Stress Variation in the Flange of a Gasketed Flanged Pipe Joint During Bolt up and Operating Conditions

This paper presents results of an experimental study of the behavior of the stress variation at the flange and attached pipe section of a gasketed flanged pipe joint during both the bolt up (pre-loading) procedure and under operating (internal pressure loading) conditions. Stress variations showing flange yielding, flange rotation, effects of a joint tightening sequence, identification of the mode of response to loading (static or dynamic) and the effects of retightening are discussed in detail. Additionally, the importance of high quality bolting with proper surface treatment and the use of proper tooling to reduce the magnitude of overall flange stress variation are also discussed.