Conversion Result
Advanced Rockwell Hardness Converter
Example Data Table
| Sample | Input | Approx HRC | Approx HRB | Approx HV | Approx HB | Approx UTS MPa |
|---|---|---|---|---|---|---|
| Medium carbon steel | 25 HRC | 25 | 102 | 266 | 247 | 858 |
| Hardened tool steel | 60 HRC | 60 | 147 | 697 | 649 | 2251 |
| Mild steel estimate | 90 HRB | 16 | 90 | 196 | 182 | 632 |
Formula Used
Hardness conversions are not exact physical equations. They are practical estimates based on comparison tables. This calculator first converts the selected input into an approximate Vickers value. Then it derives other values from that estimated Vickers base.
Approximate relations used here are:
- HV from HRC: HV = 95 + 10.04HRC + 0.027HRC²
- HRC from HV: solved by reverse lookup over a practical range
- HRB from HRC: HRB = 70 + 1.28HRC
- HB estimate: HB = HV / 1.075
- Ultimate tensile strength: MPa = HB × 3.47
- Allowable estimate: MPa × strength allowance factor
Use the result for planning, education, and screening. For acceptance testing, use the material specification, calibrated instruments, and the required standard conversion table.
How to Use This Calculator
- Enter the known hardness value.
- Select the scale of the entered value.
- Choose the material group closest to the tested part.
- Add the load note, sample ID, operator, and comments.
- Set decimal places and the strength allowance factor.
- Press the calculate button.
- Review the result above the form.
- Export the result as CSV or PDF when needed.
Rockwell Hardness Test Conversion Guide
Why Conversion Is Useful
Rockwell hardness testing is common in shops, labs, and inspection rooms. It gives a fast reading from an indentation depth. Many drawings use HRC for hardened steel. Others use HRB, Brinell, Vickers, or tensile strength. A conversion calculator helps compare those numbers quickly. It is useful when a supplier report uses one scale and a drawing uses another.
What This Tool Estimates
This calculator converts a single reading into several related estimates. It supports HRC, HRB, HRA, HV, HB, and tensile strength in MPa. It also adds an allowance factor. That factor helps users make a cautious working estimate. The result can be copied into an inspection note or downloaded for records.
Important Limits
Hardness conversion is never perfect. Each scale uses a different indenter, load, and measuring method. Material structure also matters. Heat treatment, cold work, carbon level, coating thickness, and case depth can change the relationship. Two parts with the same HRC value may not have the same tensile strength. Thin parts and curved parts can also produce misleading readings.
Better Testing Practice
Clean the surface before testing. Remove scale, rust, coating, and heavy marks. Support the part firmly. Keep enough distance between indentations. Avoid edges and thin sections. Take several readings when the part allows it. Then average the useful values. If the part is critical, confirm the conversion with the governing material standard.
Using the Results
The converted values are best used for comparison, sorting, early design checks, training, and report review. They should not replace a certified hardness table. They should not replace tensile testing for safety parts. Treat them as informed estimates. When tolerances are tight, use the exact scale required by the drawing. That is the safest approach for quality control.
FAQs
1. Is Rockwell hardness conversion exact?
No. Conversion is an estimate. Different test methods use different loads, indenters, and measurement principles. Use certified tables for final acceptance.
2. What is HRC used for?
HRC is often used for hardened steels, tool steels, dies, shafts, blades, and heat-treated parts where higher hardness is expected.
3. What is HRB used for?
HRB is often used for softer steels, copper alloys, aluminum alloys, brass, and other materials below the normal HRC range.
4. Can I convert hardness to tensile strength?
Yes, but only approximately. The common HB to MPa relation works best for many steels. It may fail for other materials.
5. Why do standards give different values?
Standards may use different test data, materials, and rounding rules. Always follow the standard named in your drawing or contract.
6. Can this calculator handle case hardened parts?
It can estimate values, but case depth matters. A shallow hard layer may not represent the core material strength.
7. Should I average several hardness readings?
Usually yes. Multiple readings reduce random error. Avoid damaged spots, edges, thin areas, and previous indentation zones.
8. Can I use these results for inspection release?
Use them only if your procedure allows estimated conversion. For formal release, follow calibrated testing and approved conversion standards.