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Punyamueang, Suttirat, i Vitoon Uthaisangsuk. "Determination of Stress-Strain Curve of Dual Phase Steel by Nanoindentation Technique". Key Engineering Materials 658 (lipiec 2015): 195–201. http://dx.doi.org/10.4028/www.scientific.net/kem.658.195.
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The advanced high strength (AHS) steels, for example, dual phase (DP) steels, transformation induced plasticity (TRIP) steels and complex (CP) steels principally exhibit multiphase microstructure features. Thus, mechanical behavior of the constituent phases significantly affects the resulting overall properties of such AHS steels. Novel material characterization techniques on micro- and nano-scale have become greatly more important. In this work, stress-strain response of the DP steel grade 1000 was determined by using the Nanoindentation testing. The DP steel showed the microstructure containing finely distributed martensite islands of about 50% phase fraction in the ferritic matrix. The nano-hardness measurements were firstly performed on each individual phase of the examined steel. In parallel, finite element (FE) simulations of the corresponding nano-indentation tests were carried out. Flow curves of the single ferritic and martensitic phases were defined according to a dislocation based theory. Afterwards, the load and penetration depth curves resulted from the experiments and simulations were compared. By this manner, the proper stress-strain responses of both phases were identified and verified. Finally, the effective stress-strain curve of the investigated DP steel could be determined by using 2D representative volume element (RVE) model.
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Peraprutchaya, Yachita, i Surasak Suranantchai. "Finite Element Simulation of Forming Process for Automotive Components from Advanced High Strength Steel". MATEC Web of Conferences 257 (2019): 02010. http://dx.doi.org/10.1051/matecconf/201925702010.
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Advance high strength (AHS) steel has been widely used in the automotive industry and order to reduce the weight of automotive components that effect to reduce fuel consumption, but vehicles maintain safety. However, forming process with AHS steel has many problems which the main defect was spring-back. Therefore, the usage of finite element (FE) method simulation with kinematic hardening materials model sustains and improve production processes. Yoshida-Uemori (Y-U) model is the one of kinematic hardening materials model that show the great capability for prediction of elastic recovery behavior. Consequencely, this work has been research on AHS steel as the NSC980D grade for automotive components in the drawing process and applied FE simulation with Y-U model to improve the production process. Moreover, NSC980D steel was inspected in tension-compression and tensile tests were proceeded. As a result, material parameters from testing simulate with designed die and improvement were shown. Finally, comparing FE simulation forming with experiment forming, showed FE simulation with Y-U model is suitable for prediction and process improvement.
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Panich, Sansot, Vitoon Uthaisangsuk, Surasak Suranuntchai i Suwat Jirathearanat. "Determination of Damage Criterion Using a Hybrid Analysis for Advanced High Strength Steel". Advanced Materials Research 849 (listopad 2013): 200–206. http://dx.doi.org/10.4028/www.scientific.net/amr.849.200.
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Advanced High Strength (AHS) steels have been increasingly applied in the automotive industries due to their distinguished mechanical properties. Microstructures of these steels play an important role and are designed by constituent phases with distinct characteristics. AHS steels exhibit sophisticated damage mechanisms that complicate the prediction of material formability. In this work, Ductile Crack Initiation Locus (DCIL) was developed for describing failure behavior of dual phase steel sheet. A hybrid experimental and numerical analysis was used to determine the DCIL. Tensile tests of various sample geometries were experimentally carried out and crack initiation occurred during forming was identified by the Direct Current Potential Drop (DCPD) method. Then, FE simulations of the corresponding tests were performed to evaluate local stress triaxialities and equivalent plastic strains of the critical area. The damage curves for both crack initiation and localized necking were obtained. Additionally, the von Mises, Hill48 and Yld2000-2d yield criterion were defined in the calculations in order to examine effect of yield model on the resulted curves. To verify applicability of the damage curves, Nakazima test of uniaxial sample was taken into account.
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Jabłońska, M. B. "Mechanical Properties and Fractographic Analysis of High Manganese Steels After Dynamic Deformation Tests". Archives of Metallurgy and Materials 59, nr 3 (28.10.2014): 1193–97. http://dx.doi.org/10.2478/amm-2014-0207.
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Abstract Since few years many research centres conducting research on the development of high-manganese steels for manufacturing of parts for automotive and railway industry. Some of these steels belong to the group of AHS possessing together with high strength a great plastic elongation, and an ideal uniform work hardening behavior. The article presents the dynamic mechanical properties of two types of high manganese austenitic steel with using a flywheel machine at room temperature with strain rates between 5×102÷3.5×103s?–1. It was found that the both studied steels exhibit a high sensitivity Rm to the strain rate. With increasing the strain rate from 5×102 to 3.5×103s?–1 the hardening dominates the process. The fracture analysis indicate that after dynamic test both steel is characterized by ductile fracture surfaces which indicate good plasticity of investigated steels.
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Venturini, Roberto, Paolo Daniele Avancini, Nicola Barbier i Alessandro Rizzi. "Arvedi ESP Technology - The Hot Rolling of HS and AHS Thin Gauge Steel Strips". Materials Science Forum 854 (maj 2016): 42–47. http://dx.doi.org/10.4028/www.scientific.net/msf.854.42.
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After 5 years from start-up, Arvedi ESP Technology has achieved outstanding performances in terms of production, products and quality. The technology has proved particularly suitable for the production of thin gauge strips (< 2 mm). This paper presents the experiences in the production of high strength and advanced high strength steels, such as micro-alloyed S550MC, dual phase DP600 and ferritic bainitic HR60 in thin gauge strips on the ESP line of Acciaieria Arvedi S.p.A. in Cremona. Some aspects of the industrial production process for these steel grades are highlighted on the basis of casting and rolling parameters and microstructural and mechanical investigation.
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Julsri, Weerapong, i Vitoon Uthaisangsuk. "Study of Effect of Varying Clearances on the Springback of Advanced High Strength Steel Sheets". Journal of Physics: Conference Series 2175, nr 1 (1.01.2022): 012008. http://dx.doi.org/10.1088/1742-6596/2175/1/012008.
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Abstract The springback of metal sheets shows a significant effect on the forming results of automotive structural parts. The components of new vehicles often have complex shapes, for which more precise forming procedures are required in order to achieve their desired geometries. Such springback occurrence is highly critical in the case of advanced high strength (AHS) steels. In this work, a V-shape stamping test was carried out for the AHS steel sheets grade 980 with an initial thickness of 1 mm. In parallel, the corresponding finite element (FE) simulations were conducted. Hereby, the Yoshida-Uemori (Y-U) kinematic hardening model was applied for describing the plastic deformation and elastic recovery of material. The parameters of the Y-U model were obtained from a tension-compression test and afterwards verified by using the 1-element model. The predicted bend angles of the formed samples fairly agreed with the experimentally measured results. Furthermore, the effect of defined die clearance at the corner of the formed sample on the magnitude of springback was numerically studied. It was found that the reduction of clearance of 10% led to obviously decreased shape deviations in the V-shape forming test.
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Jabłońska, Magdalena, i Rafał Michalik. "Studies on the Corrosion Properties of High-Mn Austenitic Steels". Solid State Phenomena 227 (styczeń 2015): 75–78. http://dx.doi.org/10.4028/www.scientific.net/ssp.227.75.
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Institute of Materials Science at Silesian University of Technology since 6 years conducts researches to learn about the new dedicated for automotive, railway and military industries. Some of these materials belong to the group of AHS steels, characterized by the twinning induced plasticity (TWIP) effect. It is a new type of steel possessing both a high strength and a great plastic elongation, and an ideal uniform work hardening behaviour. It is therefore a good candidate for deep drawing applications in the automobile and railway industries. In the paper the of the three grades of high-manganese steels of was studied in 3.5% NaCl solution and in an “acid rain” solution with pH=3.5 environments using polarization experiments. The results of corrosion tests and analysis of show that a higher polarisation resistance and lower values of corrosion current density are observed for all studied steels in 3.5% NaCl solution. Spontaneous passivation ability has been shown only for one grade of high-manganese steel in 3.5% NaCl.
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Jabłońska, Magdalena, Grzegorz Niewielski i Rudolf Kawalla. "High Manganese TWIP Steel - Technological Plasticity and Selected Properties". Solid State Phenomena 212 (grudzień 2013): 87–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.212.87.
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Over the last few years national as well as international research centres conducting research on the development of high-manganese steels. Some of these materials belong to the group of AHS steels, are characterized by the twinning induced plasticity (TWIP) effect which is a new type of steel possessing together with high strength a great plastic elongation, and an ideal uniform work hardening behavior. It is therefore a good candidate for deep drawing applications in the automobile and railway industry. The article presents the results of researches of TWIP-type austenitic steel in case of determination some of the more important parameters for continuous casting simulation process and the results of tests regarding the influence of strain parameters on sensitivity to plastic forming and deformation strengthening. It has been shown that the researched steel reaches a zero plasticity temperature at 1250°C. The deformation tests indicate its good workability of hot processing within the temperature range of 1100 ÷ 800°C. The relation between yield stress and strain during the hot deformation is typical for the presence of dynamic recrystallization processes. The tested steel has good formability and high mechanical properties, especially when being deformed at a high strain rate. Analysis of the substructure of researched steel was indicate presence of mechanical twinning.
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Ji, Jing, Weichen Wang, Liangqin Jiang, Hongguo Ren, Qingqin Wang, Wenyu Xuan i Yingchun Liu. "Bearing Capacity of UHPC-Filled High-Strength Elliptical Steel Tube Composite Columns with Encased High-Strength H-Shape Steel Subjected to Eccentrical Load". Buildings 12, nr 8 (19.08.2022): 1272. http://dx.doi.org/10.3390/buildings12081272.
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In order to investigate the bearing capacity of composite columns composed of ultra-high performance concrete, (UHPC)-filled high-strength elliptical steel tube with encased high-strength H-shape steel (HUCFESTCs) were subjected to eccentric load. Forty-four HUCFESTCs were designed with varying parameters: yield strength of the steel tube (fy), yield strength of the H-shape steel (fy1), concrete-cube compressive strength (fcu), steel tube thickness (t), eccentricity (e), slenderness ratio (λ), the section area of the H-shape steel (AHS), and long–short axis ratio (ψ). Based on a bilinear elastic–plastic constitutive model of steel that considered stress hardening and a nonlinear constitutive model of UHPC, 44 HUCFESTCs models were established by ABAQUS software. The influence of different parameters on the ultimate bearing capacity of the HUCFESTCs was analyzed. The whole process of HUCFESTCs under eccentric load was studied, and the typical failure modes of HUCFESTCs are described. The results show that the main failure mode of the HUCFESTCs subjected to eccentrical load is bulging outward of the steel tube, the buckling of the H-shape steel, and crushing of the concrete in the middle part of the column and the inner part of the H-shape steel. The stiffness of HUCFESTCs increases gradually with the increase in fy, t, and e. The ultimate eccentrical compression bearing capacity of HUCFESTCs improves gradually with increases in fy, t, fy1, AHS, ψ, and fcu, but it decreases gradually with increases in λ and e. By using statistical regression and introducing the reduction coefficient of eccentricity, the calculation formula for the eccentric bearing capacity of HUCFEST columns is developed, which can provide a basis for the application of HUCFESTCs in practical engineering.
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Panich, Sansot, i Vitoon Uthaisangsuk. "Effects of Anisotropic Yield Functions on Prediction of Forming Limit Diagram for AHS Steel". Key Engineering Materials 622-623 (wrzesień 2014): 257–64. http://dx.doi.org/10.4028/www.scientific.net/kem.622-623.257.
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In this study, experimental and numerical analyses of Forming Limit Diagram (FLD) for Advanced High Strength (AHS) steel grade 980 were performed. Forming limit curve was first determined by means of the Nakazima stretch-forming test. Then, analytical calculations of the FLD based on the Marciniak-Kuczynski (M-K) model were carried out. Different yield criteria, namely, Hill’48 (r-value and stress-based), Yld89 (r-value and stress-based) and Barlat2000 (Yld2000-2d) were investigated. The strain hardening law according to Swift was applied. To identify parameters of each model, uniaxial tension, balanced bi-axial bulge test and in-plane biaxial tension test were performed. As a result, predicted plastic flow stresses and plastic anisotropies of the AHS steel by various directions were evaluated. In addition, effects of the anisotropic yield functions, strain rate sensitivities, imperfection values and work hardening coefficient on the predicted FLD were studied and discussed. It was found that the FLD based on the Yld2000-2d yield criterion was in better agreement with the experimental curve. Accuracy of the FLD predictions based on the M-K theory, especially in the biaxial state of stress, significantly depended on the applied yield criteria, for which yield stresses and r-values of different loading directions were required.
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Chiyatan, T., P. Karin, N. Ohtake i V. Uthaisangsuk. "Finite element analysis of AHS steel under dynamic loading using a micromechanical modelling". Journal of Physics: Conference Series 1063 (lipiec 2018): 012109. http://dx.doi.org/10.1088/1742-6596/1063/1/012109.
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Sanrutsadakorn, Apichat, Winai Lawong i Weerapong Julsri. "Numerical Study of Predicting Forming Process Based on Different Hardening Models in Advanced High Strength Steel Sheets". Key Engineering Materials 951 (7.08.2023): 21–32. http://dx.doi.org/10.4028/p-g0pkwh.
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Sheet metal shaping for advanced high strength (AHS) steel sheets is commonly utilized in the manufacturing of automobile components. This helps to decrease the weight of new structures and increase the crashworthiness performance of these structures. The phenomenon known as springback deviation plays a significant role in creating such components via deformation and fracture. This study investigated the production of an S-rail from components made of steel grade 780 with a thickness of 1 millimeter by employing appropriate simulations using finite elements (FE) and generation. The materials were initially tested in order to collect the necessary parameter sets for the models being employed. The Barlat89 yield function, the Y-U kinematic hardening model, and a model combining the Y-U kinematic hardening model with the Barlat89 yield function were all used in the simulations. In addition, the forming limit curves (FLCs were utilized to assess the computed formabilities and served as the failure criteria. The deformation, springback effect, deviations, and twist springback of the components developed after the S-rail forming were subsequently studied, measured, and the findings compared. It was discovered that the proposed yield criteria and kinematic hardening models could accurately predict the formability of the material without causing any damage. The strain distributions acquired from the Y-U kinematic hardening indicated that the sidewall curl area was slightly larger than what was predicted by previous models. The model combining the Y-U kinematic hardening model with the Barlat89 yield function produced the most accurate predictions for overall springback effect, deviations, and twist springback of the AHS steel sheets.
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Julsri, Weerapong, Surasak Suranuntchai i Vitoon Uthaisangsuk. "Tension-Compression Tests for Springback Prediction of AHS Steel Using the Yoshida-Uemori Model". Key Engineering Materials 728 (styczeń 2017): 78–84. http://dx.doi.org/10.4028/www.scientific.net/kem.728.78.
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In sheet metal formingprocess of automotive parts, springback effect is crucial, in particular, foradvanced high strength (AHS) steels. Most structural components of new vehiclesshow very complex shapes that require multi–step forming procedures.Therefore, finite element (FE)simulation has been often used to describe plasticdeformation behavior and springback occurrence of formed metal sheets.Recently, the kinematic hardening Yoshida–Uemorimodel has showed great capability for predicting elastic recovery of material. In this work, the AHSsteel grade JSC780Y wasinvestigated, in which tension–compressiontests were carried out. From resulted cyclic stress–strainresponses, material parameters were identified using different fitting methods.Determined model parameters were firstly verified by using simulations of 1–elementmodel. The most appropriate parameter set was thenobtained. Finally, a Hat-Shape forming test was performed and springback waspredicted and compared with experimental results.
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Panich, Sansot, Frédéric Barlat, Vitoon Uthaisangsuk, Surasak Suranuntchai i Suwat Jirathearanat. "Forming Limit Curves and Forming Limit Stress Curves for Advanced High Strength Steels". Materials Science Forum 773-774 (listopad 2013): 109–14. http://dx.doi.org/10.4028/www.scientific.net/msf.773-774.109.
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Experimental and numerical investigations using Forming Limit Curve (FLC) and Forming Limit Stress Curve (FLSC) were carried out for two Advanced High Strength Steel (AHSS) grades DP780 and TRIP780. The forming limit curves were experimentally determined by means of Nakazima stretching test. Then, both FLC and FLSC were analytically calculated on the basis of the Marciniack-Kuczinsky (M-K) model. The yield criteria Barlat2000 (Yld2000-2d) were employed in combination with the Swift and modified Voce strain hardening laws to describe plastic flow behavior of the AHS steels. Hereby, influence of the constitutive models on the numerically determined FLCs and FLSCs were examined. Obviously, the forming limit curves predicted by the M-K model applying the Yld2000-2d yield criterion and Swift hardening law could fairly represent the experimental limit curves. The FLSCs resulted from the experimental data and theoretical model were also compared.
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Charoensuk, Kritchanan, i Viton Uthaisangsuk. "Determination of 3D Ductile Failure Criteria for Advanced High Strength Steel Sheet". Key Engineering Materials 658 (lipiec 2015): 53–58. http://dx.doi.org/10.4028/www.scientific.net/kem.658.53.
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In this work, 3D ductile fracture locus was determined for the advanced high strength (AHS) steel sheet grade DP780 using a hybrid approach between experiment and FE simulation. Tensile tests of different sample geometries were performed for the investigated dual phase steel, by which varying stress triaxiality (η) and lode angle (θ) values developed in the material during loading were introduced. During the tests, the direct current potential drop (DCPD) method and digital image correlation (DIC) technique were applied for identifying crack initiation on the micro-scale and fracture of the specimens due to local plastic deformation. Obtained force and displacement curves were correlated with the electric potential curves. Then, the moments of crack onset were determined for various states of stress. In parallel, the most critical areas of deformed samples before fracture were observed by the DIC method. Subsequently, FE simulations of the tensile tests were carried out and calculated local stresses and strains were gathered. The stress triaxialities, equivalent plastic strains and lode angles were evaluated for the corresponding detected areas. These threshold variables obtained from different specimens were plotted as the 3D failure locus for defining crack initiation and fracture occurrence in the DP steel.
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Panich, Sansot, Nopparat Seemuang i Taratip Chaimongkon. "Formability Analysis of Fukui Stretch-Drawing and Square Cup Drawing Using Strain and Stress Based Forming Limit Curves". Key Engineering Materials 751 (sierpień 2017): 167–72. http://dx.doi.org/10.4028/www.scientific.net/kem.751.167.
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In this work, the experimental and numerical analyses of Forming Limit Curve (FLC) and Forming Limit Stress Curve (FLSC) for Advanced High Strength Steel (AHSS) sheet, grade JAC780Y, are performed. Initially, the FLC is experimentally determined by means of the Nakazima Stretch forming test. Subsequently, the FLSC of investigated steel was plastically calculated using the experimental FLC data. Different yield criteria including Hill48, and Yld89, are applied to describe plastic flow behavior of the AHS steel and Swift hardening law is taken into account. Hereby, influences of the constitutive yield models on the numerically determined FLSCs are evaluated regarding to those results from the experimental data. The obtained stress based forming limits are affected significantly by the yield criteria. Finally, the experimental and numerical formability analyses of Fukui stretch-drawing and square cup drawing tests are studied through FLC and FLSCs. It is observed that all stress based curves can be used very well to describe material formability of the examined steel compared to the strain based FLC. The strain based FLC depend on forming history and strain paths change. In the other hand, the stress based FLC do not depend on these issue. In this study, it can be concluded that the FLSCs could predict failure more realistically and better than the strain based FLC.
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Mašek, Bohuslav, Ivan Vorel, Hana Jirková i Petr Kurka. "Combination of International High Pressure Forming and Q-P Process for Production of Hollow Products from Ahs Steel". Advanced Materials Research 1127 (październik 2015): 9–15. http://dx.doi.org/10.4028/www.scientific.net/amr.1127.9.
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All sectors of industry experience high demand for shaped products with as good mechanical properties as possible at low costs. Automotive industry, in addition, requires that the parts are of lightweight construction. Consequently, new types of materials and processes have to be combined to design new production chains capable to meet this demand. For instance, there are high-strength low-alloyed steels, whose final properties are attained by advanced heat treating techniques. One of such techniques is the Q&P process which can deliver excellent ultimate strengths exceeding 2000 MPa at a sufficient elongation level of 10 %. When combined with an unconventional forming method, it allows complex-shaped parts with outstanding mechanical properties to be made. One example of such combined procedure is the sequence of internal high pressure forming, hot stamping and Q&P processing. In the present study, thin-walled hollow stock was processed using such a combined procedure. After stepwise optimization of processing parameters, products with martensitic structure and a small amount of bainite were obtained. In all locations of the product which were tested, the ultimate strength exceeded 1950 MPa and elongation reached 15 %
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Franceschi, Mattia, Luca Pezzato, Alessio Giorgio Settimi, Claudio Gennari, Mirko Pigato, Marina Polyakova, Dmitry Konstantinov, Katya Brunelli i Manuele Dabalà. "Effect of Different Austempering Heat Treatments on Corrosion Properties of High Silicon Steel". Materials 14, nr 2 (8.01.2021): 288. http://dx.doi.org/10.3390/ma14020288.
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A novel high silicon austempered (AHS) steel has been studied in this work. The effect of different austenitizing temperatures, in full austenitic and biphasic regime, on the final microstructure was investigated. Specimens were austenitized at 780 °C, 830 °C, 850 °C and 900 °C for 30 min and held isothermally at 350 °C for 30 min. A second heat treatment route was performed which consisted of austenitizing at 900 °C for 30 min and austempering at 300 °C, 350 °C and 400 °C for 30 min. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) have been used to evaluate the microstructural evolution. These techniques revealed that the microstructures were composed of carbide-free bainite, ferrite, martensite and retained austenite (RA) in different volume fractions (Vγ). An aqueous borate buffer solution with 0.3 M H3BO3 and 0.075 M Na2B4O7∂10H2O (pH = 8.4) was used for corrosion tests in order to evaluate the influence of the different volume fractions of retained austenite on the corrosion properties of the specimens. The results showed that when increasing the austenitization temperatures, the volume fractions of retained austenite reached a maximum value at 850 °C, and decrease at higher temperatures. The corrosion properties were investigated after 30 min and 24 h immersion by means of potentiodynamic polarization (after 30 min) and electrochemical impedance spectroscopy (after both 30 min and 24 h) tests. The corrosion resistance of the samples increased with increases in the volume fraction of retained austenite due to lower amounts of residual stresses.
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Franceschi, Mattia, Luca Pezzato, Alessio Giorgio Settimi, Claudio Gennari, Mirko Pigato, Marina Polyakova, Dmitry Konstantinov, Katya Brunelli i Manuele Dabalà. "Effect of Different Austempering Heat Treatments on Corrosion Properties of High Silicon Steel". Materials 14, nr 2 (8.01.2021): 288. http://dx.doi.org/10.3390/ma14020288.
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A novel high silicon austempered (AHS) steel has been studied in this work. The effect of different austenitizing temperatures, in full austenitic and biphasic regime, on the final microstructure was investigated. Specimens were austenitized at 780 °C, 830 °C, 850 °C and 900 °C for 30 min and held isothermally at 350 °C for 30 min. A second heat treatment route was performed which consisted of austenitizing at 900 °C for 30 min and austempering at 300 °C, 350 °C and 400 °C for 30 min. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) have been used to evaluate the microstructural evolution. These techniques revealed that the microstructures were composed of carbide-free bainite, ferrite, martensite and retained austenite (RA) in different volume fractions (Vγ). An aqueous borate buffer solution with 0.3 M H3BO3 and 0.075 M Na2B4O7∂10H2O (pH = 8.4) was used for corrosion tests in order to evaluate the influence of the different volume fractions of retained austenite on the corrosion properties of the specimens. The results showed that when increasing the austenitization temperatures, the volume fractions of retained austenite reached a maximum value at 850 °C, and decrease at higher temperatures. The corrosion properties were investigated after 30 min and 24 h immersion by means of potentiodynamic polarization (after 30 min) and electrochemical impedance spectroscopy (after both 30 min and 24 h) tests. The corrosion resistance of the samples increased with increases in the volume fraction of retained austenite due to lower amounts of residual stresses.
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Lucas, Julien, i Antoine Fourgeaux. "Helical CT Scan Evolution of Periprosthetic Cysts of a Stainless Steel DLC Coated Total Ankle Arthroplasty at Four Years Apart and Survival at 13 Years". Foot & Ankle Orthopaedics 3, nr 3 (1.07.2018): 2473011418S0007. http://dx.doi.org/10.1177/2473011418s00078.
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Category: Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) is the alternative to tibio-talar fusion in the non-conservative operative treatment of osteoarthritis. It preserves joint range of motion and prevents adjacent joints while improving quality of life and relief. Long-term studies frequently show the presence of periprosthetic cysts, which is linked to an increased risk of revision, pain or lameness. In 2012, a stainless steel, DLC coated, TAA was subjected to a clinical review and a CT scan analysis. The main objective of this study was to analyze periprosthetic cysts evolution (numbers and volumes) on helical CT scans at 4 years apart of this same cohort of patients. The secondary objective was to present clinical results and survival curve of the implant. Methods: We retrospectively reviewed the cohort of 68 cases from 2012. The average follow-up was 13 ± 6 years. 42 CT analysis of the Periprosthetic cysts, were performed at the last follow-up and compared to the 2012 analysis. Cysts were classified in 3 groups (A: 0-200mm2, B: 200-400mm2, C:> 400 mm2) distributed over 7 areas. Numbers, locations and sizes were listed. The functional evaluation was performed in 2012 and at the last follow-up with the American Orthopedic Foot and Ankle Society Ankle and Hindfoot Score (AOFAS-AHS) and with the range of motion. TAR survival at 5 years were calculated for the 68 patients, and for the last 34 to avoid the learning curve effect. Two end points were defined: revision or removal of the implant for any reasons and revision or removal of the implant for aseptic loosening. TAR survival at 10 years was also analyzed thanks to the long follow-up. Results: Cysts size and prevalence were not significantly different at 4-year apart (p> 0.05). No type C cysts were revealed. The mean AOFAS-AHS was 77.6 ± 15.4 [38-98] in 2012 and stable at 75 ± 18.2 [16-97] at the last follow-up. Pre-operative ankle range of motion and at the last follow-up were not significantly different. The 5-year survival for the last 34 cases were 85.2% [73.2; 97.2] for any cause of revision and 90.7% [80.7; 100] for aseptic loosening. The 10-year survival for the last 34 cases were 77.1% [67.3; 87.4] for any cause of revision and 85.4% [73.4; 98.4] for aseptic loosening. Between 2012 and 2016, one case was revised for aseptic loosening of the talar component and two cases needed fusion. Conclusion: This study shows no significant increase of cysts volume or number at 4-year apart with a stainless steel, DLC coated TAA. The clinical results and 5-year survival are similar to those in the literature. The strength of this study is its mean follow-up greater than 13 years which allowed a 10-year survival and a long-term CT scan analysis. The implant design (spherical tibial component, dual curvature PE insert, trochlear-shaped talar component), its materials (DLC coated stainless steel) and its fixation (alumina coating) ensure long-term similar clinical results, with no break after 5-year survival, and stability of cysts prevalence and size.
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Stern, I. L., M. Wheatcroft i D. Y. Ku. "Higher-Strength Steels Specially Processed for High Heat Input Welding". Journal of Ship Production 1, nr 04 (1.11.1985): 222–37. http://dx.doi.org/10.5957/jsp.1985.1.4.222.
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ABS Grade EH36 steel plates, specially formulated and produced with advanced metallurgical techniques, are shown to have a significantly greater resistance to weld heat-affected zone (HAZ) degradation that conventional EH36 steel. Welds made in these steels with the electroslag welding process at high heat input rates retained adequate toughness in the heat-affected zone at --4°F (-20°C); similar welds in conventional EH36 steel plate exhibit excessive HAZ toughness loss. This effect was confirmed on the basis of small-scale Charpy V-notch and large-scale explosion bulge testing. In view of their superior resistance to HAZ degradation, the steels should also be useful for applications where HAZ degradation is of particular concern, such as for American Bureau of Shipping (ABS), U.S. Coast Guard, and International Maritime Organization (IMO) weld requirements for liquefied gas carriers.
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Boumerzoug, Zakaria, Lamia Baghdadi, François Brisset, Denis Solas i Thierry Baudin. "SOLID STATE DIFFUSION BONDING OF X70 STEEL TO DUPLEX STAINLESS STEEL". Acta Metallurgica Slovaca 28, nr 2 (22.06.2022): 106–12. http://dx.doi.org/10.36547/ams.28.2.1504.
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This paper deals with the solid state diffusion bonding of X70 steel to duplex stainless steel. Microstructure and mechanical properties of the welded dissimilar steels were investigated. Optical microscopy, Electron Backscatter Diffraction, energy dispersive spectrometry, Vickers hardness measurements, and X-Ray Diffraction were the main techniques of characterization. Microtructural variation was observed in the X70 steel side compared to duplex stainless steel. The diffusion coefficient of iron, chromium, and nickel across the interface X70 steel/duplex stainless steel was also measured. The diffusion coefficient of iron and chromium is higher than that of nickel. The Vickers microhardness profile across the bond joint showed an abrupt decrease in hardness from duplex stainless steel to X70 steel. In addition, a dynamic recrystallisation reaction was observed close to the interface in the X70 steel side.
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Fu, Yu Dong, i Qing Fen Li. "Grain Boundary Fracture Behavior and Segregation of P under Low Tensile Stresses in Steel 2.25Cr1Mo and 12Cr1MoV". Key Engineering Materials 577-578 (wrzesień 2013): 193–96. http://dx.doi.org/10.4028/www.scientific.net/kem.577-578.193.
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Experimental investigation about the grain boundary fracture behavior and segregation behavior of phosphorus under low tensile stresses in steel 2.25Cr1Mo and 12Cr1MoV was carried out in this paper. AES (Auger electron spectroscopy) experiments and dynamic analyses on the non-equilibrium grain-boundary segregation (NGS) of phosphorus and the SEM photos of grain boundary fracture in Auger specimens of both steels were obtained. The variation of phosphorus segregation level in grain boundary at different aging time was studied. Results show that the non-equilibrium segregation of phosphorus occurred at the grain boundaries in the two steels while subjected to a tensile stress of 30MPa and held at 500°C. The corresponding critical time was about 1 hour for steel 2.25Cr1Mo and 3.5hour for steel 12Cr1MoV respectively. SEM photos of grain boundary fracture in Auger specimens of the test steels show that the grain boundary fracture rate increased with increasing concentration of phosphorus, and that the fracture toughness of steel 12Cr1MoV is much lower than the one of steel 2.25Cr1Mo.
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Ouyang, Ye Xian, i Jing Liu. "High Temperature Brittleness of Non-Oriented Electrical Steel Containing Phosphrous". Advanced Materials Research 396-398 (listopad 2011): 350–55. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.350.
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High temperature brittleness of non-oriented electrical steel containing 0.14wt% phosphorus was investigated by mechanical testing, scanning electrical microscopy (SEM) and Auger electron spectroscopy (AES). The steels were annealed at 800~950°C with hold time of 2~30min under dry hydrogen/nitrogen mixture and wet mixture gas. The mechanical testing results indicated that elongation and bend-to-failure times of steel sheets annealed in wet gas was decreased with hold time extending, and dramatically dropped when it exceeded some value. The critical time of brittleness was become shorter with increase of annealing temperature. It was shown by AES that the phosphorus segregation at grain boundary induced by decarbonizing under wet gas led to inter-granular brittle fracture in the steel sheets.
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Pascu, Doru Romulus, Radu Alexandru Roşu, Iuliana Duma i Horia Daşcău. "Quality Assessment of Weldable Steel Mark P355NH from Decompression Chamber Construction for Diving". Applied Mechanics and Materials 217-219 (listopad 2012): 2381–87. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.2381.
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Non-alloyed P355NH steel according to EN 10028-3:2003 belongs to a group of fine-grained steels for pressure vessels being used in welded construction at decompression chamber for divers. Values of the chemical, structural and mechanical characteristics and steel toughness experimentally determined fit the analyzed steel in P355NH steel group according to EN 10028-3:2003. The toughness of the analyzed steel at the test temperature of -30°C is characterized by high values of fracture energy KV in longitudinal direction between 48 and 86 J and on transverse direction between 17 and 34J. Steel toughness at the test temperature of -30°C required by ABS standard (in Section 4/5.3 and Table 1) provides for breaking energy KV of min. 35J, with ductile fracture surfaces, value that is not respected at some lots of the three batches (A, B, C) of steel. Finally, based on the direct correlation established between HV10 hardness of the fine structure and the toughness it was made a selection of the lots of non-alloy steel P355NH which correspond to ABS norm for welded construction of the decompression chamber for divers
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Silva, R. C. L. De, i W. K. D. L. K. Walpita. "Optimization of Curcumin Method and Usage of Natural Curcumin in Determination of Boron in Steel". Asian Journal of Chemical Sciences 13, nr 3 (5.07.2023): 41–49. http://dx.doi.org/10.9734/ajocs/2023/v13i3243.
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Boron containing alloy steels are mainly used in constructional, automotive and many other applications. The presence of even trace amounts of boron affects greatly on the properties of steel such as hardness and machinability. Therefore, it is important to determine it accurately and precisely in the manufacture of these alloys. Due to the drawbacks of common advanced techniques such as Atomic Absorption Spectroscopy (AAS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), the universally accepted method for determination of boron in steel is the spectrophotometric method using curcumin as an auxiliary agent.
Although curcumin is the most sensitive spectrophotometric reagent for the above analysis, synthetic curcumin is relatively expensive and it tends to degrade rapidly once it is exposed to air. Furthermore this method is time consuming. Therefore, this study was carried out in order to improve and optimize the available spectroscopic method and to investigate the possibility of using natural curcumin extracted from turmeric in the above analysis.
The results of the study implied that natural curcumin extracted and purified from turmeric can be used as accurately and precisely as synthetic curcumin in the analysis of boron in steel. A boron-steel alloy sample found to be containing 0.26±0.01 percent of boron with synthetic curcumin gave a concentration of 0.25±0.00 percent of boron with natural curcumin, indicating no significant difference in the determination. A steel sample found to be containing 0.27±0.01 percent of boron with filter paper ashing step gave a concentration of 0.26±0.01 percent of boron without filter paper ashing step indicating no significant difference. Altering the refluxing step of current procedure significantly changes the concentration of boron indicating that the refluxing step cannot be optimized further.
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di Schino, Andrea, Laura Alleva i Mauro Guagnelli. "Microstructure Evolution during Quenching and Tempering of Martensite in a Medium C Steel". Materials Science Forum 715-716 (kwiecień 2012): 860–65. http://dx.doi.org/10.4028/www.scientific.net/msf.715-716.860.
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The microstructural evolution of a quenched medium-C steel during tempering was analyzed by means of Orientation Imaging Microscopy (OIM). The steel was heat treated in order to develop fully martensitic microstructures after quenching with a different prior austenite grain size (AGS). Main results can be summarized as below: A very poor effect of AGS on packet size was found in comparison to bainitic steels. A finer packet was measured at mid-thickness with respect to surface after the quenching process. This phenomenon was attributed to the effect of thermal strain path on phase transformation during quenching. The through-thickness microstructural gradient remains after tempering. High-angle boundary grains do not significantly grow after tempering; on the contrary, low-angle grain boundaries (cells) move, fully justifying the hardness evolution with tempering temperature.
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Prislupčák, Peter, Tibor Kvačkaj, Jana Bidulská, Stanislav Németh, Mária Demčáková, Roman Gburík i Vladimír Kundracík. "EFFECT OF RETAINED AUSTENITE ON PLASTIC CHARACTERISTICS OF DUAL PHASE STEELS". Acta Metallurgica Slovaca 28, nr 4 (13.12.2022): 212–18. http://dx.doi.org/10.36547/ams.28.4.1653.
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In terms of the current trend of research and development of new materials and optimization of current materials in the automotive industry, the greatest attention is paid to progressive high-strength dual-phase (DP) steels with increased stampability, which are designed for cold stamping for specific internal car body components of the current market. New grades of DP steels provide a combination of high strength and good formability and contribute to the weight savings of vehicle parts by 10 to 20 %, compared to current DP grades. Thanks to their top properties, DP steels with increased formability can absorb more crash energy using less steel. As a result, high-strength DP780GI and DP780GI-HF materials of first generation (hereinfater DP780GI-HF) were analyzed. The stampability improvement of DP steels was demonstrated by the experimentally determined Forming Limit Curves for both steels.
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Godbole, V. P., i J. Narayan. "Aluminum nitride buffer layer for diamond film growth". Journal of Materials Research 11, nr 7 (lipiec 1996): 1810–18. http://dx.doi.org/10.1557/jmr.1996.0228.
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The role of aluminum nitride (AlN) as a buffer layer on the nucleation and growth of diamond on silicon and steel substrates during hot filament chemical vapor deposition (HF-CVD) has been investigated systematically. The scanning Auger electron microscopy (AES) is employed to study chemistry and content of carbon on the surface and in subsurface regions of AlN as a function of HF-CVD parameters. It is found that AlN offers an excellent diffusion barrier for carbon over a wide range of temperature and hydrocarbon content of CVD gas environment, with simultaneous inhibition of graphitization. It also facilitates nucleation of diamond phase. The surface reactions between AlN and carbon are discussed in terms of hydrogen-assisted phase transformations. We have developed a two-step procedure to obtain a continuous diamond film on steel substrates. The characteristic features of AlN have been exploited to obtain adherent and graphite-free diamond deposits on various types of steels, including low carbon steel, tool steel, high speed steel, and bearing steel.
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Hossain Seikh, Asiful, Mahmoud S. Soliman, Abdulhakim AlMajid, Khaled Alhajeri i Waleed Alshalfan. "Austenite Grain Growth Kinetics in API X65 and X70 Line-Pipe Steels during Isothermal Heating". Advances in Materials Science and Engineering 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/246143.
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The aim of the present work is to investigate the microstructural behavior of austenite grain size (AGS) during the reheating process of two different API steel grades (X65 and X70). The steel samples were austenitized at 1150°C, 1200°C, and 1250°C for various holding times from 10 to 60 minutes and quenched in ice water. The samples were then annealed at 500°C for 24 hours to reveal the prior AGS using optical microscopy. It was noticed that the AGS in X65 grade is coarser than that of X70 grade. Additionally, the grain size increases with increasing the reheating temperature and time for both steels. The kinetics of grain growth was studied using the equationdn-d0n=Atexp-Q/RT, wheredis the measured grain size,dois the initial grain size,nis the grain size exponent,tis the heating time,Tis the heating temperature,Qis the activation energy,Ris the gas constant, andAis a constant. To characterize the grain growth process the values ofn,Q, andAwere determined. Good agreement is obtained between the prediction of the model and the experimental grain size values.
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Vatter, I. A., i J. M. Titchmarsh. "Segregation Measurements in Ferritic Steels Using AES and EDX". Microscopy and Microanalysis 3, S2 (sierpień 1997): 541–42. http://dx.doi.org/10.1017/s1431927600009594.
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A quantitative comparison has been made of intergranular segregation in four 9%-Cr ferritic steel alloys, S1-S4 doped, respectively, with 560, 300, 120 and 25ppm P, by both Auger Electron Spectroscopy (AES) and EDX in the analytical electron microscope (FEG-STEM). The strengths, weaknesses, relative accuracies and precision of the two methods were investigated in view of the different equipment, sample preparation, characteristic signals and unrelated assumptions in quantifying the results. No such investigation of ferritic steels has previously been reported, even though they are widely used in engineering components and can be susceptible to embrittlement. Comparative studies have been reported for austenitic alloys.The steels were solution-treated, tempered at 750°C and aged at 500°C for 100 hours. In-situ impact at low temperature in the VG MA500 AES apparatus caused mixed cleavage and intergranular fracture, the latter increasing with P content. Spectra from up to 80 individual intergranular facets were recorded from each alloy using a 5nA-10KeV beam from an LaB6 electron source under conditions which had been optimised by prior investigation.
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Lämsä, Janne, Anu Väisänen, Jouko Heikkala i Antti Järvenpää. "Correlation of Tensile Test Parameters and Bendability of High-Strength Steels". Key Engineering Materials 554-557 (czerwiec 2013): 12–20. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.12.
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The aim of the study was to investigate correlation between bendability and tensile properties of high-strength steels. Strength and elongation in tensile test have traditionally been basic values in evaluating bending properties. Advanced high-strength (AHS) steels often have tendency for strain localization, causing risk of fractures and impairing the shape of the bend. Practice has shown that tensile test results, indicating bendability well, are not sufficiently accurate when using AHS steels. Since tensile test is a fast, simple and cheap testing method, it would be beneficial to rework it to suit better for predicting of bendability. In this study, the usability of tensile test results to predict failures in bending AHS steels has been investigated. The most common failures and failure mechanisms in bending are also presented. Test materials used were 6 mm thick AHS wear-resistant, protection and structural steels with good and poor bending properties. Minimum bending radii were determined and then compared with ten-sile test results to estimate the correlation. Conventional tensile test results, fracture surfaces and necking through width and thickness were analyzed. Correlation coefficient for measured tension properties and minimum bending radius was calculated. Results showed that in tensile test, have the best correlation with minimum bending radius with necking through the thickness and actual strain in necking area.
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Kalaiselvi, Kathirvel, Ill-Min Chung, Seung-Hyun Kim i Mayakrishnan Prabakaran. "Corrosion resistance of mild steel in sulphuric acid solution by Coreopsis tinctoria extract: electrochemical and surface studies". Anti-Corrosion Methods and Materials 65, nr 4 (4.06.2018): 408–16. http://dx.doi.org/10.1108/acmm-12-2017-1866.
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Purpose The purpose of this paper is to investigate the inhibitive performance of Coreopsis tinctoria (C. tinctoria) plant extract for the corrosion of mild steel in 0.5 M H2SO4. Design/methodology/approach The inhibition efficiency was studied by weight loss, electrochemical measurements and the surface analysis was done by Raman, scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS) and atomic absorption spectroscopy (AAS) analysis. Findings Maximum inhibition efficiency of C. tinctoria in 0.5 M H2SO4 on mild steel is 80.62 per cent (500 ppm) at 303 ± 1K. The adsorption of the C. tinctoria on the mild steel surface in 0.5 M H2SO4 was found to obey Langmuir adsorption isotherm. Temperature studies were carried out and the significant parameters, such as change in enthalpy (ΔH°), change in entropy (ΔS°) and change in free energy (ΔG°ads) and heat of adsorption (Qads), were calculated. The productive layer formed on the mild steel surface in 0.5 M H2SO4 were confirmed by the Raman spectral analysis. Originality/value This paper provides information on the inhibitive properties of C. tinctoria plant extract which is found to be a good corrosion inhibitor for mild steel in 0.5 M H2SO4.
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Fernández-Jiménez, A., J. M. Miranda, J. A. González i A. Palomo. "Estabilidad del estado pasivo del acero en morteros de ceniza volante activada". Materiales de Construcción 60, nr 300 (26.04.2010): 51–65. http://dx.doi.org/10.3989/mc.2010.53909.
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Dong, Xin, Xiaobing Li, Weiwei Xing, Leilei Ding, Yingche Ma, Kui Liu i Nannan Zhang. "Effect of Trace Mg on Impact Toughness of 2.25Cr1Mo Steel Doped with 0.056% P at Medium Temperature Aging Process". Metals 11, nr 1 (23.12.2020): 10. http://dx.doi.org/10.3390/met11010010.
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In order to investigate the effect of Mg addition on the embrittlement of Cr-Mo steels, the 2.25Cr1Mo steel plates containing Mg, P contents were refined with vacuum induction furnace and rolled with double-stick reversible rolling mill. The impact toughness evolution and microstructural characteristics of these steels after aging at 580 °C for up to 5000 h were systematically investigated. The grain boundary segregation behaviors of P, S, and Mg before and after aging were analyzed with auger electron spectroscopy (AES), and the microstructure characteristics of the steels were detected with optical electron microscope (OM) and transmission electron microscope (TEM). The research results show Mg addition can improve the impact toughness of the 2.25Cr1Mo steel to a certain extent even with 0.056 wt.% P doping. It was clarified that Mg can segregate to grain boundary during the aging process, and its strong segregation tendency can reduce the grain boundary segregation of P to some degree. The effects of Mg on the impact toughness after subjecting to 580 °C ageing, including element segregation behaviors at grain boundary, ferrite formation, prior austenite grain characteristics, and carbides at grain boundary were also identified and discussed.
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Shalygina, L. V., i G. N. Popkova. "Determination of tantalum in alloy steels by atomic emission spectrometry with inductively coupled plasma". Industrial laboratory. Diagnostics of materials 89, nr 2(II) (2.03.2023): 65–69. http://dx.doi.org/10.26896/1028-6861-2023-89-2-ii-65-69.
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The capabilities of inductively coupled plasma atomic emission spectrometry (ICP-AES) for the determination of tantalum in alloy steels without separation of matrix components have been analyzed. The analytical lines of tantalum and the method of sample preparation are selected. The effect of acids present in the analyzed solution on the analytical signal of Та has been studied. Optimal conditions of measurements were determined by changing one of the operational plasma parameters at simultaneous stabilization of all other parameters. The influence of the components of alloy steels on the analytical signal of tantalum has been studied. The metrological characteristics of the technique were evaluated proceeding from the results of analysis of certified mixtures (CM). To assess the correctness of the results obtained we used certified mixtures and standard addition technique. A method for measuring the mass fraction of tantalum in alloy steel samples by ICP-AES in the content range from 0. 01 % to 0. 05 % has been thus developed.
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Lee, Seok Jae, i Young Kook Lee. "Effect of Austenite Grain Size on Martensitic Transformation of a Low Alloy Steel". Materials Science Forum 475-479 (styczeń 2005): 3169–72. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.3169.
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There are many empirical equations for predicting martensite start temperature (Ms) and the kinetics models of martensitic transformation of plain carbon and low alloy steels. The Ms temperature equations are only dependent upon the chemistry, while the martensite transformation kinetics models are based on the degree of undercooling below Ms temperature. However, the prior austenite grain size (AGS) is also expected to influence both Ms temperature and martensite transformation kinetics as it does in diffusive transformations. In this study, herefore, both Ms temperature and martensite transformation kinetics of a low alloy steel with different austenite grain sizes were investigated using a dilatometer. The new Ms equation and martensite transformation kinetics model including the AGS effect are proposed.
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Polyxeni, Vourna, Papadopoulos Nikolaos D, Stefanakis Nikos, Xafakis Sotirios i Hristoforou Evangelos. "Temperature effects on grain growth phenomena and magnetic properties of silicon steels used in marine applications". Annals of Marine Science 7, nr 1 (21.06.2023): 040–44. http://dx.doi.org/10.17352/ams.000037.
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The present paper investigates the stages of the microstructure and texture evolution in non-oriented electrical silicon steels by means of magnetic measurements and metallographic analysis. The goal of this work was to study temperature effects and their influence on grain growth processes in non-oriented electrical steels while being subjected to different annealing conditions and to clarify the mechanism of grain boundary motion during annealing. It is important to study the development of texture and grain size in electrical steel samples along the entire production line chain (hot rolling, cold rolling, and final annealing), as both are affected by each processing stage. The lack of magnetic data dependent on the operating temperature of non-oriented electrical steels makes it impossible to accurately design high-power motors (e.g., propulsion systems in ships) or generators that are to operate at high temperatures. The correlation of magnetic properties with the microstructure of electrical steels can yield important information about their suitability for various substrates and marine applications. In addition, it can potentially non-destructively define both the annealing stage and the preferred crystallographic growth pattern in single-phase ferritic steels, which affect the performance and longevity of the electromagnetic devices in which these are used.
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Yun, Yeon Jun, Kyung Lim Ahn, Won Gyun Lim i Hyun Do Yun. "Effects of Steel Fiber Volume Fraction on Compressive and Flexural Behaviors of Alkali-Activated Slag (AAS) Concrete". Applied Mechanics and Materials 525 (luty 2014): 469–72. http://dx.doi.org/10.4028/www.scientific.net/amm.525.469.
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This paper describes the experimental results on compressive and flexural behavior of alkali-activated slag (AAS) concrete reinforced with hooked end steel fiber. Two different fiber volume fractions of 0.5 and 1.0% were used for AAS concrete and Ordinary Portland cement (OPC) concretes were also mixed for comparison. Test results indicated that compressive and flexural performance of AAS concretes with water-to-binder (W/B) ratio of 0.55 are equivalent to those of OPC concrete. The addition of steel fiber to AAS concrete improves more compressive and flexural performance than those of steel fiber reinforced concrete.
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Hejjaj, Chaymae, Ahmed Ait Aghzzaf, Nico Scharnagl, Mohammed Makha, Mouad Dahbi, Mikhail L. Zheludkevich, Rachid Hakkou i Christian B. Fischer. "Effect of 6-Aminohexanoic Acid Released from Its Aluminum Tri-Polyphosphate Intercalate (ATP-6-AHA) on the Corrosion Protection Mechanism of Steel in 3.5% Sodium Chloride Solution". Corrosion and Materials Degradation 2, nr 4 (12.11.2021): 666–77. http://dx.doi.org/10.3390/cmd2040036.
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A new corrosion inhibitor called ATP-6-AHA was elaborated, and its inhibition action on S235 low carbon steel in 3.5% sodium chloride (NaCl) was investigated using gravimetry, potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS). The release of ecofriendly 6-aminohexanoic acid (6-AHA) from its established aluminum tri-polyphosphate intercalate (ATP-6-AHA) is investigated using electrochemical and surface characterization techniques such as X-ray diffraction (XRD) and X-ray fluorescence (XRF). The results revealed that ATP-6-AHA is a good inhibitor, with an inhibition efficiency of approximately 70%. The efficiency is related to the passivation of a steel surface by a phosphate protective layer due to the synergistic effect of 6-AHA, as confirmed by a steel surface analysis conducted using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). This study suggests that the intercalation of 6-AHA as a sustainable organic molecule within the interlayer spaces of aluminum tri-polyphosphate can well serve as a good flaky inhibitor for protecting S235 low-carbon steel from corrosion in 3.5% NaCl.
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Stornelli, Giulia, Matteo Gaggiotti, Daniele Mirabile Gattia, Rolf Schmidt, Mirko Sgambetterra, Anastasiya Tselikova, Guido Zucca i Andrea Di Schino. "VANADIUM ALLOYING IN S355 STRUCTURAL STEEL: EFFECT ON RESIDUAL AUSTENITE FORMATION IN WELDED JOINTS HEAT AFFECTED ZONE". Acta Metallurgica Slovaca 28, nr 3 (24.09.2022): 127–32. http://dx.doi.org/10.36547/ams.28.3.1535.
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The inter-critical heat affected zone (ICHAZ) appears to be one of the most brittle sections in the welding of high-strength micro-alloy steels (HSLA). Following multiple heating cycles in the temperature range between Ac1 and Ac3, the ICHAZ undergoes a strong loss of toughness and fatigue resistance, mainly caused by the formation of martensite-austenite constituent (MA). The presence of micro-alloying elements in HSLA steels induces variations in the formation of some microstructural constituents, more or less beneficial, which allow to improve the mechanical performance of a welded joint. The behavior in the inter-critical region of a S355 grade steel with 0.1wt% V addition is reported in this paper. Five double-pass welding thermal cycles were simulated using a dilatometer, with the maximum temperature of the secondary peak in the inter-critical area, in the range between 720 ° C and 790 ° C. The residual austenite dependence on inter-critical temperature is analyzed and related to the hardness behavior.
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Yonezu, Akio, Hideo Cho i Mikio Takemoto. "Detection of Stress Corrosion Cracking of Type 304 Stainless Steel Using Acoustic Emission and Corrosion Potential Fluctuation". Advanced Materials Research 13-14 (luty 2006): 243–50. http://dx.doi.org/10.4028/www.scientific.net/amr.13-14.243.
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This paper discusses the mechanism of chloride SCC of sensitized and non-sensitized Type-304 stainless steel based on the data obtained by simultaneous monitoring of AE and corrosion potential fluctuation (CPF). The steel produced transgranular SCC via corrosion pits filled with corrosion product (chromium oxy-hydroxides) in 35 mass % MgCl2 solution. Both the pitting corrosion and transgranular SCC did not produce primary AEs due to anodic dissolution, while they generated rapid drop (RD) type CPF. We, however, detected the secondary AEs from hydrogen gas evolution and fracture of corrosion products. Hydrogen gas was found to produce AE with single frequency component, while the fracture of corrosion products produced AEs with broad frequency components. The sensitized steel produced primary AEs due to the falling-off of grains as well as the secondary AEs. Microscopic progression of SCC was consistently interpreted by the timing and time-lag of AEs and CPFs.
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Yan, Chang, Xu Ding Song i Shuo Feng. "Aluminum Foam Sandwich with Different Face-Sheet Materials under Three-Point Bending". Applied Mechanics and Materials 872 (październik 2017): 25–29. http://dx.doi.org/10.4028/www.scientific.net/amm.872.25.
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Aluminum foam sandwich structure is a new type of composite material with excellent mechanical and functional properties. As it is known that properties of aluminum foam sandwiches (AFS) vary if the foam core is sandwiched between different face sheets. To study the effects of face-sheet materials on the mechanical properties of AFS and enable a better understanding of the usage of such AFS structures under flexural load, AFS sandwiched by 6061-aluminum alloy face-sheets and 304 stainless steel face-sheets were fabricated and investigated under three-point bending by using WDW-T100 electronic universal tensile testing machine. Results showed that 6061-aluminum alloy reinforced AFS had the same peak load value with 304-stainless steel reinforced one almost so long as the thicknesses of the face-sheet material were the same and the foam core densities were the same too, but the energy absorption ability of 304-stainless steel reinforced AFS was much higher than that of 6061-aluminum alloy reinforced. However, the integrality of the 6061-sandwiched AFS was better than 304-sandwiched AFS. Deformation modes of the two types of AFS were also discussed in the present study.
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Vorel, Ivan, Hana Jirková, Bohuslav Mašek i Petr Kurka. "Production of shaped semi-products from AHS steels by internal pressure". Materiali in tehnologije 49, nr 5 (25.09.2015): 739–44. http://dx.doi.org/10.17222/mit.2014.218.
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Saketi, Sara, Ulf Bexell, Jonas Östby i Mikael Olsson. "Wear Behaviour of Two Different Cemented Carbide Grades in Turning 316 L Stainless Steel". Materials Science Forum 941 (grudzień 2018): 2367–72. http://dx.doi.org/10.4028/www.scientific.net/msf.941.2367.
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Cemented carbides are the most common cutting tools for machining various grades of steels. In this study, wear behavior of two different cemented carbide grades with roughly the same fraction of binder phase and carbide phase but different grain size, in turning austenitic stainless steel is investigated. Wear tests were carried out against 316L stainless steel at 180 and 250 m/min cutting speeds.The worn surface of cutting tool is characterized using high resolution scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Auger electron spectroscopy (AES) and 3D optical profiler.The wear of cemented carbide in turning stainless steel is controlled by both chemical and mechanical wear. Plastic deformation, grain fracture and chemical wear is observed on flank and rake face of the cutting insert. In the case of fine-grained, the WC grains has higher surface contact with the adhered material which promotes higher chemical reaction and degradation of WC grains, so chemical wear resistance of the composites is larger when WC grains are larger. The hardness of cemented carbide increase linearly by decreasing grain size, therefore mechanical wear resistance of the composites is larger when WC grains are smaller.
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Kang, Dae Hyun, Hye Ran Kim i Hyun Do Yun. "Effect of Steel Fiber Volume Fraction and Curing Conditions on the Compressive Behavior of Alkali-Activated Slag Concrete". Applied Mechanics and Materials 525 (luty 2014): 491–94. http://dx.doi.org/10.4028/www.scientific.net/amm.525.491.
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In this paper, an experimental investigation was carried out to examine the influence of hooked end steel fiber volume fraction and curing conditions on the compressive performance of concrete produced by using ordinary portland cement (OPC) and alkali-activated slag (AAS). Three different volume fractions of 0.5%, 1.0% and 1.5% were used in OPC and AAS concrete mixtures. Cylindrical specimens with 100 x 200mm were tested for compressive behavior of both concretes at 3, 7 and 28 days of curing age. Test results showed that curing conditions had a significant effect on compressive properties in the hardened OPC and AAS concretes. The addition of steel fibers generated a decrease in compressive strength of OPC while an increase in the compressive strength of AAS concrete was shown with adding steel fiber.
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Makarov, V. A., i T. K. Savosteenko. "Determination of phosphorus mass fraction in steels of plasma atomic emission spectrometry". Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), nr 1 (26.03.2021): 86–90. http://dx.doi.org/10.21122/1683-6065-2021-1-86-90.
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A method for measuring the mass fraction of phosphorus in steels by atomic emission spectrometry with the inductively coupled plasma (AES-ICP) has been developed. Possibilities of atomic emission spectrometers of iCAP series for determination of phosphorus in steels allowing to reduce considerably duration of the analysis and to increase its profitability in comparison with chemical methods of the analysis are investigated. A method of decomposition of steel for the complete transfer of phosphorus into solution is proposed. The possibility of software spectrometers “iTeva” in the analysis by the method of relative concentrations. Calibration of the spectrometer was carried out on aqueous solutions with a known concentration of phosphorus using the method of relative concentrations. For the preparation of calibration solutions, chemically pure salt was used. The analytical line free from spectral overlays is selected. A good correlation of the calibration graph is obtained. The correctness of the determination is confirmed by the analysis of standard samples and comparison with the results of the determination in accordance with the chemical method. The developed technique is used in determining the mass fraction of phosphorus in steels. Validation of the methodology was carried out. iCAP spectrometers can be used to determine the mass fraction of phosphorus in steels.
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Song, Wen Zhong, Qi Fang, Hui Ping Ren, Zi Li Jin i Hui Chang. "Effect of Rare Earth (RE) La on Solid Solution of Second Phase Particle and Austenite Grain Growth in Steel Containing High Niobium". Advanced Materials Research 189-193 (luty 2011): 2869–74. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.2869.
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The solid solution of the second phase particle and austenite grain growth behavior of the high niobium-containing RE steel was studied by mathematical calculation and extraction replica technique. The purpose of the study was to investigate the effects of Rare Earth La on austenite grain growth and propose an empirical equation for predicting the austenite grain size of RE steel. Austenite grain grows in an exponential law with the increase of heating temperature, while approximately in a parabolic law with the increase of holding time. Results show that the RE steel has good anti-coarsening ability at elevated temperatures. When soaking temperature is lower than 1250°C , AGS and growth rate are small for high niobium steel, but soaking temperature is lower than 1220°C , AGS and growth rate are small for RE steel. RE La can promote solid solution of second-phase particles Nb(C, N), the solution temperature decrease 30°C than high niobium steel.
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FERRO, PAOLO, Alberto Fabrizi, Franco Bonollo i Jan-Olof Nilsson. "CHARACTERIZATION OF CHROMIUM NITRIDE PRECIPITATION IN THE HEAT AFFECTED ZONE OF THE SUPERDUPLEX STAINLESS STEEL UNS S32750: AN EXPERIMENTAL AND NUMERICAL ANALYSIS". Acta Metallurgica Slovaca 27, nr 2 (1.06.2021): 57–62. http://dx.doi.org/10.36547/ams.27.2.902.
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It is well known that pitting corrosion resistance of duplex and superduplex stainless steels strongly depends on
microstructural characteristics such as ferrite/austenite proportion, presence of intermetallic phases and elemental partitioning between the austenite and ferrite phases. In particular, during the welding operation, very fine chromium nitrides may precipitate
within ferrite grains of the heat affected zone drastically reducing the corrosion resistance of welded joints of duplex and super duplex stainless steels. However, due to their small size and low distribution, analyzing the chemical composition and crystallography of chromium nitrides is quite difficult and only a restricted number of advanced techniques of investigation may discriminate their signal from the surrounding matrix. This work is aimed at supporting the microstructural characterization of a welded joint of a superduplex stainless steel by means of a field-emission gun scanning electron microscope. Sub-micron chromium nitride precipitates, identified within the ferritic grains of the heat affected zone, are recognized to be the main reason for the reduced pitting corrosion resistance of the analyzed welded joints. The results are supported by a multi-pass welding process numerical simulation aimed at estimating the cooling rates promoting chromium nitride precipitation in the heat affected zone.
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Khun, Nay Win, i Erjia Liu. "Thermal, mechanical and tribological properties of polycarbonate/acrylonitrile-butadiene-styrene blends". Journal of Polymer Engineering 33, nr 6 (1.09.2013): 535–43. http://dx.doi.org/10.1515/polyeng-2013-0039.
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Abstract Polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) were blended by varying ABS content. The thermal, mechanical and tribological properties of the PC/ABS blends were systematically characterized. Increasing ABS content in the PC/ABS blends decreased thermal stability of the blends, as a result of the lower thermal stability of the ABS than that of the PC. Although the tensile strength of the PC/ABS blends apparently decreased with increased ABS content, the PC/ABS blend with 10 wt% of ABS had the highest tensile strength, because of improved processability of the blend. The friction and wear of the ABS measured against a steel ball of 6 mm in diameter were higher than those of the PC. As a result, a higher ABS content in the PC/ABS blends resulted in higher friction and wear of the blends. The scratch results showed that scratching with a 5 mm steel ball generated a scratch with a shorter length and lower depth on the PC than on the ABS, which indicated better scratch resistance of the PC. Therefore, the PC/ABS blend with 50 wt% of PC had better scratch resistance than the ABS, due to the influence of the PC embedded in the blend.