Material selection of steel mold for aluminum casting

In the aluminum casting industry, the material selection of steel molds is crucial, which directly affects the performance, life and quality of the final aluminum castings.

First of all, the mold steel should have the characteristics of high hardness and high strength. For example, H13 steel has a high hardness and can withstand the high pressure generated by the aluminum liquid during the pouring process without deformation. During aluminum casting, liquid aluminum will exert a large pressure in the mold. If the mold material is not hard enough and has insufficient strength, it is easy to cause the mold to collapse or deform, affecting the dimensional accuracy of the casting.

Secondly, good wear resistance is also an important consideration. Steels such as Cr12MoV contain alloy elements such as chromium and have excellent wear resistance. Because during each demolding process of aluminum castings, the surface of the steel mold for aluminum casting will rub against the casting, and frequent casting operations will cause the mold surface to wear. Wear-resistant materials can reduce this wear and extend the service life of the mold.

Furthermore, thermal fatigue performance cannot be ignored. The melting point of aluminum is relatively low, but the temperature change during the casting process will still cause thermal shock to the mold. Select steel with excellent thermal fatigue performance, such as 5CrNiMo, which can maintain good performance in repeated heating and cooling cycles and reduce cracks caused by thermal stress.

In addition, there are certain requirements for the corrosion resistance of steel. Although aluminum itself is relatively active, there may be some additives or impurities in the casting process, which may corrode the steel mold for aluminum casting. Steels containing corrosion-resistant elements such as nickel can show better stability in this situation.