The table below shows standard hardness conversions for carbon and alloy steels, based on ASTM E140 / SAE J417. These values are approximate — actual conversions may vary depending on material composition and condition.
| HRC | HV (Vickers) | HRB | Tensile Strength (MPa) | Tensile Strength (ksi) |
|---|---|---|---|---|
| 68 | 940 | — | — | — |
| 67 | 900 | — | — | — |
| 66 | 865 | — | — | — |
| 65 | 832 | — | ~2500 | ~363 |
| 64 | 800 | — | ~2430 | ~352 |
| 63 | 772 | — | ~2360 | ~342 |
| 62 | 746 | — | ~2300 | ~334 |
| 61 | 720 | — | ~2240 | ~325 |
| 60 | 697 | — | 2172 | 315 |
| 59 | 674 | — | 2110 | 306 |
| 58 | 649 | — | 2048 | 297 |
| 57 | 633 | — | 1979 | 287 |
| 56 | 614 | — | 1924 | 279 |
| 55 | 595 | — | 1875 | 272 |
| 54 | 577 | — | 1820 | 264 |
| 53 | 560 | — | 1765 | 256 |
| 52 | 544 | — | 1713 | 248 |
| 51 | 528 | — | 1669 | 242 |
| 50 | 513 | — | 1620 | 235 |
| 49 | 498 | — | 1579 | 229 |
| 48 | 484 | — | 1531 | 222 |
| 47 | 471 | — | 1489 | 216 |
| 46 | 458 | — | 1455 | 211 |
| 45 | 446 | — | 1421 | 206 |
| 44 | 434 | — | 1386 | 201 |
| 43 | 421 | — | 1351 | 196 |
| 42 | 409 | — | 1317 | 191 |
| 41 | 400 | — | 1282 | 186 |
| 40 | 392 | — | 1248 | 181 |
| 39 | 382 | — | 1213 | 176 |
| 38 | 372 | — | 1179 | 171 |
| 37 | 363 | — | 1145 | 166 |
| 36 | 354 | — | 1124 | 163 |
| 35 | 345 | — | 1103 | 160 |
| 34 | 336 | — | 1076 | 156 |
| 33 | 327 | — | 1048 | 152 |
| 32 | 318 | — | 1020 | 148 |
| 31 | 310 | — | 1000 | 145 |
| 30 | 302 | — | 978 | 142 |
| 29 | 294 | — | 951 | 138 |
| 28 | 286 | — | 924 | 134 |
| 27 | 279 | — | 896 | 130 |
| 26 | 272 | — | 882 | 128 |
| 25 | 266 | ~100 | 868 | 126 |
| 24 | 260 | 99.5 | 841 | 122 |
| 23 | 254 | 99.0 | 814 | 118 |
| 22 | 248 | 98.5 | 793 | 115 |
| 21 | 238 | 98.0 | 772 | 112 |
| 20 | 228 | 97.5 | 758 | 110 |
Note: HRB values are only shown where the HRB scale is applicable (generally below HRC 25). Tensile strength values above HRC 60 are approximate extrapolations — direct tensile testing is recommended for ultra-hard steels.
Different steel strip applications require specific hardness ranges to balance cutting performance, wear resistance, and fatigue life. Below are typical hardness specifications for the grades we supply.
HRC 47 – 52 (HV 471 – 544)
Grade: 75Cr1
The tooth tips need hardness for edge retention while the blade body must flex millions of cycles around saw wheels without cracking.
HRC 44 – 52 (HV 434 – 544)
Grade: 75Ni8
The backing strip of bimetal band saw blades must resist fatigue cracking at the weld zone while maintaining enough spring-back to track straight on wheels.
HRC 55 – 62 (HV 595 – 746)
Grade: SK85
High carbon steel hardened for maximum edge retention in cutting paper, film, textiles, and food products. Typically quenched and tempered to customer specification.
HRC 28 – 55 (HV 286 – 595)
Grade: 42CrMo4
Chrome-molybdenum alloy steel with excellent fatigue life. Hardness is adjusted by tempering temperature to balance strength and ductility for the specific application.
The most widely used scale for hardened steel. A diamond cone (Brale) indenter is pressed into the surface with 150 kgf total load. The depth of penetration is measured and converted to a hardness number. HRC is fast, non-destructive (small indent), and reliable from HRC 20 to HRC 68. Below HRC 20, switch to HRB. Above HRC 68, the diamond indenter may be damaged.
Uses a diamond pyramid indenter with variable load (typically 1–50 kgf). The diagonal of the square indent is measured under a microscope. HV covers the full hardness range from soft annealed metals to the hardest ceramics. It is more precise than Rockwell but slower, and is preferred for thin materials, case-hardened layers, and research applications.
Uses a 1/16-inch steel ball indenter with 100 kgf load. Designed for softer materials: annealed steel, brass, copper, and aluminum alloys. Valid range is HRB 20 to 100. When material hardness exceeds HRB 100, the ball indenter deforms — switch to HRC for accurate measurement.
Tensile strength (UTS) is the maximum stress a material can withstand before fracture. While hardness and tensile strength are different properties, they correlate well for carbon and alloy steels. The conversion values in ASTM E140 are empirically derived and should be treated as approximations. For critical applications, always perform direct tensile testing.
HRC (Rockwell C) measures depth of penetration using a diamond cone at 150 kgf. HV (Vickers) measures indent area using a diamond pyramid at variable load. HRC is faster and standard for shop-floor testing of hardened steel (20-68 HRC). HV covers a wider range and is more precise, making it preferred for thin sections, coatings, and laboratory work. The two scales are not linearly related — conversion requires ASTM E140 standard lookup tables with interpolation.
HRC to tensile strength conversion is based on empirical data compiled in ASTM E140 (originally derived from SAE J417). For example, HRC 40 corresponds to approximately 1248 MPa (181 ksi), and HRC 50 to approximately 1620 MPa (235 ksi). These approximate conversions apply only to carbon and alloy steels. Stainless steels, tool steels, and non-ferrous metals may show significantly different relationships between hardness and tensile strength.
Use HRB (Rockwell B) for softer metals: annealed steel, unhardened steel strip, copper alloys, and aluminum. The HRB scale uses a steel ball indenter with 100 kgf load and is valid from HRB 20 to 100. Once material hardness exceeds approximately HRB 100 (roughly equivalent to HRC 20), switch to the HRC scale. Testing a hard material on the HRB scale will damage the ball indenter and give inaccurate readings.
Factory-direct strip in 13 steel grades. Heat treated to your exact hardness specification, verified by calibrated testing.