Journal of Metallurgy has retracted the article titled “Inhibition Effect of Substituted iadiazoles on Corrosion Activity of N80 Steel in HCl Solution” [1]. e article was found to contain images reused in several other articles published by Mahendra Yadav and colleagues. e details of the reuse of images are as follows: Figure 9(b) is similar to Figure 11b in [2], Figure 17b in [3], Figure 14b in [4], and Figure 5b in [5]. Figure 9(c) is similar to Figure 11c in [2], Figure 17c in [3], and Figure 14c in [4]. In particular, Figure 9 in [1] shares the same image of a sample in HCl as Figure 11 in [2] and the same image in the presence of an inhibitor, but these represent different inhibitors in each article, AMPT, and BAL, respectively. We asked the authors to provide the underlying uncropped and unadjusted scanning electron microscopy (SEM) images, the raw data, and details of how the experiments were conducted. e corresponding author, Dr. Yadav, said the SEM work was outsourced but did not give details on where, when, or by whom this work was performed. e equipment is described as a “JEOL JSM-6380 LA analytical scanning electron microscope” in this article. However, there is no description of the scanning electron microscope in [2] and in [6] it is described as a “Scanning Electron Microscope model SEM Jeol JSM-5800.” ese are not the same model of microscope, despite these articles sharing some of the same SEM images. Dr. Yadav provided uswith replacement figures.However, they were identical for two of the articles, [1, 6], despite representing experiments with the inhibitors AMPT and ODAEODI, respectively. We were not told how these images were generated, the images were of low resolution, and the text in the images was illegible. e corresponding author agreed to retraction and we have asked the institution to formally investigate. References
The nitriding behavior of austenitic stainless steels (AISI 304 and 316) was studied by different cold work degree (0% (after heat treated), 10%, 20%, 30%, and 40%) before nitride processing. The microstructure, layer thickness, hardness, and chemical microcomposition were evaluated employing optical microscopy, Vickers hardness, and scanning electron microscopy techniques (WDS microanalysis). The initial cold work (previous plastic deformations) in both AISI 304 and 306 austenitic stainless steels does not show special influence in all applied nitriding kinetics (in layer thicknesses). The nitriding processes have formed two layers, one external layer formed by expanded austenite with high nitrogen content, followed by another thinner layer just below formed by expanded austenite with a high presence of carbon (back diffusion). An enhanced diffusion can be observed on AISI 304 steel comparing with AISI 316 steel (a nitrided layer thicker can be noticed in the AISI 304 steel). The mechanical strength of both steels after nitriding processes reveals significant hardness values, almost 1100 HV, on the nitrided layers.
A systematic study on the structural and magnetic properties of Fe 100− x Co x alloys (10 < x < 90, Δ x = 10 in wt. percent) obtained by mechanical alloying is presented. Elemental powders of Fe and Co mixed in an adequate weight ratio were milled at room temperature in a shaker mixer mill using vials and balls of hardened steel as milling media with a ball : powder weight ratio of 12 : 1. The mixtures were milled for 3 h. The results show that, after milling, for almost all the composition (up to x = 60), solid solutions based on bcc structures were obtained. For Co-rich alloys ( x ≥ 70), different phases were found, revealing the formation of a metastable intermetallic phase (FeCo, wairauite) together with fcc-Co and hcp-Co phases. The specific saturation magnetization increases by increasing Co content, reaching a maximum value of 225 emu/g for hcp-Fe 70 Co 30 , and then it shows a diminution up to 154 emu/g for bcc-Fe 30 Co 70 . All studied alloys (Fe 100− x Co x ) present low coercivity, in the range from 0 to 65 Oe, which is lower than reported. The coercivity increases with the increment in Co, reaching a maximum of 64.1 Oe for Fe 40 Co 60 . After that, the coercivity falls up to 24.5 Oe for Co-rich alloys, which make them a very low coercive material.
This research work presents a machinability study between wrought grade titanium and selective laser melted (SLM) titanium Ti-6Al-4V in a face turning operation, machined at cutting speeds between 60 and 180 m/min. Machinability characteristics such as tool wear, cutting forces, and machined surface quality were investigated. Coating delamination, adhesion, abrasion, attrition, and chipping wear mechanisms were dominant during machining of SLM Ti-6Al-4V. Maximum flank wear was found higher in machining SLM Ti-6Al-4V compared to wrought Ti-6Al-4V at all speeds. It was also found that high machining speeds lead to catastrophic failure of the cutting tool during machining of SLM Ti-6Al-4V. Cutting force was higher in machining SLM Ti-6Al-4V as compared to wrought Ti-6Al-4V for all cutting speeds due to its higher strength and hardness. Surface finish improved with the cutting speed despite the high tool wear observed at high machining speeds. Overall, machinability of SLM Ti-6Al-4V was found poor as compared to the wrought alloy.
Nowadays near-net-shape casting technology is an important area of research in the iron and steel industry. Among different kinds of near-net-shape casting process, twin-roll casting process has received much attention among researchers. Twin-roll casting (TRC) has been the subject of extensive research, not only to develop the technology but also to achieve an understanding of microstructural evolution and to produce quality strips. The main issues concerning the design and operation of twin-roll casters are metal-mold heat transfer, metal delivery system, and their possible effects on the solid shell formation and characteristics of the strips. The present review gives an idea about the process aspect, modeling, and quality issues in vertical twin-roll strip casting process and helps to improve the design of twin-roll strip caster.
The fact that the microstructure of steel depends on its composition and the heat treatment given to it has been heavily exploited in the design of steel for power plant applications. To obtain a steel that can function at the higher temperature where power plants operate without failure for extended life, heat treatment is needed to produce fine and highly stable dispersion of carbides, nitrides, and intermetallic compounds in the microstructure of the material. A significant contribution also comes from solid solution strengthening by substitutional solutes. We review here various types of phases, microstructures, functions, and interacting effects of the various alloying elements in the design of steel for modern power plant application.
This study examined the through-thickness (z-direction) compressive stress versus strain behavior of 99.76% commercially pure (grade II) titanium sheet with relatively small grain size. The current study complemented earlier compression studies by examining a very thin (1.60 mm) sheet and deforming the Ti by successive compression tests to relatively large strains. The low aspect ratio, of the compression specimens extracted from the sheet, led to frictional effects that can create high triaxial stresses complicating the uniaxial stress versus strain behavior analysis. Nonetheless, reasonable estimates were made of the through-thickness large-strain behavior of a commercially pure (grade II) thin Ti sheet to relatively large true strains of about 1.0.
Inferior surface quality is a significant problem faced by machinist. The purpose of this study is to present a surface texture analysis undertaken as part of machinability assessment of Super Austenitic Stainless Steel alloy-AL6XN. The surface texture analysis includes measuring the surface roughness and investigating the microstructural behaviour of the machined surfaces. Eight milling trials were conducted using combination of cutting parameters under wet machining. An optical profilometer (noncontact) was used to evaluate the surface texture at three positions. The surface texture was represented using the parameter, average surface roughness. Scanning Electron Microscope was utilised to inspect the machined surface microstructure and correlate the microstructure with the surface roughness. Results showed that maximum roughness values recorded at the three positions in the longitudinal direction (perpendicular to the machining grooves) were 1.21 μm (trial 1), 1.63 μm (trial 6), and 1.68 μm (trial 7), respectively, whereas the roughness values were greatly reduced in the lateral direction. Also, results showed that the feed rate parameter significantly influences the roughness values compared to the other cutting parameters. The microstructure of the machined surfaces was distorted by the existence of cracks, deformed edges, and bands and wear deposition due to machining process.
We developed a unique three-point bend testing apparatus to measure bulk mechanical properties of a model metallic glass alloy (SAM2X5 with nominal composition Fe49.7Cr17.1Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) prepared by spark plasma sintering. The relatively large sample sizes in the present work allowed for the preparation of test specimens with a macroscale cross section (in the millimeter range) with well-controlled sample dimensions closer to standardized tests. Wire saw cutting allowed for a relatively sharp notch radius (3x smaller than previous studies) and minimal sample damage. We determined that Young’s modulus and notch fracture toughness measured by our three-point bending apparatus are 230 GPa and 4.9 MPa·m1/2. Also, Vickers indentation and flexure testing provided consistent results for Young’s modulus. Indentation fracture toughness measured by Vickers indentation produced values at least 50% lower than by flexure. The microscale mechanical properties testing technique presented in this work and subsequent analyses are applicable to specimens of other compositions or ones prepared by other methods.
An anticorrosion activity of 8-quinoline sulphonyl chloride (8-QSC) on mild steel in 1 M HCl solution was studied by weight loss (WL) method and electrochemical methods, namely, electrochemical impedance spectroscopy (EIS), Tafel polarization (TP), and linear polarization resistance (LPR). Results obtained from WL method, EIS, TP, and LPR, showed that 8-QSC is a good corrosion inhibitor for mild steel in 1 M HCl solution. The results indicated that the inhibition efficiency and extent of surface coverage were increased with increase in inhibitor concentration and decrease in the corrosion rate. This is due to the formation of protective film on the surface of mild steel. Adsorption of 8-QSC on the mild steel surface was found to obey the Langmuir adsorption isotherm. A Tafel plot indicates that the used inhibitor behaves predominantly as cathodic type. The surface morphology of the mild steel was studied by Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) Spectroscopy techniques. All the methods give the same order of inhibition efficiencies.
Mill scale is one of waste materials which is produced as a result of hot rolling of steel in all steel companies. On the other hand, mill scale is considered a rich iron source with minimum impurities. This work aims at conversion of mill scale by adjusting smelting processes to produce different valuable products. The smelting processes were carried out using carbothermic reduction in a submerged arc furnace. Two carbonaceous reducing agents and different fluxing materials have been used to adapt optimum smelting process condition. A maximum iron recovery of 83% was obtained by using graphite compared with 76% obtained by using coke. Low sulphur content (≤0.02 wt% S) can be attained by using graphite as a reducing agent in amount that equals or exceeds the stoichiometric molar ratio. By using coke, the highest degree of desulfurization of 97.8% and much lower content of sulphur in the castable metal (0.0028 wt% S) were obtained by controlling the type and quantity of the flux. The results reveal that mill scale waste can be converted into valuable products such as high purity iron as alternative to Sorelmetal used in ductile iron production, low carbon steel, and free cutting steel.
The effects of temperature, pH, and time variations on the protective amount and quality of electroless nickel (EN) deposition on cast aluminium alloy (CAA) substrates were studied. The temperature, pH, and plating time were varied while the surface condition of the substrate was kept constant in acid or alkaline bath. Within solution pH of 5.0–5.5 range, the best quality is obtained in acid solution pH of 5.2. At lower pH (5.0–5.1), good adhesion characterised the EN deposition. Within the range of plating solution pH of 7.0 to 11.5, the highest quantity and quality of EN deposition are obtained on CAA substrate in solution pH of 10.5. It is characterised with few pores and discontinuous metallic EN film. The quantity of EN deposition is time dependent, whereas the adhesion and brightness are not time controlled. The best fit models were developed from the trends of result data obtained from the experiments. The surface morphologies and the chemical composition of the coating were studied using the Jeol JSM-7600F field emission scanning electron microscope.
The main objective of the current work is to investigate the influence of different inoculation conditions on the microstructure and mechanical properties of heavy section ductile iron (DI) castings. Inoculation treatment was done via one step and double step treatments with different amounts of inoculants. The mechanical properties of the fabricated samples were evaluated. The best inoculation procedure in terms of graphite nodules characteristics and mechanical properties was double inoculation with 0.8% inoculants added at first and 0.2% in the late inoculation step. The presence of Sb in one of the cast alloys controlled the growth of graphite nodules in these heavy section ductile iron castings; however low impact toughness was recorded. The matrix structure of ductile cast iron showed a significant influence not only on the strength and impact properties but also on the fracture mode during testing.
In the current study, a factorial design is used to investigate the effect of total iron and silica on the metallurgical performance of different grades of manganese ores. The derived mathematical formulations are applied to estimate the reduction disintegration index (RDI+6.3, RDI+3.15, and RDI−0.5), reduction index (total reduction index (RIT), manganese reduction index (RIM), and iron reduction index (RIF)), and softening-melting property (start of softening (TS1), end of softening (TS2), start of melting (Tm1), and end of melting (Tm2)) of manganese ores. The RDI+6.3 and RDI+3.15 are increased with the individual effect of SiO2 and the interaction effect of iron with silica, while they are decreased as the total iron increased. The high-Fe high-SiO2 manganese ore showed the highest RIT and RIF. The RIM was almost identical in all manganese ores. The presence of high content of SiO2 resulted in a narrow softening range (62–83°C), while the high-Fe high-SiO2 manganese ore exhibited a wider softening range (135–140°C). The melting range was very small in high-Fe low-SiO2 (3–16°C) and high-Fe high-SiO2 (6–8°C) manganese ores, while the low-Fe low-SiO2 manganese ore showed wider melting range (72–74°C). The derived mathematical models are in a good agreement with the experimental results. The calculations are carried out using Matlab program.
Steel Melting Shop-I, Rourkela Steel Plant, Rourkela, produces 0.5 MT of various special steels through BOF-VAR/VOR-LF-CC route. One of the most serious problems in BOF operations was lance skulling, hood jamming, and build-up of metal in the mouth and cone of the furnace due to spitting and slopping. As spitting occurring during blowing increases, these particles of metal are deposited inside the mouth and cone and affect badly BOF productivity. In the present work, control of spitting has been established by addition of sinter during the period of spitting. It also helped to improve the slag formation and fluidity of slag through increase of FeO content during peak decarburisation period.
The tests of uniaxial tensile by 10, 20, and 30% at strain rates of 0.1, 1, 60, 120, and 300 mm/min in rolling direction and transverse direction of recrystallized cold-rolled low-carbon steel sheets were carried out. The effect of rate and degree of deformation on the texture, structure, and mechanical properties were studied. The texture transformations and the growth of the anisotropy of mechanical properties with increasing strain rate up to 120 mm/min are explained by the effect of crystallographic intragranular slip and twinning of deformation mechanism. The further increase of deformation rate leads to texture scattering and decreasing of properties anisotropy, which are bound to the difficulty of intragranular sliding and activation of grain boundary sliding.
Low carbon ferromanganese was nitrided through gas-solid reaction. The nitriding process has been carried out on lab scale at temperature range 800°C–950°C at different nitrogen pressures. Temperature, time, and partial nitrogen pressure of nitriding process of fine low carbon ferromanganese were investigated. Nitrogen content, in weight percent, was more than 9%. MATLAB software was used to derive mathematical model to predict nitrogen content as a function of temperature and nitrogen pressure. According to derived model, nitrogen content can be calculated by the following equation: N content,wt.%=(-30.8882+0.0326*T)/(1+e-((P+0.0038*T-8.4155)/(3.6374-0.0018*T))), where, T is nitriding temperature in K and P is nitrogen pressure in bar. The experimental results are in good agreement with the predicted results. The results showed that nitrogen content, at steady state, is mainly depending on temperature and pressure of nitriding process. MATLAB is a good tool to make precision mathematical model.
Three stainless steel grades with different vanadium content were produced in open induction furnace. The base chemical composition of investigated stainless steel has contained 18.48–18.75% Cr, 5.17–5.62% Mn, 2.47–2.58% Mo, and 6.39–6.64% Ni. The vanadium contents of the three stainless steel grades were 0.009%, 0.112%, and 0.189%. The proposed stainless steels were casted at temperatures 1753 K and 1833 K. The nitrogen contents were determined for the produced steel grades at every cast temperature. The determined nitrogen contents were compared with those calculated from the developed equation of Grigorenko and Pomarin. The influence of cast temperature and vanadium content on nitrogen solubility was investigated. Interpretation between experimental and calculated nitrogen content was carried out. Increasing vanadium content and decreasing cast temperature were found to have positive significant effect on the nitrogen solubility. There were great deviations between experimental results and those calculated by Grigorenko and Pomarin equation.
Metal matrix composites, based on AA6061 reinforced with 60 vol% Al2O3 spherical particles, were produced by gas pressure infiltration and characterized for hardness, impulse excitation modulus, tensile properties (at room temperature and at 250°C), and machining. It was experimentally demonstrated that the novel alumina powder used in the present work does not react with the liquid Mg-containing matrix during the infiltration process. The AA6061 matrix therefore retains its ability to be strengthened by precipitation heat treatment. The latter behaviour combined with the spherical particle shape confers the studied material higher strength and better machinability in comparison with similar composites produced using standard angular alumina particles. The overall features are promising for applications in the aerospace industry, where light and strong materials are required.
The influence of heat treatment on microstructure and mechanical properties of high chromium white cast iron alloyed with titanium was investigated. The austenitizing temperatures of 980°C and 1150°C for 1 hour each followed by tempering at 260°C for 2 hours have been performed and the effect of these treatments on wear resistance/impact toughness combination is reported. The microstructure of irons austenitized at 1150°C showed a fine precipitate of secondary carbides (M6C23) in a matrix of eutectic austenite and eutectic carbides (M7C3). At 980°C, the structure consisted of spheroidal martensite matrix, small amounts of fine secondary carbides, and eutectic carbides. Titanium carbides (TiC) particles with cuboidal morphology were uniformly distributed in both matrices. Irons austenitized at 980°C showed relatively higher tensile strength compared to those austenitized at 1150°C, while the latter showed higher impact toughness. For both cases, optimum tensile strength was reported for the irons alloyed with 1.31% Ti, whereas maximum impact toughness was obtained for the irons without Ti-addition. Higher wear resistance was obtained for the samples austenitized at 980°C compared to the irons treated at 1150°C. For both treatments, optimum wear resistance was obtained with 1.3% Ti.
