Calculator
Formula Used
This calculator uses table interpolation. The conversion is not a universal direct equation.
HRC = HRC low + (HV - HV low) × (HRC high - HRC low) / (HV high - HV low)
Final HRC = interpolated HRC + offset correction
The lower and upper points are selected from the internal HV to HRC reference table.
How to Use This Calculator
- Enter the Vickers hardness value in HV.
- Add a sample name if you need a report label.
- Choose decimal places for the final Rockwell C value.
- Add an offset only when your quality method requires it.
- Enable extrapolation only for rough estimates outside the table range.
- Press calculate and review the result above the form.
- Use CSV or PDF export for records.
Example Data Table
| Vickers HV | Rockwell C HRC | Typical Use Note |
|---|---|---|
| 238 | 20 | Lower hardened steel range |
| 302 | 30 | Moderate hardness comparison |
| 392 | 40 | Common heat treated steel range |
| 513 | 50 | Higher strength tool applications |
| 697 | 60 | Very hard steel comparison |
| 832 | 65 | High hardness tooling zone |
| 900 | 67 | Near upper practical range |
| 940 | 68 | Upper listed table point |
Vickers to Rockwell C Conversion Guide
Hardness Conversion Basics
Hardness conversion helps teams compare reports from different test methods. Vickers hardness uses a diamond pyramid and a measured diagonal. Rockwell C uses a diamond cone and a depth reading. Both methods describe resistance to indentation. They do not measure the same physical response. That is why a conversion table is needed.
Why This Calculator Helps
Many steel certificates show HV values. Many drawings, heat treatment plans, and shop limits use HRC values. This calculator bridges that gap. It uses a reference conversion table and linear interpolation between known points. The result is useful for screening, documentation, and early planning. It should not replace a formal hardness test when acceptance rules require a specific scale.
How Interpolation Works
The tool finds the two closest Vickers values in the internal table. It then estimates the Rockwell C value between them. This method is smooth and practical. It avoids large jumps between table rows. If the value is outside the supported range, the calculator warns the user. Extrapolation can be enabled, but it should be used carefully.
Best Use Cases
Use this calculator for hardened steels, tool steels, alloy steels, and heat treated parts. It is helpful when checking quench results, comparing vendor certificates, or preparing inspection notes. It also helps learners understand how HV and HRC relate across common hardness levels.
Limits You Should Know
Hardness conversion depends on material behavior, test load, surface finish, and case depth. Thin coatings, soft metals, welded zones, and rough surfaces can create misleading conversions. Standards may also use different conversion tables. Always follow the table required by your specification, purchase order, or quality plan.
Practical Tips
Clean the test surface before measuring hardness. Use enough readings to represent the part. Avoid edges and curved areas when possible. Record the original HV value with the converted HRC value. Keep the selected precision and offset in your notes. This makes later reviews easier and clearer.
Quality Reminder
Use converted values as engineering guidance, not final proof. Confirm critical parts with the required test method. This is important for safety parts, aerospace work, tooling, dies, shafts, and customer inspections. Good records reduce disputes and help teams repeat successful heat treatment results.
FAQs
What does this calculator convert?
It converts Vickers hardness values into estimated Rockwell C values using table interpolation. It is mainly useful for steel hardness comparison and inspection planning.
Is HV to HRC a direct formula?
No. HV and HRC use different test methods. This calculator uses reference table points and linear interpolation to estimate the equivalent value.
What HV range is supported?
The default table supports 238 HV to 940 HV. These values correspond to about 20 HRC to 68 HRC in the calculator.
Should I allow extrapolation?
Use extrapolation only for rough estimates. Values outside the table range may not represent real material behavior accurately.
What is the offset correction field?
The offset lets you add or subtract a known correction. Use it only when your internal method or inspection rule requires adjustment.
Can this replace laboratory testing?
No. It is a comparison tool. Use the required hardness test method when specifications, audits, or acceptance rules demand direct measurement.
Why can converted hardness values differ?
Differences happen because material type, test force, surface finish, thickness, and microstructure affect hardness readings and conversions.
Can I export the result?
Yes. After calculation, use the CSV or PDF buttons to save the result, table bracket, method, and material note.