Submitted Abstract
Corrosion is the weak spot of ArcelorMittal steel piling products for marine waterfront structures. A large part of sheet pilings manufactured by ArcelorMittal in Luxembourg are used for marine applications. During their life, these steel piling retaining structures are partly immersed in seawater and are, therefore, exposed to a harsh corrosive attack in the marine environment (up to 0.1 mm/y of loss of thickness). Due to the critical importance of marine corrosion, steel piling market is facing fierce competition from other materials, especially from concrete, with a risk of losing market shares. R&D activities in this domain is considered as strategic for AM Luxembourg with an ambitious objective of offering commercial products in the next ten years with a reduction of the corrosion rate by one order of magnitude (to 0.01 mm/year). Taking into account the manufacturer’s guaranty as well as the current inability to realize a completely uninterrupted protective barrier on the steel pilling (coating defects cannot be neglected), only a modified metallic surface able of reducing corrosion rate can be considered. METAMARINE project will participate to this objective. The aim of the research works will be to establish an annealing industrial process, at high temperature (T>1000°C) capable of producing an appropriate diffusion profile of Cr guaranteeing the high corrosion protection for steel. To proceed, the idea behind the project is to study the simultaneous growth of an oxide layer protecting the steel during the time needed for the diffusion of Cr. This can be achieved due to the deposition of a Fe-based matrix with a thickness layer of around 10 microns containing Chromium and another metallic element able to develop a compact and stable oxide layer to minimize the generation of mill steel scale.