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Hardness Standard Reference Materials (SRM)


The Materials Science and Engineering Division produces SRMs as part of its efforts on the standardization of hardness measurement. SRMs currently in inventory cover the Rockwell C Scale as well as the Knoop and Vickers Microhardness Scales.

Standard Products

NIST Rockwell SRMs are transfer standards intended for use in the calibration and verification of the performance of hardness equipment using the Rockwell C and N Hardness Scales (HRC and HRN).

NIST Microindentation Hardness SRMs are for use in calibrating and checking the performance of microhardness testers using the Knoop and Vickers Hardness scales (HK and HV).


Hardness measurement is one of the most common criteria used in acceptance methods in the steel industry. In addition, microhardness methods are used as control variables in quality assurance in the microelectronics industry. Customers of these SRMs include the industries that presently require traceability to a National Metrology Institution, secondary standard producers, instrument manufacturers, and end users as well.

Current Efforts

In addition to maintaining the present inventory, current efforts are underway for the development of Brinell Scale SRMs.

Rockwell SRMs offered

For availability and purchase information, please click here.

Microhardness SRMs offered

For availability and purchase information, please click here.


Created November 23, 2008, Updated February 14, 2020