Understand the car model material structure and characteristics, in order to use the correct method in daily maintenance, correct look at the aging of the car model.
1. Poor corrosion resistance. When the alloy composition of impurity elements lead, cadmium, tin over the standard, resulting in the aging of the casting and deformation, the performance of the volume swell, mechanical properties, especially plastic significantly decreased, a long time or even rupture. Lead, tin and cadmium in zinc alloy solubility is very small, and thus concentrated in the grain boundary and become the cathode, aluminum-rich solid solution into the anode, in the presence of water vapor (electrolyte) conditions, to promote intergranular electrochemical corrosion. Die casting is aged due to intergranular corrosion.
2. Aging The structure of zinc alloy is mainly composed of zinc-rich solid solution containing Al and Cu and Zn-rich Al-rich solid solution, and their solubility decreases with the decrease of temperature. However, due to the rapid casting of the die casting speed, so to room temperature, the solubility of solid solution is greatly saturated. After a certain period of time, this supersaturation will be gradually lifted, leaving the shape and size of the casting slightly changed.
3. Zinc alloy die castings should not be used in high temperature and low temperature (0 ¡æ below) working environment. Zinc alloy at room temperature has good mechanical properties. But at high temperature tensile strength and low temperature impact properties were significantly decreased
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