Hardness to Tensile Strength Conversion
Understanding the Hardness-Strength Correlation
A hardness to tensile strength conversion table is an essential resource for engineers, metallurgists, and fabrication specialists. It provides a quick reference for understanding the direct tensile strength hardness correlation in common metals. The conversion table below allows you to easily find the approximate ultimate tensile strength (UTS) from Rockwell (HRC, HRB) and Brinell (HB) readings, with values in PSI.
| Brinell Hardness | Rockwell Hardness | |||
|---|---|---|---|---|
| Tungsten Carbide Ball 3000 kg | A Scale 60 kg | B Scale 100 kg | C Scale 150 kg | Tensile Strength (approx.) |
| - | 86 | - | 68 | - |
| - | 85 | - | 68 | - |
| - | 85 | - | 67 | - |
| 767 | 84 | - | 66 | - |
| 757 | 84 | - | 66 | - |
| 745 | 84 | - | 65 | - |
| 733 | 84 | - | 65 | - |
| 722 | 83 | - | 64 | - |
| 712 | - | - | - | - |
| 710 | 83 | - | 63 | - |
| 698 | 83 | - | 62 | - |
| 684 | 82 | - | 62 | - |
| 682 | 82 | - | 62 | - |
| 670 | 82 | - | 61 | - |
| 656 | 81 | - | 60 | - |
| 653 | 81 | - | 60 | - |
| 647 | 81 | - | 60 | - |
| 638 | 81 | - | 59 | 329,000 |
| 630 | 81 | - | 59 | 324,000 |
| 627 | 80 | - | 59 | 323,000 |
| 601 | 80 | - | 57 | 309,000 |
| 578 | 79 | - | 56 | 297,000 |
| 555 | 78 | - | 55 | 285,000 |
| 534 | 78 | - | 54 | 274,000 |
| 514 | 77 | - | 52 | 263,000 |
| 495 | 76 | - | 51 | 253,000 |
| 477 | 76 | - | 50 | 243,000 |
| 461 | 75 | - | 48 | 235,000 |
| 444 | 74 | - | 47 | 225,000 |
| 429 | 73 | - | 46 | 217,000 |
| 401 | 72 | - | 43 | 202,000 |
| 388 | 71 | - | 42 | 195,000 |
| 375 | 71 | - | 40 | 188,000 |
| 363 | 70 | - | 39 | 182,000 |
| 352 | 69 | - | 38 | 176,000 |
| 341 | 69 | - | 37 | 170,000 |
| 331 | 68 | - | 36 | 166,000 |
| 321 | 68 | - | 34 | 160,000 |
| 311 | 67 | - | 33 | 155,000 |
| 302 | 66 | - | 32 | 150,000 |
| 293 | 66 | - | 31 | 145,000 |
| 285 | 65 | - | 30 | 141,000 |
| 277 | 65 | - | 29 | 137,000 |
| 269 | 64 | - | 28 | 133,000 |
| 262 | 64 | - | 27 | 129,000 |
| 255 | 63 | - | 25 | 126,000 |
| 248 | 62 | - | 24 | 122,000 |
| 241 | 62 | 100 | 23 | 118,000 |
| 235 | 61 | 99 | 22 | 115,000 |
| 229 | 61 | 98 | 20 | 111,000 |
| 223 | - | 97 | 20 | - |
| 217 | - | 96 | 18 | 105,000 |
| 212 | - | 96 | 17 | 102,000 |
| 207 | - | 95 | 16 | 100,000 |
| 201 | - | 94 | 15 | 98,000 |
| 197 | - | 93 | - | 95,000 |
| 192 | - | 92 | - | 93,000 |
| 187 | - | 91 | - | 90,000 |
| 183 | - | 90 | - | 89,000 |
| 179 | - | 89 | - | 87,000 |
| 174 | - | 88 | - | 85,000 |
| 170 | - | 87 | - | 83,000 |
| 167 | - | 86 | - | 81,000 |
| 163 | - | 85 | - | 79,000 |
| 156 | - | 83 | - | 76,000 |
| 149 | - | 81 | - | 73,000 |
| 143 | - | 79 | - | 71,000 |
| 137 | - | 76 | - | 67,000 |
| 131 | - | 74 | - | 65,000 |
| 126 | - | 72 | - | 63,000 |
| 121 | - | 70 | - | 60,000 |
| 116 | - | 68 | - | 58,000 |
| 111 | - | 66 | - | 56,000 |
What is the Relationship Between Tensile Strength and Hardness?
While they measure different properties, tensile strength and hardness are closely related.
- Hardness (like Rockwell, Brinell, or Vickers) measures a metal's resistance to localized indentation or scratching. Vickers (HV), for instance, is not in the main chart but is another common scale useful for very hard materials or thin sections. Hardness is a common, non-destructive test that is quick to perform.
- Tensile Strength (UTS) measures the maximum stress a material can withstand while being pulled or stretched before breaking
For many metals, including carbon steel and alloy steel, hardness is an excellent and cost-effective predictor of tensile strength. This relationship is the bridge between these two critical properties, allowing you to convert hardness to tensile strength without a destructive test.
As a quick approximation for steel, the most common Brinell hardness to tensile strength formula is:
- Tensile Strength (PSI) ≈ 500 x Brinell Hardness Number (HB)
This formula provides a reliable estimate, but you should always refer to a comprehensive chart based on ASTM standards for the most accurate data.
Applications for Steel, Aluminum, and Other Alloys
This conversion data is crucial for quality assurance, material selection, and weld procedure qualification. For instance, a chart converting carbon steel hardness to tensile strength is used to verify if a batch of material meets specified requirements.
While these conversions are most widely used for steel, the principles also apply to other materials. It's important to note that the correlation for aluminum may follow a different curve than for alloy steel.
Based on Industry Standards (ASTM & ISO)
The conversion values presented in the table above are derived from established industry standards. Documents like the ASTM E140 hardness conversion table and ASTM A370 provide the accepted data for correlating hardness values with tensile strength for various metallic materials. Following standards like ISO 18265 ensures you are using reliable, repeatable data for your projects.
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While these conversions are a powerful tool, selecting the right material is key. For all your alloy steel, carbon steel, and aluminum supply needs, or for expert services like water jet cutting and welding, contact the team at Warrenton Steel today.
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