In the testing industry, it is a common process to convert one hardness scale to another. For this purpose, many Standards of international level such as ASTM E140, ISO 18265 have converted scales. But with these tables it is concluded that because of different hardness test methods defining a single conversion method is not possible, That’s why these standards formulate tables for conversion process, with test load and hardness ranges. Therefore, there are a number of tables which should be consulted while doing the process. It is necessary you choose the right values form these tables. These tables or conversion charts are as follows.
I. Scale – Symbol – Indenter and Load Force
In conversion scales, common terms which should be first understood are scales, symbol, indenter and load or test force. All of these tables are based on these terms. For any hardness test, these tables are used for conversion of values from one test to another to get accurate results.
Scale | Symbol | Indenter | Load force | |
Vicker | HV | diamond, nickel alloys | 1,5,10,30 kgf | |
copper | 100kgf | |||
aluminum | 15kgf | |||
Knoop | HK | diamond | 500gf + | |
Rockwell | A | HRA | diamond | 60kgf |
B | HRB | Steel ball 1/16” | 100kgf | |
C | HRC | diamond | 150kgf | |
D | HRD | diamond | 100kgf | |
E | HRE | Steel ball 1/8” | 100kgf | |
F | HRF | Steel ball 1/16” | 60kgf | |
G | HRG | Steel ball 1/16” | 150kgf | |
H | HRH | Steel ball 1/8” | 60kgf | |
K | HRK | Steel ball 1/8” | 150kgf | |
Superficial Rockwell | 15N | HR15N | Diamond | 15kgf |
30N | HR30N | Diamond | 30kgf | |
45N | HR45N | Diamond | 45kgf | |
15T | HR15T | Steel ball 1/16” | 15kgf | |
30T | HR30T | Steel ball 1/16” | 30kgf | |
45T | HR45T | Steel ball 1/16” | 45kgf | |
15W | HR15W | Steel ball 1/8” | 15kgf | |
Brinell | HBW | Tungsten Carbide 10mm ball | 3000kgf | |
HBS | Steel 10mm, steel nickel Brass and Aluminum | 3000kgf 500kgf | ||
II. Rockwell C Hardness Range
Hardness Conversion Chart for Non-Austenitic Steels (Rockwell C Hardness Range)
| Brinell Hardness Number | Rockwell | Superficial Rockwell Number | |||||||
Rockwell C 150kgf(HRC) | Vickers (HV) | Standard (HBS) | Carbide (HBW) | Knoop (HK) | Scale | Sclero scope | ||||
A (HRA) | D (HRD) | 15-N (HR15N) | 30-N (HR30N) | 45-N (HR45N) | ||||||
10mm 3000kgf | 10mm 3000kgf | 500kgf + more | 60kgf
| 100kgf
| 15kgf
| 30kgf
| 45kgf
|
| ||
68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 | 940 900 865 832 800 772 746 720 697 674 653 633 613 595 577 560 544 528 513 498 484 471 458 446 434 423 412 402 392 382 372 363 354 345 336 327 318 310 302 294 286 279 272 266 260 254 248 243 238 | … … … … … … … … … … … … … … … … (500) (487) (475) (464) 451 442 432 421 409 400 390 381 371 362 353 344 336 327 319 311 301 294 286 279 271 264 258 253 247 243 237 231 226 | … … … (739) (722) (705) (688) (670) (654) 634 615 595 577 560 543 525 512 496 481 469 455 443 432 421 409 400 390 381 371 362 353 344 336 327 319 311 301 294 286 279 271 264 258 253 247 243 237 231 226 | 920 895 870 846 822 799 776 754 732 710 690 670 650 630 612 594 576 558 542 526 510 495 480 466 452 438 426 414 402 391 380 370 360 351 342 334 326 318 311 304 297 290 284 278 272 266 261 256 251 | 85.6 85.0 84.5 83.9 83.4 82.8 82.3 81.8 81.2 80.7 80.1 79.6 79.0 78.5 78.0 77.4 76.8 76.3 75.9 75.2 74.7 74.1 73.6 73.1 72.5 72.0 71.5 70.9 70.4 69.9 69.4 68.9 68.4 67.9 67.4 66.8 66.3 65.8 65.3 64.8 64.3 63.8 63.3 62.8 62.4 62.0 61.5 61.0 60.5 | 76.9 76.1 75.4 74.5 73.8 73.0 72.2 71.5 70.7 69.9 69.2 68.5 67.7 66.9 66.1 65.4 64.6 63.8 63.1 62.1 61.4 60.8 60.0 59.2 58.5 57.7 56.9 56.2 55.4 54.6 53.8 53.1 52.3 51.5 50.8 50.0 49.2 48.4 47.7 47.0 46.1 45.2 44.6 43.8 43.1 42.1 41.6 40.9 40.1 | 93.2 92.9 92.5 92.2 91.8 91.4 91.1 90.7 90.2 89.8 89.3 88.9 88.3 87.9 87.4 86.9 86.4 85.9 85.5 85.0 84.5 83.9 83.5 83.0 82.5 82.0 81.5 80.9 80.4 79.9 79.4 78.8 78.3 77.7 77.2 76.6 76.1 75.6 75.0 74.5 73.9 73.3 72.8 72.2 71.6 71.0 70.5 69.9 69.4 | 84.4 83.6 82.8 81.9 81.1 80.1 79.3 78.4 77.5 76.6 75.7 74.8 73.9 73.0 72.0 71.2 70.2 69.4 68.5 67.6 66.7 65.8 64.8 64.0 63.1 62.2 61.3 60.4 59.5 58.6 57.7 56.8 55.9 55.0 54.2 53.3 52.1 51.3 50.4 49.5 48.6 47.7 46.8 45.9 45.0 44.0 43.2 42.3 41.5 | 75.4 74.2 73.3 72.0 71.0 69.9 68.8 67.7 66.6 65.5 64.3 63.2 62.0 60.9 59.8 58.6 57.4 56.1 55.0 53.8 52.5 51.4 50.3 49.0 47.8 46.7 45.5 44.3 43.1 41.9 40.8 39.6 38.4 37.2 36.1 34.9 33.7 32.5 31.3 30.1 28.9 27.8 26.7 25.5 24.3 23.1 22.0 20.7 19.6 | 97.3 95.0 92.7 90.6 88.5 86.5 84.5 82.6 80.8 79.0 77.3 75.6 74.0 72.4 70.9 69.4 67.9 66.5 65.1 63.7 62.4 61.1 59.8 58.5 57.3 56.1 54.9 53.7 52.6 51.5 50.4 49.3 48.2 47.1 46.1 45.1 44.1 43.1 42.2 41.3 40.4 39.5 38.7 37.8 37.0 36.3 35.5 34.8 34.2 |
III. Rockwell B Hardness Range
Hardness Conversion Chart for Non-Austenitic Steels (Rockwell B Hardness Range)
| Rockwell | Superficial Rockwell Number | ||||||
Rockwell B 100kgf (HRB) | Vickers (HV) | (HBS) 10mm Standard ball 3000kgf | Knoop 500-gf + (HK) | A Scale 60 kgf (HRA) | F Scale 60kgf (HRF) | 15-T Scale 15-kgf (HR15T) | 30-T Scale 30-kgf (HR30T) | 45-T Scale 45-kgf (HR45T) |
100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 … … … … … … … … … … … … … … … … … … … … … … … … … | 240 234 228 222 216 210 205 200 195 190 185 180 176 172 169 165 162 159 156 153 150 147 144 141 139 137 135 132 130 127 125 123 121 119 117 116 114 112 110 108 107 106 104 103 101 100 … … … … … … … … … … … … … … … … … … … … … … … … … | 240 234 228 222 216 210 205 200 195 190 185 180 176 172 169 165 162 159 156 153 150 147 144 141 139 137 135 132 130 127 125 123 121 119 117 116 114 112 110 108 107 106 104 103 101 100 … … … … … … … … … … … … … … … … … … … … … … … … … | 251 246 241 236 231 226 221 216 211 206 201 196 192 188 184 180 176 173 170 167 164 161 158 155 152 150 147 145 143 141 139 137 135 131 129 127 125 124 122 120 118 117 115 114 112 111 110 109 108 107 106 105 104 103 102 101 100 99 98 97 96 95 94 93 92 91 90 89 88 87 | 61.5 60.9 60.2 59.5 58.9 58.3 57.6 57.0 56.4 55.8 55.2 54.6 54.0 53.4 52.8 52.3 51.7 51.1 50.6 50.0 49.5 48.9 48.4 47.9 47.3 46.8 46.3 45.8 45.3 44.8 44.3 43.8 43.3 42.8 42.3 41.8 40.9 40.4 40.0 39.5 39.0 38.6 38.1 37.7 37.2 36.8 36.3 35.9 35.5 35.0 34.6 34.1 33.7 33.3 32.9 32.4 32.0 31.6 31.2 30.7 30.3 29.9 29.5 29.1 28.7 28.2 27.8 27.4 27.0 26.6 | … … … … … … … … … … … … … … … … … … … … … … … … … 99.6 99.1 98.51 98.0 97.4 96.8 96.2 95.6 95.1 94.5 93.9 93.4 92.8 92.2 91.7 91.1 90.5 90.0 89.4 88.8 88.2 87.7 87.1 86.5 86.0 85.4 84.8 84.3 83.7 83.1 82.6 82.0 81.4 80.8 80.3 79.7 79.1 78.6 78.0 77.4 76.9 76.3 75.7 75.2 74.6 74.0 | 93.1 92.8 92.5 92.1 91.8 91.5 91.2 90.8 90.5 90.2 89.9 89.5 89.2 88.9 88.6 88.2 87.9 87.6 87.3 86.9 86.6 86.3 86.0 85.6 85.3 85.0 84.7 84.3 84.0 83.7 83.4 83.0 82.7 82.4 82.1 81.8 81.4 81.1 80.8 80.5 80.1 79.8 79.5 79.2 78.8 78.5 78.2 77.9 77.5 77.2 76.98 76.6 76.2 75.9 75.6 75.3 74.9 74.6 74.3 74.0 73.6 73.3 73.0 72.7 72.3 72.0 71.7 71.4 71.0 70.7 70.4 | 83.1 82.5 81.8 81.1 80.4 79.8 79.1 78.4 77.8 77.1 76.4 75.8 75.1 74.4 73.8 73.1 72.4 71.8 71.1 70.4 69.7 69.1 68.4 67.7 67.1 66.4 65.7 65.1 64.4 63.7 63.1 62.4 61.7 61.0 60.4 59.7 59.0 58.4 57.7 57.0 56.4 55.7 55.0 54.4 53.7 53.0 52.4 51.7 51.0 50.3 49.7 49.0 48.3 47.7 47.0 46.3 45.7 45.0 44.3 43.7 43.0 42.3 41.6 41.0 40.3 39.6 39.0 38.3 37.6 37.0 36.3 | 72.9 71.9 70.9 69.9 68.9 67.9 66.9 65.9 64.8 63.8 62.8 61.8 60.8 59.8 58.8 57.8 56.8 55.8 54.8 53.8 52.8 51.8 50.8 49.8 48.8 47.8 46.8 45.8 44.8 43.8 42.8 41.8 40.8 39.8 38.7 37.7 36.7 35.7 34.7 33.7 32.7 31.7 30.7 29.7 28.7 27.7 26.7 25.7 24.7 23.7 22.7 21.7 20.7 19.7 18.7 17.7 16.7 15.7 14.7 13.6 12.6 11.6 10.6 9.6 8.6 7.6 6.6 5.6 4.6 3.6 2.6 |
IV. Leeb (Type D) Hardness Range
Leeb (Type D) Hardness Conversion for Non-Austenitic Steels(Rockwell C Hardness Range)
Leeb Hardness, Type D Impact Device (HDL) | Rockwell C Hardness 150kgf (HRC) | Vickers Hardness (HV 10) | Brinell Hardness 10mm Steel Ball 3000kgf (HBS) |
828 819 809 800 791 782 773 764 755 746 737 729 720 712 703 695 687 679 671 663 655 647 640 632 625 618 611 603 596 590 583 576 570 563 557 551 545 539 533 527 521 516 510 | 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 | 762 737 711 688 667 645 625 605 586 568 550 534 517 503 487 473 460 447 434 422 410 398 388 377 368 358 349 339 330 323 314 306 299 291 284 277 271 264 258 251 245 240 234 | (721) (699) (675) (654) 634 614 595 577 559 542 526 511 496 482 467 455 442 430 418 407 395 385 375 365 356 347 338 328 320 313 305 297 291 283 276 270 264 258 252 246 240 235 229 |
V. Cylindrical Correction Chart
Scales C, D, A
Scales C, D, A Brale Diamond Indenter Diamater of Specimen- inches (mm) | |||||||||
Hardness Reading | ¼” 6.4mm | 3/8” 10mm | ½” 13mm | 5/8” 16mm | ¾” 19mm | 7/8” 22mm | 1” 25mm | 1-1/4” 32mm | 1-1/2” 38mm |
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 | 6.0 5.5 5.0 4.0 3.5 3.0 2.5 2.0 1.5 1.5 1.0 1.0 0.5 0.5 0.5 | 4.5 4.0 3.5 3.0 2.5 2.0 2.0 1.5 1.0 1.0 1.0 0.5 0.5 0.5 0 | 3.5 3.0 2.5 2.0 2.0 1.5 1.5 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0 | 2.5 2.5 2.0 1.5 1.5 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0.5 0 0 | 2.0 2.0 1.5 1.5 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0 0 | 1.5 1.5 1.5 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0 0 0 | 1.5 1.0 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0 0 0 0 | 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0.5 0 0 0 0 0 0 0 | 1.0 1.0 0.5 0.5 0.5 0.5 0.5 0 0 0 0 0 0 0 0 |
Scales B, F, G
Scales B, F, G 1/16” Ball Indenter Diamater of Specimen- inches (mm) | |||||||||
Hardness Reading | ¼” 6.4mm | 3/8” 10mm | ½” 13mm | 5/8” 16mm | ¾” 19mm | 7/8” 22mm | 1” 25mm | ||
0 10 20 30 40 50 60 70 80 90 100 | 12.5 12.0 11.0 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.5 | 8.5 8.0 7.5 6.5 6.0 5.5 5.0 4.0 3.5 3.0 2.5 | 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 | 5.5 5.0 4.5 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.5 | 4.5 4.0 4.0 3.5 3.0 3.0 2.5 2.0 1.5 1.5 1.0 | 3.5 3.5 3.5 3.0 2.5 2.5 2.0 2.0 1.5 1.5 1.0 | 3.0 3.0 3.0 2.5 2.5 2.0 2.0 1.5 1.5 1.0 0.5 | ||
VI. Minimum Thickness Chart
Minimum Thickness Inch | Minimum Thickness mm | Rockwell | Superficial Rockwell | Rockwell | |||||||||
C | D | C | 15N | 30N | 45N | 15T | 30T | 45T | F | B | G | ||
0.006 0.008 0.010 0.012 0.014 0.016 0.018 0.020 0.022 0.024 0.026 0.028 0.030 0.032 0.034 0.036 0.038 0.040 | 0.15 0.20 0.25 0.30 0.36 0.41 0.46 0.51 0.56 0.61 0.66 0.71 0.76 0.81 0.86 0.91 0.96 1.02 | … … … … … … 9 0 69 67 65 62 57 52 45 37 28 20 | … … … … … 0 77 75 72 68 63 58 51 43 + + + | … … … … … 86 84 82 79 76 71 67 60 + + + + + | 92 90 88 83 76 68 + + + + + + + + + + + + | … … … 82 78.5 74 66 57 47 + + + + + + + + + | … … … 77 74 72 68 63 58 51 37 20 + + + + + + | … … 91 86 81 75 68 + + + + + + + + + + + | … … … … 80 72 64 55 45 34 + + + + + + + + | … … … … … 71 62 53 43 31 18 4 + + + + + + | … … … … … … … … … 98 91 85 77 69 + + + + | … … … … … … … … … 94 87 80 71 62 52 40 28 + | … … … … … … … … … 94 87 76 68 59 50 42 31 22 |
“+”: can’t be test, no minimum hardness
VII. Weight – Load – Indentor
Scale | Indentor Type | Preliminary Force N (kgf) | Total Force N(kgf) | Typical Applications |
A | Spheroconical Diamond | 98.07 (10) | 588.4 (60) | Cemented carbides, thin steel, and shallow case hardened steel |
B | 1/16” Carbide Ball | 98.07 (10) | 980.7(100) | Copper alloys, soft steels, aluminum alloys, malleable iron, etc. |
C | Spheroconical Diamond | 98.07 (10) | 1471 (150) | Steel, hard cast irons, pearlitic malleable iron, titanium, other harder than HRB 100 |
D | Spheroconical Diamond | 98.07 (10) | 980.7(100) | Thin steel and medium case hardened steel, and pearlitic malleable iron |
E | 1/8” Carbide | 98.07 (10) | 980.7(100) | Cast Iron, Aluminum,magnesium, bearing metals |
F | 1/16”Carbide | 98.07 (10) | 588.4 (60) | Annealed copper alloys and thin soft sheet metals |
G | 1/16” Carbide | 98.07 (10) | 1471(150) | Malleable irons, copper-nickel-zinc and cupro-nickel alloys |
H | 1/8” Carbide | 98.07 (10) | 588.4 (60) | Aluminum, zinc and lead |
K | 1/8” Carbide | 98.07 (10) | 1471(150) | Bearing Metals and other very soft or thin materials. Use smallest ball and heaviest load that doesn’t give anvil effect |
L | ¼” Carbide | 98.07 (10) | 588.4 (60) | |
M | ¼” Carbide | 98.07 (10) | 980.7(100 | |
P | ¼” Carbide | 98.07 (10) | 1471(150) | |
R | ½” Carbide | 98.07 (10) | 588.4 (60) | |
S | ½” Carbide | 98.07 (10) | 980.7(100 | |
V | ½” Carbide | 98.07 (10) | 1471(150) | |
15N | Spheroconical Diamond | 29.42 (3) | 147.1 (15) | Similar to A, C and D scales but for thinner gage material. |
30N | Spheroconical Diamond | 29.42 (3) | 294.2 (30) | |
45N | Spheroconical Diamond | 29.42 (3) | 441.3 (45) | |
15T | 1/16”Carbide | 29.42 (3) | 147.1 (15) | Similar to B, F and G scales but for thinner gage material. |
30T | 1/16” Carbide | 29.42 (3) | 294.2 (30) | |
45T | 1/16” Carbide | 29.42 (3) | 441.3 (45) | |
15W | 1/8” Carbide | 29.42 (3) | 147.1 (15) | Very Soft Material |
30W | 1/8” Carbide | 29.42 (3) | 294.2 (30) | |
45W | 1/8” Carbide | 29.42 (3) | 441.3 (45) | |
15X | 1/4” Carbide | 29.42 (3) | 147.1 (15) | |
30X | 1/4” Carbide | 29.42 (3) | 294.2 (30) | |
45X | 1/4” Carbide | 29.42 (3) | 441.3 (45) | |
15Y | 1/2” Carbide | 29.42 (3) | 147.1 (15) | |
30Y | 1/2” Carbide | 29.42 (3) | 294.2 (30) | |
45Y | 1/2” Carbide | 29.42 (3) | 441.3 (45) |
Conclusion
Hardness testing methods are used to analyze the strength of the material, which is going to be used in the manufacturing of machines, automobiles etc. Knowing about the hardness tests only is not sufficient, how to accurately process it? How to process it? And how to convert the values for your required process is also necessary. In this article, all types of conversion tables for hardness testing are present. To learn more about hardness testing methods and their process, visit our website to get your required information.