Industry News
Characteristics of zinc alloy
2020-05-10
1. Relatively large proportion.
2. The casting performance is good. It can be used to cast precision parts with complex shape and thin wall. The surface of the casting is smooth.
3. Surface treatment: electroplating, spraying, painting, polishing, grinding, etc.
4. During melting and die casting, it does not absorb iron, corrode the die and stick the die.
5. It has good mechanical properties and wear resistance at room temperature.
6. Low melting point, melting at 385 ℃, easy to die-casting.
Problems to be noted during use:
1. Poor corrosion resistance. When the impurity elements lead, cadmium and tin in the alloy exceed the standard, the castings will be deformed due to aging, which shows as volume expansion, significant decrease in mechanical properties, especially plasticity, long time and even fracture.
The solubility of lead, tin and cadmium in zinc alloy is very small, so they concentrate on the grain boundary and become the cathode, and the aluminum rich solid solution becomes the anode. In the presence of water vapor (electrolyte), it promotes the electrochemical corrosion between grains. Die castings are aged due to intergranular corrosion.
2. Time effect
The structure of zinc alloy is mainly composed of zinc rich solid solution containing Al and Cu and aluminum rich solid solution containing Zn. Their solubility decreases with the decrease of temperature. However, due to the rapid solidification rate of die casting, the solubility of solid solution is greatly saturated at room temperature. After a certain period of time, the supersaturation will be relieved gradually, and the shape and size of the casting will change slightly.
3. Zinc alloy die casting should not be used in high temperature and low temperature (below 0 ℃). Zinc alloy has good mechanical properties at room temperature. However, the tensile strength at high temperature and the impact property at low temperature decreased significantly.
2. The casting performance is good. It can be used to cast precision parts with complex shape and thin wall. The surface of the casting is smooth.
3. Surface treatment: electroplating, spraying, painting, polishing, grinding, etc.
4. During melting and die casting, it does not absorb iron, corrode the die and stick the die.
5. It has good mechanical properties and wear resistance at room temperature.
6. Low melting point, melting at 385 ℃, easy to die-casting.
Problems to be noted during use:
1. Poor corrosion resistance. When the impurity elements lead, cadmium and tin in the alloy exceed the standard, the castings will be deformed due to aging, which shows as volume expansion, significant decrease in mechanical properties, especially plasticity, long time and even fracture.
The solubility of lead, tin and cadmium in zinc alloy is very small, so they concentrate on the grain boundary and become the cathode, and the aluminum rich solid solution becomes the anode. In the presence of water vapor (electrolyte), it promotes the electrochemical corrosion between grains. Die castings are aged due to intergranular corrosion.
2. Time effect
The structure of zinc alloy is mainly composed of zinc rich solid solution containing Al and Cu and aluminum rich solid solution containing Zn. Their solubility decreases with the decrease of temperature. However, due to the rapid solidification rate of die casting, the solubility of solid solution is greatly saturated at room temperature. After a certain period of time, the supersaturation will be relieved gradually, and the shape and size of the casting will change slightly.
3. Zinc alloy die casting should not be used in high temperature and low temperature (below 0 ℃). Zinc alloy has good mechanical properties at room temperature. However, the tensile strength at high temperature and the impact property at low temperature decreased significantly.