Defects of die casting:
1、 Streaks / streaks.
Features: the surface of the casting presents the smooth lines of local depression which are consistent with the flow direction of the liquid metal can be felt by hand. This defect has no development direction can be removed by polishing.
1. The trace left by two streams of metal filling the cavity asynchronously.
2. Such defects are easy to occur when the mold temperature is lower than 150 ℃ for zinc alloy 180 ℃ for aluminum alloy.
3. Filling speed is too high.
4. Too much paint.
1. Adjust the cross-sectional area position of the inner gate.
2. Adjust mold temperature increase overflow tank.
3. Adjust the filling speed to change the flow pattern of the cavity filled with liquid metal.
4. The coating is thin uniform.
2、 Cold water mark / cold joint (butt joint), water mark.
Features: the gap formed by the butt joint but fusion of the metal flow with low temperature is irregular, with two types of penetration non penetration, has a development trend under the action of external force.
1. The pouring temperature of molten metal is low the mold temperature is low.
2. The alloy composition does meet the standard, the fluidity is poor.
3. The liquid metal is filled in strands has poor fusion.
4. The gate is unreasonable the process is too long.
5. Low filling speed poor exhaust.
6. The specific pressure is low.
1. Raise the pouring temperature mold temperature properly.
2. Change the composition of the alloy improve the fluidity.
3. Improve the pouring system, increase the speed of the inner gate improve the filling conditions.
4. Improve discharge conditions increase overflow flow.
5. Improve the injection speed exhaust conditions.
6. Increase specific pressure