Flow accelerated corrosion and erosion−corrosion behavior of marine carbon steel in natural seawater

AbstractIn this work, flow accelerated corrosion (FAC) and erosion−corrosion of marine carbon steel in natural seawater were electrochemically studied using a submerged impingement jet system. Results show that the formation of a relatively compact rust layer in flowing natural seawater would lead to the FAC pattern change from ‘flow marks’ to pits. The increase of the flow velocity was found to have a negligible influence on the FAC rate at velocities of 5−8 m s−1. The synergy of mechanical erosion and electrochemical corrosion is the main contributor to the total steel loss under erosion−corrosion. The increase of the sand impact energy could induce the pitting damage and accelerate the steel degradation. The accumulation of the rust inside the pits could facilitate the longitudinal growth of the pits, however, the accumulated rusts retard the erosion of the pit bottom. The erosion and corrosion could work together to cause the steel peeling at the pit boundary. The steel degradation would gradually change from corrosion-dominated to erosion-dominated along with the impact energy increasing.

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Wall-Thinning Analysis of the Pipelines in the Secondary Section of NPP

Volume 1: Plant Operations, Maintenance, Engineering, Modifications, Life Cycle and Balance of Plant; Nuclear Fuel and Materials; Radiation Protection and Nuclear Technology Applications ◽

10.1115/icone21-15076 ◽

2013 ◽

Author(s):

Na Ma ◽

Li Wang ◽

Jinguang Qin

Keyword(s):

Carbon Steel ◽

Nuclear Power ◽

Power Plants ◽

Xrd Analysis ◽

Operating Conditions ◽

Chemical Compositions ◽

Accelerated Corrosion ◽

Wall Thinning ◽

Erosion Corrosion ◽

Flow Accelerated Corrosion

Wall-thinning investigation of three carbon steel pipe samples from secondary section of nuclear power plants has been carried out in this paper. The operating conditions of the three pipe samples are quite different, which leads to the different wall-thinning reasons and characteristics of the pipes. The chemical compositions of the steel materials, the stereomicroscope examinations, SEM examinations, as well as the XRD analysis are performed. The results show that: The wall-thinning of No.1 elbow was caused by erosion corrosion; the wall-thinning of No.2 elbow was caused by flow accelerated corrosion; the wall-thinning and crevasse of No.3 orifice plate was caused by cavitations. Measures to solve the wall-thinning problems of different pipes are also given in this paper.

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Comparative Study on Flow-Accelerated Corrosion and Erosion–Corrosion at a 90° Carbon Steel Bend

Materials ◽

10.3390/ma13071780 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1780 ◽

Cited By ~ 11

Author(s):

Li Zeng ◽

Geng Chen ◽

Hanxin Chen

Keyword(s):

Carbon Steel ◽

Comparative Study ◽

Surface Analysis ◽

Electrochemical Measurements ◽

Accelerated Corrosion ◽

Corrosion Rates ◽

Erosion Corrosion ◽

Flow Accelerated Corrosion ◽

Inside Wall

Electrochemical measurements and surface analysis are performed to comparatively study flow-accelerated corrosion (FAC) and erosion–corrosion (E-C) behavior at a 90° carbon steel bend. The corrosion rates are higher under FAC conditions than those under E-C conditions. For FAC, the corrosion is more serious at the inside wall. However, corrosion is exacerbated at the outside wall under E-C conditions. No erosion scratches are observed under FAC conditions and at the inside wall under E-C conditions, while remarkable erosion scratches appear at the outside wall under E-C conditions. The dominant hydrodynamics affecting FAC and E-C are remarkably different.

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Analytical Investigation of Deaerator Steam Inlet Nozzle Corrosion Allowance in a CANDU Station

Volume 2: Structural Integrity; Safety and Security; Advanced Applications of Nuclear Technology; Balance of Plant for Nuclear Applications ◽

10.1115/icone17-75617 ◽

2009 ◽

Author(s):

Ali Keshavarz ◽

Andrew K. Ali ◽

Randy K. Lall

Keyword(s):

Finite Element ◽

Carbon Steel ◽

Stress Analysis ◽

Analytical Investigation ◽

Percentage Error ◽

Metal Loss ◽

Fe Model ◽

Accelerated Corrosion ◽

Materials Properties ◽

Flow Accelerated Corrosion

Flow-accelerated corrosion (FAC) is a phenomenon that results in metal loss from piping, vessels and equipment made of carbon steel. This metal loss can lead to stress to occur at the steam inlet nozzle side, where it is located at the side of the deaerator. This paper presents a method to find the thickness critical of the steam inlet nozzle. A Finite Element (FE) model of the pressure vessel head was created to perform a stress analysis using NX Nastran 5.0. By applying materials properties, loads and constraints to the model, the results obtained are required to satisfy the following criterion: vonMises≥SySy=YieldStrength The results obtained from the stress analysis were analyzed to obtain a corrosion allowance and it was compared to the recommended value from a normal deaerator design, which is roughly 0.25 inches. From the FE model, and by continuously reducing the thickness of the nozzle, it was determined that the corrosion allowance is 0.229 inches, and that the percentage error was 8.4%.

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The impact of flow-accelerated corrosion on the crack developing in welded joints of NPP equipment and pipelines

Industrial laboratory Diagnostics of materials ◽

10.26896/1028-6861-2021-87-3-58-63 ◽

2021 ◽

Vol 87 (3) ◽

pp. 58-63

Author(s):

D. A. Kuz’min

Keyword(s):

Welded Joints ◽

Accelerated Corrosion ◽

Equipment And Pipelines ◽

Flow Accelerated Corrosion ◽

The Impact

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A study of flow accelerated corrosion at elbow of carbon steel pipeline by array electrode and computational fluid dynamics simulation

Corrosion Science ◽

10.1016/j.corsci.2013.08.022 ◽

2013 ◽

Vol 77 ◽

pp. 334-341 ◽

Cited By ~ 51

Author(s):

G.A. Zhang ◽

L. Zeng ◽

H.L. Huang ◽

X.P. Guo

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Carbon Steel ◽

Dynamics Simulation ◽

Computational Fluid Dynamics Simulation ◽

Accelerated Corrosion ◽

Steel Pipeline ◽

Array Electrode ◽

Flow Accelerated Corrosion

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Techniques for Improved Reliability of Wall Thinning Estimation

Volume 6: Materials and Fabrication ◽

10.1115/pvp2006-icpvt-11-93414 ◽

2006 ◽

Author(s):

Yogendra S. Garud

Keyword(s):

The Other ◽

Remaining Life ◽

Data Filtering ◽

Large Database ◽

Accelerated Corrosion ◽

Wall Thinning ◽

Simplified Method ◽

Flow Accelerated Corrosion ◽

The Impact ◽

Thinning Rate

Wall thinning in pressure retaining components, especially due to the flow-accelerated corrosion, has been a significant factor affecting the safety and unplanned system downtimes. On the other hand, overestimating the impact of possible wall thinning often leads to unnecessary or expensive inspections and replacements. The simplified or quick (short-cut) methods of analysis and prediction often lack the requisite degree of accuracy and confidence. This paper presents a few techniques for better analysis of the wall thinning data to address these issues. These techniques make use of the statistical methods, pattern recognition, and optimization to perform a robust data filtering and thinning rate estimation that accounts for measurement uncertainty. The techniques are discussed with application to a large database and an inspection program. The impact of these analytical improvements is presented in comparison with results of the simplified method of analysis. The results include both the margin on remaining life and the projected wall thinning rates, with implications for inspections.

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