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number symbol name Mohs hardness [1] Vickers hardness ... iron: 4.0: 608: 200-1180: 27: Co: cobalt: 5.0: ... Mohs hardness of materials (data page) ...
The Rockwell hardness test is a hardness test based on indentation hardness of a material. The Rockwell test measures the depth of penetration of an indenter under a large load (major load) compared to the penetration made by a preload (minor load). [ 1 ]
Vickers hardness numbers are reported as xxxHVyy, e.g. 440HV30, or xxxHVyy/zz if duration of force differs from 10 s to 15 s, e.g. 440HV30/20, where: 440 is the hardness number, HV names the hardness scale (Vickers), 30 indicates the load used in kgf. 20 indicates the loading time if it differs from 10 s to 15 s
A variety of hardness-testing methods are available, including the Vickers, Brinell, Rockwell, Meyer and Leeb tests. Although it is impossible in many cases to give an exact conversion, it is possible to give an approximate material-specific comparison table for steels .
Hardness may be difficult to determine, or may be misleading or meaningless, if a material is a mixture of two or more substances; for example, some sources have assigned a Mohs hardness of 6 or 7 to granite but it is a rock made of several minerals, each with its own Mohs hardness (e.g. topaz-rich granite contains: topaz — Mohs 8, quartz ...
An increase in the carbon content will cause a significant increase in the hardness and tensile strength of iron. Maximum hardness of 65 R c is achieved with a 0.6% carbon content, although the alloy has low tensile strength. [132] Because of the softness of iron, it is much easier to work with than its heavier congeners ruthenium and osmium. [17]
Brinell hardness numbers Material Hardness Softwood (e.g., pine) 1.6 HBS 10/100 Hardwood: 2.6–7.0 HBS 10/100 Lead: 5.0 HB (pure lead; alloyed lead typically can range from 5.0 HB to values in excess of 22.0 HB) Pure Aluminium: 15 HB Copper: 35 HB Hardened AW-6060 Aluminium: 75 HB Mild steel: 120 HB 18–8 (304) stainless steel annealed: 200 ...
"Hardness" in the elastic range—a small temporary change in shape for a given force—is known as stiffness in the case of a given object, or a high elastic modulus in the case of a material. They exhibit plasticity —the ability to permanently change shape in response to the force, but remain in one piece.