Hardness Testing: Rockwell, Brinell and Vickers Explained

When a drawing calls for “58–62 HRC” or “200 HB,” it is specifying hardness — a part’s resistance to permanent indentation, and a quick proxy for strength, wear resistance and whether a heat treatment worked. Hardness is one of the most common things measured on a precision part, and there are three main scales: Rockwell, Brinell and Vickers. This guide explains what hardness tells you, how each test works, and how to specify the right one.

Why Hardness Matters

Hardness is fast, cheap and non-destructive, and it correlates with properties that matter: a harder steel generally resists wear better and is stronger, while a softer one machines more easily. Most importantly, hardness is how you verify a heat treatment — after hardening and tempering, a hardness check confirms the part reached the intended condition. That is why so many drawings carry a hardness callout alongside the material. See our heat treatment guide.

The Three Main Tests

All three press a defined indenter into the surface under a set load and measure the indentation — they just do it differently.

Rockwell is the everyday workshop test — quick, direct-reading, and the usual way hardened steel (HRC) is checked. Brinell uses a big ball and a big indent, so it averages over a large area — ideal for castings and forgings whose structure is coarse. Vickers uses a diamond pyramid and is the most precise and versatile, covering everything from soft metals to hard coatings, and it’s the test for thin sections, surface layers and case-hardening depth.

Reading a Hardness Callout

A callout names the scale and value: HRC (Rockwell C, hardened steel), HRB (Rockwell B, softer metals), HB/HBW (Brinell), HV (Vickers). For example, “60 HRC” means a hard tool-steel condition; “200 HB” a medium-hard casting. The scales relate to one another through conversion tables, but they are not identical tests — so specify the scale your inspection equipment actually uses, and don’t mix converted values into a tight tolerance.

Specifying Hardness on a Part

• Pick the scale that fits the part. Hardened steel → HRC; castings/forgings → HB; thin parts, coatings or case depth → HV.
• Give a range, not a single number (e.g. 58–62 HRC) — heat treatment has natural spread, and a single value is impossible to hit.
• Say where to measure on case-hardened parts — surface hardness and core hardness differ, so call out both if they matter.
• Match hardness to function. Higher hardness resists wear but is more brittle; balance it against toughness, as in heat-treat tempering.
• Pair it with the right material — tool steel reaches high HRC, mild steels do not. Inspection ties into our wider quality standards.

The Bottom Line

Hardness is the quick, reliable check that a part is as strong, wear-resistant and correctly heat-treated as the drawing demands. Rockwell is the fast shop standard, Brinell suits coarse castings and forgings, and Vickers is the precise test for thin parts, coatings and case depth. Choose the scale that fits the part, specify a realistic range rather than a single number, and state where to measure on case-hardened components. Done right, a hardness callout turns “it should be hard enough” into a number you can verify on every part.

MechPart Pro hardness-tests to Rockwell, Brinell and Vickers and documents results with your inspection report, confirming every heat-treated part meets its specified range. Share your drawing and target hardness and our quality team will verify it as part of our process. Explore hardenable alloys in our materials guide.