Alloy die casting is a metal casting process characterized by the use of a mold to apply high pressure to the molten metal. The mold is usually made of a stronger alloy, a process somewhat similar to injection molding. Most die-cast castings are iron-free, such as zinc, copper, aluminum, magnesium, lead, tin, lead-tin alloys and their alloys. Depending on the type of die casting, it is necessary to use a cold chamber die casting machine or a hot chamber die casting machine.

The essence of alloy die casting is that liquid or semi-liquid metal fills the die casting cavity at high speed under the action of high pressure, and then forms and solidifies under pressure to obtain castings. High-pressure type-filled die-casting and high-speed type-filled die-casting are the two major characteristics of die-casting, and its common injection pressure ranges from thousands to tens of thousands of kPa, and even as high as 2105kPa. The filling speed is about 10~50m/s, and sometimes even more than 100m/s. The filling time is short, generally in the range of 0.01~0.2s. Compared with other casting methods, alloy die casting has the following three advantages:

1. Good product quality. The dimensional accuracy of castings is high, generally equivalent to 6~7 grades, and even up to 4 grades; The surface finish is good, generally equivalent to 5~8 grades; And the strength is generally 25-30% higher than that of sand casting, but the elongation is reduced by about 70%. Dimensional stability, good interchangeability, can die-cast thin-walled complex castings. For example, at present, aluminum alloy castings can reach 0.5 mm; the wall thickness of zinc alloy die castings can reach 0.3mm; the spacing is 0.75 mm; and the casting aperture is 0.7mm. 2. High production efficiency. Machine productivity is very high, for example, domestic horizontal cold air die casting machine can die casting 600 ~ 700 times every eight hours, small hot chamber die casting machine can die casting 3000 ~ 7000 times every eight hours. The die-casting mold has a long service life, which can reach hundreds of thousands or even millions of times, and is easy to realize mechanization and automation. 3. Good economic effect. Due to the dimensional accuracy of die castings and the smoothness of the surface, they are generally used directly, not machining, which not only improves the utilization rate of metals, but also reduces a lot of processing equipment and man-hours; Combination die casting can be used for other metal or non-metallic materials, saving not only assembly time, but also metal.

Application range and development trend of alloy die casting: alloy die casting is one of the advanced metal forming methods, which is an effective way to achieve less chips and no chips, and is widely used and develops rapidly. The size and weight of the casting depends on the power of the die casting machine, as the power of the die casting machine is increasing, the size of the casting can be from a few millimeters to 1 ~ 2m. The weight varies from a few grams to tens of kilograms. Alloy die casting is no longer limited to the automotive industry and instrument industry, but gradually expanded to other industrial sectors, such as defense industry, machine tool industry, agricultural machinery, electronic industry, medical equipment, computers, clocks, cameras and daily hardware, etc., including: bathroom accessories, furniture accessories, auto parts, lighting parts, razors, toys, tie clips, electrical and electronic parts, belt buckles and cases. In terms of die casting technology, new technologies such as vacuum die casting, oxygenated die casting, fast dense die casting and the application of soluble cores have emerged.