Fatigue Tests and Analysis on Welded Joints of High Strength Steel

Using the one-point experiment and the minimum of specimens expe riment, the fatigue tests on butt and angle welded joints of high strength steel were carried out at the stress ratio 0.12. The effects of butt and angle welded joints on the fatigue life and the fatigue fracture were analyzed with mathemat ical statistics and SEM. The results indicated that the fatigue limit (σ0.12) o f butt welded joints is 230 MPa and the fatigue limit (σ0.12) of angle welded j oints is 130MPa. Meantime, the fatigue curve questions of S-N and P-S-N were ac hieved. The fatigue life of butt welded joints is 6～18 times as long as that of angle welded joints under conditions of 250 MPa stress level and 95% reliabilit y. The main reason is the effect of weld toe and weld crack on the fatigue limit .