Which indentation tool is used in the Rockwell B test?

The Rockwell B test specifically employs a 1.6 mm ball indenter for measuring hardness. This test is utilized primarily for softer materials, such as non-ferrous metals and some plastics, where the use of a ball indenter allows for accurate measurements while minimizing the risk of damage to the material being tested.

The choice of a 1.6 mm ball is particularly significant because the diameter of the ball provides a larger contact area compared to other indenters, which is essential for softer materials. This helps to ensure that the load applied during the test results in a suitable depth of indentation that effectively reflects the hardness of the material.

Using a diamond cone, square pyramid, or flat indenter would not be appropriate for the Rockwell B test, as these indenters are typically associated with other Rockwell scales or hardness testing methods designed for harder materials. The specific design and size of the ball indenter cater to the requirements of the Rockwell B hardness test, making it ideal for the intended application.