Stanley P. Rockwell invented the Rockwell hardness test.
He was a metallurgist for a large ball bearing company and he wanted a fast non-destructive way to determine if the heat treatment process they were using on the bearing races was successful. The only hardness tests he had available at time were Vickers, Brinell and Scleroscope. The Vickers test was too time consuming, Brinell indents were too big for his parts and the Scleroscope was difficult to use, especially on his small parts
To satisfy his needs he invented the Rockwell test method. This simple sequence of test force application proved to be a major advance in the world of hardness testing. It enabled the user to perform an accurate hardness test on a variety of sized parts in just a few seconds.
There are two types of Rockwell Tests:
- Rockwell: the minor load is 10 kgf, the major load is 60, 100 or 150 kgf.
- Superficial Rockwell: the minor load is 3 kgf and major loads are 15, 30, or 45 kgf.
In both tests, the indenter may be either a diamond cone or steel ball, depending on the characteristics of the material being tested.