Structural transition joints (STJ) are bimetal strips that make it possible to weld different metals together. These strips are mainly used when two metals cannot actually be connected to each other. If a conventional welding process is not possible, a mechanical joining technique should normally be used. With transition joints, the use of these mechanical connection techniques has become obsolete. These mechanical joining techniques have the disadvantage that corrosion can occur after a relatively short period of time. Obviously, this is highly undesirable in various industries. Due to the advantages of joining aluminium and steel, structural transition joints (STJ's) are widely used in shipbuilding. But what is a structural transition joint exactly?

Structural Transition Joints are able to join a wide range of materials that would otherwise have to be mechanically fastened. STJ's are used in the shipbuilding industry becausethe joining of these materials saves weight and exploits the best properties of both materials.

History of Structural Transition Joints

Shipbuilders are familiar with the advantages of Structural Transition Joints for years now. The possibility toweld aluminium and steel together expands the lifetime of a ship.

In the past, there were more traditional ways of attaching these metals to each other, such as riveting and bolted joints. For years these techniques have been used, but these ways of joining steel and aluminium together have some major disadvantages. One of the main disadvantages is the occurrence of corrosion. This is mainly due to the large differences between the thermal expansion coefficients of aluminium and steel. In case this happens, seawater can seep into the metal compound (causing corrosion). When corrosion occurs, there are just a few solutions left to save the boat: replace the entire transition between steel and aluminium or replace the entire wheelhouse. Both options are of course very expensive. It has become clear that several industries needed another way of joining aluminium and steel together. Therefore, structural transition joints are widely used inshipbuilding nowadays.