Cold-rolled Low-carbon Steel Research Articles

Effect of strain path and short-term post-annealing on the microstructure, texture, and mechanical anisotropy of low-carbon steel

In this research, the effect of strain path and short-term post-annealing on the microstructure, texture, and mechanical anisotropy of low-carbon steel was investigated. Asymmetric unidirectional rolling (AUR) and asymmetric cross rolling (ACR) were applied on Fe-0.072C steel. The ACR-processed sheet revealed a very limited number of new grains compared to the AUR-processed sheet, which was due to the dynamic recovery induced by strain path change. The average ferrite grain size of the post-annealed AUR- and ACR-processed samples was 11.5 and 14.1 μm, respectively. The dominant recrystallization in the annealed AUR-processed sheet was discontinuous static recrystallization, while that in the annealed ACR-processed sheet was continuous static recrystallization. The weak typical rolling textures (γ-fiber and α-fiber) at the midthickness of both rolled sheets demonstrated that the shear deformation effectively contributed to the formation of the shear textures during asymmetric cold rolling. The ACR decreased the intensity of the overall texture more than the AUR process due to the changes in the reference frame of deformation after each pass, which destabilized ideal texture components. The results showed that Goss and {111}〈112〉 components were continuous and discontinuous static recrystallization textures in the asymmetrically cold-rolled low-carbon steel sheet during the annealing treatment, respectively. The annealed AUR-processed sheet revealed a weaker texture as compared to the annealed ACR-processed sheet. The significant changes in the preferred orientations of the annealed AUR-processed sample led to weaker texture intensity compared to the annealed ACR-processed sheet. The hardness of the annealed AUR-processed sheet (183.8 HV) was higher than that of the annealed ACR-processed steel (156.9 HV), which was owing to the larger grain size and also the elimination of the γ-fiber texture in the annealed ACR-processed sheet. The strength along the rolling direction was lower than that along the transverse direction in the AUR-processed sheet. However, in the ACR-processed sheet, the values of strength were similar along three different tensile directions. As an important conclusion, if both high-strength and low-anisotropy are needed in the low-carbon steel sheets, it's better to apply ACR rather than AUR. In addition, if both high toughness and low anisotropy are essential, it's better to use AUR followed by post-annealing rather than ACR + post-annealing. The length of the intermediate stage of work hardening in the annealed ACR-processed sample was much less than the annealed AUR-processed sheet due to the presence of harder orientations (〈111〉 and 〈110〉) along rolling and transverse directions in the annealed ACR-processed sample. Finally, the fracture behavior of deformed and post-annealed steel sheets for both strain paths was ductile and shear ductile.

Friction stir spot welding of cold-rolled low carbon steel plates using TiC0.5N0.5–Xwt%W (X=70, 72, 75) cermet tool specimens

Friction stir spot welding (FSSW) tests of steel plate cold commercial (SPCC) cold-rolled low-carbon steel plates with a thickness of 1 mm were conducted using TiC0.5N0.5–X wt% W (X = 70, 72, 75) cermet tool specimens with Ti(C, N) core–(Ti, W)(C, N) rim structures and the W–based alloy phase. All of the TiC0.5N0.5–X wt% W cermet tool specimens were prepared by the spark plasma sintering of blended TiC0.5N0.5 and W submicron powders. The SPCC steel plates could be welded more than 2000 times using a TiC0.5N0.5–72 wt% W cermet tool specimen, whereas it has been reported that the steel plates could be welded approximately 1000 times using a commercially available Si3N4 tool specimen. Both the upper and lower steel plates after the 6th, 1006th, 1506th, and 2006th welding using the TiC0.5N0.5–72 wt% W cermet tool specimen were joined together without any voids or cracks. The SPCC steel plate specimens after the 1003rd, 1503rd, and 2003rd welding using the TiC0.5N0.5–72 wt% W tool specimen were considerably bent near the joint during the tensile shear test, indicating that the bonding strengths of the plate specimens were at least as high as the yield stress of the untreated SPCC steel plates.

Effect of Electrical Resistance Heating on Recrystallization of Cold-Rolled Low-Carbon Steel

The “electron wind effect” has long been cited as a potential catalyst of solid-state transformations in metals, particularly when high current densities are involved. However, the literature exploring similar effects at lower current densities, such as those occurring during Gleeble thermomechanical simulation, remains scarce. The present work compares recrystallization activity in cold-rolled low-carbon steel during heat treatment by conventional furnace versus direct resistance heating (Gleeble). Multiple levels of cold work, annealing durations, and soak temperatures were examined, allowing for an in-depth comparison of recrystallization rates and activation energies between samples subjected to identical time–temperature profiles in the furnace and Gleeble. In addition to the expected increase in recrystallization behavior with the increases in temperature and cold-reduction levels, the use of the Gleeble system as the heating method resulted in faster initial microstructural transformation than a conventional furnace. The variability in recrystallized fractions persisted until the microstructures had saturated to their nearly fully recrystallized levels, at which point the microhardness and electron backscatter diffraction (EBSD) revealed convergence to equivalent behavior irrespective of the heating method. Analysis of the recrystallization kinetics by fitting to a JMAK relationship reflected the increased transformation activity during Gleeble treatment, with the value of the kinetic exponent also indicating greater grain growth activity at higher temperature.

An Investigation into the Friction of Cold-Rolled Low-Carbon DC06 Steel Sheets in Sheet Metal Forming Using Radial Basis Function Neural Networks

This article presents the friction test results for cold-rolled low-carbon DC06 steel sheets, which are commonly processed into finished products using sheet metal forming methods. A strip drawing test with flat dies was used in the experimental tests. The strip-drawing test is used to model the friction phenomena in the flange area of the drawpiece. The tests were carried out using a tester that enabled lubrication with a pressurised lubricant. The friction tests were carried out at different nominal pressures, oil pressures, and friction conditions (dry friction and oil lubrication). Oils destined for deep-drawing operations were used as lubricants. Neural networks with radial base functions (RBFs) were used to explore the influence of individual friction parameters on the value of the coefficient of friction (COF). Under lubrication with both oils considered, the value of the COF increased with decreasing oil pressure. This confirms the correctness of the concept of the device for reducing friction in the flange area of the drawpiece. The developed concept of pressurised lubrication is most effective at relatively small nominal pressures of 2–4 MPa. This range of nominal pressures corresponds to the actual nip pressures when forming deep-drawing steel sheets. Under conditions of dry friction, the values obtained for the COF rise above 0.3, while under lubrication conditions, even without pressure-assisted lubrication, the COF does not exceed 0.2. As the nominal pressure increases, the effectiveness of the lubrication exponentially decreases. It was found that the Sq parameter carries the most information regarding the value of the COF. The RBF neural network with nine neurons in the hidden layer (RBF-8-9-1) and containing the Sq parameter as the input was characterised by an R2 of 0.989 and an error of 0.000292 for the testing set.

Effect of ultra-fast heating on microstructure and mechanical properties of cold-rolled low-carbon low-alloy Q&P steels with different austenitizing temperature

We performed ultra-fast heating (150 °C/s) quenching and partitioning (Q&P) processes to a cold-rolled low-carbon low-alloy steel. Adjusting the annealing temperature, we obtained two types of ferrite-containing Q&P steels with different matrix structure, i.e., martensitic matrix and ferritic matrix. The effect of ultra-fast heating on microstructure evolution and mechanical properties was analyzed, compared with the samples treated with conventional heating rate (10 °C/s). We also investigated the strain partition and fracture behaviors, basing on in-situ tensile tests under SEM. Results show that ultra-fast heating can significantly increase the A c1 and A c3 temperatures, and extend the temperature span of intercritical zone. It can also delay the complete recrystallization of deformed ferrite and promote the austenite nucleation, which leads to the structure refinement of the sample with martensitic matrix, improving both the strength and ductility. The increase of austenite nucleation rate and the incomplete recrystallization of deformed ferrite jointly promote the austenite transformation, which results in a distinct increase of martensite islands fraction in the sample with ferritic matrix, leading to its obvious increase of tensile strength and decrease of ductility. Strain partition is an important factor affecting the TRIP effect in ferrite-containing Q&P steels. For the sample with a martensitic matrix, retained austenite mainly possesses a film-like morphology and exists between martensite laths. The relatively high mechanical stability of retained austenite films and low local strain in martensitic regions result in the weak TRIP effect. The retained austenite in the sample with a ferritic matrix mainly distributes among ferrite grains and exhibits a blocky morphology. The relatively low mechanical stability of blocky retained austenite and high local strain in ferrite jointly enhance the TRIP effect. • Ultra-fast heating delays ferrite recrystallization. • Ultra-fast heating restrains martensite tempering. • Ultra-fast heating results in grain refinement of martensitic matrix. • Strain partition is a crucial factor controlling TRIP effect. • Main ductility origin is compatible deformation of matrix structures.

Influence of non-metallic inclusions on the corrosion resistance of cold-rolled low-carbon steels microalloyed with titanium

Influence of non-metallic inclusions on the corrosion resistance of cold-rolled low-carbon steels microalloyed with titanium

КРАТНОМАСШТАБНЫЙ ВЕЙВЛЕТ-АНАЛИЗ ПРОФИЛОГРАММЫ

The functional properties of the surface are significantly affected by its microgeometry, therefore it is necessary to optimize the parameters of the microgeometry of the surface of metal structures. The analysis and evaluation of the microgeometry of the surface allows an assessment of the fatigue strength of metal structures. In order to study the dependence of the durability of thin-sheet structures on the degree of corrosion destruction, the microgeometry of the surface was analyzed using a profilometer 130 in accordance with GOST 25142-82. Low-carbon cold-rolled steel 08kp was used as the test material. The surface roughness of the samples was Ra = 0.22 microns. The roughness parameters were calculated according to GOST 2789-73. A profilogram representing a discrete series of values of peaks and troughs of the relief of the metal plate surface was studied. To assess the microgeometry of the surface, a wavelet analysis was used, which allows processing signals that are nonstationary in time or inhomogeneous in space. The signal in the form of successive approximations has a trend, cyclic components and local features (fluctuations) around the components of the signal. The locality property of wavelets gives advantages over the trigonometric Fourier transform: the sines and cosines are defined on the entire numerical axis, and the wavelets have a compact carrier. For multiscale analysis, a fast cascade algorithm of calculations has been developed by analogy with the fast Fourier transform. In the study, the signal was decomposed to the 9th level. The reconstructed detailing coefficients represent high-frequency and low-frequency fluctuations. The decomposition of the signal to the 9th level made it possible to analyze the surface roughness of the 08kp steel using a multiple-scale wavelet analysis.

Interplay of Nb addition and annealing temperature and its influence on microstructure and tensile properties of multiphase steel

We investigated the interplay of Nb addition and annealing temperature and its influence on the microstructure evolution in low carbon cold-rolled steel to understand the unique change of tensile properties derived by Nb addition. While the Nb addition exerted the strengthening effect led by the ferrite grain refinement and tiny NbC precipitation, the characteristic change in the soft and hard phase fractions made the overall influence of Nb addition complicated. The Nb addition was leaving considerable amount of non-recrystallized ferrite when annealed at 770 °C, contributing remarkable strength enhancement. However, after annealing at 850 °C, where the initial microstructure completely transformed into austenite, the Nb addition promoted the decomposition of austenite into new ferrite upon subsequent cooling. It led to the increase of soft phase fraction in the final microstructure with the annealing temperature, compensating for the hardening effect by the grain refinement and NbC precipitation. Consequently, the yield and tensile strength was decreased with the annealing temperature in the Nb-added steel, which was opposite to that in Nb-free steel.

Increasing technological plasticity with preserving strength of cold-rolled thin-sheet low-carbon steel

At domestic metallurgical plants, the traditional method of softening low-sheet cold-rolled low-carbon steels is long recrystallization annealing of coils in cap furnaces, which has significant disadvantages: the process is very long and energy-consuming. According to the properties of annealed steel, it does not meet the requirements of the consumer for the manufacture of two-layer rolled brazed tubes. In this regard, the question of developing a new method of weakening heat treatment of cold-rolled sheet to improve the set of properties and the quality of the sheet surface is relevant in time and has unconditional practical significance with the prevention of its deformation aging. To achieve this goal the following tasks were solved: research and determination of optimal temperature-time parameters of high-speed contact recrystallization annealing and subsequent aging (which has no analogues) of thin tape blanks to obtain a given set of performance properties and prevention of natural aging. The best mode of contact high-speed (100 0 C / c) recrystallization annealing is established, which provides cold-rolled sheet steel 08 kp with a set of properties that corresponds to GOST 9045-93 category VG, i.e. the ability of steel to cold complex deformation. However, further deformation aging of annealed steel at a speed of 08 kp leads to a sharp drop in ductility and increased strength. Developed a two-stage softening high-speed heat treatment consisting of recrystallization annealing and subsequent aging, increases both the strength and ductility of cold-rolled sheet, stabilizes the properties of steel to prevent its deformation aging. The obtained properties meet the regulated requirements of the consumer to the blanks intended for production of the two-layer rolled up soldered tubes operated in the conditions of the increased pressure. Tubes of small diameter, which were made of steel strips, processed by the recommended technology, have successfully passed 100 % defect-free quality control in the production environment.

Grain Size Distribution Law of Cold-rolled Low-carbon Steel with Various Holding Temperatures

With the cold-rolled low-carbon steel sheet produced by CSP process as the object of study, uniformity of microstructure and grain size distribution law of “pancake” (elongated) grains were investigated. The samples were annealed under laboratory condition to simulate batch annealing processes with holding temperatures from 660 °C to 700 °C. Conclusions are drawn that the grain size distribution of annealed test steel along both the rolling direction and the thickness direction of the sheet samples accords well with the law described by the Log-normal function.

Epilamization of surface as a way to plasticize cold-rolled low carbon steel

Abstract. About 60 % of automobile and 40 % of tractor parts of various shapes and sizes are made from cold-rolled thin-sheet low-carbon steel by cold stamping. Automatic cutting lines for rolled sheet steel into blanks for stamping and automatic presses for the manufacture of deep-drawn parts of complex geometric shapes from a sheet result in increased demands on the quality of the metal: high technological ductility in order to improve stampability and obtain the required degree of deformation without fracture and ensuring sufficient strength after stamping to reduce weight, fuel economy and vehicle safety. In this regard, the search for new technological solutions relevant to ensure these conflicting requirements for the consumer properties of steel sheets is relevant. According to modern concepts, an approach that determines the influence of a thin surface layer on the deformation behavior and formation of product properties is promising for solving this problem. In this paper, we propose a method for significant improving of formability while maintaining the strength of low-carbon cold-rolled sheet steel by changing the state of the surface by epilating (EP). It is established that EP significantly reduces surface roughness, heals surface defects and significantly plasticizes the product, which greatly improves the stampability of 08кп steel blanks. Estimated by the Ereksen method, the ability of a sheet of 08kp steel to be drawn varies from the high-temperature group to values exceeding the requirements of WWTP, which according to GOST 9045-93 are regulated only for the best quality steel 08Yu. At the same time, sheet strength and resistance to brittle fracture increased. This effect has been obtained for the first time and is fixed by a patent for the invention.

Influence of annealing temperatures on microstructure evolution and mechanical properties in a low-carbon steel

Quenching and partitioning (Q&P) heat treatments with different annealing temperatures and fixed initial quenching temperatures were applied to cold-rolled low-carbon steel with the initial microstructure of ferrite and pearlite, aiming to gain the same amount of austenite (preset value) before the partitioning stage. The chemical compositions of the material have been specially designed, containing 1.6 wt.% silicon and 0.8 wt.% aluminum to avoid the precipitation of carbides. The microstructure evolution of the investigated steel was characterized using a dilatometer, an optical microscope, a scanning electron microscope (SEM), an X-ray diffractometer, an electron backscattered diffraction and transmission electron microscope. Consequently, the microstructure of all samples looks quite similar. At the same time, according to SEM micrographs and dilatometer data, there are competitive reactions in Q&P process, such as the precipitation of carbides, the transformation of bainite and the formation of secondary martensite. Thus, the measured austenite is less than the preset values. Mechanical properties of the material were detected by uniaxial tensile tests. The results indicate that the ultimate tensile strength of the four groups of samples is similar, but the total elongation has a significant downward tendency with the increase in annealing temperatures. After annealing at 840 °C, the steel possesses great ultimate tensile strength of about 1200 MPa and optimum total elongation of about 20.37% with favorable products of strength and elongation of about 24.35 GPa%.

Internal Friction Study of the Bake-Hardening Properties on Low Carbon Steel Influenced by the Degree of Pre-Deformation

This paper selected cold-rolled low carbon steel as the object of experimentation to better understand that the annealed sample was baked in different degree of pre-deformation span to measure its baking hardening property. The main results of the experiments are as follows: The sample was set in different pre-deformation. Firstly, the baking temperature was set as 170°C and the time span was 20 minutes. The results released that when the degree of pre-deformation was set between 2% and 5%, the BH value increased with the increasing degree of pre-deformation. Secondly, the degree of pre-deformation was set between 5% and 10%, the BH value decreased with the increasing degree of pre-deformation. Thirdly, when the degree of pre-deformation was set at 5%, the BH value reached the maximum. It is illustrated that the BH value increased along with the rising of SKK peak while decreased with the falling of SKK peak. It indicated that the increase of the BH value was mainly due to the intensification of the Cottrell Atmosphere. As the pre-deformation increased, the sum of hSnoek+hSKK decreased. It is worth noting that while under the same circumstances, the sum of hSnoek+hSKK increased after baking.

An innovative pathway to produce high-performance quenching and partitioning steel through ultra-fast full austenitization annealing

Quenching and partitioning (Q&P) treatment was conducted on a cold-rolled low-carbon steel using a quenching dilatometer. A novel phase-transformation pathway to produce high-performance Q&P steel by introducing fast-heating full austenitization annealing method was proposed in the present work. Different from conventional slow-heating intercritical annealing (4 K/s), an unexpected transition from austenite to ferrite occurs even upon rapid cooling (70 K/s) through ultra-fast full austenitization (300 K/s) annealing, corresponding to unstable carbon-depleted austenite. Ultra-fine high-carbon austenite retards the martensitic transformation to lower temperature regime upon further cooling, and lath-like martensite forms owing to the pinning effect from prior ferrite and ultra-fine austenite grain boundaries. Mechanical properties demonstrated that the full austenitization annealing method could enhance both the slow-heating QP-4 and fast-heating QP-300 samples from 980 MPa grade to a higher grade (1180 MPa) Q&P steel, and meanwhile, it should be noted that the total elongation up to 21.7 % was obtained for the QP-300 samples, higher than 16.5 % of the QP-4 samples. Although the yield strength of QP-300 samples slightly decreased, the product of strength and ductility strikingly improved from 19.5 GPa% to 25.7 GPa%.

Correlative analysis of interaction between recrystallization and precipitation during sub-critical annealing of cold-rolled low-carbon V and Ti–V bearing microalloyed steels

In this paper a new insight into fundamentals of static recrystallization, precipitation and their interaction during sub-critical annealing of three cold-rolled low-carbon microalloyed steel grades is presented. The grades under investigation are a base grade containing V as a microalloying element, a Ti + grade containing Ti as microalloying element added into the base grade, and a Ti + Mn + grade containing additional Mn added into the Ti + grade. The cold-rolled steels are sub-critically annealed inside a muffle furnace to simulate industrial continuous annealing parameters in order to investigate the interaction between recrystallization and precipitation across transient stages of the annealing process as a function of temperature and time. The Zener pinning of precipitates and solute drag force of Mn on the recrystallization process are calculated and compared with measured values obtained from experimental studies on the recrystallization kinetics. Results suggest that the recrystallization kinetics is fastest in the base grade. For the Ti + grade, fine (<15 nm) (Ti,V)(C/N) particles retard the recrystallization kinetics. For the Ti+ and Ti + Mn + grades, solute drag effect of Mn solute atoms for dwell time longer than 2 min at annealing temperature of 800 °C is negligible.

Effect of electropulsing on microstructure and hardness of cold-rolled low carbon steel

The application of electropulsing treatment (EPT) is studied on the microstructure and hardness of cold-rolled low carbon steel. The effects of electrical pulses on the grain refinement, precipitate size evolution and hardness are investigated. It is found that applying electrical pulse decreases the grain and precipitate size and increases the hardness in the early stages of electropulsing, but the grain and precipitate size is increased and the hardness is decreased by continuing electropulsing. Also, the effect of electropulsing treatment variables as well as treated time and number of periods are discussed. It is demonstrated that increasing treated time can accelerate achieving maximum hardness in lower number of periods.

Exploring the microstructure and tensile properties of cold-rolled low and medium carbon steels after ultrafast heating and quenching

The aim of the present study is to evaluate the impact of heating rate on the microstructure and tensile properties of cold-rolled low and medium carbon steels. For this purpose, cold-rolled low and medium carbon steels were subjected to short peak-annealing experiments at 900 and 1100 °C under three heating rates (10, 450 and 1500 °C/s). The microstructure reveals a mixture of phases and microconstituents (ferrite, bainite, and as-quenched martensite) which are related to the carbon heterogeneities in austenite. The microstructural characterization suggests that the grain refinement achieved after ultrafast heating has a minor effect on the yield and ultimate tensile strength, compared to the relative microstructural distribution. It is suggested that the interplay of various strengthening mechanisms in samples subjected to ultrafast heating rates are responsible for the observed increase in strength and ductility.

Quasi in-situ analysis of geometrically necessary dislocation density in α-fibre and γ-fibre during static recrystallization in cold-rolled low-carbon Ti-V bearing microalloyed steel

In the present study, cold-rolled low-carbon steel is annealed at three different conditions: 700 °C for 0 s, 800 °C for 0 s and 800 °C for 2 min at the heating rate of ~10 °C/s. Recrystallization behaviour on sample surface is studied using a heated stage Scanning Electron Microscopy and Electron Backscattered Diffraction. For the lower annealing temperature of 700 °C with no dwell, almost no recrystallization is observed and microstructure resembles the as-received deformed material with the exception of occasional sub-micron sized nuclei. For the annealing conditions of 800 °C 0 s and 800 °C 2 min, onset and evolution of recrystallization is observed in-situ as a function of the initial as-cold rolled texture. Slower recovery rate of alpha fibre than gamma fibre is observed and confirmed by lower drop in average geometrically necessary dislocation (GND) density for un-recrystallized alpha fibres (1.1E+14 m−2 for 700 °C 0 s, 1.4E+14 m−2 for 800 °C 0 s and 4.5E+14 m−2 for 800 °C 2 min) than for un-recrystallized gamma fibre grains (3.0E+14 m−2 for 700 °C 0 s, 6.2E+14 m−2 for 800 °C 0 s and 9.8E+14 m−2 for 800 °C 2 min) during annealing. Strong gamma texture in recrystallized matrix is found for annealing conditions of 800 °C 0 s and 800 °C 2 min. From TEM characterisation it was shown that sub-grain boundaries are decorated with fine precipitates (diameter d < 15 nm) of titanium‑vanadium carbides (Ti,V)C for the annealing condition of 700 °C 0 s, which suggests that these precipitates play a major overall role in retardation of the recrystallization kinetics.

Texture simulation of a severely cold rolled low carbon steel using polycrystal modeling

Characteristic textures of cold-rolled low carbon steel consist of the RD//〈110〉 fiber (α fiber) and ND//⟨111⟩ fiber (γ fiber). Although the development of the γ fiber has been successfully modeled by the relaxed constraints polycrystal plasticity model, modeling of the α fiber has been less successful. In this work, we investigate mechanisms underlying the development of a strong α fiber in a low carbon steel during cold rolling to large thickness reductions of 90%, 98%, and 99.8%. We compare the deformation textures measured using X-ray and electron backscatter diffraction methods with those simulated using polycrystal models, employing one of four homogenization schemes: the Taylor model, Secant model, Tangent model and an intermediate stiffness model between the Secant and Tangent models. The measured textures consist of an extremely strong α fiber and unusually weak γ fiber. The calculated textures achieve the best agreement with the measured ones when (1) the intermediate stiffness model is used to account for grain shape effects, (2) the flow rule exponent (n) is chosen to allow for multiple slip in grains, (3) latent hardening effects are suppressed, (4) ⟨111⟩ slip on {110}, {112} and {123} planes is made available for deformation, and (5) the grains shape is permitted to evolve individually. Taken together, these aspects represent indirectly the effects of cross slip on slip activity, suggesting that the strong α fiber in severely cold rolled steel results from cross slip. Although the cross slip is a well accepted mechanism in b.c.c. crystals, its connection to α fiber dominance in texture development during severe rolling deformation has not been established before.

Corrosion Inhibition of Cold-rolled Low Carbon Steel with Pulse Fiber Laser Ablation in Water

This study aims at the use of a fiber laser for modifying the surface properties of cold-rolled low carbon steel via a pulse laser ablation technique in water. The effect on the corrosion behavior of the fiber laser-treated metal surface was investigated in NaCl and HCl environments. Electrochemical tests showed significant improvement in the corrosion resistance of the laser-treated sample in NaCl, with an increase in open-circuit potential (OCP) from − 0.65 to − 0.60 V and an inhibition efficiency of 89.22% as obtained from the impedance study. Such improvement was less significant in an acidic environment. Lower corrosion rates of 20.9 mpy and 5.819 × 103 mpy were obtained for the laser-treated samples in neutral and acidic electrolytes, respectively, than the corrosion rates obtained for the as-received samples (33.2 mpy and 11.98 × 103 mpy). Morphological analysis indicated a passive film built by spherical grains of regular size on the metal surface after laser treatment. The corrosion inhibition effects in NaCl were evident by the nonexistence of the common corrosion products of lepidocrocite and crystalline structures that were seen on as-received samples; only polyhedral crystals with micrograins grown on them were seen covering the laser-treated surface. Therefore, the laser treatment using a fiber laser source improved the corrosion resistance of cold-rolled low carbon steel.