Rockwell Hardness Test

A hardness testing method in which a minor load is applied to seat the penetrator into the specimen and hold it in place. Once the penetrator has settled into the specimen, the major load is removed and the Rockwell hardness number is read directly on the dial. Once it has been recorded, the minor load is removed. The type of penetrator chosen for any given test depends on the hardness of the material. 1/8 and 1/16 inch hardened steel ball penetrators are used for softer metals and cone-shaped diamond penetrators are used for harder metals.