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The Vickers hardness test was developed in 1921 by Robert L. Smith and George E. Sandland at Vickers Ltd as an alternative to the Brinell method to measure the hardness of materials.^[1] The Vickers test is often easier to use than other hardness tests since the required calculations are independent of the size of the indenter, and the indenter can be used for all materials irrespective of hardness. The basic principle, as with all common measures of hardness, is to observe the questioned material's ability to resist plastic deformation from a standard source. The Vickers test can be used for all metals and has one of the widest scales among hardness tests. The unit of hardness given by the test is known as the Vickers Pyramid Number (HV) or Diamond Pyramid Hardness (DPH). The hardness number can be converted into units of pascals, but should not be confused with a pressure, which also has units of pascals. The hardness number is determined by the load over the surface area of the indentation and not the area normal to the force, and is therefore not a pressure.

Implementation

It was decided that the indenter shape should be capable of producing geometrically similar impressions, irrespective of size; the impression should have well-defined points of measurement; and the indenter should have high resistance to self-deformation. A diamond in the form of a square-based pyramid satisfied these conditions. It had been established that the ideal size of a Brinell impression was 3/8 of the ball diameter. As two tangents to the circle at the ends of a chord 3d/8 long intersect at 136°, it was decided to use this as the included angle of the indenter, giving an angle to the horizontal plane of 22° on each side. The angle was varied experimentally and it was found that the hardness value obtained on a homogeneous piece of material remained constant, irrespective of load.^[2] Accordingly, loads of various magnitudes are applied to a flat surface, depending on the hardness of the material to be measured. The HV number is then determined by the ratio F/A, where F is the force applied to the diamond in kilograms-force and A is the surface area of the resulting indentation in square millimeters. A can be determined by the formula.

A={\frac {d^{2}}{2\sin(136^{\circ }/2)}},

which can be approximated by evaluating the sine term to give

A\approx {\frac {d^{2}}{1.8544}},

where d is the average length of the diagonal left by the indenter in millimeters. Hence,^[3]

HV={\frac {F}{A}}\approx {\frac {1.8544F}{d^{2}}}

,

where F is in kgf and d is in millimeters.

The corresponding units of HV are then kilograms-force per square millimeter (kgf/mm²). To calculate Vickers hardness number using SI units one needs to convert the force applied from kilogram-force to newtons by multiplying by 9.806 65 (standard gravity) and dividing by a factor of 1000 to get the answer in GPa. To do the calculation directly, the following equation can be used:^[4]

HV={\frac {F}{A}}\approx {\frac {0.01819F}{d^{2}}},

where F is in N and d is in millimeters. Here, HV is in GPa and should be roughly between 0-15 GPa.

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 gives 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

Vickers values are generally independent of the test force: they will come out the same for 500 gf and 50 kgf, as long as the force is at least 200 gf.^[5]

For thin samples indentation depth can be an issue due to substrate effects. As a general rule of thumb the sample thickness should be kept greater than 2.5 times the indent diameter. Alternatively indent depth can be calculated according to:

h={\frac {d}{2{\sqrt {2}}\tan {\frac {\theta }{2}}}}\approx {\frac {d}{7.0006}},

Examples of HV values for various materials^[6]
Material	Value
316L stainless steel	140HV30
347L stainless steel	180HV30
Carbon steel	55–120HV5
Iron	30–80HV5
Martensite	1000HV
Diamond	10000HV

Precautions

When doing the hardness tests the minimum distance between indentations and the distance from the indentation to the edge of the specimen must be taken into account to avoid interaction between the work-hardened regions and effects of the edge. This minimum distances are different for ISO 6507-1 and ASTM E384 standards.

Standard	Distance between indentations	Distance from the center of the indentation to the edge of the specimen
ISO 6507-1	> 3·d for steel and copper alloys and > 6·d for light metals	2.5·d for steel and copper alloys and > 3·d for light metals
ASTM E384	2.5·d	2.5·d

Estimating tensile strength

If HV is expressed in ${\mbox{kg/mm}}^{2}$ the tensile strength (in MPa) of the material can be approximated as:

${\sigma _{u}}\approx {\mathbb {H} _{V}}*c\approx {\mathbb {H} _{V}}*{3.33}$

where c is a constant determined by geometrical factors usually ranging between 2 and 4. ^[7]

Application

The fin attachment pins and sleeves in the Convair 580 airliner were specified by the aircraft manufacturer to be hardened to a Vickers Hardness specification of 390HV5, the '5' meaning five kiloponds. However on the aircraft flying Partnair Flight 394 the pins were later found to have been replaced with sub-standard parts, leading to rapid wear and finally loss of the aircraft. On examination, accident investigators found that the sub-standard pins had a hardness value of only some 200-230HV5.^[8]

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References

Notes

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro. Note 7 is a link to a source that gives conversion formula as Vickers Hardness (HV) ~ 0.3 × yield stress (in MPa) which is wrong as it should be Vickers Hardness (HV) ~ 0.3 × ultimate stress (in MPa)

Bibliography

20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

My blog: http://www.primaboinca.com/view_profile.php?userid=5889534

External links

Video on the Vickers hardness test
Vickers hardness test
Conversion table - Vickers, Brinell, and Rockwell scales

de:Härte#Härteprüfung nach Vickers (HV)

↑ R.L. Smith & G.E. Sandland, "An Accurate Method of Determining the Hardness of Metals, with Particular Reference to Those of a High Degree of Hardness," Proceedings of the Institution of Mechanical Engineers, Vol. I, 1922, p 623–641.
↑ http://www.ukcalibrations.co.uk/vickers_htm.html
↑ ASTM E384-10e2
↑ ISO 6507-1:2005
↑ Vickers Test. Instron website.
↑ Smithells Metals Reference Book, 8th Edition, ch. 22
↑ Template:Cite web
↑ http://www.aibn.no/aviation/reports/1993-02-eng

[1] R.L. Smith & G.E. Sandland, "An Accurate Method of Determining the Hardness of Metals, with Particular Reference to Those of a High Degree of Hardness," Proceedings of the Institution of Mechanical Engineers, Vol. I, 1922, p 623–641.

[2] ttp://www.ukcalibrations.co.uk/vickers_htm.html

[3] ASTM E384-10e2

[4] ISO 6507-1:2005

[5] Vickers Test. Instron website.

[6] Smithells Metals Reference Book, 8th Edition, ch. 22

[7] Template:Cite web

[8] ttp://www.aibn.no/aviation/reports/1993-02-eng

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

@@ Line 1: / Line 1: @@
-{{Starbox begin
+[[File:Vickers-tester.png|thumb|A Vickers hardness tester]]
- | name = Beta Librae
-}}
+The '''Vickers hardness test''' was developed in 1921 by Robert L. Smith and George E. Sandland at [[Vickers Ltd]] as an alternative to the [[Brinell scale|Brinell]] method to measure the [[hardness]] of materials.<ref>R.L. Smith & G.E. Sandland, "An Accurate Method of Determining the Hardness of Metals, with Particular Reference to Those of a High Degree of Hardness," ''[[Proceedings of the Institution of Mechanical Engineers]]'', Vol. I, 1922, p 623–641.</ref> The Vickers test is often easier to use than other hardness tests since the required calculations are independent of the size of the indenter, and the indenter can be used for all materials irrespective of hardness. The basic principle, as with all common measures of hardness, is to observe the questioned material's ability to resist plastic deformation from a standard source. The Vickers test can be used for all [[metal]]s and has one of the widest scales among hardness tests. The unit of hardness given by the test is known as the '''Vickers Pyramid Number''' ('''HV''') or '''Diamond Pyramid Hardness''' ('''DPH'''). The hardness number can be converted into units of [[pascal (unit)|pascals]], but should not be confused with a pressure, which also has units of pascals. The hardness number is determined by the load over the surface area of the indentation and not the area normal to the force, and is therefore not a pressure.
-{{Starbox image
-| image =
+== Implementation ==
-     <div style="position: relative">[[File:Libra IAU.svg|250px|alt=Diagram showing star positions and boundaries of the Libra constellation and its surroundings]]
+[[File:Vickers-path-2.svg|thumb|Vickers test scheme]]
-     <div style="position: absolute; left: 49.2%; top: 33.2%;">[[File:Cercle rouge 100%.svg|12px]]</div>
+[[File:Vickers anvil diamons.jpg|thumb|The pyramidal [[diamond]] indenter of a Vickers hardness tester.]]
-     </div>
+[[File:Case hardened steel-vickers hardness test.png|thumb|An indentation left in case-hardened steel after a Vickers hardness test. The difference in length of both diagonals and the illumination gradient, are both classic indications of an out-of-level sample. This is not a good indentation.]]
-| caption = The position of β Librae (circled)
-}}
+It was decided that the indenter shape should be capable of producing geometrically similar impressions, irrespective of size; the impression should have well-defined points of measurement; and the indenter should have high resistance to self-deformation. A diamond in the form of a square-based pyramid satisfied these conditions.  It had been established that the ideal size of a [[Brinell hardness test|Brinell]] impression was 3/8 of the ball diameter. As two tangents to the circle at the ends of a chord 3''d''/8 long intersect at 136°, it was decided to use this as the included angle of the indenter, giving an angle to the horizontal plane of 22° on each side. The angle was varied experimentally and it was found that the hardness value obtained on a homogeneous piece of material remained constant, irrespective of load.<ref>http://www.ukcalibrations.co.uk/vickers_htm.html</ref> Accordingly, loads of various magnitudes are applied to a flat surface, depending on the hardness of the material to be measured. The HV number is then determined by the ratio ''F/A'', where ''F'' is the force applied to the diamond in kilograms-force and ''A'' is the surface area of the resulting indentation in square millimeters. ''A'' can be determined by the formula.
-{{Starbox observe
- | epoch    = J2000
+: <math>A = \frac{d^2}{2 \sin(136^\circ/2)},</math>
- | ra       = {{RA|15|17|00.41382}}<ref name=aaa474_2_653/>
- | dec      = {{DEC|−09|22|58.4919}}<ref name=aaa474_2_653/>
+which can be approximated by evaluating the sine term to give
- | appmag_v = 2.61<ref name=scfs/>
-  | constell = [[Libra (constellation)|Libra]]
+: <math>A \approx \frac{d^2}{1.8544},</math>
-}}
-{{Starbox character
+where ''d'' is the average length of the diagonal left by the indenter in millimeters. Hence,<ref>ASTM E384-10e2</ref>
- | class    = B8&nbsp;V<ref name=apj736_2_89/>
- | b-v      = −0.106<ref name=apjs15_459/>
- | u-b      = −0.359<ref name=apjs15_459/>
- | variable = Suspected
-}}
-{{Starbox astrometry
- | radial_v = −35.2<ref name=scfs/>
- | prop_mo_ra  = −98.10<ref name=aaa474_2_653/>
- | prop_mo_dec = −19.65<ref name=aaa474_2_653/>
- | parallax = 17.62
- | p_error  = 0.16
- | parallax_footnote = <ref name=aaa474_2_653/>
- | absmag_v =
-}}
-{{Starbox detail
- | mass     = 3.5{{+-|0.3|0.2}}<ref name=apj736_2_89/>
- | radius   = 4.9<ref name=lang2006/>
- | luminosity  = 130
- | temperature = 12,300<ref name=aaa501_1_297/>
- | metal_fe    = 0.33<ref name=apj736_2_89/>
- | rotational_velocity = 250<ref name=apj573_1_359/>
- | age_myr  = 80{{+-|50|40}}<ref name=apj736_2_89/>
-}}
-{{Starbox catalog
- | names = Zubeneschemali, Lanx Borealis, 27 Librae, [[Bonner Durchmusterung|BD]]-08 3935, [[FK5]] 564, [[Henry Draper catalogue|HD]] 135742, [[Hipparcos catalogue|HIP]] 74785, [[Harvard Revised catalogue|HR]] 5685, NSV 7009, [[Smithsonian Astrophysical Observatory Star Catalog|SAO]] 140430.<ref name=SIMBAD/>
-}}
-{{Starbox end}}
-'''Beta Librae''' (β Lib, β Librae) is the [[Bayer designation]] for a [[star]] in the [[zodiac]] [[constellation]] of [[Libra (constellation)|Libra]]. It has the traditional name '''Zubeneschamali''' ({{IPAc-en|icon|ˌ|z|uː|b|ən|ˌ|ɛ|ʃ|ə|ˈ|m|eɪ|l|i}}) and the [[Latin]] name '''Lanx Borealis''',<ref name=lahire1727/> meaning "the northern scale [of the Balance]". The name '''''Zubeneschamali''''' is derived from the [[Arabic language|Arabic]] الزبن الشمالية (''al-zuban al-šamāliyya'')  meaning "The Northern Claw".<ref name="Auk"/> The [[apparent visual magnitude]] of this star is 2.6,<ref name=scfs/> making it the brightest member of Libra. From [[parallax]] measurements, its distance can be estimated as {{Convert|185|ly|pc|abbr=off|lk=on}} from [[Earth]].<ref name=aaa474_2_653/>
+: <math>HV = \frac{F}{A} \approx \frac{1.8544 F}{d^2}</math>,
-== Description ==
+where ''F'' is in [[kilogram-force|kgf]] and ''d'' is in millimeters.
-Based upon the features of its [[spectrum]], Beta Librae has a [[stellar classification]] of B8&nbsp;V,<ref name=apj736_2_89/> making it a [[B-type main sequence star]]. It is about 130 times more luminous than the Sun and has a surface temperature of 12,300&nbsp;[[Kelvin|K]],<ref name=aaa501_1_297/> double that of the Sun. This high temperature produces light with a simple [[spectrum]], making it ideal for examining the interstellar gas and dust between us and the star. Like many stars of its kind, it is spinning rapidly, over 100 times faster than the Sun with a [[projected rotational velocity]] of {{nowrap|250 km s<sup>–1</sup>}}.<ref name=apj573_1_359/> The measured [[angular diameter]] of the primary star is 0.801&nbsp;[[milliarcsecond|mas]].<ref name=aaa501_1_297/> At the estimated distance of this system, this yields a physical size of about 4.9 times the [[Solar radius|radius of the Sun]].<ref name=lang2006/> This type of massive, hydrogen-fusing star often appears blue-white, but Beta Librae is often described as greenish, the only greenish star visible to the naked eye.<ref name="uiuc"/>
-The small periodic variations in the magnitude of the Beta Librae suggests the presence of a companion star which is not directly observable from earth.<ref name="glyphweb"/> However, it is presently categorized as a single star.<ref name=mnras389_2_869/>
+The corresponding units of HV are then kilograms-force per square millimeter (kgf/mm²). To calculate Vickers hardness number using SI units one needs to convert the force applied from [[kilogram-force]] to newtons by multiplying by 9.806 65 ([[standard gravity]]) and dividing by a factor of 1000 to get the answer in GPa. To do the calculation directly, the following equation can be used:<ref>ISO 6507-1:2005</ref>
-==History==
+: <math>HV = \frac{F}{A} \approx \frac{0.01819 F}{d^2},</math>
-According to [[Eratosthenes]] Beta Librae was observed to be brighter than [[Antares]]. [[Ptolemy]], three hundred and fifty years later, said it was as bright as Antares. The discrepancy may be due to Antares becoming brighter, but this is not known for certain. It could simply be caused by Beta Librae being a [[variable star]], showing a present day variability of 0.03 of a magnitude.<ref name="Auk"/>
-== See also ==
+where ''F'' is in N and ''d'' is in millimeters. Here, HV is in GPa and should be roughly between 0-15 GPa.
-* [[List of stars in Libra]]
-* [[Beta Librae in fiction]]
-==References==
+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:
-{{reflist|refs=
-<ref name=aaa474_2_653>{{cite journal | title=Validation of the new Hipparcos reduction | last=van Leeuwen | first=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | month=November | year=2007 | pages=653–664 | doi=10.1051/0004-6361:20078357 | bibcode=2007A&A...474..653V |arxiv = 0708.1752 }}</ref>
+* '''440''' is the hardness number,
+* '''HV''' gives 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
-<ref name=scfs>{{citation | display-authors=1 | title=Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions | last1=Wielen | first1=R. | last2=Schwan | first2=H. | last3=Dettbarn | first3=C. | last4=Lenhardt | first4=H. | last5=Jahreiß | first5=H. | last6=Jährling | first6=R. | publisher=Astronomisches Rechen-Institut Heidelberg | issue=35 | year=1999 | bibcode=1999VeARI..35....1W | postscript=. }}</ref>
+Vickers values are generally independent of the test force: they will come out the same for 500 gf and 50 kgf, as long as the force is at least 200 gf.<ref>[http://www.instron.us/wa/applications/test_types/hardness/vickers.aspx Vickers Test]. [[Instron]] website.</ref>
-<ref name=apj736_2_89>{{citation | display-authors=1 | last1=Janson | first1=Markus | last2=Bonavita | first2=Mariangela | last3=Klahr | first3=Hubert | last4=Lafrenière | first4=David | last5=Jayawardhana | first5=Ray | last6=Zinnecker | first6=Hans | title=High-contrast Imaging Search for Planets and Brown Dwarfs around the Most Massive Stars in the Solar Neighborhood | journal=The Astrophysical Journal | volume=736 | issue=2 | page=89 | month=August | year=2011 | doi=10.1088/0004-637X/736/2/89 | bibcode=2011ApJ...736...89J |arxiv = 1105.2577 }}</ref>
+For thin samples indentation depth can be an issue due to substrate effects. As a general rule of thumb the sample thickness should be kept greater than 2.5 times the indent diameter. Alternatively indent depth can be calculated according to:
-<ref name=apj573_1_359>{{citation | last1=Abt | first1=Helmut A. | last2=Levato | first2=Hugo | last3=Grosso | first3=Monica | title=Rotational Velocities of B Stars | journal=The Astrophysical Journal | volume=573 | issue=1 | pages=359–365 | month=July | year=2002 | doi=10.1086/340590 | bibcode=2002ApJ...573..359A }}</ref>
+: <math>h = \frac{d}{2\sqrt{2}\tan{\frac{\theta}{2}}} \approx \frac{d}{7.0006},</math>
-<ref name=apjs15_459>{{citation | last1=Gutierrez-Moreno | first1=Adelina | last2=Moreno | first2=Hugo | title=A photometric investigation of the Scorpio-Centaurus association |  journal=Astrophysical Journal Supplement | volume=15 | page=459 | year=1968 | month=June | bibcode=1968ApJS...15..459G | doi=10.1086/190168 }}</ref>
+{| class="wikitable" border="1"
+|+ Examples of HV values for various materials<ref>Smithells Metals Reference Book, 8th Edition, ch. 22</ref>
+|-
+! Material !! Value
+|-
+| 316L stainless steel || 140HV30
+|-
+| 347L [[stainless steel]] || 180HV30
+|-
+| [[Carbon steel]] || 55–120HV5
+|-
+| [[Iron]] || 30–80HV5
+|-
+| [[Martensite]] || 1000HV
+|-
+| [[Diamond]] || 10000HV
+|}
-<ref name=aaa501_1_297>{{citation | display-authors=1 | last1=Zorec | first1=J. | last2=Cidale | first2=L. | last3=Arias | first3=M. L. | last4=Frémat | first4=Y. | last5=Muratore | first4=M. F. | last5=Torres | first5=A. F. | last6=Martayan | first6=C. | title=Fundamental parameters of B supergiants from the BCD system. I. Calibration of the (λ_1, D) parameters into Teff | journal=Astronomy and Astrophysics | volume=501 | issue=1 | pages=297–320 | month=July | year=2009 | doi=10.1051/0004-6361/200811147 | bibcode=2009A&A...501..297Z }}</ref>
+==Precautions==
+When doing the hardness tests the minimum distance between indentations and the distance from the indentation to the edge of the specimen must be taken into account to avoid interaction between the work-hardened regions and effects of the edge. This minimum distances are different for ISO 6507-1 and ASTM E384 standards.
-<ref name=SIMBAD>{{citation | title=HD 135742 -- Variable Star | work=SIMBAD Astronomical Object Database | url=http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=beta+librae | accessdate=2007-01-22 }}</ref>
+{| class="wikitable" border="1"
+|-
+!   Standard   !! Distance between indentations !! Distance from the center of the indentation to the edge of the specimen
+|-
+| ISO 6507-1 || > 3·d for steel and copper alloys and > 6·d for light metals || 2.5·d for steel and copper alloys and > 3·d for light metals
+|-
+| ASTM E384 || 2.5·d || 2.5·d
+|-
+|}
-<ref name=lang2006>{{citation | first1=Kenneth R. | last1=Lang | title=Astrophysical formulae | volume=1 | series=Astronomy and astrophysics library | edition=3 | publisher=Birkhäuser | year=2006 | isbn=3540296921 | url=http://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 }}. The radius (R<sub>*</sub>) is given by:
+==Estimating tensile strength==
-:<math>\begin{align} 2\cdot R_*
+If HV is expressed in <math>\mbox{kg/mm}^2</math> the [[tensile strength]] (in MPa) of the material can be approximated as:
- & = \frac{(56.8\cdot 0.801\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
- & \approx 9.8\cdot R_{\bigodot}
-\end{align}</math></ref>
-<ref name=mnras389_2_869>{{cite journal | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869–879 | month=September | year=2008 | doi=10.1111/j.1365-2966.2008.13596.x | bibcode=2008MNRAS.389..869E |arxiv = 0806.2878 }}</ref>
+<math>{\sigma_u} \approx {\H_V}*c \approx {\H_V}*{3.33}</math>
-<ref name="uiuc">{{citation | title=Zubeneschamali | first1=James B. | last1=Kaler | publisher=University of Illinois | url=http://www.astro.uiuc.edu/~kaler/sow/zubenes.html | work=Stars | year=2006 | accessdate=2006-07-03 }}</ref>
+where c is a constant determined by geometrical factors usually ranging between 2 and 4. <ref>{{cite web|title=Hardness|url=http://aluminium.matter.org.uk/content/html/eng/default.asp?catid=150&pageid=2144416429}}</ref>
-<ref name="glyphweb">{{citation | title=Zuben Elschemali | work=The Electronic Sky | author=Mark Fisher | year=1999-2006 | url=http://www.glyphweb.com/esky/stars/zubenelschemali.html | accessdate=2009-01-25 }}</ref>
+==Application==
+The [[Vertical stabilizer|fin]] attachment pins and sleeves in the [[Convair CV-240 family|Convair 580]] airliner were specified by the aircraft manufacturer to be hardened to a Vickers Hardness specification of 390HV5, the '5' meaning five [[Kilogram-force|kiloponds]]. However on the aircraft flying [[Partnair Flight 394]] the pins were later found to have been replaced with sub-standard parts, leading to rapid wear and finally loss of the aircraft. On examination, accident investigators found that the sub-standard pins had a hardness value of only some 200-230HV5.<ref>http://www.aibn.no/aviation/reports/1993-02-eng</ref>
-<ref name=lahire1727>{{citation | url=http://www.archive.org/stream/tabulaeastronom00suntgoog#page/n146/mode/2up | first1=Philippe | last1=La Hire | title=Tabulae Astronomicae | year=1727}}, see star table, page 13.</ref>
+== See also ==
+{{multicol}}
+* [[Indentation hardness]]
+* [[Leeb Rebound Hardness Test]]
+* [[Hardness comparison]]
+* [[Knoop hardness test]]
+{{multicol-break}}
+* [[Meyer hardness test]]
+* [[Rockwell scale]]
+* [[Ceramography#Microindention hardness and toughness|Vickers toughness test of ceramics]]
+{{multicol-end}}
-<ref name="Auk">{{citation | title=LIBRA – A Balanced View (page 7 of PDF) | work=Auckland Astronomical Society | url=http://www.astronomy.org.nz/Documents/Journal/journal_200606.pdf | author=AAS | year=2006 | accessdate=2009-01-25 }}</ref>
+== References ==
+===Notes===
+{{reflist}}
+Note 7 is a link to a source that gives conversion formula as Vickers Hardness (HV) ~ 0.3 × yield stress (in MPa) which is wrong as it should be Vickers Hardness (HV) ~ 0.3 × ultimate stress (in MPa)
+===Bibliography===
+* {{cite book
+ | author = Meyers and Chawla
+ | year = 1999
+ | chapter = Section 3.8
+ | title = Mechanical Behavior of Materials
+ | publisher = Prentice Hall, Inc
 }}
+==Further reading==
+*[[ASTM]] E92: Standard method for Vickers hardness of metallic materials (Withdrawn and replaced by E384-10e2)
+*ASTM E384: Standard Test Method for Knoop and Vickers Hardness of Materials
+*[[International Organization for Standardization|ISO]] 6507-1: Metallic materials - Vickers hardness test - Part 1: Test method
+*ISO 6507-2: Metallic materials - Vickers hardness test - Part 2: Verification and calibration of testing machines
+*ISO 6507-3: Metallic materials - Vickers hardness test - Part 3: Calibration of reference blocks
+*ISO 6507-4: Metallic materials - Vickers hardness test - Part 4: Tables of hardness values
 ==External links==
-*{{citation | url=http://www.icoproject.org/star.html | title=Arabic Star Names | work=Islamic Crescents' Observation Project | first1=Moh'd | last1=Odeh | year=1998-2006 | accessdate=2006-07-03 }} – Find more Arabic Star Names and their meanings.
+* [http://www.youtube.com/watch?v=7Z90OZ7C2jI Video on the Vickers hardness test]
+* [http://www.gordonengland.co.uk/hardness/vickers.htm Vickers hardness test]
-{{Stars of Libra}}
+* [http://www.struers.com/default.asp?top_id=5&main_id=25&doc_id=344&target=_self&collapse=1 Conversion table] - Vickers, Brinell, and Rockwell scales
-[[Category:Bayer objects|Librae, Beta]]
+[[Category:Hardness tests]]
-[[Category:B-type main sequence stars]]
-[[Category:Libra (constellation)]]
-[[Category:Stars with proper names]]
-[[ar:الزبان الشمالي]]
+[[de:Härte#Härteprüfung nach Vickers (HV)]]
-[[bg:Зубен Ел Шемали]]
-[[de:Zuben-el-schemali]]
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-[[fa:زبان شمالی]]
-[[fr:Beta Librae]]
-[[ko:주벤에샤마리]]
-[[id:Beta Librae]]
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-[[lb:Zuben-el-schemali (Stär)]]
-[[nl:Zuben Elschemali]]
-[[pl:Zubenelschemali]]
-[[pt:Beta Librae]]
-[[ru:Бета Весов]]
-[[sk:Zubenelschemali]]
-[[tr:Beta Libra]]
-[[zh:氐宿四]]