs are met, the difference between thickness and thickness of workpiece should be minimized in order to reduce the distortion and cracking tendency of the transition zone due to stress concentration. Aluminum castings are processed after they've been heated. Reverse deformation and pre-expansion holes at the shrinkage end are used to improve the qualified rate of deformation after quenching, according to the deformation law of the castings.
1Datum is a term that refers to the selection of a date.
For element selection, die cavity dimension inspection, casting marking, and die machining, the datum plane must be established. The casting's outer circle, plane, inner hole, and end face can all be used as reference planes. Design, processing, and casting all agree on the appropriate datum plane. When choosing a datum, keep the following points in mind:
a. The non-machined surface is typically chosen as the investment casting's reference plane. It is preferable to choose a machining surface with a lower machining allowance if one is available.
b. the datum must be chosen in conjunction with the surface to be processed in order to meet precision requirements, and the design datum and the processing process datum of the parts must be as close as possible.
c. Because the number of datum planes is limited by six degrees of freedom, three base surfaces are usually chosen (two base surfaces are chosen for rotating parts), and the line marking and processing are done on the same base plane.
2Cast aluminum part structural design
The quality of castings, the feasibility and simplicity of production technology, and the production cost are all influenced by the structure of castings. The investment casting's structure should match the investment casting's manufacturing characteristics. The reasonable structure of a part of the casting is demonstrated.
Process ribs and process holes are frequently set on the casting according to the needs in order to ensure the quality of the casting. The use of process rib is demonstrated in this example. The process rib design's reference dimensions are shown. A process hole application example is shown.
Complex parts can be cast by pouring molten metal into molds. After slight structural improvement, the assembly and welding of several parts produced by other methods can be directly cast into a molten casting to improve productivity and accuracy. A structural example of multiple parts assembly and welding parts transformed into the entire casting of the molten mold is shown.
3Casting structural elements and process parameters selection
Because the inner surface of the mold shell is smooth and dry, and it is typically poured by hot shell, the investment casting wall thickness can be designed thinner. The recommended small wall thickness values as well as the possible small values for various alloy castings are shown. Thin wall thicknesses of 30% to 50% less than the small value in the table can be cast for local parts.
Die casting has a broad range of applications. Aluminum casting is a metal forming method for completing the process of less chip and no chip. It is widely used and rapidly developing. Die casting alloys have gradually expanded to include cast iron and steel castings, and are no longer limited to non-ferrous metals such as zinc, aluminum, magnesium, and copper. Die casting part size and weight are determined by the die casting machine's power. The shape size of the casting can range from a few mm to 1 2m, and the weight can range from a few grams to dozens of kilograms, thanks to the increased power of die casting machines. Die casting is no longer restricted to the automotive and instrument industries, but is gradually expanding to include agricultural machinery, machine tooling, electronics, national defense, computer, clock, camera, and everyday hardware. New technologies in die casting, such as vacuum die casting, oxygen injection die casting, precision and density die casting, and the use of soluble core, are presented.