Corrosion Of 316L Research Articles

A study on the fretting corrosion of 316L in static lead-bismuth eutectic (LBE): The role of slip amplitude and normal force on damage mechanism at 350 °C

Fretting corrosion of stainless steel in the LBE affects the safety of lead-cooled fast reactors. Slip amplitude and normal load are the main mechanical factors affecting fretting wear behavior. Thus, the damage mechanism of 316L stainless steel at 350 °C LBE influenced by slip amplitude and normal load was investigated by jointly utilizing multiple characterization methods. The results indicate that the normal load and slip amplitude essentially affect the tangential stress and relative sliding value in the contact area, leading to different slip regions and damage mechanisms. In the mixed slip region, the damage mechanism is adhesion and delamination cracks. The increase in tangential stress leads to decrease in relative sliding. The thick wear debris layer attached to the worn surface can protect the substrate from being attacked by the LBE. In the gross slip region, the damage mechanism is abrasive wear and dissolution corrosion. The increase in relative sliding causes more damage and Ni dissolution, leading to the transformation from austenite to ferrite and internal strain, making the substrate more susceptible to damage and increasing the risk of liquid metal embrittlement (LME) of austenitic stainless steel at 350 °C. Accordingly, a model for different damage mechanisms was proposed. These results can provide important information on the fretting damage related to the LBE environment.

Passivity and Pitting Corrosion of 316L in Simulated Concrete Pore Solutions under Marine Environment

Passivity and Pitting Corrosion of 316L in Simulated Concrete Pore Solutions under Marine Environment

Effect of cold rolling on the pitting corrosion of 316L and 304 austenitic stainless steels

Effect of cold rolling on the pitting corrosion of 316L and 304 austenitic stainless steels

Improvement of corrosion resistance and biocompatibility of 316L stainless steel for joint replacement application by Ti-doped and Ti-interlayered DLC films

Titanium was incorporated and interlayered into diamond-like carbon (DLC) films deposited on 316L stainless steel using a filtered cathodic vacuum arc. The local bonding structure, corrosion, and biocompatibility of non-doped DLC (ta-C), Ti-interlayered (ta-C/Ti), Ti-doped (ta-C:Ti), and Ti-doped and Ti-interlayered (ta-C:Ti/Ti) DLC films were thoroughly investigated. ta-C:Ti/Ti (0.55 at.%Ti) exhibited not only the highest corrosion resistance performance, including the lowest corrosion rate (7.34 × 10 −8 mm yr −1 ), the highest pitting potential (1672.97 mV), and the highest polarization resistance (5.97 MΩ cm 2 ), owing to the formation of TiO 2 on its surface, as confirmed by X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy, but also the highest amount of hydroxyapatite , an indicator for biocompatibility, on its surface as determined with Fourier transform infrared spectroscopy and scanning electron microscopy. Two barrier layers, namely, outer and inner layers, were observed in ta-C/Ti and ta-C:Ti/Ti, while only one barrier layer was in ta-C and ta-C:Ti, as demonstrated by electrochemical impedance spectroscopy . Therefore, ta-C:Ti/Ti is an alternative promising DLC film for joint replacement biomaterials . • ta-C:Ti and ta-C:Ti/Ti notably increased sp 2 bonding fractions. • All DLC films notably improved 316L corrosion resistance in PBS + 1 g L −1 of HA. • Ti interlayer enhanced pitting corrosion resistance while Ti dopant increased R p . • ta-C:Ti/Ti exhibited the most corrosion resistance and biocompatibility due to TiO 2 . • TiO 2 manifested as a barrier layer and a preferred site for HAp formation.

Passivation behavior of 316L stainless steel in artificial seawater: effects of pH and dissolved oxygen

PurposeThe purpose of this paper is to investigate the influence of the potential of hydrogen (pH) and dissolved oxygen in artificial seawater on the passivation behavior of 316L stainless steel.Design/methodology/approachThe corrosion behavior was studied by using electrochemical measurements such as electrochemical impedance spectroscopy and polarization curve. The passive films were characterized with X-ray photoelectron spectroscopy.FindingsThe polarization resistance of the passive film decreases as the pH value drops ascribed to the formation of much more point defects. The donor carrier concentration (ND) in the passive film formed in the deaerated condition is lower than that in aerated conditions. Nevertheless, this phenomenon is the opposite when the pH value is 1 due to the significant decrease of Fe oxides/hydroxides coupled with the stable content of Cr oxides/hydroxides species. In addition, the compositional variation of the passive film also leads to the changes of its semiconductor properties from N-type to bipolar type.Originality/valueThis paper shows the variation of polarization resistance, corrosion potential, passive film composition and semiconductor properties with the pH value and dissolved oxygen. The results can serve as references to the further study on crevice corrosion of 316L in seawater.

Study on corrosion failure prevention of expanded solid expandable tubular

The solid expandable tubular (SET), as a casing damaged well repair tool, should resist residual stress and liquid corrosion. The objective of this study is to reveal the SET expansion of mechanical properties and anti-corrosion performance to carry out a feasibility laboratory expansion experiment. The materials used in this study are 20G and 316L. The mechanical properties of the expansion process of materials and the corrosion behavior of the tube in two kinds of the simulated formation water environment are investigated. Scanning electron microscope (SEM)-energy spectrometer (EDS) comparative analysis displays the surface microstructure and corrosion products of the two materials in different corrosive environments. The results show that both SET materials can meet the requirements of 5–1/2in casing subsidy. The corrosion rate of 20G is similar, which is equivalent to reducing the thickness by 0.25 mm every 10 years, and the 316L corrosion rate is about one-fifth of 20G. The corroded surfaces of 20G and N80 are multi-crack brittle scales caused by iron oxidation. The surface of 316L has attachments without apparent corrosion. Compared with the N80 shell material, the corrosion product film of 20G is denser and has better corrosion resistance. The corrosion resistance of 316L SET is the strongest among these three materials and is suitable for harsh right conditions in corrosive environments.

Further insights into the mechanisms involved in the corrosion of 316L(N) austenitic steel in oxygenated liquid sodium at 550 °C

316 L(N) austenitic steel was corroded at 550 °C in liquid sodium containing 200 μg g−1 dissolved oxygen from 242 h to 7704 h. NaCrO2 is formed for all immersion times, O and Na from liquid metal and Cr from steel. The oxidation front is located at the chromite / steel interface and in the steel grain boundaries. M6C carbides (M = Mo and Fe) are also formed, C from liquid sodium. NaCrO2 is dissolved until the saturation of liquid sodium in Cr is reached. The Cr solubility is higher than that of pure Cr due to the presence of dissolved oxygen.

Electrochemical studies on the effect of residual stress on the corrosion of 316L manufactured by selective laser melting

Selective Laser Melting (SLM) and various subsequent stress-relieving treatments were used to obtain 316 L specimens with compressive residual stresses, varying from 15 to 250 MPa. This enabled a study on the effect of residual stress on corrosion of 316 L using electrochemical methods, which is relevant for durability of additively manufactured materials. Overall, compressive stresses in SLM 316 L result in a measurable increase in the pitting potential, accompanied by a decrease in the passive film currents and donor densities. It is proposed that compressive stresses lower the film growth and repassivation kinetics but slightly enhances the pitting resistance of SLM 316 L.

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Systematical corrosion tests of austenitic stainless steel 316L exposed to sewage sludge SCWO (supercritical water oxidation) were conducted in a batch stirred reactor with hydrogen peroxide as oxidant. Experiment conditions such as temperature, oxidation coefficient, pH value, corrosion medium, were chosen mainly keeping in mind the place and environment of reactions (i.e. surrounding transpiring wall). The exposed samples were ultimately analyzed by weight measurement, scanning electron microscopy in conjunction with energy dispersive spectroscopy, and X-ray diffraction analysis. The results show that severe pitting corrosion occurred as the sample was exposed to complicated environments, and different oxides including Fe3O4, FeCr2O4 and MoO3 were found on the sample surface. The corrosion rate at all test conditions (360–450 °C pH = 5.2–10.05, oxidation coefficient of 0–2.0, sewage sludge or its SCWO reactor effluent) was in the range of 0.12–0.66 mm/y, and it increased as temperature and OC increased at supercritical conditions. Moreover, potential corrosion mechanism of 316L in sewage sludge SCWO is proposed, and influences of operating parameters on 316L corrosion properties are summarized. 316L and reactor effluent could be considered as transpiring wall material and transpiring water in sewage sludge SCWO with transpiring wall reactor, respectively.

Corrosion of 316L in liquid tellurium at 551°C

Grade 316L stainless steel was exposed to liquid tellurium at 551°C. Corrosion was rapid, leading to more than 100 μ m loss of steel section in 30 min. The corrosion product was a mixed telluride scale, which thickened according to parabolic kinetics whilst simultaneously dissolving at its outer surface into the liquid tellurium. A mathematical model based on diffusion-controlled scale growth coupled with dissolution at a rate controlled by liquid phase diffusion is shown to describe scaling and dissolution kinetics successfully.

Influence of High-Density electropulsing treatment on the interface corrosion characteristics of 316L steel in Lead-Bismuth eutectic at 823 K

In order to find an effective method to improve the corrosion resistance properties of the candidate structural materials for lead-alloy cooled fast reactors, the 316L steel was treated by high density single elec-tropulsing. And then the interface corrosion characteristics in stagnant lead-bismuth eutectic (LBE) at 823 K for 1000 h were examined. The results show that electropulsing treatment (EPT) has a significant influence on microcosmic appearance and corrosion depth of the corroded specimens. All the specimens were subjected to dissolution corrosion, but EPT with a current density of 1828 A mm-2 can improve obviously the corrosion resistance and reduce the extent of local corrosion of 316L in LBE. In addition, the corrosion depth of the 1828 A mm-2 EPT specimen decreases by 38%, compared with that of the non-EPT specimens.

Comparison of corrosion behaviour and passive film properties of 316L austenitic stainless steel in CO2 and N2 environments

ABSTRACTThis study investigated the susceptibility to pitting corrosion of 316L in CO2 and N2 environments at temperatures from 30 to 80°C in 3 wt-% NaCl at pH 4. Results from cyclic polarisation technique confirm greater pitting susceptibility of 316L in the CO2 environment. Electronic properties and composition of the passive film were identified by electrochemical impedance spectroscopy, Mott–Schottky, and X-ray photoelectron spectroscopy. Increasing temperature negatively affects the passive film stability, and its influences are amplified in the presence of CO2 as compared to N2. In the CO2 environment, the passive film becomes porous with the increasing temperature leading to higher defects (donor/acceptor densities).

Temperature Effects on Stainless Steel 316L Corrosion in the Environment of Sulphuric Acid (H2SO4)

In its application, metal is always in contact with its environment whether air, vapor, water, and other chemicals. During contact, chemical interactions emerge between metals and their respective environments such that the metal surface corrodes. This study aims to determine the corrosion rate of 316L stainless steel sulphuric acid environment (H2SO4) with weight loss and electrochemical methods. The corrosion rate (CR) is value of 316L stainless steel by weight loss method with sulfuric acid (H2SO4) with concentration of 0.5 M. The result obtained in conjunction with the increase of temperature the rate of erosion obtained appears to be larger, with a consecutive 3 hour the temperature of 50°C is 0.27 mg/cm2h, temperature 70°C 0.38 mg/cm2h, and temperature 90 °C 0.52 mg/cm2h. With the electrochemical method, the current value increases by using a C350 potentiostal tool. The higher the current, the longer the time the corrosion rate increases, where the current is at 90 °C with a 10-minute treatment time of 0.0014736 A. The 316L stainless steel in surface metal morphology is shown by using a Scanning Electron Microscope (SEM).

Corrosion characteristics of 316L as transpiring wall material in supercritical water oxidation of sewage sludge

Systematical corrosion tests of austenitic stainless steel 316L exposed to sewage sludge SCWO (supercritical water oxidation) were conducted in a batch stirred reactor with hydrogen peroxide as oxidant. Experiment conditions such as temperature, oxidation coefficient, pH value, corrosion medium, were chosen mainly keeping in mind the place and environment of reactions (i.e. surrounding transpiring wall). The exposed samples were ultimately analyzed by weight measurement, scanning electron microscopy in conjunction with energy dispersive spectroscopy, and X-ray diffraction analysis. The results show that severe pitting corrosion occurred as the sample was exposed to complicated environments, and different oxides including Fe3O4, FeCr2O4 and MoO3 were found on the sample surface. The corrosion rate at all test conditions (360–450 °C pH = 5.2–10.05, oxidation coefficient of 0–2.0, sewage sludge or its SCWO reactor effluent) was in the range of 0.12–0.66 mm/y, and it increased as temperature and OC increased at supercritical conditions. Moreover, potential corrosion mechanism of 316L in sewage sludge SCWO is proposed, and influences of operating parameters on 316L corrosion properties are summarized. 316L and reactor effluent could be considered as transpiring wall material and transpiring water in sewage sludge SCWO with transpiring wall reactor, respectively.

The Effect of Laser Shock Processing on Corrosion Resistance of Stainless Steel AISI 316L

The paper presents the effect of laser shock processing on stainless steel 316L corrosion resistance. The samples were laser welded and mechanical treated using a Nd:YAG laser with a 1064 nm wavelength, and two different pulse density: 900 pulse/cm2 and 1600 pulse/cm2. After the laser shock processing, the samples were subjected to a seawater solution for corrosion testing. The curves obtained were statistically modeled using Stern-Geary equation. One may observe that the corrosion speed of the LSP samples treated with 900 pulse/cm2 is eight times higher than the corrosion speed of the LSP samples treated with 1600 pulse/cm2.

Improving the empirical model for plasma nitrided AISI 316L corrosion resistance based on Mössbauer spectroscopy

Traditional plasma nitriding treatments using temperatures ranging from approximately 650 to 730 K can improve wear, corrosion resistance and surface hardness on stainless steels. The nitrided layer consists of some iron nitrides: the cubic γ′ phase (Fe4N), the hexagonal phase e (Fe2 − 3N) and a nitrogen supersatured solid phase γN. An empirical model is proposed to explain the corrosion resistance of AISI 316L and ASTM F138 nitrided samples based on Mossbauer Spectroscopy results: the larger the ratio between e and γ′ phase fractions of the sample, the better its resistance corrosion is. In this work, this model is examined using some new results of AISI 316L samples, nitrided under the same previous conditions of gas composition and temperature, but at different pressure, for 3, 4 and 5 h. The sample nitrided for 4 h, whose value for e/γ′ is maximum (= 0.73), shows a slightly better response than the other two samples, nitrided for 5 and 3 h (e/γ′ = 0.72 and 0.59, respectively). Moreover, these samples show very similar behavior. Therefore, this set of samples was not suitable to test the empirical model. However, the comparison between the present results of potentiodynamic polarization curves and those obtained previously at 4 and 4.5 torr, could indicated that the corrosion resistance of the sample which only presents the γN phase was the worst of them. Moreover, the empirical model seems not to be ready to explain the response to corrosion and it should be improved including the γN phase.

Dissolution mechanism of 316L in lead–bismuth eutectic at 500 °C

In the frame of the Accelerator Driven System (ADS) cooled by liquid lead–bismuth eutectic (LBE), the austenitic stainless steel 316L is considered as a possible structural material for the reactor. However, the corrosion of 316L in this liquid alloy environment can be substantial, especially when a dissolution process occurs. In order to understand the dissolution process and to obtain a modelling of the 316L corrosion rate by LBE, an experimental dissolution kinetics of 316L is carried out in stagnant LBE at 500 °C up to 3000 h. A Ni preferential dissolution of the 316L is observed, leading to the formation of a ferritic layer at the 316L surface. A discussion on the various steps occurring in dissolution process leads to the conclusion that only the Ni dissolution reaction rate can control the 316L dissolution kinetics. The dissolution reaction rate constant, k d, calculated from this study experimental points is equal to 4.2 × 10 −11 mol cm −2 s −1.

Analysis of Failure of 316L Heat Exchanger in a Producing Glycine Process Using Hydantoin Method

In this work, analysis was performed to investigate the reasons resulting in corrosion of 316L of heat exchanger tube in the producing glycine process. Results demonstrated that corrosion of 316L is attributed to intergranular corrosion of nonsensitized. Intergranular corrosion of nonsensitized occurs of 316L, the elements of Si, Ni, Mo are clustering, and the carbon oxide increases corrosion.

Biofouling and corrosion of stainless steels in natural waters

The noble shift in corrosion potential to values between +300 and +400 mVSCE and the accompanying increase in cathodic current density and polarization slope at mild cathodic potentials that develop during microbial colonization of passive metals, are collectively known as ennoblement. This phenomenon is of concern as the noble shift in the corrosion potential may lead to pitting corrosion. We have demonstrated, by growing pure cultures of manganese oxidizing bacteria (MOB) Leptothrix discophora SP-6 under well defined conditions, that microbial deposition of manganese oxides causes ennoblement of 316L stainless steel (SS). Exposing 316L corrosion coupons in lakes and streams supported this conclusion; the rate and extent of ennoblement were positively correlated with the rates of deposition and the amounts of biomineralized manganese oxides deposited on the surfaces of the SS corrosion coupons. X-ray photoelectron spectroscopy (XPS) analyses of the deposits from the ennobled coupons revealed a mixture of manganese oxides, as expected. Many natural waters can support growth of MOB. When manganese-oxidizing biofilms accumulate on surfaces of passive metals there is a potential for manganese redox cycling on the metal surface. This process is initiated by depositing minute amounts of manganese oxides on the metal surface. These microbially deposited manganese oxides are then reduced by the electrons derived from anodic dissolution of the metal; the metal is corroding and the manganese oxides are reduced to divalent manganese ions. However, since the manganese ions are liberated within the manganese-oxidizing biofilm, the manganese ions are immediately reoxidized, and the cycle continues.

The influence of surface condition on the localized corrosion of 316L stainless steel orthopaedic implants.

The localized corrosion of austenitic stainless steel 316L intended for use as orthopaedic implants is determined as a function of the surface condition and metallurgical state. From the examination of samples exposed to a ferric chloride solution, at both 22 and 37 degrees C, the independent contribution of crevice and pitting corrosion to localized corrosion is determined. Both forms of localized corrosion occur to a greater extent at the higher temperature. The results indicate that weight loss measurements may not be sufficient to determine the extent of crevice corrosion separately from the influence of pitting corrosion. More importantly, the surface conditions required for the best resistance to crevice or pitting corrosion differ. Electropolished surfaces provide the best resistance to crevice corrosion, while "bead blasted" surfaces provide the best resistance to pitting corrosion. The implication of this result in terms of the serviceability as orthopaedic implants is discussed. The current results indicate the cold-worked state exhibits improved resistance to pitting corrosion. However, the influence of the metallurgical state could not be separated from a possible compositional effect.