What causes the shrinkage cavity of silica sol precision casting?

The most basic cause of shrinkage cavity is that when the aluminum alloy shrinks and solidifies in the liquid, the silica sol precision casting factory finds that a certain position of the casting (usually the hot spot where the final solidification is finally solidified) cannot obtain liquid metal feeding in time, so A shrinkage cavity is created at that point.

For carbide aluminum alloys or aluminum alloys with a narrow solidification temperature range, concentrated shrinkage cavities are prone to occur in castings. When the alloy composition is on schedule, the shrinkage cavity is usually caused by uneven thickness of the casting, too many hot joints, too large, unreasonable design of the control system of the pouring riser, which is not conducive to sequential solidification, so that the hot joints of the silica sol precision casting parts cannot be Get filled with molten metal. Or the pouring temperature is too high.

Countermeasures to avoid:

1: Improve the structure of castings to ensure uniform thickness, reduce thermal joints, or make thickness changes conducive to orderly solidification.

2: Effectively set the riser system to cause the order to freeze. More consideration should be given to the pouring riser system of complex parts with multiple hot spots.

3: Effectively assemble the modules, so that there is a certain distance under the silica sol precision casting parts, so as to avoid the difficulty of partial heat dissipation.

4: The pouring temperature of the shell and molten metal should be suitable, and the pouring temperature should not be too high

5: When pouring, ensure that the sprue and riser are filled with molten metal, and add heating agent and thermal insulation agent to the sprue cup and riser

6: Improve smelting and processing technology, reduce waste gas and metal oxides in molten metal, and improve circulation and feeding level.