Sand castings mean the metal castings produced by sand molds. There are many types of sand castings, such as gray iron sand castings, ductile iron sand castings, steel sand castings and aluminum sand castings etc.
There are many types of sands that can be used for sand casting process, including green sand, resin sand, pre-coated resin sand, water glass dry sand etc. Accordingly, the sand casting processes include floor molding, automatic molding and shell molding process.
In the total metal casting output in the whole world, 60% to 70% of metal castings are sand castings. Their unit weight could from dozens of gram to dozens of tons, and their dimensions could be from dozens of millimeters to several meters. Moreover, according to the castings produced by other casting processes, sand castings are the cheapest and have very high production rate.
However, sand castings have many defects, such as sand holes, air holes, shrinkage, cracks, uneven materials, deformation etc. These defects are the main disadvantages for sand castings. However, as for the sand castings made by shell molding process, their defects are very few. So, more and more clients have required their suppliers to use shell molding process.
For your reference, if your products need high dimensional tolerance for rough castings, then you should use shell molding process, although this process is more costly then others.
If your products are large, such as from 1 meter to 2 meter long, from 100 kg to 2 tons, then you should use the resin sand casting process.
If your products are larger than 2 tons, such as the dryer cylinder for paper machinery, then you still need to use the green sand casting process.
If you need very high production rate, such as the automotive parts, then you should use the automatic molding line.
It is easy to find the metal foundries for producing sand castings in China, however, the technical levels have large difference between them. According to my years working experience in Dandong Foundry, I think it is really not an easy word to produce qualified sand castings.
All of the following products were sand castings.
For the whole article, please check Dandong Foundry Blog.