Common failure types and causes of die-casting dies
During the use of the mold, some breakdowns often occur, using a very serious impact mold and other defects, below the standard part, it is understood that die-casting mold in the production process, the most common forms of failure: fracture failure, failure and dissolution.
Three kinds of thermal fatigue crack damage and failure, and three reasons for failure are also introduced in detail.
Fracture failure
Under the action of injection pressure, the most vulnerable part of the mold crack initiation, especially on the surface of the molding line trace or electrical machining trace has not been completed, or formed a clear corner of the place will be the first small crack in the grain boundary brittle phase or coarse grain, that is, easy to fracture. The risk factors are rapid crack growth, brittle fracture and failure of die. Therefore, on the one hand, in the mold surface scratches, electrical machining marks must be polished, even if it is in the pouring system, but also must be illuminated. It also requires high strength, advanced materials, good plasticity, excellent impact toughness and fracture toughness.
Second. Corrosion failure
Commonly used molds and zinc alloys, casting alloys, aluminum alloys, magnesium alloys and copper alloys, but also pure aluminum die casting, zinc metal elements, aluminum, magnesium is a lively, they have a good affinity for mold materials, especially aluminum sheets. When the die hardness is high and has good corrosion resistance, if the molding surface has soft spots, it is anti-corrosion.
Three, thermal fatigue crack damage failure
In the production of die casting dies, the surface chilling effect and its internal deformation occur again and again in hot forming. Thermal stresses circulate repeatedly among them, resulting in structural damage and loss of elasticity, resulting in the appearance of microcracks, which continue to propagate as cracks propagate, fluid diaphragm and molten metal, and repeated mechanical stresses accelerate cracks. Extension. Therefore, on the one hand, the die casting die must be fully preheated and started. In addition, in the process of die casting mold must be maintained in a certain operating temperature range to avoid early cracking failure. At the same time, ensure that before and after the mold production and internal production is not a problem. In actual production, the failure of mould is the most thermal fatigue crack failure.
