NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
NIST Recommended Practice Guide: Rockwell Hardness Measurement of Metallic Materials
Published
Author(s)
Samuel R. Low III
Abstract
The Rockwell hardness test continues to be applied as a tool for assessing the properites of a product while the tolerances on the acceptable material hardness have become tighter and tighter. Adhering to good practice procedures when performing Rockwell hardness measurements and calibrations is a beneficial step to reducing measurement errors. The purpose of this Guide is to explain the causes of variability in Rockwell hardness test results and to supplenment the information given in test method standards with good practice recommendations. Although this Guide is directed more towards the users of Rockwell hardness having the greatest concern for accuracy in their measurements, much of the information given is also applicable to users that only require test results to be within wide tolerance bands, where high accuracy is not as critical.
error, hardness, indentation, indenter, rockwell, standardization, test block, test method, verification
Citation
Low, S.
(2001),
NIST Recommended Practice Guide: Rockwell Hardness Measurement of Metallic Materials, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=853006
(Accessed October 9, 2025)