Metal Hardness Chart: Mohs, HB, HV, HS, HRC

Metal Hardness

The hardness of a metal refers to its ability to resist local deformation, particularly plastic deformation, indentations, or scratches. It’s a measure of the material’s softness or hardness.

There are two main types of metal hardness testing methods: static and dynamic. Static testing methods include Brinell, Rockwell, Vickers, Knoop, Meyer, and Barcol, with Brinell, Rockwell, and Vickers being the most widely used. Dynamic testing methods involve the dynamic and impactful application of test forces.

The measurement of hardness is primarily determined by the depth of the indentation, the projected area of the indentation, or the size of the indentation imprint. For instance, Brinell hardness (HB) is calculated by pressing a certain diameter of hardened steel or hard alloy ball into the tested metal surface under a certain test load, maintaining it for a specified time, then unloading, and measuring the diameter of the indentation on the tested surface.

There are numerous methods to increase metal hardness, including alloying with hard elements in the material, process hardening, grain refinement strengthening, dispersion strengthening, second phase strengthening, heat treatment strengthening (such as quenching, carburizing, nitriding, metal infiltration), and surface strengthening. Additionally, the wear resistance of metal materials can be improved by changing the structural form and altering the crystalline state.

Metals Mohs Hardness Chart

The Mohs hardness is a standard for representing mineral hardness, first proposed in 1822 by German mineralogist Frederich Mohs. It is a standard used in mineralogy or gemology. Mohs hardness is determined by using a diamond pyramid needle to scratch the surface of the tested mineral and measure the depth of the scratch. The depth of this scratch is the Mohs hardness, represented by the symbol HM. It is also used to indicate the hardness of other materials.

The depth of the measured scratch is divided into ten levels to represent hardness (scratch method): talc 1 (smallest hardness), gypsum 2, calcite 3, fluorite 4, apatite 5, orthoclase (feldspar) 6, quartz 7, topaz 8, corundum 9, diamond 10. The hardness of the tested mineral is determined by comparing scratches with the standard minerals in the Mohs hardness tester. Although the measurement of this method is rough, it is convenient and practical. It is often used to measure the hardness of natural minerals.

Hardness values are not absolute hardness values, but values represented in order of hardness.

When applying, compare the hardness by scratching. For example, if a mineral can scratch calcite but not fluorite, its Mohs hardness is 3 to 4, and others are inferred. Mohs hardness is only relative hardness, which is rough. The hardness of talc is 1, diamond is 10, and corundum is 9, but the absolute hardness measured by a microhardness tester is 4192 times that of talc for diamond, and 442 times that of talc for corundum. Mohs hardness is convenient to use and is often used in field operations. For example, the hardness of fingernails is about 2.5, copper coins are 3.5-4, steel knives are 5.5, and glass is 6.5.

In addition to the original list of 1 to 10 kinds of minerals, the hardness values of common metals are listed here for reference.

MetalElementHardness (Mohs)
Carbon(diamond)C10
BoronB9.3
Titanium CarbideTi+C9
Tungsten CarbideW+C9
ChromiumCr8.5
TungstenW7.5
VanadiumV7
RheniumRe7
OsmiumOs7
SiliconSi6.5
RutheniumRu6.5
TantalumTa6.5
IridiumIr6.5
TitaniumTi6
ManganeseMn6
GermaniumGe6
NiobiumNb6
RhodiumRh6
UraniumU6
BerylliumBe6
MolybdenumMo5.5
HafniumHf5.5
CobaltCo5
ZirconiumZr5
PalladiumPd4.75
White GoldAu+Ni+Pd4
SteelFe+C4
IronFe4
NickelNi4
ArsenicAs3.5
PlatinumPt3.5
BrassCu+Zn3
BronzeCu+Sn3
CopperCu3
AntimonySb3
ThoriumTh3
AluminumAl2.75
MagnesiumMg2.5
ZincZn2.5
SilverAg2.5
LanthanumLa2.5
CeriumCe2.5
GoldAu2.5
TelluriumTe2.25
BismuthBi2.25
CadmiumCd2
CalciumCa1.75
GalliumGa1.5
StrontiumSr1.5
TinSn1.5
MercuryHg1.5
LeadPb1.5
BariumBa1.25
IndiumIn1.2
ThalliumTi1.2
LithiumLi1.2
SodiumNa0.5
PotassiumK0.4
RubidiumRb0.3
CaesiumCs0.2

Metal Material Hardness Chart

No.Material CodeStrength GradeHardness Value(HB)
011Cr13440(45)197~229
355187~229
021Cr12Mo550229~255
450197~229
03Cr11MoV490(50)217~248
390192~241
590235~269
04Cr12WMoV590235~269
690269~302
052Cr12NiMoWV760293~331
06ZG20CrMoV310140~201
0725Cr2MoVA590241~277
735269~302
0830Cr2MoV440179~229
590241~277
735269~302
0938CrMoAl590241~277
685277~302
785293~321
10A3Hardness after Nitriding Component Normalizing<131
1115#<143
1225#<170
13ZG25<170
1420CrA<179
1512CrNi3A<252
162Cr13490217~248
590235~269
172Cr12NiW1Mo1V735285~302
180Cr17Ni4Cu4Nb590262~302
760277~311
19Cr5Mo/248~302
20GH132(GBn181-82)/284~349
21GH136(GBn181-82)/298~390
22R-26550262~331
233Cr13590235~269
685269~302
233Cr13785286~321
241Cr18Ni9Ti205(225)≦187
250Cr18Ni9205≦187
261Cr18Ni9205≦187
27Cr15Ni3Bw3Ti390207~255
2834CrMo1A490(590)/
2930Cr2MoV590241~277
690256~287
735269~302
3034CrNi3Mo590220~260
690240~282
735255~284
785271~298
3130Cr2Ni4MoV550207~262
690241~302
760262~321
830285~341
3215CrMoA245131~163
490207~241
3315Cr1Mo275≦207
3412Cr1MoVA245131~163
3512Cr2Mo1275≦197
315≦207
3615Cr1Mo1VA325146~196
3725#235(215)110~170
3830#265≦187
3935#265156~217
255140~187
235121~187
4045#295162~217
285149~217
440197~229
345217~255
4115CrMoA245131~163
490207~241
4220MnMo350149~217
4340CrNi3MoA550207~262
690241~302
4415CrMoA490207~241
4540CrA390192~223
4540CrA490217~235
590241~277
685269~302
4640CrNi2MoA540207~269
640248~277
785269~321
4735CrMoA490217~255
590241~277
4840CrNiMoA690255~293
4920Cr1Mo1VtiB690255~293
5030Cr1Mo1V590241~277
5130Cr1Mo1V690255~285
MaterialsReference Standards and Requirements(HB)Control Scope(HB)Note
210CASTM A210,≤179130~179 
T1a, 20MoG, STBA12, 15Mo3ASTM A209,≤153125~153 
T2, T11, T12, T21, T22, 10CrMo910ASTM A213,≤163120~163 
P2, P11, P12, /P21, P22, 10CrMo910 125~179 
P2, P11, P12, /P21P22, 10CrMo910 type pipe fittings 130~197The lower limit of the weld seam must not be less than that of the base material,upper limit≤241
T23ASTM A213,≤220150~220 
12Cr2MoWVTiB(G102) 150~220 
T24ASTM A213,≤250180~250 
T/P91, T/P92, T911, T/P122ASTM A213,≤250ASTM A335,≤250180~250The hardness of “P” type pipes refers to that of “T” type pipes.
(T/P91, T/P92, T911, T/P122)Weld Seam 180~270 
WB36ASME code case2353,≤252180~252The weld seam must not be less hard than the base material.
A515, A106B, A106C, A672 B70 type pipe fittings 130~197The lower limit of the weld seam must not be less than the base material, with the upper limit≤241.
12CrMoGB3077,≤179120~179 
15CrMoJB4726,118~180(Rm:440~610)JB4726,115~178(Rm:430~600)118~180115~178 
12Cr1MoVGB3077,≤179135~179 
15Cr1Mo1V 135~180 
F2(Forged or Rolled Pipe Fittings, Valves, and Components)ASTM A182,143~192143~192 
F11,Class 1ASTM A182,121~174121~174 
F11,Class 2ASTM A182,143~207143~207 
F11,Class 3ASTM A182,156~207156~207 
F12,Class 1ASTM A182,121~174121~174 
F12,Class 2ASTM A182,143~207143~207 
F22,Class 1ASTM A182, ≤170130~170 
F22,Class 3ASTM A182,156~207156~207 
F91ASTM A182, ≤248175~248 
F92ASTM A182, ≤269180~269 
F911ASTM A182, 187~248187~248 
F122ASTM A182, ≤250177~250 
20 Pressure Vessel Carbon Steel and Low Alloy Steel ForgingsJB4726,106~159106~159 
35 (Note: The Rm in the table refers to the tensile strength of the material, measured in MPa.)JB4726,136~200(Rm:510~670)JB4726,130~190(Rm:490~640)136~200130~190 
16MnJB4726,121~178(Rm:450~600)121~178 
20MnMoJB4726,156~208(Rm:530~700)JB4726,136~201(Rm:510~680)JB4726,130~196(Rm:490~660)156~208136~201130~196 
35CrMoJB4726,185~235(Rm:620~790)JB4726,180~223(Rm:610~780)185~235180~223 
0Cr18Ni90Cr17Ni12Mo2JB4728,139~187(Rm:520)JB4728,131~187(Rm:490)139~187131~187Stainless Steel Forgings for Pressure Vessels
1Cr18Ni9GB1220 ≤187140~187 
0Cr17Ni12Mo2GB1220 ≤187140~187 
0Cr18Ni11NbGB1220 ≤187140~187 
TP304H, TP316H, TP347HASTM A213,≤192140~192 
1Cr13 192~211Moving Blades
2Cr13 212~277Moving Blades
1Cr11MoV 212~277Moving Blades
1Cr12MoWV 229~311Moving Blades
ZG20CrMoJB/T 7024,135~180135~180 
ZG15Cr1MoJB/T 7024,140~220140~220 
ZG15Cr2Mo1JB/T 7024,140~220140~220 
ZG20CrMoVJB/T 7024,140~220140~220 
ZG15Cr1Mo1VJB/T 7024,140~220140~220 
35DL/T439,146~196146~196Bolt
45DL/T439,187~229187~229Bolt
20CrMoDL/T439,197~241197~241Bolt
35CrMoDL/T439,241~285241~285Bolt(Dia.>50mm)
35CrMoDL/T439,255~311255~311Bolt(Dia.≤50mm)
42CrMoDL/T439,248~311248~311Bolt(Dia.>65mm)
42CrMoDL/T439,255~321255~321Bolt(Dia.≤65mm)
25Cr2MoVDL/T439,248~293248~293Bolt
25Cr2Mo1VDL/T439,248~293248~293Bolt
20Cr1Mo1V1DL/T439,248~293248~293Bolt
20Cr1Mo1VTiBDL/T439,255~293255~293Bolt
20Cr1Mo1VNbTiBDL/T439,252~302252~302Bolt
20Cr12NiMoWV(C422)DL/T439,277~331277~331Bolt
2Cr12NiW1Mo1VEastern Steam Turbine Factory Standard291~321Bolt
2Cr11Mo1NiWVNbNEastern Steam Turbine Factory Standard290~321Bolt
45Cr1MoVEastern Steam Turbine Factory Standard248~293Bolt
R-26(Ni-Cr-Co Alloy)DL/T439,262~331262~331Bolt
GH445DL/T439,262~331262~331Bolt
ZG20CrMoJB/T7024,135~180135~180Cylinder
ZG15Cr1Mo, ZG15Cr2MoZG20Cr1MoV, ZG15Cr1Mo1VJB/T7024,140~220140~220Cylinder

Non-ferrous & Ferrous Metal Hardness Chart

1. Non-ferrous Metal Hardness Chart

Non-ferrous Metal HardnessTensile strength
δb/MPa
RockwellSurface RockwellVickersBrinell
(F/D2=30) 
HRCHRAHR15NHR30NHR45NHVHBSHBWMSCr.SCr-V.SCrNi.SCr-Mo.SCr-Ni-Mo .SCrMnSi.SUHSSS.S
20.060.268.840.719.2226225225774742736782747/781/740
20.560.469.041.219.8228227227784751744787753/788/749
21.060.769.341.720.4230229229793760753792760/794/758
21.561.069.542.221.0233232232803769761797767/801/767
22.061.269.842.621.5235234234813779770803774/809/777
22.561.570.043.122.1238237237823788779809781/816/786
23.061.770.343.622.724l240240833798788815789/824/796
23.562.070.644.023.3244242242843808797822797/832/806
24.062.270.844.523.9247245245854818807829805/840/816
24.562.571.145.024.5250248248864828816836813/848/826
25.062.871.445.525.1253251251875838826843822/856/837
25.563.071.645.925.7256254254886848837851831850865/847
26.063.371.946.426.3259257257897859847859840859874/858
26.563.572.246.926.9262260260908870858867850869883/868
27.063.872.447.327.5266263263919880869876860879893/879
27.564.072.747.828.1269266266930891880885870890902/890
28.064.373.048.328.7273269269942902892894880901912/901
28.564.673.348.729.3276273273954914903904891912922/913
29.064.873.549.229.9280276276965925915914902923933/924
29.565.173.849.730.5284280280977937928924913935943/936
30.065.374.150.231.1288283283989948940935924947954/947
30.565.674.450.631.72922872871002960953946936959965/959
31.065.874.751.132.329629l29l1014972966957948972977/971
31.566.174.951.632.93002942941027984980969961985989/983
32.066.475.252.033.530429829810399969939819749991001/996
32.566.675.552.534.130830230210521009100799498710121013/1008
33.066.975.853.034.73133063061065102210221007100110271026/1021
33.567.176.153.435.33173103101078103410361020101510411039/1034
34.067.476.453.935.932l3143141092104810511034102910561052/1047
34.567.776.754.436.53263183181105106110671048104310711066/1060
35.067.977.054.837.033l3233231119107410821063105810871079/1074
35.568.277.255.337.63353273271133108810981078107411031094/1087
36.068.477.555.838.23403323321147110211141093109011191108/1101
36.568.777.856.238.83453363361162111611311109110611361123/1116
37.069.078.156.739.43503413411177113111481125112211531139/1130
37.569.278.457.240.03553453451192114611651142113911711155/1145
38.069.578.757.640.63603503501207116111831159115711891171/1161
38.569.779.058.141.2365355355122211761201117711741207118711701176
39.070.079.358.641.837l360360123811921219119511921226120411951193
39.570.379.659.042.4376365365125412081238121412111245122212191209
40.070.579.959.543.0381370370127112251257123312301265124012431226
40.570.880.260.043.6387375375128812421276125212491285125812671244
41.071.180.560.444.2393380381130512601296127312691306127712901262
41.571.380.860.944.8398385386132212781317129312891327129613131280
42.071.681.161.345.440439l392134012961337131413101348131613361299
42.571.881.461.845.9410396397135913151358133613311370133613591319
43.072.181.762.346.541640l403137813351380135813531392135713811339
43.572.482.062.747.1422407409139713551401138013751415137814041361
44.072.682.363.247.7428413415141713761424140413971439140014271383
44.572.982.663.648.3435418422143813981446142714201462142214501405
45.073.282.964.148.944l424428145914201469145114441487144514731429
45.573.483.264.649.5448430435148114441493147614681512146914961453
46.073.783.565.050.145443644l150314681517150214921537149315201479
46.573.983.765.550.746l442448152614931541152715171563151715441505
47.074.284.065.951.2468449455155015191566155415421589154315691533
47.574.584.366.451.8475/463157515461591158115681616156915941562
48.074.784.666.852.4482/470160015741617160815951643159516201592
48.575.084.967.353.0489/478162616031643163616221671162316461623
49.075.385.267.753.6497/486165316331670166516491699165116741655
49.575.585.568.254.2504/494168116651697169516771728167917021689
50.075.885.768.654.7512502502171016981724172417061758170917311725
50.576.186.069.155.3520510510/1732175217551735178817391761/
51.076.386.369.555.9527518518/1768178017861764181917701792/
51.576.686.670.056.5535527527/1806180918181794185018011824/
52.076.986.870.457.1544535535/1845183918501825188118341857/
52.577.187.170.957.6552544544//186918831856191418671892/
53.077.487.471.358.2561552552//189919171888194719011929/
53.577.787.671.858.856956l56l//19301951//19361966/
54.077.987.972.259.4578569569//19611986//19712006/
54.578.288.172.659.9587577577//19932022//20082047/
55.078.588.473.160.5596585585//20262058//20452090/
55.578.788.673.561.1606593593///////2135/
56.079.088.973.961.7615601601///////2181/
56.579.389.174.462.2625608608///////2230/
57.079.589.474.862.8635616616///////2281/
57.579.889,675.263.4645622622///////2334/
58.080.189.875.663.9655628628///////2390/
58.580.390.076.164.5666634634///////2448/
59.080.690.276.565.1676639639///////2509/
59.580.990.476.965.6687643643///////2572/
60.081.290.677.366.2698647647/////////
60.581.490.877.766.8710650650/////////
61.081.791.078.167.372l///////////
61.582.091.278.667.9733///////////
62.082.291.479.068.4745///////////
62.582.591.579.469.0757///////////
63.082.891.779.869.5770///////////
63.583.191.880.270.1782///////////
64.083.391.980.670.6795///////////
64.583.692.181.071.2809///////////
65.083.992.281.371.1822///////////
65.584.1///836///////////
66.084.4///850///////////
66.584.7///865///////////
67.085.0///879///////////
67.585.2///894///////////
68.085.5///909///////////

2. Ferrous Metal Hardness Chart

The following data is mainly applicable to low-carbon steel (mild steel).

Ferrous Metal HardnessTensile strength
RockwellSurface RockwellVickersBrinell HBS
HRBHR15THR30THR45THVF/D2=10F/D2=10MPa
60.080.456.130.4105102/375
60.580.556.430.9105102/377
61.080.756.731.4106103/379
61.580.857.131.9107103/381
62.080.957.432.4108104/382
62.581.157.732.9108104/384
63.081.258.033.5109105/386
63.581.458.334.0110105/388
64.081.558.734.5110106/390
64.581.659.035.011l106/393
65.081.859.335.5112107/395
65.581.959.636.1113107/397
66.082.159.936.6114108/399
66.582.260.337.1115108/402
67.082.360.637.6115109/404
67.582.560.938.1116110/407
68.082.661.238.6117110/409
68.582.761.539.2118111/412
69.082.961.939.7119112/415
69.583.062.240.2120112/418
70.083.262.540.712l113/42l
70.583.362.841.2122114/424
71.083.463.141.7123115/427
71.583.663.542.3124115/430
72.083.763.842.8125116/433
72.583.964.143.3126117/437
73.084.064.443.8128118/440
73.584.164.744.3129119/444
74.084.365.144.8130120/447
74.584.465.445.413l12l/451
75.084.565.745.9132122152455
75.584.766.046.4134123155459
76.084.866.346.9135124156463
76.585.066.647.4136125158467
77.085.167.047.9138126159471
77.585.267.348.513912716l475
78.085.467.649.0140128163480
78.585.567.949.5142129164484
79.085.768.250.0143130166489
79.585.868.650.5145132168493
80.085.968.951.0146133170498
80.586.169.251.6148134172503
81.086.269.552.1149136174508
81.586.369.852.6151137/513
82.086.570.253.1152138/518
82.586.670.553.6154140/523
83.086.870.854.1156//529
83.586.971.154.7157//534
84.087.071.455.2159//540
84.587.271.855.716l//546
85.087.372.156.2163//551
85.587.572.456.7165//557
86.087.672.757.2166//563
86.587.773.057.8168//570
87.087.973.458.3170//576
87.588.073.758.8172//582
88.088.174.059.3174//589
88.588.374.359.8176//596
89.088.474.660.3178//603
89.588.675.060.9180//609
90.088.775.361.4183/176617
90.588.875.661.9185/178624
91.089.075.962.4187/18063l
91.589.176.262.9189/182639
92.089.376.663.4191/184646
92.589.476.964.0194/187654
93.089.577.264.5196/189662
93.589.777.565.0199/192670
94.089.877.865.5201/195678
94.589.978.266.0203/197686
95.590.178.566.5206/200695
95.090.278.867.1208/203703
96.090.479.167.6211/206712
96.590.579.468.1214/209721
97.090.679.868.6216/212730
97.590.880.169.1219/215739
98.090.980.469.6222/218749
98.591.180.770.2225/222758
99.091.281.070.7227/226768
99.591.381.471.2230/229778
100.091.581.771.7233/232788

Related reading: Metal Hardness Comparison Chart: HV, HB, HRC

Commonly Used Hardness

Brinell Hardness

The Brinell hardness test uses a ball made of hardened steel or a hard alloy with a diameter of D as the indenter.

A specified test force F is applied to the surface of the material being tested, and after a designated hold time, the test force is removed, leaving an indentation with a diameter of d.

The Brinell hardness value is calculated by dividing the test force by the surface area of the indentation. The symbol for the Brinell hardness value is represented as HBS or HBW.

Brinell Hardness

The difference between HBS and HBW lies in the type of indenter used.

HBS indicates the use of a hardened steel ball as the indenter and is used to determine the Brinell hardness of materials with a value less than 450, such as mild steel, gray cast iron, and non-ferrous metals.

HBW, on the other hand, refers to the use of a hard alloy ball as the indenter and is used to measure the Brinell hardness of materials with a value below 650.

Even when the same material and experimental conditions are used, the results of the two tests may vary, with the HBW value typically being higher than the HBS value, and there is no exact quantitative rule to follow.

HBW Formula

In 2003, China adopted international standards and discontinued the use of steel ball indenters in favor of hard alloy ball heads.

As a result, HBS was no longer used and all Brinell hardness values are now represented by HBW.

Although HBW is often simply referred to as HB, references to HBS may still be found in literature.

The Brinell hardness measurement method is suitable for testing materials such as cast iron, non-ferrous alloys, and various steels that have undergone annealing or quenching and tempering processes.

However, it is not suitable for testing samples or workpieces that are too hard, too small, too thin, or do not allow for large indentations on the surface.

Rockwell Hardness

The Vickers hardness test uses either a diamond cone with a 120-degree cone apex angle or a hardened steel ball with a diameter of Ø1.588mm or Ø3.176mm as the indenter, along with a specified load.

The sample is subjected to an initial load of 10kgf and a total load of 60, 100, or 150kgf.

After the total load is applied, the hardness is determined by the difference in indentation depth when the main load is removed while retaining the initial load and the indentation depth under the initial load.

Rockwell Hardness

The Rockwell hardness test uses three different test forces and three different indenters, resulting in a total of nine possible combinations and corresponding Rockwell hardness scales.

These nine scales are suitable for a wide range of commonly used metal materials.

The three most commonly used Rockwell hardness scales are HRA, HRB, and HRC, with HRC being the most widely utilized.

Table of commonly used Rockwell hardness test specifications

Hardness symbolIndenter typeTotal test force
F/N(kgf)
Hardness rangeApplications
HRA120°diamond cone588.4(60)20~88Hard alloy, carbide, shallow case hardening steel and etc.
HRBØ1.588mm Quenched steel ball980.7(100)20~100Annealed or normalized steel, aluminum alloy, copper alloy, cast iron
HRC120°diamond cone1471(150)20~70Hardened steel, quenched and tempered steel, deep case hardening steel

The Rockwell hardness test is appropriate for hardness values ranging from 20-70HRC. If the hardness of the sample is less than 20HRC, it is recommended to use the HRB scale as the sensitivity of the indenter decreases with increased pressure on the conical part.

However, if the hardness of the sample is greater than 67HRC, it is advised to use the HRA scale as the pressure on the tip of the indenter may become too high and result in damage to the diamond and reduced life of the indenter.

The Rockwell hardness test is known for its ease, speed, and minimal indentation, making it ideal for testing the surface of finished products and harder, thinner workpieces.

However, due to the small indentation, the hardness value may fluctuate greatly for materials with uneven structures and hardness, making it less accurate than the Brinell hardness test.

The Rockwell hardness test is commonly used to determine the hardness of materials such as steel, non-ferrous metals, and cemented carbides.

Vickers Hardness

Vickers Hardness

The principle behind the Vickers hardness measurement is similar to that of the Brinell hardness test.

A diamond pyramid-shaped indenter with an angle of 136° is used to apply a specified test force, F, onto the surface of the material being tested.

After a specified holding time, the test force is removed, and the hardness value is calculated as the average pressure on the unit surface area of the regular pyramid-shaped indentation, with the symbol HV.

HV Formula

The Vickers hardness measurement has a wide range, and it can measure materials with a hardness ranging from 10 to 1000 HV. The indentation is small in size.

This measurement method is commonly used to measure thin materials and surface-hardened layers created through carburizing and nitriding.

Leeb Hardness

The Leeb Hardness Test uses a device equipped with a tungsten carbide ball to impact the surface of the test piece, which then rebounds. The speed of the rebound is affected by the hardness of the material being tested.

A permanent magnetic material is installed on the impact device, which produces an electromagnetic signal proportional to the speed of the impact body’s movement. This signal is then converted into a Leeb hardness value by an electronic circuit, represented by the symbol HL.

The Leeb Hardness Tester is a handheld device that does not require a workbench. Its hardness sensor is compact and can be easily operated by hand, making it suitable for testing large, heavy, or complex geometries.

One of the key benefits of the Leeb Hardness Test is that it results in only light surface damage, making it an ideal option for non-destructive testing. It also provides a unique hardness test for all directions, narrow spaces, and special parts.

Hardness Test

The Brinell hardness test measures the hardness of a sample by pressing a steel ball or diamond cone into the sample’s surface and measuring the depth of the indentation. This method is suitable for determining the hardness of materials such as annealed, normalized, quenched and tempered steel, cast iron, and non-ferrous metals.

The Rockwell hardness test uses specific procedures and smaller indenters, such as diamonds, to measure hardness, making it suitable for a wide range of materials.

The Vickers hardness test retains the advantages of both the Brinell and Rockwell tests, capable of measuring materials ranging from extremely soft to extremely hard, and their results can be compared.

The specifics of the advantages and disadvantages of the Knoop hardness test are not detailed in the information I found, but it is one of the static test methods, on par with Brinell, Rockwell, and Vickers.

The Webster hardness tester is primarily used to check the mechanical properties of aluminum alloy profiles, but it’s also suitable for materials like copper, brass, and mild steel.

The Barcol hardness tester is a type of indentation hardness tester. The specifics of its advantages and disadvantages are not explicitly stated in the information I found.

Each hardness testing method has its characteristics and range of applications:

  • The Brinell hardness test is suitable for various materials, especially annealed, normalized, quenched and tempered steel, cast iron, and non-ferrous metals.
  • The Rockwell hardness test is suitable for a wide range of materials, using a smaller indenter for measurements.
  • The Vickers hardness test combines the advantages of both the Brinell and Rockwell tests, suitable for materials from extremely soft to extremely hard, and their results can be compared.
  • The Knoop hardness test, as one of the static test methods, is suitable for various materials, but further understanding of its specifics is needed.
  • The Webster hardness tester is particularly suitable for checking the mechanical properties of aluminum alloy profiles, but can also be used for other materials.
  • The Barcol hardness tester, as an indentation hardness tester, holds a place in material hardness testing.

Hardness Testers

  • Micro Vickers hardness testing machine

HM series:

Micro Vickers hardness testing machine

  • Vickers hardness testing machine
    HV series:
Vickers hardness testing machine

  • Rockwell hardness testing machine
    HR series:
Rockwell hardness testing machine

  • Portable Leeb hardness tester
    HH series:
Portable Leeb hardness tester

How can the hardness of metal materials be improved through heat treatment?

The hardness of metal materials can be enhanced through heat treatment using several methods, including:

Carburizing and Nitriding: These chemical heat treatment methods involve the infusion of carbon atoms (carburizing) or active nitrogen atoms (nitriding) into the surface layer of the metal. This increases the carbon content or abrasion resistance of the metal surface layer, thus enhancing hardness and wear resistance. Commonly used carburizing medium is charcoal, while nitriding utilizes active nitrogen atoms decomposed from ammonia gas when heated.

Quenching: For general medium carbon steel and high carbon steel, the hardness can be improved through quenching. Quenching is a common heat treatment method that involves heating the steel to an appropriate temperature and then cooling it quickly to achieve higher hardness.

Altering Grain Size and Phase Composition: Heat treatment affects hardness by altering the grain size and phase composition of the metal material. This can be achieved through mechanisms such as grain boundary solution strengthening, crystal solution strengthening, and phase transformation strengthening.

Coating Technology: Using coating technology during the heat treatment process of metal materials can prevent significant damage to the metal structure while achieving optimal hardness, ensuring a significant improvement in application results.

Reorganizing the Organizational Structure: Heat treatment processing can enhance material uniformity and hardness by reorganizing the organizational structure and reducing or eliminating non-uniformity. This method can be implemented in various ways depending on specific needs.

Forming a Protective Layer: Forming a thin protective layer on the surface of metal materials alters the original structure of the metal. Compared to traditional quenching methods, this approach effectively increases the surface hardness of the metal and offers the advantage of easy operation.

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Shane
Author

Shane

Founder of MachineMFG

As the founder of MachineMFG, I have dedicated over a decade of my career to the metalworking industry. My extensive experience has allowed me to become an expert in the fields of sheet metal fabrication, machining, mechanical engineering, and machine tools for metals. I am constantly thinking, reading, and writing about these subjects, constantly striving to stay at the forefront of my field. Let my knowledge and expertise be an asset to your business.

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