Investigation on the Welding of High-Strength Aluminum Alloys.

Abstract : The object is to develop methods for improving the strengths of joints in high-strength aluminum alloys. Strength tests were made on welds deposited with No. 716 filler rods in E61S, E24S, and E75S plate. and with experimental filler rods having various silicon-copper ratios, in E61S plate, and a preliminary study of the hot-shortness characteristics of 61S welds and base metal was started. It was found that welds deposited with No. 716 filler wire in the high-strength alloys were stronger, but less ductile, than those deposited with 43S filler wire. A 100 per cent tensile efficiency was developed by a fully heat-treated No. 716 weld in E61S plate. A relationship was observed between the silicon-copper ratio of filler rods containing these elements and their mechanical properties. This alloy system and others containing significant percentages of zinc and of magnesium will be studied further. Examination of welds made with 61S filler, and of 61S base plate, indicated that a low melting eutectic may be causing the hot shortness of this alloy. This will be studied further. The peening tests indicated that no appreciable mechanical improvement resulted from peening the weld metals studied. Heavier peening might cause an improvement, but this is not certain. Further peening tests have been suspended.