Ever wonder how the various hardness tests are conducted?
The Rockwell Hardness, Vickers Hardness, Brinell Hardness, and Charpy Impact tests are shown on YouTube. A search of the ANSI standards webstore shows standards for each test and standards for materials, tools and supplies using the measures as a specification. Search hardness standards by keyword on the ANSI webstore. These standards find applicability in testing metals, plastics and ceramics. The various hardness tests involve application of pressure with different shaped probes.
ASTM E140-12B(2019)e1 provides tables to convert from one scale to another:
Standard Hardness Conversion Tables for Metals Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Superficial Hardness, Knoop Hardness, Scleroscope Hardness, and Leeb Hardness.
Other standards provide guidance on calibration of reference blocks.