The method in which liquid aluminum alloy flows from the pressure chamber into the mold cavity at a very fast speed under high temperature and high pressure, and forms a casting after cooling is called aluminum alloy die casting. However, in the production process, the molding of aluminum alloy die castings will be affected by many factors, and some problems and defects will occur, so we must pay attention to some details.
In the actual production and manufacturing of aluminum alloy die castings, castings will have defects such as pores and bubbles. Porosity is mainly a smooth hole in the center of the surface part or the thick wall, which is mainly caused by poor exhaust or solution encapsulation. Bubbles are holes under the skin of the casting.
To prevent the formation of pores in aluminum alloy die castings, we should carefully clean the equipment before production to ensure that the charge is clean and dry, and some degassing agents can also be added. During the production process, we should also pay attention to exhaust at all times, choose scientific and reasonable die casting process indicators and design reasonable molds. We can also expand the gate in the mold, control the flow rate of the solution, and reduce the filling speed. Or we can also reduce the casting temperature, speed and pressure to reduce the problem of bubbles in the process of aluminum alloy casting.
Surface cracks in aluminum alloy die castings are caused by improper operation of the staff during the production process, such as concave stripes on the surface of the casting. Improper handling produces scratches and other surface cracks.
Therefore, in the production process of aluminum alloy die castings, we should pay attention to mold temperature control and reasonable use of release agents, control the flow rate of the solution, ensure mold cleanliness and other issues. We must pay attention to being careful and careful when working.
During the production process, holes such as uneven surfaces and roughness may appear. These problems mainly occur because we do not compensate enough in the castings during condensation, the wall of the parts is too thick, the casting temperature is too high, and the die-casting process is unscientific, which will cause shrinkage holes in the castings.
In order to reduce the occurrence of these problems, we can improve the structure of the parts in time, try to ensure that the thickness of the parts is the same, plan point cooling for the thicker parts, increase the overflow tank capacity, and improve the casting system. For molds with higher temperatures, we should adopt necessary cooling methods. Add 0.15%~0.2% of metallic iron or other grain refiners into the alloy liquid, change to an alloy type with low volume shrinkage and linear shrinkage, or adjust the alloy liquid to reduce the shrinkage of the casting.
