The main objective of the WeldGreenPlate proposal is to define the conditions for safe use of green structural steels, if possible without the use of critical strategic elements, for European infrastructures made of medium strength (S355) to ultra-high strength (S960) steels. To achieve this goal, the most critical locations in these structures will be investigated: the welded joints and in particular the HAZ.

Future green steels will be manufactured using an increased amount of scrap, likely of lower quality and containing higher concentrations of residual elements (Cu, Ni, Cr, Mo, Sn, As, Sb, Pb, Zn, Bi and Co). This will modify the chemical composition of the steel grades and thus the response of the material to thermal cycles, such as imposed by welding. The

properties of welded joints will therefore be changed, making it necessary to assess these changes and remedy them, if required.

The proposal will investigate modified alloying concepts for the safe application of clean steel in downstream processing and fabrication. It is planned to investigate the application of multiple welding repairs to allow re-use of fabricated components and give the opportunity to have steel solutions with improved CO2 emissions through re-use of fabricated

components.The improved or non-degraded weldability will allow to develop new clean steel grades with improved in-use properties, particularly strength and toughness in the welded conditions, through application of state-of-the-art techniques: machine learning, thermodynamic simulations, FEM of microstructural behaviour, supported by advanced

analytical techniques. The latest items are innovative tools that will be available to future clean steel grades development.

It is in the scope of the project to find the requirements for high-performance structure steels characterized by increased tolerance to contaminants in the scrap, in particular Cu.