There are defects in some parts of the casting, which often appear in the thin-walled part, the farthest part from the sprue or the upper part of the casting. The incomplete corners are smooth and bright without sand sticking.
(1) Low pouring temperature, slow pouring speed or intermittent pouring;
(2) The cross-sectional area of the cross sprue and the internal sprue is small;
(3) The content of carbon and silicon in molten iron is too low;
(4) Too much moisture and pulverized coal content in molding sand, large gas generation, or too high mud content, poor permeability;]
(5) The height of sand mold is not enough, and the pressure of molten iron is not enough.
(1) Raise pouring temperature and speed up pouring to prevent intermittent pouring;
(2) Increase the cross-sectional area of the cross sprue and the internal sprue;
(3) Adjust the burden after the furnace and increase the content of carbon and silicon properly;
(4) Strengthen the exhaust in the mold, reduce the amount of pulverized coal and organic matter in the molding sand;
(5) Increase the height of the upper sandbox.