How to prevent deformation in investment casting?
The common deformation problem in investment casting is caused by forging stress, and the main cause of deformation is thermal stress.
The thin thickness of investment casting structure is not uniform, resulting in inconsistent cooling shrinkage of each component during rapid cooling, residual tensile stress (thick wall tube and inner layer) and residual compressive stress (thick wall and outer layer). In the stress state, the precision casting attempts to transition from this unstable state to a stable state, so that it can automatically deform and reduce the internal stress.
Now let's understand the factors that are not easy to deform in investment casting:
First, the structural design of precision castings is not scientific and the wall thickness is uneven.
Poor cooling effect and uneven cooling shrinkage. Therefore, how to avoid or reduce the technical problems of deformation in investment casting by taking effective measures? The main points are as follows.
1. Improve the pouring system equipment for setting.
2. Change the structure to make it as symmetrical as possible and change the wall thickness as slowly as possible.
3. Change the cooling mode to make each position cool as evenly as possible.
4. Investment casting can improve the structure or add reinforcement plates, and strengthen the production process.
5. Set the position of the inner gate scientifically, reasonably and selectively, reduce the different temperature difference of each part, and avoid the feeding system equipment when it is folded, which is a mutual development problem with the precision casting.