Free Hardness Conversion Calculator

Approximate conversion between Brinell hardness (HB) and ultimate tensile strength using the empirical relationship.

Approx. UTS (steel)

690 MPa

Approx. UTS100.1 ksi
Approx. Rockwell B (HRB)88.9

Approx. UTS (steel) vs Brinell Hardness (HB)

Hardness to Strength Conversion

For carbon and alloy steels, Brinell hardness (HB) correlates approximately with ultimate tensile strength.

Empirical Relationship

UTS (MPa) ≈ 3.45 × HB

This approximation is valid for steels in the range HB 120-450. For non-ferrous metals or very high-strength steels, the conversion factor differs. The Rockwell B approximation is a rough linear mapping useful for quick estimates.

Example Calculation

A steel part has a measured Brinell hardness of 200 HB.

  1. 01UTS ≈ 3.45 × 200 = 690 MPa
  2. 02In ksi: 690 × 0.145 = 100.1 ksi
  3. 03Approx. HRB = (200 - 49) / 2.8 + 35 = 53.9 + 35 = 88.9

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