Advantages and disadvantages of semi-continuous casting method

The quality of magnesium alloy ingot is closely related to the casting methods. The casting methods of magnesium alloy include iron mold casting, water cooling mold casting and semi-continuous casting.

Iron and water - cooled casting methods are obsolete, ingot quality and low production efficiency, has been rarely used. At present, semi - continuous casting is widely used in industrial production. Since the semi-continuous casting method was adopted, the quality of magnesium alloy ingot has been greatly improved.

Advantages of semi-continuous casting:

(1) The high crystallization rate improves the ingot's intracrystalline structure, reduces the regional segregation of chemical composition, and improves the mechanical properties of the ingot.

(2) Due to the improvement of the metal casting system, the oxidation inclusion and metal impurities are reduced, and the purity of the metal is improved. The influence of casting equipment on secondary metal impurities in magnesium alloy is much less.

(3) Reasonable crystallization sequence improves the density of the ingot and reduces the looseness in the center of the ingot:

(4) The length of the ingot is increased, and the percentage of geometric waste such as cutting head and cutting tail is relatively reduced:

Mechanization has been realized, working conditions have been improved, and labor productivity has been raised.

The main disadvantages of semi-continuous casting are:

(1) The increase of crystallization rate in the ingot causes greater internal stress, which increases the crack tendency.

(2) Due to the increase of crystallization rate, for the individual components with small diffusion coefficient, large ingot segregation is caused, so some alloy ingot need to undergo long-term microstructure homogenization treatment C

(3) Because of the high crystallization rate, the temperature gradient in the liquid cavity is large, which is not conducive to the metal intermediate compound particles grow too large, but it makes it easy to produce.