Study on stress-corrosion cracking at plate-edge of fillet weld in commercial Al-Zn-Mg alloy thick plates

Abstract

Stress-corrosion cracking at plate-edge of fillet weld is influenced by the distance from weld to plate-edge L, plate thickness T, small amount of additional elements, temper of base metal and test circumstance. No stress-corrosion cracking occur if L≥20mm(L/T≥1 in 20mm thick plate). Stress-corrosion cracking takes place at surface side of 1/41/5 of plate thickness having residual stress more than 810kg/mm² and corresponding to the region of revrsion caused by weld heat input. No stress-corrosion cracking occur in the overaged region even if higher residual stress exists. Stress-corrosion cracking tends to occur most in T4 temper and least, in T7 one, though the effect of tempers of T4, T6 and T7 is comparatively small. The addition of small amount of copper is considerably effective to prevent stress-corrosion cracking.