Why does pore trachoma occur in copper casting?

2019-06-05 15:41:55

What is the reason for producing blowhole trachoma in cast copper and aluminium parts? Many people will ask this question, but I think this problem is caused by poor control in the operation of the whole casting process.


Why do the cast copper and aluminium parts have large and small pores and trachoma in varying degrees after processing or polishing?


First, when pouring, metal shrinks from liquid to solid, so riser feeding is needed, and shrinkage will occur when the feeding is insufficient or the position is not right.


Secondly, the non-drying of sand moulds is the main cause of bubbles, especially for copper parts and large workpieces with thick wall thickness.


Thirdly, if the material is not good, small black dot-like shrinkage will appear.


Fourth, of course, degassing is also very important.