Aluminum die casting has the advantages of low cost, good manufacturability, resources and energy saving, so it becomes more and more popular. Sand casting is frequently used in aluminum die castings, mainly because sand casting has lower cost than other casting methods. It also has simple production process and short production cycle. Now, I will introduce the quality requirements of aluminum die casting.
1. Casting speed: The casting speed of aluminum die castings is directly proportional to the depth of the ingot liquid cavity. If the casting speed increases, the depth and temperature gradient of the ingot will increase, which will cause a section of the liquid cavity to appear at the bottom of the liquid cavity which will lead to greater shrinkage stress, and ultimately increasing the probability of ingot hot cracking. So that is why we need to control the speed.
2. Casting temperature: A good casting temperature for aluminium die castings will keep the liquid metal flowing well, thereby reducing structural stress and preventing cracks. Generally, the casting temperature should be determined according to the type of material and the specifications of the ingot. If the temperature is not appropriate, it will increase the internal stress which will cause cracks in the casting. Too low temperature is also not good, because this will cause defects such as cold barriers, slag inclusions, and even cracks on the surface of the ingot. Even more serious, it may make the casting unable to continue.
3. Liquid level height: The position of the liquid level is also very important. If it is too low, the hot cracking tendency of the material will increase which might affect the die casting process. If the liquid level is too high, it will increase the segregation degree of the ingot. Therefore, it is necessary to ensure a suitable liquid level. Too high or low liquid level will both affect the results.
4. Aluminum die castings must not have defects such as cracks, cold barriers, sand holes, pores, slag holes, shrinkage porosity, and oxidation slag inclusion.
5. The non-processed surface of aluminum die-casting parts should be smooth and straight, and the casting marks should be clear. After pouring and riser cleaning, the surface of the casting should be flush.
6. Aluminum die-casting parts shall not be hammered, blocked or dipped to eliminate leakage.