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number symbol name Mohs hardness [1] Vickers hardness (MPa) [1] Brinell hardness (MPa) [1] Brinell hardness (MPa) [note 1] [2] 3: Li: lithium: 0.6: 5: 4: Be: beryllium: 5.5: 1670: 590–1320: 5: B: boron
Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale The Mohs scale ( / m oʊ z / MOHZ ) of mineral hardness is a qualitative ordinal scale , from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material.
[3] [4] The Mohs scale is based on relative scratch hardness of different materials; with talc assigned a value of 1 and diamond assigned a value of 10. [5] Mohs's scale had two limitations: it was not linear, and most modern abrasives fall between 9 and 10.; [6] [7] so, later scientists attempted to increase resolution at the harder end of the ...
MIL-DTL-46100E specifies a steel of identical hardness. [3] MIL-DTL-32332 specifies ultra-hard steel, with Brinell hardness in excess of 570. [3] A Chinese publication lists 30MnCrNiMo "685" steel as the material used in Chinese rolled armor plates, with a Brinell Hardness of HBW 444-514 (thin) / 429-495 (thick).
Silicon carbide (SiC), also known as carborundum (/ ˌ k ɑːr b ə ˈ r ʌ n d əm /), is a hard chemical compound containing silicon and carbon. A wide bandgap semiconductor , it occurs in nature as the extremely rare mineral moissanite , but has been mass-produced as a powder and crystal since 1893 for use as an abrasive .
Under the table, the text says that a steel file has a hardness of 6.5 and a streak plate has a hardness of 7. Neither of the two footnoted links in that section give a hardness for a "steel file". One gives a "steel nail" as 5.5, and the other gives a "steel needle" as 6.5. They give different hardnesses for a streak plate, 6.5 vs. 7.
The typical test uses a 10 mm (0.39 in) diameter steel ball as an indenter with a 3,000 kgf (29.42 kN; 6,614 lbf) force. For softer materials, a smaller force is used; for harder materials, a tungsten carbide ball is substituted for the steel ball. The indentation is measured and hardness calculated as:
Stainless steel is a popular class of material for knife blades because it resists corrosion and is easy to maintain. However, it is not impervious to corrosion or rust. For a steel to be considered stainless it must have a Chromium content of at least 10.5%. [24] 154CM / ATS-34 steels. These two steels are practically identical in composition ...