Purpose

The Metallurgy 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 Hardness Scale (HRC). Each SRM unit is a steel test block, nominally 64 mm in diameter and 15 mm thick, with a polished test surface described by a engraved circle 52 mm in diameter. Seven indents spread throughout the test surface are used for the certification of hardness values.

NIST Microindentation Hardness SRMs are for use in calibrating and checking the performance of microhardness testers and may be used in conjunction with ASTM E 384. These SRMs were made by electroforming the test metal (bright copper or bright nickel) on AISI 1010 steel substrates. Each SRM is indented five times for each load used during certification and is individually certified for average hardness value.

Customers

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 Rockwell N Scale SRMs as well as higher hardness steel Microhardness SRMs (800 HK and 800 HV scales).

Rockwell SRMs offered

For availability and purchase information, please click here.

Microhardness SRMs offered

For availability and purchase information, please click here.