压铸产品（Die-casting products）.doc

压铸产品（Die-casting products） Defects in die castings: 1. Flow marks Other name: stripe. Features: the surface of the casting is in accordance with the direction of the flow of liquid metal, and the local felt and smooth lines are felt by hand. This defect has no direction and can be removed by polishing. Causes, elimination measures 1, two strands of metal flow out of sync, filling the cavity and leaving traces. 2, mold temperature is low, such as zinc alloy mold temperature is lower than 150 degrees, aluminum alloy mold temperature below 180 degrees, are easy to produce such defects. 3, filling speed is too high. 4, too much paint. 1. Adjust the sectional area or location of the gate. 2, adjust the mold temperature, increase overflow tank. 3, adjust the filling speed properly to change the flow pattern of the cavity filled with metal liquid. 4. The coating is thin and uniform. Two, cold separation Other name: cold junction (butt joint). Features: the lower temperature of the metal flow to each other, but not fusion, and the gap appears irregular linear, there are two kinds of penetrating and non penetrating, under the influence of external force, there is a trend of development. Causes, elimination measures 1 、 pouring temperature of metal liquid is low or die temperature is low. 2, alloy composition does not meet the standard, poor liquidity. 3, the liquid metal split filling, poor fusion. 4, gate unreasonable, the process is too long. 5 、 low filling speed or bad exhaust. 6, lower than the pressure. 1, appropriately increase pouring temperature and mold temperature. 2, change alloy composition, improve flowability. 3, improve the pouring system, improve the filling conditions. 4, improve discharge conditions and increase discharge. 5, improve the injection speed, improve exhaust conditions. 6, increase the specific pressure Three, abrade Other name: tension, stretch mark, mould sticking mark. Features: along the direction of the release, due to metal adhesion, the