| Bolts grade, strength distinction and tightening |
| Strength to distinguish | 4.8 | 5.6 | 6.8 | 7.6 | 8.8 | 10.9 | 12.9 |
| Minimum breaking strength | 40kg/mm2 | 50kg/mm2 | 60kg/mm2 | 70kg/mm2 | 800kg/mm2 | 100kg/mm2 | 120kg/mm2 |
| The material | 45# | 35# | 40chromium | Alloy steel (hot) | Chromium-molybdenum alloy steel (hot) | Ni-cr-mo alloy steel (hot) | Ni-cr-mo alloy steel (hot) |
|
|
| （hot） | （hot） |
|
|
|
|
| Bolt | Nut Smm | kgm | kgm | Kgm | kgm | kgm | kgm | kgm |
| M8 | 12.5 | 2.4 | 2.9 | 3.43 | 3.77 | 9.8 | 6.34 | 7.89 |
| M10 | 15.4 | 3.43 | 4.16 | 4.9 | 5.39 | 6.86 | 9.06 | 11.27 |
| M12 | 17.3 | 4.9 | 5.95 | 7 | 7.7 | 4.8 | 12.95 | 16.1 |
| M14 | 22 | 7 | 8.5 | 10 | 11 | 14 | 18.5 | 23 |
| M16 | 24 | 10 | 12 | 14 | 17.5 | 21 | 28.5 | 36 |
| M18 | 27 | 14 | 17.5 | 21 | 25 | 29 | 39 | 49 |
| M20 | 30 | 18 | 23 | 28 | 34.5 | 41 | 55 | 69 |
| M22 | 32 | 23 | 28.5 | 34 | 44.5 | 55 | 74 | 93 |
| M24 | 36 | 32 | 40 | 48 | 59 | 70 | 95 | 120 |
| M27 | 41 | 45 | 55 | 65 | 85 | 105 | 142.5 | 180 |
| M30 | 46 | 60 | 75 | 90 | 105 | 120 | 180 | 240 |
| M36 | 55 | 100 | 125 | 150 | 165 | 180 | 240 | 300 |
| M42 | 65 | 155 | 197.5 | 240 | 260 | 280 | 375 | 470 |
| M48 | 75 | 230 | 197.5 | 350 | 375 | 400 | 540 | 680 |
| M52 | 80 | 280 | 350 | 420 | 450 | 480 | 665 | 850 |
| M56 | 85 | 360 | 495 | 530 | 570 | 610 | 830 | 1050 |
| M60 | 90 | 410 | 510 | 610 | 700 | 790 | 1070 | 1350 |
| M64 | 95 | 510 | 635 | 760 | 830 | 900 | 1170 | 1521 |
| M72 | 105 | 660 | 830 | 1000 | 1145 | 1290 |
|
|
| M76 | 110 | 750 | 925 | 1100 | 1300 | 1500 | 2045 |
|
| M80 | 115 | 830 | 1040 | 1250 | 1550 | 1850 |
|
|
| M90 | 130 | 1080 | 1365 | 1650 | 2075 | 2500 |
|
|
| M100 | 145 | 1400 | 1725 | 2050 |
|
|
|
|
| M110 | 155 | 1670 | 2110 | 2550 | 4980 |
|
|
|
| M120 | 175 | 2030 | 2540 | 3050 |
|
|
|
|
| M140 | 200 | 2700 | 3375 | 4050 |
|
|
|
|
| Note: The torque value in the table is the maximum torque value. It is recommended that the tightening torque value be the value in the table x 70-80% |
| Example: m48 bolt grade 8.8 table lookup 400× 80% = 320kgm |
| Nuts used are reduced by one grade. Example: grade 8.8 for bolts and nuts, grade 7.6 |
| The commonly used bolt strength is 8.8, for example, according to the 8.8 standard, when the bolt strength is 5.6, the value of 8.8 in the table is 0.47, when the bolt strength is 10.9, multiplied by 1.41, when the bolt strength is 12.9, the value should be multiplied by 1.69 (then the column 8.8 can be recorded). |
