Weldable aluminium alloy sheet - with good mechanical properties and very high corrosion resistance

摘要

Parent Patent described weldable Al alloy sheet with superior mechanical properties and corrosion resistance when compared with A-G5 or AZ5G sheets. The cast plate is homogenised 6-50 h at 400-540 degrees C., then hot rolled to intermediate thickness (IT) with end temp. over 370 degrees C.; quenched to room temp.; cold rolled to final thickness (FT); and heated at 200-380 degrees C for a few minutes. In this addn., the cast plate has compsn. 3.5-5% Mg 1.5-3% Zn, and all maxima, 0.35% Si, 0.4% Fe, 0.3% Cu, 0.4% Mn, 0.15% Cr, 0.3% Zr, 0.05% other elements, the remainder being Al. Pref. alloys contain (a) 0.04% Cr; (b) below 0.04% Cr and 0.2% Mn; and (c) 0.04% Cr and 0.05% Mn. Resistance to flake corrosion is improved.