What measures can be taken against the deformation of precision castings

During the manufacturing process, castings will deform due to problems such as hardware facilities, management, casting cooling, correction, etc. So, how should we deal with deformation of castings? Casting deformation is divided into micro self-deformation, casting expansion deformation and warping deformation. Micro deformation : Among alloy materials, gray iron is prone to micro-deformation.

After gray iron shakeout cleaning, the residual stress is mainly residual stress. In addition to residual stresses such as cold cracks and casting deformation, residual stress is also the main cause of trace self-deformation. Even if the residual stress does not exceed the yield strength of the material, gray cast iron Microplastic deformation, that is, micro-deformation, will slowly occur over a sustained period of time. Expansion deformation: The reason for its formation is that the sand core or sand at the opening hinders the shrinkage of the casting, causing plastic deformation of the free structural part of the casting opening, resulting in flaring deformation defects.

Warping deformation:

After sand cleaning, two ends, one end and even the outside of the casting are warped, causing the middle part of the casting to be dented, resulting in uneven casting, which is called warping deformation. The main reason is: during the cooling process, due to the uneven thickness or thickness of the casting, there is a temperature difference. The cooling rates of each part of the casting are different and the plastic deformation is uneven, resulting in warping deformation.

In response to the deformation of precision castings, this article proposes 4 measures:

1. Before waxing, first put the mold into the waxing room until the temperature of the mold is the same as that of the waxing room, and then start waxing; as for the back shell, the temperature of the wax part does not need to be increased because there is no control or direct listing in the waxing room room.

2. After the wax pieces come out, mainly check whether the mold is deformed or have other defects during operation; the wax pieces should be placed neatly and uniformly to avoid overlapping and hanging; after shipment, it is recommended to use inspection as much as possible to improve the detection speed and accuracy. According to a certain Periodic calibration.

3. After opening the furnace, when the temperature of the modules is still very high, overlap should be avoided and placed regularly to make the deformation direction consistent to facilitate correction of the fashion clip.

4. Tools for correcting castings should be made of hard materials, the surface should be wear-resistant, and the tonnage of the press or punch should be reasonably calculated to avoid equipment waste or insufficient power.

Precision castings have a great impact on the performance of mechanical products. Poor quality of precision castings will seriously affect the service life of mechanical products. Once deformation of precision castings is found, it should be corrected in time to avoid affecting the performance of precision castings.