Organic corrosion protection systems in ships and maritime structures, such as locks, offshore wind turbines or transformer platforms, fail preferentially at highly stressed elements, in particular at welds and free edges as well as in transition areas with varying coating thickness. The reasons for the failure at weld seams are not fully understood yet. This project addresses the investigation of the local behavior of coatings on welds in comparison to the local behavior of the substrate in different conditions. The focus lies on cured coating materials, since these have a limited ductility and cannot follow the local deformations of welds. Particularly unfavorable are the residual stresses of welds and are especially considered in this project.

Within the scope of this project, various shipbuilding/offshore structural elements, which are exposed to particularly high local mechanical stresses, are investigated. Failures regarding coating and corrosion at welds are observed and analyzed. In a test program, various influences, such as coating material application, environmental conditions, surface preparation as well as mechanical stresses are considered. Through a detailed knowledge of failure processes and interrelationships of various aspects an improvement and significant reduction of surface preparation processes prior welding is aspired.

In addition, an environmentally friendly, mechanically flexible and welding-tolerant coating system is to be developed. On the basis of an industrially available laser technology, an alternative surface preparation technique for welds will also be established.

As part of the evaluation of the fatigue strength and cracking of the coating as well as the corrosion behavior, the Institute for Ship Structural Design and Analysis will conduct strength tests of uncoated, coated and post treated welded specimens.

Partners: M10 (Franz von Bock und Polach), Muehlhan AG, Clean-Lasersysteme GmbH, Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Hermann GmbH Maschinenbautechnologie, Sherwin-Williams Deutschland GmbH

Duration: 2022-2025