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What are the reasons for the porosity of copper castings?
First of all, in the production of copper castings, the relatively common defects and their causes are analyzed and the prevention methods are as follows. The phenomenon of air holes in copper castings is actually because the alloy liquid suction will be more serious, in addition, in fact, it is important to pay attention to the casting temperature is actually relatively high, in addition, it is because the sand moisture, clay or fine sand content in copper castings is relatively high.
In addition, it is because the copper casting is too solid and its poor air permeability, that is, it is easier to produce the phenomenon of air holes. Furthermore, if the oil sand is relatively high in oil, and the molding sand or core is not dried, moreover, when it faces the pouring system design is not appropriate, or the improper operation or air is involved in the pouring, it will appear the phenomenon of air holes.
Of course, the phenomenon of air holes on copper castings is also caused by water absorption of the casting bag, rust on the surface of the cold iron, relatively damp or the phenomenon of dressing shedding, and also because the metal type oil is too much and the metal mold temperature is too high or too low. Poor ventilation is also due to the blockage of the air outlet or insufficient number of the phenomenon of air holes.
When there are pores on copper casting, we should pay attention to strictly control the charge and molding material composition, especially pay attention to the control of its moisture content, moreover, in terms of itself, that is, it should be noted that it must be improved design, leave enough air outlet.
On the face of the copper casting, the phenomenon of pores, dry type itself, that is, to pay attention to bake, then, that is, to pay attention to have is to control the pouring temperature, and the process of copper casting can not stop, which is to pay attention that liquid column time should be shorter, cleaning and drying for cold iron will.