Design optimisation problems of stress corrosion in welded joints in 7000 alloy

Abstract

The use of thick plates of high-strength aluminium alloys, in specific welded structures, gives the designer many optimisation problems concerning the prediction and elimination of brittle fracture in the welded joints, caused by stress corrosion in the zone next to the weld beads. The Istituto Sperimentale dei Metalli Leggeri has faced and worked out these problems, in parallel with investigations of a metallurgical nature concerning the microstructural characteristics of the base metal in the heat affected zone (HAZ) next to the weld.

The results of these studies enabled us to define, with the aid of appropriate structural calculation techniques, some design schemes which ensure a high resistance to brittle fracture by stress corrosion in special welded joints. This paper investigates and discusses such problems.