Common Hardness Scales

  • Brinell Hardness - Used for determining the hardness of metals.This hardness scale is often used for steel parts and comparative conversions between Brinell and Rockwell scales. The comparative scales are listed in the chart below.
  • Rockwell Hardness - Probably the most familiar hardness measurement technique because of its' wide range. Useful for measuring many materials from soft bearing metals to carbides. The different Rockwell scales are listed in the chart below.
  • Shore's Hardness - a common scale for elastic materials such as rubber and plastics.
  • Vicker's Hardness - useful for thin materials.
  • Knoop Hardness - a test applicable to thin materials, plated surfaces , exceptionally hard and brittle materials and shallow hardened surfaces such as surfaces nitrided or carburized.


Hardness Conversion Chart
Brinell Hardness
Rockwell Hardness
A Scale
B Scale
C Scale

--

85.6

--

68.0

--

85.3

--

67.5

--

85.0

--

67.0

767

84.7

--

66.4

757

84.4

--

65.9

745

84.1

--

65.3

733

83.8

--

64.7

722

83.4

--

64.0

712

--

--

--

710

83.0

--

63.3

698

82.6

--

62.5

684

82.2

--

61.8

682

82.2

--

61.7

670

81.8

--

61.0

656

81.3

--

60.1

653

81.2

--

60.0

647

81.1

--

59.7

638

80.8

--

59.2

630

80.6

--

58.8

627

80.5

--

58.7

601

79.8

--

57.3

578

79.1

--

56.0

555

78.4

--

54.7

534

77.8

--

53.5

514

76.9

--

52.1

495

76.3

--

51.0

477

75.6

--

49.6

461

74.9

--

48.5

444

74.2

--

47.1

429

73.4

--

45.7

415

72.8

--

44.5

401

72.0

--

43.1

388

71.4

--

41.8

375

70.6

--

40.4

363

70.0

--

39.1

352

69.3

--

37.9

341

68.7

--

36.6

 

Brinell Hardness 
Rockwell Hardness
A Scale
B Scale
C Scale

331

68.1

--

35.5

321

67.5

--

34.3

311

66.9

--

33.1

302

66.3

--

32.1

293

65.7

--

30.9

285

65.3

--

29.9

277

64.6

--

28.8

269

64.1

--

27.6

262

63.6

--

26.6

255

63.0

--

25.4

248

62.5

--

24.2

241

61.8

100.0

22.8

235

61.4

99.0

21.7

229

60.8

98.2

20.5

223

--

97.3

20.0

217

--

96.4

18.0

212

--

95.5

17.0

207

--

94.6

16.0

201

--

93.8

15.0

197

--

92.8

--

192

--

91.9

--

187

--

90.7

--

183

--

90.0

--

179

--

89.0

--

174

--

87.8

--

170

--

86.8

--

167

--

86.0

--

163

--

85.0

--

156

--

82.9

--

149

--

80.8

--

143

--

78.7

--

137

--

76.4

--

131

--

74.0

--

126

--

72.0

--

121

--

69.8

--

116

--

67.6

--

111

--

65.7

--

 

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