Brinell scale 458675 225773631 2008-07-15T09:53:33Z TXiKiBoT 3171782 robot Adding: [[bg:Метод на Бринел]] [[Image:BrinellSkizze.jpg|thumb|200px|Force diagram]] The '''Brinell scale''' characterizes the indentation [[hardness]] of materials through the scale of penetration of an indenter, loaded on a material test-piece. It is one of several definitions of [[hardness]] in [[materials science]]. '''Brinelling''' refers to surface fatigue caused by repeated impact or overloading. It is a common cause of [[Bearing (mechanical)|roller bearing]] failures, and loss of [[preload (engineering)|preload]] in [[bolted joint]]s when a hardened washer is not used. Engineers will use the Brinell hardness of materials in their calculations to avoid this mode of failure. Fretting corrosion can cause a similar-looking kind of damage and is called [[false brinelling]] since the mechanism is different. Proposed by [[Sweden|Swedish]] [[engineer]] [[Johan August Brinell]] in 1900, it was the first widely used and standardised hardness test in [[engineering]] and [[metallurgy]]. The large size of indentation and possible damage to test-piece limits its usefulness. The typical test uses a 10 [[millimeter|mm]] [[diameter]] [[steel]] ball as an indenter with a 3,000 [[Kilogram-force|kgf]] (29 kN) 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: :<math>\mbox{BHN}=\frac{2P}{\pi D ({D-\sqrt{(D^2-d^2)})}}</math> where: :''P'' = applied force ([[kgf]]) :''D'' = diameter of indenter (mm) :''d'' = diameter of indentation (mm) == Common values == When quoting a Brinell Hardness Number (BHN or more commonly HB), the conditions of the test used to obtain the number must be specified. The standard format for specifying tests can be seen in the example "HBW 10/3000". "HBW" means that a [[tungsten]] (chemical symbol W, from the German Wolfram) carbide ball indenter was used, as opposed to "HBS", which means a hardened steel ball. The "10" is the ball diameter in millimeters. The "3000" is the force in kilograms force. {| class="wikitable" |+ Brinell Hardness Numbers (standard test conditions unless otherwise stated) !Material!!Hardness |- |[[Softwood]] (e.g., [[pine]])||1.6 HBS 10/100 |- |[[Hardwood]]||2.6 to 7.0 HBS 1.6 10/100 |- |[[Aluminium]]||15 HB |- |[[Copper]]||35 HB |- |[[Mild steel]]||120 HB |- |18-8 (304) [[stainless steel]]||1250 HB |- |[[Glass]]||1550 HB |- |[[tool steel|Hardened tool steel]]||1500 - 1900 HB |- |[[Rhenium diboride|Rhenium Diboride]]||4600 HB |} ==[[International standard|Standards]]== * International ([[International Organization for Standardization|ISO]]) and European ([[CEN]]) Standard :* EN ISO 6506-1 : Metallic materials - Brinell hardness test - Part 1 : test method. :* EN ISO 6506-2 : Metallic materials - Brinell hardness test - Part 2 : verification and calibration of testing machine. :* EN ISO 6506-3 : Metallic materials - Brinell hardness test - Part 3 : calibration of reference blocks * US standard ([[ASTM International]]) :*[[ASTM]] E10 : : Standard method for Brinell hardness of metallic materials. ==See also== * [[Vickers hardness test]] * [[Rockwell scale]] * [[Knoop hardness test]] * [[Hardness comparison]] == External links == *[http://www.engineersedge.com/hardness_conversion.htm Rockwell to Brinell conversion chart] * [http://www.struers.com/default.asp?top_id=5&main_id=25&doc_id=344&target=_self&collapse=1 Struers hardness conversion table] [[Category:Hardness tests]] [[Category:Dimensionless numbers]] [[bg:Метод на Бринел]] [[cs:Zkouška tvrdosti podle Brinella]] [[de:Härte#Härteprüfung nach Brinell]] [[et:Brinelli kõvadus]] [[es:Dureza Brinell]] [[fr:Échelle de Brinell]] [[ko:브리넬 굳기]] [[it:Scala di Brinell]] [[he:שיטת ברינל]] [[hu:Brinell-keménység]] [[nl:Brinellhardheid]] [[pl:Skala twardości Brinella]] [[pt:Dureza Brinell]] [[ru:Метод Бринелля]] [[sl:Trdota po Brinellu]] [[sv:Brinellprovning]] [[th:การวัดความแข็งบริเนล]] [[uk:Метод Брінелля]] [[zh:布氏硬度试验]]