Bolt Torquing Theory

Advantages of using accurate torque or utilizing correct tightening methods

  • Bolt loading Uniformity
    • Your gasketed joints has to have an even and consistent compression via accurate bolt loads for the gasket to be effective. Refer to ASME B16.5 or contact a Petracarbon representative.
  • Increased Safety through effective recognition of unsafe methods of torquing
    • Elimates dangerous activities of manual uncontrolled tightening such as “flogging” and ensures the requirement that the torque operators be skilled and follow procedures.
  • Do it right the first time
    • By ensuring the correct assembly and tightening of the joint are carried out the first time, many of the uncertainties surrounding in-service joint failures are removed.
  • Effectively calculated, precise and accurate bolt loads
    • Petracarbon uses tools with controllable outputs and specifically adopts calculation to determine the required tool settings.
  • Increased productivity
    • By using hydraulic torque, traditional methods of tightening using increased manpower is eliminated. Also reduces tightening time and operator fatigue by replacing manual effort with the use of controlled tooling.
  • Repeatable and Reliable results
    • Using calibrated, tested equipment, following procedures and employing skilled operators achieves known results consistently.

Lubrication Reduces Friction

Lubrication reduces the friction during tightening, decreases bolt failure during installation and increases bolt service life. Variation in friction coefficients affect the amount of preload achieved at a specified torque. Higher friction results in less conversion of torque to preload. The value for the friction coefficient provided by the lubricant manufacturer must be known to accurately establish the required torque value.

Lubricant or anti-seizure compounds should be applied to both the nut bearing surface and the male threads.