what is the engineering term for hardness of a material?
103397
The hardness of general materials such as minerals is often compared to a list of materials on Mohs hardness scale which runs from talc (softest) to diamond (hardest).\n\nMany metals are checked for hardness by measuring the resistance to a small spherical or diamond shaped stylus as it is pushed (impressed) into the metal.  There are numerous scales available depending on overall hardness of the metal in question (and the testing machines readily available).
367986
The two hardnesses you are looking for must be scratch and indentation hardness.\n\nScratch hardness is caracterized by the Mohs scale (as commented before).\n\nIndentation hardness is caracterized by serveral scales, the most popular (here, in colombia) are the Rockwell hardness test and the Shore durometer.\n\nThe wikipedia link has in itself references to detailded information about many hardness scales that you may find useful
196140
Hardness Mineral Absolute Hardness \n1 Talc \n(Mg3Si4O10(OH)2)\n 1 \n2 Gypsum (CaSO4·2H2O) 2 \n3 Calcite (CaCO3) 9 \n4 Fluorite (CaF2) 21 \n5 Apatite \n(Ca5(PO4)3(OH-,Cl-,F-))\n 48 \n6 Orthoclase Feldspar (KAlSi3O8) 72 \n7 Quartz (SiO2) 100 \n8 Topaz (Al2SiO4(OH-,F-)2) 200 \n9 Corundum (Al2O3) 400 \n10 Diamond (C) 1500 \nIt goes from the level of hardness to a mineral and absolute hardness.
763583
If it was me, I would specify the Ra or RMS value, the surface type (cast, machined, polished, ect...), and also the surface hardness (Rockwell B or C scale).  If you have access to a Machinery's Handbook, check it out.
115545
The strict materials definition of glass is a uniform amorphous solid material produced when a suitably viscous molten material cools very rapidly not giving enough time for a regular crystal lattice to form.\nNormal glass like in a window is made from mostly silicon dioxide.\nMany different manufacturing processes, the most used is the float or annealing process.
832756
The hardest form of carbon is diamond, but graphite could also be considered hard carbon.
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Well, a clear question would help. \n\nAre you trying to calculate the power that a certain material can withstand?   Or are you trying to calculate strength?
12738
The IUPAC Compendium defines work softening as: (I quote)\n\n"work softening\nThe application of a finite shear to a system after a long rest may result in\na decrease of the viscosity or the consistency. If the decrease persists when\nthe shear is discontinued, this behaviour is called work softening (or shear\nbreakdown), whereas if the original viscosity or consistency is recovered\nthis behaviour is called thixotropy."\n\nAs I understand it, under extremely high strain levels some materials (e.g. Al alloys) will exhibit a gradual decrease in the hardness. Lower strain rates will produce work hardening, increasing the hardness of the material.
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Diamond is the hardest known naturally occurring material, scoring 10 on the relative Mohs scale of mineral hardness and having an absolute hardness value of between 167 and 231 gigapascals in various tests. Diamond's hardness has been known since antiquity, and is the source of its name. However, aggregated diamond nanorods, an allotrope of carbon first synthesized in 2005, are now believed to be even harder than diamond.
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It all depends on the metal.\n\nSome metals are soft in nature, but when alloyed with others can become very hard and strong.  Combining iron and carbon with Molybdenum and Nickel can make a very hard, but brittle steel.  \n\nCopper by itself is very soft and easy to work.  Combine it with tin and you get Bronze (a harder metal) or with antimony to get brass (harder still).\n\nHeat treatments also affect the hardness.  When a metal is heated, the crystals essentially "reset" themselves to be in an amorphous state.  A rapid cooling such as a water or oil quench will cause small, tightly packed grains, creating a hard metal.  A slow cooling will result in a softer material that is easier to work with.
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Ruby, a form of Corundum has a hardness of 9 on the Moh's Scale.\n\nCalcite is a 3 \nK-Spar is a 6\nAgate is a 7
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Since no-one else has answered the question yet, I'll take a stab at it -\n\nI think the term you're looking for is Hysteresis
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Hardness- materials such as a fingernail, penny, and ceramic tile can be used to determine the hardness of a mineral on the Mohs scale.
396032
Firstly, pencil lead IS graphite.  O.k, back to your question.  Both graphite and diamond are allotropic forms of carbon- they differ in the spatial arrangement of their molecules a lattice.  In diamond, the carbon atoms are arranged in a regular tetrahedral spatial arrangement, while in graphite, the carbons are arranged in an irregular "stacked" manner.  This structural difference results in different properties of hardness.  Diamond is the hardest substance known, with a Moh's scale reading of 10, while graphite is very soft and has a rating of approximately 1.
85947
These metals are softer than others (ex. steel) and will self-anneal at room temperature, thus counteracting the strain hardening.
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http://www.indiaxpress.com/au/coe/dept/met/Metallurgical_Engg_Catalog.pdf\n\nhttp://engineering-services.globalspec.com/Industrial-Directory/tester_model\n\nor google "poldi hardness testing principle"
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Annealed....can't think of one, this is softened steel which is highly malleable. This condition is often used to shape steel in its soft condition and then tempered after during a process.\n\nTempered, the perfect example is a medieval sword, which needed to retain a sharp edge, while being flexible to avoid breaking during combat. A modern consumer product could be a hunting knife, a bowie knife etc.\n\nHardened means that the steel is extremely hard and wear resistant, but very brittle and is easily broken or shattered. A modern consumer product would be a steel file. (for shaping softer steel)