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Hydrogen damage of a welded API 5L X52 steel

Abstract:

The main objective of the present investigation was to study the susceptibility to hydrogen damage on a type API 5L X52 steel welded by electrical resistance. Several techniques, such as hydrogen permeation and cathodic charging, were used. The metallic material was characterized using a scanning electron microscope and transmission electron microscope. The base metal microstructure was very similar to that of the one corresponding to the welded area. This microstructure mainly comprised ferrite and perlite, differing only in the grain size. Therefore, the susceptibility to hydrogen damage was similar in both cases. It is worth mentioning that the welded area has a very small dimension. Indeed, the fusion zone is only 5mm wide while the heat affected zone is 1mm wide. The hydrogen damage observed was mainly in the form of blisters, which were associated with the presence of aluminium-rich inclusions. Also, partial dissolution of inclusions and some matrix attack adjacent to the inclusions were noticed. © 2010 Taylor & Francis.