Convert hardness between Rockwell (HRC), Vickers (HV) and Brinell (HB), with a tensile strength estimate.
HRC
HV
HB
Rm (MPa)
20
238
226
770
25
266
253
850
30
302
286
950
35
345
327
1,080
40
392
371
1,250
45
446
421
1,450
48
484
455
1,580
50
513
481
1,680
52
544
—
—
55
595
—
—
58
653
—
—
60
697
—
—
63
772
—
—
65
832
—
—
Approximate values for un-/low-alloy steel (ISO 18265). Above ~450 HB, Brinell is unreliable; the Rm estimate holds to ~50 HRC.
How do you convert hardness?
Hardness is measured on several scales: Rockwell C (HRC), Vickers (HV) and Brinell (HB). They measure the same property with a different indenter and load, so conversion is always an approximation (per ISO 18265 / SAE J417, for steel). Rule of thumb: HV ≈ HB up to ~450, and Rm ≈ 3.3 × HB for unhardened steel. For hard materials (>450 HB), use HV or HRC; Brinell is no longer reliable there.
Frequently asked questions
How much HV is 50 HRC?
About 513 HV. Conversely, 500 HV is roughly 49 HRC.
Why only an approximation?
Each method uses a different indenter and force. The conversion holds statistically for steel; other alloys deviate.
Can I derive strength from hardness?
For unhardened steel, Rm ≈ 3.3 × HB is a rough estimate. Above ~50 HRC that relationship is no longer linear.
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