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Hardness Converter - ASTM E140 HRC/HRB/HB/HV & Tensile Strength Conversion

Convert between Rockwell C, Rockwell B, Brinell, Vickers, and approximate tensile strength per ASTM E140

Check local hardness conversion rows for Rockwell C (HRC), Rockwell B (HRB), Brinell (HB), Vickers (HV), and approximate tensile strength in ksi. The rows are local ToolGrit planning fixtures, not a licensed or independently verified reproduction of current ASTM E140 or ISO 18265 tables. Use the output for shop planning only, then confirm the required scale and method against the drawing, material spec, heat-treat procedure, current standard, calibrated tester, and qualified review.

Pro Tip: If the print or purchase order calls for HRC, test HRC. If it calls for HBW, test HBW. Converting from another scale adds uncertainty and may not be accepted. Conversions depend on material group, heat treatment, surface prep, part thickness, indenter, load, and tester verification.

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Material Hardness Converter
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How It Works

  1. Select Input Scale

    Choose the measured scale: HRC, HRB, HB, HV, or tensile estimate. The app displays the local fixture range for that scale.

  2. Enter Your Hardness Value

    Enter the measured value. The app warns when the input falls outside the local fixture range and does not extrapolate out-of-range conversions.

  3. Review Converted Values

    Use the converted values as an estimate only. Report and PDF output carry the same source-boundary warnings shown in the app.

  4. Check Source Pointers

    Review the ASTM E140, ASTM E18, ASTM E10, ASTM E92, ASTM E384, and ISO 18265 pointers before using results for acceptance or specification work.

Built For

  • Quality inspectors doing a preliminary check before formal material or heat-treat acceptance
  • Millwrights and machinists selecting cutting tools and feeds based on workpiece hardness
  • Welding engineers screening heat-affected-zone hardness before standard-specific review
  • Metallurgists comparing approximate hardness correlations before selecting the correct test method
  • Purchasing agents checking whether a mill cert or supplier value needs direct scale verification
  • Maintenance techs field-testing shaft, gear, and bearing hardness with portable testers
  • Failure analysts correlating component hardness to tensile strength for root cause determination

Features & Capabilities

Local Conversion Fixtures

The app preserves local legacy rows for HRC, HRB, HB, HV, and tensile estimate screening. These rows remain source-gap fixtures until checked against authorized current standards.

Four Hardness Scales

Screens Rockwell C, Rockwell B, Brinell, and Vickers values plus an approximate tensile-strength field in ksi. It does not output Knoop, HRA, superficial Rockwell, Scleroscope, or Leeb values.

Range Guarding

Out-of-range inputs are flagged and are not extrapolated. The local ranges are shown in the app so users can see the boundary being applied.

Source-Boundary Export

CSV and PDF exports carry source warnings, assumptions, and official source pointers so the limitation follows the saved calculation.

Comparison

Hardness Scale Indenter Load Typical Range Best Application
Rockwell C (HRC) Diamond cone 150 kgf major load Local app fixture: 20-68 HRC Hardened-steel screening only unless the required method/spec is verified
Rockwell B (HRB) Ball indenter 100 kgf major load Local app fixture: 60-100 HRB Softer-material screening only unless the material group and method are verified
Brinell (HB) Ball indenter Load depends on method/material Local app fixture: 81-694 HB Large-impression screening only; verify HBW method and material spec
Vickers (HV) Diamond pyramid Force depends on method Local app fixture: 107-940 HV Lab or micro/macro hardness screening only; verify method and uncertainty
Tensile estimate Derived correlation Not a hardness test Local app fixture: 45-370 ksi Screening proxy only; not tensile-test data or allowable stress

Assumptions

  • Local conversion rows are planning fixtures and are not a licensed table reproduction.
  • Linear interpolation is used between local rows.
  • Test specimen, material group, surface prep, part thickness, force, indenter, and tester verification still need review.
  • Tensile estimate rows are screening proxies only.

Limitations

  • Not proof of material certification, heat-treatment acceptance, drawing compliance, purchase acceptance, weld or NACE compliance, or failure-analysis conclusions.
  • Not valid for unsupported material groups unless current material-specific conversion data is verified.
  • Does not output Knoop, HRA, superficial Rockwell, Scleroscope, or Leeb values.
  • Portable hardness tester readings may not correlate with bench tester conversions.
  • Does not account for case-hardened surfaces where core and surface hardness differ.

References

  • ASTM E140 - Standard Hardness Conversion Tables for Metals official source pointer.
  • ASTM E18 - Standard Test Methods for Rockwell Hardness of Metallic Materials official source pointer.
  • ASTM E10 - Standard Test Method for Brinell Hardness of Metallic Materials official source pointer.
  • ASTM E92 - Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials official source pointer.
  • ASTM E384 - Standard Test Method for Microindentation Hardness of Materials official source pointer.
  • ISO 18265 - Metallic materials conversion of hardness values official source pointer.

Frequently Asked Questions

HRC and HRB are different Rockwell scales with different indenters and loads. A number without the scale letters is not meaningful. Use the scale required by the drawing, material standard, or quality procedure.
They are approximate empirical correlations, not exact equations. Accuracy depends on material group, heat treatment, test method, surface prep, thickness, tester verification, and the selected conversion table.
Only if the conversion table or producer data applies to that material group and condition. Austenitic stainless, aluminum, copper alloys, cast iron, hardmetals, coatings, and case-hardened parts often need direct testing or material-specific data.
No. The tensile field is a screening proxy from local hardness-correlation rows. It is not tensile-test data, a material certification, or a design allowable.
Use the test method required by the applicable spec. Brinell is often used for stock, forgings, and castings where a larger impression helps average local variation. Rockwell is common for production checks on finished and heat-treated parts.
Portable testers (Leeb rebound, UCI ultrasonic) measure a different physical property than standard bench testers and convert to HRC/HRB/HB using built-in algorithms. Accuracy depends on surface finish (must be ground smooth), coupling gel application, part mass (small or thin parts give false readings), and calibration. Portable testers are convenient for field work but are not substitutes for bench-mounted Rockwell or Brinell testers for acceptance testing per material specifications.
It depends on alloy, section size, heat-treat cycle, tempering temperature, and acceptance spec. Use local range rows only as a planning prompt, then check the mill cert, heat-treat record, and material specification.
Disclaimer: This converter uses local source-gap conversion fixtures. It does not reproduce protected ASTM or ISO tables, certify material properties, approve heat treatment, or determine drawing or purchase-order compliance. Verify critical hardness requirements using the required standard method and qualified review.

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