1 casting strain
① Along the opening direction, the surface of the casting shows a line like scratch trace with a certain depth, even the whole surface is pulled seriously; ② the liquid metal adheres to the surface of the mold, resulting in the lack of material on the surface of the casting.
① There is damage on the surface of mold cavity; ② there is no inclination or too small inclination in the direction of mold exit; ③ there is imbalance in ejection; ④ the mold is loose; ⑤ the casting temperature is too high or too low, and the mold temperature is too high, resulting in the adhesion of alloy liquid; ⑥ the use effect of mold release agent is not good: ⑦ the iron content of aluminum alloy is lower than 0.8%; ⑧ the cooling time is too long or too short.
(3) Treatment method:
① Repair the surface damage of the mold; ② correct the inclination to improve the surface finish of the mold; ③ adjust the ejector rod to balance the jacking force; ④ fasten the mold; ⑤ control the reasonable casting temperature and mold temperature 180-250. ; ⑥ change release agent: ⑦ adjust the iron content of aluminum alloy; ⑧ adjust the cooling time; ⑨ modify the inner gate and change the direction of aluminum liquid.
2 casting bubble
On the surface of the casting, there are cavities under the surface of rice grain
① The filling degree of the alloy liquid in the pressure chamber is too low, so it is easy to produce air entrainment and injection speed is too high; ② the mold exhaust is poor; ③ the molten liquid is not degassed and the melting temperature is too high; ④ the mold temperature is too high, the metal solidification time is not enough and the strength is not enough, and the casting is ejected too early, so the pressure gas expands; ⑤ too much release agent; ⑥ the inner gate is not opened well, and the filling direction is connected.
(3) Treatment method
① Change the diameter of the pressure chamber to improve the fullness of the liquid metal; ② extend the injection time, reduce the injection speed in the first stage, and change the switching point between low-speed and high-speed injection; ③ reduce the mold temperature and maintain the heat balance; ④ add the exhaust tank and overflow tank to fully exhaust the gas and timely remove the oil and waste on the exhaust tank; ⑤ adjust the smelting process and carry out the degassing treatment; ⑥ appropriately extend the mold retention time : ⑦ reduce the amount of mold release agent.
3 casting crack
① There are linear or wavy lines on the surface of the casting, which are narrow and long, and tend to develop under the action of external force; ② the metal at the cold crack is not oxidized; ③ the metal at the hot crack is oxidized.
① The content of iron in the alloy is too high or the content of silicon is too high; ② the content of harmful impurities in the cauldron is too high, which reduces the plasticity of the alloy; ③ the content of zinc in the aluminum silicon copper alloy is too high or the content of copper is too low; ④ the overall temperature of the mold, especially the cavity is too low; ⑤ the shrinkage is blocked where the thickness and thickness of the casting have dramatic changes, and the sharp angle position forms the stress; ⑥ the retention time of the mold is too long, and the stress is large; ⑦ the ejection time Uneven stress.
(3) Treatment method:
① In some cases, pure aluminum ingot can be added to the alloy to reduce the magnesium content of the alloy or aluminum silicon intermediate alloy can be added to the alloy to increase the silicon content; ② change the casting structure, add angle, change the inclination of the die and reduce the wall thickness difference; ③ change or increase the ejection position to make the ejection force uniform; ④ shorten the time of mold opening and core pulling to improve the mold temperature and keep the mold hot Balance.