Hardness Conversion Tables

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 HARDNESS CONVERSION TABLE (BASED ON BRINELL HARDNESS HB)

Brinell

Brinell

 

Rockwell Hardness

Rockwell Superficial Hardness

Approximate

Indentation

3000 kgf

 

Rockwell A

Rockwell B

Rockwell C

Rockwell D

 

 

 

Tensile

Diameter

10 mm

 

60 kgf

100 kgf

150 kgf

100 kgf

15 kgf

30 kgf

45 kgf

Strength

mm

Ball

Vickers

Diamond

1//16" ball

Diamond

Diamond

1/16" ball

1/16" ball

1/16" ball

ksi (MPa)

 

HB

HV

HRA

HRB

HRC

HRD

HR15N

HR30N

HR45N

 

---

---

940

85.6

---

68.0

76.9

93.2

84.4

75.4

---

---

---

920

85.3

---

67.5

76.5

93.0

84.0

74.8

---

---

---

900

85.0

---

67.0

76.1

92.9

83.6

74.2

---

---

767

880

84.7

---

66.4

75.7

92.7

83.1

73.6

---

---

757

860

84.4

---

65.9

75.3

92.5

82.7

73.1

---

 

 

 

 

 

 

 

 

 

 

 

2.25

745

840

84.1

---

65.3

74.8

92.3

82.2

72.2

---

---

733

820

83.8

---

64.7

74.3

92.1

81.7

71.8

---

---

722

800

83.4

---

64.0

73.8

91.8

81.1

71.0

---

2.30

712

---

---

---

---

---

---

---

---

---

---

710

780

83.0

---

63.3

73.3

91.5

80.4

70.2

---

---

698

760

82.6

---

62.5

72.6

91.2

79.7

69.4

---

 

 

 

 

 

 

 

 

 

 

 

---

684

740

82.2

---

61.8

72.1

91.0

79.1

68.

---

2.35

682

737

82.2

---

61.7

72.0

91.0

79.0

68.5

---

---

670

720

81.8

---

61.0

71.5

90.7

78.4

67.7

---

---

656

700

81.3

---

60.1

70.8

90.3

77.6

66.7

---

2.40

653

697

81.2

---

60.0

70.7

90.2

77.5

66.5

---

 

 

 

 

 

 

 

 

 

 

 

---

647

690

81.1

---

59.7

70.5

90.1

77.2

66.2

---

---

638

680

80.8

---

59.2

70.1

89.8

76.8

65.7

---

---

630

670

80.6

---

58.8

69.8

89.7

76.4

65.3

---

2.45

627

667

80.5

---

58.7

69.7

89.6

76.3

65.1

---

 

 

 

 

 

 

 

 

 

 

 

2.50

---

601

677

640

80.7

79.8

---

---

59.1

57.3

70.0

68.7

89.8

89.0

76.8

75.1

65.7

63.5

---

---

Brinell

Brinell

 

Rockwell Hardness

Rockwell Superficial Hardness

Approximate

Indentation

3000 kgf

 

Rockwell A

Rockwell B

Rockwell C

Rockwell D

 

 

 

Tensile

Diameter

10 mm

 

60 kgf

100 kgf

150 kgf

100 kgf

15 kgf

30 kgf

45 kgf

Strength

mm

Ball

Vickers

Diamond

1//16" ball

Diamond

Diamond

1/16" ball

1/16" ball

1/16" ball

ksi (MPa)

 

HB

HV

HRA

HRB

HRC

HRD

HR15N

HR30N

HR45N

 

 

 

 

 

 

 

 

 

 

 

 

2.55

---

578

640

615

79.8

79.1

---

---

57.3

56.0

68.7

67.7

89.0

88.4

75.1

73.9

63.5

62.1

---

---

 

 

 

 

 

 

 

 

 

 

 

2.60

---

555

607

591

78.8

78.4

---

---

55.6

54.7

67.4

66.7

88.1

87.8

73.5

72.7

61.6

60.6

---

2055

 

 

 

 

 

 

 

 

 

 

 

2.65

---

534

579

569

78.0

77.8

---

---

54.0

53.5

66.1

65.8

87.5

87.2

72.0

71.6

59.8

59.2

2015

1985

 

 

 

 

 

 

 

 

 

 

 

2.70

---

514

553

547

77.1

76.9

---

---

52.5

52.1

65.0

64.7

86.7

86.5

70.7

70.3

58.0

57.6

1915

1890

 

 

 

 

 

 

 

 

 

 

 

2.75

---

---

495

539

530

528

76.7

76.4

76.3

---

---

---

51.6

51.1

51.0

64.3

63.9

63.8

86.3

86.0

85.9

69.9

69.5

69.4

56.9

56.2

56.1

1855

1825

1820

 

 

 

 

 

 

 

 

 

 

 

2.80

---

477

516

508

75.9

75.6

---

---

50.3

49.6

63.2

62.7

85.6

85.3

68.7

68.2

55.2

54.5

1780

1740

 

 

 

 

 

 

 

 

 

 

 

2.85

---

461

495

491

75.1

74.9

---

---

48.8

48.5

61.9

61.7

84.9

84.7

67.4

67.2

53.5

53.2

1680

1670

 

 

 

 

 

 

 

 

 

 

 

2.90

---

444

474

472

74.3

74.2

---

---

47.2

47.1

61.0

60.8

84.1

84.0

66.0

65.8

51.7

51.5

1595

1585

Brinell

Brinell

 

Rockwell Hardness

Rockwell Superficial Hardness

Approximate

Indentation

3000 kgf

 

Rockwell A

Rockwell B

Rockwell C

Rockwell D

 

 

 

Tensile

Diameter

10 mm

 

60 kgf

100 kgf

150 kgf

100 kgf

15 kgf

30 kgf

45 kgf

Strength

mm

Ball

Vickers

Diamond

1//16" ball

Diamond

Diamond

1/16" ball

1/16" ball

1/16" ball

ksi (MPa)

 

HB

HV

HRA

HRB

HRC

HRD

HR15N

HR30N

HR45N

 

 

 

 

 

 

 

 

 

 

 

 

2.95

429

455

73.4

---

45.7

59.7

83.4

64.6

49.9

1510

3.00

415

440

72.8

---

44.5

58.8

82.8

63.5

48.4

1460

3.05

401

425

72.0

---

43.1

57.8

82.0

62.3

46.9

1390

 

 

 

 

 

 

 

 

 

 

 

3.10

388

410

71.4

---

41.8

56.8

81.4

61.1

45.3

1330

3.15

375

396

70.6

---

40.4

55.7

80.6

59.9

43.6

1270

3.20

363

383

70.0

---

39.1

54.6

80.0

58.7

42.0

1220

3.25

352

372

69.3

(110.0)

37.9

53.8

79.3

57.6

40.5

1180

3.30

341

360

68.7

(109.0)

36.6

52.8

78.6

56.4

39.1

1130

 

 

 

 

 

 

 

 

 

 

 

3.35

331

350

68.1

(108.5)

35.5

51.9

78.0

55.4

37.8

1095

3.40

321

339

67.5

(108.0)

34.3

51.0

77.3

54.3

36.4

1060

3.45

311

328

66.9

(107.5)

33.1

50.0

76.7

53.3

34.4

1025

3.50

302

319

66.3

(107.0)

32.1

49.3

76.1

52.2

33.8

1005

3.55

293

309

65.7

(106.0)

30.9

48.3

75.5

51.2

32.4

970

 

 

 

 

 

 

 

 

 

 

 

3.60

285

301

65.3

(105.5)

29.9

47.6

75.0

50.3

31.2

950

3.65

277

292

64.6

(104.5)

28.8

46.7

74.4

49.3

29.9

925

3.70

269

284

64.1

(104.0)

27.6

45.9

73.7

48.3

28.5

895

3.75

262

276

63.6

(103.0)

26.6

45.0

73.1

47.3

27.3

875

3.80

255

269

63.0

(102.0)

25.4

44.2

72.5

46.2

26.0

850

Brinell

Brinell

 

Rockwell Hardness

Rockwell Superficial Hardness

Approximate

Indentation

3000 kgf

 

Rockwell A

Rockwell B

Rockwell C

Rockwell D

 

 

 

Tensile

Diameter

10 mm

 

60 kgf

100 kgf

150 kgf

100 kgf

15 kgf

30 kgf

45 kgf

Strength

mm

Ball

Vickers

Diamond

1//16" ball

Diamond

Diamond

1/16" ball

1/16" ball

1/16" ball

ksi (MPa)

 

HB

HV

HRA

HRB

HRC

HRD

HR15N

HR30N

HR45N

 

3.85

248

261

62.5

(101.0)

24.2

43.2

71.7

45.1

24.5

825

3.90

241

253

61.8

100.0

22.8

42.0

70.9

43.9

22.8

800

3.95

235

247

61.4

99.0

21.7

41.4

70.3

42.9

21.5

785

4.00

229

241

60.8

98.2

20.5

40.5

69.7

41.9

20.1

765

4.05

223

234

 

97.3

(18.8)

---

---

---

---

---

 

 

 

 

 

 

 

 

 

 

 

4.10

217

228

---

96.4

(17.5)

---

---

---

---

725

4.15

212

222

---

95.5

(16.0)

---

---

---

---

705

4.20

207

218

---

94.6

(15.2)

---

---

---

---

690

4.25

201

212

---

93.8

(13.8)

---

---

---

---

675

4.30

197

207

---

92.8

(12.7)

---

---

---

---

655

 

 

 

 

 

 

 

 

 

 

 

4.35

192

202

---

91.9

(11.5)

---

---

---

---

640

4.40

187

196

---

90.7

(10.0)

---

---

---

---

620

4.45

183

192

---

90.0

(9.0)

---

---

---

---

615

4.50

179

188

---

89.0

(8.0)

---

---

---

---

600

4.55

174

182

---

87.8

(6.4)

---

---

---

---

585

 

 

 

 

 

 

 

 

 

 

 

4.60

170

178

---

86.8

(5.4)

---

---

---

---

570

4.65

167

175

---

86.0

(4.4)

---

---

---

---

560

4.70

163

171

---

85.0

(3.3)

---

---

---

---

545

4.80

156

163

---

82.9

(0.9)

---

---

---

---

525

4.90

149

156

---

80.8

---

---

---

---

---

505

Brinell

Brinell

 

Rockwell Hardness

Rockwell Superficial Hardness

Approximate

Indentation

3000 kgf

 

Rockwell A

Rockwell B

Rockwell C

Rockwell D

 

 

 

Tensile

Diameter

10 mm

 

60 kgf

100 kgf

150 kgf

100 kgf

15 kgf

30 kgf

45 kgf

Strength

mm

Ball

Vickers

Diamond

1//16" ball

Diamond

Diamond

1/16" ball

1/16" ball

1/16" ball

ksi (MPa)

 

HB

HV

HRA

HRB

HRC

HRD

HR15N

HR30N

HR45N

 

5.00

143

150

---

78.7

---

---

---

---

---

490

5.10

137

143

---

76.4

---

---

---

---

---

460

5.20

131

137

---

74.0

---

---

---

---

---

450

5.30

126

132

---

72.0

---

---

---

---

---

435

5.40

121

127

---

69.8

---

---

---

---

---

415

 

 

 

 

 

 

 

 

 

 

 

5.50

116

122

---

67.6

---

---

---

---

---

400

5.60

111

117

---

65.7

---

---

---

---

---

385

 

 

 

 

 

 

 

 

 

 

 

 

 

HARDNESS CONVERSION TABLE (BASED ON HRC)

 

 

Brinell

Rockwell Hardness

Rockwell Superficial Hardness

 

 

Rockwell C

 

3000 kgf

Rockwell A

Rockwell B

Rockwell D

 

 

 

Approximate

Rockwell C

150 kgf

Vickers

10 mm

60 kgf

100 kgf

100 kgf

15 kgf

30 kgf

45 kgf

Tensile

150 kgf

Diamond

Hardness

Ball

Diamond

1//16" ball

Diamond

1/16" ball

1/16" ball

1/16" ball

Strength

Diamond

HRC

HV

HB

HRA

HRB

HRD

HR15N

HR30N

HR45N

ksi (MPa)

HRC

68

940

---

85.6

---

76.9

93.2

84.4

75.4

---

68

67

900

---

85.0

---

76.1

92.9

83.6

74.2

---

67

66

865

---

84.5

---

75.4

92.5

82.8

73.3

---

66

65

832

739

83.9

---

74.5

92.2

81.9

72.0

---

65

64

800

722

83.4

---

73.8

91.8

81.1

71.0

---

64

 

 

 

 

 

 

 

 

 

 

 

63

772

705

82.8

---

73.0

91.4

80.1

69.9

---

63

62

746

688

82.3

---

72.2

91.1

79.3

68.8

---

62

61

720

670

81.8

---

71.5

90.7

78.4

67.7

---

61

60

697

654

81.2

---

70.7

90.2

77.5

66.6

---

60

59

674

634

80.7

---

69.9

89.8

76.6

65.5

---

59

 

 

 

 

 

 

 

 

 

 

 

58

653

615

80.1

---

69.2

89.3

75.7

64.3

---

58

57

633

595

79.6

---

68.5

88.9

74.8

63.2

---

57

56

613

577

79.0

---

67.7

88.3

73.9

62.0

---

56

55

595

560

78.5

---

66.9

87.9

73.0

60.9

2075

55

54

577

543

78.0

---

66.1

87.4

72.0

59.8

2015

54

 

 

 

 

 

 

 

 

 

 

 

53

560

525

77.4

---

65.4

86.9

71.2

58.6

1950

53

52

544

512

76.8

---

64.6

86.4

70.2

57.4

1880

52

51

528

496

76.3

---

63.8

85.9

69.4

56.1

1820

51

50

513

481

75.9

---

63.1

85.5

68.5

55.0

1760

50

49

498

469

75.2

---

62.1

85.0

67.6

53.8

1695

49

 

 

Brinell

Rockwell Hardness

Rockwell Superficial Hardness

 

 

Rockwell C

 

3000 kgf

Rockwell A

Rockwell B

Rockwell D

 

 

 

Approximate

Rockwell C

150 kgf

Vickers

10 mm

60 kgf

100 kgf

100 kgf

15 kgf

30 kgf

45 kgf

Tensile

150 kgf

Diamond

Hardness

Ball

Diamond

1//16" ball

Diamond

1/16" ball

1/16" ball

1/16" ball

Strength

Diamond

HRC

HV

HB

HRA

HRB

HRD

HR15N

HR30N

HR45N

ksi (MPa)

HRC

48

484

455

74.7

---

61.4

84.5

66.7

52.5

1635

48

47

471

443

74.1

---

60.8

83.9

65.8

51.4

1580

47

46

458

432

73.6

---

60.0

83.5

64.8

50.3

1530

46

45

446

421

73.1

---

59.2

83.0

64.0

49.0

1480

45

44

434

409

72.5

---

58.5

82.5

63.1

47.8

1435

44

 

 

 

 

 

 

 

 

 

 

 

43

423

400

72.0

---

57.7

82.0

62.2

46.7

1385

43

42

412

390

71.5

---

56.9

81.5

61.3

45.5

1340

42

41

402

381

70.9

---

56.2

80.9

60.4

44.3

1295

41

40

392

371

70.4

---

55.4

80.4

59.5

43.1

1250

40

39

382

362

69.9

---

54.6

79.9

58.6

41.9

1215

39

 

 

 

 

 

 

 

 

 

 

 

38

372

353

69.4

---

53.8

79.4

57.7

40.8

1180

38

37

363

344

68.9

---

53.1

78.8

56.8

39.6

1160

37

36

354

336

68.4

(109.0)

52.3

78.3

55.9

38.4

1115

36

35

345

327

67.9

(108.5)

51,5

77.7

55.0

37.2

1080

35

34

336

319

67.4

(108.0)

50.8

77.2

54.2

36.1

1055

34

 

 

 

 

 

 

 

 

 

 

 

33

327

311

66.8

(107.5)

50.0

76.6

53.3

34.9

1025

33

32

318

301

66.3

(107.0)

49.2

76.1

52.1

33.7

1000

32

31

310

294

65.8

(106.0)

48.4

75.6

51.3

32.5

980

31

30

302

286

65.3

(105.5)

47.7

75.0

50.4

31.3

950

30

29

294

279

64.7

(104.5)

47.0

74.5

49.5

30.1

930

29

 

 

Brinell

Rockwell Hardness

Rockwell Superficial Hardness

 

 

Rockwell C

286

3000 kgf

Rockwell A

Rockwell B

Rockwell D

 

 

 

Approximate

Rockwell C

150 kgf

Vicke279rs

10 mm

60 kgf

100 kgf

100 kgf

15 kgf

30 kgf

45 kgf

Tensile

150 kgf

Diamond

Hardnes272s

Ball

Diamond

1//16" ball

Diamond

1/16" ball

1/16" ball

1/16" ball

Strength

Diamond

HRC

HV

HB

HRA

HRB

HRD

HR15N

HR30N

HR45N

ksi (MPa)

HRC

28

286

271

64.3

(104.0)

46.1

73.9

48.6

28.9

910

28

27

279

264

63.8

(103.0)

45.2

73.3

47.7

27.8

880

27

26

272

258

63.3

(102.5)

44.6

72.8

46.8

26.7

860

26

25

266

253

62.8

(101.5)

43.8

72.2

45.9

25.5

840

25

24

260

247

62.4

(101.0)

43.1

71.6

45.0

24.3

825

24

 

 

 

 

 

 

 

 

 

 

 

23

254

243

62.0

100.0

42.1

71.0

44.0

23.1

805

23

22

248

237

61.5

99.0

41.6

70.5

43.2

22.0

785

22

21

243

231

61.0

98.5

40.9

69.9

42.3

20.7

770

21

20

238

226

60.5

97.8

40.1

69.4

41.5

19.6

760

20

(18)

230

219

---

96.7

---

---

---

---

730

(18)

 

 

 

 

 

 

 

 

 

 

 

(16)

222

212

---

95.5

---

---

---

---

705

(16)

(14)

213

203

---

93.9

---

---

---

---

675

(14)

(12)

204

194

---

92.3

---

---

---

---

650

(12)

(10)

196

187

---

90.7

---

---

---

---

620

(10)

(8)

188

179

---

89.5

---

---

---

---

600

(8)

 

 

 

 

 

 

 

 

---

 

 

(6)

180

171

---

87.1

---

---

---

---

580

(6)

(4)

173

165

---

85.5

---

---

---

---

550

(4)

(2)

166

158

---

83.5

---

---

---

---

530

(2)

(0)

160

152

---

81.7

---

---

---

---

510

(0)

 

ASTM E 140 Hardness Conversion Tables for Metals

ASTM E140 Standard Hardness Conversion Tables for Metals-Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Knoop Hardness, Superficial Hardness, and Scleroscope Hardness

 

Approximate Hardness Conversion Numbers for Non-Austenitic Steels (Rockwell C Hardness Range) A, B

 

Rockwell C
Hardness
Number
150 kgf
(HRC)

Vickers
Hardness
Number
(HV)

Brinell Hardness 
Number C

Knoop
Hardness,
Number
500-gf and
Over (HK)

Rockwell Hardness Number

Rockwell Superficial 
Hardness Number

Scleroscope
Hardness
Number D

Rockwell C
Hardness
Number
150 kgf
(HRC)
10-mm
Standard Ball,
3000-kgf
(HBS)		 10-mm
Carbide Ball,
3000-kgf
(HBW)		 A Scale,
60-kgf (HRA)		 D Scale,
100-kgf (HRD)		 15-N Scale,
15-kgf
(HR 15-N)		 30-N Scale,
30-kgf
(HR 30-N)		 45-N Scale,
45-kgf
(HR 45-N)
68 940 --- --- 920 85.6 76.9 93.2 84.4 75.4 97.3 68
67 900 --- --- 895 85.0 76.1 92.9 83.6 74.2 95.0 67
66 865 --- --- 870 84.5 75.4 92.5 82.8 73.3 92.7 66
65 832 --- (739) 846 83.9 74.5 92.2 81.9 72.0 90.6 65
64 800 --- (722) 822 83.4 73.8 91.8 81.1 71.0 88.5 64
63 772 --- (705) 799 82.8 73.0 91.4 80.1 69.9 86.5 63
62 746 --- (688) 776 82.3 72.2 91.1 79.3 68.8 84.5 62
61 720 --- (670) 754 81.8 71.5 90.7 78.4 67.7 82.6 61
60 697 --- (654) 732 81.2 70.7 90.2 77.5 66.6 80.8 60
59 674 --- 634 710 80.7 69.9 89.8 76.6 65.5 79.0 59
58 653 --- 615 690 80.1 69.2 89.3 75.7 64.3 77.3 58
57 633 --- 595 670 79.6 68.5 88.9 74.8 63.2 75.6 57
56 613 --- 577 650 79.0 67.7 88.3 73.9 62.0 74.0 56
55 595 --- 560 630 78.5 66.9 87.9 73.0 60.9 72.4 55
54 577 --- 543 612 78.0 66.1 87.4 72.0 59.8 70.9 54
53 560 --- 525 594 77.4 65.4 86.9 71.2 58.6 69.4 53
52 544 (500) 512 576 76.8 64.6 86.4 70.2 57.4 67.9 52
51 528 (487) 496 558 76.3 63.8 85.9 69.4 56.1 66.5 51
50 513 (475) 481 542 75.9 63.1 85.5 68.5 55.0 65.1 50
49 498 (464) 469 526 75.2 62.1 85.0 67.6 53.8 63.7 49
48 484 451 455 510 74.7 61.4 84.5 66.7 52.5 62.4 48
47 471 442 443 495 74.1 60.8 83.9 65.8 51.4 61.1 47
46 458 432 432 480 73.6 60.0 83.5 64.8 50.3 59.8 46
Rockwell C
Hardness
Number
150 kgf
(HRC)		 Vickers
Hardness
Number
(HV)		 Brinell Hardness 
Number C		 Knoop
Hardness,
Number
500-gf and
Over (HK)		 Rockwell Hardness Number Rockwell Superficial 
Hardness Number		 Scleroscope
Hardness
Number D		 Rockwell C
Hardness
Number
150 kgf
(HRC)
10-mm
Standard Ball,
3000-kgf
(HBS)		 10-mm
Carbide Ball,
3000-kgf
(HBW)		 A Scale,
60-kgf (HRA)		 D Scale,
100-kgf (HRD)		 15-N Scale,
15-kgf
(HR 15-N)		 30-N Scale,
30-kgf
(HR 30-N)		 45-N Scale,
45-kgf
(HR 45-N)
45 446 421 421 466 73.1 59.2 83.0 64.0 49.0 58.5 45
44 434 409 409 452 72.5 58.5 82.5 63.1 47.8 57.3 44
43 423 400 400 438 72.0 57.7 82.0 62.2 46.7 56.1 43
42 412 390 390 426 71.5 56.9 81.5 61.3 45.5 54.9 42
41 402 381 381 414 70.9 56.2 80.9 60.4 44.3 53.7 41
40 392 371 371 402 70.4 55.4 80.4 59.5 43.1 52.6 40
39 382 362 362 391 69.9 54.6 79.9 58.6 41.9 51.5 39
38 372 353 353 380 69.4 53.8 79.4 57.7 40.8 50.4 38
37 363 344 344 370 68.9 53.1 78.8 56.8 39.6 49.3 37
36 354 336 336 360 68.4 52.3 78.3 55.9 38.4 48.2 36
35 345 327 327 351 67.9 51.5 77.7 55.0 37.2 47.1 35
34 336 319 319 342 67.4 50.8 77.2 54.2 36.1 46.1 34
33 327 311 311 334 66.8 50.0 76.6 53.3 34.9 45.1 33
32 318 301 301 326 66.3 49.2 76.1 52.1 33.7 44.1 32
31 310 294 294 318 65.8 48.4 75.6 51.3 32.5 43.1 31
30 302 286 286 311 65.3 47.7 75.0 50.4 31.3 42.2 30
29 294 279 279 304 64.8 47.0 74.5 49.5 30.1 41.3 29
28 286 271 271 297 64.3 46.1 73.9 48.6 28.9 40.4 28
27 279 264 264 290 63.8 45.2 73.3 47.7 27.8 39.5 27
26 272 258 258 284 63.3 44.6 72.8 46.8 26.7 38.7 26
25 266 253 253 278 62.8 43.8 72.2 45.9 25.5 37.8 25
24 260 247 247 272 62.4 43.1 71.6 45.0 24.3 37.0 24
23 254 243 243 266 62.0 42.1 71.0 44.0 23.1 36.3 23
22 248 237 237 261 61.5 41.6 70.5 43.2 22.0 35.5 22
21 243 231 231 256 61.0 40.9 69.9 42.3 20.7 34.8 21
20 238 226 226 251 60.5 40.1 69.4 41.5 19.6 34.2 20

A In the table headings, force refers to total test forces.
B Appendix X1 contains equations converting determined hardness scale numbers to Rockwell C hardness numbers for non-austenitic steels.
C The Brinell hardness numbers in parentheses are outside the range recommended for Brinell hardness testing in 8.1 of Test Method E 10.
D These Scleroscope hardness conversions are based on Vickers—Scleroscope hardness relationships developed from Vickers hardness data provided by the National Bureau of Standards for 13 steel reference blocks, Scleroscope hardness values obtained on these blocks by the Shore Instrument and Mfg. Co., Inc., the Roll Manufacturers Institute, and members of this institute, and also on hardness conversions previously published by the American Society for Metals and the Roll Manufacturers Institute.

Approximate Hardness Conversion Numbers for Non-Austenitic Steels (Rockwell B Hardness Range) A, B

Rockwell B
Hardness
Number,
100-kgf
(HRB)		 Vickers
Hardness
Number
(HV)		 Brinell Hardness
Number,
3000-kgf,
(HBS)		 Knoop Hardness
Number,
500-gf, and
Over
(HK)		 Rockwell A
Hardness
Number,
60-kgf,
(HRA)		 Rockwell F
Hardness
Number,
60-kgf,
(HRF)		 Rockwell Superficial Hardness Number Rockwell B
Hardness
Number,
100-kgf,
(HRB)
15-T Scale,
15-kgf,
(HR 15-T)		 30-T Scale,
30-kgf,
(HR 30-T)		 45-T Scale,
45-kgf,
(HR 45-T)
100 240 240 251 61.5 --- 93.1 83.1 72.9 100
99 234 234 246 60.9 --- 92.8 82.5 71.9 99
98 228 228 241 60.2 --- 92.5 81.8 70.9 98
97 222 222 236 59.5 --- 92.1 81.1 69.9 97
96 216 216 231 58.9 --- 91.8 80.4 68.9 96
95 210 210 226 58.3 --- 91.5 79.8 67.9 95
94 205 205 221 57.6 --- 91.2 79.1 66.9 94
93 200 200 216 57.0 --- 90.8 78.4 65.9 93
92 195 195 211 56.4 --- 90.5 77.8 64.8 92
91 190 190 206 55.8 --- 90.2 77.1 63.8 91
90 185 185 201 55.2 --- 89.9 76.4 62.8 90
89 180 180 196 54.6 --- 89.5 75.8 61.8 89
88 176 176 192 54.0 --- 89.2 75.1 60.8 88
87 172 172 188 53.4 --- 88.9 74.4 59.8 87
86 169 169 184 52.8 --- 88.6 73.8 58.8 86
85 165 165 180 52.3 --- 88.2 73.1 57.8 85
84 162 162 176 51.7 --- 87.9 72.4 56.8 84
83 159 159 173 51.1 --- 87.6 71.8 55.8 83
82 156 156 170 50.6 --- 87.3 71.1 54.8 82
81 153 153 167 50.0 --- 86.9 70.4 53.8 81
80 150 150 164 49.5 --- 86.6 69.7 52.8 80
79 147 147 161 48.9 --- 86.3 69.1 51.8 79
Rockwell B
Hardness
Number,
100-kgf
(HRB)		 Vickers
Hardness
Number
(HV)		 Brinell Hardness
Number,
3000-kgf,
(HBS)		 Knoop Hardness
Number,
500-gf, and
Over
(HK)		 Rockwell A
Hardness
Number,
60-kgf,
(HRA)		 Rockwell F
Hardness
Number,
60-kgf,
(HRF)		 Rockwell Superficial Hardness Number Rockwell B
Hardness
Number,
100-kgf,
(HRB)
15-T Scale,
15-kgf,
(HR 15-T)		 30-T Scale,
30-kgf,
(HR 30-T)		 45-T Scale,
45-kgf,
(HR 45-T)
78 144 144 158 48.4 --- 86.0 68.4 50.8 78
77 141 141 155 47.9 --- 85.6 67.7 49.8 77
76 139 139 152 47.3 --- 85.3 67.1 48.8 76
75 137 137 150 46.8 99.6 85.0 66.4 47.8 75
74 135 135 147 46.3 99.1 84.7 65.7 46.8 74
73 132 132 145 45.8 98.5 84.3 65.1 45.8 73
72 130 130 143 45.3 98.0 84.0 64.4 44.8 72
71 127 127 141 44.8 97.4 83.7 63.7 43.8 71
70 125 125 139 44.3 96.8 83.4 63.1 42.8 70
69 123 123 137 43.8 96.2 83.0 62.4 41.8 69
68 121 121 135 43.3 95.6 82.7 61.7 40.8 68
67 119 119 133 42.8 95.1 82.4 61.0 39.8 67
66 117 117 131 42.3 94.5 82.1 60.4 38.7 66
65 116 116 129 41.8 93.9 81.8 59.7 37.7 65
64 114 114 127 41.4 93.4 81.4 59.0 36.7 64
63 112 112 125 40.9 92.8 81.1 58.4 35.7 63
62 110 110 124 40.4 92.2 80.8 57.7 34.7 62
61 108 108 122 40.0 91.7 80.5 57.0 33.7 61
60 107 107 120 39.5 91.1 80.1 56.4 32.7 60
59 106 106 118 39.0 90.5 79.8 55.7 31.7 59
58 104 104 117 38.6 90.0 79.5 55.0 30.7 58
57 103 103 115 38.1 89.4 79.2 54.4 29.7 57
56 101 101 114 37.7 88.8 78.8 53.7 28.7 56
55 100 100 112 37.2 88.2 78.5 53.0 27.7 55
54 --- --- 111 36.8 87.7 78.2 52.4 26.7 54
Rockwell B
Hardness
Number,
100-kgf
(HRB)		 Vickers
Hardness
Number
(HV)		 Brinell Hardness
Number,
3000-kgf,
(HBS)		 Knoop Hardness
Number,
500-gf, and
Over
(HK)		 Rockwell A
Hardness
Number,
60-kgf,
(HRA)		 Rockwell F
Hardness
Number,
60-kgf,
(HRF)		 Rockwell Superficial Hardness Number Rockwell B
Hardness
Number,
100-kgf,
(HRB)
15-T Scale,
15-kgf,
(HR 15-T)		 30-T Scale,
30-kgf,
(HR 30-T)		 45-T Scale,
45-kgf,
(HR 45-T)
53 --- --- 110 36.3 87.1 77.9 51.7 25.7 53
52 --- --- 109 35.9 86.5 77.5 51.0 24.7 52
51 --- --- 108 35.5 86.0 77.2 50.3 23.7 51
50 --- --- 107 35.0 85.4 76.9 49.7 22.7 50
49 --- --- 106 34.6 84.8 76.6 49.0 21.7 49
48 --- --- 105 34.1 84.3 76.2 48.3 20.7 48
47 --- --- 104 33.7 83.7 75.9 47.7 19.7 47
46 --- --- 103 33.3 83.1 75.6 47.0 18.7 46
45 --- --- 102 32.9 82.6 75.3 46.3 17.7 45
44 --- --- 101 32.4 82.0 74.9 45.7 16.7 44
43 --- --- 100 32.0 81.4 74.6 45.0 15.7 43
42 --- --- 99 31.6 80.8 74.3 44.3 14.7 42
41 --- --- 98 31.2 80.3 74.0 43.7 13.6 41
40 --- --- 97 30.7 79.7 73.6 43.0 12.6 40
39 --- --- 96 30.3 79.1 73.3 42.3 11.6 39
38 --- --- 95 29.9 78.6 73.0 41.6 10.6 38
37 --- --- 94 29.5 78.0 72.7 41.0 9.6 37
36 --- --- 93 29.1 77.4 72.3 40.3 8.6 36
35 --- --- 92 28.7 76.9 72.0 39.6 7.6 35
34 --- --- 91 28.2 76.3 71.7 39.0 6.6 34
33 --- --- 90 27.8 75.7 71.4 38.3 5.6 33
32 --- --- 89 27.4 75.2 71.0 37.6 4.6 32
31 --- --- 88 27.0 74.6 70.7 37.0 3.6 31
30 --- --- 87 26.6 74.0 70.4 36.3 2.6 30

A In table headings, kgf refers to total test force.
B Appendix X2 contains equations converting determined hardness numbers to Rockwell B hardness numbers for non-austenitic steels. Refer to 1.11 before using conversion equations.

 

Approximate Hardness Conversion Numbers for 
Non-Austenitic Steels (Rockwell C Hardness Range)

 

Rockwell Hardness Number,
B Scale (100-kgf, 1⁄16-in.
(1.588-mm) ball) (HRB)		 Brinell Hardness Number
(3000-kgf, 10-mm ball)
(HBS)
100 256
99 248
98 240
97 233
96 226
95 219
94 213
93 207
92 202
91 197
90 192
89 187
88 183
87 178
86 174
85 170
84 167
83 163
82 160
81 156
80 153
79 150
78 147
77 144
76 142
75 139
74 137
73 135
72 132
71 130
70 128
69 126
68 124
67 122
66 120
65 118
64 116
63 114
62 113
61 111
60 110

Approximate Rockwell Hardness Conversion Numbers for Austenitic Stainless Steel Sheet A,B

Rockwell Hardness Number Rockwell Superficial Hardness Number
C Scale, 150-kgf
Diamond
Penetrator
(HRC)		 A Scale, 60-kgf,
Diamond Penetrator
(HRA)		 15-N Scale, 15-kgf,
Superficial
Diamond Penetrator
(HR 15-N)		 30-N Scale, 30-kgf,
Superficial
Diamond Penetrator
(HR 30-N)		 45-N Scale, 45-kgf,
Superficial
Diamond Penetrator
(HR 45-N)
48 74.4 84.1 66.2 52.1
47 73.9 83.6 65.3 50.9
46 73.4 83.1 64.5 49.8
45 72.9 82.6 63.6 48.7
44 72.4 82.1 62.7 47.5
43 71.9 81.6 61.8 46.4
42 71.4 81.0 61.0 45.2
41 70.9 80.5 60.1 44.1
40 70.4 80.0 59.2 43.0
39 69.9 79.5 58.4 41.8
38 69.3 79.0 57.5 40.7
37 68.8 78.5 56.6 39.6
36 68.3 78 55.7 38.4
35 67.8 77.5 54.9 37.3
34 67.3 77.0 54.0 36.1
33 66.8 76.5 53.1 35.0
32 66.3 75.9 52.3 33.9
31 65.8 75.4 51.4 32.7
30 65.3 74.9 50.5 31.6
29 64.8 74.4 49.6 30.4
28 64.3 73.9 48.8 29.3
27 63.8 73.4 47.9 28.2
26 63.3 72.9 47.0 27.0
25 62.8 72.4 46.2 25.9
24 62.3 71.9 45.3 24.8
23 61.8 71.3 44.4 23.6
22 61.3 70.8 43.5 22.5
21 60.8 70.3 42.7 21.3
20 60.3 69.8 41.8 20.2
         
B Scale, 100-kgf, 1/16-in. (1.588-mm) Ball (HRB) A Scale, 60-kgf, Diamond Penetrator (HRA) F Scale, 60-kgf, 1/16-in. (1.588-mm) Ball C (HRF) 15-T Scale, 15-kgf, 1/16-in. (1.588-mm) Ball (HR 15-T) 30-T Scale, 30-kgf, 1/16-in. (1.588-mm) Ball (HR 30-T) 45-T Scale, 45-kgf, 1/16-in. (1.588-mm) Ball (HR 45-T)
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60

Standard deviation C
61.5
60.9
60.3
59.7
59.1
58.5
58.0
57.4
56.8
56.2
55.6
55.0
54.5
53.9
53.3
52.7
52.1
51.5
50.9
50.4
49.8
49.2
48.6
48.0
47.4
46.9
46.3
45.7
45.1
44.5
43.9
43.3
42.8
42.2
41.6
41.0
40.4
39.8
39.3
38.7
38.1
1.44
(113.9)
(113.2)
(112.5)
(111.8)
(111.1)
(110.5)
(109.8)
(109.1)
(108.4)
(107.8)
(107.1)
(106.4)
(105.7)
(105.0)
(104.4)
(103.7)
(103.0)
(102.3)
(101.7)
(101.0)
(100.3)
99.6
99.0
98.3
97.6
96.9
96.2
95.6
94.9
94.2
93.5
92.8
92.2
91.5
90.8
90.1
89.5
88.8
88.1
87.4
86.8
2.75
91.5
91.2
90.8
90.4
90.1
89.7
89.3
88.9
88.6
88.2
87.8
87.5
87.1
86.7
86.4
86.0
85.6
85.2
84.9
84.5
84.1
83.8
83.4
83.0
82.6
82.3
81.9
81.5
81.2
80.8
80.4
80.1
79.7
79.3
78.9
78.6
78.2
77.8
77.5
77.1
76.7
2.29
80.4
79.7
79.0
78.3
77.7
77.0
76.3
75.6
74.9
74.2
73.5
72.8
72.1
71.4
70.7
70.0
69.3
68.6
67.9
67.2
66.5
65.8
65.1
64.4
63.7
63.0
62.4
61.7
61.0
60.3
59.6
58.9
58.2
57.5
56.8
56.1
55.4
54.7
54.0
53.3
52.6
1.67
70.2
69.2
68.2
67.2
66.1
65.1
64.1
63.1
62.1
61.1
60.1
59.0
58.0
57.0
56.0
55.0
54.0
52.9
51.9
50.9
49.9
48.9
47.9
46.8
45.8
44.8
43.8
42.8
41.8
40.7
39.7
38.7
37.7
36.7
35.7
34.7
33.6
32.6
31.6
30.6
29.6
1.57

A In table headings, kgf or gf refers to total test force.
B Appendix X6 contains equations converting determined hardness numbers to Rockwell C and Rockwell B hardness numbers for austenitic stainless steel sheet. Refer to 1.11 before using conversion equations.
C Observed standard deviation of the inter-laboratory test data about the indicated conversion line.

   
ASTM A 370 Mechanical Testing of Steel Products  
Conversion Tables for Hardness Scales-Cast Rolls  
Hardness Scales Conversion Table - Forged Rolls  
Steel Hardness Conversion Table  
 

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