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Defects in die casting: defects caused by the alloy

Defects in die casting: defects caused by the alloy

Die casting is a meticulous manufacturing process that requires precision and control to produce metal parts with complex shapes and different strengths and tolerances. The ability to produce components with high precision is one of the most outstanding advantages of zinc die casting. Still, it is also precisely this high degree of precision that requires absolute control of possible manufacturing errors or defects to avoid them. In some cases, errors are caused by impurities in the zinc alloys used, which can cause significant damage to the castings. The defects caused by the alloy in die casting can be intergranular corrosion or accelerated erosion of the components.

Impurities and intergranular corrosion

Elements such as lead (Pb), cadmium (Cd) or tin (Sn) pose a risk to the parts resulting from the casting process, as they can generate impurities and intergranular corrosion. This type of corrosion compromises structural integrity by weakening the grain boundaries of the material, which is a severe problem for the industry, jeopardising both the durability and the quality of the components.

The solution to this scenario is drastic but effective: the crucible must be completely emptied and cleaned to remove impurities and prevent possible future defects in the castings. At this point, it is essential to remember that contaminated alloys can be reintroduced into the supply, perpetuating the defects. Therefore, getting rid of them is not enough; it is necessary to locate the root cause, which can be found at any point in the casting process, starting with the storage or handling stages. 

Breaking the cycle of reintroducing defective alloys back into the supply and ensuring the quality of the manufactured parts is crucial to avoid impurities and intergranular corrosion. 

Zinc overheating

Zinc overheating is the second cause of possible casting defects caused by the alloy. Among the problems that can arise is the loss of aluminium (Al) and magnesium (Mg), which leads to the formation of zinc dross, an undesirable residue that can affect the quality of the final product.

Additionally, overheating can lead to accelerated erosion of critical components in die casting production, such as the syphon, piston and crucible. This erosion, aggravated by the possible dissolution of Iron (Fe) in the zinc, threatens the durability of the tools used in the process.

Excess iron in alloys

In addition to intergranular corrosion and zinc die casting defects, excessive iron in alloys can also pose a risk to production. This is because, on the one hand, it contributes to forming Fe-Al intermetallic particles, which negatively impacts the quality and homogeneity of the resulting material. Excess iron also increases the loss of aluminium. It reduces the fluidity of the cast material, which affects the filling capacity of the moulds and leads to parts with structural defects.

Jegan, zinc die casting 

The quality of die castings is directly linked to the alloys' purity. This is why rigorous quality control will ensure that defects in details and alloys are minimised as far as possible. At Jegan, thorough quality controls are carried out during all stages of zinc die casting, with the goal of a zero-defect process. 

Among the zinc alloys, zamak die casting stands out thanks to its ability to produce batches of high consistency and repeatability, maintaining constant dimensions, with robust and dimensionally complex parts, ideal for applications in sectors such as automotive, household appliances or electronics. If you need more information or have questions about Jegan's services or products, please contact us and join our social media community.