Aluminum alloy die castings are widely used and are mass-produced. Due to the characteristics of aluminum alloys, we choose to pay attention to some matters during production. Next, MindWell will share our production experience with you.
1. Pay attention to the welding process
Because aluminum alloy die castings are active and easily oxidized during operation, a large amount of dust and moisture are easy to adhere to the surface. Therefore, during the welding process, the things attached to the surface are easy to stay on the aluminum alloy surface with laser welding. , thus affecting the quality of aluminum alloy and the effect of welding. Therefore, before welding, it is necessary to clean the surface of the aluminum alloy and remove the oil stains on the surface. At the same time, to prevent the stability threats such as explosions caused by oxidation during welding, it is also necessary to clean the oxide film on the surface.
2. Quality inspection
The quality of use refers to the ability of castings to work for a long time under different conditions, including wear resistance, resistance to cold and heat, fatigue, shock absorption, etc., as well as process properties such as machinability and weldability. In casting production, it is necessary to control and inspect the quality of castings. At first, it is necessary to formulate process rules and technical conditions for raw materials, and auxiliary materials for the control and inspection of each specific product. Each process is strictly controlled and inspected according to the process code and technical conditions. The finished castings are then inspected for quality. To be equipped with the correct testing methods and appropriate testing personnel. Generally, for the appearance quality of castings, the surface roughness of castings can be judged by comparison samples; the fine cracks on the surface can be checked by the coloring method and magnetic particle method. The internal quality of castings can be inspected and judged by audio, special, eddy current, X-ray, and gamma-ray methods.
3. Laser welding
In the subsequent production process, laser welding is often used, and its aluminum die castings will encounter various problems during laser welding, mainly because its aluminum alloy is a non-ferrous metal, which will All kinds of light to have strong reflectivity. As a more intense beam, laser light is more likely to cause reflection on the surface of aluminum alloy.
In addition, the thermal conductivity of aluminum alloy makes it easy to reflect the laser or transfer the heat of the laser when welding with the laser, which eventually leads to the failure of the welding of aluminum alloy. When laser welding aluminum alloy, you must strictly pay attention to the operation and increase the power density of the laser to prevent it from being reflected or transmitted. Try to weld the aluminum alloy with a high density at the end of the time, so that you can avoid The emergence of problems such as reflexivity.
4. What tools will be used in the production process of aluminum alloy die castings?
- Grinding and polishing adopt a vibration grinding machine, centrifugal polishing machine, and other equipment, use a grinding stone, abrasive, water, etc. in the process of vibration (rotation), to rub against the die casting to achieve the effect of deburring and polishing the surface.
- Shape correction When the casting is deformed due to solidification shrinkage, ejection deformation or edge trimming, it is necessary to correct the shape of the deformed casting. The shape correction needs to be corrected manually with a mallet or with a hydraulic press through measuring instruments and fixtures. Correction.
- Under the action of the shot-blasting wheel, the aluminum alloy die-casting shot-blasting projectile hits the surface of the casting, causing it to absorb the kinetic energy of the moving projectile and produce plastic deformation, showing residual compressive stress, thereby improving the surface strength of the casting and not afraid of lack of strength. To achieve the purpose of cleaning and summing up.
- Sandblasting uses purified compressed air to strongly spray the quartz sand flow onto the surface of the casting, using impact and friction to remove impurities such as burrs, oxide scales, and dirt from the casting. Clean the surface of the casting and roughen the surface to improve the bonding force between the coating and the substrate.
5. Low-pressure die casting
Complex aluminum alloy die-casting parts, such as cylinder heads, cylinders, crankcases, and wheel hubs for motorcycles and automobiles, are mass-produced by low-pressure casting, which not only saves metal materials and energy, but also makes it easy to manufacture equipment and molds, and castings are of high quality. Tissue dense. The solidification of low aluminum alloy die castings is carried out from top to bottom. The part away from the gate solidifies first, and then gradually moves towards the gate, and the gate solidifies. In this way, the casting can pass through the feeding of the hot metal liquid in the riser at the lower part of the gate, so as to obtain a dense structure, no shrinkage cavity, and loose aluminum alloy die-casting. In order to meet the requirements of sequential solidification of the above-mentioned low aluminum alloy die castings, it is necessary to make the temperature of the inlet and outlet of the riser tube higher than the temperature of the gate and higher than the temperature of the cavity. We adopted the method of adding an automatic heating and temperature control device at the inlet and outlet of the riser pipe to solve the key problems encountered in the low-pressure casting of complex aluminum alloy die-casting parts, and it has been proved by continuous mass production practice that the device is simple and practical