7-Heat Treating - Tool Steels
|The machinist must be able to obtain a quantitative value for material hardness before machining and/or heat treating. Since hardness is the ability to resist deformation a machine that measures the slightest deformation made by a penetrator while under an applied pressure can serve as a gauge. These deformation marks are measured and then compared to a standard to determine a hardness reading.
The Brinell standard is one of the most common hardness scales. It is used primarily for soft materials such as aluminum.
The Rockwell scale (aka :Vickers") is used primarily for harder metals such as post heat treated tool steels.