VITORINO, Vanine C. Patriota.; VILLAR, Eudésio Oliveira.
Abstract:
The susceptibility to embrittlement by hydrogen in metals and alloys it is common in
environments where it is present from cathodic protection, corrosion processes or as gas. His
interaction with the crystalline matrix of steel contribute to increase the rate of corrosion, thus
facilitating greater penetration of chlorides, water or acid compounds. The weakening of the
metal or alloy can also occur from a combination of aggressive effects of cyclic stress, which
occur, for example, in the marine environment under the mechanical action of the movement of
waves. Several studies have been conducted over time to better understand this mechanism. In
this paper we studied the influence of the sub-superficial hydrogen concentration to some
parameters such as polarization resistance to corrosion (RP) and annual corrosion rate (CR).
To determine the time required for hydrogenation, a computer program was implemented based
on the second Fick law, resulting in a time required to obtained a certain concentration of
hydrogen. The hydrogen was generated from a solution of 0.1 M NaOH using a potential of
1.300V. Tests of corrosion by linear polarization, were performed using a 0.1 M solution of
H2SO4 for the alloys API 5L X60 and X80. The experiments showed that the alloy API 5L X60
has a higher susceptibility to corrosion compared to alloy X80. The latter seems to be more
resistant, probably due to the synergistic effect of its components such as boron, nitrogen and
aluminum.
