The rational use of aluminum alloy die-casting molds is very important for our production efficiency and product quality. Aluminum alloy die-casting molds are very prone to cracks after a period of production. At this time, we need to take some preventive measures in advance.
3 precautions
- The aluminum alloy die-casting mold is prone to high temperatures during the die-casting production process, so it is best to add a cooling system, which is very helpful for the continuous use of the mold.
- During the die-casting production process of aluminum alloy die-casting molds, unreasonable spraying of the release agent will also cause great damage to the production molds, and attention should be paid during the production process.
- Unsatisfactory heat treatment of aluminum alloy die-casting molds is a common problem, mainly due to hardness. Generally, if the hardness is not less than HRC-47, there will be no problems.
Aluminum alloy die-casting molds have the following points for attention in production and use:
- Aluminum alloy metal liquid enters the cavity at high pressure and high speed, which will cause intense friction and impact on the surface of the molded parts, causing erosion and wear on the surface of the mold.
- It is inevitable that molten slag will be brought in during the pouring process of aluminum alloy metal. The slag will have a very complicated chemical effect on the surface of the formed part. For example, if the zinc in the copper alloy diffuses to the surface of the production mold quickly, it will be Forming a more brittle compound, the compound produced by the reaction of aluminum and iron acts like a wedge, which accelerates the formation and development of cracks.
- Thermal stress is the main cause of cracks on the surface of molded parts produced by production molds. In the process of producing each aluminum alloy die-casting, in addition to being washed by the high-speed and high-pressure liquid metal, the surface of the formed die-casting also absorbs the heat released by the metal during the solidification process, resulting in heat exchange.
- In addition, due to the heat conduction of the production mold material, the temperature of the surface layer of the formed part rises sharply, resulting in a large temperature difference from the inside, resulting in internal stress. When the molten metal fills the mold cavity, the surface layer of the cavity first reaches a high temperature and expands, while the inner mold temperature is lower, and the relative expansion is small, causing the surface layer to generate compressive stress. After the mold is opened, the surface of the cavity is in contact with the air, and it is cooled by compressed air and paint to generate tensile stress. This alternating stress increases with the continuation of production. When the fatigue limit of the mold material is exceeded, the surface layer produces Plastic deformation produces cracks at grain boundaries.