Bolt Preload and Tightening Torque Calculator

Torque method-based bolt connection design. Calculate required tightening torque based on bolt grade and design requirements.

Unit: mm
mm
mm
-
Recommended: 0.8-1.0
%
Typical: 10%-20%

Calculation Results

Tightening Torque MA (Target)
- Nm
Minimum Tightening Torque Mamin
- Nm
Maximum Tightening Torque Mamax
- Nm
Minimum Preload Force Fmmin
- KN
Maximum Preload Force FMmax
- KN

Important Notes

Calculation Principle

This calculator uses the torque method to calculate the tightening torque required to meet design requirements based on bolt property class, yield strength utilization, and torque dispersion. Suitable for forward design of bolt connections.

  • Yield Strength Utilization: Controls the ratio of bolt preload to yield strength
  • Torque Dispersion: Accounts for torque fluctuation during actual tightening

Usage Recommendations

  • For critical connections, use yield strength utilization of 0.8-0.9
  • Select torque dispersion based on tightening tool precision: manual tools 20%, power tools 15%, torque wrenches 10%
  • Results should include appropriate safety factors
  • Verify critical applications through testing