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Hardness Scale Conversion Chart

Reference chart for converting between different hardness scales (Rockwell, Brinell, Vickers, Knoop)

Hardness Scale Conversion Chart

Metallography.org - Free Educational Resources

HRCHRBHBHVHKHRA
20-22522622760.0
21-22923023160.2
22-23423523660.4
23-23823924060.6
24-24324424560.8
25-24824925061.0
26-25325425561.2
27-25825926061.4
28-26326426561.6
29-26927027161.8
30-27527627762.0
31-28128228362.2
32-28828929062.4
33-29529629762.6
34-30230330462.8
35-31031131263.0
36-31831932063.2
37-32732832963.4
38-33633733863.6
39-34534634763.8
40-35535635764.0
41-36536636764.2
42-37637737864.4
43-38838939064.6
44-40040140264.8
45-41341441565.0
46-42742842965.2
47-44244344465.4
48-45845946065.6
49-47547647765.8
50-49349449566.0
51-51351451566.2
52-53453553666.4
53-55755855966.6
54-58258358466.8
55-60961061167.0
56-63863964067.2
57-67067167267.4
58-70570670767.6
59-74474574667.8
60-78778878968.0
61-83583683768.2
62-88989089168.4
63-95095195268.6
64-10201021102268.8
65-11001101110269.0
66-11901191119269.2
67-12901291129269.4
68-14101411141269.6
69-15501551155269.8
70-17201721172270.0

Notes

  • • HRC: Rockwell C scale (diamond cone, 150 kgf) - for hard materials
  • • HRB: Rockwell B scale (1/16" ball, 100 kgf) - for softer materials
  • • HB: Brinell Hardness (10mm ball, 3000 kgf)
  • • HV: Vickers Hardness (diamond pyramid indenter)
  • • HK: Knoop Hardness (elongated diamond pyramid)
  • • HRA: Rockwell A scale (diamond cone, 60 kgf) - for very hard materials
  • • Conversions are approximate; actual values may vary slightly between materials
  • • Always verify with direct measurement when accuracy is critical
  • • For precise conversions, refer to ASTM E140 standard conversion tables