Because the die-casting mold is exposed to high temperature, high pressure, and high-speed working environment for a long time, periodic stress and strain are generated on the surface of the mold. After a certain period of use, cracks, ablation, cracks, and other damages will occur, resulting in the mold being unable to continue to be used. It needs to be repaired before it can continue to be put into production.
In the use of die-casting mold, how to ensure the production of qualified products, while extending the service life of the mold? The following measures to improve the service life of die-casting die are discussed.
1. Defects in the mold material itself
The conditions of the use of die casting belong to the environment of urgent heat and cold, and the characteristic die steel with cold, and heat resistance, good fracture toughness, and high thermal stability should be selected. According to relevant information, the most widely used mold materials are Swedish 8407, American H13 (4Gr5MoVlSi), Japanese SKD61, and German 2344. The correct selection of die steel material and the use of high-strength alloy material can improve the service life of the die.
2. Die casting mold processing, use, repair, and maintenance
During the die-casting process, it is impossible to set the injection speed too high or too low. Therefore, the maximum injection speed setting for aluminum die-casting should not exceed 53m/s, the minimum injection speed is set to 18m/s, and the average injection speed is set to 43m/s. After EDM processing of the mold cavity, the hardened layer must be removed or the stress must be relieved. Otherwise, cracks, pitting and cracking will occur on the mold surface during use. However, after the mold has been used for 50,000 mold times, it can be maintained once every 25,000 to 30,000 mold times. Using the above method, the speed and time of mold cracking caused by thermal stress can be significantly slowed down.
3. Heat treatment of mold
The correctness of heat treatment is directly related to the service life of the mold. Therefore, the following points should be paid attention to during heat treatment;
a. When the forging is cooled to room temperature, spheroidizing annealing is performed.
b.Add quenching and tempering treatment after rough machining and before finishing machining.
c. During heat treatment, attention should be paid to the decarburization and carburization of the cavity surface.