Process for optimizing porosity defects in aluminum alloy die castings
With the need for lightweight, energy saving and emission reduction, aluminum alloys are increasingly used in transportation fields such as aerospace, automobiles and ships.
With the need for lightweight, energy saving and emission reduction, aluminum alloys are increasingly used in transportation fields such as aerospace, automobiles and ships. The use of lightweight materials to manufacture auto parts is an effective way to reduce the weight of the car. Aluminum alloy die casting has become a good choice due to its excellent material properties, convenient molding and light weight. The application of aluminum alloy die castings in automobiles mainly focuses on housing parts, engine parts and other components.
1. Stomatal shape of aluminum alloy die castings
Porosity is a spherical hole defect with smooth inner surface in die castings. Generally, the gas precipitated in the form of bubbles during the cooling and solidification process is too late to discharge the liquid level and remains in the die casting to form. Small and scattered pores, the so-called pinholes, are formed during the solidification process of the casting before it can be discharged, and most of them are circular and uneven. Thick and large sections of the casting and parts with a slow cooling rate often appear.
2. Technology to optimize stomata
2.1 Dual-channel high vacuum technology
Through the application of the new dual-channel high vacuum technology, the gas content in the mold cavity and the pressure chamber is reduced to make it close to a vacuum state, and the application of purification and degassing technology is increased to reduce the gas content of the melt, thereby reducing the internal porosity of the die casting. produce.
2.2 Optimization of spraying process
Optimize the spraying process, reduce the residual amount of mold release agent by shortening the spraying time, improving the nozzle direction, and prolonging the blowing time, which can effectively avoid the intensive pinhole defects caused by the instantaneous vaporization of molten aluminum and moisture.
2.3 Methods to improve the porosity of aluminum alloy die castings
Reasonable high-speed switching point selection has a great impact on the internal quality of die castings. Colleagues improve the mold gating system according to the internal quality requirements of the product, which has positive significance for improving the quality of die castings.