Conversions All values, except WMN, are consistent with ASTM E140 Tables 1 and 2, and ASTM A370 Tables 3A and 3B, where applicable. WMN or Wilson Microfi cial Numbers were developed by Wilson Instruments in the Wilson Standards laboratory and are not derived from ASTM.

Cylindrical Corrections Values are consistent with ASTM E18 Table 6,7,13, and 14Hardness vs. Minimum Thickness Values are consistent with ASTM E18 Tables 4, 5, 11, and 12 except for D and G scale values, which are obtained from indentation hardness testing by Vincent E. Lysaght.

Rockwell Superfi cial Knoop Brinell TensileStrength

Micro-fi cial

B F G A E H K 15-T 30-T 45-T HK HB HBHV KSI WMN

100 kg

1/16”ball

60 kg

1/16” ball

150 kg

1/16”ball

60 kg

Brale

100 kg

1/8”ball

60 kg

1/8” ball

150 kg

1/8”ball

15kg

1/16”ball

30 kg

1/16” ball

45kg

1/16”ball

500 gmandover

500 kg10 mm ball

3000 kg

10 kg

1000lbs/sq in

1000 gm

1009998

82.581.079.0

61.560.960.2

93.192.892.5

83.182.581.8

72.971.970.9

251246241

201195189

240234228

116114109

730725719

979695

77.576.074.0

59.558.958.3

92.191.891.5

81.180.479.8

69.968.967.9

236231226

184179175

222216210

104102100

713707701

949392

72.571.069.0

57.657.056.4

NA100

91.290.890.5

79.178.477.8

66.965.964.8

221216211

171167163

205200195

989492

696690684

919089

67.566.064.0

55.855.254.6

99.598.598.0

90.289.989.5

77.176.475.8

63.862.861.8

206201196

160157154

190185180

908988

679674668

888786

62.561.059.0

54.053.452.8

97.096.595.5

89.288.988.6

75.174.473.8

60.859.858.8

192188184

151148145

176172169

868483

662656651

858483

57.556.054.0

52.351.751.1

94.594.093.0

88.287.987.6

73.172.471.8

57.856.855.8

180176173

142140137

165162159

828180

646640634

828180

52.551.049.0

50.650.049.5

92.091.090.5

87.386.986.6

71.170.469.7

54.853.852.8

170167164

135133130

156153150

777372

629624618

797877

47.546.044.0

48.948.447.9

89.588.588.0

86.386.085.6

69.168.467.7

51.850.849.8

161158155

128126124

147144141

706968

612607602

767574

NA99.699.1

42.541.039.0

47.346.846.3

87.086.085.0

85.385.084.7

67.166.465.7

48.847.846.8

152150147

122120118

139137135

676665

596592587

737271

98.598.097.4

37.536.034.5

45.845.344.8

NA100

84.583.582.5

84.384.083.7

65.164.463.7

45.844.843.8

145143141

116114112

132130127

646362

581576571

706968

96.896.295.6

32.531.029.5

44.343.843.3

99.599.098.0

81.581.080.0

83.483.082.7

63.162.461.7

42.841.840.8

139137135

110109107

125123121

616059

566561556

676665

95.194.593.9

28.026.525.0

42.842.341.8

97.597.096.0

79.078.077.5

82.482.181.8

61.060.459.7

39.838.737.7

133131129

106104102

119117116

585756

551546542

646362

93.492.892.2

23.522.020.5

41.440.940.4

95.595.094.5

76.575.574.5

81.481.180.8

59.058.457.7

36.735.734.7

127125124

1019998

114112110

NA 537532527

616059

91.791.190.5

19.017.516.0

40.039.539.0

93.593.092.5

74.073.072.0

80.580.179.8

57.056.455.7

33.732.731.7

122120118

969594

108107106

522517512

585756

90.089.488.8

14.513.011.5

38.638.137.7

92.091.090.5

71.070.569.5

79.579.278.8

55.054.453.7

30.729.728.7

117115114

929190

104103101

507502497

555453

88.287.787.1

10.08.57.0

37.236.836.3

90.089.589.0

68.568.067.0

78.578.277.9

53.052.451.7

27.726.725.7

112111110

898786

100NA

492487482

525150

86.586.085.4

5.54.02.5

35.935.535.0

88.087.587.0

66.065.064.5

77.577.276.9

51.050.349.7

24.723.722.7

109108107

858483

477472468

494847

84.884.383.7

NA 34.634.133.7

86.585.585.0

63.562.561.5

76.676.275.9

49.048.347.7

21.720.719.7

106105104

828180

463458453

464544

83.182.682.0

33.332.932.4

84.584.083.5

61.060.059.0

75.675.374.9

47.046.345.7

18.717.716.7

103102101

807978

448444439

434241

81.480.880.3

32.031.631.2

82.582.081.5

58.057.556.5

74.674.374.0

45.044.343.7

15.714.713.6

1009998

777675

435430426

403938

79.779.178.6

30.730.329.9

81.080.079.5

55.554.554.0

73.673.373.0

43.042.341.6

12.611.610.6

979695

757473

422417413

373635

78.077.476.9

29.529.128.7

79.078.578.0

NA10099.5

53.052.051.5

72.772.372.0

41.040.339.6

9.68.67.6

949392

727271

409404401

343332

76.375.775.2

28.227.827.4

77.076.576.0

99.098.898.5

50.549.548.5

71.771.471.0

39.038.337.6

6.65.64.6

919089

706969

396392388

313029

74.674.073.5

27.026.626.0

75.575.074.0

98.097.897.5

48.047.046.0

70.770.470.0

37.036.335.6

3.62.61.0

888787

686766

384380376

282726

73.072.572.0

25.525.024.5

73.573.072.5

97.096.596.3

45.044.543.5

69.369.569.0

34.534.033.0

NA 868584

666565

372369365

252423

71.070.570.0

24.324.023.5

72.071.070.5

96.095.595.3

42.541.541.0

68.868.568.0

32.532.031.0

838282

646463

361357353

222120

69.569.068.5

23.022.522.0

70.069.568.5

95.094.594.3

40.039.038.0

67.867.567.3

30.529.529.0

818180

626261

350346343

191817

68.067.066.5

21.521.321.0

68.067.567.0

94.093.593.0

37.536.535.5

67.066.566.3

28.527.527.0

797878

616060

339335332

161514

66.065.565.0

20.520.0NA

66.565.565.0

92.892.592.0

35.034.033.0

66.065.565.3

26.025.525.0

777675

595959

329325322

131211

64.564.063.5

64.564.063.5

91.891.591.0

32.031.530.5

65.064.564.3

24.023.523.0

757473

585857

318314311

1098

63.062.061.5

62.562.061.5

90.590.390.0

29.529.028.0

64.063.863.5

22.021.520.5

727171

575756

308304300

765

61.060.560.0

61.060.560.0

89.589.389.0

27.026.025.5

63.062.862.5

20.019.518.5

706969

565555

297293289

432

59.559.058.0

59.058.558.0

88.588.087.8

24.523.523.0

62.061.861.5

18.017.016.5

696868

555454

286283279

10

57.557.0

57.557.0

87.587.0

22.021.0

61.060.5

16.015.0

6363

5453

276272

Soft Steel, Grey and Malleable Cast Iron and Most Non-Ferrous Metals Scales C, D, A

Brale Diamond IndenterDiameter of Specimen - inches (mm)

ObservedReading

1/8(3.2)

1/4(6.4)

3/8(10)

1/2(13)

5/8(16)

3/4(19)

7/8(22)

1(25)

1-1/4(32)

1-1/2(38)

908580

NA 0.50.50.5

00.50.5

00.50.5

00

0.5

00

0.5

000

000

000

000

757065

1.01.01.5

0.51.01.0

0.50.51.0

0.50.50.5

0.50.50.5

0.50.50.5

00.50.5

000

000

605550

1.52.02.5

1.01.52.0

1.01.01.5

0.51.01.0

0.50.51.0

0.50.50.5

0.50.50.5

00.50.5

00

0.5454035

3.03.54.0

2.02.53.0

1.52.02.0

1.01.51.5

1.01.01.5

1.01.01.0

0.51.01.0

0.50.50.5

0.50.50.5

302520

5.05.56.0

3.54.04.5

2.53.03.5

2.02.52.5

1.52.02.0

1.51.51.5

1.01.01.5

1.01.01.0

0.51.01.0

Scales B, F, G1/16-in Ball Indenter

Diameter of Specimen - inches (mm)

ObservedReading

1/8(3.2)

1/4(6.4)

3/8(10)

1/2(13)

5/8(16)

3/4(19)

7/8(22)

1(25)

1-1/4(32)

1-1/2(38)

1009080

NA 3.54.05.0

2.53.03.5

1.52.02.5

1.51.52.0

1.01.51.5

1.01.51.5

0.51.01.5

NA NA

706050

6.07.08.0

4.05.05.5

3.03.54.0

2.53.03.5

2.02.53.0

2.02.02.5

1.52.02.0

403020

9.010.011.0

6.06.57.5

4.55.05.5

4.04.54.5

3.03.54.0

2.53.03.5

2.52.53.0

100

12.012.5

8.08.5

6.06.5

5.05.5

4.04.5

3.53.5

3.03.0

Scales 15-N, 30-N, 45-NN Brale Diamond Indenter

Diameter of Specimen - inches (mm)

ObservedReading

1/8(3.2)

1/4(6.4)

3/8(10)

1/2(13)

5/8(16)

3/4(19)

7/8(22)

1(25)

1-1/4(32)

1-1/2(38)

908580

00.51.0

00.50.5

00.50.5

00.50.5

00

0.5

000

000

000

NA NA

757065

1.52.02.5

1.01.01.5

0.51.01.0

0.50.50.5

0.50.50.5

0.50.50.5

00.50.5

00.50.5

605550

3.03.53.5

1.52.02.0

1.01.51.5

1.01.01.0

1.01.01.0

0.50.51.0

0.50.51.0

0.50.50.5

454035

4.04.55.0

2.02.52.5

1.51.52.0

1.01.51.5

1.01.01.0

1.01.01.0

1.01.01.0

1.01.01.0

302520

5.55.56.0

3.03.03.0

2.02.02.0

1.51.51.5

1.51.51.5

1.01.51.5

1.01.51.5

1.01.01.5

Scales 15-T, 30-T, 45-T1/16-in Ball Indenter

Diameter of Specimen - inches (mm)

ObservedReading

1/8(3.2)

1/4(6.4)

3/8(10)

1/2(13)

5/8(16)

3/4(19)

7/8(22)

1(25)

1-1/4(32)

1-1/2(38)

908070

1.53.05.0

1.02.03.5

1.01.52.5

0.51.52.0

0.51.01.5

0.51.01.0

0.51.01.0

0.50.51.0

NA NA

605040

6.58.5

10.0

4.55.56.5

3.04.04.5

2.53.03.5

2.02.53.0

1.52.02.5

1.52.02.0

1.51.52.0

3020

11.513.0

7.59.0

5.06.0

3.54.5

3.54.5

2.53.0

2.02.0

2.02.0

Cylindrical Correction Chart 53Cylindrical work corrections to be added to observed

Rockwell number for scales indicated

Rockwell Superfi cial Vickers Knoop Brinell TensileStrength

Micro-fi cial

C A D G 15-N 30-N 45-N HV HK HB KSI WMN

150 kg

Brale

60 kg

Brale

100 kg

Brale

150 kg

1/16” ball

15 kg N

Brale

30 kg N

Brale

45 kg N

Brale

10 kg

500 gmand over

3000 kg10 mm ball

1000 lbs/sq in

1000 gm

807978

92.091.591.0

86.585.584.5

96.596.396.0

92.091.591.0

87.086.585.5

186517871710

---

---

777675

90.590.089.5

84.083.082.5

95.895.595.3

90.590.089.0

84.583.582.5

163315561478

---

---

747372

89.088.588.0

81.581.080.0

95.094.894.5

88.588.087.0

81.580.579.5

140013231245

---

---

717069

87.086.586.0

79.578.578.0

94.394.093.5

86.586.085.0

78.577.576.5

116010761004

-972946

-953949

686766

85.685.084.5

76.976.175.4

93.292.992.5

84.483.682.8

75.474.273.3

940900865

920895870 NA

945942938

656463

83.983.482.8

74.573.873.0

92.291.891.4

81.981.180.1

72.071.069.9

832800772

846822799

739722706

934930926

626160

82.381.881.2

72.271.570.7

91.190.790.2

79.378.477.5

68.867.766.6

746720697

776754732

688670654 NA

922917913

595857

80.780.179.6

69.969.268.5

89.889.388.9

76.675.774.8

65.564.363.2

674653633

710690670

634615595

351338325

909904900

565554

79.078.578.0

67.766.966.1

88.387.987.4

73.973.072.0

62.060.959.8

613595577

650630612

577560543

313301292

896891887

535251

77.476.876.3

65.464.663.8

86.986.485.9

71.270.269.4

58.657.456.1

560544528

594576558

525512496

283273264

883879874

504948

75.975.274.7

63.162.161.4

85.585.084.5

68.567.666.7

55.053.852.5

513498484

542526510

481469455

255246238

870865861

474645

74.173.673.1

60.860.059.2

83.983.583.0

65.864.864.0

51.450.349.0

471458446

495480466

443432421

229221215

856851847

444342

72.572.071.5

58.557.756.9

82.582.081.5

63.162.261.3

47.846.745.5

434423412

452438426

409400390

208201194

842837832

414039

70.970.469.9

56.255.454.6

80.980.479.9

60.459.558.6

44.343.141.9

402392382

414402391

381371362

188182177

827822817

383736

69.468.968.4

53.853.152.3

79.478.878.3

57.756.855.9

40.839.638.4

372363354

380370360

353344336

171166161

812807802

353433

67.967.466.8

51.550.850.0

77.777.276.6

55.054.253.3

37.236.134.9

345336327

351342334

327319311

156152149

798793788

323130

66.365.865.3

49.248.447.7

NA92.0

76.175.675.0

52.151.350.4

33.732.531.3

318310302

326318311

301294286

146141138

783778773

292827

64.664.363.8

47.046.145.2

91.090.089.0

74.573.973.3

49.548.647.7

30.128.927.8

294286279

304297290

279271264

135131128

768762757

262524

63.362.862.4

44.643.843.1

88.087.086.0

72.872.271.6

46.845.945.0

26.725.524.3

272266260

284278272

258253247

125123119

751746741

232221

62.061.561.0

42.141.640.9

84.583.582.5

71.070.569.9

44.043.242.3

23.122.020.7

254248243

266261256

243237231

117115112

736730725

20 60.5 40.1 81.0 69.4 41.5 19.6 238 251 226 110 720

Hardened Steel and Hardened Alloys

Note 1: A 10 mm steel ball was used for 450 BHN and below. A 10 mm carbide ball was used above 450 BHN.2: The tensile strength relation to hardness is not exact, even for steel, unless it is determined for a specifi c material.

These corrections are approximate only and represent the averages to the nearest 1/2 Rockwell number.

Any greater thickness and

hardness can besafely tested onindicated scale

RockwellSuperfi cial

Hardness Scales

RockwellRegular

Hardness Scales

15N 30N 45N A D C15kgf

30kgf

45kgf

60kgf

100kgf

150kgf

Thicknessinches (mm)

N BraleIndenter

BraleIndenter

.006 (0.15) 92 - - - - -

.008 (0.20) 90 - - - - -

.010 (0.25) 88 - - - - -

.012 (0.30) 83 82 77 - - -

.014 (0.36) 76 78.5 74 - - -

.016 (0.41) 68 74 72 86 - -

.018 (0.46) × 66 68 84 - -

.020 (0.51) × 57 63 82 77 -

.022 (0.56) × 47 58 79 75 69

.024 (0.61) × × 51 76 72 67

.026 (0.66) × × 37 71 68 65

.028 (0.71) × × 20 67 63 62

.030 (0.76) × × × 60 58 57

.032 (0.81) × × × × 51 52

.034 (0.86) × × × × 43 45

.036 (0.91) × × × × × 37

.038 (0.96) × × × × × 28

.040 (1.02) × × × × × 20Any greater

thickness andhardness can besafely tested onindicated scale

RockwellSuperfi cial

Hardness Scales

RockwellRegular

Hardness Scales

15-T 30-T 45-T F B G15kgf

30kgf

45kgf

60kgf

100kgf

150kgf

Thicknessinches (mm)

1/16-in BallIndenter

1/16-in BallIndenter

.010 (0.25) 91 - - - - -

.012 (0.30) 86 - - - - -

.014 (0.36) 81 80 - - - -

.016 (0.41) 75 72 71 - - -

.018 (0.46) 68 64 62 - - -

.020 (0.51) × 55 53 - - -

.022 (0.56) × 45 43 - - -

.024 (0.61) × 34 31 98 94 94

.026 (0.66) × × 18 91 87 87

.028 (0.71) × × 4 85 80 76

.030 (0.76) × × × 77 71 68

.032 (0.81) × × × 69 62 59

.034 (0.86) × × × × 52 50

.036 (0.91) × × × × 40 42

.038 (0.96) × × × × 28 31

.040 (1.02) × × × × × 22

Hardness vs Minimum Thickness Chart 55

X = No minimum hardness. These are approximate numbers only.

The values shown are approximate only. This chart is intended primarily as a reference guide.

Worldwide Service Network | 1-800-473-7838Wilson Instruments is an Instron® ITW company and is backed by Instron’s professional service force. It is the industry’s largest and most responsive group, including factory trained and certifi ed service engineers, application engineers, and service specialists. Instron fi eld personnel expertise is just a phone call away.

Services include:

• Calibration and Certifi cation

• Preventative Maintenance

• Emergency Service

• Installation and Relocation

• On-site Parts and Accessories

• Application Support and Solutions

• On-site Training

Hardness Products Wilson Instruments offers a full range of Wilson testing products and technology to meet virtually any hardness testing application and budget.

• Rockwell Testers

• Knoop and Vickers Testers

• Image Analysis and Automatic Systems

• Brinell Testers

• Universal Hardness Testers

• Shore® Durometers for Rubber and Plastic

• Portable Testers

• Custom Solutions

• Test Blocks, Indenters, and Accessories

NO

TE 2

NO

TE 2

NO

TE 1

1.800.695.4273 | 1.781.575.6000 www.wilson-hardness.com

Originator of the Rockwell® TesterAmericas | Europe | Asia

Conversion Chart

®