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Simulation of Mild Steel Corrosion in H2S Aqueous Solution
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
Corrosion is a main problem for oil and gas industries at refineries and petrochemical process. Presence of sulfur compounds in crude oil and creation a corrosive environment for steel structure, caused failure and unfortunate damages. H2S which present at cracking and sweetening process in sour feed obtain hydrogen atoms that can diffuse into steel structure which involve with its instruments and consequent to hydrogen damage .distribution and storage of these sour environments can be done by high strength low alloy steel (HSLA).Electrochemical hydrogen permeation test were performed to measure the hydrogen permeation current through A106/GR B pipeline steel in the electrolytes simulating...
Corrosion investigation of pipeline steel in hydrogen sulfide containing solutions
, Article Journal of Applied Sciences ; Volume 12, Issue 23 , 2012 , Pages 2454-2458 ; 18125654 (ISSN) ; Taheri, H ; Ismail, M. C ; Dolati, A ; Sharif University of Technology
Abstract
The hydrogen-induced cracking (HIC) behavior of X70 pipeline steel was studied by means of Linear Polarization Resistance (LPR), hydrogen permeation tests, weight loss and Scanning Electron Microscopy (SEM). In this study, the dissolved HZS was created by chemical reactions in solution. The specimens were immersed into synthetic sea water saturated with HZS. The experimental results showed that the increase of exposure time and HZS concentration leads to an increase of the hydrogen content in X70 steel, which plays a key role in the initiation and propagation of HIC
Control of hydrogen cracking in the welded steel using microstructural traps
, Article Materials Science and Technology (United Kingdom) ; Volume 33, Issue 4 , 2017 , Pages 408-414 ; 02670836 (ISSN) ; He, P ; Kokabi, A. H ; Dolati, A ; Sharif University of Technology
Taylor and Francis Ltd
2017
Abstract
Hydrogen diffusion into steel can embrittle the material in H2S environments, but this effect can be offset by suitable hydrogen trapping sites in the microstructure. Fine Ti(C,N) inclusions have been studied as the trapping sites in high strength low alloy (API X-70) welds, with Ti additions ranging from 0.004 to 0.16 wt.%. The trapping sites were investigated by electron microscopy and thermal desorption spectroscopy. Manganese sulphide particles were the main initiation sites for hydrogen induced cracking as expected. The optimum Ti addition was around 0.02% with no evidence of cracking in the weld. The estimated values of trapping activation energy for dislocations, microvoids, MnS and...
Micro-scale evolution of mechanical properties of glass-ceramic sealant for solid oxide fuel/electrolysis cells
, Article Ceramics International ; Volume 47, Issue 3 , 2021 , Pages 3884-3891 ; 02728842 (ISSN) ; Malzbender, J ; Groß Barsnick, S. M ; Abdoli, H ; Kokabi, A. H ; Faghihi Sani, M. A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The structural integrity of the sealant is critical for the reliability of solid oxide cells (SOCs) stacks. In this study, elastic modulus (E), hardness (H) and fracture toughness (KIC) of a rapid crystallizing glass of BaO–CaO–SiO2 system termed “sealant G” are reported as determined using an indentation test method at room temperature. A wide range of indentation loads (1 mN–10 N) was used to investigate the load-dependency of these mechanical properties. Values of 95 ± 12 GPa, 5.8 ± 0.2 GPa and 1.15 ± 0.07 MPa m0.5 were derived for E, H and KIC using the most suitable indentation loads. An application relevant annealing treatment of 500 h at 800 °C does not lead to a significant change of...
Investigation of the effect of pad geometry on flat and rounded fretting fatigue
, Article Scientia Iranica ; Volume 15, Issue 3 , 2008 , Pages 332-339 ; 10263098 (ISSN) ; Farrahi, G. H ; Sharif University of Technology
Sharif University of Technology
2008
Abstract
In this paper, the effect of geometrical parameters on the fretting fatigue of a half-plane in contact with a flat and rounded pad is studied. This is accomplished by calculating and comparing the stress states and stress intensity factors of fretting cracks for a number of pad geometries. The pad geometry is represented by the radius of its rounded corners and the width of its central flat part. The distribution of dislocation method is employed to calculate the stress intensity factors of fretting induced cracks of different lengths for different values of geometrical parameters. The results of this study can be insightful for improving the geometrical design of an aero-engine compressor...
A study of the electrophoretic deposition of bioactive glass-chitosan composite coating
, Article Ceramics International ; Volume 38, Issue 1 , January , 2012 , Pages 471-476 ; 02728842 (ISSN) ; Afshar, A ; Sharif University of Technology
2012
Abstract
Bioactive glass is coated on implant's surface to improve corrosion resistance and osseointegration, when placed in the body. Bioactive glass particles were synthesized through a sol-gel process and deposited along with chitosan to form a composite coating on a stainless steel substrate using electrophoretic deposition technique. Stable suspensions of chitosan-bioactive glass were prepared using bioactive glass particles (<1 μm) and 0.5 g/l chitosan solution. The influence of ethanol-water ratio on deposition yield was investigated. For all process conditions, best results were achieved with suspension of 30 vol% water in ethanol-water containing 2 g/l bioactive glass. FTIR studies showed...
Hydrogen failure sensitivity of A516-Gr70 and API 5L-X70 steels in sour environments
, Article Anti-Corrosion Methods and Materials ; Volume 62, Issue 5 , 2015 , Pages 294-300 ; 00035599 (ISSN) ; Dolati, A ; Beidokhti, B ; Sharif University of Technology
Emerald Group Publishing Ltd
2015
Abstract
Purpose – This paper aims to clarify the corrosion behavior of two famous structural steels in sour environment. These steels have a vast application in oil and gas industries. The study aims to find the effect of different concentrations of sour solution on the origin of crack in these steels. Design/methodology/approach – After preparation of specimens, different sour solutions were made using the synthetic brine (according to National Association of Corrosion Engineers [NACE], Technical Committee Report 1D182) and various amounts of Na2 S.9H2 O and CH3 COOH. The polarization test was done by Potansiostat apparatus model Zahner-IM6 at two temperatures, 25°C...
Micro-scale evolution of mechanical properties of glass-ceramic sealant for solid oxide fuel/electrolysis cells
, Article Ceramics International ; 2020 ; Malzbender, J ; Groß Barsnick, S. M ; Abdoli, H ; Kokabi, A. H ; Faghihi Sani, M. A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The structural integrity of the sealant is critical for the reliability of solid oxide cells (SOCs) stacks. In this study, elastic modulus (E), hardness (H) and fracture toughness (KIC) of a rapid crystallizing glass of BaO–CaO–SiO2 system termed “sealant G” are reported as determined using an indentation test method at room temperature. A wide range of indentation loads (1 mN–10 N) was used to investigate the load-dependency of these mechanical properties. Values of 95 ± 12 GPa, 5.8 ± 0.2 GPa and 1.15 ± 0.07 MPa m0.5 were derived for E, H and KIC using the most suitable indentation loads. An application relevant annealing treatment of 500 h at 800 °C does not lead to a significant change of...
Effects of alloying elements and microstructure on the susceptibility of the welded HSLA steel to hydrogen-induced cracking and sulfide stress cracking
, Article Materials Science and Engineering A ; Volume 507, Issue 1-2 , 2009 , Pages 167-173 ; 09215093 (ISSN) ; Dolati, A ; Koukabi, A. H ; Sharif University of Technology
2009
Abstract
Hydrogen-induced cracking (HIC) and sulfide stress cracking (SSC) susceptibility of the submerged arc welded API 5L-X70 pipeline steel with different amounts of titanium at two levels of manganese (1.4% and 2%) were studied. The centerline segregation region (CSR) observed in the X70 pipe steel played an important role in the HIC susceptibility. Increased acicular ferrite content in the microstructure improved HIC resistance and SSC resistance, while bainite and martensite/austenite constituents deteriorated the workability of the welded specimens in sour environments. The 2% Mn-series welds showed higher SSC susceptibility than the 1.4% Mn-series welds due to the higher hardness values of...