Hardness conversion chart
Convert the hardness of steel between Rockwell C (HRC), Rockwell B (HRB), Brinell (HB) and Vickers (HV), with an estimate of tensile strength.
That's about the same as spring steel.
What it means
How hard is that?
For carbon and alloy steels (ASTM E140). Conversions between scales are approximate; for other metals and for exact values, test on the scale you need.
Every unit
That hardness on every scale
Learn
Three things worth knowing
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HB × 3.45 ≈ MPa
For steel, tensile strength in MPa is about 3.45 times the Brinell number (500 psi per point): HB 300 is about 1,035 MPa.
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Three tests, three eras
Johan Brinell showed his ball test in Paris in 1900; the Rockwell brothers patented their depth tester in 1919 for ball bearings; Vickers engineers devised the diamond pyramid in 1921.
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Not for every metal
These tables are for steel. Aluminium, brass or cast iron convert differently, and HRC below 20 or HRB above 100 are outside their scales.
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Background
About hardness scales
Hardness tests press a hard tip into the metal and measure the dent. Vickers uses a diamond pyramid and works on everything; Brinell a 10 mm ball, for castings and soft steel; Rockwell measures depth, quickly: the C scale with a diamond cone for hardened steel, the B scale with a ball for softer metal.
Since the dents differ, no formula links the scales. Standards publish tables measured on steel, and this converter interpolates them.