Hydrogen permeation and hydrogen content under cathodic charging in HSLA 80 and HSLA 100 steels

Hydrogen-induced cracking and healing behaviour of X70 steel

“…where d is the specimen thickness and t L the time-lag in seconds for 0.63 saturation, which is extrapolated from the permeation curve [6].…”

“…So far, investigations on the HIC of steel have primarily been focused on the formation process of cracks including theoretical analysis [5][6][7]. However, little attention has been given to the healing process of cracks induced by hydrogen charging.…”

The Pitting Susceptibility Investigation of Passive Films Formed on X70, X80, and X100 Pipeline Steels by Electrochemical Noise and Mott-Schottky Measurements

“…The microstructural features of X70, X80, and X100 pipeline steels were examined with optical microscope, as shown in Figure 1. It can be seen that X70 steel ( Figure 1(a)) exhibited a complex microstructure including fine acicular ferrite (AF) and granular bainite (BF), which gave rise to high strength of pipeline steel [23,24]. The microstructure of X80 steel (Figure 1(b)) may be a combination of polygonal ferrite (PF) and granular bainite (BF), and X100 steel (Figure 1(c)) was also mainly composed of AF, BF, and martensitic-austenitic particles (M-A) distributed along the grain boundaries, and M-A phases can improve significantly the strength of X100 pipeline steel as the second phase.…”

Effect of cathodic potentials on the SCC behavior of E690 steel in simulated seawater

“…Thus, the mobile hydrogen content and hydrogen trapped in the bainitic lath boundaries increased drastically [33,34]. Since the separation of lath boundaries will only take place if the hydrogen content exceeds a threshold value which in turn depends on the cathodic potential level, time of exposure, specific lath boundary dimension and hydrogen trapping capacity, etc., the bainitic lath boundary separations would be much more severe with the negative shift of cathodic potential leading to a higher susceptibility to SCC.…”