Blar i NTNU Open på forfatter "Johnsen, Roy"
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Hydrogen Induced Stress Cracking susceptibility of strain-hardened Ni alloys Sanicro 35 and Alloy 750 HS
Eiesland, Solfrid (Master thesis, 2023)I dette arbeidet er mottakeligheten for hydrogenindusert sprekking (HISC) blitt undersøkt og sammenlignet for to arbeidsherdede nikkelbaserte legeringer, Sanicro 35 (UNS N08935) og høystyrket P750 (DIN nr. 1.4675). Dette ... -
Hydrogen stress cracking and crack initiation in precipitation hardened Ni-alloys
Stenerud, Gaute; Johnsen, Roy; Olsen, Jim Stian (Journal article; Peer reviewed, 2018)The two different precipitation hardened nickel alloys, Alloy 718 and Alloy 725, were tested in its as received condition. Their susceptibility to hydrogen stress cracking was examined by the use of stepwise increasing ... -
Hydrogen uptake and diffusivity in steel armor wires with different chemical composition, carbide distribution, grain size, and degree of deformation
Skilbred, Ellen Synnøve; Kappes, Mariano; Iannuzzi, Mariano; Johnsen, Roy (Peer reviewed; Journal article, 2021)In this study, six flexible pipe steel armor wires used in oil and gas transportation are characterized, and their hydrogen diffusion coefficients and hydrogen uptakes are measured using an electrochemical hydrogen permeation ... -
Hydrogen uptake during active CO2-H2S corrosion of carbon steel wires in simulated annulus fluid
Skilbred, Ellen Synnøve; Palencsar, Simona; Dugstad, Arne; Johnsen, Roy (Peer reviewed; Journal article, 2022)The hydrogen uptake of five carbon steel wires exposed to a corrosive CO2/H2S environment where protective film formation was not favorable was measured. The hydrogen uptakes decreased with the accumulation of retained ... -
Hydrogen-Assisted Cracking Investigated by In Situ Electrochemical Micro-Cantilever Bending Test
Hajilou, Tarlan (Doctoral theses at NTNU;2018:212, Doctoral thesis, 2018)Most high strength and high performance alloys experience a premature rupture and loss in the ductility when exposed to hydrogen. The interaction of hydrogen with dislocations and other microstructural defects such as ... -
Hydrogen-induced degradation behavior of nickel alloy 625, studied using multiscale in-situ experiments
Soundararajan, Chandrahaasan Kattuputhur (Doctoral theses at NTNU;2023:435, Doctoral thesis, 2023)Nickel-based alloys are widely used in the oil and gas industries as safety critical components owing to its high strength and corrosion resistance properties. However, they are susceptible to hydrogen embrittlement (HE), ... -
Impressed current system for internal corrosion protection in monopiles for offshore windmills: Investigation of the calcareous deposits formation mechanism and behaviour in confined and partially open compartments
Cherif, Osema (Master thesis, 2022)Impressed current cathodic protection (ICCP) is a highly effective corrosion protection system for submerged structures. When polarising the steel to its immune state by applying a protective current, the interfacial pH ... -
In situ small-scale hydrogen embrittlement testing made easy: An electrolyte for preserving surface integrity at nano-scale during hydrogen charging
Hajilou, Tarlan; Hope, Malin S.B.; Hossein Zavieh, Amin; Kheradmand, Nousha; Johnsen, Roy; Barnoush, Afrooz (Journal article; Peer reviewed, 2018)An electrolyte for electrochemical hydrogen charging of corrosion-susceptible alloys is developed, which preserves the surface integrity at nano-scale by minimizing the surface roughness alternation. To assure the formation ... -
Influence of calcareous deposits on hydrogen uptake in 13% Cr super martensitic stainless steel under cathodic protection
Smirnova, Anna; Johnsen, Roy; Nisancioglu, Kemal (Chapter, 2010) -
Influence of Manufacturing Process and Resulting Microstructure on HISC Susceptibility of 25Cr Duplex Stainless Steel Pipe
Johnsen, Roy; Heimssæther, Martin; Gjelseng, Linn; Qvale, Atle H; Jernberg, Anders (Journal article; Peer reviewed, 2019)Due to its attractive combination of strength corrosion resistance and cost 25% Cr Duplex Stainless Steel Pipe is used extensively in subsea production systems. Pipes are made by different production methods. The various ... -
Influence of tungsten on passivity breakdown and repassivation of 25CR super duplex stainless steel
Torres Rodriguez, Cristian; Kappes, Mariano A; Johnsen, Roy; Iannuzzi, Mariano (Journal article; Peer reviewed, 2018)Super duplex stainless steels are ferritic-austenitic stainless steels with 25 wt% Cr and a pitting resistance equivalent (PRE) ≥ 40. Even though other elements, such as Cr and Mo, have been studied in much more detail ... -
Integrated cathodic protection (CP) sensor network development of the CP sensor
Wold, Kristian; Johnsen, Roy; Iannuzzi, Mariano; Årtun, Lars (Journal article; Peer reviewed, 2018)This paper describes a new CP monitoring approach to quantify the health of the CP system in real-time with spatial resolution. Spatial resolution is achieved by an integrated sensor network distributed across a Subsea ... -
Integrity Evaluation of Duplex Stainless Steel Flanges
Sture, Henrik (Master thesis, 2012)Duplex stainless steel flanges are normally forged to form, as required by the ASTM A182/A182M standard, but may also potentially be machined directly from forged stainless steel bar. In order to evaluate the integrity of ... -
Integrity of Nickel Alloys used for Subsea Applications
Stenerud, Gaute (Doctoral theses at NTNU;2018:287, Doctoral thesis, 2018) -
Investigation of hydrogen embrittlement behavior in X65 pipeline steel under different hydrogen charging conditions
Wang, Dong; Hagen, Anette Brocks; Undrum Fathi, Pernille; Lin, Meichao; Johnsen, Roy; Lu, Xu (Journal article; Peer reviewed, 2022)The hydrogen effect on a X65 carbon steel was investigated by tensile tests under both ex-situ and in-situ hydrogen charging conditions. The fractured samples were characterized and compared using a combination of scanning ... -
Korrosjon av Stål i Ferskvann
Bengtsson Blucher, Daniel; Knudsen, Ole Øystein; Brakstad, Odd Gunnar; Hakvåg, Sigrid; Johnsen, Roy (Research report, 2022)Det er i dag en diskusjon gående om korrosjon og korrosjonsmonn på pæler som skal stå i Mjøsa. Mjøsa er ferskvann, og det gjelder pæler på lengder opp mot 100 meter, og ca 50 meter av pælen vil stå i ferskvannet. Det er ... -
Korrosjon i inntaksrørene for brannvann på St. Olavs Hospital - undersøkelse, omfang og årsak
Parow, Hanna (Master thesis, 2018)For rørsystemer i stål er tiltetning og lekkasjer forårsaket av korrosjon et av hovedproblemene for vedlikehold og drift av vannbaserte brannvernsystemer. Reparasjon av korrosjonsskader på grunn av mekanisk svikt gir ... -
Korrosjon og Tribologi Effekter på Belegg for Uttrekkbare Baug Foiler for Skip
Fidje, Connie Iren Senland (Master thesis, 2019)Hydrofoiler har lenge blitt brukt på mindre båter. Men som følge av forskjellige utfordringer, har det ikke til nå vært mulig å bruke foiler på større farttøy. Wavefoil er et firma som har utviklet en uttrekkbar foliemodul ... -
Microstructural characterization of pulsed plasma nitrided 316L stainless steel
Asgari, Masoud; Barnoush, Afrooz; Johnsen, Roy; Hoel, Rune (Journal article; Peer reviewed, 2011) -
Modeling of Hydrogen Diffusion in 25% Cr Super Duplex Stainless Steel
Jemblie, Lise (Master thesis, 2012)Over the last years, several failures in duplex and super duplex stainless steel structures in subsea applications are reported to be a result of hydrogen induced stress cracking. One main source of hydrogen is found to ...