Corrosion Test Data Research Articles

Study of Global Seawater Corrosivity Classification Based on Marine Environmental Factors Data

ABSTRACTTo evaluate the global seawater corrosivity and ensure the service safety of marine equipment, the methods of seawater corrosivity classification, which contained the standard metal corrosion rates method and the environmental factors evaluation method, are proposed and then applied to the seawater corrosivity classification in typical China seas. By comparing the results from both methods, the feasibility of the environmental factors evaluation method based on the grey relational model is verified. Furthermore, with the collection and processing of typical seawater factors data of global ocean, the corrosivity of global seawater is classified into six grades with the corrosion test data of carbon steel as baseline, and its distribution in different months is visualized by means of ArcGIS technology. The results show that the sea areas with high corrosivity are mainly located at equatorial and tropical sea areas, and for carbon steel, seawater temperature was the main influence on seawater corrosivity.

Coupling multi-physics models to corrosion fatigue prognosis of high-strength bolts in floating offshore wind turbine towers

Floating wind offshore turbines (FOWTs) tap into the immense Aeolian resource in deep-water oceans. The turbine structure, especially in ring-flange (RF) connections, are highly prone to corrosion fatigue (C-F) deterioration due to the combination of strong wind-wave loads, structural flexibility, and high corrosivity. This study provides innovative insights into the C-F deterioration of FOWT towers by integrating site-specific data, material test results, multi-physics simulations, and deterioration models. A probabilistic C-F (PCF) evolution model is tailored for bolts in RF connections, accounting for multiple failure modes. Concurrently, the corrosion test data are adopted to estimate the corrosion rate from the site-specific ambient conditions, including the temperature, humidity and airborne salinity. The result indicates a strong correlation between wind-wave spatial distribution and C-F damage, for which the critical bolt aligns with high-velocity winds. Meanwhile, the bolt deterioration is accelerated under high corrosivity, risking premature failures. Moreover, compared with the traditional fixed-bottom foundation, the floating platform amplifies the tower dynamics in both mean value and variation, which in turns escalate stress ranges in bolts. The findings underscore the importance of monitoring C-F deterioration in FOWT structures and highlight the potential of condition-based maintenance.

ПРОТИВОКОРРОЗИОННАЯ ЗАЩИТА СТАЛИ СОСТАВАМИ НА ОСНОВЕ БИТУМНОГО ПРАЙМЕРА

The use of anti-corrosion protection is necessary to extend the service life of agricultural equipment; bitumen compounds can traditionally be used for this purpose. The effectiveness of compositions based on a bitumen primer, into which white spirit solvent and a corrosion inhibitor were additionally introduced in an amount of 5 wt. %: CO-FFA, paraffin, Emulgin, has been studied. Studies have shown that the bitumen primer is frost-resistant, and the thickness of its coatings increases as expected when several layers are applied. Corrosion tests were carried out in a thermal and moisture chamber G-4, in a solution of 0.5 M NaCl and in a natural atmosphere (full-scale bench studies). According to the results of tests in the G-4 thermal and moisture chamber, all compositions, both in the presence of an inhibitor and without it, almost completely protect the steel surface. Corrosion test data in 0.5 M NaCl showed that the effectiveness of the bitumen primer is 75%, and the addition of paraffin, Emulgin or KO-SZhK to the additive increases the protective effect to 98, 94, 87%, respectively. The composition with the addition of paraffin turned out to be the most effective according to the results of full-scale bench tests (Z = 93%), as evidenced by the appearance of the plates after the experiment. It is recommended that production tests be carried out using the latest formulation.

Exploring the potential of transfer learning in extrapolating accelerated corrosion test data for long-term atmospheric corrosion forecasting

This study utilizes transfer learning (TL) to enhance long-term atmospheric corrosion predictions. Using a Fe/Cu galvanic-type sensor, we gathered data in a controlled SAE J2334 salt spray setting and transferred this to an uncontrolled outdoor environment. Among TL methods tested, freezing the initial layer and fine-tuning others at a lower rate was most effective. The approach excelled at forecasting outdoor corrosion behaviour using a limited dataset. This approach could provide a solution to extrapolate results from controlled corrosion tests to unpredictable outdoor conditions and addressing data scarcity in machine learning modelling in the context of atmospheric corrosion.

On the peak strength of 7050 aluminum alloy: mechanical and corrosion resistance

This work consists of an experimental study on the ageing response and resulting properties of AA7050 plate material. New heat treatments are investigated for achieving a peak-aged temper, as a T6 temper may be said to be, that achieves yield and tensile strengths superior to those of the documented T7 treatments. For this alloy, the Standard establishes T7X tempers which were developed to obtain a very good compromise between mechanical strength and corrosion resistance. Nevertheless, for all those applications in which the environment is not considered critical for corrosion behaviour, the peak strength condition could be beneficial. In this experimental work, the authors use standard hardness testing to investigate mechanical response as a function of ageing time at several ageing temperatures, all applied immediately after solution. Upon identifying specific times and temperatures of interest, specimens aged under the selected treatments were subjected to tensile testing and intergranular corrosion testing. The results show that a single-step ageing heat treatment is able to produce a significantly high both yield and ultimate tensile strength. Moreover, the corrosion test data indicates that this new heat treatment produces corrosion resistance similar to that of the T76 heat treatment.

Binary Inhibitory Anti-Rust Paint

A combined approach to paint was used to increase the effectiveness of anti-corrosion protection was used. In particular, passive insulating coating materials was modified with active additives. A water-soluble anodic inhibitor of atmospheric corrosion was encapsulated in a phosphate conversion coating NOTECH. As a result, the corrosion under a layer of paint primer was suppressed. It is important that phosphating does not create a layer like paint. So, such an approach is universal and compatible with most known types of paint coatings and can be combined with temporary protection (preservation). The second paint layer of the coating contained a water-oil-soluble corrosion inhibitor of the group “M”, namely: N-M-1. It is adduct of natural fat vegetable acids and cyclohexylamine. The data of corrosion tests and polarization curves are presented, which confirm the high protective properties of the proposed binary inhibitory anti-rust paint.

Experimental Study on the Relationship between the Natural Frequency and the Corrosion in Reinforced Concrete Beams

Due to many nondamage factors such as temperature, humidity, carbonation, and corrosion effects on natural frequency, the key problem of the application frequency‐based method to detect damage is to reveal the rules of these factors affect natural frequency and further to eliminate their effects. The long‐term characteristics of reinforced concrete structures require a lot of attention, especially in corrosive environment. In this paper, an experimental investigation was conducted to study the deflection and natural frequency of reinforced concrete beam in a marine environmental chamber for six corrosion stages (accelerated corrosion for 0, 20, 40, 70, 100, and 140 days). The experimental results demonstrated that deflection increases with corrosion time, while natural frequency decreases with corrosion time. Based on the accelerate corrosion test data of reinforced concrete beams, the general expression of the relationship between corrosion depth and natural frequency has been established through the fitting curve method. The polynomial model has been selected for establishing the relationship between steel corrosion depth (including the main reinforcement and stirrup) and natural frequency. The reason for selecting the polynomial model is that the sum of squares due to error (SSE) is closer to 0 and the coefficient of multiple determination (R‐square) is closer to 1. This investigations help to discriminate the cause of reinforced concrete beams natural frequency change, to eliminate nondamage factors affects, and to apply many structural damage identification methods effectively.

Influence of the Range of Particle Sizes of the Powder Component of Saturating Medium on the Carbooxidation of Titanium Alloys

We present the results of carbooxidation of VT1-0 and OT4 titanium alloys performed with the use of a powder carbon component of saturating medium with solid fractions whose sizes vary within the range 45–300 μm (saturation from soot, graphite, and charcoal). The results of metallographic, durometric, and profilometric investigations and the X-ray phase diffraction analysis reveal certain differences between the characteristics of the newly formed modified layers. The data of corrosion and electrochemical tests carried out in an 80% solution of sulfuric acid demonstrate that the efficiency of the carbooxidation increases as the sizes of solid fractions of the powder carbon component of the saturating medium decrease.

Plasma Electrolytic Boriding of Steels and Titanium Alloys

Results of diffusion saturation of steels and titanium alloys with boron and other elements under cathodic and anodic electrolysis plasma are considered. Processing regimes and electrolytes compositions, structural features of modified layers, their microhardness, surface roughness, as well as data of tribological and corrosion tests in various environments are presented. The treatment conditions are found to significantly increase the wear resistance and corrosion resistance of structural steels and titanium alloys. A conclusion is made on the prospects of electrolytic-plasma treatment; plasma electrolytic boriding has proven its potential; the advantages and limitations of the method are noted, including promising areas for further research.

Data on triethylenetetramine effect on steel-rebar corrosion-rate in concrete immersed in 0.5 M H 2 SO 4

Abstract In this article, the dataset on the effect of different triethylenetetramine (TETA: C6H18N4) concentrations on the corrosion-rate of steel-rebar embedment in steel-reinforced concrete immersed in 0.5 M H2SO4 (for simulating industrial/microbial environment) is presented. The corrosion test-data was obtained from weekly monitoring, over seven weeks of steel-reinforced concrete immersion, using linear-polarization-resistance (LPR) measuring instrument. The dataset and its requisite analyses, as per ASTM G16 —13, are presented in graphs and tables. The analyses detailed include descriptive statistics of the Normal, Gumbel and Weibull probability distribution functions (pdf's), and tests-of-fit significance by the Kolmogorov-Smirnov goodness-of-fit statistics. The detailed information from this corrosion tests dataset is useful for further research on the inhibition mechanism and effectiveness of the triethylenetetramine chemical on the corrosion-protection of reinforcing-steel material in steel-reinforced concrete designed for the industrial/microbial service-environment.

Ion beam processing of austenite steels: Tribotechnical and corrosion properties

This article presents data on wear and corrosion resistance of 10Kh17N13M2T and 55Kh20G9AN4 austenite steels processed by nitrogen ions. It has been demonstrated that the temperature of ion beam nitrogenation significantly influences structure and phase transformations and properties of materials. The obtained values of electron work function agree with the data of tribotechnical and corrosion tests.

A high-sensitivity scanning magnetometer based on the giant magneto-impedance effect for measuring local magnetic fields of corrosion currents

The design, main characteristics, and specific features of a new high-sensitivity magnetometer based on the giant magneto-impedance (GMI) effect in amorphous ferromagnetic microwires are considered. It is shown that, in addition to measuring homogeneous fields, the device is capable of detecting weak local magnetic fields of conduction currents and ion currents involved in corrosion processes. Results of in situ magnetic measurements of corrosion processes in the model system of copper–zinc in a sulfuric acid solution qualitatively agree with the data of direct corrosion tests employing the standard gravimetric method.

Organofunctional Silane Inhibitor Surface Treatment of Concrete for Corrosion

With increased attention to service life, bridge decks are now being designed to perform for 75 to more than 100 years without major repairs. In areas where deicing salts are used, sustainable and cost-effective solutions utilize concretes with a water-to-cementitious material ratio (w/cm) less than 0.40, concrete cover over the reinforcement greater than or equal to 2 in., and additional corrosion protection measures, such as corrosion-resistant reinforcement or corrosion inhibitors. Concretes with a w/cm less than 0.40 require higher cement contents and can be more susceptible to cracking, even with the use of supplementary cementitious materials. This paper discusses 3 years of accelerated corrosion test data on an alternative solution that could utilize more moderate cementitious levels but still reduce chloride ingress and potentially raise chloride threshold levels for corrosion initiation by applying a low surface tension organofunctional silane inhibitor to the surface before exposure to chloride.

Corrosion Rate and Noise Resistance Correlation from NaNO2-Admixed Steel-Reinforced Concrete

The lack of correlation from measurements of corrosion potential with corrosion rate in corrosion monitoring of steel-reinforced concrete has constituted concerns instigating demands for further experiments or additional monitoring techniques in corrosion studies. This paper studies correlation of corrosion rate from linear polarization resistance instrument and noise resistance from the ratio of standard deviations of corrosion potential to that of corrosion current measured from NaNO2-admixed steel-reinforced concrete in 3.5% NaCl. Different concentrations of NaNO2 were admixed in replicates of steel-reinforced concretes immersed in the saline/marine simulating test-solution and corrosion of the embedded steel-rebar were monitored using the three different, non-destructive, electrochemical methods. Measurements of corrosion test-data from these were subjected to the descriptive statistics of the Weibull distribution function, for which test-data compatibility was ascertained using the Kolmogorov-Smirnov goodness-of-fit statistics. The analysed results of the measured corrosion test-variables, exhibited good correlation between the corrosion rate, as the dependent variable and the function of the admixed NaNO2 molar concentration and the noise resistance, as independent variables. Both experimental and prediction, from correlation fitting, models identified 0.1208 M NaNO2, the optimal concentration employed in the study, with optimum effectiveness, of η>90%, at inhibiting steel-rebar corrosion in the corrosive solution of concrete test-immersion. These bear suggestions of the suitability of the analysed more easily measured corrosion potential and corrosion current for indicating the corrosion activity of steel-reinforcement in concrete designed for corrosive service-environments.

Evaluation of corrosion behaviors for reactor pressure vessels/primary containment vessels in Fukushima Daiichi units 1–3 nuclear power plant

Fukushima Daiichi nuclear power plants (1F) were damaged by unprecedented severe accident in the Great East Japan Earthquake on 11 March 2011, and seawater has been injected as an emergency countermeasure for the core cooling. Although, the RPV and PCV were not supposed to be exposed to diluted seawater, they have been exposed to diluted seawater environment or high-moisture environment. Therefore, seawater corrosion has become an important issue. Immersion corrosion tests were performed for low-alloy steel of RPV material and carbon steel of PCV material in 1F cooling-water-simulated environment. As a result, the mass loss by corrosion was reduced with the decreasing temperature and chloride ion concentration. Moreover, the effects of nitrogen deaeration and Na2WO4 addition on corrosion protection were remarkable among the selected corrosion countermeasures. In addition, the integrity assessments of RPV and PCV were performed considering the reduction of plate thickness based on corrosion test data and the load condition based on earthquake response analysis results. It had been confirmed that primary stresses for RPV and PCV equipment satisfied with the allowable values until at least 15 years after the accident.

Probability density fittings of corrosion test-data: Implications on C6H15NO3 effectiveness on concrete steel-rebar corrosion

In this study, corrosion test-data of steel-rebar in concrete were subjected to the fittings of the Normal, Gumbel and the Weibull probability distribution functions. This was done to investigate the suitability of the results of the fitted test-data, by these distributions, for modelling the effectiveness of C6H15NO3, triethanolamine (TEA), admixtures on the corrosion of steel-rebar in concrete in NaCl and in H2SO4 test-media. For this, six different concentrations of TEA were admixed in replicates of steel-reinforced concrete samples which were immersed in the saline/marine and the microbial/industrial simulating test-environments for seventy-five days. From these, distribution fittings of the non-destructive electrochemical measurements were subjected to the Kolmogorov–Smirnov goodness-of-fit statistics and to the analyses of variance modelling for studying test-data compatibility to the fittings and testing significance. Although all fittings of test-data followed similar trends of significant testing, the fittings of the corrosion rate test data followed the Weibull more than the Normal and the Gumbel distribution fittings, thus supporting use of the Weibull fittings for modelling effectiveness. The effectiveness models on rebar corrosion, based on these, identified 0.083% TEA with optimal inhibition efficiency, η = 72.17± 10.68%, in NaCl medium while 0.667% TEA was the only admixture with positive effectiveness, η = 56.45±15.85%, in H2SO4 medium. These results bear implications on the concentrations of TEA for effective corrosion protection of concrete steel-rebar in saline/marine and in industrial/microbial environments.

Long-Term Corrosion of Zircaloy Hull Waste under Geological Disposal Conditions: Corrosion Correlations, Factors Influencing Corrosion, Corrosion Test Data, and Preliminary Evaluation

ABSTRACTThe carbon-14 generated in Zircaloy (Zry) hull waste is considered an important radionuclide in the TRU waste geological disposal concept in Japan. Given that the metal Zry is highly corrosion-resistant in the anaerobic and low-temperature conditions of the repository, and that the C-14 release rate is assumed to be controlled by the corrosion rate, a variety of corrosion and leaching tests have been performed. However, since the Zry corrosion rate is extremely slow, it is not possible to predict long-term corrosion behavior through low-temperature corrosion tests conducted in a reasonable time period. A vast amount of testing has been conducted in the higher-temperature range of 523 to 633 K, and corrosion correlations have been obtained from these tests. Corrosion correlations have been used to predict the corrosion rate of Zry in a tuff repository. Long-term Zry autoclave corrosion data have been analyzed to develop new corrosion correlations. Extrapolating these correlations to a lower temperature range requires verification that the mechanisms do not change over the range of testing and extrapolation. Factors that influence corrosion rates under geological disposal conditions, such as material and environmental factors, should also be examined. Corrosion correlations, factors influencing corrosion rates, the results of corrosion and leaching tests, and a preliminary evaluation are discussed.

Analysis of inhibition of concrete steel-rebar corrosion by Na2Cr2O7 concentrations: Implications for conflicting reports on inhibitor effectiveness

Corrosion test data were measured using non-destructive electrochemical techniques and analysed for studying inhibition effectiveness by different concentrations of Na2Cr2O7 on the corrosion of concrete steel-rebar in NaCl and in H2SO4 media. For these, specifications of ASTM G16-95 R04 were combined with the normal and the Gumbel probability density functions as model analytical methods for addressing issues of conflicting reports of inhibitor effectiveness that had generated concerns. Results show that reinforced concrete samples admixed with concentrations having 4 g (0.012 7 mol), 8 g (0.025 4 mol) and 6 g (0.019 1 mol) Na2Cr2O7 exhibited, in that order, high inhibition effectiveness, with respective efficiency, η, of (90.46±1.30)%, (88.41±2.24)% and (84.87±4.74)%, in the NaCl medium. These exhibit good agreements within replicates and statistical methods for the samples. Also, optimal inhibition effectiveness model in the H2SO4 medium was exhibited by 8 g (0.025 4 mol) Na2Cr2O7 concentration having η=(78.44±1.10)%. These bear implications for addressing conflicting test data in the study of effective inhibitors for mitigating steel-rebar corrosion in aggressive environments.

Challenges in Correlating In Vitro Corrosion Data to In Vivo Performance for Implantable Electrode Materials

Standard in vitro tests are useful to identify corrosion susceptibility, material heterogeneity, and basic corrosion byproduct toxic screening. However, those tests do not adequately account for important interactions between the device, the material and the implant host. In vivo processes such as fibrotic tissue encapsulation of implanted electrodes modulate current density distribution effects and thus influence local dissolution rates and charge injection. Electrode and conductor transient effects such as potential and current excursions may be important, or may have minimal effect in the implanted system. Corrosion byproducts of local microenvironments can have a profound effect in the stability of adjacent materials, i.e., metal induced oxidation (MIO) of polyurethanes. Those effects can be mitigated via appropriate design and selection of materials. Corrosion test data analysis should include a system level risk assessment with full awareness of in vivo use, and an estimation of corrosion effect propagation, no matter how small the individual component effects may be.

Long term corrosion characteristics of metallic materials in marine environments

Long term corrosion test data in marine environments are essential data to guide the design and application of marine engineering. Corrosion test results, over a 16 year period from October 1986 to October 2002, using eight kinds of metallic materials are reported in this paper. Materials were exposed in the splash zone, tidal zone, and full immersion zone of four corrosion test stations located in Qingdao, Zhoushan, Xiamen and Yulin respectively, and therefore the corrosion behaviour of various ferrous and non-ferrous materials in these marine environments has been obtained. The corrosion of carbon steel in the seawater fits the following general relationship: D=A+K(t–1). The variation in the general corrosion rates for the different carbon steels in seawater is relatively small and consistent. However, the pitting corrosion rates for the different carbon steels are all significantly different. The marine splash zone is about 0–2˙4 m above the mean high water level of the seawater. The corrosion peak was located about 0˙6 to 1˙2 m above the mean high water level. The order of the corrosion potential of stainless steels with the corrosion resistance of stainless steels is consistent in seawater. The corrosion of copper was found to be serious in the full immersion zone of the Yulin sea area. The effective lifetime of the cathodic protection for a wrapped aluminising layer of the hard and ultrahard aluminium may be 16 years.