Steel Hardness Converter

Instantly convert between Rockwell C (HRC), Brinell (HB), and Vickers (HV) scales.

This conversion is based on ASTM A370 Table 2 and 3, and is typical representative for non-austenitic steels. The conversion may be less accurate for austenitic steels and other alloys, and should be used for info only.

Common Hardness Conversion Table

Use this quick reference chart to compare the most common hardness scales used in the offshore and marine industries, based on ASTM A370 standards.

Standard Reference

ASTM A370 / ISO 18265

(Values are approximate conversions for non-austenitic steels)

Rockwell C (HRC)	Brinell (HB)	Vickers (HV)
20 HRC	226 HB	238 HV
25 HRC	253 HB	266 HV
28 HRC (NACE Limit)	271 HB	286 HV
32 HRC	301 HB	318 HV
40 HRC	371 HB	392 HV
50 HRC	481 HB	513 HV

Often asked about

What is the difference between Brinell and Rockwell?

Brinell (HB) uses a ball indenter and is better for softer or heterogeneous materials. Rockwell C (HRC) uses a diamond cone and is standard for hard, heat-treated steels.
Why is maximum hardness important (NACE)?

In sour service (H2S) environments, steel that is too hard becomes brittle and susceptible to cracking (SCC). NACE MR0175 standards therefore limit hardness. For example, Duplex Stainless Steel is typically limited to max 28 HRC.

Note: For NACE MR0175 compliance (Sour Service), ensure hardness does not exceed the specified limits. For further questions, contact our technical team today.
Can I convert Hardness to Tensile Strength?

Yes, there is a strong correlation for carbon and low-alloy steels. The rule of thumb is: Tensile Strength (MPa) ≈ 3.5 × Brinell Hardness (HB).

Ingve Stangeland

Technical Manager

+47 900 66 062 ingve.stangeland@sverdrupsteel.com

Steel Hardness Converter

Common Hardness Conversion Table

Often asked about

What is the difference between Brinell and Rockwell?

Why is maximum hardness important (NACE)?

Can I convert Hardness to Tensile Strength?

Ingve Stangeland