Untersuchungen Zur Verbes.spannung.-bestand.einer Geschweis.hoch.al-legier.durch Kugelstrahlen

Author:  Kohler, W.
Source:  Conf Proc: ICSP-1, (p.493-500)
Doc ID:  1981078
Year of Publication:  1981
Abstract:  
The high strength aluminum alloy A1Zn4, 5Mg2 is used already for welded light-weight structures. But the weld seams are very sensitive to stress corrosion. Therefore, an experimental program to improve the corrosion resistance by shot peening has been carried out. Extruded profiles of the alloy were WIG-welded and hereby a tensile strength of Rm = 440 N/mm2 was reached. Samples out of these welded profiles were shot peened with glass-balls of 0,25 o mm. These samples were tested under constant load (75% of the yield strength) in 2% NaC1-Solution on their stress corrosion resistance. Whereas untreated samples cracked by stress corrosion within a few days, with the shot peened samples (0,15 A2) a significant improvement of the life-time up to 61 days without fracture was reached. In addition a great improvement of the fatigue strength was obtained by shot peening. The international compressive stresses were measured by x-ray-method after shot peening. In the heat affected zone compressive stresses of -200 N/mm2 were found. Descriptors: Stress corrosion, Shot peening, Glas-balls, High strength A1-alloy, Weld seam, Fatigue strength, Residual stress