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Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Acier bas carbone, Low carbon steel, Acero bajo carbono, Kohlenstoffarmer Stahl, Acier non allié, Carbon steel, Acero no aliado, Unlegierter Stahl, Ductilité, Ductility, Ductilidad, Verformungsfaehigkeit, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Durcissement précipitation, Precipitation hardening, Endurecimiento precipitación, Ausscheidungshaerten, Ecrouissage, Work hardening, Endurecimiento en frío, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Zugeigenschaft, Précipitation, Precipitation, Precipitación, Ausscheidung, ductility, interphase precipitation, low carbon steel, precipitation strengthening, and work hardening

Tensile behavior and structure-property relationship of ferritic steels with nano-sized carbide dispersion were invesigated using Ti-added steel and Ti,Mo-added low carbon steels. By austenitizing followed by isothermal heat treatment at 700°C, polygonal ferrites containing very fine carbides of TiC and (Ti,Mo)C were obtained in the Ti-added and the Ti,Mo-added steels, respectively. The size of such carbides was finer in the Ti,Mo-added steel than in the Ti-added steel at the same isothermal holding. The results of tensile tests for these samples showed that the strength is higher as the carbide size is smaller. The structure-based strength calculation led to a good agreement with the experiments, when it was assumed that the Ashby-Orowan mechanism is dominant for precipitation strengthening of nano-sized alloy carbides. It was also suggested that a relatively large tensile ductility is related to enhanced recovery during the tensile deformation, accompanied with promotion of secondary slips or cross slips in a finer scale due to the nano-sized particles.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Formage, Forming, Laminage, Rolling, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Acier non allié, Carbon steel, Acero no aliado, Unlegierter Stahl, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Dislocation, Dislocación, Versetzung, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Ecrouissage, Work hardening, Endurecimiento en frío, Formage, Forming, Conformado, Umformen, Laminage à froid, Cold rolling, Laminado en frío, Kaltwalzen, Microstructure, Microestructura, Mikrogefuege, Propriété mécanique, Mechanical properties, Propiedad mecánica, Tôle laminée à froid, Cold rolled sheet, Chapa laminada en frío, Kaltgewalztes Blech, X-ray diffraction, cold-rolling, dislocation, mechanical property, and work-hardening

Line profile analyses of cold-rolled carbon steels were conducted to evaluate microstructural features such as dislocation density, crystallite size, and M values. After the samples were subjected to 40% cold-rolling, dislocation density increased from 7 × 1013 m-2 to 2 × 1015 m-2 and crystallite size decreased from 155 nm to 35 nm. The component ratio of screw and edge dislocations was approximately 1:1, as determined from the evaluation of the q values. The M value that indicated interaction of dislocations substantially decreased during the initial stage of cold-rolling, which means interaction of dislocations becomes strong. Proof stress, hardness, and tensile strength were increased by the cold-rolling process. Furthermore, the ratios between proof stress and hardness were initially 2 and increased to approximately 3. The correlation between the microstructures and the mechanical properties was demonstrated according to the Bailey-Hirsch relationship between flow shear stress and dislocation density. Variations in the proof stress and hardness as a function of the square root of dislocation density indicated that the work-hardening of the material is affected by not only the total amount of dislocations but also other factors, such as crystallite size and arrangement of dislocations.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements thermiques, Heat treatment, Traitements thermochimiques et traitements par diffusion, Thermochemical treatment and diffusion treatment, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Frottement. Usure, Contact of materials. Friction. Wear, Propriété mécanique, Mechanical properties, Propiedad mecánica, Traitement thermochimique, Thermochemical treatment, Tratamiento termoquímico, Thermochemische Behandlung, Acier austénito ferritique, Austenitic ferritic steel, Acero ferrítico austenítico, Austenitisch ferritischer Stahl, Acier double phase, Dual phase steel, Acero doble fase, Dualphasenstahl, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Diamant synthétique, Synthetic diamond, Diamante sintético, Dépôt chimique phase vapeur, Chemical vapor deposition, Depósito químico fase vapor, Chemisches Aufdampfen, Nitruration, Nitriding, Nitruración, Nitrieren, Oxydation, Oxidation, Oxidación, Oxynitruration, Oxynitriding, Oxinitruratión, Plasma, Structure diamant, Diamond structure, Estructura diamante, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tribologie, Tribology, Tribología, Usure, Wear, Desgaste, Verschleiss, DC-pulsed plasma CVD, DLC/oxynitriding duplex treatment, H13 alloy steel, and wear

In this study, diamond-like carbon (DLC) films were prepared by DC-pulsed plasma CVD after the oxynitride treatment of AISI H13 tool steel. In order to investigate the tribological properties of DLC films, a Raman spectroscopy analysis, wear test, adhesion and roughness tests were performed. The main parameters of the DC-pulsed plasma CVD process includes various pretreatment times of argon plasma (15, 30, 45 and 60 min). Experimental results showed that an oxynitride layer and the DLC films could be completely obtained after DLC/oxynitriding duplex treatment. The duplex coating layers had optimal adhesion (critical load reached to 10.65 N) and wear properties after DC-pulsed plasma was CVD treated via a low pulse voltage (―1.5 kV), pretreatment times of the argon plasma were 15 min and the substrate temperature was kept at 40°C. Meanwhile, the optimal DLC/oxynitriding duplex treated specimens possessed the lowest wear volume (2.25 × 10-3 mm3) and a lower friction coefficient (0.06).

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements thermiques, Heat treatment, Traitements thermochimiques et traitements par diffusion, Thermochemical treatment and diffusion treatment, Acier austénitique, Austenitic steel, Acero austenítico, Austenitischer Stahl, Acier inoxydable austénitique, Austenitic stainless steel, Acero inoxidable austenítico, Austenitischer nichtrostender Stahl, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Nitruration, Nitriding, Nitruración, Nitrieren, Plasma, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Traitement thermochimique, Thermochemical treatment, Tratamiento termoquímico, Thermochemische Behandlung, S-phase, active screen plasma nitriding, cathodic cage, open area ratio, stainless steel, and surface engineering

Austenitic stainless steel SUS 316L was nitrided by active screen plasma nitriding (ASPN) using screens with various open areas to investigate the effect of the screen's open area ratio on the nitriding response. The sample was placed on the sample stage in a floating potential and isolated from the cathodic screen and anode. The screen, which was SUS 316L expanded metal mesh with 38%, 48%, or 63% open area ratio, was mounted on the cathodic stage around the sample stage. Nitriding was performed in a nitrogen-hydrogen atmosphere with 25% N2 + 75% H2 for 18 ks at 693 K under 600 Pa by the ASPN process. After nitriding, the nitrided microstructure was examined using a scanning electron microscope and an electron probe microanalyzer. The phase structures on the nitrided surface were determined by X-ray diffraction. In addition, the surface hardness and cross section of the nitrided samples were measured by the use of a Vickers microhardness tester. The thickness of the nitrided layer of the S-phase decreased with increasing open area ratio of the screen.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Etat surface, Surface conditions, Estado superficie, Oberflaechenzustand, Acier galvanisé, Galvanized steel, Acero galvanizado, Additif, Additive, Aditivo, Zusatzstoff, Composé organique, Organic compounds, Compuesto orgánico, Organische Verbindung, Croissance, Growth, Crecimiento, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Epitaxie, Epitaxy, Epitaxia, Légèreté, Lightness, Ligereza, Morphologie, Morphology, Morfología, Orientation cristalline, Crystal orientation, Orientación cristalina, Kristallorientierung, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Rugosité, Roughness, Rugosidad, Rauhigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Tôle, Sheet metal, Chapa, Blech, Zn, crystal orientation, electrodeposition, epitaxial growth, lightness, morphology, organic additive, overpotential, preadsorption, and surface roughness

Zn electrodeposition was performed galvanostatically on steel sheets at 1 500 A/m2 in an agitated sulfate solution at 40°C to investigate the effect of preadsorption of organic additives on the lightness and morphology of Zn. The organic additives employed were classified into two types: 1) polyethylene glycol (PEG), gelatin, and stearyl dimethylbenzyl ammonium chloride (SDBAC) (Type I), which exhibit a polarization effect for Zn deposition; and 2) saccharin and sodium lauryl sulfate (Type II), which exhibit no polarization effect for Zn deposition. The platelet crystals of deposited Zn were reduced in size with preadsorption of all the organic additives considered. The observed decrease in the size of Zn platelet crystals with preadsorption is attributed to both an increase in the overpotential for Zn deposition and a decrease in the epitaxial growth of Zn on steel substrates. The preferred orientation of the {0001} Zn basal plane significantly decreased because of an increase in Zn deposition overpotential owing to preadsorption of PEG and gelatin, and the orientation slightly decreased with saccharin and sodium lauryl sulfate in spite of the absence of a polarization effect on Zn deposition. The surface roughness of deposited Zn decreased with preadsorption of organic additives with the exception of SDBAC. This is due to a decrease in the size of Zn platelet crystals. The lightness of deposited Zn was increased by preadsorption of organic additives with the exception of SDBAC. Because Zn deposited nonuniformly with preadsorption of SDBAC, the surface roughness of Zn increased and the lightness decreased.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Corrosion, Action des agents de corrosion, Corrosion environments, Protection contre la corrosion, Corrosion prevention, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Acier haute résistance, High strength steel, Acero alta resistencia, Hochfester Stahl, Corrosion, Corrosión, Korrosion, Epoxyde résine, Epoxy resin, Epóxido resina, Epoxidharz, Impédance, Impedance, Impedancia, Microscopie électronique transmission, Transmission electron microscopy, Microscopía electrónica transmisión, Transmissionselektronenmikroskopie, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Zugeigenschaft, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Résistance mécanique, Strength, Resistencia mecánica, Festigkeit, Résistance traction, Tensile strength, Resistencia tracción, Zugfestigkeit, EIS, FIB-TEM, HT steel, SECM, corrosion, and epoxy coatings

The corrosion protection performance of epoxy coated High Tensile Strength (HT) steel was evaluated by using Electrochemical Impedance Spectroscopy (EIS) and Scanning Electrochemical Microscope (SECM) analysis. EIS was performed on coated HT steel with a scratch in a 0.1 M NaCl solution after a wet/dry cyclic corrosion test. The charge transfer resistance (Rct) and film resistance (Rf) of coated HT steel displayed a higher value than coated carbon steel. SECM was conducted to estimate the corrosion performance of the epoxy coated HT steel immersed in a 0.1 M NaCl solution. It was measured that dissolution of Fe2+ was suppressed at the scratch on the coated HT steel due to the higher resistance for anodic dissolution of the substrate. SEM/EDX analysis showed that Cr and Mo were enriched in corrosion products at a scratched area of the coated steel after corrosion testing. FIB-TEM analysis confirmed the presence of the nanoscale oxide layers containing Cr, Ni and Mo in the rust of the steel, which had a beneficial effect on the corrosion resistance of coated steel by forming protective corrosion products in the wet/dry cyclic test.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Chlorure, Chlorides, Cloruro, Chlorid, Coloration, Coloración, Faerben, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Matériau composite, Composite material, Material compuesto, Verbundwerkstoff, Nickel, Niquel, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zingage électrolytique, Zinc plating, Zincato electrolítico, Galvanisches Verzinken, Zn-Ni composite, chloride solution, chromaticity, color, deposited film, electrodeposition, index of refraction, and interference of light

Zn-Ni composite films were electrodeposited under coulostatic (515-5145 C.m-2) and galvanostatic (5 A·m-2) conditions onto brass plates with a Ni precoating in an unagitated chloride solution at 23°C to investigate the color and structure of the deposited films. The chromaticity of the deposited Zn-Ni composite films changed in a clockwise direction in each quadrant of the a*b* diagram of the L*a*b* color space with increasing amount of charge. The deposited films contained S, Zn, and Ni, and their content decreased in the order of S > Zn > Ni. X-ray photoelectron spectroscopy revealed that the deposited films were primarily composed of ZnS, ZnO, and Ni and contained small amounts of Zn(OH)2 and Zn. The color of the deposited films is attributed to interference of light, and the index of refraction of the deposited films composed of ZnS, ZnO, and Ni is assumed to be large. When Ni was excluded from the electrolytic solution, ZnS did not codeposit and the amount of Zn deposited in the metallic state increased. This result suggests that the Ni deposition induces the codeposition of ZnS.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Propriété mécanique, Mechanical properties, Propiedad mecánica, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Transformation phase, Phase transformation, Transformación fase, Phasenumwandlung, Acier, Steel, Acero, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Ecrouissage, Work hardening, Endurecimiento en frío, Effet Bauschinger, Bauschinger effect, Efecto Bauschinger, Bauschinger Effekt, Essai flexion, Bending test, Ensayo flexion, Plasticité, Plasticity, Plasticidad, Plastizitaet, Transformation martensitique, Martensitic transformation, Transformación martensítica, Martensitische Umwandlung, back stresses, load transfer, residual stresses, and transformation induced plasticity

Martensite formed in TRIP steels causes large work hardening. The expectation that this is due to the back stresses induced into the ferrite by the hard martensite was examined by the Bauschinger effect after room temperature tensile straining of a TRIP steel into which the martensite had been introduced by prior straining at -50°C. Bending tests were employed to detect the Bauschinger effect. The tests showed that the compressive flow stress became much smaller than the tensile flow stress and confirmed the expectation.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Corrosion, Action des agents de corrosion, Corrosion environments, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Acier peint, Painted steel, Acero pintado, Farbueberzogener Stahl, Corrosion, Corrosión, Korrosion, Peinture, Paint, Pintura, Anstrich, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, 3D-elemental mapping, XRF, confocal micro-XRF, depth analysis, polycapillary x-ray lens, and under-paint corrosion

A confocal micro-XRF method combined with two individual polycapillary lenses was applied to steel sheets coated with anti-corrosive paint in order to nondestructively observe 3D elemental distribution of paint steels and corroded paint-coated steels. Nondestructive depth analysis and 3D elemental mapping of the painted steel sheets were demonstrated under the confocal XRF configuration. Three different painted steel sheets were prepared by cation electrodeposition coating for automotive onto flat steel sheets modified with a zinc phosphate conversion coating. These painted sheets were then caused to corrode by means of accelerated exposure to a salt bath (5 mass% NaCl) at 55°C for 240 hours. Depth elemental profiles of Ti, Zn, and Fe obtained by confocal micro-XRF measurements were in excellent agreement with that of the prepared sample. Elemental depth profiles and maps of the corroded painted sheets showed some blisters caused by crevice corrosion, which started from the site of a scratch. The distributions of Ti and Fe were approximately homogeneous in both the paint layer and the steel substrate, while the distributions of Zn, Mn, Ca, and Cl were heterogeneous.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Actionneur, Actuator, Accionador, Modélisation, Modeling, Modelización, Planéité, Flatness, Planeidad, Ebenheit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vibration, Vibración, Schwingung, Zingage immersion, Hot dip galvanizing, Galvanización con cinc sumergido, Feuerverzinken, Krylov subspace, PPF control, electromagnetic actuator, model reduction, and strip vibration

In this paper, we propose active vibration control of a strip in a continuous galvanizing line (CGL) using positive position feedback (PPF) control. The control system includes five pairs of electromagnetic actuators and controllers. First, the overall system was modeled using the three-dimensional finite element modeling (FEM) package ANSYS. The Krylov subspace technique was then used to reduce the order of the model. Finally, PPF control was applied to control the vibration. The stability condition was derived from the stiffness matrix concept, which shows the relationship between the DC gain of the controller and that of the system. Root locus analysis was performed to validate the stability condition derived. The results of the software simulations and the experiments demonstrate the effectiveness of the proposed controller under various tension conditions.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Acier austénito ferritique, Austenitic ferritic steel, Acero ferrítico austenítico, Austenitisch ferritischer Stahl, Acier double phase, Dual phase steel, Acero doble fase, Dualphasenstahl, Acier inoxydable duplex, Duplex stainless steel, Acero inoxidable duplex, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Diffraction neutron, Neutron diffraction, Difracción neutrónica, Neutronenbeugung, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Déformation, Deformation, Deformación, Verformung, Ecrouissage, Work hardening, Endurecimiento en frío, In situ, Propriété mécanique, Mechanical properties, Propiedad mecánica, Propriété traction, Tensile property, Propiedad tracción, Zugeigenschaft, Rayonnement synchrotron, Synchrotron radiation, Radiación sincrotrón, Synchrotronstrahlung, Relation contrainte déformation, Stress strain relation, Relación tensión deformación, duplex stainless steel, neutron diffraction, stress partitioning, stress-strain curve, synchrotron white x-ray diffraction, and work hardening

To investigate the tensile deformation behavior of a lean duplex stainless steel (S32101) from the viewpoints of plastic deformability among phases or grains, we performed static tensile tests, in situ neutron diffraction, and white x-ray diffraction experiments at room temperature. In the static tensile tests, the S32101 steel displayed a larger uniform elongation and a better tensile strength―uniform elongation balance than a commercial SUS329J4L duplex stainless steel. A larger uniform elongation of S32101 is associated with the macroscopic work hardening behavior that a work hardening rate higher than the flow stress can maintain up until high true strains. From the experimental results of synchrotron radiation white x-ray diffraction experiments, the hard phase of S32101 was changed from the ferrite (α) phase to austenite (γ) one during tensile deformation. This led to a larger stress partitioning between the phases at the latter stage of deformation. From the experimental results of in situ neutron diffraction, it was found that the stress partitioning of the γ phase in the S32101 was the largest among the present results. Therefore, the larger work hardening rate of S32101 can be explained by the large stress partitioning of the γ phase, that between γ and a phases and γ volume fraction.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Bainite, Bainita, Bainit, Carbure, Carbides, Carburo, Carbid, Recuit, Annealing, Recocido, Gluehen, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Traitement thermique, Heat treatment, Tratamiento térmico, Waermebehandlung, Zingage immersion, Hot dip galvanizing, Galvanización con cinc sumergido, Feuerverzinken, annealing, carbide-free bainite, hot dip galvanizing, and steel

Recently, advanced high strength steels for automotive applications were designed to achieve a carbide-free bainitic microstructure after conventional thermo-mechanical processing and a continuous annealing treatment. The microstructure obtained consists of ferrite laths interwoven with thin films of untransformed retained austenite. The sufficiently tough matrix and the control of the heterogeneity in the microstructure allowed an optimum combination of strength, ductility, and formability to be achieved. However, this work probed that even using a devoted theoretical alloying, carbide-free bainitic steels are hardly compatible with a conventional hot dip galvanizing annealing process, without any consideration about Zn coatability and adherence. The hardenability of the designed alloys was insufficient in some cases and the amount of austenite retained in the microstructure was too low or/and mechanically too unstable for high ductility. As a consequence, the obtained mechanical properties were comparable to those in high-Si dual phase steels without a beneficial transformation induced plasticity effect.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Codépôt, Codeposition, Codeposición, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Milieu basique, Basic medium, Medio básico, Alkalisches Medium, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zincate, Zincates, anomalous codeposition, electrodeposition, nomal codeposition, underpotential deposition, zinc-cobalt alloys, and zincate

Electrodeposition behavior of Zn-Co alloys was investigated at current densities of 2-500 A•m-2 and a charge of 5 × 104 C•m-2 at 308 K in an unagitated zincate solution containing triethanolamine, which forms a stable complex with Co2+ ions. At current densities lower than 5 A•m-2, the Zn-Co alloys exhibited normal co-deposition behavior, with the electrochemically more noble Co being preferentially deposited. By contrast, at current densities higher than 6 A•m-2, they exhibited anomalous co-deposition behavior, with the electrochemically less noble Zn being preferentially deposited. The current efficiency for Zn-Co alloy deposition was low (about 20%) in the normal co-deposition region, while it was 95% in the anomalous co-deposition region. Also, in the anomalous co-deposition region, the partial polarization curves for Co deposition and H2 evolution were significantly shifted to the less noble direction by the coexistence of Zn2+ ions, suggesting the formation of an inhibitor species that results from the presence of Zn2+ ions in the cathode layer. On the other hand, in the normal co-deposition region, the underpotential deposition of Zn apparently occured simultaneously with Co deposition. Zn-Co alloys are composed of stable intermetallic compounds CoZn13 and Co5Zn21; therefore, the activity coefficient of Zn in the deposits appears to decrease remarkably.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Amine, Amina, Codépôt, Codeposition, Codeposición, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Milieu basique, Basic medium, Medio básico, Alkalisches Medium, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zincate, Zincates, anomalous codeposition, electrodeposition, ethylenediamine, nomal codeposition, triethanolamine, underpotential deposition, zinc-nickel alloys, and zincate

Electrodeposition behavior of Zn-Ni alloys was investigated at current densities of 5-500 A•m-2 and a charge of 5 × 104 C•m-2 at 308 K in an unagitated zincate solution containing ethylenediamine (EDA), which forms a stable complex with Ni2+ ions. In the case of the TEA solution, the Zn-Ni alloy exhibited normal codeposition at low current densities, wherein electrochemically more noble Ni deposited preferentially, while it exhibited anomalous codeposition at high current densities, wherein less noble Zn deposited preferentially. In the EDA solution, the alloy exhibited anomalous codeposition at high current densities; on the other hand, even at low current densities, the Ni content in the deposit was almost identical with the composition reference line, showing a behavior similar to anomalous codeposition. In the EDA solution, Ni deposition and H2 evolution were significantly suppressed over a larger region of current densities, showing the formation of an inhibitor for deposition, which results from Zn2+ ions in the cathode layer. The dependence of the current efficiency for alloy deposition on the current density was smaller in the EDA solution than in that containing TEA. In the TEA solution, the underpotential deposition of Zn apparently occurred with Ni, while in the EDA solution, the underpotential deposition of Zn never occurred, because Ni deposition was suppressed by the coexistence of Zn2+ ions even at low current densities. The throwing power of Zn-Ni alloys in the EDA solution was better than that in the TEA solution.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Nettoyage. Dégraissage. Décapage, Cleaning. Degreasing. Pickling, Champ électrique, Electric field, Campo eléctrico, Elektrisches Feld, Nettoyage surface, Surface cleaning, Limpieza superficie, Oberflaechenreinigen, Potentiel électrique, Electric potential, Potencial eléctrico, Elektrisches Potential, Scorie, Slag, Escoria, Schlacke, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, copper slag cleaning, electric potential gradient, electrocapillary phenomenon, and electrolysis

The behaviors of molten copper slag under the vertical electric field were investigated in this paper. The presence of the electric field could accelerate the migration of copper drops from anode region to the cathode. Electrolysis reaction of molten copper slag was occurred at the interface of electrode and the molten slags. The copper slag cleaning process would be promoted in the electric field due to the electrocapillary and a certain degree of electrolysis. The Physical and chemical processes of copper slag cleaning under the vertical electric field was also summarized in the article.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Propriétés mécaniques. Rhéologie. Mécanique de la rupture. Tribologie, Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology, Propriété mécanique, Mechanical properties, Propiedad mecánica, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Acier austénitique, Austenitic steel, Acero austenítico, Austenitischer Stahl, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Ecrouissage, Work hardening, Endurecimiento en frío, Maclage, Twinning, Chocleo, Zwillingsbildung, Plasticité, Plasticity, Plasticidad, Plastizitaet, Vieillissement, Ageing, Envejecimiento, Altern, austenitic steel, dynamic strain aging, high Mn steel, high carbon, twinning-induced plasticity, and work hardening

We investigated the correlation among deformation twin density, work hardening, and tensile ductility in an Fe―18Mn―1.2C twinning-induced-plasticity (TWIP) steel, and discussed the correlation with the plastic instability condition. The deformation twin density was varied by changing the deformation temperature from 123 to 523 K. An important factor for the uniform elongation is the work hardening rate in a later deformation stage. The increase in the deformation twin density enhanced the work hardening rate significantly but not monotonically just before the fracture, since the deformation twin density is saturated against plastic strain. In addition, dynamic strain aging in a later deformation stage and ε-martensitic transformation were found to accelerate the fracture due to the localized deformation and the premature fracture, respectively. Accordingly, the relationship between uniform elongation and deformation twin density was not simple. The optimum conditions for the TWIP effect were concluded to be (1) considerable amount of deformation twinning in a later deformation stage, (2) suppression of dynamic strain aging in a later deformation stage, and (3) inhibition of ε-martensitic transformation.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Analyse contrainte, Stress analysis, Análisis tensión, Spannungsanalyse, Condition opératoire, Operating conditions, Condición operatoria, Contrainte résiduelle, Residual stress, Tensión residual, Eigenspannung, Dépôt physique phase vapeur, Physical vapor deposition, Deposición física fase vapor, Physikalisches Aufdampfen, Fonte graphite sphéroïdal, Ductile cast iron, Fundición grafítica esferoidal, Gusseisen mit Kugelgraphit, Rectification surface, Grinding, Rectificación superficie, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Trempe étagée bainitique, Austempering, Temple escalonado bainítico, Isothermisches Bainitumwandeln, Usinage, Machining, Mecanizado, Zerspanen, CrN, PVD processing parameters, TiN, austempered ductile iron, grinding, and residual stresses

The aim of this work is to study residual stresses (RS) in PVD TiN and CrN coated ADI substrates with different nodule counts, austempering temperatures and surface finishing methods (grinding and polishing). Coatings were applied by arc ion plating using an industrial reactor and different sets of processing parameters. Residual stress measurements were performed by x-ray diffraction using the sin2ψ method along two principal axes on the samples surface (parallel and perpendicular to the substrate abrasion direction). The film thickness, hardness and adhesion of each coated sample were also evaluated. The results obtained indicate that RS in TiN and CrN coated samples are compressive irrespective of the different substrates, surface finishing methods and processing parameters utilized. The parallel and perpendicular RS do not vary significantly, indicating a rotationally symmetric biaxial stress state. The RS of the coated samples are not influenced by the different substrate characteristics regarding microstructure, hardness and surface roughness. The microhardness and RS of TiN and CrN coated samples increase with film thickness. The increase in substrate temperature together with the decrease in the values of BIAS voltage, arc current and chamber pressure lead to microhardness and RS reduction. Grinding produces surface hardening and reduction of the compressive RS in the substrates, but causes no variations in the RS of the TiN and CrN coated samples. The adhesion strength quality of TiN and CrN coatings to ADI substrates can be related to indices ranging from HF1 to HF2.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Austénite, Austenite, Austenita, Austenit, Cinétique, Kinetics, Cinética, Kinetik, Durcissement déformation, Strain hardening, Endurecimiento deformación, Verfestigung, Ecrouissage, Work hardening, Endurecimiento en frío, Grande vitesse, High speed, Gran velocidad, Microstructure, Microestructura, Mikrogefuege, Modèle physique, Physical model, Modelo físico, Modélisation, Modeling, Modelización, Recristallisation dynamique, Dynamical recrystallization, Recristalización dinamica, Dynamische Rekristallisation, Simulation, Simulación, Vitesse déformation, Strain rate, Velocidad deformación, Verformungsgeschwindigkeit, austenite flow curve modeling, avrami kinetics, dynamic recrystallization, high strain rates, and work hardening parameters

Hot compression tests were carried out on three steels: i) a 0.038% Nb-0.11 %C microalloyed grade; ii) a Nb-modified TRIP steel; and iii) a Ti-stabilized low carbon steel. The tests were performed at strain rates up to 1 s―1 and over the temperature range 880―1 200°C. The initiation of dynamic recrystallization (DRX) was observed under all testing conditions. Two sets of equations were derived from the experimental curves: i) a work hardening relation pertaining to the grains in which DRX has not yet nucleated; and ii) a separate work hardening expression describing the mean flow stress applicable to the grains in which DRX is taking place. With the aid of the temperature and strain rate dependences determined from the data, and using the law of mixtures, extrapolated flow curves were calculated applicable to strain rates up to 100 s―1, i.e. to those involved in strip mill rolling. The simulations show that, once DRX has been initiated, the flow stress is controlled by the kinetics of the softening mechanisms.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Air, Aire, Luft, Méthode contrôle, Control method, Método control, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vibration, Vibración, Schwingung, Zingage immersion, Hot dip galvanizing, Galvanización con cinc sumergido, Feuerverzinken, averaging method, strip speed, strip tension, touch roll, and wind load of air knife

Nonlinear vibration of axially moving steel strip with tension near the air knife box during continuous hot-dip galvanizing process is investigated. A model of strip vibration for cooling section is established. Governing equations of the model are derived through the Hamilton's principle. Effect of speed, tension, molten zinc, oscillation of touch rolls and nonlinear wind load on strip vibration is considered. The reason-ability of boundary conditions of the model is confirmed by comparison of results from theoretical method and numerical simulation. Averaging method is employed in solving the equations and obtaining displacement response. The relation between amplitude near the air knife and production parameters is studied and further solutions of vibration control is presented. The research reveals that speed of strip has noticeable effect on amplitude near the air knife. It will be more difficult to reduce vibration with the increase of speed. Larger tension is in favor of keeping away from peaks of amplitude by using speed adjustment. A scheme of vibration control based upon averaging method can meet the requirement of production. A vibration suppression proposal by improving support stiffness of touch rolls is suggested.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Condition opératoire, Operating conditions, Condición operatoria, Dépôt physique phase vapeur, Physical vapor deposition, Deposición física fase vapor, Physikalisches Aufdampfen, Fonte graphite sphéroïdal, Ductile cast iron, Fundición grafítica esferoidal, Gusseisen mit Kugelgraphit, Microstructure, Microestructura, Mikrogefuege, Nitrure de titane, Titanium nitride, Titanio nitruro, Titannitrid, Revêtement non métallique, Non metal coating, Revestimiento no metálico, Nichtmetallischer Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Trempe étagée bainitique, Austempering, Temple escalonado bainítico, Isothermisches Bainitumwandeln, CrN, PVD processing parameters, TiN, and austempered ductile iron

This work studies the influence of the PVD processing parameters on the characteristics of TiN and CrN coatings deposited on ADI substrates, austempered at 360°C, with different nodule counts and surface roughnesses. Coatings were applied by arc ion plating using an industrial reactor and different sets of parameters, with BIAS voltages, arc currents, chamber pressures and substrate temperatures varying from - 100 to -250 V, 60 to 65 A, 0.7 to 2.8 Pa and 280 to 450°C, respectively. The effect of the different depositions conditions on the substrates microstructure was also analyzed. The existing phases, preferred orientation, surface topography, film thickness, hardness and adhesion of each coating were determined. The retained austenite content and hardness of each substrate were computed before and after coating deposition. The results obtained indicate that the different deposition conditions and coating materials evaluated do not generate significant changes neither in the resulting topography nor in the coating adhesion, which can be related to indices between HF1 and HF2. Coating adhesion was not affected by different substrate roughnesses. The combined reduction of BIAS voltage, arc current and chamber pressure leads to a decrease of TiN growth rate and hardness, while high substrate temperatures promotes an increase in TiN and CrN growth rates. Substrate temperatures around 300°C with deposition times of up to 240 min do not promote noticeable changes on the ausferritic microstructure, while temperatures of 400°C and above translate into a clear microstructural deterioration, even for short deposition times.