On the Fatigue Strength of Welded Aluminum Alloys

Abstract

Fatigue tests of mother and welded metals were done on Aluminum alloys used for welded structure. Four kinds of Al-Mg alloys (work hardened alloys), two kinds of Al-Zn-Mg alloys (age hardened alloys) and three kinds of forged Aluminum alloys were tested. Plane bending fatigue test was adopted to get the fatigue strength, and stresses obtained by measuring surface strains of each specimen were used to analyze the test results. Main results obtained were as follows ; (1) For the tested matererials, the relatios between ∂_a/∂_y and ∂_y or H_v were represented approximately by linear functions at each number of cycle within the range of 10^4∼10^7. (2) Blow-holes due to welding did not have any effect on the fatigue strength of each alloy. (3) It is very likely that the improvement of hardness of the welded Al-Zn-Mg alloys, which may concern with the improvement of the fatigue strength of welded part, can be stimulated effectively by artificial heating at about a temperature of 80℃.