Suggested Tightening Torques for Metric DIN 912 12.9 Socket Cap Screws
| Minimum Ulimate Tensile Loads-Metric Hex. Socket Head Cap Screws (ISO 898-1) | Suggested Seating Torque | |||
|---|---|---|---|---|
| Nominal Size | Stress Area(mm²) | Property Class 12.9 | Torque Value (Nm) | |
| Tensile Loads (N) | Self Colour | Zinc Plated | ||
| M1.6 | 1.27 | 1550 | 0.30 | 0.21 |
| M2 | 2.07 | 2530 | 0.60 | 0.43 |
| M2.5 | 2.48 | 4141 | 1.25 | 0.90 |
| M3 | 5.03 | 6140 | 2.20 | 1.50 |
| M4 | 8.78 | 10700 | 4.83 | 3.40 |
| M5 | 14.20 | 17300 | 10.00 | 6.90 |
| M6 | 20.10 | 24500 | 16.80 | 11.80 |
| M8 | 36.60 | 44600 | 41.00 | 29.00 |
| M10 | 58.00 | 70800 | 81.00 | 58.00 |
| M12 | 84.30 | 103000 | 142.00 | 100.00 |
| M14 | 115.00 | 140000 | 226.00 | 157.00 |
| M16 | 157.00 | 192000 | 350.00 | 242.00 |
| M18 | 192.00 | 234000 | 485.00 | 340.00 |
| M20 | 245.00 | 299000 | 685.00 | 480.00 |
| M22 | 303.00 | 370000 | 930.00 | 650.00 |
| M24 | 353.00 | 431000 | 1180.00 | 820.00 |
| M27 | 459.00 | 560000 | 1730.00 | 1235.00 |
| M30 | 561.00 | 684000 | 2380.00 | 1685.00 |
- Conversion factors: 1MPa=1N/mm2 ; 1kgf=9.8N ; 1MPa=145 p.s.i. approximately Thread height is approximately 0.6135p
- The self colour screw surface finish for self colour is "Black Oxide" after heat treatment.
- Metric thread: Grade 12.9 is 4g 6g thread class. Please refer to ISO 965 standard.
- The above specification is for coarse threads only.
- Suggested seating torque values, only apply to metric Grade 12.9 hex, socket head cap screws. The tightening torque will change, if fixing takes place with materials or surface finishes with variable fixing coefficient. The self colour table can only be applied to coefficient of friction in which the screw maintains it’s status, without any additional treatment after heat treatment and that the thread has anti-rustic oil protection.
- The data above should only be used as a reference guide. The proper torque can only be determined by analyzing the design parameters which include temperature plating, lubrication, face material, washer type and condition of the mating threads. Short term tensile creep and stress relaxation should be considered for applications where the temperature exceeds 400°F (204°C). Lower ductility, impact strength and fatigue life must be considered for screws subject to temperatures below -20°F (-29°C).
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