The effect of Nb on the hydrogen embrittlement susceptibility of Q&P steel under static and dynamic loading

The effect of Nb on the hydrogen embrittlement susceptibility of Q&P steel under static and dynamic loading

Vercruysse, Florian (Universiteit Gent)
Claeys, Lisa (Universiteit Gent)
Depover, Tom (Universiteit Gent)
Verleysen, Patricia (Universiteit Gent)
Petrov, R.H. (TU Delft Team Jilt Sietsma; Universiteit Gent)
Verbeken, Kim (Universiteit Gent)

2022

In the present study, the effect of Niobium (Nb) on the hydrogen embrittlement resistance of Quenched and Partitioning (Q&P) steel is investigated. For this purpose, the hydrogen uptake level and its impact on the mechanical properties of a Nb-free and a 0.024 wt% Nb Q&P steel are thoroughly analysed. The hydrogen trapping capacity is evaluated via thermal desorption spectroscopy (TDS). In-depth analysis of the desorption kinetics at different heating rates allows identification and quantification of the available trapping sites. The hydrogen embrittlement sensitivity of both steels is characterized using static and dynamic tensile tests. The addition of Nb results in an increase of the hydrogen concentration by more than 25%. The larger hydrogen content in the Nb steel, as a result of the higher fraction of grain boundaries/interphases, gives rise to a more severe embrittlement of the Nb steel compared to the Nb-free one. In addition to the larger hydrogen fraction in the Nb Q&P steel, the larger retained austenite fraction of low stability is detrimental due to the larger fraction of high carbon martensite formed when straining. This results in higher susceptibility to hydrogen embrittlement of the Nb microalloyed steel due to the brittle character of the high carbon martensite that forms easily during straining. Under dynamic loading conditions, the hydrogen embrittlement of both steels is minimal, which is attributed to a reduced hydrogen diffusion and the suppression of the transformation induced plasticity (TRIP) effect due to adiabatic heating.

Dynamic loading
Hydrogen embrittlement
Martensitic transformation
Niobium alloying
Q&P steel

http://resolver.tudelft.nl/uuid:c8090ce6-b1d1-42b1-8097-7d32e870abe1

https://doi.org/10.1016/j.msea.2022.143652

2023-07-01

0921-5093

Materials Science and Engineering A: Structural Materials: Properties, Microstructures and Processing, 852

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

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© 2022 Florian Vercruysse, Lisa Claeys, Tom Depover, Patricia Verleysen, R.H. Petrov, Kim Verbeken