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- Title
On the Change in Hydrogen Diffusion and Trapping Behaviour of Pearlitic Rail Steel at Different Stages of Production.
- Authors
Eichinger, Matthias; Loder, Bernd; Tkadletz, Michael; Schnideritsch, Holger; Klösch, Gerald; Mori, Gregor
- Abstract
To avoid hydrogen flaking in rail production, it is of crucial importance to understand the differences in hydrogen diffusion and trapping between different production steps. Therefore, as-cast unfinished material was compared with two finished rails, hot-rolled and head-hardened, using electron backscattered diffraction (EBSD), electrochemical permeation, and thermal desorption spectroscopy (TDS). A significant increase in dislocation density was in the head-hardened rail compared with the other material states. This leads to an effective hydrogen diffusion coefficient of 5.8 × 10−7 cm2/s which is lower by a factor of four than the diffusion coefficients examined in the other states. Thermal desorption spectroscopy analyses show a clear difference between unfinished and finished rail materials. While a peak in activation energy between 32 and 38 kJ/mol is present at all states, only as-cast unfinished material shows a second peak with an activation energy of 47 kJ/mol, which is related to microvoids. The results show that in the investigated material, the effect of increasing dislocation density has a stronger influence on the effective diffusion coefficient than the presence of a second active trapping site.
- Subjects
PEARLITIC steel; THERMAL desorption; DISLOCATION density; HYDROGEN; DIFFUSION coefficients
- Publication
Materials (1996-1944), 2023, Vol 16, Issue 17, p5780
- ISSN
1996-1944
- Publication type
Article
- DOI
10.3390/ma16175780