Abstract
In the use of the impact wrenches, since the value of tightening coefficient is bigger, it is necessary to take account the value of tightening coefficient when bolts and nuts in important bolted joints are tightened. In the present study, tightening method of nuts and bolts in bolted pipe flange joints is examined when impact wrench is used from FEM calculations and experiments. In this study, with an electric impact wrench, we performed the tightening experiment of the comparatively small size pipe flange. And the tightening experiment which managed tightening time correctly was made using electronic time-controlled system. As a result, the scatter of axial bolt tension tightened by electric impact wrench with electronic time-controlled system is the same as that tightened by hand torque wrench.
