NIST Microform Calibration System for Rockwell Hardness Standardization

Published

August 25, 2008

Author(s)

Jun-Feng Song, Samuel R. Low III, Xiaoyu A. Zheng

Abstract

In the uncertainty budget of Rockwell hardness tests, microform geometric errors of the diamond indenter are a major contributor. The microform calibration of Rockwell diamond indenters has been one of the key steps for Rockwell hardness standardization. The National Institute of Standards and Technology (NIST) Microform Calibration System was developed for the microform calibration of standard Rockwell diamond indenters. Based on that system, the NIST Primary Standard Rockwell Indenter was established in 1995, by which nominally 300 standard reference material (SRM) 2810-2812 Rockwell C hardness (HRC) blocks were calibrated for implementation of the US National HRC Scale. During more than ten years of use for thousands hardness indentations, the NIST Primary Indenter was re-calibrated in 1997, 2005 and 2007. The calibration results have shown high stability for the NIST Primary Standard Rockwell Indenter and high measurement reproducibility for the NIST Microform Calibration System. The measurement setup, calibration and check standards, calibration procedure and uncertainty, calibration results and reproducibility for the NIST Microform Calibration System are described.

Proceedings Title

Proceedings of 4th International Symposium on Precision Mechanical Measurements (ISPMM 2008)

Conference Dates

August 18-22, 2008

Conference Location

Hefei

Conference Title

4th International Symposium on Precision Mechanical Measurements (ISPMM 2008)

Pub Type

Conferences

Keywords

Rockwell hardness, diamond indenter, microform calibration

Citation

Song, J. , Low, S. and Zheng, X. (2008), NIST Microform Calibration System for Rockwell Hardness Standardization, Proceedings of 4th International Symposium on Precision Mechanical Measurements (ISPMM 2008), Hefei, -1 (Accessed October 27, 2025)