BOLT-TIGHTENING TESTS OF HIGH STRENGTH BOLTED JOINT WITH METAL-SPRAYED CONTACT SURFACES

Abstract

 For the joints with metal-sprayed surfaces, hot-dip galvanized bolts are applied and such bolts are tightened by turn-of-nut method. However, it had been unclear how much axial force is induced into the bolts in the joints with metal-sprayed surfaces. To clarify the induced axial force of the bolts, we had carried out bolt-tightening tests. On the basis of above examinations, we had been proposed nut rotation angles in relation to different bolt size. In this paper, to confirm the induced axial force of the bolts, bolt-tightening tests were carried out using the proposed nut rotation angles. Considering bolt diameter, bolt length, coating thickness, induced axial forces and their relaxation, the applicable conditions of the proposed nut rotation angles were clarified.