Effect of Microstructure on Near-Neutral-pH SCC

Abstract

Three components are required for stress corrosion cracking: stress, an environment and a susceptible alloy. The environment that causes near-neutral-pH SCC has been established as a dilute bicarbonate environment and the effect of stress on this type of SCC has received a considerable amount of research; however, the third component, the susceptible alloy, has received little research. The effect of microstructure on near-neutral-pH SCC was investigated using the slow strain rate test. The effect of the microstructure on the corrosion properties is also investigated using polarization resistance tests, potentiodynamic scans and electrochemical impedance spectroscopy. The results indicate that the microstructure influences both the SCC and corrosion behaviour.

Corrosion Evaluation of SAW Welded API 5L X-80 Joints in H2S-Containing Solution

“…Although this film can facilitate hydrogen permeation, it can also act as a physical barrier between the metal and the medium, reducing the corrosion rate 23 . Because these films can vary widely in composition and stoichiometry, the protective effect depends on the conditions of the environment in which they are formed (pH, sulphide concentration, presence of chlorides, formation time, liquid or gas phase and microstructure of the substrate) 2,6,8,9,13,19,21,23 . In the present case, an increase in the corrosion rate was observed for solution 2, which indicates that the formed film was not protective under these conditions.…”

“…As a result, there is an increasing incidence of different types of corrosion in these regions 15,[19][20][21][22][23][24] . In the present work, weight loss tests, scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) were applied to measure the effects of different H 2 S concentrations and pH (3 and 5) on the corrosion process and corrosion product films that were formed on API 5L X80 steel (base metal (BM) and its welded joint (WJ)).…”

Analysis of the Physicochemical, Mechanical, and Electrochemical Parameters and Their Impact on the Internal and External SCC of Carbon Steel Pipelines

“…The microstructure of the carbon steel pipelines contain a ferrite-pearlite phase. Homogeneous microstructures may be less susceptible to SCC [ 127 , 128 , 129 , 130 , 131 , 132 ]. However, these steels have traces of sulfur forming manganese sulfide inclusions (MnS).…”

Assessment of Stress Corrosion Cracking on Pipeline Steels Weldments Used in the Petroleum Industry by Slow Strain Rate Tests

“…The specimens according to the number of repairs were identified as 0R (as-welded), 1R, 2R, 3R and 4R respectively. The experimental research about SCC in pipelines considering the external environment have been studied using NS4 solutions (Elboujdaini et al, 2000;Pan et al, 2006;Bulger & Luo, 2000;Fang et al, 2007;Lu & Luo, 2006), this as results of investigations about the chemical composition of the solution on the surface of the pipeline failed by SCC. The main goal using NS4 solution is to simulate the chemical composition of the soil.…”