The nonprofit research institute Lazer Zentrum Hannover eV (LZH) will work with industry partners and scientists to solve the challenges of joining steel and aluminum in maritime construction. To that end, the Laser Welding of Steel to Aluminum for Applications in Shipbuilding (LaSAAS) project aims to develop, test, apply and verify a laser processing head and welding process. Currently in shipbuilding, different metals are joined using an adapter piece with an explosive cladding process, which is a complicated and cost-intensive joining technology. Laser welding of steel to aluminum. Courtesy of Laser Zentrum Hannover. LaSAAS aims to replace this adapter piece. System manufacturers Precitec GmbH & Co. KG, Scansonic MI GmbH, and Trumpf Laser- und Systemtechnik GmbH are working with LZH to develop a laser processing head with a weld-penetration depth control. Using the processing head, LZH will develop a welding process under lab conditions to be tested in cooperation with Laser on Demand GmbH. Afterward, the process will be transferred to actual applications by semifinished product manufacturers Druckguss Service Deutschland GmbH and Hilbig GmbH, as well as the shipyards Fr. Lürssen Werft GmbH & Co. KG and Meyer Werft GmbH & Co. The Fraunhofer Institute for Structural Durability and System Reliability will examine the fatigue behavior of the seams, especially under the influence of corrosive media. When thermally welding steel to aluminum, brittle intermetallic phases occur, which can cause premature failure under stress. However, weld-seam characteristics and weld-penetration depth can be optimized based on the mix ratio of the metals; LaSAAS project partners plan to control weld-penetration depth by analyzing the spectral process emissions using short-coherence interferometry. The project is funded by the German Federal Ministry for Economics and Energy and supervised by Forschungszentrum Jülich GmbH, an interdisciplinary research center.