Effect of Tightening Speed on Clamp Load Distribution in Gasketed Joints

An experimental study is presented in order to determine the effect of tightening speed on clamp load distribution in a gasketed steel joint. Two gasket materials are considered, namely, Styrene Butadiene Rubber and Flexible Graphite. Flange tightening is achieved using a multiple spindle fastening system that has speed and torque controls; the fastening system is also capable of performing simultaneous tightening of all fasteners using other advanced control modes such as torque-turn or torque-to-yield strategies. Two tightening patterns are investigated, namely, simultaneous tightening of all bolts and individual tightening of one bolt at a time following a star pattern. The tightening speed in this study ranges from 1 rpm to 100 rpm. Clamp load loss due to the combined effects of gasket creep relaxation and elastic interaction is investigated. Additionally, data is presented to show the effect of using a two-pass tightening method on the residual value of the clamp load in gasketed joints.