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ISO 18265: "Metallic materials — Conversion of hardness values" (2013) ASTM E140-12B(2019)e1: "Standard Hardness Conversion Tables for Metals Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Superficial Hardness, Knoop Hardness, Scleroscope Hardness, and Leeb Hardness" (2019)
The superficial Rockwell scales use lower loads and shallower impressions on brittle and very thin materials. The 45N scale employs a 45-kgf load on a diamond cone-shaped Brale indenter, and can be used on dense ceramics. The 15T scale employs a 15-kgf load on a 1 ⁄ 16-inch-diameter (1.588 mm) hardened steel ball, and can be used on sheet metal.
The Brinell hardness is designated by the most commonly used test standards (ASTM E10-14 [2] and ISO 6506–1:2005) as HBW (H from hardness, B from brinell and W from the material of the indenter, tungsten (wolfram) carbide). In former standards HB or HBS were used to refer to measurements made with steel indenters.
Several such tests exist, wherein the examined material is indented until an impression is formed; these tests can be performed on a macroscopic or microscopic scale. When testing metals, indentation hardness correlates roughly linearly with tensile strength , [ 1 ] but it is an imperfect correlation often limited to small ranges of strength ...
The Vickers test can be used for all metals and has one of the widest scales among hardness tests. The unit of hardness given by the test is known as the Vickers Pyramid Number (HV) or Diamond Pyramid Hardness (DPH). The hardness number can be converted into units of pascals, but should not be confused with pressure, which uses the same units ...
The geometry of this indenter is an extended pyramid with the length to width ratio being 7:1 and respective face angles are 172 degrees for the long edge and 130 degrees for the short edge. The depth of the indentation can be approximated as 1/30 of the long dimension. [1] The Knoop hardness HK or KHN is then given by the formula:
1.0 in⋅ozf (7.1 mJ) inoz-f in⋅oz f: horsepower-hour: hph hp⋅h 1.0 hp⋅h (0.75 kWh) British thermal unit: British thermal unit: Btu Btu The International Steam Table British thermal unit is used. For others, see the full list. 1.0 Btu (1.1 kJ) BTU BTU TNT-based units: gigatonne of TNT: GtTNT (none) 1.0 gigatonne of TNT (4.2 EJ) gigaton of ...
The Leeb quotient (v i,v r) is taken as a measure of the energy loss by plastic deformation: the impact body rebounds faster from harder test samples than it does from softer ones, resulting in a greater value 1000×v r /v i. A magnetic impact body permits the velocity to be deduced from the voltage induced by the body as it moves through the ...