The fatigue stress on laser welded joints of DC06EK steel

The paper analyses the influence of the fatigue characteristics of laser welding steels sheets. The combination of laser welded steel sheets DC06EK has been subjected to fatigue stress testing. To assess the condition of the material under the cyclic stress and to determine the material characteristics such as fatigue or resp. fatigue time limit was performed according to STN 42 0363. Fatigue tests were performed on the test piece. The experimental material had a laser weld with a rough surface. The test specimens were subjected to a pulsating positive disappearing thrust at a constant value of the coefficient of unbalance of 0‹R‹1 and a frequency of 25 Hz. The fatigue limit was determined at 260 MPa. The analysis of fracture surfaces showed on the sides of the weld joint the formation of a de-cohesive fracture. The resulting test values graphically presents stress-number curve.