When tightening a 36 bolt flange with an impact, what pattern should be used?

The star pattern is the correct approach when tightening a 36 bolt flange with an impact wrench. This method helps to ensure that the load is distributed evenly across the flange surface. By tightening the bolts in a star pattern, you minimize the risk of warping the flange or causing uneven stress, which can lead to leaks or failure in the joint.

This pattern involves starting at one bolt and progressing diagonally to the opposite bolt, then moving to another pair of diagonally opposite bolts. This sequence is repeated until all bolts are adequately tightened. It is especially important for situations where flanges are large or when they contain multiple bolts, as it promotes uniform compression of the gasket material between the flange faces, enhancing sealing integrity.

Using a clockwise or counterclockwise approach may lead to uneven tension across the flange, potentially compromising the seal. Similarly, a random sequence could introduce more complications by failing to ensure an even distribution of load, risking damage or failure during operation. Therefore, the star pattern is the recommended method for tightening bolts in flanged connections.