Well, forDongguan Precision CastingAs far as the pieces are concerned, what kind of solidification method is used for the sequential and simultaneous solidification methods?

First of all, it depends on the requirements of the casting. If the casting is required to be dense, the principle of sequential solidification shall be adopted; if the requirement of density is not high, then the principle of simultaneous solidification shall be adopted.

Secondly, for alloys that have large solidification shrinkage and do not produce a large amount of crystalline framework that hinders feeding, such as: cast steel, ductile cast iron, etc., tend to be directional solidification; while solidification shrinkage is large, but there is a tendency to produce a crystalline framework that hinders feeding. Alloys that are easy to form dispersed shrinkage, such as tin bronze, or alloys with little solidification shrinkage, such as gray iron, tend to use simultaneous solidification. For castings that are prone to thermal cracking and deformation, the principle of simultaneous solidification can be adopted, while for products with large thickness differences, the principle of sequential solidification should be adopted.

forDongguan Precision CastingCastings or certain parts of castings that can withstand high temperature and high pressure, are not allowed to leak, or are subjected to a lot of force but must be absolutely safe to use; the parts of the castings that are more demanding and need to be processed should be solidified in sequence. Although a certain part of the casting is subjected to large forces, other requirements are not high, and it is not a hot joint; when the wall thickness is uniform, the principle of simultaneous solidification should be adopted. In addition, it can be seen from the above that a casting does not necessarily adopt one solidification method, but can also adopt two solidification methods, according to product requirements. Where the wall thickness is uniform, the principle of simultaneous solidification is adopted, and where the wall thickness differs, the principle of sequential solidification is adopted.

The advantages and disadvantages of the principle of simultaneous solidification and sequential solidification: Simultaneous solidification because the temperature of all parts of the casting is basically the same, the cooling is uniform, the shrinkage stress of the casting is small, and the casting is not prone to deformation and cracks. The disadvantage is that castings with large liquid shrinkage tend to produce axial shrinkage, insufficient density, and reduced plasticity of the casting; the opposite of sequential solidification and simultaneous solidification, the temperature difference of each part of the casting is large, which will cause greater thermal stress, which is easy to cause the casting Deformed or cracked. Moreover, due to the use of the riser, the consumption of the molten metal and the workload of cutting the riser are increased. But the advantage isDongguan Precision CastingThe inner quality is good and dense.