Problems needing attention in the production of aluminum alloy die castings
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admin *
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2022/03/14 10:44:40 *
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With the continuous expansion of the application scope of aluminum alloy die casting products in the market, domestic aluminum alloy die castings have developed rapidly in recent years. At present, many people in the industry pay attention to whether the market is good or not. Die casting aluminum alloy is also a kind of die casting. The knowledge introduced below is also about die casting. What will be introduced specifically?
1. Alloy composition control starts from the purchase of alloy ingots. Alloy ingots must be alloy ingots based on ultra-high purity aluminum and made of ultra-high purity aluminum, magnesium and copper. The supplier has strict composition standards. High quality aluminum alloy material is the guarantee of producing high-quality castings.
2. Clean and dry stacking area shall be ensured for purchased alloy ingots to avoid white rust caused by long-term exposure to humidity, or increased slag generation and metal loss caused by factory dirt pollution. A clean factory environment plays an important role in the effective control of alloy composition.
3. The ratio of new material to recycled material such as water inlet shall not exceed 50%. Generally, new material: old material = 70:30. Aluminum and magnesium in continuous remelting alloy decrease gradually.
4. When remelting the nozzle material, the remelting temperature must be strictly controlled not to exceed 430 ℃ to avoid the loss of aluminum and magnesium.
5. Qualified die-casting factories adopt centralized melting furnace to melt aluminum alloy, so that the alloy ingot and furnace return material are evenly proportioned, and the flux can be used more effectively to keep the alloy composition and temperature uniform and stable. Electroplating wastes and fine scraps shall be separately smelted in the furnace.
Many times, high-quality aluminum alloy die castings can be made without paying attention to the above problems. If the aluminum alloy die castings have the following defects, some treatment methods are provided below.
Since the causes of each defect come from many different influencing factors, we should solve the problems in actual production. In the face of many reasons, is it right or wrong to adjust the machine first? Or do you want to refuel first? Or modify the mold first? It is suggested to deal with it according to the degree of difficulty, from simplicity to complexity, in the following order:
1) Clean parting surface, cavity and ejector rod; Improve coating and spraying process; Increase the clamping force and the amount of metal poured. These measures can be implemented by simple operation.
2) Adjust process parameters, injection force, injection speed, mold filling time, mold opening time, pouring temperature, mold temperature, etc.
3) For refueling, select high-quality aluminum alloy ingot, change the proportion of new material and returned material, and improve the smelting process.
4) Modify the mold, modify the gating system, increase the inner gate, and add overflow slot, exhaust slot, etc.
For example, the reasons for flash of die castings are:
1) Die casting machine problem: the clamping force is not adjusted correctly.
2) Process problem: the injection speed is too high and the pressure impact peak is too high.
3) Mold problems: deformation, sundries on the parting surface, uneven wear of inserts and sliding blocks, and insufficient strength of the formwork.
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