Corrosion Behavior Of Q235 Steel Research Articles

A comparative study on the corrosion behavior of Q235 steel in saturated acidic red and yellow soils

Purpose The purpose of this paper is to study the corrosion behavior of Q235 steel in saturated acidic red and yellow soils. Design/methodology/approach The corrosion behavior of Q235 steel in saturated red and yellow soils was compared by weight-loss, SEM/EDS, 3D ultra-depth microscopy and electrochemical measurements. Findings Rp of the steel gradually increases and icorr gradually decreases in both the red and yellow soils with time. The Rp of the steel in the red soil is lower, but its icorr is higher than that in the yellow soil. The uniform corrosion rate, diameter and density of the corrosion pit on the steel surface in the red soil are greater than those in the yellow soil. Lower pH, higher contents of corrosive anions and high-valence Fe oxides in the red soil are responsible for its higher corrosion rates and local corrosion susceptibility. Originality/value This paper investigates the difference in corrosion behavior of carbon steel in saturated acidic red and yellow soils, which can help to understand the mechanism of soil corrosion.

Effect of moisture on corrosion behavior of Q235 steel in bentonite clay

The corrosion behavior of Q235 steel in bentonite clay at various moisture contents was studied using conductivity and electrochemical measurements as well as micro-morphology analysis. The results showed that Na-based bentonite clay exhibited better water absorption, higher conductivity, and lower corrosivity than Ca-based bentonite clay, and the corrosion rate in Na-based bentonite clay was considerably lower than that in the soil of Hunan province. The main corrosion style of steel in the Na-based bentonite clay was local corrosion in clusters. With an increasing moisture content of the bentonite clay, the corrosion potential of the steel decreased, while the corresponding corrosion rate, current density and local corrosion sensitivity firstly increased and then decreased at above 30 wt% moisture. Na-based bentonite clay is a desirable base material as resistance-reducing agents (RRAs) added to the soil for grounding. However, the corrosivity and moisture of the bentonite clay should be considered during the design of grounding RRAs.

Laser cavitation processing of mild steel: Surface integrity, microstructure and stress corrosion performance

Laser cavitation peening (LCP) is a new and effective technology for surface modification. The Q235 steel was processed by LCP and aluminum foil was employed as a coverage layer. Moreover, the Q235 steel was also treated by laser cavitation peening without a coverage layer (LCPwc). The surface integrity, microstructure, and stress corrosion behavior of Q235 steel processed by LCP and LCPwc were systemically studied. According to the experimental results, the mechanisms of LCP strengthening and stress corrosion performance of Q235 steel were revealed. The results indicate that LCP and LCPwc result in the surface plastic deformation of Q235 steel. The residual compressive stress is induced and microhardness is enhanced. On the surface layer of Q235 steel, the grains were refined and many dislocation structures produce. The impact of LCPwc and LCP enhances the yield strength and ultimate strength of Q235 steel, while the elongation decreases. The corrosion resistance and mechanical properties of Q235 steel are improved significantly after the processing of LCPwc and LCP. The Q235 after LCP processing has better mechanical properties while the LCPwc treatment makes the material have better anti-corrosion performance.

A novel method for identifying corrosion types and transitions based on Adaboost and electrochemical noise

PurposeThe purpose of this paper is to identify corrosion types and corrosion transitions by a novel electrochemical noise analysis method based on Adaboost.Design/methodology/approachThe corrosion behavior of Q235 steel was investigated in typical passivation, uniform corrosion and pitting solution by electrochemical noise. Nine feature parameters were extracted from the electrochemical noise data based on statistical analysis and shot noise theory. The feature parameters were analysis by Adaboost to train model and identify corrosion types. The trained Adaboost model was used to identify corrosion type transitions.FindingsAdaboost algorithm can accurately identify the corrosion type, and the accuracy rate is 99.25%. The identification results of Adaboost for the corrosion type are consistent with corroded morphology analysis. Compared with other machine learning, Adaboost can identify corrosion types more accurately. For corrosion type transition, Adaboost can effectively identify the transition from passivation to uniform corrosion and from passivation to pitting corrosion consistent with corroded morphology analysis.Originality/valueAdaboost is a suitable method for prediction of corrosion type and transitions. Adaboost can establish the classification model of metal corrosion, which can more conveniently and accurately explore the corrosion types. Adaboost provides important reference for corrosion prediction and protection.

Weak impact of underground water on corrosion inhibition of resistance-reducing agent

PurposeThe purpose of this paper is to study the corrosion behavior of Q235 steel in the bentonite-based resistance-reducing agent (RRA) with different infiltration rates of underground water.Design/methodology/approachThe corrosion behavior of the steel in underground water was assessed by weight loss experiment, electrochemical impedance spectroscopy and polarization curve.FindingsThe results showed that the corrosion rate of the steel in the RRA pastes was much lower than that in the original acidic soil. The underground water infiltration slightly accelerated the corrosion rate of the steel in the RRA pastes, but the acceleration role is weak. The bentonite-based RRA can be compatibly applied in the acidic soil.Originality/valueThe bentonite-based RRA can significantly reduce the corrosion rate of the steel and is suitable to compatibly apply in the acidic soil.

Study on Corrosion Behavior of Q235 Steel and 16Mn Steel by Electrochemical and Weight Loss Method

Study on Corrosion Behavior of Q235 Steel and 16Mn Steel by Electrochemical and Weight Loss Method

Corrosion behavior of Q235 steel by synergistic action of high concentration Cl− and complex scale in mixed salt flooding

The corrosion mechanism of Q235 steel by the synergistic effect of high concentration Cl− and complex scale in the preparation process of a mixed salt oil displacement method was investigated using measurements of weight loss, electrochemical impedance spectroscopy, linear polarization curve and open circuit potential. Scanning electron microscope and energy dispersive spectroscopy results indicated that the amount of Na2CO3 in the preparation process had an influence on the composition of the complex scale. This study investigated the corrosion process on Q235 steel using solutions with three different CO32−/Cl− molar ratios R: 0.11, 0.27, and 0.37. At a low concentration of CO32−, serious pitting corrosion occurred and the composition of corrosion product was diverse. When the R was 0.27, a discontinuous passive film was formed on the metal surface, and crevice corrosion took place between the adsorbed Si scale and substrate. With a further increased in CO32− concentration, the steel surface was covered with a passive film that was mainly composed of FeCO3 and Fe2O3. The initial growth process of calcium carbonate was restricted. At the R = 0.37 solution, corrosion was successfully inhibited, making this a good candidate for use in the oil recovery process.

Corrosion behavior of Q235 steel in graphene oxide aqueous dispersion

Conductive metals can speed up the self-assembly and reduction process of graphene oxide (GO) in liquid media, but there is little available information about the effect of this process on the corrosion rate of metal substrates. The corrosion performance of Q235 steel in GO aqueous solution was studied by comparing the influence of different GO concentrations and immersion times on the corrosion rate of steel. The result found that a GO layer will be formed on the surface of steel when immersing in the GO aqueous dispersion, which has a shielding effect on the diffusion process of ions and electrons, and effectively inhibits the steel corrosion. However, this inhibition effect of GO layer will disappear with the self-reduction of GO, which increasing the defect density and conductivity of the sedimentary layer on steel and thus the corrosion rate of steel will increase with the immersion time and the GO concentration in solution.

Study on Corrosion Behavior of Q235 Steel in a Simulated Marine Tidal Environment

Study on Corrosion Behavior of Q235 Steel in a Simulated Marine Tidal Environment

Time- and temperature-dependence of the anticorrosion effect of sodium sulfide on Q235 steel for post-combustion CO2 capture system

As a heat stable salt, sodium sulfide remains thermally-unregenerable during the regeneration process for post-combustion capture. Therefore, it became important to undertake a full assessment of its potential presence in the system. The paper investigates the mechanism and influence of sodium sulfide on the corrosion behavior of Q235 steel in amine-based post-combustion CO2 capture technology with respect to exposure time and temperature. The inhibitive influence of sulfide in the system was first confirmed by electrochemical techniques, while gravimetry was used to evaluate the effect of time and temperature on the inhibitive actions. SEM/EDX and XPS were used to characterize the corrosion product films on the steel surface. The behavior of sulfide was largely dependent on its concentration as its inhibition ability decreased with increasing concentration, and this is credited to the presence of FeS corrosion film layer. Time-dependent corrosion studies of steel conducted at 50 °C for the solution with 0.05 M and 0.1 M sulfide showed that the inhibition efficiency decreased from 89.1% and 75.0% to 82.4% and 68.6%, respectively, after 7 and 14 days immersion. At 80 °C, the inhibition efficiency of 0.05 M sulfide decreased from 89.1% to 48.9% after 7 days immersion and 82.4% to 46.1% after 14 days immersion. Together with FeS layer, FeCO3, Fe2O3 were also confirmed on the steel surface by XPS measurement. The research provides practical information on the influence of sulfide in the absorber and rich-lean heat exchanger sections of a CO2 capture unit.

Preparation, characterization, and corrosion inhibition performance of graphene oxide quantum dots for Q235 steel in 1 M hydrochloric acid solution

In the present work, graphene oxide quantum dots (GOQDs) prepared via electrochemical method was used as a liquid phase corrosion inhibitor. The structure and compositions of GOQDs were characterized by Fourier transform infra-red (FTIR) and X-ray photoelectron spectroscopy (XPS). The corrosion behavior of Q235 steel in 1 M hydrochloric acid solution in the absence and presence of different concentrations of GOQDs at different temperatures was investigated using weight loss and electrochemical measurements. The steel surface morphology was investigated with the implementation of XPS, scanning electron microscopy (SEM), and atomic force microscopy (AFM). It was found that the prepared GOQDs presented the best inhibition efficiency over 94%. The characterization studies revealed that prepared GOQDs contains functional groups such as carboxyl, hydroxyl, and aldehyde groups, which can spontaneously self-assembles on the metal surface to form adsorbed film, the adsorption isotherm showed that the adsorption process obeyed the Langmuir equation. The electrochemical polarization measurements demonstrated that GOQDs served as a mixed type inhibitor with the primarily inhibitive performance on anodic reaction, which is in well agreement with the adsorption free energy results.

Assessment on Corrosion Behavior of Q235 Steel in a Simulated Concrete Pore Liquid Containing Chloride by Electrochemical Noise

Assessment on Corrosion Behavior of Q235 Steel in a Simulated Concrete Pore Liquid Containing Chloride by Electrochemical Noise

Synergistic Effect Between Sulfate-reducing Bacteria and Pseudomonas Aeruginosa on Corrosion Behavior of Q235 Steel

Synergistic Effect Between Sulfate-reducing Bacteria and Pseudomonas Aeruginosa on Corrosion Behavior of Q235 Steel

Investigation of Corrosion Behavior of Q235 Steel in Simulated Industrial Wastewater

Investigation of Corrosion Behavior of Q235 Steel in Simulated Industrial Wastewater

Corrosion Behavior of Q235 Steel in Atmospheres Containing SO2 and NaCl

The atmospheric corrosion of metals is a severe problem in marine environments. However, the effects of SO2 and NaCl on the atmospheric corrosion of Q235 steel have not been widely studied. In the present work, electrochemical impedance spectroscopy was conducted to exploit the initial corrosion properties of Q235 in simulated atmospheric environments containing different contents of SO2 and NaCl. The solution resistance (Rs) and polarization resistance (Rp) of electrodes covered with pre-deposited NaCl were continuously monitored. The results showed that both SO2 and NaCl promoted the corrosion rate of Q235 steel. The pre-deposited NaCl maintained the moisture of the metal surface to ensure continued corrosion. The thickness of the electrolyte layer on the metal surface decreased with increasing SO2 content. A thin electrolyte layer could increase the Cl− concentration and reduce the pH value of the layer. The thin electrolyte layer could also promote the mass transfer of oxygen, thereby accelerating the cathodic reduction reaction. However, the NaCl content played a more important role than that of SO2 in the simulated environments.

Corrosion Behavior of Q235 Steel Exposed in Deepwater of South China Sea

For the first time, the corrosion behavior of Q235 steel in 1200, 2000 and 3000 m deepwater of South China Sea for 0.5 year was reported in this study. The corrosion morphology and corrosion products properties were investigated using different techniques, such as 3D optical microscope, scanning electron microscope, x-ray diffraction analyzer and electrochemical impedance spectroscopy. The main environmental factors influencing the corrosion rate of Q235 in deep sea were discussed by applying gray relational analysis. The results indicated that uniform thinning occurred after exposure. A large number of tiny pits were distributed under the corrosion products with a two-layer structure. The corrosion rate and average pitting depth of samples exposed at 2000 m were lower than those exposed at 1200 and 3000 m, and the main environmental factors determining the variation of corrosion rate at different depths were temperature and dissolved oxygen concentration. Hydrostatic pressure had slight effect on the corrosion rate of Q235 steel, but promoted the formation of a more uniform corrosion morphology.

Corrosion behavior of low-carbon Cr micro-alloyed steel for grounding grids in simulated acidic soil

To improve the corrosion resistance of steels for grounding grids, a low-carbon Cr micro-alloyed steel was developed (C1 steel), and corrosion behavior of Q235 steel and newly developed C1 steel in simulated acidic soil was investigated. The corrosion rate was evaluated with the mass loss measurements, while the corrosion morphology of surface and cross section of rust layer was observed by scanning electron microscopy. The corrosion products were analyzed by energy-dispersive X-ray spectrometry, X-ray diffraction and X-ray photoelectron spectroscopy, and the polarization curve was measured using potentiodynamic polarization method. Results indicated that C1 steel displayed good corrosion resistance in the simulated acidic soil, of which the corrosion rate was only 30% of that of Q235 steel after corrosion for 360 h. The analysis of rust layer showed that lower carbon content in steel could reduce the tendency of micro cell corrosion and appropriate amount of chromium could improve the corrosion potential of metal matrix. Moreover, the analysis of X-ray photoelectron spectroscopy revealed that the chromium enriched in inner rust layer of C1 steel existed mainly in the form of Fe2CrO4, which facilitated the formation of Cr-goethite and improved the protection of corrosion products.

Effect of pH Value on Corrosion Behavior of Q235 Steel in an Artificial Soil

Coupons of the grounding material Q235 steel were buried in an artificial soil of diato- mite with different pH values for 20 d, and then the corrosion behavior of the steel was examined. The results indicated that the pH value of the artificial soil had a great effect on the corrosion be- havior of Q235 steel. With the increasing of pH value, the corrosion rate of the steel in the artificial soil decreased, which accorded fairly well with that in the actual soil, correspondingly the corro- sion type of the coupons turned from rather serious uniform corrosion to slight local corrosion. The corrosion products formed in acidic artificial soil are consistent with those in an alkaline artificial soil, they all composed mainly of α-FeOOH, Fe3O4, γ-FeOOH and Fe2O3, however the products in the late case contained higher Fe3O4 and less α-FeOOH.

High temperature corrosion performance of Q235 steel in sulfur-bearing solution

The high temperature corrosion performance of Q235 steel in sulfur-bearing solutions as a function of temperature, test time, and sulfur content was investigated by weight loss measurements in this study. The results indicate that the corrosion behavior of Q235 steel in sulfur-bearing solution is directly related to the experimental temperature, immersion time and sulfur content. Higher temperature leads to a higher corrosion rate of the steel. The corrosion rate increases during the initial test time and then decreases with increasing the test time. As the sulfur content increases in the solution, the corrosion rate increases, and further increasing the sulfur content leads to a decreased corrosion rate.

Simulated Corrosion Test of Q235 Steel in Diatomite Soil

Through the study of the corrosion behavior of Q235 steel in actual Yingtan soil and two simulated acidic soils with different water contents, the calculation of corrosion mass losses, and the analysis of the corrosion morphologies and products by means of scanning electron microscope (SEM) and X-ray diffraction (XRD), the results demonstrated that the diatomite soil could simulate the corrosion in actual soil veritably. In both actual soil and simulated soil with 16. 4% water content, the corrosion rates of Q235 steel were approximately 0. 1 mm/a, the corrosion morphologies were mainly extension and connection of corrosion spots on sample surface, and the corrosion products were composed of α-FeOOH, γ-FeOOH, Fe3O4 and Fe2O3. When other media conditions remained unchanged, the corrosion area of Q235 steel was larger in simulated soil with 34. 5% water content, and the corrosion rate reached 0. 48 mm/a after 360 h of corrosion, which was nearly 5 times as the value in actual soil. Compared with the corrosion products in actual soil, the proportion of γ-FeOOH in simulated soil with 34. 5% water content was higher, and the wα-FeOOH/wγ-FeOOH ratio was 1. 4, which was only 1/3 of the value in actual soil.