Abstract
For the joints with phosphate treatment surfaces of hot-dip galvanized coating, hot-dip galvanized bolts are applied and such bolts are tightened by turn-of-nut method. However, it is unclear how much axial force is induced into the bolts in this joint. The slip coefficient with phosphate treatment surfaces of hot-dip galvanized coating is not also clear. To clarify the induced axial force of the bolts, bolt-tightening tests were carried out. Considering bolt diameter, bolt length, induced axial forces and their relaxation, nut rotation angles are proposed in relation to different bolt size in this paper. In order to examine slip coefficient of the bolted joints with phosphate treatment contact surfaces slip tests of high strength bolted joints were carried out. On the basis of above examinations, the slip coefficient with phosphate treatment surfaces is clarified.
