Based on a stylus technique, a microform calibration system was developed at NIST for the direct verification of Rockwell diamond indenters. The least-squares radius and profile deviations, cone angle and cone flank straightness, and the holder axis alignment error can be calibrated with traceability to fundamental measurements. The expanded measurement uncertainties are less than 1/10 of tolerance requirements of calibration-grade Rockwell diamond indenters specified in ASTM and ISO standards. The calibration requirements, instrument setup, calibration and check standards, calibration and uncertainty procedure, and the calibration results are described. Based on this calibration system, the use of the NIST standard-grade Rockwell diamond indenters is also suggested for the establishment of the reference-value scale for a metrology-based Rockwell hardness standard system and for the unification of Rockwell hardness standards.
Proceedings Title: Proceedings of the 9th International Symposium of Hardness Testing in Theory and Practice
Conference Dates: November 23-24, 1995
Conference Location: Dusseldorf, GE
Pub Type: Conferences