Which technique is used to measure the hardness of metals?

The Rockwell hardness test is a widely used method for measuring the hardness of metals, making it a valid choice in this context. This technique evaluates hardness by determining the depth of penetration of an indenter under a large load compared to the penetration made by a preload. The Rockwell test is particularly useful for a variety of metals because it provides quick and direct hardness measurements without the need for extensive sample preparation or sophisticated equipment.

While the Vickers hardness test and the Mohs hardness test are also methods used to measure hardness, they have different applications and contexts. The Vickers test is applicable to a wide range of materials, including metals, and uses a diamond pyramid-shaped indenter to assess hardness. The Mohs hardness test, on the other hand, is primarily used for minerals and ranks them relative to each other based on their ability to scratch one another, which is less practical for measuring metallic hardness in industrial or engineering contexts.

Given the specific focus on metals, the Rockwell hardness test is particularly relevant, but it’s important to acknowledge that all three methods mentioned do measure hardness in their respective contexts. However, since the question asks for the technique that is common in measuring hardness specifically for metals, the Rockwell hardness test is highlighted as the most appropriate