The Rockwell scale is a hardness scale based on the indentation hardness of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload. There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, where A is the scale letter.
When testing metals, indentation hardness correlates linearly with tensile strength. This important relation permits economically important nondestructive testing of bulk metal deliveries with lightweight, even portable equipment, such as hand-held Rockwell hardness testers.
Read more about Rockwell Scale: History, Operation, Scales and Values, Standards
Famous quotes containing the word scale:
“That age will be rich indeed when those relics which we call Classics, and the still older and more than classic but even less known Scriptures of the nations, shall have still further accumulated, when the Vaticans shall be filled with Vedas and Zendavestas and Bibles, with Homers and Dantes and Shakespeares, and all the centuries to come shall have successively deposited their trophies in the forum of the world. By such a pile we may hope to scale heaven at last.”
—Henry David Thoreau (1817–1862)