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The compatibility problems become main concern in the utilization of biodiesel especially regarding to degradation and corrosion. The present study is conducted to describe the corrosion behaviour that occurs in steel tanks after contact with palm-based biodiesel for a period of 7 months. The storage tank used is respectively made of galvanised steel (GS), carbon steel (CS) and stainless steel (SS). It is performed in vertical cylinders with a floating-roof model. In every 30 days of storage time, the profile changes in the wall, roof and base surface of each tank were observed. The oil fuel properties were monitored in the parameter of viscosity, acid numbers, water content and oil colour. The topographic profiles on the surface of the walls and bottom of each tank wetted by biodiesel were examined over three zones inside the tanks using an endoscope imager. The main results of this study indicate that the tank steel with different protective layers exhibits different types of corrosion. The corrosion was localized in SS tanks but generalized in GS and CS tanks. The oil contamination in SS tanks was relatively lower than that in CS and GS tanks. The type of corrosion performed differently in different zones on the inside of the tank. The potential for leaks is greater at the base than on the walls and roof of the storage tank.

The role of biofilm in the Microbiologically Influenced Corrosion (MIC) of carbon steel by Sulfate Reducing Bacteria (SRB) in oil and gas exploitation, and geothermal installations is investigated. Simulated biofilm made of calcium alginate, abiotic sulfide (to mimic SRB metabolic end product H2S), CO2 (to mimic CO2 from SRB dissimilatory sulfate reduction) and simulated brine (3.0 wt% NaCl) are used to simulate the SRB environment. For reference experiments, distilled water is used instead of simulated brine. The electrochemical results show that the simulated biofilm in the reference at 120 min exposure time and in brine experiments neither inhibits nor accelerates corrosion. These results are strongly supported by corrosion kinetic adsorption parameters, statistical T-test, ICP-OES, pH, SEM-EDS and XRD. The results contradict with the existing literature on the role of biofilm and this is likely due to the presence of both H2S and CO2 as simulated SRB metabolites. Despite of this discrepancy, the obtained corrosion rates (0.25 to 1.6 mm/year) in the simulated SRB environment are comparable to published corrosion rates obtained in SRB experiments (0.20 to 1.2 mm/year). The results highlight the novelty of this research and have a direct impact on the role of other microbial metabolites on the corrosion of carbon steel.

To explore the evolution mechanism of multistage machining processes and torsional fatigue behaviour based on strain energy for the first time and provide process optimization of axis parts of low-alloy medium-carbon steel for service performance, four multistage machining processes were applied to the 45CrNiMoVA steel, including the rough turning process (RT), RT + the finish turning process (FRT), FRT+ the grinding process (GFRT) and RT+ the finish turning process on dry cutting condition (FRT0). The result showed that the FRT process’s average low-cycle torsional fatigue life increased by 50% when it evolved from the RT process. The lower surface roughness of Ra 1.3 μm caused the total strain energy to increase by 163.8 Pa mm/mm instead of the unchanged strain energy density, and the crack feature evolved from some specific bulges to flat shear plane characteristics. When the GFRT process evolved from the FRT process, its average fatigue life increased by 1.45 times, compared with the RT process. Plastic strain amplitude decreased by 21%, and the strain energy density decreased by 4% due to more considerable compressive residual stress (-249 MPa). Plastic deformation layer depth had a consistent tendency with surface roughness. In this paper, surface integrity evolutions on cyclic characteristics and fatigue behaviour have also been explained. A fatigue life prediction model based on the energy method for machined surface integrity is proposed.

We all know that heat exchanger is one of the equipment to transfer the heat between the fluids. Heat will transfer from one side of fluid to another side of fluid. In this project we use counter flow heat exchanger. In this heat exchanger one kind of fluid will come from one side and another kind of fluid will come from another side. Both fluids will be sending inside to the tube in opposite direction. Here we are using two medium one is hot fluid and another one is APISN (American Petrol Institution of Super Natural) with B grade oil. Inside of apparatus we are using copper tube, to enhance the heat transfer. Because that copper is having higher thermal conductivity (385 W/m K). When we compared to the carbon steel (19 W/m K), copper is having more thermal conductivity. The reason for choosing copper tube is not only higher thermal conductivity; it's also having properties like corrosion resistance, max allows able stress and internal pressure. Hot fluid will be send through the way of inside of the copper tube. Over the copper tube will send APISN oil, both will be send in an opposite manner. In a setup of counter flow heat exchanger, we put two holes with some dimension. When the fluid goes inside of the tube we insert the digital thermo-meter to note down the temperature of both inlet and outlet. After taking all reading we will evaluate the counter flow heat exchanger with term of efficiency.

The purpose of this research was to discover the various reasons of failures and appropriate repair options for the line ducting cleaning unit system at PT Pusri Palembang's NPK-1 production facility. The main cause of the failures was determined to be a deterioration of the ducting line material caused by corrosion on the inner side of the ducting pipe composed of SS400 carbon steel. We made investigation including an analysis of the thickness of the damaged ducting pipe, as well as a visual check. The investigation showed that the corrosion caused an average drop in pipe wall thickness of up to 70%, according to the findings. The fixed load superimposed on the ducting pipe and the carrying capacity of the piping affect ducting strength, but corrosion on the inner surface of the pipe, caused by direct contact with corrosive and hygroscopic process dust, reduces ducting wall strength against axial and lateral loads. Failure of this ducting pipe caused losses and unscheduled shutdowns of production process, and increased the repair costs also could increase the risk of human accidents. The suggestion as this investigation results is to upgrade the ducting pipe materials to the more corrosion-resistant materials, such as stainless-steel grade SS304. Other suggestion should be taken is also regularly to inspect the ducting cleanness for the internal of ducting and control the dust flow rate through the scrubbing system. As conclusion, the suggestions given are to mitigate the risk of corrosion impact by maintaini­­­­­­ng ducting strength within the minimizing ducting system failures and ensuring the NPK plant's operation reliability.

In order to replace hazardous molten lead baths in the heat treatment of carbon steel wire with environmentally friendly fluidized bed furnaces a better understanding is needed of their heat transfer rates. There has been considerable work done in examining heat transfer rates to large cylinders immersed in fluidized beds, and some on wire sized ones as well, but all previous studies have been conducted on static cylinders. In order to gain a deeper understanding of heat transfer rates to a moving wire immersed in a fluidized bed furnace an apparatus has been constructed to move a wire through a fluidized bed. The heat transfer rates were calculated using the difference in inlet and outlet temperatures, wire speed and the bed temperature. As predicted, correlations for static wire were found to under-predict heat transfer rates at higher wire speeds, so a new correlation was developed by modifying an existing one.

Ni/Co/SiO2 hydrophobic coatings were fabricated by embedding SiO2 nanoparticles into Ni/Co coatings using pulsed electrodeposition, followed by a liquid-phase hydrophobic treatment. Microstructure and morphology analysis of the composite coatings revealed that the SiO2 nanoparticles were homogenously distributed in the Ni/Co coating, and the surfaces of the samples were close-grained without crack. Furthermore, the SiO2 nanoparticles in the coating formed micro-nano structures on its surface, such that the contact angle reached 125° following the hydrophobic modification. The surface of the hydrophobic coating was found to be abrasion resistant and exhibited long-term stability in water. The corrosion inhibition efficiency of the Ni/Co/SiO2 hydrophobic coatings on a Q235 carbon steel substrate in simulated seawater solution reached 98.6%, indicating optimal anti-corrosion performance.

In this research work, samples of low carbon steel AISI 1017 subjected to shot peening process for 15 minutes. These samples were cleaned and coated with epoxy. The coating process were carried out with epoxy, epoxy mixed with alumina powder, epoxy mixed with silicon carbide powder and the last case, the steel coated with epoxy mixed with alumina and silicon carbide powders. Results showed that the corrosion resistance of steel coated with epoxy and alumina were better as compared with other samples .

Background: Curcumin-stabilized silver nanoparticles (Cur-AgNp) synthesized by a facile chemical method. The synthesized AgNp was, for the first time, used as a bio-derived corrosion inhibitor for carbon steel in the 1M sulphamic acid medium. Methods: The electrochemical studies via impedance spectroscopy, potentiodynamic polarization, and surface analysis are reported in the communication. The maximum inhibition efficiency of 92.87% obtained at 800 mgL-1 . Results: The impedance measurements revealed an elevation in the polarization resistance with growth in the inhibitor concentration, which supports the adsorption and inhibition behavior of Cur-AgNp on the steel surface. The inhibitor functioned by adsorption on the steel surface and obeyed the Langmuir kinetic-thermodynamic isotherm with a mixed mode of physical/ chemical adsorption. The potentiodynamic polarization study revealed cathodic predominating behavior. Conclusion: The SEM analysis depicted the development of a protective inhibitor film on the steel substrate, and FTIRATR analysis of the inhibited steel surface supported the adsorption of the corrosion inhibitor on the metallic surface.

In this study, individual Al2O3 and Cr2O3 coatings and Cr2O3-25, 50, 75 wt% Al2O3 composite coatings were applied on carbon steel by atmospheric plasma spraying method. Corrosion experiments were performed on as-sprayed and epoxy resin sealed coatings including potentiodynamic polarization, electrochemical impedance spectroscopy and long-term immersion in 3.5 wt% NaCl solution. Phase composition and microstructure of the coatings were investigated by x-ray diffraction, optical microscopy and scanning electron microscopy, before and after the corrosion experiment. The results showed that the Cr2O3 coating exhibited the best corrosion resistance, due to the densest microstructure and highest adhesion strength. The Cr2O3-25 wt% Al2O3 coating had the highest interconnected porosities and thus had the least corrosion resistance compared to other coatings. In general, the as-sprayed coatings induced a maximum increase of 3.93 times the polarization resistance (Rp) in the polarization experiment and a 3.5 times increase in the charge transfer resistance (Rct) in the EIS experiment, which was not significant. Stresses caused by increased volume of corrosion products in the coating-substrate interface resulted in the spallation of Cr2O3-25, 50 wt% Al2O3 coatings from the substrate over long-term of immersion. The adhesion strength of the coatings was a determining criterion for the long-term durability of the coatings. The sealing treatment resulted in a significant increase in Rp and Rct.

Stainless steel reinforcing rebars and prestressing strands are viable alternatives to carbon steel materials for prestressed concrete structures in extremely aggressive environments. They offer better durability and require less maintenance. This study experimentally investigated the transfer length and prestress losses of 15.2-mm- (0.6-in.-) diameter Duplex High-Strength Stainless Steel (HSSS) strands as well as the shear and flexural behavior of two full-scale 12.8-m- (42-ft-) long AASHTO Type II concrete girders prestressed with HSSS strands and reinforced with duplex stainless steel rebars. The girders were made composite by adding a deck slab. One girder was tested in shear at both ends while the other girder was tested in flexure. Experimental shear and flexural behavior of the girders exhibited a constant increase in load carrying capacity up to failure. The failure mode for the shear tests was web shear, and for the flexural test was rupture of the HSSS strands. Both girders tested in shear and flexure failed in a progressive manner as they exhibited adequate warning through noticeable deflection, excessive cracking, and large reserve strength from first cracking to failure. The applicability of AASHTO LRFD provision for stainless steel reinforcing materials was investigated. AASHTO LRFD equations for flexural resistance were modified to cover rupture of strand failure mode. Experimental shear strength and flexural strength of the girders were greater than the predicted values by AASHTO shear equations and modified AASHTO flexural equations, respectively.

In this present research, optimization of spot-welding process parameters was done on the low carbon steel grade (JSC 590RN) using Taguchi L18 methodology. The main process parameters of spot welding namely electrode diameter (d), electrode force (F), welding current (I) and weld time (t) are taken to determine the quality characteristics of the joint. Heat affected Zone (HAZ), Nugget diameter (N-D) and tensile strength were taken as a quality characteristic for the improvement. For experimental trials, Taguchi L18 was selected. The GRA technique was used to observe the level of importance of process factors on spot welding. ANOVA results show that amid all control factors, welding current (39.19%) is the highest participating followed by weld time (23.81%). In this experiment, the confirmation result shows that it is possible to increases the weld quality up to 12.0081%.

This paper investigates the accuracy of different design equations given in design specifications and literatures in determining the block shear strength of the lean duplex stainless steel fillet welded connections with base metal fracture. It points out the problem inherent in the block shear provision specified in the North American cold-formed design specification, which does not consider shear strain hardening. The previous test results have found that full shear strain hardening can be assumed for the carbon steel and ferritic stainless steel welded connections, but not applicable to the thin-walled lean duplex stainless steel welded connections with a higher ratio of the tensile strength to yield stress. Based on the results of finite element analysis including ductile damage simulation, this study reveals that the block shear strength of the lean duplex stainless steel specimens can be determined accurately using the mean between the shear yield stress and the shear ultimate stress. This paper also investigates the effect of stress triaxiality incorporated in the block shear equations found in the literature through comparative analysis with the bolted connection. The effect is shown to be negligible for the thin-walled lean duplex stainless steel welded connection, although higher stress triaxiality is developed in welded connection than in bolted connection. This paper recommends a block shear equation assuming the normal tensile stress in the net area in conjunction with partial shear strain hardening. The recommended equation was found to be more accurate than other equations for determining the block shear strength of the thin-walled lean duplex stainless steel welded connections.

Corrosion inhibition of Pelargonium (Pe) and Citrus reticulata (Cr) oil concentrates and their admixture (PeCr) on 1018 carbon steel (18CS) was studied in 0.5M H2SO4 and HCl media with electrochemical polarization technique, potential-time evaluation (OCP), coupon computation, optical image assessment, ATF-FTIR spectroscopy and X-ray diffractometry. Polarization data showed Pe performed effectively only at the highest concentrations in H2SO4 (3% and 3.5%) with optimal inhibition performance of 91.56% while in HCl effective corrosion inhibition occurred at all concentrations considered with optimal value of 87.32% at 2.5% concentration. Cr concentrate performed adequately at all concentrations in H2SO4 and HCl solutions with utmost values of 78.12% and 91.87%. PeCr performed more efficiently at all concentrations in HCl with utmost value of 95.46%. PeCr utmost inhibition performance in H2SO4 was below 70%. Coupon measurement showed the concentrate performances in HCl are independent of time/concentration, and generally attained stability from 72 to 96 h of exposure. This contrast their performance in H2SO4 which is significantly dependent on time/concentration. OCP plots shows the presence of Pe in H2SO4 and HCl, Cr in H2SO4 and PeCr in H2SO4 heightens the thermodynamic tendency of 18CS to corrode in view of its optimal inhibition outputs compared to Cr and PeCr in HCl whose plots decreased the thermodynamic tendency. ATF-FTIR data depict significant decrease in transmittance of reactive groups for Cr in H2SO4 and HCl media at all wavenumbers due to adsorption. Transmittance of Pe and PeCr concentrates reactive groups increased after corrosion signifying the nature of their inhibition mechanism. Optical representations of protected and non-inhibited 10CS surfaces substantially differed from each other. X-ray diffractometry identified corrosive precipitates on the steel without concentrate addition. In the presence of the concentrates, in the presence of the concentrates the phases compounds identified on the inhibited steel were non-corrosive.

This study addresses the influence of material variations on the grindability of crankshaft steel. Most previous studies on the effect of material microstructure on grindability involve comparisons of significantly different steel grades. This study, in contrast, is focused on batch-to-batch grindability variations for one steel grade, a scenario frequently occurring in industry where batches from different steel makers are fed into a production line. For this purpose, a batch made of recycled steel and a batch made of ore-based steel were compared with regards to microstructure and grindability under identical grinding and dressing conditions. Although both batches met the same material specifications, microstructural variations were identified in terms of grain size and micro-constituents (inclusions, carbonitrides). While specific grinding energy, residual stress and full-width at half-maximum profiles of ground surfaces were the same for both batches, the recycled batch showed different and unfavorable variation in wheel wear and Barkhausen noise (BN) response. Larger fractions of oxide inclusions and larger grain sizes (affected by carbonitrides) were present in the recycled batch, which were the likely reasons for the differences in wheel wear and BN response, respectively. These findings may aid grindability improvement by steel-grade adjustments, e.g. modification of the distribution and type of inclusions and/or amount of elements forming carbonitrides. Furthermore, the results highlight the importance of understanding and controlling material microstructure, as existing in-line quality by BN control may not always be able to correctly indicate surface integrity, which could lead to misinterpretations (e.g. false part-rejection on the assumption of grinding burn).

Stainless steel (SS) is increasingly used for structural applications in the construction industry as its beneficial properties outweigh initial material costs when sustainability aspects and the whole life cycle of structures are appropriately accounted for in the structural design. Despite the well-recognised significance of connections in bare metallic construction, experimental research on SS beam-to-column connections, especially full-scale test results, are scarce. This paper presents a full-scale experimental investigation on the semi-rigid behaviour of top-seat bolted connection (also known as ‘flange cleat’ connection) made from austenitic SS. Deformation characteristics of various elements of the connection were carefully investigated and subsequently used to calibrate nonlinear FE models for parametric analysis. Obtained numerical results were used to develop a four-parameter power model that relies on simplified expressions for key input parameters to predict the semi-rigid behaviour of bolted top-seat connections. Results predicted using the proposed model and those obtained using currently available techniques based on carbon steel behaviour were compared. Outcomes of the current research highlighted the significance of appropriate inclusion of stain hardening offered by austenitic grade to capture the semi-rigid response of such connections.

The efficiency of Syzygium cumini leaf extract (SCLE) as a corrosion inhibitor was evaluated for carbon steel in 0.5 mol L−1 H2SO4 by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) measurements. It was clearly demonstrated that the inhibition efficiency increased with increasing concentration of leaf extract, due to a decrease in the cathodic currents and blocking of the active corroding sites. The presence of organic molecules from the SCLE on the carbon steel surface was confirmed by FT-IR spectroscopy. The adsorption of species on the alloy surface was modeled using the Langmuir isotherm. A decrease in the carbon steel acid corrosion in the presence of SCLE was also confirmed through contact angle measurements and scanning electron microscopy (SEM).

Background Carbon steel is an important industrial material; its corrosion and protection are attracting more attention from researchers. The use of advanced corrosion inhibitors is widespread due to their accessibility, convenience, and high-efficiency characteristics. In this account, for the first time, the leaves of Achillea Millefolium were extracted using ultrapure water, and the synergistic action of Achillea Millefolium Extract (AME) with zinc ion for carbon steel corrosion in 3.5% NaCl solution was evaluated. Methods Polarization and electrochemical impedance spectroscopy (EIS) experiments were utilized to assess the suggested mixture's inhibition activity. Surface characterizations were carried out using ultraviolet-visible (UV-Vis) analysis, scanning electron microscope (SEM) equipped with EDX, Fourier transmission infrared (FTIR) spectroscopy, contact angle (CA) examination, and grazing incidence X-ray diffraction (GIXRD). Furthermore, DFT and molecular dynamics (MD) simulations were used to explain the inhibition mechanism at the atomic or molecular level. Significant Findings A combined protection attitude was identified, and for 500 ppm Zn + 500 ppm AME, the inhibition effectiveness was 93.49%. Polarization results suggest that the complex behaves as a mixed-type inhibitor, which simultaneously suppresses cathodic and anodic reactions. Surface analysis confirms the protective hydrophobic film formed on the steel surface, all of which demonstrate the outcomes of the electrochemical examination. Our work can provide a theoretical reference for further research on metal-organic-based corrosion inhibitors.

In this paper, low carbon steel sheets were joined by the application of friction stir brazing (FSB) and friction stir vibration brazing (FSVB) processes while %67wt Sn-%33wt Pb alloy was used as filler material and SiO2 nanoparticles were utilized as reinforcing particles. The microstructure and mechanical properties of the developed joints were compared. The results indicated that the presence of mechanical vibration in FSVB promoted metallurgical reaction between the filler and base metals due to the enhanced thermal effect. Shear force for fracture and the joint hardness increased about 25 and 20%, respectively, as FSVB was replaced by FSB. The results also showed that the presence of vibration in FSVB led to the grain size decrease in the joint and enhanced the homogeneity of SiO2 particles distribution. According to fracture analyses, the number of dimples increased and the plasticity of the joint enhanced as FSVB was applied. Wetting of molten filler on substrate steels enhanced while vibration frequency increased. A continuous intermetallic compound layer with a fair thickness was formed as FSVB with a high-frequency value (50 Hz) was applied.

Quenching and partitioning (Q&P) treatment is a novel method to produce advanced high strength steel with excellent mechanical properties. In this study, combination of multiple-cyclic annealing and Q&P process was compared with traditional cold-rolled Q&P steel to investigate the microstructural characteristics and austenite retention. The results showed that retained austenite in traditional Q&P sample was principally located in the exterior of austenite transformation products, while those in multiple-cyclic annealing samples were mainly distributed inside the transformation products. With the increase in cyclic annealing number, both of austenite fraction and austenite carbon content increased, attributing to higher initial austenite carbon content and larger number of austenite/neighbored phase interface to act as carbon partitioning channel. In traditional Q&P sample, the deformed ferrite was recrystallized by sub-grain coalescence, while the austenite was newly nucleated and grew up during annealing process. As a comparison, the ferrite in multiple-cycle annealing samples was formed by means of three routes: tempered martensite that completely recovered with retention of interior martensite variant, epitaxial ferrite that formed on basis of tempered martensite, ferrite that newly nucleated and grew up during the final annealing process. Both of lath martensite and twin martensite were formed as initial martensite and then tempered during partitioning process to precipitate e carbide with C enrichment, Mn enrichment and homogeneous Si distribution. Compared with the traditional cold-rolled Q&P steel, the Q&P specimens after multiple-cyclic annealing show smaller strength and much larger elongation, ascribing to the coarser microstructure and more efficient transformation induced plasticity (TRIP) effect deriving from retained austenite with high carbon content and larger volume fraction. The application of double annealing treatment can optimize the mechanical properties of Q&P steel to show a striking product of strength and elongation as about 29 GPa%, which efficiently exploit the potential of mechanical performance in low carbon steel.

Due to the high moisture content and strong corrosion of oil–gas mixtures, the electrochemical corrosion and perforation leakage of their transportation pipelines occur frequently in the western oil fields of China. Using various methods, this work investigates the failure of an L360NB carbon steel pipeline in detail. The obtained results show that the present leakage and ignition of this pipeline are mainly attributed to the local electrochemical corrosion. In fact, the transported oil–gas mixture in this pipeline is usually composed of H2S and O2, besides CO2 and Cl-. Under their comprehensive actions, the corrosion rate increases, which firstly leads to the perforation and leakage within a local domain. Then, the mechanical friction between the mixture and the insulation layer readily causes static electricity. Consequently, the spontaneous combustion of the corrosion product, FeS, may promote fire formation. In addition, the methods used for removing the H2S gas and corrosion inhibitors are discussed, which provides effective tools for the suppression of the electrochemical corrosion of pipelines.

Welding process is one of the most widely applied processes in the industry. This is due to the ease of the process and it's a quantitative process. The addition of metallic powders to the welding area has not been widely emphasized as a solution to amelioration the tribology characteristic of the welding area therefore the effect of adding metallic powders (SnS nanoparticles) to the welding area on tribology properties was studied. This effect was studied at the values of coefficient of friction, coefficient of wear and wear rate by using the ring – on – disc sliding wear test equipment was used to study the tribological behavior of low carbon steel (A 106 grade B) as pure, 6010 welded and SnS- 6010 welded) under changing loads with constant velocity and in one hour for each run the dry condition at ambient temperature. The results show the coefficient of friction, coefficient of wear and wear rate increased with up load.

The corrosion-resistant on the inner surface of the carbon pipeline welding alloys for two sections of the corrosion-resistant welding alloys (pure welding alloy) and welding alloys added Tin Disulfide Nanoparticles (SnS NPs) were welded by tungsten inert gas welding (TIG). The electrochemical behavior of the weld alloy was investigated at room temperature in 3.5% NaCl solution using potentiodynamic polarization. To reveal the corrosion resistance of alloys welded joints, some significant characterization parameters such as Ecorr, Icorr and in polarization curves were analyzed and compared. The surface morphology of corrosion products was also analyzed by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) for two cases. The results show that the corrosion resistance for welding alloys added SnS Nps appeared high corrosion resistance, lower corrosion rate, and higher protection efficiency by 48% compared with pure welding alloy.

Cathodic protection is a well-known technique to control corrosion of buried structures, even in the presence of a grounding system. In fact, without cathodic protection, the grounded carbon steel ...

The sulphide stress cracking of high strength low alloy (HSLA) carbon steel C110 is related to the hydrogen absorption process. The objective of this research is to evaluate the effect of adsorbed ...

In this work a corrosion protection material formed by commercial benzoxazine and polyaniline (PAni) for coatings applications was developed. PAni doped with a natural phenolic compound, cardanol, was used in the coating preparation, and conventional hydrochloric acid-doped PAni was also used for comparative purposes. Cardanol is a reddish-brown liquid obtained from the by-product of cashew nut processing. The presence of the aliphatic group and the hydroxyl of the cardanol, as well as the amine groups of the PAni, can enhance the corrosion barrier of a benzoxazine coatings. The anticorrosive properties of the coatings were evaluated by electrochemical impedance spectroscopy in 3.5% NaCl solution for a total period of 168 h. The coatings of benzoxazine filled with PAni showed better anticorrosion performance and adhesion strength on carbon steel substrate when compared to pristine benzoxazine and PAni doped with 3 wt% cardanol exhibits the best performances. This last result can be explained by both the presence of PAni and the better PAni dispersion within benzoxazine when doped with cardanol. In addition, the incorporation of cardanol-doped PAni in the benzoxazine reduced the cure temperature of the benzoxazine.

In this study, the carbide precipitation at 925 °C in austenite (γ) of a 0.04C–1.5Mn–0.10Ti–0.39 W (wt%) low-carbon steel was investigated by stress relaxation (SR) high-resolution transmission electron microscopy and atom probe tomography. First-principles calculations were employed to reveal the precipitation mechanism. Results indicate that a high dispersion of W- and Fe-rich MC-type ultrafine carbides (

This work combines a computational and an experimental validation approach to study the feasibility of producing high-quality CoCrFeMnNi high-entropy alloy coatings with the employment of a high-velocity oxy-air-fuel deposition technique. Computational fluid dynamics models were used to predict the maximum speed and temperature for CoCrFeMnNi particles during spraying with the employment of different application temperatures. The coatings were applied to a carbon steel substrate by using three different spraying temperatures. Afterwards, the microstructure, the microhardness, and the porosity of the produced coatings were evaluated. According to the results, the coatings were successfully applied, forming a homogenous FCC phase with good adhesion to the substrate. The different spraying temperatures appear to influence the attained microstructures. As the spraying temperature increases, the volume of oxides increases, in good agreement with the computational fluid dynamics models that can predict accurately the in-flight particle temperature evolution using different spray parameters. HVOF appears to be a suitable technique to fabricate CoCrFeMnNi high-entropy alloy coatings, with high homogeneity, low porosity, and oxidation. Careful selection of the deposition parameters may help to improve the coating quality.

As an innovative method that may change the manufacturing landscape in the near future, submerged arc additive manufacturing (SAAM) offers the benefits of flux protection and an inherent intrinsic heat treatment (IHT) for fabricating large-sized, high toughness parts in-situ. In this study, the influence of interlayer temperature on microstructure and mechanical properties of SAAM-processed low-carbon steel were elucidated with a particular focus on the toughening mechanism subjected to the in-situ IHT, which was first time comprehensively analyzed. Our SAAM-processed steel is found toughened in-situ by raising the critical fracture stress (reducing the effective grain size), and yield strength is also slightly lowered in-situ (softening the matrix), at a readily accessible interlayer temperature of ~200 °C for an optimal strength-toughness combination. This allows for the effective suppression of ductile-brittle transition (ductile-brittle transition temperature: ~ − 108 °C). The superior impact toughness (over 300 J at −60 °C) mainly origins from: (i) the pronounced amount of α-Fe (ferrite, BCC) that are intrinsically soft and facilitate plastic deformation, thereby impede the initiation and propagation of cracks; (ii) the fine-grained structure of multiple-recrystallized α-Fe phase and the increase of high-angle grain boundaries that make energy consumption more easily via tortuous crack propagating; (iii) the dispersedly distributed globular cementite structures formed by the decomposition of lamellar pearlite reduce the microcrack nucleation sites and release the strain concentration. The present SAAM method offers a solution for economically manufacturing large engineering components with uniform mechanical properties that exhibit an irreplaceable role in the low-temperature application with moderate strength requirements but extremely high in toughness.

Previous researches have carried out studying the corrosion behavior of steels, the most frequently used steels are medium carbon steel, alloy steel, and stainless steel. This is due to their wide range of applications. So, corrosion behavior is necessary to be analyzed for every steel type because of its wide function. This study was aimed to analyze the corrosion rate, macrostructure, and the XRD results of the AISI 1045, AISI 4140, and SS 304 which represent every steel type. Then, the steels were exposed to the 0.5M H2SO4 solution with various corrosion times. The variation of the corrosion time was 48, 96, and 144 hours. The results of this study revealed that AISI 1045 showed the highest corrosion rate with the value of 183.7 mpy at 144 hours of the time variation. All specimens obtained an increase in the corrosion rate with the increase in the corrosion time. Furthermore, for the macrostructure results, AISI 1045 and AISI 4140 gave obvious rust on the surface of the specimens for all time variation. The corrosion spots appear in the time variation of 96 and 144 hours for SS 304 specimens. XRD analysis confirmed the presence of metal oxides as corrosion products.

A novel desulphurization technology has been put forward using a dispersed in-situ phases induced by an explosive reaction of a composite ball. A composite ball with this function has been designed...

Low-carbon steel is a common structural material, but additively manufactured structural component of this material is rare due to its inhomogeneous properties. In this article, the wire arc additive manufacturing method was used to achieve near homogeneous properties of a low-carbon steel structural component. The process heat input was optimised for the desired layer geometry, and then the optimal energy was applied with a time delay to deposit individual layers. The time delay was used to achieve cyclic heating and cooling treatment of deposited layers. The best possible robotic tool path movement with multi point arcing was further adopted in the study to achieve proper thermal distribution across the structural component. The microstructure of layers was dominated by quasi-polygonal ferrite morphology and pearlite precipitation, with little variation in quantity across the component. The hardness profile was almost consistent with the average hardness of ∼176.92 HV. The proof stress slightly increases with decrease in grain size and increase in ferrite/pearlite ratio, however, the overall tensile behaviour is homogeneous with average σ0.2, σu and ε% values of 427.78 MPa, 527.89 MPa and 22.31%, respectively. The quasi-ductile fracture was generally occurred due to void coalescence around larger inclusions. The overall analysis showed that more than 90% of homogeneity was achieved in microstructural and mechanical behaviour of the deposited component.

Carbon steel is generally exposed to corrosion in acidic media, thus three nonionic surfactants based on pyrazolopyrimidine derivatives were designed and examined for the first time as inhibitors f...

MS1200 steel grade is now widely utilized in the automotive sector because it is a good solution for the current trend of vehicle chassis frame construction. This research presents a technology procedure for producing MS1200 steel grade from low carbon steel scrap and sponge iron – a product of MIREX Vietnam. The smelting using up to 30 % sponge iron briquettes combined with low carbon scrap, FeSi, FeMn, FeCr, FeTi,… was realized in a medium frequency induction furnace. The heat treatment for forged steel was performed to obtain required properties. The steel product has the following properties: tensile strength σb = 1280 MPa, yield strength σ0.2 = 990 MPa and impact toughness ak = 769 J/mm2, that meets the need of industrial use.

Purpose This paper aims to discover a highly efficient corrosion inhibitor for 45# steel in hydrochloric acid solution and reveal the mechanism of inhibitors. Design/methodology/approach In this paper, electrochemical measurements, weight loss measurements, surface characterization and theoretical calculation are used to evaluate the inhibition performance and reveal the mechanism of inhibitors. Findings Results show that didecyl dimethyl ammonium chloride (DDAC), especially in combination with dodecane phenol plyoxyethylene, could provide a good protection performance for the carbon steel in hydrochloric acid. The N atoms and long alkyl chains in DDAC molecular structure play the vital role. Originality/value Usually, DDAC is used as the compound chemical disinfectant in oilfield sterilization, medicine and health. However, to the best of the authors’ knowledge, no study has shown that it can mitigate the corrosion of carbon steels in HCl solution.