Rockwell scale Rockwell scale The Rockwell scale is a hardness scale based on indentation hardness of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload. There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, HRB, HRC, etc., where the last letter is the respective Rockwell scale (see below). When testing metals, indentation hardness correlates linearly with tensile strength. This important relation permits economically important nondestructive testing of
71 Harrington Street, The Rocks Iron. As at 27 April 2001, Archaeology Assessment Condition: Partly disturbed. Assessment Basis: Area under building only. Terraced into hill slope. As at 30 March 2011, this house and site are of State heritage significance for their historical and scientific cultural values. The site and building are also of State heritage significance for their contribution to The Rocks area which is of State Heritage significance in its own right. The site has historical significance as part of the Colony's hospital site in 1807, and the building as part of the 19th century housing stock in The Rocks. It has aesthetic