The Brinell scale/brəˈnɛl/ 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.
Proposed by SwedishengineerJohan 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. However, it also had the useful feature that the hardness value divided by two gave the approximate UTS in ksi for steels. This feature contributed to its early adoption over competing hardness tests.
Test detailsedit
The typical test uses a 10 mm (0.39 in) diametersteel 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:
where:
BHN = Brinell Hardness Number (kgf/mm2)
P = applied load in kilogram-force (kgf)
D = diameter of indenter (mm)
d = diameter of indentation (mm)
Brinell hardness is sometimes quoted in megapascals; the Brinell hardness number is multiplied by the acceleration due to gravity, 9.80665 m/s2, to convert it to megapascals.
The BHN can be converted into the ultimate tensile strength (UTS), although the relationship is dependent on the material, and therefore determined empirically. The relationship is based on Meyer's index (n) from Meyer's law. If Meyer's index is less than 2.2 then the ratio of UTS to BHN is 0.36. If Meyer's index is greater than 2.2, then the ratio increases.[1]
BHN 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.
HBW is calculated in both standards using the SI units as
where:
F = applied load (newtons)
D = diameter of indenter (mm)
d = diameter of indentation (mm)
Common valuesedit
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 carbide (from the chemical symbol for tungsten or from the Spanish/Swedish/German name for tungsten, "Wolfram") 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.
The hardness may also be shown as XXX HB YYD2. The XXX is the force to apply (in kgf) on a material of type YY (5 for aluminum alloys, 10 for copper alloys, 30 for steels). Thus a typical steel hardness could be written: 250 HB 30D2. It could be a maximum or a minimum.
Correspondent relations among scale, indenter and test force:
Brinell Hardness HB conversion chart (MPa, Brinell, Vickers, Rockwell C)
February 15, 2024
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BHN redirects here For other uses see BHN disambiguation The Brinell scale b r e ˈ n ɛ l 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 Force diagram Contents 1 History 2 Test details 3 Common values 4 Standards 5 See also 6 References 7 External linksHistory editProposed by 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 However it also had the useful feature that the hardness value divided by two gave the approximate UTS in ksi for steels This feature contributed to its early adoption over competing hardness tests Test details editThe 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 BHN 2 P p D D D 2 d 2 displaystyle operatorname BHN frac 2P pi D left D sqrt D 2 d 2 right nbsp where BHN Brinell Hardness Number kgf mm2 P applied load in kilogram force kgf D diameter of indenter mm d diameter of indentation mm Brinell hardness is sometimes quoted in megapascals the Brinell hardness number is multiplied by the acceleration due to gravity 9 80665 m s2 to convert it to megapascals The BHN can be converted into the ultimate tensile strength UTS although the relationship is dependent on the material and therefore determined empirically The relationship is based on Meyer s index n from Meyer s law If Meyer s index is less than 2 2 then the ratio of UTS to BHN is 0 36 If Meyer s index is greater than 2 2 then the ratio increases 1 BHN 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 HBW is calculated in both standards using the SI units as HBW 0 102 2 F p D D D 2 d 2 displaystyle operatorname HBW 0 102 frac 2F pi D left D sqrt D 2 d 2 right nbsp where F applied load newtons D diameter of indenter mm d diameter of indentation mm Common values editWhen 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 carbide from the chemical symbol for tungsten or from the Spanish Swedish German name for tungsten Wolfram 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 The hardness may also be shown as XXX HB YYD2 The XXX is the force to apply in kgf on a material of type YY 5 for aluminum alloys 10 for copper alloys 30 for steels Thus a typical steel hardness could be written 250 HB 30D2 It could be a maximum or a minimum Correspondent relations among scale indenter and test force Hardness symbol Diameter of Indenter mm F D2 Test force N kgfHBW 10 3000 10 30 29420 3000 HBW 10 1500 10 15 14710 1500 HBW 10 1000 10 10 9807 1000 Brinell hardness numbers Material HardnessSoftwood e g pine 1 6 HBS 10 100Hardwood 2 6 7 0 HBS 10 100Lead 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 HBCopper 35 HBHardened AW 6060 Aluminium 75 HBMild steel 120 HB18 8 304 stainless steel annealed 200 HB 3 Quenched and tempered steel wear plate 400 700 HBHardened tool steel 600 900 HB HBW 10 3000 Glass 1550 HBRhenium diboride 4600 HBNote Standard test conditions unless otherwise statedStandards editInternational ISO and European CEN Standard EN ISO 6506 1 2014 Metallic materials Brinell hardness test Part 1 test method EN ISO 6506 2 2017 Metallic materials Brinell hardness test Part 2 verification and calibration of testing machine EN ISO 6506 3 2014 Metallic materials Brinell hardness test Part 3 calibration of reference blocks EN ISO 6506 4 2014 Metallic materials Brinell hardness test Part 4 Table of hardness values US standard ASTM International ASTM E10 14 Standard method for Brinell hardness of metallic materials See also editBrinelling Hardness comparison Knoop hardness test Leeb rebound hardness test Rockwell scale Vickers hardness testReferences edit Tabor 2000 p 17 ASTM E10 14 AISI Type 304 Stainless Steel ASM Material Data Sheet n d Archived from the original on 1 October 2018 Retrieved 28 May 2019 Tabor David 2000 The Hardness of Metals Oxford University Press ISBN 0 19 850776 3 External links editBrinell Hardness Test Methods advantages disadvantages applications Video on the Brinell hardness test on YouTube Rockwell to Brinell conversion chart Brinell Rockwell A B C Struers hardness conversion table Vickers Brinell Rockwell B C D Brinell Hardness HB conversion chart MPa Brinell Vickers Rockwell C Retrieved from https en wikipedia org w index php title Brinell scale amp oldid 1184942059, wikipedia, wiki, book, books, library,
