Yanliang Huang

Effect of H2S on stress corrosion cracking and hydrogen permeation behaviour of X56 grade steel in atmospheric environment

Abstract Susceptibility to stress corrosion cracking of X56 steel and its relationship with hydrogen permeation behaviour in atmospheric environment containing H2S was investigated by hydrogen permeation tests at a slow strain rate. The results show that: the fracture strain decreases with the decrease of strain rate under the same experimental conditions; the fracture strain also decreases with the increase of H2S concentration under the same strain rate, and the increased concentration of H2S has no significant effect on the hydrogen permeation in the first wet, etc. dry cycle, however has lead to increased hydrogen permeation in the later cycles. The SEM images of the fractured surfaces show clear evidences of enhanced stress corrosion cracking susceptibility by H2S.

Effect of heat treatment on hydrogen permeation behaviour of AISI 4135 steel under splash zone conditions

Effect of heat treatment on the hydrogen permeation behaviour of AISI 4135 steel was studied by electrochemical method under simulated splash zone conditions. The hydrogen permeation current reached maximum at dry stage and the amount of hydrogen permeated showing a maximum in sixth cycle. Moreover, it was found that the amount of hydrogen permeated through specimen with bainitic microstructure was lower than that in other specimens. The average value of charge transfer resistances for heat treated specimens A, B, C and D exhibit no significant differences under nature sea water film. Moreover, the heat treatments have no prominent impact on corrosion products from the X-ray diffraction (XRD) pattern and SEM analysis. Therefore, the differences in hydrogen permeation behaviours were mainly attributed to the microstructures of specimens other than the differences in corrosion behaviour.

Corrosion behaviour of carbon steel, titanium and titanium alloy in simulated underground water in Beishan area preselected for nuclear waste repository in China

ABSTRACT The groundwater will completely infiltrate to the surface of nuclear waste container after the closure of its deep geological disposal. Therefore, the corrosion behaviour of Q235 carbon steel, titanium and titanium alloy, which were the candidates as the container materials for high-level nuclear waste disposal in simulated groundwater solution of Beishan to be served as the preselected high-level nuclear waste disposal area in China at different temperatures, was studied through electrochemical methods including open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarisation curve measurements. The results show that the corrosion rate of titanium and titanium alloy is lower than that of carbon steel at all temperatures, and they are more promising as container materials. Another phenomenon is that higher temperatures facilitate the protection performance of corrosion products compared with lower temperatures.

Investigation on role of corrosion generated hydrogen in process of stress corrosion cracking of austenitic stainless steel in marine atmospheric environment

Abstract Evidence on the role of corrosion generated hydrogen in stress corrosion cracking of austenitic stainless steel in marine atmospheric environment is provided. The formation of corrosive solution film on the surface of steel was observed. Hydrogen permeation through the stainless steel membrane was measured. Slow strain rate tests showed that anodic and cathodic polarisations around the free corrosion potential can both increase the elongation. Thermal desorption spectroscopy measurement showed hydrogen concentration increase under cathodic potentials. The hydrogen concentration increase under deformation conditions was also confirmed. However, hydrogen accumulation at the tip of the prenotched specimens was not detected.