Corrosion Of Austenitic Stainless Steel Research Articles

Plastic deformation and corrosion in austenitic stainless steel: A novel approach through microtexture and infrared spectroscopy

The anodic potentiodynamic polarization behaviors of austenitic stainless steels, with varying Cu (copper) and/or Mo (molybdenum) additions, were explored after plane strain compression. Though all the alloys showed developments in deformed microstructures, the presence of Cu+Mo did not result in strain induced martensite formation (SIMF). However, the presence of Cu+Mo revealed the highest degradation in corrosion performance. A combination of microtexture measurements and fourier transform infrared spectroscopy (FTIR)-imaging revealed that the presence of SIMF promoted post-passivation stability or retention of a protective Cr2O3 film.

Application of Ultrasonic Methods for Early Detection of Intergranular Corrosion in Austenitic Stainless Steel

ABSTRACTIntergranular corrosion (IGC) is one of the major localized corrosion problems faced by austenitic stainless steel components in ultra-supercritical power plants, which occurs along the grain boundaries of material and results in loss of engineering properties. Ultrasonic technique was applied to the early detection of IGC in austenitic stainless steel super304H. Acoustic attenuation and nonlinear parameter were measured at multiple excitation frequencies, and an equivalent attenuation factor and an equivalent nonlinear factor were defined to evaluate the IGC damage. Results indicated that both factors increased monotonously as the degree of IGC developed, and the equivalent nonlinear factor is more sensitive to IGC at early stage. Thus they can be utilized for early detection of IGC in austenitic stainless steel.

Effect of nitrate on corrosion of austenitic stainless steel in boiling nitric acid solution containing chromium ions

ABSTRACTThe oxidation behavior of chromium and the corrosion behavior of austenitic stainless steel in boiling nitric acid solution containing highly concentrated nitrates were investigated using UV-visible spectroscopic measurements, Raman spectral measurements, immersion tests, and potentiodynamic polarization measurements. The oxidation rate measurement of chromium from Cr(III) to Cr(VI) was performed by 1 M boiling nitric acid solution containing each highly concentrated nitrates: Al(NO3)3, Nd(NO3)3, Ca(NO3)2, Mg(NO3)2, and NaNO3 as a simulant of uranium nitrate in uranium concentrator in reprocessing plants. As a result, the rate of chromium oxidation was different depending on the added nitrates even at the same nitric acid concentration. In addition, the oxidation rate of chromium was increased with increasing the calculated partial pressure of nitric acid in consideration of the hydration of cation of nitrates. Furthermore, the corrosion rate of type 310 stainless steel was accelerated by the solution having a high chromium oxidation rate containing nitrates. These results indicated that the acceleration of the corrosion rate in the solutions depending on the oxidation rate of chromium, and the rate is affected by the salt-effect of nitrates.

Effect of Post Heated TiN Coating on Pitting Corrosion of Austenitic Stainless Steel

This study used cathodic arc deposition technique to coat TiN film on 316L austenitic stainless steel, and then the coated specimens were heat-treated at the different temperatures. Observation of coating morphology and corrosion tests were conducted for exploring the effect of post-heating temperature on composition, microstructure, and corrosion behavior of the coatings. The results showed when the heating temperature was up to the range of 500-600 oC, a Ti-N-O mixed film consisting of the two TiO2 and TiN phases was formed on the outer layer. Particular, the film heated at 500 oC had a dense structure as well as homogeneous chemical composition. Such the result could effectively inhibit pitting corrosion of 316L stainless steel in 3.5 wt% NaCl and 10 vol% HCl solutions.

Effect of Water Vapor on High-Temperature Corrosion under Conditions Mimicking Biomass Firing

The variable flue gas composition in biomass-fired plants, among other parameters, contributes to the complexity of high-temperature corrosion of materials. Systematic parameter studies are thus necessary to understand the underlying corrosion mechanisms. This paper investigates the effect of water (H2O) vapor content in the flue gas on the high-temperature corrosion of austenitic stainless steel (TP 347H FG) under laboratory conditions, to improve the understanding of corrosion mechanisms. Deposit-coated and deposit-free samples were isothermally exposed for 72 h in a synthetic flue gas atmosphere containing either 3 or 13 vol % H2O vapor. Comprehensive characterization of the corrosion products was carried out by the complementary use of microscopic, spectroscopic, and diffraction-based techniques. To evaluate the effect of the exposure time, results were compared to previous results with longer isothermal exposure over 168 h and indicated that the development of a Ni-rich layer as a result of selective attack was time-dependent. The increase in the water vapor decreased the measurable corrosion attack, and in addition, decreased sulfation was observed. Results from the current investigation and from previously reported findings suggest that an increase in the water vapor content will cause competitive adsorption on active sites.

Pitting corrosion inhibition of type 304 austenitic stainless steel by 2-amino-5-ethyl-1,3,4-thiadiazole in dilute sulphuric acid

The electrochemical behaviour and inhibitor protection of 2-amino-5-ethyl-1,3,4-thiadiazole (TTD) on the pitting corrosion of austenitic stainless steel (type 304) in dilute sulphuric acid solution contaminated with recrystallised sodium chloride was evaluated with the aid of potentiodynamic polarization method. TTD greatly reduced the corrosion rate of the steel with a corrosion inhibition efficiency ranging from 88.99–87.36%. The corrosion potential, pitting potential, repassivation potential, nucleation resistance, passivation range and repassivation capacity measurements and potentiodynamic studies were applied to assess the steel’s pitting resistance characteristics and behaviour in the acid chloride media. Results showed that pitting potential values increased with addition of TTD compound in conjunction with increase in the passivation range which strongly indicating increased electrochemical resistance to pitting corrosion.

ICONE23-1530 Effect of boiling phenomena on the corrosion of austenitic stainless steel (R-SUS304ULC) in nitric acid solution containing chromium ions

ICONE23-1530 Effect of boiling phenomena on the corrosion of austenitic stainless steel (R-SUS304ULC) in nitric acid solution containing chromium ions

Redox behavior of chromium on the corrosion of austenitic stainless steel (R-SUS304ULC) in 8 M nitric acid solution

We investigated the relationship between the corrosion of austenitic stainless steel (R-SUS304ULC) and the redox behavior of chromium in nitric acid solution under three conditions – boiling at atmospheric pressure, boiling at reduced pressure, and non-boiling – to evaluate the effects of the boiling phenomenon. In the Cr(III) oxidation rate measurement, about 20% of the Cr(III) was oxidized to Cr(VI) under atmospheric-pressure boiling at 384 K after 168 h. Under non-boiling conditions at 373 K, Cr(VI) was not observed. However, about 3% of Cr(III) oxidation was observed at 373 K with reduced-pressure boiling. Thermodynamic calculations showed that the abundance of Cr(VI) in boiling nitric acid was increased over that in non-boiling nitric acid, even at the same temperature. These results show that Cr(III) is more likely to oxidize under boiling conditions than non-boiling conditions. On the other hand, in the corrosion tests, we found that the apparent reduction rate of Cr(VI) as a result of corrosion of R-SUS304ULC was more than 10 times greater than the Cr(III) oxidation rate. Therefore, the corrosion of R-SUS304ULC appears to be dominated by the rate of Cr(VI) reduction in nitric acid solution regardless of the boiling or non-boiling conditions.

Evaluation of the intergranular corrosion in austenitic stainless steel using collinear wave mixing method

Failures due to intergranular corrosion in components of austenitic stainless steel have always been a tough problem in engineering practice. In this paper, the collinear wave mixing was investigated to evaluate the intergranular corrosion in austenitic stainless steel. An acoustic nonlinearity parameter related to the bispectrum, the propagation distance and the amplitudes of fundamental waves in measured signal is proposed. Nonlinear acoustic measurements were conducted on four tubes with different degree of intergranular corrosion. The experimental results demonstrated that the proposed acoustic nonlinearity parameter is sensitive to intergranular corrosion in samples, and is well correlated with the degree of damage.

Influence on Pitting Corrosion Behavior of Welded AISI30400 Plate in a Freeze-Thaw Environment

Welded structures which set up in outdoor in snow-and cold-prone areas are exposed to severe environment, in which liquids containing Cl-chloride ions from the sea breeze and snow melting agents undergo freeze-thaw cycles during the winter. Cl-solutions are known to produce pitting corrosion in austenitic stainless steel. However, the relationship between the freeze-thaw environment and pitting corrosion occurred in welded austenitic stainless steel has not yet been clarified. In the present study, the effect of the freeze-thaw environment on pitting corrosion in welded austenitic stainless steel submersed in Cl-solutions is investigated. AISI 304 (X5CrNi18-10 in ISO/TS 15510, SUS304 in JIS G 4305) samples with bead-on-plate welding are used as specimens. The thickness of the specimen is 4 mm. The specimens are fully immersed in FeCl3 solution. The freeze-thaw environment is created by temperature cycling from 20°C to-20°C. In the meanwhile, residual stresses due to the welding process in stainless steel structures can significantly affect behavior of pitting corrosion as same as influence of sensitization. Authors carried out the welding simulation as the purpose of predicting the welding-heat history and residual stress near the welding bead. As a result, large-scale pitting corrosion occurs primarily in areas of high tensile residual stress and sensitive metallographic structures near weld beads in the freeze-thaw environment. Accelerated pitting corrosion is confirmed to have occurred as a result of concentration cell corrosion due to the local concentration of Cl-chlorine ion around a weld bead during freezing and thawing of the solution. Furthermore, based on your study it became clear that the center position of large-scale pitting corrosion is in agreement with the simulation result rather than the stress peak position by X rays measurement.

208 オーステナイトステンレス鋼の腐食と疲労特性に及ぼす予ひずみの影響

208 オーステナイトステンレス鋼の腐食と疲労特性に及ぼす予ひずみの影響

Intergranular Corrosion of Austenitic Stainless Steel

In the paper, the characteristic of intergranular corrosion on austenitic stainless steel is presented. The principles and the influencing factors of intergranular corrosion are analyzed in detail. Furthermore, the effective measures to prevent intergranular corrosion are proposed. Finally, the evaluation methods of sensitivity to intergranular corrosion are introduced.

Inhibition Effect of Kola Tree and Tobacco Extracts on the Corrosion of Austenitic Stainless Steel in Acid Chloride Environment

Inhibition Effect of Kola Tree and Tobacco Extracts on the Corrosion of Austenitic Stainless Steel in Acid Chloride Environment

Effect of Rolling on Locarized Corrosion of Austenitic Stainless Steels

Effect of Rolling on Locarized Corrosion of Austenitic Stainless Steels

The inhibition effect of some pyrimidine derivatives on austenitic stainless steel in acidic media

5-Benzoyl-4-(substitutedphenyl)-6-phenyl-3,4-dihydropyrimidine-2(1 H)-(thio)ones (DHPMs) (I and II) were synthesized using the Biginelli three component cyclocondensation reaction of an appropriate β-diketone, arylaldehyde, and (thio) urea. The effect of these corrosion inhibitors on the corrosion of austenitic stainless steel in 0.5 M H 2SO 4 has been studied by electrochemical methods using Tafel plot, linear polarization and electrochemical impedance spectroscopy at 298 K. The inhibition efficiencies obtained from all the methods employed are in good agreement. The adsorption of the DHPMs onto the stainless steel surface was found to follow Langmuir and Dubinin–Radushkevich adsorption isotherm models. Negative values of Δ G ads in the acidic media ensured the spontaneity of the adsorption process. Results show DHPM I to be the best inhibitor with a mean efficiency of 91% at 2 × 10 −3 M additive concentration.

Corrosion inhibition of austenitic stainless steel by some pyrimidine compounds in hydrochloric acid

AbstractThe inhibition effect of two pyrimidine derivatives on the corrosion of austenitic stainless steel in 1 M HCl has been studied by Tafel plot, linear polarization, and electrochemical impedance spectroscopy (EIS) at 298 K. Results showed that compounds inhibited steel corrosion in a 1 M HCl solution and inhibition efficiencies increased with the concentration of inhibitor. Polarization curves indicated that all studied pyrimidine derivatives act as mixed type (cathodic/anodic) inhibitors. The adsorption of the inhibitors on the stainless steel surface was found to obey the Langmuir and Dubinin–Radushkevich adsorption isotherm models. Negative values of ΔGads in the acidic media ensured the spontaneity of the adsorption process.

Identification of MnCr 2O 4 nano-octahedron in catalysing pitting corrosion of austenitic stainless steels

Pitting corrosion of stainless steels, one of the classical problems in materials science and electrochemistry, is generally believed to originate from the local dissolution in MnS inclusions, which are more or less ubiquitous in stainless steels. However, the initial location where MnS dissolution preferentially occurs is known to be unpredictable, which makes pitting corrosion a major concern. In this work we show, at an atomic scale, the initial site where MnS starts to dissolve in the presence of salt water. Using in situ ex-environment transmission electron microscopy (TEM), we found a number of nano-sized octahedral MnCr 2O 4 crystals (with a spinel structure and a space group of Fd 3 ¯ m) embedded in the MnS medium, generating local MnCr 2O 4/MnS nano-galvanic cells. The TEM experiments combined with first-principles calculations clarified that the nano-octahedron, enclosed by eight {1 1 1} facets with metal terminations, is “malignant”, and this acts as the reactive site and catalyses the dissolution of MnS. This work not only uncovers the origin of MnS dissolution in stainless steels, but also presents an atomic-scale evolution in a material’s failure which may occur in a wide range of engineering alloys and biomedical instruments serving in wet environments.

A study of intergranular corrosion of austenitic stainless steel by electrochemical potentiodynamic reactivation, electron back-scattering diffraction and cellular automaton

The impact of solution and sensitization treatments on the intergranular corrosion (IGC) of austenitic stainless steel (316) was studied by electrochemical potentiodynamic reactivation (EPR) test, and the results showed the degree of sensitization (DOS) decreased as solution treatment temperature and time went up, but it increased as sensitization temperature prolonged. Factors that affected IGC were investigated by field emission scanning electron microscope (FE-SEM) and electron back-scattering diffraction (EBSD). Furthermore, the precipitation evolution of Cr-rich carbides and the distribution of chromium concentration were simulated by cellular automaton (CA), clearly showing the effects of solution and sensitization treatments on IGC.

ステンレス鋼製再処理用機器へのカソード防食の適用性に関する研究

An application of a cathodic protection method with an impressed current system to control the corrosion of austenitic stainless steel in a boiling nitric acid solution was studied to improve corrosion resistance and to extend the operation life of components in a fuel reprocessing plant. Plate-type specimens made of ultralow carbon type 304 stainless steel (SUS304ULC) were immersed in 3 mol·dm−3 boiling nitric acid solutions including 10 and 1.7 g·dm−3 vanadium ions. Electrochemical potentiostatic tests and cathodic protection tests were performed using electrochemical test cells. The selected protective potential was below the transition potential between the passive and trans-passive states based on anodic polarization measurement. Corrosion rates in the solution with and without the protection were measured by potentiostatic tests. Additionally, the outer surface of the tube-type specimen of SUS304ULC was studied under the same condition. From the obtained results, corrosion rates of plate-type specimens with cathodic protection were observed to decrease by 1/40 and 1/10 those of the specimens without cathodic protection in the solutions including 10 and 1.7 g·dm−3 vanadium ions, respectively. In the case of tube-type specimens, outer surface thickness loss was decreased from 24 to 3 μm by the protection, and platinum was chosen as the anode because it showed no corrosion loss like gold and no cracking like zirconium. Authors concluded that the cathodic protection method can be expected as one of the methods of maintaining components in a fuel reprocessing plant.

Influence of glyoxal on localized corrosion of austenitic stainless steel in spring water

AbstractThis paper presents the research regarding the influence of glyoxal on electrochemical and corrosion behaviour of austenitic stainless steel in water. For this purpose, model solutions containing glyoxal in water in concentrations ranging from 0.1 to 1 % were prepared. Spring water was used as control electrolyte. From the potentiostatic polarisation data (using the standard three‐electrode system), the corrosion current (icorr), corrosion potential (Ecorr) and polarisation resistance (Rp) were calculated. The research included also the conductivity, total dissolved soils, salinity, resistivity and pH, absolute potential, and relative potential of model solutions. The presence of glyoxal at the highest concentration of 1 % in the water solution has accelerating effect on corrosion.