Corrosion Resistance Of Steel Research Articles

Evaluation of corrosion resistance of 316L stainless steel by laser ultrasonic nondestructive testing technology

At present, the corrosion resistance of materials such as 316L stainless steel is mainly tested by electrochemical testing, which is time-consuming, laborious and environmentally unfriendly. In this paper, the laser ultrasonic detection technology, which is a rapid, non-destructive, pollution-free microstructure and corrosion resistance evaluation method is used for the detection of 316L stainless steel, and the ultrasonic signals are filtered by the wavelet threshold denoising method. The results show that the laser ultrasonic attenuation coefficient obtained by the wavelet threshold denoising signal processing method has a good correlation with the corrosion resistance of 316L stainless steel. A laser ultrasonic potential evaluation model was established based on the passivation film rupture potential and ultrasonic attenuation coefficient. The average relative error of the evaluation model for corrosion resistance of 316L stainless steel is less than 5.00%. The relative error of corrosion resistance evaluated by the laser-receiving method is lower than that by the probe-receiving method. It is feasible to nondestructive evaluation of the corrosion resistance of 316L stainless steel by laser ultrasonic technology.

Strength and Relaxation and Corrosion Resistance of Ultrafine-Grained Austenitic 08Kh18N10T Steel Produced by ECAP: II. Relaxation Properties and Intergranular Corrosion Resistance

Strength and Relaxation and Corrosion Resistance of Ultrafine-Grained Austenitic 08Kh18N10T Steel Produced by ECAP: II. Relaxation Properties and Intergranular Corrosion Resistance

Review—Understanding and Controlling the Electrochemical Properties of Sulfide Inclusions for Improving the Pitting Corrosion Resistance of Stainless Steels

Review—Understanding and Controlling the Electrochemical Properties of Sulfide Inclusions for Improving the Pitting Corrosion Resistance of Stainless Steels

Web Bearing Test of Cold‐Formed Austenitic Stainless‐Steel Channels Under Interior Loading

AbstractDuctility, durability and high corrosion resistance of stainless steels make them appealing to use in construction industry. When used as structural sections, they are, however, subjected to localised failure in the web. This study aims to examine the structural behaviour of cold‐formed austenitic stainless steel channels under localised interior bearing loads. The results of 21 tests on unlipped channels with different cross section sizes and thicknesses are presented. Nonlinear quasi‐static Finite Element (FE) model is then developed. The FE model is validated against experimental test results and demonstrated good agreement in terms of bearing strength and failure modes. In addition, the experimental and FE results are used to compare the results against the results predicted in accordance with the American specification SEI/ASCE 8:2002 and European Standard EN 1993‐1‐4:2006. It is found that the current design equations are unreliable and too unconservative to use for cold‐formed austenitic stainless steel unlipped channels, especially when compared to SEI/ASCE 8:2002, as much as 41%.

Enhancing corrosion resistance of bridge structural steel through graphene/cerium hydroxide composite coatings in polluted marine atmospheres

Enhancing corrosion resistance of bridge structural steel through graphene/cerium hydroxide composite coatings in polluted marine atmospheres

The dual nature of Cu content on the corrosion resistance of low alloy steels in sulfuric acid: A time-dependent reversal of corrosion resistance

The corrosion performance of low alloy steels with varying Cu contents (ranging from 0 to 1.2 wt%) was evaluated in a 10 wt% H2SO4 solution at room temperature. By incorporating Cu, the active dissolution of the bare steel is effectively suppressed, leading to enhance corrosion resistance as the Cu content increases. However, during immersion, the corrosion product film transitions from CuO and Cu(OH)2 dominance to Cu2O and Cu0 dominance. Simultaneously, hydrogen reduction induces cracks in the film, causing an uneven Cu distribution and gradual corrosion resistance degradation with higher Cu content and longer immersion duration.

Structure and Protectiveness of Rust Layers Grown on Low-Alloyed Steels Under Cyclic Wet/Dry Corrosion Tests

Carbon steels are widely used in various infrastructures due to their superior mechanical properties in addition to low cost, but the mechanical properties can be deteriorated when steels are corroded. It is well-known that the weathering steels where small amounts of alloying elements such as Cu, Cr, Ni, Si and Mn are included form compact protective rust layers during the long-term exposure to atmospheric environment, resulting in superior corrosion resistance. However, as some of the alloying elements such as P that are effective to improve the atmospheric corrosion resistance of carbon steel cause segregation in the solidification process during welding, the amounts of such alloying elements have been strictly limited. The segregation of additive elements can be suppressed in stir friction welding, so-called FSW, in which metallic materials are joined in a solid state, leading to the assumption that the restrictions on the types and amounts of alloying elements can be reduced when FSW is applied instead of conventional welding. In the present work, the structure and corrosion resistance of rust layers formed on various low-alloyed steels designed for FWS are evaluated. Ingots of various low-alloyed steels including Al and P, both of which have been proved to be effective to improve the atmospheric corrosion resistance of carbon steel, were prepared using a high-frequency vacuum induction furnace. The ingots were hot-rolled at 1273 K into a plate with the thickness of approximately 2 mm and then cut into specimens with the dimension of 20 mm × 30 mm. All specimens were subjected to a laboratory cyclic corrosion test according to SAE J2334 which simulates a severe coastal atmosphere environment. In the SAE J2334 test, the specimens were kept for 6 h in a tightly sealed box where the temperature and relative humidity (R. H.) were controlled at 323 K and 100%, respectively (humid stage). Then the specimens were immersed in an aqueous solution containing 0.5 mass% NaCl, 0.1 mass% CaCl2 and 0.075 mass% NaHCO3 for 15 min. (immersion stage), followed by holding for 17h 45 min. in the sealed box at 333 K and 50%R. H. (dry stage). These three stages were repeated up to 30 cycles. After the cyclic corrosion test, rust layers on the specimens were characterized with X-ray diffraction and elemental distributions in the rust layers were evaluated with energy-dispersive spectroscopy. The corrosion current density was estimated from extrapolating Tafel slopes in polarization curves measured for the specimens subjected to the cyclic corrosion test. In XRD measurements for the specimens after 30 cycles of the cyclic corrosion test, peaks derived from α-FeOOH, β-FeOOH, γ-FeOOH and Fe3O4 were found. The fraction of the components in rust layers grown on the specimens was estimated, providing the fractions: 30-50% of α-FeOOH, 20-40% of β-FeOOH, 4% of γ-FeOOH and 30-50% of Fe3O4. Among the components, the fraction of α-FeOOH which is well-known as protective rust increased with increasing the addition of Al and P in specimen. Furthermore, it was found from EDS analysis on the cross-sections of the specimens that Al and P were distributed in the rust layers formed on the specimens in which Al and/or P were included. This indicates that Al and P can be related to the imcreased fraction of α-FeOOH in rust layers. The corrosion current density decreased with increasing the amounts of Al and P in the specimens, implying that Al and P improved the protectiveness of rust layers, that is, the increased corrosion resistance of low-alloyed steels. Similar trend was found in the corrosion rate estimated by the weight-loss method. These beneficial effects of Al and P are attributed to the increased fraction of protective α-FeOOH in rust layers.

Study on the corrosion inhibition performance of composite inhibitor on carbon steel in stone processing wastewater

AbstractThe circular saw blade, which is mainly composed of carbon steel, is used to cut the stone. However, the carbon steel is easily corroded in stone processing wastewater, shortening its lifespan. In this study, a new composite inhibitor of sodium nitrite, sodium molybdate, sodium silicate, sodium tungstate, and sodium citrate was investigated firstly, and then, its inhibition efficiency for carbon steel in stone processing wastewater was explored using electrochemical measurements and weight loss measurements. The results showed that the composite inhibitor as a mixed‐type inhibitor displayed good inhibitory performance. Surface analysis including scanning electron microscope, atomic force microscope, X‐ray photoelectron spectroscopy analysis, and contact angle test further revealed the form of protection of the steel surface by composite corrosion inhibitors. The prepared composite inhibitor exhibited excellent corrosion resistance for carbon steel in stone processing wastewater, and it is believed that the composite inhibitor has certain application potential in industries.

The dual pretreatment of phytate-molybdate for corrosion resistance of carbon steel in simulated concrete pore solution

In this study, phytic acid conversion film and molybdate corrosion inhibitor were combined using the dual pretreatment method. The main purpose was to make up for the deterioration of corrosion resistance caused by the cracking of the phytic acid conversion film. Electrochemical analysis showed the corrosion resistance of the dual pretreatment was increased by 99.0% and 102.3% respectively compared with the single phytic acid and molybdate pretreatment. In addition, the rapid corrosion initiation time was 96 h and 108 h later than that of single phytic acid and molybdate pretreatment, respectively. The corrosion protection mechanism of dual pretreatment was investigated by means of morphology and composition analysis. Phytic acid and iron substrate were combined by chelating, and molybdate corrosion inhibitor reacts with iron substrate to form Fe2(MoO4)3/FeMoO4 through phytic acid film cracks to form corrosion protection, which showed excellent synergistic effect. On the one hand, the dual pretreatment makes up for the shortcomings caused by cracks in the phytic acid conversion film itself, and on the other hand, it also reduces the amount of corrosion inhibitor by using the pretreatment method, and effectively avoiding the problems of difficult migration and easy leakage of corrosion inhibitor.

Investigation of rust layer on low alloy steel with 0.40 wt% Sn in a rural atmospheric environment

This study investigates the formation and properties of rust layers on low alloy steel containing 0.40 wt% tin (Sn) in rural atmospheric environments. The rust layer was analyzed using various techniques, including scanning electron microscopy, X-ray diffraction and Raman spectroscopy. Additionally, a new corrosion big data sensor was used to evaluate the corrosion resistance of Sn-containing low alloy steels. Results show that the presence of Sn in the low alloy steel positively affects corrosion resistance, resulting in the formation of a denser and more protective rust layer. The corrosion big data technology is a precise and intuitive approach for identifying the subtle impact of Sn on the corrosion resistance of low alloys. These findings offer insights into the mechanisms behind the corrosion resistance of low alloy steels in rural atmospheric environments and highlight the potential of Sn as an effective alloying element for improving the corrosion resistance of such structural materials.

Web bearing design of cold-formed austenitic stainless steel un-lipped channels under localised interior loading

The high corrosion resistance, recyclability, ductility, and durability of stainless steels make them appealing for use in the construction industry. However, when used as structural channel sections, they are subject to localised failure in the web. This study aims to evaluate the structural behaviour of cold-formed austenitic stainless steel unlipped channels under localised interior loading. The results of conducting a novel testing programme with 21 new tests on such channels with different cross-section sizes and thicknesses are presented. Then a non-linear quasi-static Finite Element (FE) model is developed. The FE model is validated against experimental test results and found to demonstrate a good agreement in terms of bearing capacity and failure modes. It is found that no cold-formed stainless steel standard provides web bearing capacity equations for the localised interior loading (IL) that apply when simulating a floor joist on a solid foundation. The web bearing capacities are compared with capacities determined from the literature (including DSM). It is found that for the case of unlipped channels (unstiffened flanges), the current equations are unreliable and unconservative by up to 36%. The experimental investigation shows that, the American specification (SEI/ASCE 8:2002) is unconservative as much as 41%. Using both experimental and numerical results from this study, a new design equation is proposed for austenitic stainless steel unlipped channels under localised interior loading.

Oxidation behavior and corrosion properties of 2-GPa grade Co-reduced ultrahigh-strength stainless steel

This study investigated the oxidation behavior and corrosion resistance of 2-GPa grade ultrahigh-strength stainless steel. Results revealed that the addition of V to Co-reduced FerriumS53 (7Co1V) accelerated the precipitation of MC carbide during aging, while inhibiting the precipitation of Cr-rich M23C6 carbide. A significant amount of Cr was predicted in the microstructure of the alloys, and this microstructure increased the partitioning of Cr to the alloy surface and provided enhanced resistance against corrosion pitting. These findings suggest that the addition of V into Co-reduced stainless secondary hardening steels can enhance their oxidation and corrosion resistance without compromising their mechanical properties.

Effect of Thermo-Mechanical Processing on Initiation and Propagation of Stress Corrosion Cracking in 304L Austenitic Stainless Steel

Despite the high corrosion resistance of austenitic stainless steels (SSs), a significant reduction of stress corrosion cracking (SCC) resistance has been reported in cases of high residual stress and metastable microstructural features. In this study, the effect of thermo-mechanical processing (TMP) on the initiation and propagation of SCC in 304L SS was studied. To better understand the SCC mechanisms, three TMPs conditions—welded, solution annealed at 1050 °C for tens of seconds, and straightened—were used. The research focused on analyzing the initial microstructure, residual stress, and hardness along the depth direction to assess SCC resistance and establish correlations with the observed SCC modes. Experimental results demonstrated that transgranular SCC was observed in regions exhibiting elevated residual stress induced by welding and straightening processes. Furthermore, the presence of strain-induced martensite transformation and slip bands formed during plastic deformation were identified as additional factors contributing to the susceptibility of SCC. The study findings highlighted that the magnitude and distribution of residual stresses, in conjunction with microstructural evolution, could be varied depending on the specific TMP condition, leading to different SCC susceptibilities, cracking modes, and directions.

Chlorine resistance of tannic acid anticorrosive coating on galvanized steel in simulated concrete pore solution

Reinforced concrete structures are easily damaged by corrosion in a chloride environment. Although zinc coating provides a promising method for inhibiting steel corrosion, it can inevitably dissolve and fail under a chlorine-containing concrete environment. In this study, the chloride corrosion resistance of coatings prepared with different concentrations of tannic acid was studied in a simulated concrete pore solution. The surface morphology and chemical composition of the different samples were investigated. The results of the corrosion immersion and electrochemical tests showed that the prepared corrosion resistance coating effectively enhanced the chlorine corrosion resistance of steel. The 10 wt% tannic acid coating on the galvanized steel surface had good corrosion resistance. The corrosion resistance efficiency increased 77.8%. The green and environmentally friendly method is expected to provide an essential application in chloride corrosion protection of concrete structures.

Influence of grain refinement on strength and corrosion resistance of 316LN steel welded joint

The cost of repairs for corrosion damage can be decreased with corrosion prevention. All industries, including those in the oil and gas sectors, as well as the majority of human endeavors, are impacted by corrosion. Optimal corrosion management techniques may increase efficiency and cut costs when corrosion is taken into account along the entire value chain. The influence of smaller grains on sensitization microstructure, strength, and corrosion of TIG-welded 316LN SS joints was summarized in this investigation. The welded metal structure and electrochemical resistance of 316LN steel after TIG welding and appropriate heat treatment have been summarized by using Electron Back Scatter Diffraction and Tafel plot test methods. This study summarized the understanding of the effect of TIG welding and appropriate annealing on the deformed and welded structure of 316LN steel. The corrosion rate drastically increases after TIG welding (HAZ zone) of forged samples as compared to base metal (un-welded zone) samples. The mechanism behind the reduction of corrosion resistance is the Depletion of the chromium oxide film. From the results findings, the corrosion rate decreased after TIG welding of forged samples. In the corrosion plot, shifting the intensity of the corrosion current to the passive direction indicates the formation of Cr2O3 after the annealing of welded and forged samples. From the EBSD micrographs, it was observed that the appropriate annealing after welding and forging produces fewer pits as compared to the base metal. Results also indicates that both the mechanical characteristics and corrosion resistance deteriorate as a result of sensitization.

Effect of excitation vibration on mechanical property and stress corrosion resistance of cast steel

Cast steel parts can realize rapid prototyping effectively, which is suitable for complex structural design. However, due to the large residual stress, the problem of mechanical property degradation is more obvious. In order to solve this problem, a high temperature excitation vibration treatment scheme is proposed in this paper. By applying different excitation frequencies and impact forces, the effects of mechanical properties and stress corrosion properties are studied and verified. Based on the finite element software ANSYS, the modal shape and resonant frequency of the cast steel parts are obtained, and verified by the sweep frequency module in the excitation vibration system. According to the characteristics of modal shape, five typical detection paths are set, and stress sensors are arranged every 200 mm. In order to obtain the specific effects of excitation frequency and impact force amplitude on mechanical properties, nine parts samples were prepared on the same production line according to the matching requirements of test parameters. In addition, the main external parameters that remain unchanged during vibration excitation are set as initial 750 ℃ and vibration excitation time of 60 s, which can fully affect the effect of austenite transformation. Keeping the synchronization of test parameters in different samples, the distribution rules of residual stress under different excitation frequencies and forces are obtained and analyzed. In the aspect of mechanical properties, the microstructure, hardness, yield strength and tensile strength of the specimens subjected to vibration were compared and analyzed. In the aspect of stress corrosion performance research, stress corrosion cracking test was carried out in weak acid environment to obtain the tensile stress curve and fracture morphology of the specimen. The results show that the excitation vibration at high temperature can effectively eliminate the residual stress of cast steel parts, but the increase of excitation frequency does not correspond to the effect of residual stress elimination. When the exciting force exceeds a certain value, the stress relief effect cannot be further improved. Excitation vibration can reduce the internal hardness of cast steel parts to a certain extent, and improve the yield strength and tensile strength. At the same time, it has a positive role in promoting the improvement of stress corrosion resistance.

Evolution of the sigma phase and its effect on the corrosion resistance of ASTM A890 3A duplex stainless steel

The sigma (σ) phase is a detrimental precipitation that affects the performance and application of duplex stainless steel (DSS). In this study, the evolution of the σ phase and its influence on the corrosion resistance of the ASTM A890 3 A DSS were analyzed quantitatively by aging at 750 °C for 3–96 h for the first time. With increasing aging time, the amount and rate of precipitation of the σ phase significantly changed. The fraction of the σ phase increased from 0.65% to 23.51%, accompanied by a decrease in ferrite content and an increase in austenite content. During the evolution of the σ phase, a combined process of nucleation and growth controlled by the eutectoid reactions in the first 3–24 h and a growth process controlled by diffusion in the subsequent 24–96 h were observed. The deteriorated corrosion resistance after aging was closely related to the fraction and distribution morphology of the σ phase. Under a precipitation fraction of the σ phase between 0% and 0.65%, the passive current density of the DSS increased, the pitting potential decreased. The width of the passivation region between 0.65% and 19.07% of the σ phase narrowed, and instability formed. The critical aging time for the transformation from passive to active DSS was between 48 h, corresponding to a content of the σ phase of 19.07%. The passivation region almost completely disappeared. In addition, the uniformity in distribution of the σ phase also influenced the corrosion resistance.

Effect of Strain Hardening on Wear and Corrosion Resistance of 316L Austenitic Stainless Steel

Effect of Strain Hardening on Wear and Corrosion Resistance of 316L Austenitic Stainless Steel

Exploring the Impact of Cooling Rate on Microstructural Features, Mechanical Properties, and Corrosion Resistance of a Novel Nb-Stabilized Super Duplex Stainless Steel in Shielded Metal Arc Welding

The corrosion and mechanical response produced by quenching in the welded joint of a new Nb-doped stainless steel designed by the CALPHAD method and produced by open-atmosphere casting with recycled materials were investigated to contribute to the circular economy and to establish disruptive manufacturing criteria based on metallurgical principles. The steel was initially subjected to solubilization heat treatment and partial solubilization treatment at 1090 °C to obtain an appropriate α/γ balance and carbide solubilization. It was then welded by the SMAW process, quenched, and tempered at three different cooling rates. As a result, a good fit between the phases predicted by the CALPHAD method and those observed by X-ray diffraction and scanning electron microscopy were obtained, with minor differences attributable to the precipitation and diffusion kinetics required for dissolution or nucleation and growth of the phases in the system. The forced air quenching mechanism was identified as providing an α/γ phase equilibrium equivalent to 62/38 as the most effective quenching method for achieving the optimum mechanical and corrosion response, even with the post-weld σ phase and showing superior results to those of the base metal. The outstanding mechanical and corrosion responses resulted from a proper balance of the primary phases in the duplex steel with a precipitation-strengthening mechanism. The damage tolerance obtained by forced air quenching was superior to that obtained by water and air quenching, with a PSE of 24.71 GPa% post-welding.

Effects of Solid-Solution Carbon and Eutectic Carbides in AISI 316L Steel-Based Tungsten Carbide Composites on Plasma Carburizing and Nitriding

AISI 316L stainless-steel-based tungsten carbide composite layers fabricated via laser metal deposition are used for additive manufacturing. Heat treatment practices such as low-temperature plasma carburizing and nitriding improve the hardness and corrosion resistance of austenitic stainless steels via the formation of expanded austenite, known as the S phase. In the present study, practices to enhance the hardness and corrosion resistances of the stainless-steel parts in the composite layers have been investigated, including single plasma carburizing for 4 h and continuous plasma nitriding for 3.5 h following carburizing for 0.5 h at 400 and 450 °C. The as-deposited composite layers contain solid-solution carbon and eutectic carbides owing to the thermal decomposition of tungsten carbide during the laser metal deposition. The eutectic carbides inhibit carbon diffusion, whereas the original solid-solution carbon contributes to the formation of the S phase, resulting in a thick S phase layer. Both the single carburizing and continuous processes are effective in improving the Vickers surface hardness and corrosion resistance of the composite layers despite containing the solid-solution carbon and eutectic carbides.