Measurement and Study on the Torque Coefficient of Ordinary Bolts Before and After Galvanization

Abstract Galvanization is widely applied to bolts as an anti-corrosion method in bolted connection of steel structures in power transmission engineer. After being galvanized by hot-dipping, the torque coefficient of bolts will be changed. To investigate this change, the torque coefficients of ordinary bolts in different grades and specifications were measured before and after galvanization. Results indicate that mean values and standard deviations of torque coefficients of the galvanized bolts increase to a certain extent, but the torque coefficients and the standard deviations tend to decline as the improvement of bolt specification, and the stress of ungalvanized ones is larger than that of hot-dip galvanized bolts in the same grade and specification.