B K Steel CompanyB K Steel Company| Heat TreatedCondition | Q | R | S | T | U | V | W | X | Z |
|---|---|---|---|---|---|---|---|---|---|
| Tensile Strength | 625-775 n/mm2 |
700-850 n/mm2 |
775-925 n/mm2 |
850-1000 n/mm2 |
925-1075 n/mm2 |
1000-1150 n/mm2 |
1075-1225 n/mm2 |
1150-1300 n/mm2 |
1550 n/mm2 |
| Hardness Brinell | 179-229 | 201-225 | 223-277 | 248-302 | 269-331 | 293-352 | 311-375 | 345-401 | 444 |
This table shows approximate hardness of steel using Brinell, Rockwell B and C and Vickers scales. These conversion charts are provided for guidance only as each scales uses different methods of measuring hardness. The right hand column show an approximate equivalent tensile strength.
Reference Table: Steel hardness conversion chart - all values approximate. | ||||
|---|---|---|---|---|
| Brinell Hardness HB | Rockwell HRC | Rockwell HRB | Vickers HV | N/mm² |
| 800 | 72 | |||
| 780 | 71 | |||
| 760 | 70 | |||
| 752 | 69 | |||
| 745 | 68 | |||
| 746 | 67 | |||
| 735 | 66 | |||
| 711 | 65 | |||
| 695 | 64 | |||
| 681 | 63 | |||
| 658 | 62 | |||
| 642 | 61 | |||
| 627 | 60 | |||
| 613 | 59 | |||
| 601 | 58 | 746 | ||
| 592 | 57 | 727 | ||
| 572 | 56 | 694 | ||
| 552 | 55 | 649 | ||
| 534 | 54 | 120 | 589 | |
| 513 | 53 | 119 | 567 | |
| 504 | 52 | 118 | 549 | |
| 486 | 51 | 118 | 531 | |
| 469 | 50 | 117 | 505 | |
| 468 | 49 | 117 | 497 | |
| 456 | 48 | 116 | 490 | 1569 |
| 445 | 47 | 115 | 474 | 1520 |
| 430 | 46 | 115 | 458 | 1471 |
| 419 | 45 | 114 | 448 | 1447 |
| 415 | 44 | 114 | 438 | 1422 |
| 402 | 43 | 114 | 424 | 1390 |
| 388 | 42 | 113 | 406 | 1363 |
| 375 | 41 | 112 | 393 | 1314 |
| 373 | 40 | 111 | 388 | 1265 |
| 360 | 39 | 111 | 376 | 1236 |
| 348 | 38 | 110 | 361 | 1187 |
| 341 | 37 | 109 | 351 | 1157 |
| 331 | 36 | 109 | 342 | 1118 |
| 322 | 35 | 108 | 332 | 1089 |
| 314 | 34 | 108 | 320 | 1049 |
| 308 | 33 | 107 | 311 | 1035 |
| 300 | 32 | 107 | 303 | 1020 |
| 290 | 31 | 106 | 292 | 990 |
| 277 | 30 | 105 | 285 | 971 |
| 271 | 29 | 104 | 277 | 941 |
| 264 | 28 | 103 | 271 | 892 |
| 262 | 27 | 103 | 262 | 880 |
| 255 | 26 | 102 | 258 | 870 |
| 250 | 25 | 101 | 255 | 853 |
| 245 | 24 | 100 | 252 | 838 |
| 240 | 23 | 100 | 247 | 824 |
| 233 | 22 | 99 | 241 | 794 |
| 229 | 21 | 98 | 235 | 775 |
| 223 | 20 | 97 | 227 | 755 |
| 216 | 19 | 96 | 222 | 716 |
| 212 | 18 | 95 | 218 | 706 |
| 208 | 17 | 95 | 210 | 696 |
| 203 | 16 | 94 | 201 | 680 |
| 199 | 15 | 93 | 199 | 667 |
| 191 | 14 | 92 | 197 | 657 |
| 190 | 13 | 92 | 186 | 648 |
| 186 | 12 | 91 | 184 | 637 |
| 183 | 11 | 90 | 183 | 617 |
| 180 | 10 | 89 | 180 | 608 |
| 175 | 9 | 88 | 178 | 685 |
| 170 | 7 | 87 | 175 | 559 |
| 167 | 6 | 86 | 172 | 555 |
| 166 | 5 | 86 | 168 | 549 |
| 163 | 4 | 85 | 162 | 539 |
| 160 | 3 | 84 | 160 | 535 |
| 156 | 2 | 83 | 158 | 530 |
| 154 | 1 | 82 | 152 | 515 |
| 149 | 81 | 149 | 500 | |
| 147 | 80 | 147 | 490 | |
| 143 | 79 | 146 | 482 | |
| 141 | 78 | 144 | 481 | |
| 139 | 77 | 142 | 480 | |
| 137 | 76 | 140 | 475 | |
| 135 | 75 | 137 | 467 | |
| 131 | 74 | 134 | 461 | |
| 127 | 72 | 129 | 451 | |
| 121 | 70 | 127 | 431 | |
| 116 | 68 | 124 | 422 | |
| 114 | 67 | 121 | 412 | |
| 111 | 66 | 118 | 402 | |
| 107 | 64 | 115 | 382 | |
| 105 | 62 | 112 | 378 | |
| 103 | 61 | 108 | 373 | |
| 95 | 56 | 104 | ||
| 90 | 52 | 95 | ||
| 81 | 41 | 85 | ||
| 76 | 37 | 80 | ||
| Brinell HB | Rockwell HRC | Rockwell HRB | Vickers HV | N/mm² |
| 3000kg 10mm Ball | 150kg Brale | 100kg 1/16" Ball | Diamond Pyramid 120kg | Tensile strength (Approx) |
Reference table: Steel Hardness conversion chart Since the various types of hardness tests do not all measure the same combination of material properties, conversion from one hardness scale to another is only an approximate process. Because of the wide range of variation among different materials, it is not possible to state confidence limits for the errors in using a conversion chart. |
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