Short fatigue cracks on the welded steels construction surface

In this study; 17Mn4 (P295GH) pressure vessels steel and AISI 304 stainless steel were welded with ER 309L austenitic consumable. Hardness and tensile tests were done on specimens of welding plates.8 x 8 x 100 mm specimens were fatigued with four point bending. Stresses under the yield strength of AISI 304 were applied, fatigue device was stopped at the every 100 000 cycles and the specimens were examined on the optical microscope. When the crack was seen, a photo of crack was taken and the diameter of the crack was measured. After the crack initiation, examinings were started performing at every 50 000 cycles.In the theoretical part of the study, finite element analysis (FEA) were conducted by fixing 2-D models with element thickness. Stress and fatigue analyses were performed for the different stresses. After determining the stress distribution on the models, fatigue behavior of the welded specimens was investigated on the surfaces where the tensile stresses had maximum values. Besides the welded materials precracked on AISI 304 stainless steel were modelled as 2D and J integral values were calculated for the crack.Keywords: ANSYS, Fatigue, Short fatigue cracks, Fracture