Investigation of hydrogen embrittlement failure in a steam separator by field metallography

Pardal, Juan Manuel; Tavares, Sérgio Souto Maior; Barbosa, B.A.R.S.; Mainier, Fernando B.; Corte, J.S.; Pardal, J.P.

doi:10.1016/j.engfailanal.2012.11.001

Cited by 7 publications

(2 citation statements)

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“…Another example is the field metallography by replica, which is a variant of conventional metallography, where it is possible to perform deleterious phases characterization. 34,35 Unfortunately, this technique has disadvantages, such as the need of a professional with high training and qualification, demanding a high time of preparation, execution and taking into account a limit of detection higher than conventional metallography. 36 An alternative, not yet mentioned, is the use of electrochemical techniques (e.g.…”

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confidence: 99%

Sigma and Chi Phases Analysis in UNS S32750 Superduplex Stainless Steel by Optimized Linear Sweep Voltammetry in Alkaline Medium

Sampaio

Furtado

Tavares

et al. 2020

J. Electrochem. Soc.

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Linear sweep voltammetry (LSV) test parameters in alkaline medium were optimized by Doehlert matrix design in order to quantify the deleterious phases in a superduplex stainless steel UNS S32750. The microstructural analysis was performed, in several heat treated specimens, by Light Optical (LOM) and Scanning Electron (SEM) Microscopies and correlated with the electrochemical tests. In these tests, optimized parameters were obtained for tests in aqueous solutions of KOH. The concentration of 3.55 mol l −1 , scan rate of 3.42 mV s −1 and initial potential of −0.818 V, showed a good correlation between the deleterious phases precipitated and charge density values. Differently from LOM characterization, chi and sigma deleterious phases can be distinguished by LSV optimized test. Finally, this test can be a non-destructive powerful tool of quality control to detect embrittlement and corrosion resistance decay that commonly affected this stainless steel as consequence of inadequate fabrication processes.

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confidence: 99%

Sigma and Chi Phases Analysis in UNS S32750 Superduplex Stainless Steel by Optimized Linear Sweep Voltammetry in Alkaline Medium

Sampaio

Furtado

Tavares

et al. 2020

J. Electrochem. Soc.

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“…Hydrogen is supplied by materials in the electrode coating, in the flux or in the shielding gas, as well as by the moist environment (Dayal & Parvathavarthini). This hydrogen insertion added to the usual presence of residual stresses in the weld frequently causes Hydrogen Assisted Cracking (Pardal et al, 2013).…”

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confidence: 99%

Numerical models for simulating hydrogen diffusion and embrittlement in high strength steels

Portugal¹

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This thesis presents and discusses hydrogen diffusion modelling as a first step in predicting and mitigating hydrogen-assisted fracture. Hydrogen embrittlement is a common phenomenon that degrades metals and alloys, and related failures are usual in industry.However, the relationship between hydrogen and the transition from ductile to brittle modes of fracture is not entirely clear. Even though mechanism operating at nano and microscalesare not yet completely understood, it has been proved that embrittlement is proportional to hydrogen concentration within a metal. Therefore, the present work has the objective of establishing, validating, implementing and analysing a consistent numerical model for hydrogen diffusion, in a Continuum Mechanics framework by means of a Finite Element software.Diffusion phenomena are reviewed and particularised on hydrogen transport in metals. In particular, a "two-level" model, considering trapping effects explicitly, is chosen in order to simulate hydrogen diffusion near a crack tip. Strain and stress fields present in a crack or notch are connected with hydrogen diffusion; additionally, hydrogen promotes a local softening, a dilatation and a reduction in cohesive energy so a coupled behaviour between diffusion, elasto-plasticity and damage must be considered.Finally, numerical models for diffusion are applied to fracture modelling in a Cohesive Zone Model approach and a notched tensile test is simulated, demonstrating that the combination of diffusion with damage models might predict brittle fracture. Vessels storing hydrogen are also simulated with the purpose of finding hydrogen distributions near stress concentrators; influence of cyclic loads and compressive residual stresses is also evaluated in these deposits.

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Investigation of Hydrogen Embrittlement Susceptibility of X80 Weld Joints by Thermal Simulation

Peng

Zheng

et al. 2018

J. of Materi Eng and Perform

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Investigation of hydrogen embrittlement failure in a steam separator by field metallography

Cited by 7 publications

References 1 publication

Sigma and Chi Phases Analysis in UNS S32750 Superduplex Stainless Steel by Optimized Linear Sweep Voltammetry in Alkaline Medium

Sigma and Chi Phases Analysis in UNS S32750 Superduplex Stainless Steel by Optimized Linear Sweep Voltammetry in Alkaline Medium

Numerical models for simulating hydrogen diffusion and embrittlement in high strength steels

Investigation of Hydrogen Embrittlement Susceptibility of X80 Weld Joints by Thermal Simulation

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