The defects of the iron casting includes the warping of both ends of the iron casting, the middle arch (convex) or the twisting warping. This is due to the fact that the shape and size of the iron castings are not consistent with the drawings.
The defects of iron casting are due to the unreasonable structure design of the casting, and because of the difference of the thickness of the casting wall, which will make the cooling rate of the casting uneven, and then affect the normal shrinkage of the casting.
The improper setting position of the sprue（flash groove）on the iron casting will also lead to defects. The distance between the sprue or flash groove and raised part of the casting is relatively close, and the amount of mold thickness is very little, which will hinder the normal shrinkage of the casting itself.
The defect of iron casting is that the core bone has little mold thickness or poor deformability of core sand, and the normal shrinkage of the casting itself will be blocked after pouring. Mold dismantling too early will cause the casting to be cooling unevenly, affecting the normal shrinkage of the iron casting, and sometimes causing the casting to crack.