<Li> ISO 2039 - 2: Plastics--Determination of hardness--Part 2: Rockwell hardness </Li> <Li> US standard (ASTM International) <Ul> <Li> ASTM E18: Standard methods for Rockwell hardness and Rockwell superficial hardness of metallic materials </Li> </Ul> </Li> <Ul> <Li> ASTM E18: Standard methods for Rockwell hardness and Rockwell superficial hardness of metallic materials </Li> </Ul> <Li> ASTM E18: Standard methods for Rockwell hardness and Rockwell superficial hardness of metallic materials </Li>

What is the rockwell hardness of a metal file