The main reasons for the failure of zinc and aluminum alloy die casting are as follows:
1. Fracture failure: Under the action of injection force, cracks will occur in the weakest part of the die, especially when the scratches on the surface of the die or the marks of electrical processing are not polished, or when the first micro-cracks appear in the corner clearance of the die, when there are micro-cracks. Brittle crystals or coarse grain boundaries are liable to fracture. Brittle fracture is a very dangerous factor for crack propagation. Therefore, on the one hand, any scratches and electrical machining marks on the surface of the die must be polished, even if it is in the parts of the casting system, it must also be polished. In addition, the die material used has high strength, good plasticity, impact toughness and fracture toughness.
2. Thermal fatigue cracking failure: In die casting production, the die is repeatedly stimulated by cold and heat, forming surface and internal deformation, dragging each other and repeatedly generating thermal stress, resulting in structural damage and toughness loss, resulting in micro-micro-micro-micro-micro-micro cracks, and continue to expand, Zhongshan Fahrenheit Fushun Special Steel said, once it happens. Cracks. The expansion of molten metal and repeated mechanical stress all accelerate the propagation of cracks. For this reason, on the one hand, the die must be fully preheated at the beginning of die casting. In addition, in the process of die casting, the die must be kept within a certain temperature range to avoid early cracking failure. At the same time, we must make sure that the mold has no problem before and after manufacture. Due to actual production, most die failures are thermal fatigue cracking.
3. Solve failure: Zinc alloy, aluminum alloy, magnesium alloy and copper alloy are commonly used in die casting die, while pure aluminum die casting, zinc, aluminium, magnesium and other metal elements have high activity and good affinity with die materials, especially aluminum is easy to bite the die. When the die hardness is higher, the corrosion resistance is better. If the soft surface is formed, the corrosion resistance is poor.
In the production process, often because of the damage of parts and stop. By means of CT scanning technology, substitutes for these parts can be rapidly produced, thus improving the utilization rate and service life of the equipment.