Dissimilar Welded Joints for Ship Structures

Shipbuilding and offshore structures involve a variety of metallic materials, from standard steel to high-strength steels, and aluminium and titanium alloys. Welding is undoubtedly the primary connection technique, but joining different materials remains a significant challenge. The explosion welding (EW) technique has been increasingly applied for joining dissimilar metallic materials, due to potential technical complications like metallurgical incompatibility associated with conventional welding techniques. EW is typically described as a solid-state joining process that uses an explosive detonation as the energy source to create a metallurgical bond between metal components. This process results in partial melting at the wavy interface and the formation of intermetallic, which can lead to cracking when exposed to dynamic loading. An application of bimetallic EW joints in shipbuilding is the connection of an aluminium superstructure to a steel deck. The aim of this research is the evaluation of the mechanical behaviour of aluminium/steel explosion welded joints for ship structures. The investigated EW joints consist of ASTM A516 Gr55 structural steel, clad by explosion welding with AA5086 aluminium alloy with an intermediate layer of AA1050 commercial pure aluminium. Tensile tests were carried out by using full-field techniques, such as Digital Image Correlation and Infrared Thermography. Moreover, fracture mechanics tests were carried out on Compact tension (CT) EW aluminium/steel specimens.