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Rockwell to Brinell Hardness Conversion Chart

In this blog post, you’ll read:Converting Rockwell hardness to Brinell hardness scale requires a conversion table created using a carefully calculated formula to get an equivalent hardness value. This is the Rockwell to Brinell Hardness conversion chart for you.

Table of Contents

Brinell hardness testing is a common method manufacturers, and engineers use to ascertain the hardness of metal components and materials during the design and manufacturing of these materials. But the tools and equipment available might be for a different test like the Rockwell hardness test. The challenge then becomes getting an equivalent hardness value from a Rockwell hardness value. Consequently, designers and engineers often turn to hardness conversion tables and charts to interpret a hardness value from one hardness testing to the other. 

 

Rockwell to Brinell Hardness Conversion Chart

 

I. What is Rockwell Hardness?

Rockwell hardness testing is a destructive testing method used to determine the tensile strength of a material using an indenter and a set of known loads. The indenter is usually made of steel and can have a ball or conical shape depending on the material tested. Also, depending on the thickness of the material, the load often ranges from 60kg to 150kg. Additionally, the depression caused by the indenter is usually measured and used in a formula to calculate the hardness value of the material. These hardness values can be represented in different scales and converted to values of a different hardness testing method. 

Related Article: What are the Advantages and Disadvantages of the Rockwell Method

 

II. What is Brinell Hardness? 

Brinell hardness often requires an indenter ball of hardened steel with a 10mm diameter to cause an indentation on the test material. The weight of this indenter ball is usually 3,000kgf, and it measures the hardness of both soft and hard materials. However, the Brinell hardness test requires an optical instrument like a microscope to determine the indentation on the material caused by the ball indenter.

Related Article: What are the Advantages and Disadvantages of the Brinell Method

 

III. What is the Difference between Rockwell and Brinell?

Various features differentiate Rockwell and Brinell hardness testing apart. While some are obvious, others are not immediately noticeable and need some digging to identify these differences. These differences include

  • Both indenters are different, with a 10mm ball indenter used in Brinell testing and a cone-shaped indenter with a diamond tip for Rockwell testing. 
  • The hardness values are also different for both hardness testing methods. That’s why a conversion chart is often required to get an equivalent hardness value for the Brinell hardness value when professionals carry out the Rockwell test and vice versa. 
  • Where the Rockwell test directly measures the indentation on the material, the Brinell test often requires an optical instrument to measure the indentation. 

 

IV. Can you Convert Rockwell to Brinell?

Using a standard formula, it is possible to get equivalent values of Brinell hardness tests from a Rockwell hardness test. This formula also helps to create a conversion table popular in the hardness testing industry for instantly converting between the two hardness tests. However, it is good to note that these conversion formulas and tables only give approximate values but are accurate within tolerable error boundaries. 

Related Article: Hardness Test Comparison: Rockwell vs Brinell

Related Article: Rockwell C to Brinell Hardness Conversion Chart

 

V. How do you Convert HRC to BHN?

Using charts and formulas helps designers and engineers convert the hardness value they get from one hardness test to the required hardness test value. For instance, converting from a Rockwell hardness test on the C scale (HRC) to a Brinell hardness test value requires using the formula: BHN = 5.970 x (HRC + 104.7). This formula gives an approximate value for the Brinell hardness value, and quality assessment professionals use it to create the conversion tables and charts for instant conversion.

 

VI. Rockwell to Brinell Hardness Conversion Chart

Rockwell Hardness

Brinell Hardness

HRA

60kg Brale

HRB

100kg 1/16″ Ball

HRC

150kg Brale

HRD

100kg Brale

HRE

100kg 1/8″ Ball

HRF

60kg 1/16″ Ball

3,000kg

10mm Steel Ball

500kg

10mm Steel Ball

86.5

70

78.5

86.0

69

77.7

85.6

68

76.9

85.0

67

76.1

84.5

66

75.4

83.9

65

74.5

739

83.4

64

73.8

722

82.8

63

73.0

705

82.3

62

72.2

688

81.8

61

71.5

670

81.2

60

70.7

654

80.7

59

69.9

634

80.1

58

69.2

615

79.6

57

68.5

595

79.0

56

67.7

577

78.5

120

55

66.9

560

78.0

120

54

66.1

543

77.4

119

53

65.4

525

76.8

119

52

64.6

500

76.3

118

51

63.8

487

75.9

117

50

63.1

475

75.2

117

49

62.1

464

74.7

116

48

61.4

451

74.1

116

47

60.8

442

73.6

115

46

60.0

432

73.1

115

45

59.2

421

72.5

114

44

58.5

409

72.0

113

43

57.7

400

71.5

113

42

56.9

390

70.9

112

41

56.2

381

70.4

112

40

55.4

371

69.9

111

39

54.6

362

69.4

110

38

53.8

353

68.9

110

37

53.1

344

68.4

109

36

52.3

336

67.9

109

35

51.5

327

67.4

108

34

50.8

319

66.8

108

33

50.0

311

66.3

107

32

49.2

301

65.8

106

31

48.4

294

65.3

105

30

47.7

286

64.7

104

29

47.0

279

64.3

104

28

46.1

271

63.8

103

27

45.2

264

63.3

103

26

44.6

258

62.8

102

25

43.8

253

62.4

101

24

43.1

247

62.0

100

23

42.1

240

201

61.5

99

22

41.6

234

195

61.0

98

21

40.9

228

189

60.5

97

20

40.1

222

184

59.0

96

18

216

179

58.0

95

16

210

175

57.5

94

15

205

171

57.0

93

13

200

167

56.5

92

12

195

163

56.0

91

10

190

160

55.5

90

9

185

157

55.0

89

8

180

154

54.0

88

7

176

151

53.5

87

6

172

148

53.0

86

5

169

145

52.5

85

4

165

142

52.0

84

3

162

140

51.0

83

2

159

137

50.5

82

1

156

135

50.0

81

0

153

133

49.5

80

150

130

49.0

79

147

128

48.5

78

144

126

48.0

77

141

124

47.0

76

139

122

46.5

75

99.5

137

120

46.0

74

99.0

135

118

45.5

73

98.5

132

116

45.0

72

98.0

130

114

44.5

71

100.0

97.5

127

112

44.0

70

99.5

97.0

125

110

43.5

69

99.0

96.0

123

109

43.0

68

98.0

95.5

121

107

42.5

67

97.5

95.0

119

106

42.0

66

97.0

94.5

117

104

41.8

65

96.0

94.0

116

102

41.5

64

95.5

93.5

114

101

41.0

63

95.0

93.0

112

99

40.5

62

94.5

92.0

110

98

40.0

61

93.5

91.5

108

96

39.5

60

93.0

91.0

107

95

39.0

59

92.5

90.5

106

94

38.5

58

92.0

90.0

104

92

38.0

57

91.0

89.5

102

91

37.8

56

90.5

89.0

101

90

37.5

55

90.0

88.0

99

89

37.0

54

89.5

87.5

87

36.5

53

89.0

87.0

86

36.0

52

88.0

86.5

85

35.5

51

87.5

86.0

84

35.0

50

87.0

85.5

83

34.8

49

86.5

85.0

82

34.5

48

85.5

84.5

81

34.0

47

85.0

84.0

80

33.5

46

84.5

83.0

79

33.0

45

84.0

82.5

79

32.5

44

83.5

82.0

78

32.0

43

82.5

81.5

77

31.5

42

82.0

81.0

76

31.0

41

81.5

80.5

75

30.8

40

81.0

79.5

74

30.5

39

80.0

79.0

74

30.0

38

79.5

78.5

73

29.5

37

79.0

78.0

72

29.0

36

78.5

77.5

71

28.5

35

78.0

77.0

71

28.0

34

77.0

76.5

70

27.8

33

76.5

75.5

69

27.5

32

76.0

75.0

68

27.0

31

75.5

74.5

68

26.5

30

75.0

74.0

67

26.0

29

74.0

73.5

66

25.5

28

73.5

73.0

66

25.0

27

73.0

72.5

65

24.5

26

72.5

72.0

65

24.2

25

72.0

71.0

64

24.0

24

71.0

70.5

64

23.5

23

70.5

70.0

63

23.0

22

70.0

69.5

63

22.5

21

69.5

69.0

62

22.0

20

68.5

68.5

62

21.5

19

68.0

68.0

61

21.2

18

67.5

67.0

61

21.0

17

67.0

66.5

60

20.5

16

66.5

66.0

60

20.0

15

65.5

65.5

59

14

65.0

65.0

59

13

64.5

64.5

58

12

64.0

64.0

58

11

63.5

63.5

57

10

62.5

63.0

57

9

62.0

62.0

56

8

61.5

61.5

56

7

61.0

61.0

56

6

60.5

60.5

55

5

60.0

60.0

55

4

59.0

59.5

55

3

58.5

59.0

54

2

58.0

58.0

54

1

57.5

57.5

53

0

57.0

57.0

53

Conclusion

In conclusion, converting Rockwell hardness to Brinell hardness scale requires a conversion table created using a carefully calculated formula to get an equivalent hardness value. However, you need to know that it is an approximate value with very high accuracy. This conversion will often help when the testing equipment available is one for Rockwell while the required hardness testing scale is a Brinell scale and vice versa.