Abstract
In this paper, the exposure tests of the new super high tension bolts which have the tensile strength about 1500 N/mm^2 are described and the results of these tests are considered. The new super high tension bolt has the improved thread shape of which elastic stress concentration factor would be reduced to the 60% value of the conventional high tension bolt thread shape. The exposure tests are the accelerated exposure test by Eto's method and the actual exposure tests at four different climatic places in Japan. The exposure tested bolts are the conventional F10T bolt and the new super high tension bolts. And these new super high tension bolts are made from two new materials which have the higher critical diffusible hydrogen contents than that of the conventional F10T bolt.
