Every material that exists has varying levels of hardness. Diamond happens to be the hardest of all known materials for instance. Talc, on the other hand, is on the softer side.
But what does hardness actually mean? Despite popular conception, or rather misconception, it certainly does not indicate toughness of a material or substance. Diamond, which is the hardest, would most certainly crack if hit with a hammer. Steel, on the other hand, would not.
To clear all confusions, hardness indicates the ability of an object to avoid indentation when force is applied. In simpler terms, objects with high resistance to scratches are considered hard (diamond being one of them) while those that are more easily scratched are not considered to be that hard. The Rockwell and Brinell Tests are used to measure the hardness of substances.
When to use the Brinell Test?
When it comes to substances that have a rough surface, the Brinell tests should be used due to the fact that it can be relatively destructive and smooth surfaces would suffer.
It is also used in cases where any other test would not be able to gain satisfactory results. With the comparatively big indenter, the Brinell Test is ideal for specific substances or metallic objects that require a large indenter.
It, however, tends to be rather slow and cumbersome when compared to similar tests and that should be kept in mind for those who have time restrictions put in place for the testing process.
When to use the Rockwell Test?
When it comes to those who lack much experience in testing hardness, the Rockwell Test should be a primary choice owing to the fact that it is a relatively easy test to conduct. Not to mention, it all but eliminates mechanical errors and produces the most accurate results.
The Rockwell Test is ideal for testing the hardness of all sorts of materials or substances. That includes rather hard substances like hardened steel or other hard metals.
This gives more reason for testers to use this test and that is exactly what they do as the Rockwell Test happens to be the most common method for hardness testing.
If preservation of the test material happens to be a priority, then Rockwell Test is perfect as it avoids as much damage to the surface as possible while getting accurate results.