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Article
Publication date: 20 August 2019

Xiaoxiao Liu and Ming Liu

Corrosion is one of the common damage mechanisms in many engineering structures such as marine structures, petroleum pipelines, aerospace and nuclear reactor. However, the…

Abstract

Purpose

Corrosion is one of the common damage mechanisms in many engineering structures such as marine structures, petroleum pipelines, aerospace and nuclear reactor. However, the service performance of metal materials and structures is gradually degenerating with the increase of service life due to the rapid growth of corrosion damages. Thus, the coupled effects for corrosion damage in reliability analysis should be considered urgently. Then, the purpose of this paper is to develop the corrosion damage physical model and the corresponding reliability analysis methods, which consider the coupled effect of corrosion damage.

Design/methodology/approach

A failure physical model, considering the coupled effect of pitting growth, crack and crack propagation, is presented in this paper. Sequentially, the corrosion reliability with respect to pitting physical damage can be investigated. The presented pitting damage physical model is formulated as time-variant performance limit state functions, which include the crack transition, crack growth and fracture failure mechanics. The first-passage failure criterion is used to construct the corrosion reliability framework, involving in the pitting damage model with the increase of service life.

Findings

Results demonstrate that the multiplicative dimensional reduction (MDR) method behaves much better than FORM no matter in accuracy or efficiency. The proposed corrosion reliability method is applicable for dealing with the damage failure model of the structural pitting corrosion.

Originality/value

The MDR method is used to calculate the corrosion reliability index of a given structure with fewer function calls. Finally, an aeronautical metal material is used to demonstrate the efficiency and precision of the proposed corrosion reliability method when the failure physical model considering the coupled effects of mechanical stresses and corrosion environment is adopted.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 10 October 2016

Subir Paul

The purpose of this paper is to predict the life of a corroding metallic structure in seawater so that uncertain and unpredictable failures of a structure, leading to…

Abstract

Purpose

The purpose of this paper is to predict the life of a corroding metallic structure in seawater so that uncertain and unpredictable failures of a structure, leading to accidents, can be prevented.

Design/methodology/approach

Pitting has been known to show a large scatter in the measurable parameters such as corrosion rate, maximum pit depth, time to perforation and so on. Scatter results from the influence on pit development on metal surface heterogeneity and from variations in the corrosive environment over time. All these facts suggest that randomness is an inherent and unavoidable characteristic of pitting corrosion over time, so that stochastic models have been developed to formulate pit depth as a function of parameters influencing the process. Since chloride penetrates the passive film of the metal surface, Cl ion distribution into the metal has been mapped by finite element method (FEM).

Findings

The maximum pit depth which decides the onset of perforation or leakage has been modeled by the following equation: d=36.31(ΔE)0.68×(Δt)0.35. Cl ion distribution within a pit and outside has been modeled for better understanding of pit initiation which till today is not fully understood.

Practical implications

Perforation and leakage of a tank, container, or pipeline occur when the depth of pitting reaches the section thickness of the material of which the metallic structures are made. The pitting corrosion is localized and occurs at any spot or site where electrochemical conditions (ΔE Equation (9)) are prone to pitting. This leads to unpredictable failures of the structures which may look polished and undamaged under naked eyes. In most metallic structures, pitting may be present at some spots, but failures occur only when the depth predicted by the model Equation (9) reaches the section thickness of the material. Thus, determining pipe to soil potential gives a guide to go for maintenance before pit depth reaches the material thickness, and thereby unpredictable failure can be prevented. Second, the map generated by FEM showing Cl distribution throws much information and light on movement of Cl ions from passive layer into the pit, which leads to its growth. This helps scientists and researchers to understand the mechanism and gives much insights on finding new methods for protection of structures.

Social implications

The work will guide the engineers and researchers to prevent unpredictable failures of structures leading to accidents and human and property loss and prevent environment pollution from spilling of oil from tank and pipeline.

Originality/value

This is an original work based on several laboratory-generated simulated experimental data.

Details

Multidiscipline Modeling in Materials and Structures, vol. 12 no. 3
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 8 September 2012

J. González‐Sánchez, L. Dzib‐Pérez, E. Garcia‐Ochoa, G. Canto and M. Sosa‐Baz

The purpose of this paper is to quantitatively assess the pit growth rate on AISI 304L and AISI 316 austenitic stainless steels in natural seawater and 3.5 wt.% NaCl…

Abstract

Purpose

The purpose of this paper is to quantitatively assess the pit growth rate on AISI 304L and AISI 316 austenitic stainless steels in natural seawater and 3.5 wt.% NaCl solutions through electrochemical measurements during the potentiostatic growth of pits.

Design/methodology/approach

A quantitative characterisation was carried out based on chronoamperometric measurements. The volume of dissolved metal per pit was calculated from the charge registered and Faraday's law, considering both, hemispherical and semi‐elliptical pit shapes and the density of the steels. Empirical growth laws for maximum pit depth as a function of polarisation time were obtained and compared with pits volumetric profile obtained from optical microscopy analysis and mechanical removal of material on both steels.

Findings

Electrochemical‐based calculations of localised metal dissolution per pit present acceptable fit with the real volume of dissolved metal on hemispherical pits.

Originality/value

The paper presents the quantitative relationship of the corrosion pit growth rate of stainless steels in chloride containing solution determined by chronoamperometry (electrochemical technique) through the Faraday law's, with the mechanical removal of material (pit profile) through the density of metal.

Details

Anti-Corrosion Methods and Materials, vol. 59 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 7 November 2016

Somrerk Chandra-ambhorn, Wisarut Wachirasiri and Gobboon Lothongkum

This paper aims to construct the E-pH diagrams for AISI 316L stainless steel in chloride solutions containing SO42− ions and therefore investigate the role of SO42− ions…

Abstract

Purpose

This paper aims to construct the E-pH diagrams for AISI 316L stainless steel in chloride solutions containing SO42− ions and therefore investigate the role of SO42− ions on pitting corrosion of stainless steel.

Design/methodology/approach

A cyclic potentiodynamic polarisation method was performed to obtain polarisation curves at different pH. From these curves, corrosion, primary passivation, pitting and repassivation potentials were determined and plotted as a function of pH giving the E-pH diagram.

Findings

The addition of SO42− ions to 10,650 ppm NaCl solution up to 3,000 ppm widened the passivation regime of the E-pH diagram mainly by shifting the pitting corrosion potential to the noble direction. This indicated the inhibiting role of SO42− on the nucleation of new pits in the transpassive region. It also stabilised the pitting corrosion potential at the pH ranging from 5 to 11. However, at pH 7, it caused the pit area to increase, implying the catalytic role of SO42− on the pit growth. Finally, it did not change the types of ions dissolved in solutions after pitting.

Practical implications

The diagrams can be used as a guideline in industries to determine the passivation regime of the AISI 316L stainless steel in chloride- and sulphate-containing solutions.

Originality/value

This paper reported the E-pH diagrams for the AISI 316L stainless steel in chloride solutions containing SO42− ions. The roles of pH and SO42− ions on pitting corrosion were innovatively discussed using a point defect model.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 5 June 2020

Minjie Zhang, Ronghai Xu, Lele Liu, Sensen Xin and Moucheng Li

The purpose of this paper is to investigate the electrochemical corrosion behavior of type 444 stainless steel (SS) in synthetic tap water from 25°C to 80°C, i.e. the…

Abstract

Purpose

The purpose of this paper is to investigate the electrochemical corrosion behavior of type 444 stainless steel (SS) in synthetic tap water from 25°C to 80°C, i.e. the operation environment of the electric water heater.

Design/methodology/approach

The corrosion behavior was studied by using electrochemical measurements such as electrochemical impedance spectroscopy and polarization curve. The specimen surfaces were observed with scanning electron microscopy. The passive films were characterized with X-ray photoelectron spectroscopy.

Findings

In the typical tap water, 444 SS passivates spontaneously under different temperatures. The passive films formed at higher temperatures contain relatively less Cr-species and more Cl ions, resulting in lower polarization resistances. The stable pitting corrosion takes place in the potential region of oxygen evolution as the temperature increases to about 55°C. The critical Cl concentration of pitting corrosion reduces from about 160 mg L−1 to 60 mg L−1 with changing temperature from 25°C to 80°C.

Practical implications

The pitting corrosion probability was assessed through the statistical analysis of tap water quality. The results are useful for the application of 444 SS as well as the design of electric water heater.

Originality/value

This paper shows the variation of polarization resistance, pitting potential, passive film composition and critical pitting chloride concentration with the temperature of tap water. It is of great significance for the development and application of SS in tap water environments.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 28 October 2014

J.L. Li, C.T. Qu, S.D. Zhu, L. Liu and Z.Q. Gao

The purpose of this study was to investigate the pitting resistance and assess the critical pitting temperature (CPT) of a super martensitic stainless steel, 00Cr13Ni5Mo2…

Abstract

Purpose

The purpose of this study was to investigate the pitting resistance and assess the critical pitting temperature (CPT) of a super martensitic stainless steel, 00Cr13Ni5Mo2, made in China, considering especially the difference in the pitting corrosion resistance between the domestic super martensitic stainless steel and an imported one.

Design/methodology/approach

Potentiodynamic sweep tests were applied to investigate the effects of four NaCl concentrations (weight per cent) of 1, 3.5, 9 and 17, and four testing temperatures of 30, 50, 75 and 90°C on the pitting resistance of the domestic super martensitic stainless steel in the presence of CO2. Potentiostatic sweep tests were utilized to determine the CPT. Furthermore, chemical immersion exposures, implemented according to the appropriate standard were used to evaluate the difference in the pitting corrosion resistance between the domestic super martensitic stainless steel and an imported one. In addition, the morphology of pits was analyzed using a scanning electron microscope.

Finding

The pitting potential of the domestic super martensitic stainless steel decreased with an increase in NaCl concentration and temperature in the presence of CO2. The CPT of the domestic super martensitic stainless steel measured by potentiostatic polarization was 41.16°C. Two types of typical corrosion pits, closed pits formed at 35°C and open pits formed at 50°C, were observed. Furthermore, compared to the super martensitic stainless steel made in Japan, the domestic one was better in terms of pitting potential, corrosion rate and the density of the pits, but worse in terms of the depth of the pits, which may result in a risk of corrosion perforation of tubing and casings.

Originality/value

The paper highlights that chloride ions, temperature and the presence of CO2 play an important role on the pitting resistance of super martensitic stainless steel.

Details

Anti-Corrosion Methods and Materials, vol. 61 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 6 March 2017

A. Yilmaz

Pitting inhibition efficiency of SO4 and NO3 on AISI 316L stainless steel in contact with Cl-containing fiber dyeing solutions together with the influence of the anions…

Abstract

Purpose

Pitting inhibition efficiency of SO4 and NO3 on AISI 316L stainless steel in contact with Cl-containing fiber dyeing solutions together with the influence of the anions on absorption behavior of the solutions were investigated. The purpose of the study is to experimentally determine an optimized dyeing solution efficient on both – inhibition of the steel’s pitting and exhaustion of the dyes dissolved.

Design/methodology/approach

Methods such as electrochemical cyclic polarization, UV-visible range spectrophotometry and scanning electron microscopy have been used to assess the performance of two inhibitors on both pitting inhibition of the steel and dissolving ability over the reactive dyes. To find out a promising dyeing solution mixture in both aspects, Cl content of the original dyeing solution was replaced gradually with the inhibiting anions, where the total anionic content was kept constant to unchange the dye exhaustion potential of the solution. Then, those solutions came out with diverse pitting inhibition, and dye absorption levels were compared together for reducing/avoiding the pitting issues of the reactive dyeing vessels of the industry.

Findings

Rather high absorption levels detected by visible range spectrophotometry on the solutions showing sound inhibition levels indicated possibility of unaltered reactive dyeing qualities with an enhanced vessel lifetime as the inhibitive anions replace Cl. Nitrate performed better than sulfate both on inhibition and absorption in the dyeing solutions. Also, 316L vessels became open to an extra anodic protection in inhibitor added solutions.

Research limitations/implications

The findings are valid for a certain group of reactive dyes and dyeing solutions held at 70°C. However, the testing methods are available to almost any dyeing solution and dyeing temperature.

Originality/value

The work presents a combined testing of pitting inhibition and absorption behavior of dyeing solutions involving Cl that has not been reported so far. It shows that solution recipes least harmful to the steel vessels can be outlined for various reactive or other types of dye groups.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 9 January 2009

K. Jafarzadeh, T. Shahrabi, S.M.M. Hadavi and M.G. Hosseini

The paper aims to focus on the recognition of corrosion product morphologies of AA5083‐H321 corroding aluminum‐magnesium alloys used in the manufacture of aluminum high…

Abstract

Purpose

The paper aims to focus on the recognition of corrosion product morphologies of AA5083‐H321 corroding aluminum‐magnesium alloys used in the manufacture of aluminum high speed boats and submarines during flow induced corrosion in seawater.

Design/methodology/approach

All experiments were conducted in a 3.5 percent NaCl solution as the simulated marine environment. Hydrodynamic conditions were created by an rotating cylinder electrode (RCE) system. Morphological characterization of the surface was undertaken using SEM and EDAX techniques. Cyclic polarization tests were used to determine the electrochemical behavior of the alloy.

Findings

The results obtained reveal that the pit density on the sample surface increased with increasing the rotation speed. The enhanced flow condition also enhanced the tendency for intermetallic particles, including submicron size Al(Mg,Mn) inclusions, to promote pitting corrosion of the alloy. An interesting result was that crystallographic pitting occurred at rotation speeds greater than 5 m/s.

Practical implications

In the selection of corrosion control methods for high speed aluminum‐hulled boats, control of erosion corrosion was determined to be more important than any other form of corrosion.

Originality/value

Provides information about the contribution of mechanical and electrochemical corrosion phenomena in corrosion of high speed aluminum boats under hydrodynamic conditions. Characterization of new intermetallic particles in aluminum‐magnesium alloys that can promote pitting during flow induced corrosion in marine environments. Provides new information about the origin of crystallographic pitting attack on aluminum.

Details

Anti-Corrosion Methods and Materials, vol. 56 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 1 June 2004

S.R.F. Batista and S.E. Kuri

Duplex stainless steels are excellent materials for industrial applications and their use has increased in the oil, chemical, petroleum (offshore), and electric power…

1094

Abstract

Duplex stainless steels are excellent materials for industrial applications and their use has increased in the oil, chemical, petroleum (offshore), and electric power industries. Pitting resistance equivalent (PRE) is the first parameter used to characterise the pitting and crevice corrosion resistance. Nevertheless, there are other aspects to be considered, such as the precise values of the PRE in the α and γ phases and the selective corrosion processes that may occur at grain boundaries. This paper indicates that α/γ and α/σ interfaces are preferential sites for the nucleation and growth of pits and for consequent selective corrosion, with increasing tendency in the ferritic phase. In addition, the selective dissolution potential is more reactive (and therefore, is of greater significance) than the pitting potential.

Details

Anti-Corrosion Methods and Materials, vol. 51 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 5 September 2018

Byung-Hyun Shin, Junghyun Park, Jongbae Jeon, Sung-bo Heo and Wonsub Chung

In this study, super duplex stainless steel (SDSS) was heat-treated. The purpose of this study is to assess the effect of the cooling rate after heat treatment on the…

Abstract

Purpose

In this study, super duplex stainless steel (SDSS) was heat-treated. The purpose of this study is to assess the effect of the cooling rate after heat treatment on the pitting corrosion of SDSS.

Design/methodology/approach

The heat treatment from 1,000°C to 1,300°C was applied to SDSS to check the effect of the cooling rate.

Findings

The heat treatment temperature produced a different SDSS microstructure, and the cooling rate led to the growth of austenite. The casted SDSS indicated the presence of heterogeneous austenite, and the precipitation secondary phase under 1.6 per cent precipitated to bare metal. By applying heat treatment and cooling SDSS, its corrosion resistance changes because of the change in the chemical composition. The cooling rate at 5,600 J/s has the highest critical pitting temperature (CPT) at 1,100°C, and the cooling rate at 1.6 J/s has the highest CPT at 1,200°C. Low cooling rate (0.4 J/s) made the secondary phase at all temperature range.

Research limitations/implications

The effect of secondary phase not consider because that is well known to decreasing corrosion resistance.

Practical implications

Solution annealing is taken into account to optimize the corrosion resistance. But that is not consider the cooling rate at each temperature. This study assessed the effect of the cooling rate at each temperature point.

Social implications

Manufacturers need to know the effect of the cooling rate to optimize the corrosion resistance, and this study can be applied in the industrial scene.

Originality/value

SDSS is hard the optimization because SDSS is a dual-phase stainless steel. Corrosion resistance can be optimized by controlling heat treatment temperature and the cooling rate. Anyone not studied the effect of the cooling rate at each temperature. The effect of the cooling rate should be considered to optimize the corrosion resistance.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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