What factors are due to the failure of die casting molds

1. Thermal fatigue, cracking, damage and failure.

In the production of die-casting, the mold is repeatedly stimulated by cold and heat, and the molding surface and its interior are deformed. Continue to expand. Once the crack expands, molten metal squeezes in, and repeated mechanical stresses accelerate the crack propagation. For this reason, on the one hand, the mold must be fully preheated at the beginning of die casting. In addition, the mold must be kept in a certain working temperature range during the die-casting production process to avoid early cracking failure. At the same time, it is necessary to ensure that there are no problems with the internal factors before and during the production of the mold. In actual production, most mold failures are thermal fatigue cracking failures. (Guide: Analyze the surface super hardening treatment technology of stainless steel welded pipe mold)

2. Fragmentation failure

Under the action of the injection force, the mold will initiate cracks at the weakest part, especially if the marking marks or electrical machining marks on the molding surface of the mold are not polished, or the clear corners of the molding will be the first Microcracks appear, and when there are brittle phases or coarse grains in the grain boundaries, it is easy to break. However, the crack propagation is very fast during brittle fracture, which is a very dangerous factor for the fracture and failure of the mold. For this reason, on the one hand, all scratches and electrical machining marks on the mold surface must be polished, even if it is in the pouring system, it must be polished. In addition, the mold material used is required to have high strength, good plasticity, good impact toughness and fracture toughness.

3. Dissolution failure

Commonly used die-casting alloys are zinc alloy, aluminum alloy, magnesium alloy and copper alloy, and there are also pure aluminum die-casting. Zn, Al, Mg are more active metal elements, and they have a good affinity with mold materials, especially Al is easy to bite. When the mold hardness is high, the corrosion resistance is better, and if there are soft spots on the molding surface, the corrosion resistance is unfavorable.

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