Aluminum alloy die-casting technology development status and trend forecasting
After the 1990s, the die casting industry in China has made a stunning development, has been developed as an emerging industry. At present, aluminum die casting process has become a vehicle forming one of the most widely used technology in the process, accounted for 49% of the molding process in a variety of automotive aluminum alloy.
Existing die-casting enterprise in China around 3000, die-casting production from 266,000 tons in 1995 rose to 870,000 tons in 2005, the annual growth rate of more than 20%, which accounted for all die-casting production in the aluminum die casting / 4 above. Chinese die casting product range was diversified, including automobiles, motorcycles, telecommunications, home appliances, hardware, power tools, the IT, lighting, escalators cascade, toys, lamps, etc.. With the technical level and product development capabilities, the types of die casting products and applications continue to broaden its die-casting equipment, die casting mold and die casting process have undergone tremendous changes. With the invention of the automobile industry development and cold chamber die casting machine, die-casting aluminum alloy die-casting aluminum alloy has been put into commercial production since 1914 has been rapid development.
Divided into low-intensity (such as the Y102) and high-strength (such as the Y112) two die-casting aluminum alloy according to the performance. Industrial applications of cast aluminum alloy of the following series: Al-Si, Al-Mg, Al-Si-Cu, Al-Si-Mg, Al-Si-Cu-Mg, Al-Zn. Improve the mechanical properties of die-casting aluminum alloy is often accompanied by a reduction of the casting process performance, pressure die casting because of its high pressure characteristics of rapid solidification so that this contradiction is more prominent in some respects, it is generally die casting difficult of solution heat treatment, which regulate the improvement of casting aluminum alloy mechanical properties, although the die casting, vacuum die casting is an effective way to improve the mechanical properties, but widespread adoption is still a certain degree of difficulty, so the new die-casting aluminum alloy developed has been conducting. Advanced die-casting technology early in the horizontal cold chamber die casting machine casting process is only one speed Pressure of liquid metal into the mold, the injection speed of only 1m to 2m / s. With this process, casting the internal porosity, loose tissue, soon to improve the two injection, the injection process is decomposed into slow and fast two stage, but the fast speed of 3m / s, later in order to die casting density, increased by one stage pressure increases after the slow and fast, slow shot, fast injection and supercharged three stages, this is the classic three-segment injection. Vacuum die casting method compared with the ordinary die-casting method has the following characteristics: (1), the porosity is greatly reduced; (2) vacuum die casting, high hardness, microstructure and small; (3) vacuum die casting, high mechanical properties. Recently, vacuum die casting in order to pumping gas in addition to cavity-based, there are two main forms: (1) direct exhaust from the mold; (2) set the mold in the vacuum tank pumping. Vacuum die-casting, the design of the exhaust position of the mold and exhaust tract area is essential. Exhaust there is a "critical area", is related to the amount of gas out with the cavity, the pumping time and filling time.