Rockwell scale
Rockwell hardness scale based on indentation hardness of a material with a 120° diamond spheroconical under 150 kgf
en-GB/ɹɒkwɛl ˈskeɪl/
en-US/ˈɹɑˌkwɛl ˈskeɪl/
Rockwell hardness scale based on indentation hardness of a material with a 120° diamond spheroconical under 150 kgf