[knowledge] Qingdao die casting die casting defects, there is the largest number of stomata.
Die casting stomatal characteristics. Have a smooth surface, the shape is round or oval. The forms can be in die casting surface, or subcutaneous pinhole, and possibly also in castings.
(1) gas source
1) alloy liquid precipitation in gas - a related to raw materials and smelting process of B
2) die casting process involved in gas - - A and die casting process parameters and die structure for B
3) release agent produced from the decomposition of gas - - A and coating characteristics of B and spraying process
(2) gas analysis of raw materials and smelting process
The gas in the liquid aluminum is mainly hydrogen, accounting for about 85% of the total gas.
The melting temperature is high, the hydrogen solubility in molten aluminium is higher, but the solubility in the solid aluminium is very low, so in the process of solidification, the hydrogen evolution porosity formation.