In the manufacturing industry, gravity casting molds are key tools for producing metal parts, and their service life directly affects production efficiency and cost control. Therefore, the selection of mold materials is particularly important in this process.

The working environment of gravity casting molds is extremely harsh. During the casting process, the molds need to withstand complex conditions such as the impact of high-temperature metal, high pressure, and rapid cooling. This makes the performance of the mold material a key factor in determining whether it can maintain sufficient hardness and toughness under extreme conditions, thereby ensuring the long-term and stable use of the mold.

When selecting mold materials, hardness and wear resistance are the primary properties to consider. During the use of gravity casting molds, they will be eroded and worn by molten metal. If the hardness of the selected material is insufficient, the mold surface will wear quickly, causing it to fail. Taking aluminum alloy gravity casting molds as an example, their working conditions are usually harsh. The temperature of the aluminum alloy molten liquid is generally between 650℃ and 700℃, and it is pressed into the mold cavity at high speed. Therefore, the mold material must have high hardness and excellent wear resistance to cope with this extreme environment.

Thermal fatigue resistance is also an important consideration when selecting mold materials. Gravity casting molds undergo alternating high-temperature heating and rapid cooling during the casting process. The alternating stress generated by this thermal expansion and contraction may cause thermal fatigue cracks on the mold surface. Therefore, it is crucial to prefer materials with high thermal fatigue resistance to extend the service life of the mold. For example, H13 steel is widely used in the manufacture of gravity casting molds due to its excellent thermal fatigue resistance and thermal cracking resistance.

In addition to hardness and thermal fatigue resistance, the corrosion resistance of the material cannot be ignored. During the gravity casting process, impurities and oxides in the molten metal may react chemically with the mold material, causing corrosion on the mold surface. If the corrosion resistance of the selected material is insufficient, the mold surface will be rapidly eroded, significantly reducing its service life. Therefore, selecting materials with excellent corrosion resistance is of great significance for protecting the mold surface and extending the service life of the mold.