Abstract
The basic fatigue strength of welded joints has been investigated on three kinds of steels. Specimens were 20 mm thick, 50 mm wide 500 mm long transverse butt welded joints made by submerged arc welding. The maximum applied stress was held constant to be the yield strength of materials, while the minimum applied stress was varied with the stress range in order to obtain the basic fatigue strength. The yield strength was varied from 284 MPa to 579 MPa. In a long life region, the fatigue strength became superior as the yield strength decreased. It is also suggested that the low yield ratio steel which can be produced by thermo-mechnical control process may have a high fatigue strength.
