Recent Developments in Hardness Testing and their Implications for Standardisation

Abstract

This paper discusses two current developments in the field of hardness testing. Recent proposals for the Rockwell C scale should make it possible for a ‘Unified’ Rockwell scale with agreement between National Standards Laboratories within 0.1 HRC. The need for better understanding of the Ultra Micro Indentation Test, where force and penetration are recorded simultaneously, will also be discussed. Difficulties in standardisation of this technique are exacerbated by metrological problems, a diversity of terminology and numerous variations to the method.