In Rockwell C hardness testing, what indenter and load are used?

In Rockwell C hardness testing, what indenter and load are used?

• A. Cone indenter with 150 kg load
• B. 2 mm ball with 100 kg load
• C. Diamond indenter with 60 kg load
• D. Cone indenter with 100 kg load

Answer: (A)

In Rockwell C hardness testing, a precise indenter geometry and a standardized major load are used to create a consistent indentation depth that correlates to hardness. The C scale uses a diamond cone indenter (a defined 120-degree diamond cone) and a major load of 150 kgf, typically with a small preliminary minor load to form the indentation before applying the major load. This setup is chosen because it produces a measurable, repeatable indentation in hard steels, enabling reliable comparisons between specimens. Indenters like a ball are used for other scales or tests, and using a different major load with the same cone indenter would not meet the standard for Rockwell C.

In Rockwell C hardness testing, a precise indenter geometry and a standardized major load are used to create a consistent indentation depth that correlates to hardness. The C scale uses a diamond cone indenter (a defined 120-degree diamond cone) and a major load of 150 kgf, typically with a small preliminary minor load to form the indentation before applying the major load. This setup is chosen because it produces a measurable, repeatable indentation in hard steels, enabling reliable comparisons between specimens. Indenters like a ball are used for other scales or tests, and using a different major load with the same cone indenter would not meet the standard for Rockwell C.