Electrochemical and Tension Tests Behavior of API 5L X60 Pipeline Steel in a Simulated Soil Solution

2013 ◽  
Vol 755 ◽  
pp. 153-161 ◽  
Author(s):  
Luis M. Quej-Aké ◽  
Ricardo Galván-Martínez ◽  
Antonio Contreras-Cuevas
Keyword(s):  
Carbon Steel ◽  
Strain Rate ◽  
Soil Solution ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Failure Process ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Tension Tests ◽  
Before And After

In this work electrochemical impedance spectroscopy (EIS) and slow strain rate tests (SSRT) were used for the evaluation of API 5L X60 carbon steel in contact with a simulated soil solution called NS4. EIS monitoring before and after performing the tension tests was carried out. SSRT were carried out in NS4 solution at room temperature to simulate dilute ground water that has been found associated with stress corrosion cracking (SCC) of low carbon steel pipelines. A strain rate of 1x10-6 sec-1 was used. According to the analysis of SSRT, the X60 pipeline steel is highly resistant to SCC. In order to perform the electrochemical test, two working electrodes were considered, a complete specimen, before the SSRT and a fractured specimen after the SSRT. The analyses of results show that the electrochemical response was different in each samples. The corrosion rate (CR) obtained by the two corrosion techniques revealed that the CR of the fractured specimen was higher than the CR of the complete specimen. This behavior is attributed to the fact that the fractured specimen present a high degree of tortuosity and this condition activate the corrosion process. In addition, according to the cathodic Tafel slope, the reduction reacction was influenced by a difusion process. A combine fracture type in SSRT was observed: ductil and brittle with a transgranular appearance. Some pits and internal cracks close to the fracture zone were observed. The failure process and mechanism of X60 steel in NS4 solution are controlled by dissolution and hydrogen embrittlement.

Tension Tests Behavior of API 5L X60 Pipeline Steel in a Simulated Soil Solution to Evaluate SCC Susceptibility

2012 ◽  
Vol 1481 ◽  
pp. 71-80
Author(s):  
A. Contreras ◽  
S. L. Hernández ◽  
R. Galvan-Martinez ◽  
O. Vega-Becerra
Keyword(s):  
Strain Rate ◽  
Soil Solution ◽  
Room Temperature ◽  
Pipeline Steel ◽  
Failure Process ◽  
Low Carbon Steel ◽  
Fracture Type ◽  
Low Carbon ◽  
Surface Fracture ◽  
Tension Tests

ABSTRACTIn this work slow strain rate tests (SSRT) were used for the evaluation of API 5L X60 in contact with a simulated soil solution called NS4 in order to evaluate stress corrosion cracking (SCC) susceptibility. SSRT were carried out in NS4 solution at room temperature to simulate dilute ground water that has been found to be associated with SCC of low carbon steel pipelines. A strain rate of 1x10-6 sec-1 was used. According to the analysis of SSRT results, the X60 pipeline steel is highly resistant to SCC at the conditions studied. A combine fracture type it was observed: ductile and brittle with a transgranular appearance. Some pits close to the fracture zone were observed. The failure process and mechanism of X60 steel in NS4 solution are controlled by anodic dissolution and hydrogen embrittlement which was revealed with the internal cracks observed in the surface fracture. There is a relation between the strength of the steel and the SCC susceptibility, thus, increasing strength in the steel, the SCC susceptibility increases as a function of the pH solution used.

Phenylcoumarin Glucoside as a Natural Inhibitor in the Protection of Low Carbon Steel Against Corrosion

MRS Advances ◽  
2017 ◽  
Vol 2 (62) ◽  
pp. 3909-3915
Author(s):  
Héctor M. Barbosa Cásarez ◽  
Araceli Espinoza Vázquez ◽  
Francisco J. Rodríguez-Gomez
Keyword(s):  
Carbon Steel ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Low Carbon Steel ◽  
Steel Corrosion ◽  
Low Carbon ◽  
Low Concentrations ◽  
Natural Inhibitor ◽  
Polarization Studies

AbstractPhenylcoumarin glucoside (4-PC) is a compound extracted from the plant Hintona latiflora and was studied as inhibitor for AISI 1018 steel corrosion in 3% NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques, which may find application as eco-friendly corrosion inhibitors. The 4-PC provides inhibitor properties that protect AISI 1018 low carbon steel against corrosion at low concentrations (5 ppm) obtained by EIS. Polarization studies showed that the inhibitor was of mixed type. The inhibition efficiency by the two electrochemical techniques shows similar results. The inhibitor adsorption was demonstrated to be a combined process (physisorption and chemisorption) according to the Langmuir isotherm.

Corrosion Behavior of Al-Si-Cr-Cu Bearing Low Carbon Steel in A Cyclic Dry/Wet Laboratory Test

2009 ◽  
Vol 79-82 ◽  
pp. 1017-1020 ◽  
Author(s):  
Hui Shu Zhang ◽  
Dong Ping Zhan ◽  
Song Lian Bai ◽  
Zhou Hua Jiang
Keyword(s):  
Carbon Steel ◽  
Electrochemical Impedance ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Low Carbon ◽  
Rust Layer ◽  
Electrochemical Behaviors ◽  
Corrosion Rates ◽  
The Matrix ◽  
Corrosion Behaviors

The corrosion behaviors of Al-Si-Cr-Cu bearing low carbon steel and a reference steel Q235 were tested in a cyclic dry/wet environment containing 0.01mol/L NaHSO3 in laboratory. Rust layers were observed by optical microscope (OM), scanning electron microscopy (SEM) and XRD. The electrochemical behaviors of the steels were studied on the polarization curves and electrochemical impedance spectroscopy (EIS). The results indicate that after 120h corrosion test, the annual corrosion rates of the designed steels reduce 42 % than Q235 at least. The corrosion products are generally iron oxyhydroxides and oxides such as FeOOH, γ-FeOOH, α-FeOOH, γ-Fe2O3, Fe3O4. The α-FeOOH possesses good stabilization mainly exits and can improve the corrosion resistance. There are the enrichments of Cu, Cr, Si and Al in the rust layer close to the matrix, which make the rust layer be more compact and protected. The corrosion currents of the two designed steels are lower than that of Q235, the corrosion potentials are higher than that of Q235 after Tafel fitting. The rust layer impedances of the designed steels are higher than that of Q235.

Effect of Nanoparticle Addition in Hybrid Sol-Gel Silane Coating on Corrosion Resistance of Low Carbon Steel

2013 ◽  
Vol 686 ◽  
pp. 244-249 ◽  
Author(s):  
Poovarasi Balan ◽  
Aaron Ng ◽  
Chee Beng Siang ◽  
R.K. Singh Raman ◽  
Eng Seng Chan
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Low Carbon Steel ◽  
Electrochemical Corrosion ◽  
Alumina Nanoparticles ◽  
Low Carbon ◽  
Silane Coating ◽  
Sol Gel Films

Chromium pre-treatments of metal have been replaced by silane pre-treatments as more environmental friendly option. Nanoparticles can be added in the silane sol-gel network have been reported to improve corrosion resistance. In this work, the electrochemical corrosion resistance of low carbon steel coated with hybrid organic-inorganic sol-gel film filled with nanoparticles was evaluated. The sol-gel films have been synthesized from 3-glycidoxy-propyl-trimethoxy-silane (3-GPTMS) and tetra-ethyl-ortho-silicate (TEOS) precursors. These films have been impregnated with 300 ppm of silica or alumina nanoparticles. The electrochemical behavior of the coated steel was evaluated by means of electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Equivalent circuit modeling, used for quantifying the EIS measurements showed that sol-gel films containing silica nanoparticles improved the barrier properties of the silane coating. The silica nanoparticle-containing films showed highest initial pore resistance over the five days of immersion in 0.05M NaCl.

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