Hydrogen trapping in an API 5L X60 steel

CASTAÑO RIVERA, PATRICIA; RAMUNNI, VIVIANA PATRICIA; BRUZZONI, PABLO

CORROSION SCIENCE

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2011 vol. 54 p. 106 - 118

0010-938X

Electrochemical hydrogen permeation tests were performed on an API 5L X60 steel to study trapping and diffusion properties in the as-received (AR) and in a cold-rolled (CR) state, at 30oC, 50oC and 70oC. Hydrogen trapping was characterized by assuming saturable traps in local equilibrium. Binding energies (ΔG) and trap densities (N) were determined by fitting a trapping theoretical model to experimental data. Both conditions AR and CR present a high density of weak traps ΔG<35 kJ/mol, namely N = 1.4x10-5 and 7.9x10-4 mol/cm3 respectively. Strong trapping sites were detected (-72<ΔG< -57 kJ/mol) and their densities increased markedly after cold-rolling.