Process characteristics of semi-solid casting

During the solidification process of liquid metal, strong agitation is carried out to break the dendrite network skeleton easily formed by ordinary casting to form a dispersed granular structure, so as to make a semi-solid metal liquid, and then die cast it into billets or castings. This is semi-solid die casting, and Japan has set up a metal semi-solid processing development and research company. The application of semi-solid casting technology has gradually become a field of development in advanced industrial countries, and is called a new generation of emerging metal forming technology in the century by experts and scholars.

After years of research and development, at present, aluminum and magnesium alloy semi-solid casting technology has entered the growth period of industrial application in Western developed countries. Foreign development and production show that in the automotive industry, car, light vehicle steering knuckle, pump body, steering gear shell, valve body, some suspension support parts and wheels such as high strength, high density, high reliability requirements of castings, the use of semi-solid casting technology can achieve low-cost high-yield and high quality products. So we can not see that semi-solid die casting is a very mature technology.

Compared with ordinary liquid casting, semi-solid casting has many obvious characteristics: the solidification shrinkage of castings is reduced, the size accuracy of castings is high, the appearance quality is good, the machining amount is reduced, and even no machining allowance castings can be obtained; The columnar crystals and coarse dendrites in conventional castings are eliminated, and the castings have fine structure, compact, uniform distribution, and no macrosegregation. The metal filling is smooth, no turbulence, no splash, and the filling temperature is low, extending the life of the mold; Simplify the casting process, reduce energy consumption, improve working conditions, due to the fast solidification speed, high productivity; Improve the mechanical properties of castings.