Fatigue strengths of welded butt-joints of Al-Mg alloys
Studies of fatigue strengths of aluminum alloys for welded construction (1st Report)
1968 Volume 18 Issue 2 Pages 71-80
Details
1968 Volume 18 Issue 2 Pages 71-80
In recent years, Al-Mg and Al-Zn-Mg alloys have widely been used as structural materials because of their good fusion weldability and progress in welding technique. This report summarizes several research experiments for fatigue properties of welded butt-joints of 5052, 5056, and 5083 aluminum alloys in MIG or TIG welding.
The fatigue tests of the materials of 4-6mm in thickness were conducted with Schenck's plane-vibrating fatigue tester and the tests of round-bar specimens obtained from plates of 20mm in thickness were conducted with Ono's rotary-bending fatigue tester. The values of fatigue strengths were determined by 107 cycles.
The number of blow holes had no remarkable effects on fatigue strength of butt-jointed specimen having reinforcement of weld. When there were no defects on the surfaces of the finished specimen, the fatigue strengths of welded specimen approached those values of annealed base metals. These results are summarized in Fig. 5.
The effects of filler metals employed for the fatigue strength of 5083-O alloy in MIG welding are shown in Fig. 8. The effects of the shape of reinforcement of weld or presence of blow holes on the surfaces of the finished specimen were more powerful than those of filler metals employed.
Above results were obtained from the experiments on materials of 4-6mm in thickness. In the welded butt-joint of 20mm in thickness, the fatigue strengths of finished round-bar specimens, having welded zone in parallel part, were about 33% lower than those of the base metals. These values of the strengths of the specimens approximately corresponded to those of the cast materials as shown in Table 10.
