Maker Label Studio Manufacturing & Materials | ASTM E140 / SAE J417 steel basis

Hardness Conversion Calculator (HB/HRC/HV)

Convert steel hardness among Brinell, Rockwell C, Rockwell B, Vickers, and approximate tensile strength using ASTM E140 / SAE J417-style table interpolation.

Recommended input range for HRC: 20 to 68.

Conversion Results

Basis: ASTM E140 / SAE J417 conversion tables for steel. Table values are interpolated linearly between listed points; Rockwell B is reported only in its lower-hardness table range.

Input 40 HRC
Vickers HV
392
Input converted through steel table.
Brinell HB
371
HBW/HBS steel-table equivalent.
Rockwell C
40.0
HRC table equivalent.
Rockwell B
Not reported
Above the Rockwell B table range.
Tensile Estimate
185.50 ksi / 1,278.98 MPa
Approximate steel UTS from Brinell hardness.
Output Value Status Notes

Range Notes

    Self-Tests

    Self-tests have not been run.

    About the Hardness Conversion Calculator (HB/HRC/HV)

    Hardness conversion gives metallurgists, machinists, inspectors, and buyers a practical way to compare HB, HRC, HRB, and HV values when drawings or test reports use different scales. The calculator follows published conversion tables where applicable and flags that conversions are approximate because material, heat treatment, and test method affect the relationship.

    How it works

    1. Choose the known hardness scale and enter the measured value.
    2. Select the material family if the calculator offers a material-specific table.
    3. Review approximate converted values across supported scales.
    4. Use the result for comparison, not as a substitute for required testing.

    Frequently asked questions

    Are hardness conversions exact?

    No. Conversion tables are empirical and approximate. The relationship between scales changes with alloy, microstructure, heat treatment, and test conditions.

    Can I convert HRC to HB for any metal?

    Only within the range and material class covered by a recognized table. Conversions outside the table range or across very different materials can be misleading.

    Is tensile strength from hardness reliable?

    It is only an estimate and is most defensible for steels within the applicable standard ranges. It should not replace tensile testing when a specification requires it.

    Which hardness scale should a drawing specify?

    The drawing should specify the required test method, scale, load, acceptance range, and standard. A converted value alone is not ideal for inspection control.

    Why do Rockwell B and Rockwell C overlap poorly?

    They use different indenters and loads and are intended for different hardness ranges. Near the ends of a scale, measurement uncertainty and conversion error increase.

    References