What are the reasons for stainless steel casting air holes?

Stainless steel casting is a casting process with little or no cutting, and it is an excellent technology in the foundry industry. So we all know what is the reason for stainless steel casting air holes?

 

The main reasons for air holes in stainless steel casting are as follows:

 

1. The air permeability of the coating is poor or the negative pressure is insufficient, and the air permeability of the filling sand is poor, so the gas and residue in the mold cavity can not be discharged in time, and pores are formed under the filling pressure.

 

2. The pouring speed is too slow to fill the sprue cup, expose the sprue, get involved in the air, inhale the slag, and form wrapped pores and slag holes.

 

3. A large number of gases and residues produced by the gasification and decomposition of the foam model can not be discharged from the casting in time, and the dry sand filled with foam and coating layer is not dry, surrounded by the high temperature of liquid alloy. the invasion of a large amount of hydrogen and oxygen into the casting is the main reason for the formation of pores.

 

4. The joint between the sprue cup and the sprue and the gating system is not well sealed, especially the connection between the sprue and the sprue cup, which can be calculated and explained by Bernoulli equation.

 

The stainless steel casting is due to the unreasonable design of the gating system, the mold filling speed of the liquid metal is faster than that of foam gasification and gas discharge, and the decomposition hole of smoke black on the inner wall is formed in the liquid metal.

 

The main causes of air holes in stainless steel casting are mainly caused by the above reasons. When there are gas hole problems in our stainless steel casting, we all need to solve these problems in time.