What balls are used for erichsen cupping test?

The Erichsen cupping test typically uses a steel ball as the indenter. The ball is usually 10mm in diameter, but other sizes can be used depending on the specific test requirements.

Here's why a steel ball is used:

* Consistent shape: The spherical shape of the ball ensures consistent contact with the test specimen, leading to reproducible results.

* Hardness: Steel balls are hard enough to penetrate the material being tested, but not so hard that they damage the specimen.

* Smoothness: The smooth surface of the ball minimizes friction and ensures accurate measurements.

While a steel ball is the standard, other materials like carbide or ceramic balls may be used in specific applications depending on the material being tested and the desired test parameters.