It is our greatest pleasure to welcome you to the Fourth International Conference on Metals and Hydrogen; Steelyhydrogen 2022. After the successful editions of Steelyhydrogen in 2011, 2014 and 2018, the global pandemic made the preparation and organisation of this edition very uncertain. Nevertheless, here we are, with the highest number of participants of all 4 editions and even in majority physical attendance. The number of proposed contributions continued to increase compared to the previous editions and this 3-day event now brings together more than 40 presentations and more than 60 posters from all over the globe.

This year the conference venue is set in the unique location of a historic monastery where Augustinian monks still live and work (Thagaste) in the historic heart of Ghent. Although the monastery is an oasis of peace, Thagaste represents the modern function of the monastery: a place where people meet, where they exchange ideas, and where they can simply enjoy being together, all nestled in a historic setting. We hope this spirit grasps every participant and that numerous fruitful discussions initiate during this conference. In this respect, the coffee breaks have been extended based on prior edition feedback to promote exchanges between the participants.

The scope of the conference remains as before, i.e. scientific research on the interaction between hydrogen and metals, investigated from different perspectives with various approaches, e.g. computational as well as experimental work, applied and fundamental research, substrate and surface aspects, mechanical effects as well as internal hydrogen management aspects such as pick-up, trapping etc. From an initial focus on steel substrates, we opened the scope of the previous conference edition to other metals and we continue to dedicate specific sessions to other metals.

The climate challenges that our society faces and the related enormous re-boost of interest in hydrogen as energetic vector, is logically reflected in the program of this conference with several dedicated sessions related to the behaviour of hydrogen in metals for the global energy transition.

From all the submissions we aimed for a well-balanced program of presentations satisfying an audience with multiple interests. This implied to blend industrial problematics with theoretical studies as well as methodological developments.  The number of poster sessions has been extended to allow more time for exchange and discussion. As for the previous conferences, we targeted the proceedings to be ready at the start of the conference as feedback indicated it is a real added value for the participants. We would therefore like to sincerely thank all the authors for their in-time and valuable contributions. The best presentation and best poster of the conference will be selected by the members of the scientific jury and will be awarded in the closing ceremony.

We wish you lot of interest while exploring this e-book and hope that you will have stimulating interactions during these three days.