Rolled or extruded sections of Al alloy suitable for welded structures comprise 3.0-5.0, pref. 4.3 wt% Mg, 0.5-1.0, pref. 0.8% Mn, less than 0.25, pref. less than 0.20 and most pref. less than 0.15% Fe, less than 0.25% Si and less than 0.40% Zn. There may be also less than 0.25% Cr, 0.20% Cu, 0.20% Ti and 0.20% Zr. Other elements apart from Al, do not exceed 0.05% each and 0.15% in total, and Mn+2Zn exceeds 0.75% and pref. exceeds 0.8%.
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