In the construction of high-speed ships, aluminum alloy structures are often used to increase the speed of the ship. However, cconsidering cost and durability, the main hull is usually a steel structure, and aluminum alloy is only used for the superstructure to reduce weight, lower the center of gravity, and improve hull performance. Due to the metallic properties of steel and aluminum, they cannot be welded directly. The traditional method can only use riveting connection, that is, welding a steel cofferdam of a certain height on the main deck, and then bolting and riveting the lower edge of the superstructure to the cofferdam with rubber gasket. This method is not only complex in process, but also prone to leakage if the riveting joints are not tightly sealed, affecting the performance of the hull. Composite material transition joints exactly solve this problem, that is, the two materials are connected by welding through the joint. This approach is easy to operate. The joints are solid and continuous and the stress is distributed evenly.
Traditionally, when connecting with rivets or bolts, although there is a rubber insulation layer between steel and aluminum, corrosion and even cracks will still occur after a period of use, shortening the service life of the material. Aluminum-titanium-steel structural transition joints provide an effective maintenance-free weld between steel and aluminum structures. Multiple corrosion tests on the transition joint showed that the joint itself has a natural insulating effect, and corrosion on the aluminum side only begins when the insulating coating or plating is damaged. When the joint interface is connected, a metal joint similar to a sealant will be formed. This substance fills the corrosion gap and prevents electrolyte from penetrating the interface and causing further corrosion. Many studies have shown that structures connected by aluminum-titanium-steel transition joints rarely suffer from galvanic corrosion.