In a sand casting foundry there are broadly two reasons for rejection of the casting — metal and sand — each of which has a large number of internal variables.
The testing process is divided into four stages: sampling of the bulk material, sample sand preparation, specimen preparation and testing.
The basic tests measure the following parameters: wet tensile strength, cone jolt, mouldability, friability, moisture content, permeability, green compression strength, compactibility, loss on ignition, volatiles content, grain size & distribution, dust (dead clay) content, and active clay content, impact strength .
Each of these tests can lead you to obtain specific characteristics of sand which can be crucial to the quality of casting.
Green sand properties cannot be standardized for all foundries and castings as such, yet place to place and job to job the specifications can be set to maintain minimal amount of rejection.