Test study on high strength high-neck forging flange of UHV steel tube transmission towers

Application of high-neck flange of steel tube tower in China and other countries is investigated. Based on the theoretical and experimental research of China Electric Power Research Institute (CEPRI) about high-neck flange with strength of Q345, which corresponds to Chinese criterion, axial tension tests about Q420 and Q460 high-neck forging flanges are carried through. It is suggested that the side of small diameter tube of butt welding flange should be strengthened in design. It is also found that steel tube near the butt weld, straight neck of flange and bolts are all under eccentrically bearing states. Bearing capacities of Q460 high-neck butt welding flanges designed by flexible and rigid ideas are also compared primarily. Feasibility and security for Q420 and Q460 high strength high-neck forging flanges used in steel tube transmission towers are testified, which provides technical support for their application in UHV transmission project and for future researches.