1. Torque Reference Range
M10 screws: The recommended torque for general installation is 35-55 Nm, and can be increased to 60-80 Nm for anti-loosening requirements.
12.9 grade high-strength screws: The torque for M10 screws can reach 45-75 Nm, depending on the material and lubrication conditions.
General Standard: The typical torque for 8.8 grade carbon steel screws (e.g., M6 is 10-12 Nm, M8 is 20-25 Nm) is 20%-30% higher for 12.9 grade screws.
2. Influencing Factors
Material: Stainless steel requires increased torque due to its high coefficient of friction, while softer materials such as aluminum alloy should have lower torque.
Lubrication: When applying grease or thread sealant, reduce torque by 15%-25%. Ambient Temperature: In high-temperature environments (such as engines), tighten in stages. Pre-tighten to 80% cold, then re-tighten as the temperature rises.
3. Operation Recommendations
Tool Selection: Prefer a torque wrench or power tool (with preset torque values). Do not use extension rods to avoid exceeding the torque limit.
Verification Method: Mark the alignment line or re-test with a torque tester. Re-tighten key areas after 24 hours.
4. Special Scenarios
Vibration Environments: Install spring washers or threadlockers, but recalibrate the torque.
Old Screws: Check thread integrity. Replace worn holes. If rust is present, soak with rust remover instead of hammering.
5. Torque Calculation Principles
5-4-1 Principle: 10% of the tightening torque is used for preload, 40% to overcome thread friction, and 50% to overcome bearing surface friction. Quick table lookup method: Based on the bolt grade and friction coefficient (e.g. M12-10.9, a friction coefficient of 0.12 corresponds to 123 Nm).
