What Are The Causes Of Deformation Of Steel Cast By Heat Treatment?

There are many kinds of heat treatment processes for casting parts, which are generally composed of three stages: heating, insulation and cooling. However, the deformation of casting parts often occurs in the process of hot working. So, what are the causes of deformation of steel castings in heat treatment?

 

 

1. Heating causes deformation. When the foundry is heating large steel castings, if there is residual stress or uneven heating, with the gradual increase in temperature, the yield strength of the steel will gradually decrease, and in the process of heating, the casting will cause deformation.

 

2. Deformation caused by cooling. Because of the cooling difference between the outer edge and the inside of the steel casting, the superposition of the thermal stress and the structural stress of the steel casting in the case of quenching will lead to the deformation of the steel casting more complicated.

 

3. Cold treatment leads to deformation. Cold treatment promotes the transformation of martensite in the casting, although the deformation caused by the reduction of temperature is smaller than that caused by quenching, but the stress generated at this time is larger, and the superposition of residual stress and thermal stress will make the casting more prone to cracking.

 

4. Tempering leads to deformation. During the tempering process, the deformation of the workpiece tends to decrease due to the homogenization of the internal stress. But once deformed, it's hard to correct.

 

5. Repeated quenching leads to deformation. Under normal circumstances, repeated quenching of the workpiece without intermediate annealing after the completion of a quench will increase the deformation.

 

 

There are many reasons for the deformation of steel casting heat treatment, steel casting manufacturers should judge according to the actual situation, so as to find a reasonable way to solve.