Casting is a kind of special casting method with less cutting developed rapidly in modern metal processing technology.
Casting is a process that unifies pressure, speed and time by using three major elements: machine, mould and alloy. It is also a process in which molten metal is filled with mold at high pressure and high speed and crystallized and solidified to form casting. High pressure and high speed are the main characteristics of Casting.The commonly used pressure is tens of mpa, the filling speed (inner gate speed) is about 16~80 m/s, and the time of filling mold cavity with liquid metal is very short, about 0.01~0.2 seconds. It combines the three elements of die casting machine, die-casting mold and alloy organically. At the same time, these technological factors interact with each other. Only by properly selecting and adjusting these factors and making them consistent can we achieve the desired results.
The basic process is: the metal liquid is first filled into the cavity of the mold by low speed or high speed casting, and the mold has a movable cavity surface, which is pressed and forged with the cooling process of the molten metal, thereby eliminating the shrinkage of the blank. Loose defects also cause the internal structure of the blank to reach the forged broken grain. The overall mechanical properties of the blank are significantly improved. In addition, the blank produced by the process has an outer surface finish of 7 (Ra1.6), such as a cold extrusion process or a machined surface, with a metallic luster. Therefore, we call the die-casting forging process the “extreme forming process”, which is a step further than “no cutting, less residual forming process”. Another advantage of the die-casting forging process is that, in addition to producing traditional casting materials, it can also produce deformed alloys and forged alloys to produce highly complex parts. These alloy grades include: hard aluminum super-hard aluminum alloy, wrought aluminum alloy, such as LY11, LY12, 6061, 6063, LYC, LD, etc.) The tensile strength of these materials is nearly twice as high as that of ordinary cast alloys. It is more positive for aluminum alloy automobile wheels, frames and other parts that are expected to be produced with higher strength and impact resistant materials.
Because the products produced by this method have the advantages of high production efficiency, simple process, high tolerance grade of casting, good surface roughness, high mechanical strength, can save a lot of mechanical processing procedures and equipment, and save raw materials, it has become an important part of China's casting industry.