The casting defect is the main reason to cause the reject, and it is a serious threat to the casting quality. What are the common casting defects of castings? There are many kinds of casting defects; The defects that can be repaired are generally air holes, sand holes, slag holes (slag inclusion), shrinkage cavities, shrinkage porosity, cracks and so on. Today, I will give you a detailed description of the appearance characteristics of casting defects, as well as the causes, the purpose is to prevent, reduce and eliminate casting defects, effectively do a good job in casting.
What are the common defects of castings and their causes?
1. Air holes
One of the reasons for air holes is that there is too much water in the modeling material or contains a large number of gas substances; Second, the permeability of molding sand and core sand is poor; Third, the casting speed is too fast.
2. Sand holes
The causes of sand holes are that the strength of molding sand is not enough, the compactness of molding sand is not enough, and the pouring speed is too fast.
3. Shrinkage cavities
Shrinkage cavities are caused by the poor feeding of the castings during solidification.
4. Adhesive Sand
The cause of adhesive sand is the poor fire resistance of the molding sand or the high pouring temperature.
The causes of cracks are the large difference of wall thickness of castings, improper gating system, and the difference between sand mold and core.
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The ceramic foundry sand produced by Luoyang Ruiyu has the advantage of low thermal expansion coefficient, and its performance can be comparable to that of zircon sand; Casting expansion defects will not occur when using ceramic foundry sand to prepare molding sand. It is a neutral material, which can be used with acid or alkali binder. It also has a special advantage of not broken, no dust; The ceramic foundry sand has high cost performance and can be recycled repeatedly for hundreds of time.