What does the B scale refer to in hardness testing?

In hardness testing, the B scale refers specifically to a method that utilizes a ball indenter for testing the hardness of materials. The B scale is commonly associated with the Rockwell hardness test, one of the widely used hardness testing methods. This scale is primarily designed for softer materials, such as metals and polymers, allowing for effective hardness measurement without perturbing the material excessively.

The rationale behind using a ball indenter, typically made from hard steel or carbide, is that it can better conform to the surface of the material being tested, providing a reliable measure of hardness through the depth of the indentation created. The depth is measured under a specific load, and the value obtained on the B scale reflects the material's resistance to deformation under that load.

Using a ball indenter is advantageous for achieving consistent and repeatable results across various material types, particularly those with lower hardness levels. The option emphasizing no indentation, or the use of other shapes like a cone or flat indenter, does not relate to the B scale in hardness testing, as these concepts pertain to different testing methodologies or scales.