Corrosion Resistance Of Steel Research Articles

Effects of Cu Content on Inclusions and Pitting Corrosion in S32205 Duplex Stainless Steel

Cu is an austenite‐forming element in duplex stainless steel, and the precipitation of Cu‐rich phase can improve the strength of the alloy. However, the role of Cu element in the corrosion resistance of stainless steel is widely controversial. Herein, the effects of different Cu content on the formation of inclusions and the pitting resistance of duplex stainless steel are studied by using potentiodynamic anodic polarization test, immersion corrosion, scanning electron microscope, and electron probe microanalysis. The results show that the pitting potential decreases significantly with the increase of Cu content, which greatly reduces its ability to resist Cl− corrosion. The reason is that Cu increases the driving force for the formation of Al‐containing oxides, which increases the number and size of Al‐containing inclusions formed in the process of melting and solidification. At the same time, Cu promotes the formation of Cr‐depleted zone, which promotes the formation of microcracks and pitting corrosion between steel matrix and inclusions in duplex stainless steel.

AISI 440B martenzitik paslanmaz çeliğinin aşınma ve korozyon dayanımına östenitleme sıcaklığının etkisinin incelenmesi

Martenzitik paslanmaz çelikler iyi mekanik özellikleri ve orta derecede korozyon dayanımları ile diğer paslanmaz çeliklerden ayrılmaktadırlar. Belirli uygulamalarda üstün özelliklere duyulan ihtiyaç, bu çeliklerin performansının iyileştirilmesi konusunda geniş araştırmalara yol açmıştır. Bunun için ısıl işlem parametrelerinin doğru belirlenmesi önerilmektedir. Bu çalışmada AISI 440B martenzitik paslanmaz çeliğin östenitleme sıcaklığının aşınma ve korozyon dayanımına önemli ölçüde etkilediğini ortaya konmuştur. Östenitleme sıcaklığı arttıkça Cr23C6 karbürleri çözünmekte ve östenit matriste C ve Cr zenginleşmesi meydana gelmektedir. Cr zenginleşmesi korozyon dayanımını iyileştirirken, C zenginleşmesi malzeme sertliğini artırmaktadır. Ancak yüksek östenitleme sıcaklıklarında, Mf ‘in düşmesi sebebiyle kalıntı östenit miktarı artmaktadır. Aynı zamanda östenit tane irileşmesi de meydana geldiğinden, sertlikte önemli derecede azalma meydana gelmektedir. Öte yandan yüksek karbon içeriği sebebiyle martenzit fazın kristal kafesinde çarpılmalar meydana gelmekte olup, bu da koruyucu oksit filmin kararlılığını olumsuz etkileyerek korozyon dayanımını düşürmektedir. Bu çalışmada, en iyi aşınma ve korozyon dayanımı elde etmek için en uygun östenitleme sıcaklığı 1080°C olarak tespit edilmiştir.

Microstructure evolution of lean duplex stainless steel produced by a short process

A short process of direct cold rolling of continuous casting billets following solution treatment is proposed, and the effect of cold-rolled reduction on the microstructure evolution and corrosion resistance of lean duplex stainless steel (LDSS) 2101 is investigated. The results show that when the cold-rolled reduction increased to 50%, the strain-induced martensite (SIM) engulfed the austenite along the annealing twin boundaries (TBs). Furthermore, the galvanic corrosion of the martensite and matrix combined with the decreasing fraction of the low-Σ CSL boundaries results in a significant reduction in corrosion resistance at 50% cold-rolled reduction. Additionally, the majority of metastable pits were generated within the ferrite grains and at the α/γ phase boundaries.

Construction novel polybenzoxazine coatings exhibiting corrosion protection of mild steel at different concentrations in a seawater solution

In this work, a new and effective polymeric coating is used to improve mild steel's corrosion resistance. The coating incorporates a Schiff base moiety into a benzoxazine (BZ) precursor, resulting in improved protection against corrosion. The SF-Tol-BZ polymerization behavior and thermal properties were studied using differential scanning calorimetry (DSC) and thermalgravimetric analysis (TGA), respectively, at different curing temperatures. The poly(SF-Tol-BZ) cured at 240 °C had a Td10 value of 604 °C and a Tg of 225 °C. The efficacy of poly(SF-Tol-BZ) coatings in protecting mild steel (MS) from corrosion in a NaCl (3.5%) solution at room temperature was evaluated using various corrosion measurements, including open circuit potential (OCP), and electrochemical impedance spectroscopy (EIS). The results showed that increasing the poly(SF-Tol-BZ) concentration led to a corresponding increase in its protective efficiency, reaching a maximum of 92% at a concentration of 300 g/L. The coatings also exhibited a 24-fold increase in Rct values and a one-order-of-magnitude reduction in CPE compared to the bare mild steel. Finally, the poly(SF-Tol-BZ) precursors demonstrated a CO2 uptake of 23 mg g−1 (measured at 298 K).

Strength and Relaxation and Corrosion Resistance of Ultrafine-Grained Austenitic 08Kh18N10T Steel Produced by ECAP: I. Microstructure and Strength

Strength and Relaxation and Corrosion Resistance of Ultrafine-Grained Austenitic 08Kh18N10T Steel Produced by ECAP: I. Microstructure and Strength

Corrosion and abrasion behavior of high-temperature carburized 20MnCr5 gear steel with Nb and B microalloying

This paper investigates the effect of Nb and B microalloying on the wear and corrosion resistance of 20MnCr5 steel after high-temperature carburization at 950 °C. The abrasion and corrosion performance of the steel was compared using electrochemical experiments and dry sliding wear tests. The results show that Nb microalloying reduces the size of residual austenite, thereby improving the wear resistance of 20MnCr5 steel. Furthermore, the combination of Nb and B microalloying reduces the amount of residual austenite, leading to further improvements in wear resistance. Both microalloying methods reduce the wear scar depth and debris accumulation. The corrosion potentials of 20MnCr5, 20MnCr5Nb, and 20MnCr5NbB are 0.645 V, 0.627 V, and 0.675 V, respectively. The addition of Nb to 20MnCr5 steel results in higher corrosion resistance after carburization due to the refinement of needle-like martensite. However, 20MnCr5NbB steel exhibits low corrosion resistance due to the coarsening of needle-like martensite caused by B microalloying. In summary, this study provides new insights into the effects of microalloying elements on the properties of steel. The findings contribute to a deeper understanding of how to design and manufacture gears and other components with superior wear and corrosion resistance.

Use of Chromium-Manganese Corrosion-Resistant Steel in District Heating Network Applications

Use of Chromium-Manganese Corrosion-Resistant Steel in District Heating Network Applications

Enhancing corrosion resistance of additive manufactured heterogeneous martensite stainless steel by hot isostatic pressing

The effect of hot isostatic pressing (HIP) on microstructure, corrosion resistance and passive film characteristics for heterogeneous martensite stainless steel (MSS) manufactured by laser powder bed fusion (LPBF) was studied. The microstructure was mainly typical original austenite grains and martensite laths and the high content of austenite disappeared after HIP. The average grain size (about 14.09 μm) was larger than that of sample before HIP (about 4.33 μm). When the laser power was 170 W and the scanning speed was 550 mm·s−1, the density of the samples after HIP increased to >99.99%. When the scanning speed increased to 1250 mm·s−1, the density of samples increased from 97.82% to 99.89%. After HIP treatment, the passivation trend of low density (97.8%) samples was more obvious and the pitting potential increased from −44 mVSCE to 179 mVSCE. The pitting potential of high density (99.77%) samples increased from 265 mVSCE to 291 mVSCE and the electrochemical impedance value increased. The sensitivity of the samples to chloride ions significantly decreases after HIP. The donor density for sample before HIP was 2.5546 × 1020 cm−3, which was higher than that of sample after HIP (2.001 × 1020 cm−3). Therefore, the corrosion resistance of LPBF high strength stainless steel was enhanced after HIP.

Effect of Heat Treatment on Corrosion and Mechanical Properties of M789 Alloy Fabricated Using DED

The directed energy deposition (DED) process offers potential advantages, such as a large building space, limited dilutions, narrow heat-affected zones (HAZ) and potentially improved surface properties. Moreover, heat treatments have been reported to significantly improve the properties of the as-built sample by modifying the microstructure. In this study, the influences of various combinations of heating and cryogenic treatments on the mechanical performance and corrosion resistance of DED M789 steel have been critically investigated. The microstructure and hardness were examined to discuss the characteristics of the M789 parts in the as-printed and heat-treated states. The corrosion rate was determined from the weight loss monitoring based on the seawater immersion condition. The microstructural results revealed the distortion of martensite lattice and the formation of nano-carbide precipitates after the cryogenic treatment. Moreover, the microhardness of the cryogenically treated M789 steel was found to be significantly higher which was attributed to the precipitate strengthening and elimination of retained austenite, resulting from the increased volume fraction of carbides due to cryogenic treatment. The corrosion characteristics were also modified by the heating/cryogenic treatments, and the substrate-to-deposit ratio of the corrosion sample also substantially affected the overall corrosion rate.

Effects of Cu on the corrosion resistance of heat-treated weathering steel in a marine environment

The effects of Cu element on the microstructure evolution and the corrosion resistance of the heat-treated NiMo weathering steel were systematically investigated, with revealing the corresponding atomic mechanism in this work. Cu-rich precipitates (ε-Cu) with face-center cubic structure were detected in the steel after austenitizing at 1200 °C for 2 h and continuously cooling in air. ε-Cu increased the corrosion sensitivity of steel attributing to its semi-coherent feature with matrix, and further decreased the rust layer protectiveness owing to its low participation degree in the CuFeO2 formation process during long-term corrosion tests. Cu dissolved in matrix after the austenitizing and the continuous cooling in water increased the corrosion potential of steel and the CuFeO2 content in rust layer, ignoring the adverse impacts on matrix caused by the micro lattice strain of Cu atoms.

Influence of Multi-Pass Welding on the Microstructure Evolution and Corrosion Resistance of a Super Duplex Stainless Steel

Influence of Multi-Pass Welding on the Microstructure Evolution and Corrosion Resistance of a Super Duplex Stainless Steel

Benefit of the rust layer formed on AlMn lightweight weathering steel in industrial atmosphere

The rust layer of AlMn lightweight weathering steel in industrial atmosphere was investigated through rust layer analysis (structure, phase composition and elemental distribution) and electrochemical measurement. The rust layer of lightweight weathering steel exhibits superiority in terms of structure, phase composition and distribution, and electrochemical properties. The enrichment of FeAl2O4 in the inner rust layer refine the rust grain, promotes the transformation of γ-FeOOH to α-FeOOH, increases the compactness of the rust layer, and produces an electronegative inner rust layer to block the S element. Mn changes the content of FeAl2O4 and α-FeOOH in the form of MnO/MnO2, which affects the corrosion resistance of lightweight weathering steel.

R4 Kalite Açık Deniz Demirleme Zinciri Çeliğine Uygulanan Bor-Alüminid Kaplamanın Çukurlaşma ve Tribo-Korozyon Davranışına Etkisi

Offshore mooring systems are susceptible to wear, corrosion, and fatigue damage, making improving their tribocorrosion resistance essential. This study aims to evaluate the effects of boron-aluminizing treatment on the corrosion and tribocorrosion resistance of R4 steel in a marine environment. The boron-aluminide coating was characterized by SEM, EDS, and XRD, revealing the presence of FeAl as the dominant phase with minor amounts of FeB, Fe2B, and Fe2Al5 phases. Results showed that the boron-aluminide coating improved the corrosion resistance of R4 steel, acting as a barrier between the coating and the steel substrate and maintaining its corrosion resistance even under wear conditions. The findings suggest that the boron-aluminide coating can potentially improve the corrosion and tribocorrosion resistance of R4 steel in marine environments, making it a cost-effective alternative to passive materials for the thermochemical coating of low-alloy steels.

Electrochemical studies on the corrosion resistance of mild steel in 1 M HCl solution before and after emulsion coating

Electrochemical studies on the corrosion resistance of mild steel in 1 M HCl solution before and after emulsion coating

Electrochemical investigation of the influence of a durable exterior emulsion coating on the corrosion resistance of mild steel in simulated concrete pore solution

Electrochemical investigation of the influence of a durable exterior emulsion coating on the corrosion resistance of mild steel in simulated concrete pore solution

Preparation and properties of Al/Si coating with excellent formability and corrosion resistance on steel plate

In order to simultaneously improve formability of the coated steel and corrosion resistance of steel, Al/Si coating with tailored Si content, controllable composition and structure were prepared on Q235 by combining magnetron sputtering and then treated by heat treatment. The effect of Si content on the thickness, composition, structure of Al/Si coating on the surface of Q235 steel, and corrosion resistance and formability of Al/Si coated Q235 steel were systematically investigated. With 160 W of Al target power and different Si target power (0, 60, 80 and 100 W), the thickness of the coating on Q235 steel for 1.5 h is about 5 µm. Al/Si coating thickness with 80 W of Si target power is 5.33 ± 0.32 µm. The coating on Al/Si80-Q235 is uniform and dense, and mainly consists of FeAl2Si, Fe3Al, Fe2Al5, and Al2O3. Al/Si80-Q235 demonstrated excellent formability and Al/Si80 coating improved corrosion resistance of Q235 steel. When immersed in NaCl solution, the self corrosion current density of Al/Si coated Q235 was significantly lower than Al coated Q235. Especially, the self corrosion current density of Al/Si80-Q235 was only 1/51 that of Al coated Q235. The corrosion resistance of Al/Si coated steel was remarkably improved compared with Al coated steel due to the addition of Si.

Selective laser melting of 316L–CuCrZr bimetallic structure via IN718 transition layer

Steel/copper bimetallic structural materials combine the good strength and corrosion resistance of steel with the high thermal and wear resistance of copper and have been widely used in fusion reactors, conformal cooling channels, and heat transfer devices. Due to the large difference in thermal and physical properties of steel and copper, and the immiscibility of steel and copper, the bonding interface usually produces a large residual stress during the forming process, which leads to the formation of interface cracks. In order to combine CuCrZr with 316L stainless steel by using selective laser melting technology, IN718 was deposited on 316L stainless steel as a transition layer. The effects of the IN718 alloy transition layer on the microstructure, phase composition, and mechanical properties of the interface of 316L–CuCrZr were studied. IN718–316L had no defects such as pores and cracks at the interface and achieved good metallurgical bonding. The IN718–CuCrZr interface area and copper side had round key holes and relatively small pores. In the solidification process, IN718 preferentially solidified in the shape of fine particles, providing a nucleation point for the copper grain, thus forming equiaxed grains because of the high cooling rate of the interface. No macroscopic defects were observed at the bonding position of the 316L–IN718–CuCrZr samples, and the elements at the interface were fully diffused by each other. The tensile strength of the 316L–IN718–CuCrZr samples reached 403 MPa, and the interface strength was significantly improved upon the addition of the transition layer.

Enhancing corrosion resistance of carbon steel and stainless steel through pothocathodic protection using TiO2-polyvinyl butyral electrophoretic deposition coating

Photocathodic protection (PCP) is a promising eco-friend method to reduce the corrosion of metals. Considering industrial applicability, it is imperative to adopt cost-effective materials for implementing PCP on corrosion-vulnerable carbon steel (CS). This study examined the potential of photocatalytic TiO2-polyvinyl butyral (PVB) materials for PCP of CS and stainless steel (STS) using commercially available P-25 photocatalyst particles. The TiO2-PVB-electrophoretic deposition (EPD) film exhibited the improved cathodic protection time of STS owing to PVB addition. When the film was applied to various substrates, it achieved a PCP of −0.6 to −0.7 VSCE due to the photogenerated electrons under UV irradiation. For the CS, the PCP potential was maintained for more than 1.5 hours, even after light irradiation. We have found that PCP was achieved by Ecorr > EPCP of CS in an acidic environment, while in a neutral and basic environment, the corrosion of CS and photocathodic electronation contributed simultaneously to Ecorr ≈ EPCP. One findings is that the application of PCP effectively reduces the corrosion rate of CS in a 3.5% NaCl solution, regardless of the pH of the corrosive environment. This highlights the capability of PCP as a viable method for mitigating corrosion on CS.

Effect of Ti addition on mechanical properties and corrosion resistance of X80 pipeline steel

In this study, the effects of Ti addition on the mechanical properties and corrosion resistance of X80 pipeline steel were investigated using tensile impact, electrochemical and neutral salt spray tests, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results show that the addition of Ti can promote the formation of acicular ferrite (AF), resulting in significant grain refinement. It can improve the tensile strength, yield strength and impact toughness of X80 pipeline steel, with the highest value of tensile strength at 0.04 wt % Ti content, which is 8% higher than the original; yield strength is 18% higher; and impact work is 9% higher. The best corrosion resistance of the pipeline steel is achieved at a Ti addition of 0.04 wt %, with a reduced corrosion weight loss rate, 28% less than the original. The Tafel curve is shifted forward, the self-corrosion potential Ecorr increases and the corrosion current density Icorr decreases, improving by 10% from the original. The capacitive arc radius and Rct increase, the resistance to corrosion reaction increases. The corrosion products are mainly loose and porous γ-FeOOH and β-FeOOH in the early stage of corrosion, and more α-FeOOH and Fe3O4 are generated in the later stage.

Effects of Ce-La rare earth microalloying on the microstructure and corrosion characteristics of Q420 high-strength steel

In the present study, the effects of rare earth alloys on the corrosion resistance of Q420 high-strength steel have been studied by performing the neutral salt spray test and the electrochemical test. The influence rules for rare earth microalloying on the improvement of the corrosion resistance of Q420 high-strength steel, were then clarified. The results showed that the addition of rare earth elements will improve the corrosion resistance of Q420 steel. The corrosion resistance of the 2# and 3# steel was found to be better than that of the 1# and 4# steel. This was related to the effect of rare earth alloys on the shape and size of the inclusion. With a further increase in the content of rare earth elements,a large-sized inclusion appeared in the steel. When the content of the rare earth element was 0.01 %, the number and size of the inclusions in the Q420 steel were the smallest, and the corrosion resistance of the Q420 steel was the best. The corrosion resistance of the high-strength steel for transmission towers can thus be effectively enhanced by controlling the amount of rare earth element addition.