The solution to the occurrence of casting cracks in sand cast aluminum parts is as follows:
1. Improve the wall thickness of the casting structure of the sand casting aluminum parts to strive for uniformity, and make transition rounded corners at the corners to reduce stress concentration. The spokes of wheel workpieces can be made into a curved shape when needed.
2. Improve the melting quality of aluminum alloy materials by selecting refining and initial processes to remove oxide inclusions and gases in the metal industry. Control the content of impurities, choose the correct smelting process, and avoid cold cracking.
3. Extend the dwell time of aluminum casting in the mold to avoid excessive internal stress during mold opening. During the sorting and transfer process, avoid bumping and kneading.
4. Choosing the correct casting process measures to achieve simultaneous solidification in the casting of frosted aluminum castings is beneficial for avoiding hot cracks and also helps to avoid cold cracks. Correctly set the orientation and scale of the pouring and riser to ensure that the cooling speed of each part is as uniform as possible. Correctly determining its residence time in the metal mold, which is an excellent insulation container that can further homogenize the temperature at the thicker and thinner parts of the flipped aluminum casting, reduce the temperature difference between them, and reduce thermal stress.
What are the issues to pay attention to when casting aluminum castings with sand casting? Below, we will provide you with a detailed introduction:
1. Before casting aluminum castings, it is necessary to check whether the equipment is operating properly, whether lubrication is in place, whether the steel wire rope is damaged, and whether the switch is easy to use.
2. When casting aluminum parts with sand casting, it is necessary to wait for the relevant crystallizers to be filled with aluminum water before starting the operation. During casting, attention should be paid to controlling the speed and temperature.
3. Before casting, the dummy ingot head should be placed properly, and various areas should be repaired and inspected. If damaged, it should be replaced or repaired promptly.
4. Perform preheating treatment on the convection tank and related casting tools, and remember to place the filter screen properly during preheating treatment.
5. If there is too much damage to the graphite ring or there may be cracks or other conditions, it is necessary to replace the graphite ring in a timely manner.
6. At the end, the casting machine operation should be stopped first and then the water should be stopped, so that all the aluminum water inside can flow out.
7. After opening the drain hole, it is necessary to replace the plug in a timely manner and close the drain port, which can control the flow rate.
The correctness of the structure of flip sand cast aluminum parts has a significant impact on the quality of castings, the feasibility and simplicity of production processes. The structure of flip sand cast aluminum parts is equivalent to meeting the production characteristics of investment casting, so it is an example of the correct structure of some investment castings. In order to improve the quality of investment castings during the production process of sand casting aluminum parts, it is often necessary to set process ribs and holes on the investment castings as needed. Therefore, the reference size for process rib design is an application example of process holes.
Sand casting aluminum parts can be used to cast very complex parts. In order to improve the production rate and speed during use, it is possible to assemble multiple parts and welded parts that were originally produced using other methods, and after slight structural improvements, directly cast them into an investment casting. During the casting process of metal mold castings, the pouring temperature should be controlled appropriately. If the pouring temperature is too high, it will gradually cool down slowly, resulting in coarse crystallization of the product and low mechanical properties, which can easily form defects such as pinholes and pores.
If the pouring temperature of metal mold castings is too low, it will directly lead to insufficient pouring and defects such as cold shuts. Therefore, the pouring temperature is controlled according to the specific temperature of the casting structure and casting process characteristics to reduce the casting limit to a low level. During the casting process of aluminum castings, the pouring process directly affects the quality of the castings. Therefore, in the design of the casting process and mold, the shrinkage rate should be set in advance and the size of the metal mold should be continuously modified.
For the surface treatment method of sand casting aluminum parts, it is important not to rely solely on chemical methods or physical methods. The excess chemical solvent on the surface of the casting should be washed away with water. Then it is to dry or air dry naturally. If the frosted aluminum casting needs to be painted, it should be completed as soon as possible and as little contamination as possible. By adopting the correct methods and methods, the surface of the sand cast aluminum parts will become smoother and smoother.
When pouring aluminum castings with sand casting, excessively thick sprues are prone to generate wrapping air holes. So, how to pour aluminum castings with sand casting? Let’s learn more together!
1. Large aluminum castings can be poured using one or two sets of sprues, each consisting of several finer sprues.
2. For large aluminum castings with multiple partitions, it is important to avoid the occurrence of insufficient pouring defects, and the exhaust of the castings themselves is also important.
3. When using the semi metal mold casting top pouring process, when it is not convenient to set up sufficient risers, a funnel shaped gate can be set up in key parts. As the gate liquid level continues to sink, multiple supplementary pouring can be carried out to achieve sufficient shrinkage effect.
Post time: Aug-11-2023