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Bolt Tightening Sequence Procedures

It might seem like common sense, but taking the extra time to make sure you’ve performed the correct bolt tightening sequence can make a massive difference in an application.

In this blog post, we’ll review the basics of bolt tightening procedure.

Flanged connections only work when every component is correct. A leading cause of leaky gasket joints is improper installation. Before you begin bolting, take the following steps:

  • Clean the flange faces and check for defects such as burrs and dents
  • Give all bolts and nuts a visual inspection, looking for corroded or damaged threads. Replace whenever necessary.
  • Lubricate the nuts and bolts, which reduces friction during the tightening sequence. This in turn decreases the chances of bolt failure during installation and strengthens the life of the bolt.

From there, hand tighten until they are snug against the flange. And always make sure you’ve used the correct sequence in your bolt tightening procedure:

For four and eight-bolt flanges:

  • 1st round – 30 percent of final torque
  • 2nd round – 60 percent of final torque
  • 3rd round – 100 percent of final torque
  • Final round – clockwise or counter-clockwise around the flange

For flanges with 12 or more bolts:

  • 1st round – 20 percent of final torque
  • 2nd round – 40 percent of final torque
  • 3rd round – 80 percent of final torque
  • 4th round – 100 percent of final torque
  • Final round – clockwise or counter-clockwise around the flange

PLEASE TAKE NOTE: The above bolt tightening sequences are “the most common” but you should always confirm the exact torque patterns for your equipment with your site engineering team.

Are you worried you don’t have the right tools for your bolt tightening procedure? Maxpro can help.

Maxpro is an a2la accredited calibration lab.We’ve spent close to 25 years providing quality torque tools to clients in critical industries such as construction, power generation and the military.

Beyond that, we’re also available to make sure those tools are calibrated properly, with the help of our A2LA-accredited calibration lab.

Maxpro adheres to ISO/IEC 17025 standards.We also make sure that every torque tool that we rent or sell adheres to ISO/IEC 17025 standards, thus ensuring that our clients can tighten bolts with confidence. Contact Maxpro today to learn how we can help you achieve the highest possible standards on your next project.

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