What are the hardness requirements according to NACE MR0175? Is 22HRC enough to meet NACE MR0175? What method should be used to measure hardness?

• 22HRC is not the only NACE MR0175 requirement (see this link).
• 22HRC applies for some carbon and low alloy steels, but 22HRC is not the hardness limit for all materials.
• The conversion of hardness readings to and from other scales is material dependent; there are hardness conversion tables such as ASTM E140, ISO 18265 . As per NACE MR0175, the user may establish the required conversion tables.