Shipboard Aluminum/Steel Welded Transition Joints: Evaluations and Improvements

Abstract

Aluminum-to-steel explosion-welded transition joints are used to attach aluminum superstructures to steel hulls. Transition joint bond separation sometimes occurs during ship construction. Ingalls Shipbuilding conducted a long-term study to determine causes and corrective action for these separations. Aluminum/steel transition joints are manufactured by the explosion-bonding process and tested in accordance with MIL-J-24445. Traditional transition joints consist of alloyed aluminum bonded to mild steel with an interlayer of low-alloy aluminum. The study reviews transition joint manufacture and quality testing required by material specification, adequacy of design guidelines and production practices, and cost-effective methods for corrective action. Modifications in product design and testing, installation design and shipyard production practices can improve reliability. The most important result of this study was development of material with improved properties. This paper relates the study procedure, findings and recommendations so that transition joint separations can be avoided on future installations. This information is useful for designers and transition joint users