The casting defects of hole steel include pores, shrinkage holes, shrinkage porosity, slag holes, trachoma, iron beans, etc.

stomata
Also known as casting defects caused by air holes, air bubbles and pores. The characteristics of casting pores are: generally round or irregular holes, the inner surface of the hole is smooth, and the color is white or with a layer of old dark color.
The reasons for casting defects are: the charge is damp or corroded; the surface is not clean, the gas such as steam in the furnace; the furnace body and ladle are not dried after repair; the gas in the cavity and the incorrect gating system; the gas is involved in the casting and crystallization The permeability of the device or mud core is poor, etc.

Shrinkage
These are hole casting defects caused by shrinkage. The shrinkage cavity is characterized by irregular shape, roughness in the hole and coarse grains.
The cause of casting defects is that the metal shrinks during the liquid state and solidification process. The main points are as follows: the structural design of the casting is unreasonable; the casting system is improper; the size, quantity and location of the cold iron do not match the actual situation; the chemical composition of the molten iron does not meet the requirements, such as excessive phosphorus content. The pouring temperature is too high, the running speed is too fast, etc.

shrink
Also known as loose, pinhole honeycomb, small hole porous casting defects caused by shrinkage resistance. The characteristics of shrinkage rate are:
Small and disjointed pores.
The grains are coarse and there are obvious meshes between the grains.
Water seepage during hydrostatic test.
casting defects
scum
Slag inclusions, slag bags, dirty eyes, low temperature of molten iron, and improper slag pouring can also cause slag hole casting defects. The characteristics of the slag hole are: the shape of the hole is irregular and not smooth; the whole or part of the hole is filled with slag.
The reasons for casting defects are: insufficient purity of molten iron; poor slag removal effect and poor slag retention effect during pouring; poor slag retention in the gating system, and the gate is not satisfied or cut during pouring.

trachoma
Trachoma is a trachoma casting defect with sand in the middle. Trachoma is characterized by irregular holes, which are filled with molding sand or core sand.
The reasons for casting defects are: damage and peeling of the molding sand when the box is closed. Loose sand or sand blocks in the cavity are not cleaned up. The compactness of the molding sand is poor, and the core is broken during pouring; the pouring system is improperly designed, and the surface coating of the core is poor.

iron beans
Iron beans are holes that hold iron beads. Also known as iron beads, bean eyes, iron bean trachoma, etc. The characteristics of iron beans are: the holes are relatively regular, and the holes contain tiny metal beads. Such casting defects often occur in iron castings.