Which Rockwell scale is typically used for hard metals such as steel?

Which Rockwell scale is typically used for hard metals such as steel?

• A. B
• B. C
• C. A
• D. D

Answer: (B)

Rockwell hardness testing uses different scales that pair an indenter and a test load to cover different hardness ranges. For hard metals like steel, the scale with a diamond cone indenter and a higher test load is used, giving reliable readings in the higher end of the hardness spectrum (the HRC range). The ball-indenter scale with a lighter load is designed for softer metals and alloys and doesn’t measure very hard steels as effectively. So, when assessing hard metals such as steel, the appropriate choice is the scale that uses the diamond indenter with the higher load.

Rockwell hardness testing uses different scales that pair an indenter and a test load to cover different hardness ranges. For hard metals like steel, the scale with a diamond cone indenter and a higher test load is used, giving reliable readings in the higher end of the hardness spectrum (the HRC range). The ball-indenter scale with a lighter load is designed for softer metals and alloys and doesn’t measure very hard steels as effectively. So, when assessing hard metals such as steel, the appropriate choice is the scale that uses the diamond indenter with the higher load.