Study of the durability of high-strength steels in the marine environment

As the demand for clean energy grows, the importance of robust and durable structures for offshore wind energy becomes paramount. Due to their exceptional mechanical properties, ultra-high-strength steels (UHSS) are increasingly used. However, high-strength steels are susceptible to hydrogen embrittlement (HBE). Hydrogen embrittlement results in significant property deterioration and can lead to catastrophic failure under loads below design limits.

One strategy for manufacturing high-strength steels (UHSS) is to employ quenching and tempering processes. Heat treatments substantially alter the microstructure and mechanical properties. The microstructure and the presence of inclusions are key elements in resistance to hydrogen cracking. In other words, the microstructure is involved in both hydrogen transport processes and the embrittlement mechanisms themselves. Therefore, heat treatments play a fundamental role in the HBE phenomenon. The hardest, acicular-shaped microstructures are the most susceptible to hydrogen damage.

Another factor or condition that influences HPF is the environment (the source of hydrogen supply). The ability to introduce hydrogen depends on the aggressiveness of the medium.

In this work, the hydrogen diffusion kinetics (ASTM G148-18) of three high-strength quenched and tempered steels in a synthetic marine environment according to ASTM D1141-98 were studied. The objective was to understand how hydrogen interacts with the material’s crystal red, in order to complete the interpretation of the influence of microstructure on the HPF phenomenon.