HARDNESS
CONVERSION TABLE (Approximate Value)

Brinell

Rockwell

Tensile Strength

Diameter 3000 Kg. Load 10 mm. Ball

Hardness No.

C

B

A

15-N

Shore

Tensile     Strength
1000
Lb./Sq. In.

2.25

745

65.3

—

84.1

92.3

91

—

2.30

712

—

—

—

—

—

—

2.35

682

61.7

—

82.2

91.0

84

—

2.40

653

60.0

—

81.2

90.2

81

—

2.45

627

58.7

—

80.5

89.6

79

—

2.50

601

57.3

—

79.8

89.0

77

—

2.55

578

56.0

—

79.1

88.4

75

—

2.60

555

54.7

—

78.4

87.8

73

298

2.65

534

53.5

—

77.8

87.2

71

288

2.70

514

52.1

—

76.9

86.5

70

274

2.75

495

51.0

—

76.3

85.9

68

264

2.80

477

49.6

—

75.6

85.3

66

252

2.85

461

48.5

—

74.9

84.7

65

242

2.90

444

47.1

—

74.2

84.0

63

230

2.95

429

45.7

—

73.4

83.4

61

219

3.00

415

44.5

—

72.8

82.8

59

212

3.05

401

43.1

—

72.0

82.0

58

202

3.10

388

41.8

—

71.4

81.4

56

193

3.15

375

40.4

—

70.6

80.6

54

184

3.20

363

39.1

—

70.0

80.0

52

177

3.25

352

37.9

(110.0)

69.3

79.3

51

170

3.30

341

36.6

(109.0)

68.7

78.6

50

163

3.35

331

35.5

(108.5)

68.1

78.0

48

158

3.40

321

34.3

(108.0)

67.5

77.3

47

152

3.45

311

33.1

(107.5)

66.9

76.7

46

147

3.50

302

32.1

(107.0)

66.3

76.1

45

143

3.55

293

30.9

(106.0)

65.7

75.5

43

139

3.60

285

29.9

(105.5)

65.3

75.0

—

135

3.65

277

28.8

(104.5)

64.6

74.4

41

131

3.70

269

27.6

(104.0)

64.1

73.7

40

128

3.75

262

26.6

(103.0)

63.6

73.1

39

125

3.80

255

25.4

(102.0)

63.0

72.5

38

121

3.85

248

24.2

(101.0)

62.5

71.7

37

118

3.90

241

22.8

100.0

61.8

70.9

36

114

3.95

235

21.7

99.0

61.4

70.3

35

111

4.00

229

20.5

98.2

60.8

69.7

34

109

4.05

223

(18.8)

97.3

—

—

—

104

4.10

217

(17.5)

96.4

—

—

33

103

4.15

212

(16.0)

95.5

—

—

—

100

4.20

207

(15.2)

94.6

—

—

32

99

4.25

201

(13.8)

93.8

—

—

31

97

4.30

197

(12.7)

92.8

—

—

30

94

4.35

192

(11.5)

91.9

—

—

29

92

4.40

187

(10.0)

90.7

—

—

—

90

4.45

183

(9.0)

90.0

—

—

28

89

4.50

179

(8.0)

89.0

—

—

27

88

4.55

174

(6.4)

87.8

—

—

—

86

4.60

170

(5.4)

86.8

—

—

26

84

4.65

167

(4.4)

86.0

—

—

—

83

4.70

163

(3.3)

85.0

—

—

25

82

4.80

156

(0.9)

82.9

—

—

—

80

4.90

149

—

80.8

—

—

23

—

5.00

143

—

78.7

—

—

22

—

5.10

137

—

76.4

—

—

21

—

5.20

131

—

74.0

—

—

—

—

5.30

126

—

72.0

—

—

20

—

5.40

121

—

69.8

—

—

19

—

5.50

116

—

67.6

—

—

18

—

5.60

111

—

65.7

—

—

15

—

Hardness values are from SAE-ASM-ASTM
Committees on Hardness Conversions as printed in ASTME 140, Table 3.
Tensile Strength values are from Federal Test Methods Standard No.
151A-method 241.2 dated Jan. 10 1961.