Shrinkage is one of the common problems for steel castings in China. There're certain rules on shrinking percentage of steel castings.
1. If steel castings are packed tightly, the shrinking percentage will be small during solidification of the castings. So, during steel investment casting process, we will bury the steel castings inside the sands to keep the surface tightly pressed.
2. Shrinking percentage of steel castings with thin wall thickness is smaller than the castings with thick wall thickness.
3. Shrinking percentage of big size steel castings is smaller than the small size steel castings.
4. The longer time the steel castings kept in mold after casting, the smaller the shrinking percentage. So, usually the castings will be kept inside the sand shell.
5. Shrinking percentage of complex structure steel castings is smaller than stee castings with simple structure.
6. Shrinking percentage on different section of one part is also difficult in different situation.
7. Shrinking happens inside the solid section of the steel castings. This might cause the oversize problems of the slot between two solid sections of steel castings.
Besides the above rules, lots of factors will affect the shrinking percentage of the steel castings, such as the casting processes,casting systems, etc. To limit the effect of shrinking and improve quality of steel castings, we have to be more careful on casting,technics chosen, casting process controlling, etc.
Our investment casting foundry is always doing our best to improve the shrinking defects on steel castings. If you have RFQs for steel castings, please contact us.