Corrosion Specimens Research Articles

Mechanical Properties and Cooperation Mechanism of Corroded Steel Plates Retrofitted by Laser Cladding Additive Manufacturing under Tension.

As a metal additive manufacturing process, laser cladding (LC) is employed as a novel and beneficial repair technology for damaged steel structures. This study employed LC technology with 316 L stainless steel powder to repair locally corroded steel plates. The influences of interface slope and scanning pattern on the mechanical properties of repaired specimens were investigated through tensile tests and finite element analysis. By comparing the tensile properties of the repaired specimens with those of the intact and corroded specimens, the effectiveness of LC repair technology was assessed. An analysis of strain variations in the LC sheet and substrate during the load was carried out to obtain the cooperation mechanism between the LC sheet and substrate. The experimental results showed that the decrease in interface slope slightly improved the mechanical properties of repaired specimens. The repaired specimens have similar yield strength and ultimate strength to the intact specimens and better ductility as compared to the corroded specimen. The stress-strain curve of repaired specimens can be divided into four stages: elastic stage, substrate yield-LC sheet elastic stage, substrate hardening-LC sheet elastic stage, and plastic stage. These findings suggest that the LC technology with 316 L stainless steel powder is effective in repairing damaged steel plates in civil engineering structures and that an interface slope of 1:2.5 with the transverse scanning pattern is suitable for the repair process.

Mechanical responses of chemically corroded sandstone under cyclic disturbance: Insights from fatigue properties and macro-micro fracturing mechanism

Engineering rock masses are likely to be subjected to coupled chemical corrosion and cyclic load disturbance, deteriorating the internal structure of rocks and further threatening the long-term stability of engineering structures. In this study, to investigate the combined effect of cyclic loading and chemical corrosion, the cyclic uniaxial compression tests are conducted on sandstone specimens chemically corroded by different corrosion times (0, 20, 40, 60 days) and pH values (1, 3, 7, 11, 13). Our results indicate that chemically corroded sandstone specimens featured by an increase in irreversible strain and hysteresis energy density compared with natural rocks. A coupling damage variable is proposed to reflect the initial damage induced by chemical corrosion and the mechanical damage induced by cyclic disturbance, and the accumulation rate of coupled chemical-fatigue damage variables significantly increases with increasing corrosion time or enhancing acidity and alkalinity. Fatigue failure modes of tested specimens transform from splitting failure to unidirectional shear failure as corrosion time increases, and chemically corroded specimens are featured by ductile failure characteristics compared to natural state. Moreover, X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) are employed to analyze the micro-fracturing mechanism of sandstone. Cement minerals dominate the reactions in acidic solutions, whereas quartz takes the lead in alkaline conditions. Due to pronounced influence of cement minerals on the macroscopic mechanical properties of sandstone, acid corrosion specimens tend to experience more severe damage. Micro-cracks inside rocks under cyclic loading have sufficient time to pass through weakly bonded particles, and chemical reactions markedly weaken inter-particle bonding degree, and thus the fatigue fracture of chemically corroded specimens predominantly exhibits intergranular (IG) fracture.

Seismic response assessment of ductile reinforced concrete columns affected by corrosion and axial load variations

The present study investigates the effect of reinforcement corrosion and axial compression ratio (ACR) on the seismic response of large-scale ductile reinforced concrete (RC) columns. 3D numerical models of sound and corroded RC columns were developed and validated with detailed experimentation. Various parameters, such as hysteresis and backbone curves, stiffness degradation, ductility, and energy dissipation, were evaluated for all the specimens. The numerical findings were then compared with the experimental findings. Subsequently, a thorough parametric study was executed to analyse the structural behaviour under varying corrosion degrees and ACR level combinations. It was observed that both sound and corroded specimens experienced significant degradation in terms of their strength, deformability, stiffness, and ductility due to elevated ACR levels. Moreover, increased ACR levels in both specimen types led to a decline in pre-peak and post-peak response trajectories, resulting in an early achievement of peak response at lower drift levels. The study’s outcome advocates the significance of incorporating ACR levels into the design philosophy of ductile reinforcements for RC columns.

Stress concentration factor estimation for corroded steel plates using the surface gradient method

Pitting corrosion occurs in steel components as a stress-accumulating surface irregularity that is vulnerable to fatigue crack nucleation. In this study, stress distribution in sinusoidal surfaces was investigated to devise an estimation method for the stress concentration factor (SCF) fluctuations of corroded steel. An SCF equation for sinusoidal surfaces was developed from empirical data based on three parameters: wavelength, thickness, and position. For corroded surfaces, successive numerical differentiations can be performed on each point to determine the sinusoidal surface having a point sharing the same gradient information. Notably, the SCFs of corresponding points are comparable; SCF estimation is made feasible for irregular surfaces through sinusoidal surfaces. In two-dimensional sections, maximum error was below 5% at pits and 15% for the surface. In three-dimensional models, maximum error was below 20% at pits for wide-ranging corroded specimens. Therefore, the proposed method effectively estimates SCF for identifying areas at risk of fatigue cracking.

Experimental study on the axial compression behavior of circular steel tube short columns under coastal environmental corrosion

This study adopts experimental, numerical, and algorithmic methods to investigate the compressive behavior and failure mode of corroded circular steel tube short columns. The study establishes an equivalent relationship between electrochemical accelerated corrosion and natural coastal corrosion environments. The effects of current intensity, sodium chloride concentration, and energizing time on corrosion equivalent duration and mechanical properties of specimens are analyzed. The results demonstrate that the ultimate bearing capacity and energy absorption capacity of the specimens are significantly reduced with increasing current intensity and energized time. However, the NaCl concentration has minimal effect on the mechanical properties of the specimens. After natural corrosion in a coastal area with medium salinity for 19.2 years, the ultimate bearing capacity, ductility, initial stiffness, and energy absorption capacity of circular steel tube short columns decreased by 49.5 %, 63.1 %, 48.9 %, and 85.6 %, respectively. A novel corrosion pit generation algorithm is suggested to accurately simulate the distribution of corrosion pits and determine the ultimate bearing capacity of circular steel tube short columns. This algorithm demonstrates improved accuracy and stability compared to traditional simplified methods. Subsequently, a corrosion pit random generation model is developed using this method, and the accuracy of the finite element model is validated against experimental results. Furthermore, the impact of the diameter thickness ratio on the ultimate bearing capacity of corrosion specimens is thoroughly analyzed.

Study on Axial Compression Performance of Corroded Reinforced Concrete Columns Strengthened by Concrete Canvas and Carbon Fiber Reinforced Plastic under Secondary Corrosion

To investigate the effects of concrete canvas (CC) and carbon fiber reinforced plastic (CFRP) reinforcement on the mechanical properties of corroded reinforced concrete columns (compressive strength, flexure strength, strength of extension, and so on), 42 columns in four groups were designed and axial compression experiments were carried out. For the corroded reinforced concrete columns reinforced with CC and CFRP, the effects of initial corrosion rate (5%, 10%), secondary corrosion time (15 d, 30 d), number of CC layers (0, 1), and number of CFRP layers (1, 2, 3) on the failure morphology, load carrying capacity, and ductility of concrete columns were analyzed. The test results show that the properties of the single layer CC confined specimens are improved to a certain extent, and the ductility properties are enhanced. The properties of the CC–CFRP composite constrained specimens are greatly improved, the plastic deformation ability is enhanced, and the typical ductile damage characteristics are shown. The corrosion inhibition of CC for specimens with a theoretical corrosion rate lower than 20% showed an increasing trend, and the corrosion inhibition rate ranged from 23.0% to 31.2%. CC and CFRP restrain the concrete jointly, hindering the expansion inside the concrete, and the peak strain of the joint restraint specimen itself changes greatly, while the overall peak strain of the corrosion specimen is very small under the action of the joint steel bar. Finally, according to the existing peak stress–strain model and the experimental data in this paper, a peak stress–strain model suitable for corroded reinforced concrete columns is established. The established calculation model has a high accuracy, which provides a certain theoretical basis for subsequent research.

Hepatic portal vein branching patterns according to different liver assessment methods and classifications of branching type

BackgroundIt is known that there are varying frequencies of hepatic portal vein branching patterns found in the literature. Studies use different methods and classifications to evaluate the anatomy of the portal vein, which limits accurate comparison between studies and the determination of true frequency of branching patterns in different populations. The aim of the present study was to investigate the intrahepatic branching of the portal vein in corrosive samples using different methods – somatoscopic and computed tomography (CT) and compare with similar studies as well as compare the reclassified data according to the most popular classifications used in the literature. MethodsA total of 105 liver corrosion specimens from the 1960–1980 period (51 male and 54 female individuals; min-max age variation – 21–90 y., M=59,46 y.) were investigated. The branching patterns of the hepatic portal vein (HPV), left (HPV-LB) and right branch of hepatic portal vein (HPV-RB), and their segmental branches were examined and scanned by CT. Standard HPV ramification was considered, when HPV divided into HPV-LB and HPV-RB, HPV-RB bifurcated to the anterior and posterior branches, and further segmental ramification into the superior and inferior branches was considered standard. We compared the HPV main branch length and diameter measurements between manual and CT method. A review of the literature was performed on portal vein branching variations. ResultsThe standard HPV ramification pattern was detected in 85.7% of the cases in both somatoscopic and CT evaluation. Variations related to the main branches were HPV trifurcation – 7.6%, posterior branch of right branch of hepatic portal vein from HPV – 4.8% and 5.7%, HPV quadrifurcation 1.9% and 1% respectively, in somatoscopic and CT evaluation. There was a significant difference between HPV-LB length and diameter in CT and manual measurements. According to the literature, more variations are seen using the CT method versus somatoscopic corrosion cast evaluation. The varying frequency in studies may be explained by a lack of one unanimous classification of branching patterns (some authors do not consider segmental variations as standard HPV ramification) and different evaluation methods. ConclusionSomatoscopic evaluation of the branching patterns of the hepatic portal vein in corroded specimens and their CT reconstructions did not differ significantly (which allows relatively accurate comparison of old specimens with newer data). However, the ability to evaluate the reconstructed 3D images of the specimens allowed a more accurate assessment of segmental branching and measurements of lengths and diameters. Standard HPV branching (according to a self-developed classification) in this study was 85.7%. Depending on the classification, the rate of standard branching in the same corrosive samples varied from 63.8% to 84.8% of all cases, indicating that the lack of a unified and stable classification makes it difficult to compare the results of different studies. Deviations from standard branching are very important in surgical procedures and liver transplantation.

Fatigue Life Prediction of High Strength Steel with Pitting Corrosion under Three-Point Bending Load

Offshore structures often suffer from pitting corrosion, which leads to local stress concentrations, a decrease in the cross-sectional area, the subsequent initiation and gradual propagation of cracks, and a shorter service life as a result. This study aims to investigate the impact of pitting corrosion on the fatigue life endurance of high-strength steel used for offshore structures. To this end, a three-point bending fatigue test was first performed on the specimens to obtain the fatigue test data. Then, a fatigue life prediction model consisting of two terms is proposed based on fracture mechanics, and the fatigue test data are used to verify the reliability of the model. Finally, the experimental results are discussed, and conclusions are drawn. The first term was designed for crack initiation. Combining with the energy theory and slip band dislocation theory, a novel equivalent surface defect model was proposed and used to predict the fatigue life of pitted corroded specimens before crack initiation. The second term is designed for crack propagation. The generalized Paris model is adopted for fatigue life prediction during the crack propagation process after the crack angle is taken as a variable. The mathematical model for predicting three-point bending fatigue life was finally obtained, and the average relative error of the data validation results did not exceed 16%, which proved the reliability of the prediction model.

The Effects of Corrosion and Fire Damage on the Steel-Bolted T-Section Connections Used in the Steel Construction.

The most common type of connection in steel structures is the T-section connection. Steel structures can be damaged due to environmental effects such as earthquakes, fires, corrosion, etc., in real applications used in industry. Therefore, in this study, the corrosion and fire condition effects that occur in the T-section connection on the behavior of the connection zone were investigated. The study was carried out with 18 T-section connections with various corrosion (hydrochloric acid and sulfuric acid) in different layers at 5, 10, 15, and 20% corrosion levels, and fire (ISO834) conditions after corrosion have been evaluated and compared. T-section-bolted joints examined in the study were produced using IPE300 standard profiles. In the first part of the study, the behavior of the 18 T-section connections under an axial tensile load has been determined experimentally. The second part created a finite element model with the ABAQUS program for all models. It was seen that the finite element model analysis results converged with the results obtained as a result of the experimental study. As a result, compared to H2SO4 corrosion, HCl corrosion has little effect on the load-deformation characteristics of the connections. Also, if corrosion specimens are exposed to fire, then the connections will change from semirigid to hinged.

Residual Bond Strength of Highly Corroded Reinforced Concrete

Corrosion of reinforcement due to chloride attacks in the marine environment is a natural phenomenon. Corrosion of reinforcement produces corrosion products of high volume, which deteriorates the structural integrity of reinforced concrete structures due to loss of bond, cracking, and spalling of the concrete. Existing literature has documented tests investigating the bond behavior of uncorroded and corroded specimens, but there is a dearth of data pertaining to a more advanced stage (higher mass loss) of corrosion. In the current study, an accelerated corrosion test was conducted on cylindrical (lollypop) specimens, which involved utilizing an impressed current laboratory technique to induce three distinct levels of corrosion (10%, 20%, and 40% mass loss). Moreover, to assess bond strength, the pull-out tests were performed on both corroded and uncorroded specimens. The present study deals with the residual bond strength at three different corrosion levels, as a function of different parameters such as clear cover (CC), water-cement (W/C) ratio, and two different reinforcement diameters. Experimental data reveals that the mass loss achieved is lesser than the target mass loss for all specimens. It is observed that at higher corrosion levels, where the mass loss exceeds 10% or cracks appear on the surface of the reinforced structure, both an increase in mass loss and a decrease in residual bond strength is consistently observed. These effects remain consistent regardless of whether the parameters such as bar diameter, W/C ratio, and CC are increased or decreased. The statistical analysis was performed on the experimental data to develop predictive models for estimating the residual bond strength and mass loss. For higher mass loss of 30% to 35%, the corresponding bond strength for all of the specimens falls within the range of 4 Mpa to 6 MPa.

Correlation of Accelerated Corrosion and Real Reinforced Concrete Water Structures

The service life of reinforced concrete constitutes the initiation and propagation period. Accelerated corrosion tests are carried out to obtain results in modelling the Service life of reinforced concrete structures. Its erroneous to undertake a direct linear extrapolation of accelerated test results to real structures in predicting their service life. This research examines the relationship between the result from accelerated corrosion and real reinforced concrete water structures. The physical and chemical properties of the materials used in the study were investigated for compliance for use in reinforced concrete water structures. Concrete of three classes M25, M30 and M35 were used to cast accelerated corrosion test samples. For each class 9 concrete samples of diameter 100 mm,130 mm and 150mm respectively and 300mm long were prepared. A 10 mm diameter bar,400mm long was centrally inserted during casting. After curing the test samples were immersed in a 3.5% solution of sodium chloride solution under 6 V. The accelerated corrosion specimens were monitored for onset of cracks and stopped when the cracks were 0.2 mm in width. Using the accelerated corrosion and real reinforced concrete results, a parametric study of the propagation period was done and a model proposed. From the results the proposed and published propagation period model compares well. The result from accelerated corrosion and real reinforced concrete water structures lineally increase for the propagation period. The proposed model can be considered as an input parameter for the service life of actual reinforced concrete water structures and contribute to their optimum performance.

Theoretical and experimental study on the effect of stress corrosion on magnetic flux leakage signals

Stress corrosion is widespread in engineering materials, which seriously threatens the bearing capacity of the structures. The current study aims to establish a Corrosion-Stress-Magnetic coupling model based on weak magnetic detection technology. This paper proposes a uniform plane current model under stress corrosion by analyzing the corrosion mechanism, and the magnetic field generated by the corrosion current is obtained. The Corrosion-Stress-Magnetic coupling model is established based on the magnetic memory method. Then the Magnetic Flux Leakage (MFL) signals of whole uniform stress corrosion specimens are studied experimentally and theoretically. Particularly, the experimental values of the changes in the slope of the normal MFL component and the amplitude of the tangential MFL component are consistent with the computational values, which indicates that the proposed model is correct and effective in predicting the effect of stress corrosion on the magnetization of a specimen.

Quantitative Evaluation of Corrosion Defects on Structural Steel Plates via Metal Magnetic Memory Method

ABSTRACT The detection and evaluation of corrosion defects take on a critical significance to ensure the service safety of steel structures in civil engineering. The quantitative evaluation of corrosion defects has not been well addressed though metal magnetic memory (MMM) testing technology has been investigated in steel corrosion problems. In this study, the Q345qD steel plates were taken as the specimens of MMM testing. Specimens with different corrosion degrees were developed through electrochemical corrosion, and the change laws of the MMM signals and the characteristics of different corrosion specimens were analyzed. A three-dimensional (3D) magnetic charge model of the corrosion area was built based on the magnetic charge theory, such that the change laws of the MMM signal in the corrosion area from the mechanism were explained. The finite element simulation results of the corrosion specimens were well consistent with the experimental and theoretical results. A quantitative evaluation method for corrosion defect depth was proposed in combination with finite element simulation and experimental data. Comparing the experimental data and the inversion data, the relative errors of the determined defect depth h were within 20%, suggesting that the proposed evaluation method is feasible for the quantitative evaluation of steel corrosion depth.

Effect of burnishing on HVOF coated boiler steel against hot corrosion in actual boiler environment

ABSTRACT Hot corrosion of boiler tubes used in steam-generating systems has been recognized as a severe problem, resulting in tube wall thinning and premature failure. In this study, the effect of burnishing the thermal sprayed coatings against high-temperature corrosion of SA213-T22 boiler steel in actual environmental conditions of coal-fired boiler has been investigated. An experimental study was carried out for ten cycles, where the individual cycle consists of one-hundred hours of exposure trailed by one hour of ambient cooling. The hot corroded specimens are visually inspected at the end of each cycle to check for any variation in colour, luster, spalling tendency, and other physical changes in scale. The tested specimens were characterized through Thermogravimetric Technique, Microhardness Tester, Optical Microscope, Scanning Electron Microscope, and X-Ray Diffractometer to study their hot corrosion performance. The findings of this work suggest that burnishing can be potentially used for providing superior hot corrosion protection to any of the thermal sprayed coated specimens.

Corrosion-Effected Bond Behavior between PVA-Fiber-Reinforced Concrete and Steel Rebar under Chloride Environment

Corrosion-effected bond behavior between polyvinyl-alcohol-fiber-reinforced concrete and steel rebar under a chloride environment is the experimental subject studied in the present work. Twenty-four pull-out specimens are designed and subjected firstly to an accelerated corrosion test. The effects of polyvinyl alcohol fibers on the cracking behavior, chloride penetration of concrete members and the corrosion loss of steel rebars during the corrosion test are discussed. After this, these corroded specimens are subjected to a pull-out test. The failure mode, the bond-slip curves and the typical bond-stress values are measured during the test. The effects of polyvinyl alcohol fibers and corrosion loss on bond behavior between polyvinyl-alcohol-fiber-reinforced concrete and steel rebar are clarified. Results show that the polyvinyl-alcohol-fiber-reinforced concrete exhibits worse resistance to corrosion damage than plain concrete. The cracking width, chloride penetration depth in concrete and the corrosion loss of steel rebar are more serious for the specimens with more polyvinyl alcohol fibers. The polyvinyl alcohol fibers also negatively affect bonding in ascending branches for both the specimens, but improve the bonding in descending branches after peak stress in the case of splitting. In the present test, the bond strength of corrosive specimens is increased slightly and then decreases gradually with the deepening of corrosion loss. The failures of specimens change from pull-out to splitting-pull-out as the corrosion time exceeds 30 days. Compared with uncorroded specimens, the maximum degradation of bond strength is about 50.1% when the corrosion is increased from 0% to 15%.

Behavior of corrosion damaged non-seismically and seismically detailed reinforced concrete beam-column sub-assemblages under cyclic loading

Corrosion of reinforcement requires immediate redressal as it poses a severe threat to the serviceability and seismic performance of the existing reinforced concrete structure. Taking this into consideration, the current study presents an experimental assessment of the seismic behavior of corroded exterior beam-column joint sub-assemblage under quasi-static reverse-cyclic loading. A total of eight exterior beam-column joint specimens i.e., four having traditional non-ductile transverse reinforcement detailing as per IS 456:2000 and the remaining specimens ductile detailed according to IS 13920:2016 were cast. One specimen from each detailing regime was tested uncorroded and acted as a control specimen while the remaining six specimens were subjected to varying levels of accelerated corrosion. The experimental results illustrated that the sliding phenomenon in the hysteresis curve gradually increases and a drastic fall in energy dissipation, stiffness, and post-yield displacement were seen as the corrosion progresses within reinforcing bars. The failure mode shifted from diagonal joint shear failure observed in control specimens to longitudinal and major flexural cracking failure along the beam reinforcement. First-level corroded specimens showed a slightly increased ductility factor, indicating that low levels of corrosion may improve ductility. However, after 10% corrosion, all corroded specimens showed poor seismic performance and the cumulative energy dissipation curve tends to go flat at approximately half the displacement as compared to control specimens. The cumulative energy dissipation of non-ductile and ductile specimens damaged to the most severe level of corrosion in this study was only 0.3 and 0.4 times that of respective control specimens. In general, the ductile detailed specimens showed better seismic performance than the corresponding non-ductile detailed specimens owing to the closer arrangement of stirrups.

Seismic Retrofit of Nonuniformly Corroded Coastal Bridge Piers with FRP and Engineered Cementitious Composite Overlays

Coastal bridge piers are prone to corrosion attack owing to their exposure to marine environments, particularly in the splash and tidal zone, which is rich in chloride, oxygen, and moisture. Severe corrosion in this area results in the transfer of plastic hinges and evidently impairs the structural performance under seismic loading. Previous seismic retrofitting typically focused on the area of the pier end with the greatest bending moment. However, the location of the splash and tidal zone varies with the change in season and is generally not in the pier end. This study investigated for the first time the seismic retrofit of such piers using fiber-reinforced polymer (FRP) and engineered cementitious composite (ECC), where the middle part of the pier subjected to NaCl solution corrosion was simulated as the splash and tidal zone. Reversed cyclic loading tests of nine bridge piers with various corrosion rates, FRP types, and retrofit areas were performed. The seismic behaviors in terms of failure mode, crack pattern, load-carrying capacity, ductility, energy dissipation capacity, and stiffness degradation were compared and discussed. The experimental results of mildly corroded specimens indicated that seismic retrofitting with combined FRP and ECC significantly improved the seismic performance of bridge piers. The retrofitted specimen exhibited an even higher ductility and energy dissipation capacity than the noncorroded specimen. For severely corroded piers, the plastic hinge was transferred from the pier end to the corroded area and then transferred back to the pier end after retrofitting. The seismic performance of the specimens retrofitted from the corroded area to the foundation was better than that of the piers retrofitted only in the corroded area.

電磁超音波共鳴法による腐食減肉試験片の肉厚計測精度向上のための信号処理法の検討

電磁超音波共鳴法による腐食減肉試験片の肉厚計測精度向上のための信号処理法の検討

Degradation Behavior of the Preload Force of High-Strength Bolts after Corrosion

Corrosion significantly affects the structural behavior of members in a connection (i.e., the thickness of steel plates, the preload force of bolts, and the friction factor of steel plates). Safety assessment of corroded steel frames (i.e., beam-to-column connection, beams, or columns) has been a major concern in engineering. In this work, an experiment of accelerated corrosion testing is carried out to obtain corroded specimens connected with high-strength bolts, and the preload force of high-strength bolts (PF-HSB) is monitored throughout the whole stage of the corrosion testing. Before the corrosion testing, the PF-HSB caused by the stress relaxation is also recorded. The PF-HSB decreases rapidly in the first five hours after the final screwing of bolts and it keeps stable after 100 h. The PF-HSB is seriously affected by corrosion, which decreases by 30.0% of the original preload force when the corrosion rate of steel plate reaches 3.5%. A finite element method for predicting the PF-HSB after corrosion is proposed. An estimation model for the PF-HSB considering the stress relaxation is established. A degradation model for predicting the PF-HSB after corrosion is also suggested, and is in good agreement with experimental data. The results of this research are of great significance for the safety assessment of in-service steel structures.

Synergism of alkylbenzene sulfonate and cetyltrimethylammonium bromide on corrosion inhibition of carbon steel in CO2 -saturated solutions

The synergistic effect of mixed surfactants, linear alkylbenzene sulfonate (LAS) and cetyltrimethylammonium bromide (CTAB), in inhibiting corrosion of CO2 on carbon steel was studied by weight loss and electrochemical measurement. The surface properties of LAS, CTAB, and their mixture in solution were also studied by surface tension and phase behavior. The surface of corrosion specimens was characterized by infrared spectroscopy, scanning electron microscopy, contact angle, and atomic force microscopy. The results show that LAS, CTAB, and their mixture are inhibitors mainly inhibiting anode reactions. The adsorption of LAS and CTAB molecules on the surface of steel belongs to chemical adsorption and follows Temkin adsorption. LAS or CTAB alone aggregated form spherical micelles or rod-like micelles, which results in the defective film layer and localized corrosion on surface of the steel. Mixed surfactants form closely packed lamellar microstructure in the solution which is correlated to compact adsorption film on the metal surface and better corrosion inhibition. The inhibition efficiency is the highest when the mixed ratio of LAS and CTAB is 2:1.