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As a basic mechanical component, the sealing ring is widely used in industrial, aerospatial, and other fields. In this study, an elastic metal C-shaped sealing ring with a wave structure was taken as an example, and its performance was analyzed theoretically and measured experimentally. First, an experimental study was performed on the C-ring seal. The proposed method for experimental measurement of the contact stress of the C-ring seal involved innovative use of a universal electronic testing machine and pressure sensitive paper, in conjunction with the hue&ndash, saturation&ndash, brightness (HSB) method. Based on the discoloration of the pressure sensitive paper after contact stress, computer software was used for analysis, the discoloration was digitized, and the contact stress was established. Second, a theoretical calculation model of the C-ring seal was established using ANSYS software, and a finite element theoretical calculation of the mechanical properties of the sealing ring was established. Finally, the contact stress results were compared with the model calculation results of the C-ring seal. The error between the two was small (4.8%), which proved the validity of the calculation model and the scientificity of the experimental method.

The failure of a proximal humerus internal locking system (PHILOS) used in a pantalar arthrodesis was investigated in this paper. PHILOS constructs are hybrids using locking and non-locking screws. Both the plate and the screws used in the fusion were obtained for analysis. However, only the plate failure analysis is reported in this paper. The implant had failed in several pieces. Optical and scanning electron microscopic analyses were performed to characterize the failure mode(s) and fracture surface. The chemical composition and mechanical properties of the plate were determined and compared to controlling specifications to manufacture the devices. We found that equivalent tensile strength exceeded at the locations of high stress, axial, and angular displacement and matched the specification at the regions of lower stress/displacement. Such a region-wise change in mechanical properties with in vivo utilization has not been reported in the literature. Evidence of inclusions was qualitatively determined for the stainless steel 316L plate failing the specifications. Pitting corrosion, scratches, discoloration and debris were present on the plate. Fracture surface showed (1) multi-site corrosion damage within the screw holes forming a 45° maximum shear force line for crack-linking, and (2) crack propagation perpendicular to the crack forming origin that may have formed due to the presence of inclusions. Fracture features such as beach marks and striations indicating that corrosion may have initiated the crack(s), which grew by fatigue over a period of time. In conclusion, the most likely mechanism of failure for the device was due to corrosion fatigue and lack of bony in-growth on the screws that may have caused loosening of the device causing deformity and pre-mature failure.

The recycling of electronic scrap is an important subject not only from an environmental aspect but also for recovering metal resources such as copper. In this work, the microbial extraction of copper and other metals (Cu, Ni, Co, Fe and Al) present in the depopulated and shredded printed circuit board (PCB) is elaborated. Bacterial strains of A. ferrooxidans, A. thiooxidans and a fungal strain, A. niger are used for copper extraction along with other metals from shredded PCBs. An optimum metal recovery of 93% Cu was obtained at 308 K, pH 2 using 8% pulp density in 10 days by a mixed culture of A. ferrooxidans and A. thiooxidans. Whereas using A. niger, a metal recovery of 66% Cu was reported using similar experimental conditions. The results show the higher potential ability of bacteria as compared to fungus to bioleach copper. Additionally, the kinetics and mechanism of copper bioleaching from this e-waste by the chemolithotrophs and heterotrophs were evaluated. The leach liquor obtained from the optimized leaching process was subjected to separation and purification of copper as &gt, 99% pure copper sulfate using Acorga M5640 by solvent extraction.

An innovative, efficient, and economically viable process for the recycling of spent alkaline batteries is presented herein. The developed process allows for the selective recovery of Zn and Mn metals present in alkaline batteries. The hydrometallurgical process consists of a physical pre-treatment step for separating out the metal powder containing Zn and Mn, followed by a chemical treatment step for the recovery of these metals. Sulfuric acid was used for the first leaching process to dissolve Zn(II) and Mn(II) into the leachate. After purification, Mn was recovered in the form of MnO2, and Zn in its metal form. Furthermore, during the second sulfuric acid leaching, Na2S2O5 was added for the conversion of Mn(IV) to Mn(II) (soluble in the leachate), allowing Mn to be recovered as MnCO3. Masses of 162 kg of Zn metal and 215 kg of Mn (both in the form of MnO2 and MnCO3) were recovered from one ton of spent alkaline batteries. The direct operating costs (chemicals, labor operation, utilities, energy) and indirect costs (amortization, interest payment) required for a plant treating 8 tons of spent batteries per day was calculated to be $CAD 726 and $CAD 534 per ton, respectively, while the total revenue from the sale of the metals was calculated at $CAD 1359.6 per ton of spent batteries. The development of this type of cost-effective industrial process is necessary for a circular economy, as it contributes to addressing environment- and energy-related issues, and creates opportunities for the economic utilization of metals.

The use of lignin can be one of the methods of coke powder substitution in the agglomeration process. This article specifies the material research of lignin and the technological and ecological parameters of the agglomeration process in laboratory conditions using biomass lignin. The methodology of the Raman and infrared spectroscopy, representing a new approach in the analysis and assessment for the purposes of material characteristics for the agglomeration process, was applied to study the structure of carbonaceous matter. The material research of lignin has determined that its calorific value corresponds to ca. 80% of the calorific value of coke powder, while its reactivity is higher than that of the coke. Although the substitution of coke powder using different types of waste biomass (e.g., wood sawdust) in the production of the agglomerate is limited to the maximum of 8&ndash, 15%, in case of lignin, more than 20% can be substituted, while the standard properties of the produced agglomerate are maintained. The lower emissions of sulfur and nitrogen oxides as well as the reduction of carbon footprint in the agglomeration process as a result of the so-called zero CO2 balance in the formation and processing of the biomass represent its positive aspects. Based on the laboratory research of lignin, up to a 50% substitution of coke powder with this type of biomass can be predicted for the technology of agglomerate production in real operation.

In the present investigation, results obtained from the process of the biosorption of Zn(II) in synthetic wastewaters are presented, using three agricultural wastes (coffee pulp, banana pseudo-stem, and corncob). Firstly, the percentage of lignin and cellulose for each material was determined. Then, using the free software XLSTAT, the waste with the highest removal for this metal was selected and, after this, the optimum pH, kinetics, adsorption isotherm, and point of zero charge (pHpzc) were found. Finally, a comparison with other lignocellulosic materials derived from banana, corn, and coffee crops was carried out. According to the results obtained, coffee pulp was the material that showed a high removal compared to the other two (63.58%), for which the optimum pH was 5.0 units. The kinetic model, which was adjusted to the process of biosorption, was the pseudo second order of Ho and McKay, which in turn presented an isotherm of Langmuir&rsquo, s linearized model where the maximum adsorption capacity with that waste was 13.53 mg &times, g&minus, 1, obtained with a particle size of 180 &micro, m, contact time of 90 min at 100 RPM, temperature of 25 &deg, C, and pHpzc 3.95 units. Lastly, the authors state that this type of agricultural waste can be used as a green technology in the treatment of wastewater, particularly in the removal of the aforementioned pollutant, in order to fulfill goals 3.9 and 6.9 of the Sustainable Development Goals of the 2030 Agenda, to the level of challenge of the research, the authors propose for the future to carry out the implementation of this type of waste, without chemical modification, in the treatment of wastewater for the removal of the mentioned pollutant in a pilot study with different wastewaters and industries.

This study proposes a cleaner lead-acid battery (LAB) paste and pyrite cinder (PyC) recycling method without excessive generation of SO2. PyCs were employed as sulfur-fixing reagents to conserve sulfur as condensed sulfides, which prevented SO2 emissions. In this work, the phase transformation mechanisms in a PbSO4-Na2CO3-Fe3O4-C reaction system were studied in detail. Furthermore, the co-treatment of spent LAB and PyCs was conducted to determine the optimal recycling conditions and to detect the influences of different processing parameters on lead recovery and sulfur fixation. In addition, a bench-scale experiment was carried out to confirm the feasibility and reliability of this novel process. The results reveal that the products were separated into three distinct layers: slag, ferrous matte, and crude lead. 98.3% of lead and 99% of silver in the feed materials were directly enriched in crude lead. Crude lead with purity of more than 98 wt.% (weight percent) was obtained by a one-step extraction. Lead contents in the produced matte and slag were below 2.7 wt.% and 0.6 wt.%, respectively. At the same time, 99.2% total sulfur was fixed and recovered.

Porphyry-type deposits are the major sources of copper and molybdenum, and flotation has been adopted to recover them separately. The conventional reagents used for depressing copper minerals, such as NaHS, Na2S, and Nokes reagent, have the potential to emit toxic H2S gas when pulp pH was not properly controlled. Thus, in this study the applicability of microencapsulation (ME) using ferrous and phosphate ions as an alternative process to depress the floatability of chalcopyrite was investigated. During ME treatment, the use of high concentrations of ferrous and phosphate ions together with air introduction increased the amount of FePO4 coating formed on the chalcopyrite surface, which was proportional to the degree of depression of its floatability. Although ME treatment also reduced the floatability of molybdenite, ~92% Mo could be recovered by utilizing emulsified kerosene. Flotation of chalcopyrite/molybdenite mixture confirmed that the separation efficiency was greatly improved from 10.9% to 66.8% by employing ME treatment as a conditioning process for Cu-Mo flotation separation.

Novel and environmentally benign adsorbents were prepared via a simple sulfuric acid treatment process using the wastes of astringent persimmon, a type of biomass waste, along with persimmon tannin extract which is currently employed for the tanning of leather and as natural dyes and paints. The effectiveness of these new biosorbents was exemplified with regards to hydrometallurgical and environmental engineering applications for the adsorptive removal of uranium and thorium from rare earths, cesium from other alkaline metals such as sodium, hexa-valent chromium from zinc as well as adsorptive recovery of gold from chloride media. Furthermore, reductive coagulation of gold from chloride media for the direct recovery of metallic gold and adsorptive recovery of palladium and platinum using chemically modified persimmon tannin extract were studied. OPEN

This study provides an up to date review of tannins, specifically quebracho, in mineral processing and metallurgical processes. Quebracho is a highly useful reagent in many flotation applications, acting as both a depressant and a dispersant. Three different types of quebracho are mentioned in this study; quebracho “S” or Tupasol ATO, quebracho “O” or Tupafin ATO, and quebracho “A” or Silvafloc. It should be noted that literature often refers simply to “quebracho” without distinguishing a specific type. Quebracho is most commonly used in industry as a method to separate fluorite from calcite, which is traditionally quite challenging as both minerals share a common ion—calcium. Other applications for quebracho in flotation with calcite minerals as the main gangue source include barite and scheelite. In sulfide systems, quebracho is a key reagent in differential flotation of copper, lead, zinc circuits. The use of quebracho in the precipitation of germanium from zinc ores and for the recovery of ultrafine gold is also detailed in this work. This analysis explores the wide range of uses and methodology of quebracho in the extractive metallurgy field and expands on previous research by Iskra and Kitchener at Imperial College entitled, “Quebracho in Mineral Processing”.

Hydrometallurgical and pyrometallurgical processes to recover gold (Au) from cell-phone printed circuit boards (PCBs) have the disadvantage of generating corrosive residues and consuming a large amount of energy. Therefore, it is necessary to look for biological processes that have low energy consumption and are friendly to the environment. Among the biological alternatives for the recovery of Au from PCB is the use of cyanogenic bacteria and filamentous fungi in cultures with agitation. Considering that it is important to explore the response of microorganisms in cultures without agitation to reduce energy expenditure in the recovery of metals from PCB, the present investigation evaluated the capacity of Aspergillus niger MXPE6 and a fungal consortium to induce Au bioleaching from PCB in a culture medium with glucose as a carbon source and without agitation (pH 4.5). The results indicate that the treatments with PCB inoculated with the fungal consortium showed a considerable decrease in pH (2.8) in comparison with the treatments inoculated with A. niger MXPE6 (4.0). The fungal consortium showed a significantly higher Au bioleaching (56%) than A. niger MXPE6 (17%). Finally, the use of fungal consortia grown without agitation could be an alternative to recover metals from PCB, saving energy and material resources.

Bauxite residue (BR) is a well promising resource for critical metals, especially scandium (Sc), a rare and expensive metal with increasing applications in advanced technology. Greek BR seems to significantly favor a commercially viable recovery of Sc combining optimized leaching and advanced separation techniques. Leaching with mineral acids emerges as the dominant selection compared to other techniques. This study investigates an optimized leaching condition set for Sc recovery, using the most advantageous option of sulfuric acid. The main target is to develop a leaching scale-up process to be established in the premises of Mytilineos S.A. (formerly Aluminium of Greece, the largest Greek alumina and aluminum producer), taking into account the feed requirements of a subsequent advanced ion exchanged procedure. Several parameters were studied individually or combined in order to achieve high Sc concentration in the leachate and to ensure selectivity, especially concerning iron. The most significant parameters prove to be the solid-to-liquid ratio (S/L), the final pH value, and the leachate&rsquo, s recycling. The proposed process, with low molarities of sulfuric acid and ambient conditions, integrates rapidly, leading to high and selective Sc recovery. Finally, a leaching process flow diagram under continuous operation on an industrial scale is developed.

The pretreatment processes consisting of grinding followed by roasting were investigated to improve the selective leaching of Nd and Dy from neodymium- iron- boron ( NdFeB) magnet scraps. The peaks of Nd( OH) 3 and Fe were observed in XRD results after grinding with NaOH as the amount of water addition increased to 5 cm(3). These results indicate that the components of Nd and Fe in NdFeB magnet could be changed successfully into Nd( OH) 3 and Fe, respectively. In the roasting tests using the ground product, with increasing roasting temperature to 500 degrees C, the peaks of Nd( OH) 3 and Fe disappeared while those of Nd2O(3) and Fe2O(3) were shown. The peaks of NdFeO3 in the sample roasted at 600 degrees C were observed in the XRD pattern. Consequently, 94.2%, 93.1%, 1.0% of Nd, Dy, Fe were leached at 400 rpm and 90 degrees C in 1 kmol . m- 3 acetic acid solution with 1% pulp density using a sample prepared under the following conditions: 15 in stoichiometric molar ratio of NaOH: Nd, 550 rpm in rotational grinding speed, 5 cm3 in water addition, 30 min in grinding time, 400 degrees C and 2 h in roasting temperature and time. The results indicate that the selective leaching of Nd and Dy from NdFeB magnet could be achieved successfully by grinding and then roasting treatments.

In the iron and steel industry, improving the usage amount of New Zealand sea sand ore as a raw material for ironmaking can reduce the production costs of iron and steel enterprises to a certain extent. In this paper, New Zealand sea sand ore without any grinding pretreatment was used as a raw material, oxidized pellets were prepared by using a disc pelletizer, and the effect of sea sand ore on the performance of green pellets and the metallurgical properties of oxidized pellets was investigated. The effects of sea sand ore on the compressive strength, falling strength, compressive strength of oxidized pellets, and reduction performance were mainly investigated. X-Ray Diffraction (XRD) patterns and Scanning Electron Microscope (SEM) analysis methods were used to discuss the influence of sea sand ore on the microstructure of the pellets’ oxidation and reduction process. As the amount of sea sand ore used increased, the compressive strength of green pellets was gradually decreased, and the falling strength of green pellets and the compressive strength of oxidized pellets were gradually increased. When the amount of sea sand ore used was 40%, the reduction swelling index of pellets was 16.31%. The increase of sea sand ore used made the reduction of pellets suppressed and the reduction rate decreased. When the amount of sea sand ore used increased to 40%, the reduction degree of sea sand ore pellets was only 60.06%. The experimental results in this paper provide specific experimental data for the large-scale application of New Zealand sea sand ore in the blast furnace ironmaking process.

The ball valve is an essential piece of equipment in an oil and gas pipeline. The sand particles transported through the pipeline can cause erosion and wear to the ball valve, thus causing it to fail, leading to serious safety hazards. In this paper, the self-designed erosion experiment method was combined with computational fluid dynamics (CFD), while the Euler-Lagrange method was also introduced to optimize the Oka erosion model and Ford particle-wall rebound model. The erosion mechanism and characteristics of the ball valve sealing surface in gas-solid two-phase flow were simulated, while the erosion condition of the specimen was analyzed and compared when exposed to different factors, such as different particle velocities, impact angle, particle size, and specimen materials. The experimental data conformed well to the CFD erosion simulation data, verifying the accuracy of the CFD simulation analysis. The results indicated that the worn surface was caused by various wear mechanisms, while a “stagnation zone” was identified at the center of the specimen. The maximum erosion area, which was U-shaped, was also located at the center. The erosion rate increased in conjunction with an increase in the particle velocity and size, both of which failed to affect the erosion pattern. The erosion rate initially increased, after which it decreased with the impact angle, reaching the maximum value at an impact angle of 30°. This paper summarizes the erosion failure mechanism and characteristics in gas–solid two-phase flow and provides both technical support and a theoretical basis for the on-site maintenance of essential vulnerable parts in the pipeline, such as ball valves.

Hydrogen is nowadays in focus as an energy carrier that is locally emission free. Especially in combination with fuel-cells, hydrogen offers the possibility of a CO2 neutral mobility, provided that the hydrogen is produced with renewable energy. Structural parts of automotive components are often made of steel, but unfortunately they may show degradation of the mechanical properties when in contact with hydrogen. Under certain service conditions, hydrogen uptake into the applied material can occur. To ensure a safe operation of automotive components, it is therefore necessary to investigate the time, temperature and pressure dependent hydrogen uptake of certain steels, e.g., to deduct suitable testing concepts that also consider a long term service application. To investigate the material dependent hydrogen uptake, a tubular autoclave was set-up. The underlying paper describes the set-up of this autoclave that can be pressurised up to 20 MPa at room temperature and can be heated up to a temperature of 250 &deg, C, due to an externally applied heating sleeve. The second focus of the paper is the investigation of the pressure dependent hydrogen solubility of the martensitic stainless steel 1.4418. The autoclave offers a very fast insertion and exertion of samples and therefore has significant advantages compared to commonly larger autoclaves. Results of hydrogen charging experiments are presented, that were conducted on the Nickel-martensitic stainless steel 1.4418. Cylindrical samples 3 mm in diameter and 10 mm in length were hydrogen charged within the autoclave and subsequently measured using thermal desorption spectroscopy (TDS). The results show how hydrogen sorption curves can be effectively collected to investigate its dependence on time, temperature and hydrogen pressure, thus enabling, e.g., the deduction of hydrogen diffusion coefficients and hydrogen pre-charging concepts for material testing.

The paper considers a three-stage technology for angular rolling of the pipe workpiece. This technology facilitates the expansion of the range of flange parts available by eliminating a number of drawbacks of the known methods of metal forming. In the presented paper, we analyze the results of numerical calculations and experiments, as well as the effective deformation values in blank material, using computer simulation in the DEFORM-3D software package. The results of the computer simulation were reached taking into account experimental studies of the rheological properties of copper alloy L68 in the form of a strain hardening curve using the Instron-8850 complex. The results of the ratio of basic geometric dimensions expanded the range of flange parts under investigation and allowed us to consider angular rolling technology with a variable angle of inclination of the rolling roll from a three-stage perspective, especially in small-scale production.

The edge of a hot rolling strip corresponds to the area where surface defects often occur. The morphologies of several common edge defects are similar to one another, thereby leading to easy error detection. To improve the detection accuracy of edge defects, the authors of this paper first classified the common edge defects and then made a dataset of edge defect images on this basis. Subsequently, edge defect recognition models were established on the basis of LeNet-5, AlexNet, and VggNet-16 by using a convolutional neural network as the core. Through multiple groups of training and recognition experiments, the model&rsquo, s accuracy and recognition time of a single defect image were analyzed and compared with recognition models with different learning rates and sample batches. The experimental results showed that the recognition model based on the AlexNet had a maximum accuracy of 93.5%, and the average recognition time of a single defect image was 0.0035 s, which could meet the industry requirement. The research results in this paper provide a new method and thought for the fine detection of edge defects in hot rolling strips and have practical significance for improving the surface quality of hot rolling strips.

The experimental and numerical study of the effects of the recrystallization behavior of austenite model alloys during hot plate rolling on reverse rolling is the main goal of the paper. The computer models that are currently applied for simulation of reverse rolling are not strain-path-sensitive, thus leading to overestimation of the processing parameters outside the accepted process window (e.g., deformation in the partial austenite recrystallization region). Therefore, in this work, a particular focus is put on the investigation of strain path effects that occur during hot rolling and their influence on the microstructure evolution and mechanical properties of microalloyed austenite. Both experimental and numerical techniques are employed in this study, taking advantage of the integrated computational material engineering concept. The combined isotropic&ndash, kinematic hardening model is used for the macroscale predictions to take into account softening effects due to strain reversal. The macroscale model is additionally enriched with the full-field microstructure evolution model within the cellular automata framework. Examples of obtained results, highlighting the role of the strain reversal on the microstructural response, are presented within the paper. The combination of the physical simulation of austenitic model alloys and computer modeling provided new insights into optimization of the processing routes of advanced high-strength steels (AHSS).

The consideration of anisotropic and asymmetric tension-compression behaviour in some materials has proved to be of great importance for the modelling of plastic behaviours that allow for accurate results in sheet metal forming analysis. However, obtaining this compression behaviour of a sheet metal in the principal plane directions is one of the most complex aspects from an experimental point of view. This complexity is notably increased when this behaviour needs to be analysed under high temperature conditions. This paper presents a compression test system with load application in the in-plane sheet directions which is characterised by a relative technical simplicity allowing its application under temperature conditions of up to 750 &deg, C and different strain-rates. Due to the specific test conditions, namely the high temperature, it is not possible to use the common systems for measuring the strains involved and to obtain the stress-strain curve. Therefore, this paper proposes two methods for this purpose. The first is the performance of interrupted tests and measurement of the central cross sections. The second consists of inverse calibration using finite element simulations. The sensitivity of the proposed test methodology is validated through the characterisation, at room temperature, of the compression and tensile behaviour of six materials with different plastic deformation phenomena. In this way, the asymmetric tension-compression phenomena are accurately identified and high compression strains of around 0.3, higher than those existing in the literature, are investigated. A novel test methodology is thus established that is easily applicable for the mechanical characterisation of sheet metal at high temperature.

Based on the three-dimensional (3D) finite element method (FEM) and Taguchi method (TM), this paper analyzes the tooth surface contact stress (TSCS) of spur gears with three different influence factors: tooth profile deviations (TPD), meshing errors (ME) and lead crowning modifications (LCM), especially researching and analyzing the interactions between TPD, ME and LCM and their degree of influence on the TSCS. In this paper, firstly, a 3D FEM model of one pair of engaged teeth is modeled and the mesh of the contact area is refined by FEM software. In the model, the refined area mesh and the non-refined area mesh are connected by multi-point constraint (MPC), at the same time, in order to save the time of the FEM solution on the premise of ensuring the solution&rsquo, s accuracy, the reasonable size of the refined area is studied and confirmed. Secondly, the TSCS analyses of gears with one single influence factor (other factors are all ideal) are carried out. By inputting the values of different levels of one single factor into the FEM model, especially using the real measurement data of TPD, and conducting the TSCS analysis under different torques, the influence degree of one single factor on TSCS is discussed by comparing the ideal model, and it is found that when the influence factors exist alone, each factor has a great influence on the TSCS. Finally, through TM, an orthogonal test is designed for the three influence factors. According to the test results, the interactions between the influence factors and the influence degree of the factors on the TSCS are analyzed when the three factors exist on the gear at the same time, and it is found that the TPD has the greatest influence on the TSCS, followed by the lead crowning modified quantity. The ME is relatively much small, and there is obvious interaction between ME and LCM. In addition, the optimal combination of factor levels is determined, and compared with the original combination of a gear factory, we see that the contact fatigue performance of the gear with the optimal combination is much better. The research of this paper has a certain reference significance for the control of TPD, ME and LCM when machining and assembling the gears.

The coupling bionic surface is generally prepared by laser melting on the surface of a gray iron brake hub, which can allow the brake hub to achieve excellent wear resistance and fatigue resistance. The designs of most previous experiments have been based on independent units that were uniform in their distribution patterns. Although some progress has been made in the optimization of cell features, there is still room for further improvement with respect to bionics and experimental optimization methods. Here, experiments on units with non-uniform distributions of different distances were used to rearrange and combine the bionic elements. This paper is that the original uniform distribution laser melting strengthening model was designed as a non-uniform distribution model, and the heat preservation and tempering strengthening effect of continuous multiple melting strengthening on the microstructure of the melting zone is discussed. The mechanism of crack initiation and the mode of crack propagation were analyzed. The relationship between the internal stress in the melting zone and the crack initiation resistance was also discussed. In this paper, the mechanism of different spacing distribution on the surface of gray cast iron by laser remelting is put forward innovatively and verified by experiments, which provides a solid theoretical basis for the follow-up industrial application.

The flow behavior in the mold has a considerable influence on the final product quality of the strand. In this paper, the variation of flow field, level fluctuation, and liquid slag distribution was analyzed by a hydraulic modeling experiment of a high-speed billet continuous casting mold with and without consideration of hydrostatic pressure and a solidified shell. The results indicate that a mold with hydrostatic pressure and a solidified shell possesses an impact depth shallower by 10&ndash, 30 mm, level fluctuation greater by 3&ndash, 15%, and more active liquid slag layer at different casting speeds than a mold without them. Moreover, the results of the hydraulic modeling with hydrostatic pressure and a solidified shell agree well with those of the numerical simulation. Therefore, the mold flow behavior modeled with hydrostatic pressure and a solidified shell is closer to the actual behavior than that obtained by models without them. The method in this paper contributes to improving the accuracy of the hydraulic modeling experiment and establishing a foundation for further study of continuous casting.

The in-plane biaxial specimen can well reflect the complex stress state of sheet metal. However, there is no standard for small-sized specimens used in the low-power biaxial fatigue testing machine. The main goal of this paper is to apply the finite element method and orthogonal experiment method to design the cruciform specimen, considering the influence of three main parameters including the diameter of the central semispherical thinning area, the minimum thickness of the center and the arm thickness of the specimen. According to the central strain dispersion coefficient and the strain concentration coefficient proposed in this paper, we ensured that the distribution of strain in the gauge area is uniform and the strain it at its maximum value at the same time. The optimized specimen is verified by a biaxial fatigue test with the digital image correlation (DIC) technique. It is found that the fatigue crack appears in the center region, which proves that the optimized specimen can be effectively used for biaxial fatigue test.

A welded stainless steel tube is a component used in several industrial applications. Its manufacturing process needs to follow specific requirements based on reference standards. This calls for a predictive analysis able to face some critical issues affecting the forming process. In this paper, a model was adopted taking into account the tube geometrical parameters that was able to describe the deformation process and define the best industrial practices. In this paper, the effect of different process parameters and geometric constraints on ferritic stainless steel pipe deformation is studied by finite element method (FEM) simulations. The model sensitivity to the input parameters is reported in terms of stress and tube thinning. The feasibility of the simulated process is assessed through the comparison of Forming Limit Diagrams. The comparison between the calculated and experimental results proved this approach to be a useful tool in order to predict and properly design industrial deformation processes.

The paper deals with the subject of diagnostics and the quick repairs of long-term operated metallic materials. Special attention was paid to historical materials, where the structure (e.g., puddle iron) is different from modern structural steels. In such materials, the processes of microstructural degradation occur as a result of several decades of exposure, which could overpass 100 years. In some cases, their intensity can be potentially catastrophic. For this reason, the search for minimally invasive diagnostic methods is ongoing. In this paper, corrosion and fracture toughness tests were conducted, and the results of these studies were presented for two material states: post-operated and normalized (as a state &ldquo, restoring&rdquo, virgin state). Moreover, through the use of modern numerical methods, composite crack-resistant patches have been designed to reduce the stress intensity factors under cyclic loads. As a result, fatigue lifetime was extended (propagation phase) by more than 300%.

This paper presents the results of forced wear simulation of the friction lift guide rails. The forced wear in the case discussed is an effect of plastic strain of the guide rail surface due to emergency braking of the lift. For the purpose of qualitative and quantitative assessment of wear, the authors applied the numerical simulation of a stray magnetic field. Application of this method allowed evaluating the degree of wear based on the stray field changes. Application of this simulation method allowed obtaining satisfactory results of qualitative and quantitative assessment of the guide rail wear. The intention of this paper was to prove that the permanent magnetic field and the stray field can be applied for the efficient detection of the steel guide rail damages and to verify the possibility of making the quantitative assessment related to the guide rail wear degree versus the personal lift service life.

The service life of materials and components exposed to repeated mechanical loads is limited, which is why the understanding of the damage evolution and estimating its fatigue life is of high importance for its technical application. This paper shows how temperature and magnetic field measurement methods can be used to describe the cyclic deformation behaviour of metallic materials and to derive parameters from this, which are used in short&ndash, term methods to calculate the fatigue life. Within the SteBLife (stepped&ndash, bar fatigue life) approach, only three to five fatigue tests with a stepped fatigue specimen are required to determine a complete S&ndash, N or Woehler curve with scatter bands for different failure probabilities. If only a trend S&ndash, N curve is required, the number of tests can be reduced to a single fatigue test only. In the framework of this paper, these approaches will be presented for normalised SAE 1045 (C45E) and quenched and tempered SAE 4140 (42CrMo4) steels.

The paper takes the corrosion fatigue damage of cable or sling in the actual bridge as a starting point. The high-strength steel wire is chosen as the basic component to study the corrosion fatigue failure mode. The service life prediction model is put forward, which provides a basis for future research. In this paper, the S-N curves of the steel wire with the different corrosion degrees are given through fatigue tests of six groups of steel wire under different corrosion conditions. The results show that the higher the corrosion degree, the steeper the S-N curve, and the fatigue life considering corrosion are much lower than that without considering corrosion. Finally, a fatigue life prediction model considering the coupling effect of corrosion fatigue is proposed and embedded into Abaqus v6.14 (Dassault, Paris, French). The calculation results show that the fatigue model considering the corrosion can predict the service life to some extent.

In this work, a plant trial was conducted on an industrial low pressure die casting (LPDC) manufacturing process for the production of aluminum alloy wheels. Various types of data have been acquired, including extensive measurements of temperature at different locations (die, wheel and cooling channels), pressure in cooling channels and size/location of shrinkage porosity in the produced wheels. Moreover, two process conditions were tested in the trial&mdash, one was the standard production process condition and the other was designed to generate shrinkage porosity in wheels by altering the die temperature. The large amount of quantitative data acquired in this study helped us to understand the key transport phenomena occurring in the process, which include: (1) a thorough picture of the evolution in temperature at a large number of discrete locations in the die and the casting, (2) the dynamic and complicated heat transfer in the cooling channels both water-on and water-off stages, associated with boiling water heat transfer. This paper (Part I) presents the results and findings obtained from the process characterization. The follow-on paper (Part II) will introduce the developed modeling methodology based on the data produced from this work.

In the 61 years that niobium has been used in commercial steels, it has proven to be beneficial via several properties, such as strength and toughness. Over this time, numerous studies have been performed and papers published showing that both the strength and toughness can be improved with higher Nb additions. Earlier studies have verified this trend for steels containing up to about 0.04 wt.% Nb. Basic studies have shown that the addition of Nb increases the recrystallization-stop temperature, T5% or Tnr. These same studies have shown that with up to about 0.05 wt.% of Nb, the T5% temperature increases in the range of finish rolling, which is the basis of controlled rolling. These studies also have shown that at very high Nb levels, exceeding approximately 0.06 wt.% Nb, the recrystallization-stop temperature or T5% can increase into the temperature range of rough rolling, and this could result in insufficient grain refinement and recrystallization during rough rolling. However, the question remains as to how much Nb can be added before the detriments outweigh the benefits. While the benefits are easily observed and discussed, the detriments are not. These detriments at high Nb levels include cost, undissolved Nb particles, weldability issues, higher mill loads and roll wear and the lessening of grain refinement that might otherwise occur during plate rough rolling. This loss of grain refinement is important, since coarse grained microstructures often result in failure in the drop weight tear testing of the plate and pipe. The purpose of this paper is to discuss the practical limits of Nb microalloying in controlled rolled low carbon linepipe steels of gauges ranging from 12 to 25 mm in thickness.

China produced 49.2% of the world&rsquo, s total steel production in 2017. From 1990 to 2017, the world&rsquo, s total steel production increased by 850 Mt, of which 87% came from China. After 30 years of rapid expansion, China&rsquo, s steel industry is not expected to increase its production in the medium and long term. In fact, the industry is currently in the stage of industrial restructuring, and great changes will arise in production structure and technical level to solve pressing issues, such as overcapacity, high energy intensity (EI), and carbon emission. These changes will directly affect the global energy consumption and carbon emissions. Thus, a review of China&rsquo, s steel industry is necessary to introduce its current situation and development plan. Therefore, this paper presents an overview of the Chinese steel industry, and factors involved include steel production, production structure, energy consumption, technical level, EI, carbon emission, scrap consumption, etc. In addition, four determinants are analyzed to explain the EI gap between China and the world&rsquo, s advanced level. In addition, comparison of steel industries between China and the world, development plans for energy savings, and emission reduction are also included in this paper to give readers a clear understanding of China&rsquo, s steel industry.

Aluminum alloys can be used in the fabrication of intricate geometry and curved parts for a wide range of uses in aerospace and automotive sectors, where high stiffness and low weight are necessitated. This paper outlines a review of various research investigations on the superplastic behavior of aluminum alloys that have taken place mainly over the past two decades. The influencing factors on aluminum alloys superplasticity, such as initial grain size, deformation temperature, strain rate, microstructure refinement techniques, and addition of trace elements in aluminum alloys, are analyzed here. Since grain boundary sliding is one of the dominant features of aluminum alloys superplasticity, its deformation mechanism and the corresponding value of activation energy are included as a part of discussion. Dislocation motion, diffusion in grains, and near-grain boundary regions being major features of superplasticity, are discussed as important issues. Moreover, the paper also discusses the corresponding values of grain size exponent, stress exponent, solute drag creep and power law creep. Constitutive equations, which are essential for commercial applications and play a vital role in predicting and analyzing the superplastic behavior, are also reviewed here.

This paper specifies the mathematical and physical modelling of the iron sintering process in laboratory conditions. The aim is to get the simplest approach (using thermodynamic software &ldquo, HSC Chemistry&rdquo, version 9, Outokumpu Research Oy, Pori, Finland) that allows one to predict the output parameters based on the initial composition analysis. As a part of the application of mathematical modelling, a mass and thermal balance of combustion of carbonaceous fuels (including biomass) and a mass and thermal balance of high-temperature sintering of an agglomeration charge were determined. The objective of the paper was to point out the advantages of modelling using thermodynamic software and apply the results into a simulation of the sintering process. The outcome of mathematical modelling correlates to the outcome of physical modelling for fuel combustion and the agglomerate production in a laboratory sintering pan. The energy required to reach the desired sintering temperatures and acquire the standard quality of agglomerate was calculated using 4.97% of coke breeze. In a real experiment with the laboratory sintering pan, 4.35% of coke was used. When a biomass fuel with a lower calorific value (lignin) is used in the agglomeration charge, the amount of fuel has to be increased to 5.52% (with 20% substitution of coke). This paper also aimed at predicting methodological tools and defining thermodynamic conditions for creating an interactive simulation. In addition, kinetics should be considered to improve the predicting capabilities of the current model and therefore in further research it will be required to optimise the computational program pursuant to the results of the kinetics experiments.

Statistical modeling, also known as machine learning, has gained increased attention in part due to the Industry 4.0 development. However, a review of the statistical models within the scope of steel processes has not previously been conducted. This paper reviews available statistical models in the literature predicting the Electrical Energy (EE) consumption of the Electric Arc Furnace (EAF). The aim was to structure published data and to bring clarity to the subject in light of challenges and considerations that are imposed by statistical models. These include data complexity and data treatment, model validation and error reporting, choice of input variables, and model transparency with respect to process metallurgy. A majority of the models are never tested on future heats, which essentially renders the models useless in a practical industrial setting. In addition, nonlinear models outperform linear models but lack transparency with regards to which input variables are influencing the EE consumption prediction. Some input variables that heavily influence the EE consumption are rarely used in the models. The scrap composition and additive materials are two such examples. These observed shortcomings have to be correctly addressed in future research applying statistical modeling on steel processes. Lastly, the paper provides three key recommendations for future research applying statistical modeling on steel processes.

Frequency is an important factor influencing the fatigue behavior. Regarding to the dwell fatigue, it corresponds to the effect of rise and fall time, which is also an important issue especially for the safety evaluation of structure parts under dwell fatigue loading, such as the engines of aircrafts and the pressure hulls of deep-sea submersibles. In this paper, the effect of rise and fall time (2 s, 20 s, 110 s, and 200 s) on the dwell fatigue behavior is investigated for a high strength titanium alloy Ti-6Al-2Sn-2Zr-3Mo-X with basket-weave microstructure. It is shown that the dwell fatigue life decreases with increasing the rise and fall time, which could be correlated by a linear relation in log&ndash, log scale for both the specimen with circular cross section and the specimen with square cross section. The rise and fall time has no influence on the crack initiation mechanism by the scanning electron microscope observation. The cracks initiate from the specimen surface and all the fracture surfaces present multiple crack initiation sites. Moreover, the facet characteristic is observed at some crack initiation sites for both the conventional fatigue and dwell fatigue tests. The paper also indicates that the dwell period of the peak stress reduces the fatigue life and the dwell fatigue life seems to be longer for the specimen with circular cross section than that of the specimen with square cross section.

TiAl alloy has become a key element in aerospace and automotive engine development due to its favorable high temperature mechanical properties and low density. In this paper, high performance TiAl alloy was prepared using atomized Ti-48Al-2Cr-8Nb powder by spark plasma sintering. This paper analyzed the variation of density, microstructure, Vickers hardness, and fracture strength of TiAl alloys prepared with spherical pre-alloyed powder (named as SP powder) and pre-alloyed powder after 12 h of ball milling (named as MP powder) at different sintering temperatures. The results indicate that the density, Vickers hardness, and room temperature (25 &deg, C) bending strength of Ti-48Al-2Cr-8Nb alloy sintered using MP powder, are significantly higher than that of TiAl alloy sintered using SP powder. Specifically, the densification temperature of the MP powder sintered specimen is reduced by 100 &deg, C, the Vickers hardness is increased by 15%, and the room temperature bending strength is increased by 51.9% at a sintering temperature of 1250 &deg, C. The microstructure analysis shows that the Ti-48Al-2Cr-8Nb alloy has the best bending strength when it has a fine grain phase structure.

Owing to the continuous deterioration in the quality of iron ore and scrap, there is an increasing focus on improving the Basic Oxygen Furnace (BOF) process to utilize lower grade input materials. The present paper discusses dephosphorization in BOF steelmaking from a data science perspective, which thus enables steelmakers to produce medium and low phosphorus steel grades. In the present study, data from two steel mills (Plant I and Plant II) were collected and various statistical methods were employed to analyze the data. While most operators in steel plants use spreadsheet-based techniques and linear regression to analyze data, this paper discusses on the suitability of selecting various statistical methods, and benchmarking tests to analyze such dephosphorization data sets. The data contains a wide range of operating conditions, both low and high phosphorus input loads, different slag basicity&rsquo, s, different slag chemistries, and different end point temperatures, etc. The predicted phosphorus partition from various statistical models is compared against plant data and verified against previously published research.

In this paper, phase coherence imaging is proposed to improve spatial resolution and signal-to-noise ratio (SNR) of near-surface defects in rails using cross-correlation of ultrasonic diffuse fields. The direct signals acquired by the phased array are often obscured by nonlinear effects. Thus, the output image processed by conventional post-processing algorithms, like total focus method (TFM), has a blind zone close to the array. To overcome this problem, the diffuse fields, which contain spatial phase correlations, are applied to recover Green&rsquo, s function. In addition, with the purpose of improving image quality, the Green&rsquo, s function is further weighted by a special coherent factor, sign coherence factor (SCF), for grating and side lobes suppression. Experiments are conducted on two rails and data acquisition is completed by a commercial 32-element phased array. The quantitative performance comparison of TFM and SCF images is implemented in terms of the array performance indicator (API) and SNR. The results show that the API of SCF is significantly lower than that of TFM. As for SNR, SCF achieved a better SNR than that of TFM. The study in this paper provides an experimental reference for detecting near-surface defects in the rails.

This paper presents the numerical simulation of the Friction stir welding (FSW) process obtained by using the DEFORM 3D software package. Numerical simulations are based on experimental research, welding of aluminum alloy AA6082-T6 by FSW method, which has the thickness of 7.8 mm. The aim of this paper is to determine the reliability of numerical simulations in the FSW process, which is followed by large deformations, where influential geometric and kinematic parameters are varied. Numerical research was done on the basis of the adopted five-phase orthogonal experimental plan with a variety of factors on two levels and repetition at the central point of the plan for four times. The parameters varied in the experiment are: Welding speed v mm/min, a rotation speed of tool &omega, rpm, angle of pin slopes &alpha, o, a diameter of the pin d mm, diameter of the shoulder D mm. During the performing of the FSW process, forces were measured in three normal directions: Axial force Fz, longitudinal force Fx and side force Fy, as well as the temperature in the adopted measuring positions of the workpiece. The experimental results obtained in this way were compared with the numerical experiment in the same adopted measuring positions, i.e., in the paper an analysis and comparison of the obtained experimental and numerical data of the measured forces and the generated temperature field were made.

This paper deals with the development of a cyclic plasticity model suitable for predicting the strain range dependent behavior of austenitic steels. The proposed cyclic plasticity model uses the virtual back-stress variable corresponding to a cyclically stable material under strain control. This new internal variable is defined by means of a memory surface introduced in the stress space. The linear isotropic hardening rule is also superposed. First, the proposed model was validated on experimental data published for the SS304 material (Kang et al. Constitutive modeling of strain range dependent cyclic hardening. Int J Plast 19 (2003) 1801&ndash, 1819). Subsequently, the proposed cyclic plasticity model was applied to own experimental data from uniaxial tests realized on 08Ch18N10T at room temperature. The new cyclic plasticity model can be calibrated by the relatively simple fitting procedure that is described in the paper. A comparison between the results of a numerical simulation and the results of real experiments demonstrates the robustness of the proposed approach.

A two-dimensional (2D) finite element framework for creep damage simulation at the grain boundary level was developed and reported. The rationale for the paper was that creep damage, particularly creep rupture, for most high temperature alloys is due to the cavitation at the grain boundary level, hence there is a need for depicting such phenomenon. In this specific development of the creep damage simulation framework, the material is modeled by grain and GB (grain boundary), separately, where smeared-out grain boundary element is used. The mesh for grain and grain boundary is achieved by using Neper software. This paper includes (1) the computational framework, the existing subroutines, and method applied in this procedure, (2) the numerical and programming implementation of the GB, (3) the development and validation of the creep software, and (4) the application to simulate plane stress Copper&ndash, Antimony alloy. This paper contributes to the development of finite element simulation for creep damage/rupture at a more realistic grain boundary level and contributes to a new understanding of the intrinsic relationship of stress redistribution and creep fracture.

The paper presents the design and implementation of a computer system dedicated to the optimization of a hot strip rolling process. The software system proposed here involves the flexible integration of virtual models of various devices used in the process: furnace, descalers, rolling stands, accelerated cooling systems, and coiler. The user can configure an arbitrary sequence of operations and perform simulations for this sequence. The main idea of the system and its implementation details are described in the paper. Besides the computer science part, the material models describing the rolling parameters, microstructure evolution, phase transformations, and product properties are also presented. Effect of precipitation was accounted for various stages of the rolling cycle. Experimental tests were performed to generate data for identification of the models. These include plastometric tests, two-step compression tests, and dilatometric tests. Following this, physical simulations of rolling cycles were performed on Gleeble 3800 to supply data for the verification and validation of the models. Finally, case studies of modern industrial processes were performed, and the selected results are presented.

The main aim of this paper is to present an environmentally friendly method for aluminum recycling. Development of new recycling technologies in order to increase scrap reuse potential and CO2 emission savings are of the main importance for aluminum circular economy. In this paper, aluminum chips waste was recycled without any remelting phase in order to increase energy and material savings. The presented process is usually called solid state recycling or direct recycling. Solid state recycling process consists of chips cleaning, cold pre-compaction and hot direct extrusion followed by a combination of equal channel angular pressing (ECAP) and heat treatment. Influence of holding time during solid solution treatment and both artificial aging time and temperature on mechanical properties of the recycled EN AW 6082 aluminum chips were investigated. A comprehensive number of the experiments were performed utilizing design of experiments approach and response surface methodology. Regression models were developed for describe the influence of heat treatment parameters for presented solid state recycling process on mechanical properties of the recycled samples. Utilizing novel procedure high quality recycled samples were obtained with mechanical properties comparable with commercially produced EN AW 6082 aluminum alloy in T6 temper condition. Metallographic analysis of the recycled samples was also performed.

The ultra-high-speed magnetic abrasive machining (UHSMAM) process is a surface improvement technique, which has been widely used to minimize the surface accuracy and change the precision morphology of difficult-to-machine materials. Surface integrity plays an important role in the machining process, because it is used to evaluate the high stress and the loaded components on the machined surface. It is important to evaluate the plastically deformed layers in ultra-precision machining surface of material. However, the usual plastic strains in the ultra-precision machining surface are significantly difficult to consider. In this paper, an ultra-high-speed magnetic abrasive machining technique is used to improve the surface accuracy and dimensional accuracy of an AISI 304 bars. Additionally, the subsequent recrystallizations technique is used for measuring the plastic strain on machined surface of AISI 304 bars. The purpose of this paper is to evaluate the effects of an UHSMAM process on the plastic strains and the strain energy of the machined surface, and to evaluate the residual strain in the plastic deformation of AISI 304 bars materials by analyzing a plastically deformed layer. The results showed that the plastic strain of the material did not change after machined by an UHSMAM process. Based on the results, an UHSMAM process could significantly improve the surface roughness, micro-diameter, and removal weight of AISI 304 bars effectively. The surface roughness Ra of AISI 304 bars was improved from 0.32 &micro, m to 0.03 &micro, m for 40 s of machining time at 80,000 rpm of workpiece revolution speed.

This paper investigates a severe microbiologically influenced failure in the elbows of a buried amine pipeline in a petrochemical plant. Pipelines can experience different corrosion mechanisms, including microbiologically influenced corrosion (MIC). MIC, a form of biodeterioration initiated by microorganisms, can have a devastating impact on the reliability and lifetime of buried installations. This paper provides a systematic investigation of a severe MIC-related failure in a buried amine pipeline and includes a detailed microstructural analysis, corrosion products/biofilm analyses, and monitoring of the presence of causative microorganisms. Conclusions were drawn based on experimental data, obtained from visual observations, optical/electron microscopy, and Energy-dispersive X-ray spectroscopy (EDS)/X-Ray Diffraction (XRD) analyses. Additionally, monitoring the presence of causative microorganisms, especially sulfate-reducing bacteria which play the main role in corrosion, was performed. The results confirmed that the failure, in this case, is attributable to sulfate-reducing bacteria (SRB), which is a long-known key group of microorganisms when it comes to microbial corrosion.

In this paper, an experimental investigation, based on force special parameters, is adopted to analyze the relationship between the milling tool and adhesive phenomena in milling C17200. Generally speaking, the adhesive characteristics, force fluctuations, and tool failure are the main factors affecting the impact of the cutting process on tool wear patterns. However, difficult-to-cut materials, such as the beryllium&ndash, copper alloy C17200, require machining processes with tools with lives that are difficult to predict, due to their excellent mechanical properties. To analyze the tool failure process, a series of experiments based on cutting speed and tool geometry are presented in this paper to observe the adhesive effect on tool flank surfaces and force fluctuations. The results show that the variation of special force parameters in different directions reveals that the thermal&ndash, mechanical effect on sticking substances reached a possible peak value, with inflection points in different parameters at 200 m/min. The sticking substances and tool surfaces (observed by energy disperse spectroscopy and scanning electron microscope), wear capacity, and back-scattered electron imaging also confirmed that adhesion in the wear zone reached a peak value at 200 m/min in the cutting process, exacerbating the adhesive effect on tool failure.

The present study focused on the behaviour of the AW-6060 aluminium alloy in peak temper condition T6 under a wide range of loads: tensile loading, projectile and explosion. The alloy is used as a structural component of civil engineering structures exposed to static or dynamic loads. Therefore, it was crucial to determine the material&rsquo, s behaviour at low and intermediate rates of deformation. Despite the fact that the evaluation of the strain rate sensitivity of the AW-6060 aluminium alloy has already been discussed in literature, the authors of this paper wished to further investigate this topic. They conducted tensile tests and confirmed the thesis that the AW-6060 T6 aluminium alloy has low strain rate sensitivity at room temperature. In addition, the fracture surfaces subjected to different loading (tensile loading, projectile and explosion) were investigated and compared using a scanning electron microscope, because the authors of this paper were trying to develop a new methodology for predicting how samples had been loaded before failure occurred based on scanning electron microscopy (SEM) micrographs. Projectile and explosion tests were performed mainly for the SEM observation of the fracture surfaces. These tests were unconventional and they represent the originality of this research. It was found that the type of loading had an impact on the fracture surface.

In this paper, the viewpoint that maximum resolved shear stress corresponding to the two slip systems in a nickel-based single crystal high-temperature fatigue experiment works together was put forward. A nickel-based single crystal fatigue life prediction model based on modified resolved shear stress amplitude was proposed. For the four groups of fatigue data, eight classical fatigue life prediction models were compared with the model proposed in this paper. Strain parameter is poor in fatigue life prediction as a damage parameter. The life prediction results of the fatigue life prediction model with stress amplitude as the damage parameter, the fatigue life prediction model with maximum resolved shear stress in 30 slip directions as the damage parameter, and the McDiarmid (McD) model, are better. The model proposed in this paper has higher life prediction accuracy.

Infrastructures and industrial buildings are commonly exposed to aggressive environments and damaged by corrosion. In prestressed reinforced concrete structures, the potential risks of corrosion could be severe since reinforcements are already subjected to high amounts of stress and, consequently, their load-bearing capacity could abruptly decrease. In recent years, some experimental studies have been conducted to explore the flexural behavior of corroded pretensioned reinforced concrete (PRC) beams, investigating several aspects of residual structural performance. Although many studies have been done in this area, there is no concise paper reviewing the state-of-the-art research. Accordingly, the main objective of this paper is to provide a review of the available experimental tests for residual capacity assessment of corroded PRC beams. Based on the state-of-the-art review, a degradation law for the flexural strength of corroded PRC beams is suggested. The work is part of the research project “OPTION-Effect of corrosion on prestressed reinforced concrete beam” between OsloMet–Oslo Metropolitan University and Niccolò Cusano University. OPTION has received funding from the Department of Civil Engineering and Energy Technology, OsloMet–Oslo Metropolitan University.