Heavy plate or extruded part made of aluminum-magnesium alloy

摘要

The present invention provides a chemistry window and method to manufacture light weight Al-Mg alloy plate materials having significantly improved strength in both soft and work hardened tempers as compared to those of AA5083. It is claimed that the materials produced according to the present invention have ductility, pitting, stress and exfoliation corrosion resistances equivalent to those of the AA5083. Furthermore, it is claimed that the material of current invention has improved long term stress and exfoliation corrosion resistances at temperatures above 80 DEG C which is the maximum application temperature for the AA5083 alloy. The method comprises of the following manufacturing steps: homogenising an alloy ingot containing 4.5-7 % Mg, 0.4-1.2 % Mn, 0.4-5 % Zn, upto 0.3 % Zr, upto 0.3 % Cr, Ti upto 0.2 %, Fe and Si upto 0.5 %, Cu upto 0.4 %: hot rolling the ingot in the range 400-530 DEG C: cold rolling the plate with or without inter-annealing: final and inter annealing the cold rolled material at temperatures in the range 200-550 DEG C.