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  • 101.
    Frisk, Karin
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Angré, Alexander
    RISE, Swerea, Swerea KIMAB AB.
    Mild, Erik
    RISE, Swerea, Swerea KIMAB AB.
    Lindberg, Fredrik
    RISE, Swerea, Swerea KIMAB AB.
    Eggertson, Christer
    RISE, Swerea, Swerea KIMAB AB.
    Oxygen in pilot-scale gas atomised powders - Study of oxygen uptake and oxide characterisation2011Ingår i: Proceedings of the Euro International Powder Metallurgy Congress and Exhibition, Euro PM 2011, European Powder Metallurgy Association (EPMA) , 2011, Vol. 3Konferensbidrag (Refereegranskat)
    Abstract [en]

    Properties of steel are detrimentally affected by oxygen and the content should be minimised. The effect of oxygen on steel properties depends on the type of steel, on the amount of dissolved oxygen and on the type and size of oxides, and on microstructure. In steel produced from powder, surface oxides on the powder grains, dissolved oxygen as well as oxide inclusions originating from the melt contribute to the total oxygen content. It is therefore interesting to investigate under what conditions oxygen uptake takes place, and how oxides are formed and can be characterised. A lab scale atomizer with a maximum charge weight of approximately 10 kg has been used. Powder atomisations have been performed, using an oxysensor to monitor the oxygen levels at different positions in the atomisation equipment, and melt samples have been extracted. Oxygen in the powder is characterised using Photo Acoustic Spectroscopy (PAS), by analysing oxygen contents in powder and in compacted samples, and by microstructure investigations.

  • 102.
    Frisk, Karin
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Eggertson, Christer
    RISE, Swerea, Swerea KIMAB AB.
    Gårdstam, Johannes
    RISE, Swerea, Swerea KIMAB AB.
    Caddeo, Sophie
    RISE, Swerea, Swerea KIMAB AB.
    Simulation of oxygen reduction in PM-HIP materials2010Ingår i: Proceedings of the World Powder Metallurgy Congress and Exhibition, World PM 2010, European Powder Metallurgy Association (EPMA) , 2010, Vol. 5Konferensbidrag (Refereegranskat)
    Abstract [en]

    A challenge in the development of powder based materials is to limit the oxygen contents. In the present work reduction of oxygen/oxides in a duplex stainless steel powder was studied. The main mechanisms ruling the reduction of oxygen in a hydrogen atmosphere have been established. A combination of experiments and mathematical modelling was used. Experiments were performed on small samples of powder, as well as powder encapsulated in a 200x200 mm canister. FEM calculations of the heat transfer in the canister, combined with thermodynamic calculations of the stability, and heat of reduction of oxides were used for the modelling. The experimental features: oxide reduction, heat transfer, and hydrogen transport, are reproduced by the calculations. A high-oxygen powder was used for the experiments, and the oxygen content was reduced from 200 ppm O in the powder, to less than 100 ppm O in the compacted material. The results from the modelling could conclude that this was due to a reduction of Fe-oxides at low temperatures, and Cr-oxides at high temperatures.

  • 103.
    Frisk, Karin
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Luo, Chunhui
    RISE, Swerea, Swerea KIMAB AB.
    Johansson, S.C.
    RISE, Swerea, Swerea KIMAB AB.
    Haglund, Sven
    RISE, Swerea, Swerea KIMAB AB.
    Petterson, Niklas
    RISE, Swerea, Swerea KIMAB AB.
    Strandell, I.
    AB SKF.
    Compound materials by PM-HIP2014Ingår i: Powder Metallurgy, ISSN 0032-5899, E-ISSN 1743-2901, Vol. 57, nr 5, s. 341-347Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There are many applications where compound materials can be of interest, for example when different properties are needed in different parts of a component. Compound materials can be produced by hot isostatic pressing (HIP) of powder metallurgical materials. One aspect that should be considered in the design is the quality of the interface between the two different material compositions. Diffusion during HIP can cause formation of brittle phases in the interface or deteriorate properties by diffusion of alloying elements. The present work shows results from a study where different steel types were joined (quench and temper steel/air hardening steel/bearing steel with a tool steel/corrosion resistant martensitic steel). The evaluation was performed by computational predictions and by small scale HIP experiments that were evaluated by microstructure analysis and chemical analysis. © 2014 Institute of Materials, Minerals and Mining.

  • 104.
    Frisk, Karin
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Markström, Andreas
    RISE, Swerea, Swerea KIMAB AB.
    Effect of Cr and v on phase equilibria in Co-WC based hardmetals2008Ingår i: International Journal of Materials Research - Zeitschrift für Metallkunde, ISSN 1862-5282, E-ISSN 2195-8556, Vol. 99, nr 3, s. 287-293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New measurements of the influence of Cr and V on the melting temperature of the binder phase in Co-based hardmetals are presented. It was shown that both Cr and V affect the melting temperature significantly. Cr decreases the melting temperature by over 100°C, and V by approximately 40°C. This is due to the high solubility of Cr and V in liquid Co, and this solubility was determined by experiments and calculations. The solubility of Cr in solid fccCo is also discussed, as well as the composition of the MC, M7C3 and the M6C carbides in alloys with Cr and V. The new experimental information is used to obtain a reliable thermodynamic description of the binder phase (Co-rich) in C-Co-Cr-W and C-Co-V-W alloys. Calculated equilibria are compared with experiments. © Carl Hanser Verlag GmbH & Co. KG.

  • 105.
    Frisk, Karin
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Söderberg, Hans
    RISE, Swerea, Swerea KIMAB AB.
    Caddeo, Sophie
    RISE, Swerea, Swerea KIMAB AB.
    Studies of surface oxides on steel powders using photo acoustic spectroscopy coupled with thermodynamic calculations2009Ingår i: Proceedings of the Euro International Powder Metallurgy Congress and Exhibition, Euro PM 2009, European Powder Metallurgy Association (EPMA) , 2009, Vol. 3Konferensbidrag (Refereegranskat)
    Abstract [en]

    The properties of PM steel are affected by the oxygen content of the material. The surface oxides on the powder grains are an important source of oxygen in steel produced from powder, and it is therefore interesting to investigate under what conditions the surface oxides are formed, and can be reduced. In the present work Photo Acoustic Spectroscopy (PAS) studies were used to study surface oxides on powders. The measurements were coupled with thermodynamic calculations, to identify the type of oxides. The use of the PAS instrument is a novel technique for gas analysis at ppm levels under controlled atmospheres and heat treatments. Examples are shown from studies of oxide reduction, furnace atmosphere control, and moisture uptake. Sintered steel, stainless steel, and low alloyed steels were investigated. The accuracy and reproducibility of the method for different applications is assessed.

  • 106.
    Fuertes Casals, Nuria
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Nazarov, Andrej
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Vucko, Flavien
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Pettersson, Rachel
    Jernkontoret, Sweden.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Influence of mechanical stress on the potential distribution on a 301 LN stainless steel surface2015Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 162, nr 9, s. C465-C472Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of the present work was to study the influence of the stress on the electrode potential of the austenitic stainless steel 301LN using Scanning Kelvin Probe (SKP). It was found that elastic deformation reversibly ennobles the potential whereas plastic deformation decreases the potential in both tensile and compressive deformation mode and this decrease is retained even 24 h after removal of the load. To interpret the stress effects, different surface preparations were used and the composition and thickness of the passive film were determined by GDOES. Slip steps formed due to plastic deformation were observed using AFM. The effect of plastic strain on the potential is explained by the formation of dislocations, which creates more a defective passive film.

  • 107.
    Fuertes, N.
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Bengtsson, V.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Pettersson, R.
    Jernkontoret, Sweden.
    Rohwerder, M.
    MPI, Germany.
    Use of SVET to evaluate corrosion resistance of heat tinted stainless steel welds and effect of post-weld cleaning2017Ingår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 68, nr 1, s. 7-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of heat tints on the corrosion resistance of a 2507 duplex stainless steel tungsten inert gas (TIG) welded joint was assessed. The scanning vibrating electrode technique (SVET) was used to study oxide dissolution, initiation and propagation of corrosion on the weld. Small spot X-ray photoelectron spectroscopy (XPS) was used to investigate the composition and thickness of the heat tints. Both heat tinted and post-weld cleaned conditions were tested. Post-weld cleaning methods investigated were brushing, brushing plus polishing and brushing plus pickling paste. It was seen that heat tints dissolve by electrochemical reactions that can be mapped with the SVET and correlated with the level of discolouration of the oxides, with the purple–brown oxide being the most active. The mechanical post-weld cleaning methods proved to be insufficient to remove the anodic activity in the heat tint. The most efficient process was brushing followed by pickling which resulted in a totally passive surface measured with SVET and a higher critical pitting temperature.

  • 108.
    Garcia, J.
    et al.
    Helmholtz-Zentrum Berlin für Materialien und Energie GmbH.
    Lindwall, Greta
    RISE, Swerea, Swerea KIMAB AB.
    Prat, O.
    Max Planck Institute für Eisenforschung GmbH.
    Frisk, Karin
    RISE, Swerea, Swerea KIMAB AB.
    Kinetics of formation of graded layers on cemented carbides: Experimental investigations and DICTRA simulations2011Ingår i: International Journal of Refractory Metals and Hard Materials, ISSN 2634368, Vol. 29, nr 2, s. 256-259Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Kinetics of formation of fcc-free layers on Co-W-Ti-Ta-Nb-C-N cemented carbides was investigated by experimental methods and DICTRA simulations. The layer formation obeys a parabolic law, indicating a diffusion-controlled process. For DICTRA simulations, the influence of the mobilities for all diffusing elements in the liquid binder phase at the sintering temperature was investigated. The best agreement between experimental and simulations was obtained considering that the mobility of all metallic elements is two times slower compared with the mobility of the non-metallic elements. © 2010 Elsevier Ltd. All rights reserved.

  • 109.
    Ghader, Heravi
    RISE, Swerea, Swerea KIMAB AB.
    Improvement of technique and evaluation methods for Gradient Solidification of Carbon Steels - Master Thesis2013Rapport (Refereegranskat)
    Abstract [sv]

    Carbon steels with carbon content between 0.1% and 0.5% are highly susceptible to surface cracks during continuous casting. This is due to the volume contraction caused by peritectic transformation during solidification. Due to the high cooling rates in continuous casting, the experimental description of phase evolution during solidification is difficult. In this study directional solidification experiments are conducted to simulate the microstructural evolution and subsequent solid state phase transformation in continuous casting for three grades of carbon steel. Additionally a well-function method is developed for sample preparation for gradient solidification experiments and bar-shape samples are provided through quartz tubes. Directional solidification experiments with different cooling rates are conducted in a furnace and quenched at the end of process. The solidification of the alloys was observed to start with formation of primary ferrite and followed by the peritectic reaction. During the solidification the γ phase was formed on the δ surface along the δ/L interface and completely surrounded the δ/L interface. The growth of γ phase on the δ phase continued throughout the peritectic transformation and under the certain conditions the γ phase grew by upward direct solidification from the liquid. The fine structure ahead of the solidification front caused by quenching of the melt at the end of process was a help to distinguish L/S interval. The distance between the solidification front and two phase region where the solidification is complete was estimated to be around 7- 10 mm.

  • 110.
    Gholi, A.R.
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Lindvall, Greta
    RISE, Swerea, Swerea KIMAB AB.
    Jönsson, Martin
    RISE, Swerea, Swerea KIMAB AB.
    Effects of tempering on corrosion properties of high nitrogen alloyed tooling steels in pyrolysis oil2011Ingår i: European Corrosion Congress 2011, EUROCORR 2011, 2011, Vol. 2, s. 982-994Konferensbidrag (Refereegranskat)
    Abstract [en]

    Due to environmental issues the interest for Bio fuels has increased in recent years. Fast pyrolysis is the process of converting biomass to biofuel by rapid heating at elevated temperatures (about 400°C) in absence of oxygen. However, high water content, low pH, and the presence of metal ions and chlorides make the Pyrolysis oil highly corrosive. In addition, the Pyrolysis oil can be highly abrasive due to residues from the pyrolysis process. Hence, materials currently used in the fuel system in ordinary combustion engines cannot withstand the harsh environment connected to the use of pyrolysis oil. In this study four different tool steel grades have been tested in the pyrolysis oil; Vanax 35, Vanax 75, Elmax and AISI O1, of which Vanax 35 and 75, newly developed at Uddeholms AB, are high nitrogen alloyed grades. After austenitizing the tool steels have been tempered at different temperatures in order to try to optimize the corrosion properties and the wear resistance. Samples of the steels have then been exposed in autoclaves at 4 different temperatures, 20°C, 70°C, 95°C and 13o°C to mimic the temperature at different parts of the fuel system. The measurements show that the corrosion rate is considerable lower for the two Vanax steels compared to the Elmax and the AISI 01 steels, who suffered a high rate of general corrosion. Of the Vanax materials the steels tempered at lower temperatures (200°C, 400°C and 450°C) show the best corrosion resistance whereas higher tempering temperatures, like 500°C, show a h igher mass loss. Thermodynamic calculations suggest that the improved corrosion resistance for the Vanax materials is due to formation of primary vanadium rich nitrides instead of primary chromium rich carbides at the austenitizing temperature. Consequently, for the Vanax group, higher amounts of chromium are dissolved in solid solution after quench which will help facilitating repassivation. The poorer corrosion properties at higher tempering ranges is probably due to the precipitation of chromium rich secondary phases during tempering, which reduces the chromium content of the martensitic matrix.

  • 111.
    Gil, H.
    et al.
    Royal Institute of Technology (KTH).
    Leygraf, C.
    Royal Institute of Technology (KTH).
    Tidblad, Johan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    GILDES model simulations of the atmospheric corrosion of copper induced by low concentrations of carboxylic acids2011Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 158, nr 12, s. C429-C438Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A computer simulation with a GILDES-based model using the COMSOL multiphysics software was performed for copper exposed to low concentrations of carboxylic acids in humidified air at room temperature. GILDES is a six-regime computer model (Gas, the Interface between gas and liquid, the Liquid, the Deposition layer, the Electrodic region near the surface and the Solid). The simulations were compared to previously published in-situ results for copper at the same conditions analysed by a quartz crystal microbalance (QCM) and infrared reflection absorption spectroscopy (IRAS). Experimental and calculated results agree with each other with respect to the effect of corrosion, showing formic acid as the most aggressive followed by acetic and propionic acid. This is supported by a higher ligand- and proton-promoted dissolution found in formic acid exposures, followed by acetic and propionic exposures. The dominating precipitated phases were Cu2O, Cu(OH)2, Cu(CH 3COO)2 H2O, Cu(HCOO)2 4H 2O and Cu(CH3CH2COO)2 H 2O. Besides Cu2O, the simulations suggest that the hydrated form of the respective carboxylates is the most likely compound to be formed in this type of atmospheres. © 2011 The Electrochemical Society.

  • 112.
    Gil, H.
    et al.
    Royal Institute of Technology (KTH).
    Leygraf, C.
    Royal Institute of Technology (KTH).
    Tidblad, Johan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    GILDES model simulations of the atmospheric corrosion of zinc induced by low concentrations of carboxylic acids2012Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 159, nr 3, s. C123-C128Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The GILDES computer based model was successfully applied to the atmospheric corrosion of zinc exposed to low concentrations of carboxylic acids in humidified air at room temperature. Under these exposure conditions the expected precipitated phases are zinc oxide (ZnO), zinc hydroxide (Zn(OH) 2) and several forms of hydrated zinc carboxylate, Zn(CH 3CH 2COO) 22H 2O, Zn(CH 3COO) 22H 2O and Zn(HCOO) 22H 2O. The results were compared to those from laboratory exposures obtained in the same conditions. The model correctly predicts the trend for ZnO and zinc carboxylate formation found in experimental exposures for the three acids tested. According to the simulations, surface protonation, surface acid base reactions, as well as ligand- and proton- induced dissolution reactions play a major role in the initial atmospheric corrosion of zinc. Henrys law constant (K H) is found to be an important parameter but uncertain due to different reported literature values. When K H is increased the formation rate of zinc carboxylate also increases. K H increases in the sequence propionic acid acetic acid formic acid, the same order as found for the calculated dissolution rate. © 2012 The Electrochemical Society.

  • 113.
    Goidanich, Sara
    et al.
    Politecnico di Milano, Italy.
    Odnevall Wallinder, Inger
    KTH Royal Institute of Technology, Stockholm.
    Arenas, Maria Angeles
    CSIC Centro Nacional de Investigaciones Metalurgica, Spain.
    De Damborenea, Juan
    CSIC Centro Nacional de Investigaciones Metalurgica, Spain.
    Ormellese, Marco
    Politecnico di Milano, Italy.
    Sanchez Amaya, Jose Maria
    CASEM, Spain.
    Botana Pedemonte, Francisco Javier
    CASEM, Spain.
    Le Bozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Effect of the environment on the metal release and corrosion behaviour of different copper-based alloys: Field exposures at 5 different test sites in Europe2008Ingår i: 17th International Corrosion Congress 2008: Corrosion Control in the Service of Society, 2008, s. 102-115Konferensbidrag (Refereegranskat)
    Abstract [en]

    Diffuse emissions and dispersion of metals from different sources in the society have lately received an increased concern from an environmental perspective. Large research efforts have been initiated and undertaken by the division of Corrosion Science at KTH to fill knowledge gaps on corrosion-induced metal release from external constructions and buildings. The generation of such data is of paramount importance for the on-going assessment of flows and potential adverse environmental effects caused by released metals. Generated information is also essential for an improved understanding of prevailing atmospheric corrosion processes of importance for the preservation of our cultural heritage, e.g. bronze statues exposed to the atmosphere. This paper summarizes and compares long-term metal release data from pure copper, bronze (6%wt Sn) and brass (20%wt Zn) exposed at unsheltered conditions in five European environments of significantly different climatic and pollutant conditions; three urban sites (Stockholm-Sweden, Milan-Italy and Madrid-Spain) and two marine sites (Brest-France, Cadiz-Spain). Generated data are interpreted with respect to parallel multi-analytical studies of changes in patina characteristics, corrosion rates and differences in prevailing environmental conditions.

  • 114.
    Granbom, Y.
    et al.
    SSAB Strip Product Division.
    Ryde, Lena
    RISE, Swerea, Swerea KIMAB AB.
    Jeppsson, J.
    Royal Institute of Technology.
    Simulation of the soaking and gas jet cooling in a continuous annealing line using dilatometry2010Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 81, nr 2, s. 158-167Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present study concerns the simulation of a continuous annealing line (CAL), using dilatometry. Simulations of CAL have been performed on four commercial steel grades with different chemical compositions in order to investigate how the alloying elements C, Mn, Si and B affect the microstructure and hardness of dual phase (DP) and martensitic steels. Three annealing cycles corresponding to those used in a CAL have been applied. When annealing intercritically, as is the case in DP-steel production, the materials do not reach equilibrium during soaking. Mn and C increase the austenite content and consequently the hardness of the materials. Higher levels of Si (0.4 wt %) are required to retard the formation of new ferrite during cooling in the gas jet section, prior to quenching. B increases hardenability effectively when annealing in the austenite region but is not as efficient during intercritical annealing, which implies that boron restrains ferrite nucleation rather than impeding ferrite growth. Results from DICTRA calculations show that it is possible to simulate the phase transformations during soaking, gasjet cooling and quenching. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 115.
    Grøntoft, Terje
    et al.
    NILU Norwegian institute for air research, Sweden.
    Verney-Carron, Aurelie
    CNRS Université Paris-Est, France.
    Tidblad, Johan
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Cleaning costs for European sheltered white painted steel and modern glass surfaces due to air pollution since the year 20002019Ingår i: Atmosphere, ISSN 2073-4433, E-ISSN 2073-4433, Vol. 10, nr 4, artikel-id 167Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports estimated maintenance-cleaning costs, cost savings and cleaning interval increases for structural surfaces and windows in Europe obtainable by reducing the air pollution. Methodology and data from the ICP-materials project were used. The average present (2018) cleaning costs for sheltered white painted steel surfaces and modern glass due to air pollution over background, was estimated to be ~2.5 Euro/m 2 ·year. Hypothetical 50% reduction in the air pollution was found to give savings in these cleaning costs of ~1.5 Euro/m 2 ·year. Observed reduction in the air pollution, from 2002-2005 until 2011-2014, have probably increased the cleaning interval for white painted steel with ~100% (from 12 to 24 years), representing reductions in the single intervention cleaning costs from 7 to 4%/year (= % of one cleaning investment, per year during the cleaning interval) and for the modern glass with ~65% (from 0.85 to 1.3 years), representing reductions in the cleaning cost from 124 to 95%/year. The cleaning cost reductions, obtainable by 50% reduction in air pollution, would have been ~3 %/year for white painted steel and ~60%/year for the modern glass, representing ~100 and 50% additional cleaning interval increases. These potential cleaning cost savings are significantly higher than previously reported for the weathering of Portland limestone ornament and zinc monuments.

  • 116.
    Gurell, Jonas
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Bengtson, Arne
    Falkenström, Magnus
    IR-teknik för direkt mätning av ämnestemperatur och ugnsatmosfär i värmningsugnar2012Rapport (Refereegranskat)
    Abstract [sv]

    Infraröd(IR) strålning är elektromagnetisk(EM) strålning i våglängdsintervallet 0,75– 1000μm. Omedelbart under detta område har vi synligt ljus, omedelbart ovanför mikrovågor som är de mest kortvågiga av det område som benämns radiovågor. All materia avger (emitterar) och absorberar IR-strålning, och såväl emissions- som absorptionsspektra är starkt temperaturberoende. Det är därför vanligt med kontaktlös temperaturmätning baserad på IR–teknik. Under senare år har en betydande teknisk utveckling skett, både av optiska system och detektorer. För höga temperaturer är den vanligaste mättekniken s.k. pyrometri, vilken är baserad på mätning av emission från mätobjektet. Ursprungligen var detta en teknik enbart för mätning av mycket heta fasta föremål med strålning i det synliga området, baserat på att man visuellt jämförde objektets färg med en glödtråd som hettats upp successivt. Med utvecklingen av känsliga IR–detektorer har pyrometrin expanderat till IR–området. All emission av EM strålning beskrivs av kvantmekaniken, som säger att varje fysikaliskt system endast kan anta ett begränsat antal diskreta energitillstånd. Fasta kroppar har ett mycket stort antal s.k. frihetsgrader, och därmed också ett närmast oändligt antal möjliga energitillstånd. Fördelningen av energitillstånd följer den s.k. Boltzmann-statistiken. Ju högre temperatur, desto högre energitillstånd populeras, vilket i sin tur innebär att EM strålning med allt kortare våglängd emitteras.

  • 117.
    Gurell, Jonas
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Bengtson, Arne
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Falkenström, Magnus
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Hansson, B.A.M.
    RISE., Swedish ICT, Acreo.
    Laser induced breakdown spectroscopy for fast elemental analysis and sorting of metallic scrap pieces using certified reference materials2012Ingår i: Spectrochimica Acta Part B - Atomic Spectroscopy, ISSN 0584-8547, E-ISSN 1873-3565, Vol. 74-75, s. 46-50Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A setup utilizing laser induced breakdown spectroscopy (LIBS) for performing elemental analysis in order to classify metallic samples is currently under construction. The setup uses short laser pulses to locally ablate the sample and create luminous plasmas. The emitted light is analyzed spectroscopically for instantaneous determination of the elemental composition. A table-top system based on a compact CCD spectrometer has been constructed and combined with fast software in order to test the concept of remote, single shot material classification with LIBS. Certified reference materials with known elemental compositions were used in the laboratory tests. We report on successful laboratory tests in which samples were classified using an analysis based on optical emission following a single laser pulse and with an operating distance of approximately 1 m. Details regarding field tests of this versatile and promising technique are discussed. © 2012 Elsevier B.V.

  • 118.
    Gurell, Jonas
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Bengtson, Arne
    RISE, Swerea, Swerea KIMAB AB.
    Lundin, Peter
    RISE, Swerea, Swerea KIMAB AB.
    Spectroscopy-based photonic instrumentation for the manufacturing industry: Contactless measurements of distances, temperatures, and chemical composition2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The steady progress in photonic components in terms of cost-to-performance ratio, maturity and robustness opens new avenues for the commercial deployment of photonic sensor systems in a wide range of industrial applications. Advanced sensing can be used to optimize complex processes and thereby enable significant savings in energy consumption. Three cases of robust photonic instrumentation for process optimization and quality control in manufacturing industries are presented: improved metal recycling with laser-induced breakdown spectroscopy, quality control in precision machining by white-light interferometry with optical fiber probes embedded in machining tools, and process optimization in steel foundries by stand-off temperature measurements in blast furnaces with optical fiber lances and spectral analysis techniques. Each of these methods utilizes a low-cost spectrometer, and requires dedicated calibration and signal processing methods to guarantee robust operation in industrial environments with varying conditions. Experimental results are presented, including on-line steel alloy analysis with correct classification rates in excess of 95%, distance measurements with axial resolution of +/- 2nm over a 75μm range, and continuous temperature monitoring of molten steel in oxygen blast furnaces with temperature measurement accuracy better than 1%. © 2014 SPIE.

  • 119.
    Gurell, Jonas
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Lundin, Peter
    RISE, Swerea, Swerea KIMAB AB.
    Falkenström, Magnus
    RISE, Swerea, Swerea KIMAB AB.
    Bengtson, Arne
    RISE, Swerea, Swerea KIMAB AB.
    Noharet, B.
    Fast and remote analysis of metals for efficient recycling - A laser spectroscopic setup for automated analysis of metallic scrap pieces2012Ingår i: 2012 Symposium on Photonics and Optoelectronics, SOPO 2012, 2012, artikel-id 6270469Konferensbidrag (Refereegranskat)
    Abstract [en]

    A setup for fast and remote elemental analysis of metallic scrap pieces is under development. The setup uses laser-induced breakdown spectroscopy in order to classify scrap pieces with the purpose of providing a better analysis and enabling sorting of recyclable metals. © 2012 IEEE.

  • 120.
    Gåsvaer, Daniel
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, IVF.
    Hedegård, Joakim
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Jönsson, Christina
    RISE - Research Institutes of Sweden, Material och produktion, IVF, Energi och miljö.
    Kurdve, Martin
    RISE - Research Institutes of Sweden, Material och produktion, IVF.
    Lundin, Roger
    RISE - Research Institutes of Sweden, Material och produktion, IVF.
    Persson, Kalle
    RISE - Research Institutes of Sweden, Material och produktion, IVF.
    Widfeldt, Magnus
    RISE - Research Institutes of Sweden, Material och produktion, IVF.
    Axelson, Jens
    RISE - Research Institutes of Sweden, Material och produktion, IVF.
    Att utveckla den smarta svetscellen: Lean, svetsteknik och automation2013Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    En svetscell producerar och är produktiv när svetsning pågår och ljubågen brinner. Då skapas värde i en svetscell. För att nå teknisk och ekonomisk framgång, behöver svetscellen fungera "smart" med effektiva flöden, hög tillgänglighet, optimerad svetsteknik och ur flera aspekter goda miljöegenskaper. Skriften fungerar som hjälp när företag vill utveckla sin svetsverkstad och förbättra svetsproduktionen, utifrån lean, svetsteknik och automation.

  • 121.
    Ha, H.
    et al.
    University of Virginia.
    Taxen, Claes
    RISE, Swerea, Swerea KIMAB AB.
    Williams, K.
    University of Virginia.
    Scully, J.
    University of Virginia.
    Effects of selected water chemistry variables on copper pitting propagation in potable water2011Ingår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 56, nr 17, s. 6165-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The pit propagation behavior of copper (UNS C11000) was investigated from an electrochemical perspective using the artificial pit method. Pit growth was studied systematically in a range of HCO 3 -, SO 4 2- and Cl - containing-waters at various concentrations. Pit propagation was mediated by the nature of the corrosion products formed both inside and over the pit mouth (i.e., cap). Certain water chemistry concentrations such as those high in sulfate were found to promote fast pitting that could be sustained over long times at a fixed applied potential but gradually stifled in all but the lowest concentration solutions. In contrast, Cl - containing waters without sulfate ions resulted in slower pit growth and eventual repassivation. These observations were interpreted through understanding of the identity, amount and porosity of corrosion products formed inside and over pits. These factors controlled their resistive nature as characterized using electrochemical impedance spectroscopy. A finite element model (FEM) was developed which included copper oxidation kinetics, transport by migration and diffusion, Cu(I) and Cu(II) solid corrosion product formation and porosity governed by equilibrium thermodynamics and a saturation index, as well as pit current and depth of penetration. The findings of the modeling were in good agreement with artificial pit experiments. Malachite, bronchantite, cuprite, nantokite and atacamite corrosion products were both observed in experiment and predicted by the model. Stifling and/or repassivation occurred when the resistance of the corrosion product layer became high enough to lower the pit bottom potential and pit current density such as 10 -5 A/cm 2 could be attained with thick and dense layer. The ramifications of these findings towards pit propagation characteristics in potable waters will be discussed with improved insight into the roles of Cl - and SO 4 2- ions. © 2011 Elsevier Ltd. All Rights Reserved.

  • 122.
    Ha, H.
    et al.
    University of Virginia.
    Taxén, Claes
    RISE, Swerea, Swerea KIMAB AB.
    Cong, H.
    University of Virginia.
    Scully, J.R.
    University of Virginia.
    Effect of applied potential on Pit propagation in copper as function of water chemistry2012Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 159, nr 2, s. C59-C73Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of potential on pit propagation as a function of water chemistry was investigated using artificial pit electrodes. In both 0.01 M HCO 3 - 0.01 M SO 4 2- and 0.01 M HCO 3 - 0.01 M Cl - solutions, pits grew faster at higher applied potentials. However the magnitude of the pitting rate depends on the solution chemistry. A higher pitting rate was observed during pit growth in 0.01 M HCO 3 - 0.01 M SO 4 2- solution compared to 0.01 M HCO 3 - 0.01 M Cl - solution. The chemistry of the water determined the morphology and the molecular identity of corrosion products deposited inside and outside of the pits. Thick and porous layers of malachite and brochantiteposnjakite covered pits in 0.01 M HCO 3 - 0.01 M SO 4 2- solution. In contrast, thin and compact layers of malachite, cuprite and atacamitenantokiteeriochantite covered pits in 0.01 M HCO 3 - 0.01 M Cl - solution. Modeling successfully predicted these corrosion products. Applied potential determined the amount, the structure and the distribution of corrosion products in both experiment and model. However, the effect of potential was more pronounced in 0.01 M HCO 3 - 0.01 M SO 4 2- solution in comparison to 0.01 M HCO 3 - 0.01 M Cl - solution. © 2011 The Electrochemical Society.

  • 123.
    Haglund, S.
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Kristoffersen, Hans
    RISE, Swerea, Swerea IVF AB.
    Simulation of residual stresses after straightening of induction hardened components2014Ingår i: HTM - Journal of Heat Treatment and Materials, ISSN 18672493, Vol. 69, nr 3, s. 165-172Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Straightening is a manufacturing process where a component is bent, and plastically deformed, in order to reach a desired straightness. It is an unwanted but in many cases necessary process. For instance heat treatment operations such as carburizing and induction hardening may give distortions of magnitude that a straightening operation is required. The main disadvantage with straightening, apart from the extra processing step, is that it alters the residual stresses which decrease the fatigue strength of the component. In this paper, the straightening of a surface hardened shaft is simulated by FEM. The paper brings new insight into the complexity in the changes in residual stress that deviates far from the simplified views presented in literature. It will be shown that there are fundamental differences between a through hardened shaft and a surface hardened one as well as between shafts with shallow and deep surface hardening depths. The material studied is 42CrMo4 induction hardened by single shot. It is shown that the change in residual stresses is rather complex with decreased compressive residual stresses in a number of locations around the circumference while other locations have increased stresses. The amount of change in the residual stresses are largely governed by the required bending but by doing the straightening operation in an optimal way the negative effect can be reduced. © 2014 Carl Hanser Verlag GmbH & Co. KG.

  • 124.
    Haglund, Sven
    RISE, Swerea, Swerea KIMAB AB.
    Extending the use of nitriding processes to reduce distortion and fuel consumption2012Ingår i: Quenching Control and Distortion - Proceedings of the 6th International Quenching and Control of Distortion Conference, Including the 4th International Distortion Engineering Conference, 2012, s. 785-791Konferensbidrag (Refereegranskat)
    Abstract [en]

    In order to meet requirements for lower fuel consumption, low friction powertrain-components are needed. Nitriding and nitrocarburizing are thermochemical heat treatment processes that enhance the surface properties, e.g. high resistance to adhesive and abrasive wear as well as low friction and high corrosion resistance, of steel components. Beside this, another benefit is low distortion of the heat treated components due to the low process temperature, which is below the austenitizing temperature. To take a better use of the benefits provided by nitriding processes, and to facilitate replacement of case carburizing which is more commonly used today, a better knowledge and understanding of the properties that are possible to achieve by the different nitriding processes, in combination to selection of steel grade, is needed. A major challenge for many components is how to obtain required strength properties, e.g high-strength fatigue properties, as can be achieved by case carburizing. In this work the influences on compound layer, diffusion zone and residual stresses have been evaluated for different steel grades after nitriding and nitrocarburizing. Copyright © 2012 ASM International® All rights reserved.

  • 125.
    Haglund, Sven
    RISE, Swerea, Swerea KIMAB AB.
    Fatigue properties of Austempered Ductile Iron (ADI)2011Rapport (Refereegranskat)
    Abstract [en]

    In this work ADI-iron has been studied with a main focus on fatigue properties. ADI is a rather new set of materials with in many cases improved properties as compared to standard iron, and may in some cases even replace wrought materials. The composition range, as well as heat treatment parameters is rather narrow so a careful production control is necessary. In the experimental part of this work the fatigue properties of an ADI treated iron (austenetised at 880°C and ADI treated at 400°C) has been tested on hour glass shaped specimens. The material exhibited a fatigue strength at 106 cycles of ~480 MPa (stress range, R=0), see figure A2. The fatigue initiation was controlled by defects, i.e. pores, in the material.

  • 126.
    Haglund, Sven
    RISE, Swerea, Swerea KIMAB AB.
    Influence of straightening on bending fatigue properties of induction hardened shafts in steel 42CrMo4 (SAE 4140)2012Ingår i: Quenching Control and Distortion - Proceedings of the 6th International Quenching and Control of Distortion Conference, Including the 4th International Distortion Engineering Conference, 2012, s. 858-866Konferensbidrag (Refereegranskat)
    Abstract [en]

    Straightening of components after heat treatment is a common procedure in the industry. Typically, elongated components such as shafts and bars are distorted after heat treatment in such a way that straightening is necessary to obtain the desired shape. The straightening operation leads to local plasticisation of the component. This has an effect on for example the residual stress state and the hardness, parameters with strong influence on the fatigue strength of the component. The objective has been to evaluate the influence of straightening on bending fatigue properties, the residual stress state, microstructure and hardness of induction hardened test bars. Straightening was made using three point bending on cylindrical shafts. The residual stress state and hardness were evaluated, before and after straightening. Fatigue testing was performed in three point bending, after rotating the shaft 60 ° after straightening, i.e. towards 120° direction. FEM-simulation of straightening was performed in order to formulate guidelines for straightening. The simulations were performed on a virtually induction hardened shaft of the same dimensions as used in the experiments. It was concluded that straightening affects the residual stress state along the entire circumference of a component. The fatigue strength at 120° was 7% lower after straightening with 80 kN load and 20% lower after straightening with 97 kN load. Residual stresses were affected differently around the perimeter of the shaft. At the point of straightening force application (0°) the compressive residual stresses after heat treating turned to tensile. At the opposite side at 180° the residual stresses turned more compressive than before straightening. At 120° and 240°, the stresses were negatively affected and the residual stresses turned less compressive. The higher of the two straightening forces had even more negative effect on residual stresses. The simulations showed similar changes in residual stresses as were experimentally found. It was concluded that reversed straightening should be avoided and that at higher forces used with combined straightening operations at an angle compared to the desired straightening direction is preferable if larger corrections needs to be done. Copyright © 2012 ASM International® All rights reserved.

  • 127.
    Haglund, Sven
    RISE, Swerea, Swerea KIMAB AB.
    Modelling and prediction of fatigue properties of tool steels based on defects, geometry and surface condition2010Ingår i: Proceedings of the World Powder Metallurgy Congress and Exhibition, World PM 2010, European Powder Metallurgy Association (EPMA) , 2010, Vol. 3Konferensbidrag (Refereegranskat)
    Abstract [en]

    During a period of the last ten years a new model has been developed at SwereaKIMAB that is able to predict the fatigue properties of tool steels based on measured carbide and inclusion distributions. The model has been programmed into software named FATSIMR. Lately, effects such as notch effect and surface roughness have been added to the model enabling it to predict the fatigue properties of actual tool designs. In the presence of a notch the software takes into account the decrease in stressed volume and thereby the decreased probability of a defect present in the most stressed part. As an upper bound the software estimates the intrinsic fatigue strength of the steel matrix. In this presentation the model is presented and examples are given on how the software can be applied on various high stressed tooling components.

  • 128.
    Haglund, Sven
    RISE, Swerea, Swerea KIMAB AB.
    Predicting residual stresses and hardness of a critical component using a combination of numerical and empirical methods2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes the experiences gained when using numerical and empirical methods in order to predict the accumulated surface characteristics for a safety component after several forging steps, controlled cooling and blasting. The forging steps were simulated in a sequence using one Finite Element (FE) code. The output forging mesh was used as input to the cooling simulation but was too coarse in order to reflect surface characteristics. The decarburisation effect during cooling that may influence the surface characteristics was not included in the cooling model. An attempt to create a parametric model of the blasting machine with output residual stresses and hardness as a function of input residual stresses, hardness and process parameters indicated the need of further investigation concerning the physical phenomena during blasting in the machine. A new method was developed for analysing the influence of the blasted surface texture on the stress intensity. The measured residual stresses and hardness span caused by variations in the blasting process were successfully used together with the stress intensity factor as input to a fatigue strength analysis. In order to establish a seamless chain of models through the manufacturing sequence further development concerning cooling and blasting models is required. © 2008 Verlag Stahleisen GmbH, Düsseldorf.

  • 129.
    Haglund, Sven
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Properties and performance of nitrided and nitrocarburized steels2014Ingår i: Proceedings - European Conference on Heat Treatment and 21st IFHTSE Congress / [ed] Lubben T.Zoch H.-W.Schneider R., Arbeitsgemeineschaft Warmebehandlung u. Werkstofftechnik , 2014, s. 29-36Konferensbidrag (Refereegranskat)
    Abstract [en]

    By utilizing nitriding processes in combination with selection of steel grade manufacturing of components with low friction and high wear properties is facilitated. The need for post machining and straightening is reduced as a consequence of low distortions due to the low process temperature. Nitriding and nitrocarburizing of a wide range of steel grades have been applied in order to evaluate influences on compound layer, diffusion zone and residual stresses and consequently the overall impact on fatigue and tribological properties. Demonstrator components, e.g. gear wheels, have been selected and measures to replace carburizing with nitriding processes. The level of distortion is greater for case hardened gear wheels compared to nitrided wheels. Furthermore, there seems to be less scattering in distortion level between the nitrided wheels within a given steel grade, suggesting that the distortions would be easier to predict and compensate for compared to case hardened wheels. The influence of steel and nitriding process was evaluated by wear testing. In lubricated conditions the tribological properties were quite similar for all tested samples. The result in dry conditions resulted in a lower friction at lower loads for some of the nitrided and/or nitrocarburized steels compared to case hardened steel 16MnCr5.

  • 130.
    Haglund, Sven
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Haglund, Sven
    RISE, Swerea, Swerea KIMAB AB.
    Temperature dependent material properties of Ruukki steel 1 used for quenching simulations2013Rapport (Refereegranskat)
    Abstract [en]

    This is a part report in the Swerea KIMAB AB project 222009 Modflat. The experimental result presented here can be used as materials data for the FEM software Sysweld where the quenching operation is simulated. In this work thermal and metallurgical properties and temperature dependent mechanical strengths has been determined for the Ruukki material here called Steel 1 with a thickness of 10 mm. The metallurgical properties that have been determined are heat conductivity (measured up to 500°C), enthalpy per phase (calculated by ThermoCalc), thermal expansion (measured by dilatometer), volume changes during phase transformation (measured by dilatometer) The mechanical properties that have been determined are Young’s modulus, yield stress and deformation hardening for different structures at different temperatures. The mechanical properties were measured by hot tensile tests and compressions tests. Sysweld is used as simulation software for the quenching simulations and consequently the material properties that are presented on a format that is easily implemented in Sysweld. The material properties are divided into the hot rolled structure, the austenitic phase and the martensitic structure.

  • 131.
    Haglund, Sven
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Haglund, Sven
    RISE, Swerea, Swerea KIMAB AB.
    Kristoffersen, Hans
    Fällström, Mikael
    Interrupted quenching during the martensite transformation in steels 100CrMn6 and 20NiCrMo72011Rapport (Refereegranskat)
    Abstract [en]

    In this work the hypothesis “All quenching of steel components should be interrupted at ~50% martensite formed in order to achieve better fatigue performance” has been tested. The results are very positive. The effect of slower quenching seems to be generic, i.e. valid for different steels and different heat treating processes. It has now been studied on three steels, three heat treatment methods and three quenching method (in this and previous projects) and it can be concluded that in all cases slower quenching gave better fatigue resistance when no HTTPstructures were formed in the surface. HTTP-structures are believed to act as a low strength skin neutralising the increased fatigue resistance from slow cooling. One important fact that brings us to the conclusion that the effect is generic was that in all cases dilatometer measurements with slower cooling gave less expansion during the martensite transformation, indicating more retained austenite, which would explain the better fatigue resistance by crack arrest from expansion of transforming retained austenite during fatigue. EBSD measurements have shown that the martensite laths were larger in the slower cooled samples and indicate more retained austenite in slower cooled samples. No difference in retained austenite content could be measured by x-ray, not on the fatigue test bars or in the dilatometer test bars. The measurement error in the x-ray method is likely to be too large to resolve the smalldifferences between different coolingrats. The effect of slow cooling on residualstresses remains unexplained. Smallerdilation during phase transformation inthe surface is thought to yield lowercompressive stresses, not higher asmeasured on the test bars.

  • 132.
    Haglund, Sven
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Kristoffersen, H.
    RISE, Swerea, Swerea IVF AB.
    Simulation of residual stresses after straightening of induction hardened components2014Ingår i: HTM - Journal of Heat Treatment and Materials, ISSN 18672493, Vol. 69, nr 3, s. 165-172Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Straightening is a manufacturing process where a component is bent, and plastically deformed, in order to reach a desired straightness. It is an unwanted but in many cases necessary process. For instance heat treatment operations such as carburizing and induction hardening may give distortions of magnitude that a straightening operation is required. The main disadvantage with straightening, apart from the extra processing step, is that it alters the residual stresses which decrease the fatigue strength of the component. In this paper, the straightening of a surface hardened shaft is simulated by FEM. The paper brings new insight into the complexity in the changes in residual stress that deviates far from the simplified views presented in literature. It will be shown that there are fundamental differences between a through hardened shaft and a surface hardened one as well as between shafts with shallow and deep surface hardening depths. The material studied is 42CrMo4 induction hardened by single shot. It is shown that the change in residual stresses is rather complex with decreased compressive residual stresses in a number of locations around the circumference while other locations have increased stresses. The amount of change in the residual stresses are largely governed by the required bending but by doing the straightening operation in an optimal way the negative effect can be reduced. © 2014 Carl Hanser Verlag GmbH & Co. KG.

  • 133.
    Hammam, Tag
    RISE, Swerea, Swerea KIMAB AB.
    High temperature SiC packaging – a literature review and outlines of new concepts2012Rapport (Refereegranskat)
    Abstract [en]

    The introduction of SiC power devices for automotive applications requires new design of the module in order to utilise the full erformance. The commercial SiC components available today utilises package designs originally developed for silicon components, e.g. the Direct Bonded Copper (DBC) concept, where the SiC die is bonded to a copper plated ceramic insulator. However, the reliability during thermal cycling needs to be improved due a higher operating temperature. The thermal management needs also be improved due to a smaller chip area for the SiC die (approximately 30 % of the silicon a die). The reliability during thermal cycling can be improved by replacing the solder bond with e.g a sintered layer of a submicron silver paste, or an Ag foil. In the DBC concept the main thermal resistances is caused by the heat spreader and the interfacial thermal resistance between the heat spreader and the heat sink. In this study, three new concepts of the SiC die/heat spreader are proposed. In all of the proposed concepts, a silver coated molybdenum disc or a silver coated super soft copper disc is in between the SiC die and the heat spreader. The proposed concepts are: 1. The SiC die is mounted at the edge of the heat spreader, and the heat spreader is clamped between wo heat sinks. The applied interfacial pressure between the heat sinks and the heat spreader can be very high, due to that the SiC die is not subjected to the clamping pressre. This results in a low interfacial thermal resistance between the heat spreader and the heat sink. 2.The SiC device directly mounted on a heat spreader with electrically insulated water channels. Quick water couplings can be used to facilitate mounting and demounting. 3.The SiC die is placed perpendicular to the surface of the heat sink, and the SiC die is clamped in between two large heat spreaders. The design enables a very precise clamping force to be applied on the SiC die by using e.g. spring loaded brackets or clamps. The applied interfacial pressure between the heat sinks and the heat spreader can be very high, due to that the SiC die is not subjected to the clamping pressure.

  • 134.
    Han, J.
    et al.
    PSL Research University, France.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Ogle, K.
    PSL Research University, France.
    Temperature dependence of the passivation and dissolution of Al, Zn, and α-phase Zn-68Al2019Ingår i: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 75, nr 1, s. 69-79Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The reactivity of the α-phase of Al-Zn (Zn-68 wt% Al, Al 5.2 Zn) in deaerated 0.1 M NaOH solution (simulating industrial pretreatments) was investigated and compared with that of pure Al and Zn. The elementary phenomena of metal oxidation, dissolution, oxide formation, and hydrogen evolution were decoupled using atomic emission spectroelectrochemistry. At the open-circuit potential, the Al 5.2 Zn phase reacted similarly as pure Al, undergoing selective Al dissolution to form a Zn(0) enriched layer. The Zn in the alloy shifted the potential to just below the onset of Zn dissolution. Elementary polarization curves showed that Zn dissolution was similar for the Al 5.2 Zn phase as for pure Zn. Near the open-circuit potential, Zn dissolution was faradaic limited by the formation of surface Zn(OH) 2 . At higher temperature, significant amounts of ZnO formed resulting in passivation. For the Al 5.2 Zn phase, the rates of Al and Zn dissolution were determined by a charge transfer mechanism across the ZnO film. Kinetic parameters (activation energies and Tafel slopes) were measured for some of the elementary processes. 

  • 135.
    Han, Tong
    et al.
    KTH Royal Institute of Technology, Sweden.
    Sophonrat, Nanta
    KTH Royal Institute of Technology, Sweden.
    Tagami, Ayumu
    KTH Royal Institute of Technology, Sweden ; Nippon Paper Industries Co., Japan.
    Sevastyanova, Olena
    KTH Royal Institute of Technology, Sweden.
    Mellin, Pelle
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Yang, Weihong
    KTH Royal Institute of Technology, Sweden.
    Characterization of lignin at pre-pyrolysis temperature to investigate its melting problem2019Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 235, s. 1061-1069Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Technical lignin particles melt under relatively low temperature. This results in the problem in the continuous feeding and fluidization during lignin pyrolysis, which in turn limits its utilization on a large scale. In this study, two most available types of lignin have been used to investigate the lignin melting problem, which are Kraft lignin (KL) from pulping process and hydrolysis lignin (HL) from bio-ethanol production process. Elemental composition, thermal property and thermally decomposed derivatives of each sample are tested by elemental analyzer, TGA, DSC, and Py-GC/MS. Morphology, structure and crystal change before and after heat treatment are tested by microscopy, FTIR and XRD. All results suggest that lignin structure determines its melting properties. Kraft lignin from pulping process contains a less cross-linked structure. It melts under heating. On the other hand, hydrolysis lignin from hydrolysis process contains a highly crossed-linked and condensed structure. It does not melt before decomposition under heat treatment. Modifying lignin structure is suggested for the resolution of technical lignin melting problem.

  • 136.
    Hedberg, Jonas F.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Le Bozec, Nathalie
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Odnevall Wallinder, Inger
    KTH Royal Institute of Technology, Sweden.
    Spatial distribution and formation of corrosion products in relation to zinc release for zinc sheet and coated pre-weathered zinc at an urban and a marine atmospheric condition2013Ingår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 64, nr 4, s. 300-308Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zinc release data from 5 years of unsheltered exposures in a marine and an urban site is compiled for different zinc material types. The thin surface treatment on zinc materials is gradually detached after approximately 2 years at both sites, revealing the pre-weathered zinc surface unprotected. This consequently increased the release rates of zinc from this surface, whereas the zinc runoff rate from the bare zinc sheet remained relatively stable. Raman studies on bare zinc sheet exposed for 5 years at the marine site revealed zinc oxide of varying crystalline nature and hydrozincite to appear localized and separated from each other.

  • 137.
    Hedberg, Y.
    et al.
    Royal Institute of Technology (KTH).
    Karlsson, Oskar
    RISE, Swerea, Swerea KIMAB AB.
    Szakalos, P.
    Royal Institute of Technology (KTH).
    Wallinder, I.O.
    Royal Institute of Technology (KTH).
    Ultrafine 316 L stainless steel particles with frozen-in magnetic structures characterized by means of electron backscattered diffraction2011Ingår i: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 65, nr 14, s. 2089-2092Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electron Backscatter Diffraction (EBSD) studies clearly revealed a different crystallographic structure of the smallest particle size fraction of gas-atomized AISI 316 L stainless steel powder (< 4 μm) compared with larger sized fractions of the same powder (< 45 μm). Despite similar chemical compositions, the predominating structure of the smallest particle size fraction was ferritic (i.e., has ferromagnetic properties) whereas the larger sized particle fractions and massive 316 L revealed an expected austenitic and non-magnetic structure. From these findings, it follows that direct magnetic separation can be applied to separate very fine sized particles. These structural differences explain previously observed dissimilarities from corrosion and metal release perspectives. © 2011 Elsevier B.V. All rights reserved.

  • 138.
    Hedegård, Joakim
    RISE, Swerea, Swerea KIMAB AB.
    Avoiding porosity and spatter in hot-dip galvanized C-Mn steels by laser twin-spot welding2010Ingår i: Proc. of the Int. Conf. on Advances in Welding Science and Technology for Construction, Energy and Transportation, AWST 2010, held in Conj. with the 63rd Annual Assembly of IIW 2010, 2010, s. 325-329Konferensbidrag (Refereegranskat)
    Abstract [en]

    During welding of zinc-coated materials, zinc trapped in the overlap of a lap joint expands violently because of vaporization, and therefore disturbs the laser keyhole. Laser twin-spot welding is a new approach for welding of thin sheet C-Mn steel. The dual beam principle creates a larger and more stabilized weld pool. Therefore welding of galvanized zero gap lap joints becomes possible. This opens a new joining approach for automotive and other industries to perform high speed laser welding. The possibility to laser weld steels with 20 μm zinc coating thickness with high speed and high quality is a technical breakthrough.

  • 139.
    Hedegård, Joakim
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Nerman, Peter
    RISE, Swerea, Swerea KIMAB AB.
    Wahlsten, Joakim
    RISE, Swerea, Swerea KIMAB AB.
    Randelius, Mats
    RISE, Swerea, Swerea KIMAB AB.
    Larsson, Mats
    RISE, Swerea, Swerea KIMAB AB.
    Influence of internal microfissures on fatigue life2009Ingår i: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 53, s. R209-R220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of microfissures on the fatigue strength of submerged arc weids in two high-alloyed, austenitic stainless steels has been studied. It was shown that internal microfissures in the weld metal can have a significant influence on the fatigue strength of the joint when the weld geometry is omitted (machined flat).. Still, all test series showed good fatigue performance and reached better results than expected. Three of the four fatigue series reached a loading capacity close to Rp0.2 for the base metal and one of the series reached levels close to Rp0.2 for the weld metal.

  • 140.
    Hedström, P.
    et al.
    KTH Royal Institute of Technology.
    Huyan, F.
    KTH Royal Institute of Technology.
    Zhou, J.
    KTH Royal Institute of Technology.
    Wessman, Sten
    RISE, Swerea, Swerea KIMAB AB.
    Thuvander, M.
    Chalmers University of Technology.
    Odqvist, J.
    KTH Royal Institute of Technology.
    The 475°C embrittlement in Fe-20Cr and Fe-20Cr-X (X=Ni, Cu, Mn) alloys studied by mechanical testing and atom probe tomography2013Ingår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 574, s. 123-129Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work the 475 °C embrittlement in binary Fe-Cr and ternary Fe-Cr-X (X=Ni, Cu and Mn) alloys have been investigated. The mechanical properties were evaluated using microhardness and impact testing, and the structural evolution was evaluated using atom probe tomography (APT). The APT results after aging at 500 °C for 10. h clearly showed that both Ni and Mn accelerate the ferrite decomposition. No evident phase separation of either the Fe-20Cr or Fe-20Cr-1.5Cu samples was detected after 10. h of aging and thus no conclusions on the effect of Cu can be drawn. Cu clustering was however found in the Fe-20Cr-1.5Cu sample after 10. h aging at 500 °C. The mechanical property evolution was consistent with the structural evolution found from APT. Samples aged at 450 and 500 °C all showed increasing hardness and decreasing impact energy. The embrittlement was observed to take place mainly during the first 10. h of aging and it could primarily be attributed to phase separation, but also substitutional solute clustering and possibly carbon and nitrogen segregation may contribute in a negative way. © 2013 Elsevier B.V.

  • 141.
    Hertzman, Staffan
    RISE, Swerea, Swerea KIMAB AB.
    A study of duplex stainless steels aged at 325°C under applied tensile load2011Ingår i: 7th European Stainless Steel Conference: Science and Market, Proceedings, Associazione Italiana di Metallurgia , 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Duplex stainless steels (DSS) are widely used due to their good combination of corrosion resistance and mechanical properties. The embrittlement caused by phase separation of ferrite in DSS, however, limits the maximum service temperature. Since weldments have been considered most sensitive it has been speculated whether weld residual stresses contribute to the kinetics of phase separation. A mechanistic study was performed on commercial DSS materials of different alloying levels. Specimens were aged under load and the mechanical properties in terms of hardness and impact toughness were determined. Also weld structures and simulated HAZ structures were tested. Differences in response were observed for the different microstructures, which were characterized by EBSD and TEM. The decomposition was characterized using atom probe tomography and the results seem to support the effect of stress on kinetics.

  • 142.
    Hervestad, Eleonora
    RISE, Swerea, Swerea KIMAB AB.
    A new methodology for nitride characterisation in stainless steels, and its application on duplex 2205 and superduplex 25072012Rapport (Refereegranskat)
    Abstract [en]

    Duplex and superduplex stainless steel, 2205 and 2507, have been examined with the aim of finding a methodology for nitride characterisation. LOM, SEM/STEM (SED, BSED, TED) and TEM (STEM) were used extensively for microscopy investigations to characterise microstructures and nitride contents. 2507 was heat treated for 10 minutes at 1050°C, 1100°C, 1150°C and also one longer heat treatment for 7 days at 1100°C. This longer treatment also included 2205. The purpose of the 7 days heat treatment was to achieve a larger austenite spacing and thus higher probability for nitride precipitation. Hexagonal chromium nitrides, Cr2N, were found in all specimens. Higher heat treatment temperatures and longer heat treatment times gave larger areas of ferrite and consequently more nitrides. The nitrides were needle shaped and seemed to be constituted as a mixture of two populations, one with larger and one with smaller nitrides. The nitride precipitates were found in the centre of the ferrite grains and they seem to form with a certain orientation relation towards the ferrite matrix.

  • 143.
    Hervestad, Eleonora
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Frisk, Karin
    RISE, Swerea, Swerea KIMAB AB.
    Tool Steels, Phases and Alloying Elements, Literature survey2014Rapport (Refereegranskat)
    Abstract [en]

    This report is meant to give a brief introduction to tool steels, phases and alloying elements. The focus is to understand the microstructure, its evolution and how it is altered through processing, heat treatment and alloying. The first part of the report gives a general insight into tool steels, some example of the major tool steels groups and processing. The second part of the report concentrates on the phases that can appear in tool steels. Some phases are given more attention than others depending on regular appearance and level of interest. The last part of the report concerns alloying elements and give an overview of elements and their properties. In the very end a summary of the outcome is given.

  • 144.
    Hokka, Mikko
    et al.
    Tampere University of Technology, Finland.
    Rämö, Jari
    Tampere University of Technology, Finland.
    Mardoukhi, Ahmad
    Tampere University of Technology, Finland.
    Vuoristo, Taina
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Roth, Armin
    Schmolz+Bichenbach Group CREAS, France.
    Kuokkala, Veli Tapani
    Tampere University of Technology, Finland.
    Effects of Microstructure on the Dynamic Strain Aging in Ferritic-Pearlitic Steels2018Ingår i: Journal of Dynamic Behavior of Materials, ISSN 2199-7446, Vol. 4, nr 4, s. 452-463Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Effects of microstructure on the high strain rate high temperature mechanical response and dynamic strain aging of C45 and 27MnCr5 ferritic-pearlitic steels were studied using four different microstructural variants of the standard alloys. The high strain rate high temperature behavior of the steels was studied using a compression Split Hopkinson Pressure Bar device with high temperature testing capabilities. The steels were studied at strain rates up to 4500 s−1 and at temperatures from RT to 680 °C. Strong dynamic strain aging was observed for both steels in the studied temperature range. The results also show that the microstructure has a strong effect on the dynamic strain aging sensitivity of the steel. This is especially true at low plastic strains, where the effect of the microstructure is strongest. The effect of microstructure decreases as plastic strain increases. A coarse-grained microstructure showed the strongest dynamic strain aging sensitivity for both steels.

  • 145.
    Hoseini, Saba
    RISE, Swerea, Swerea KIMAB AB.
    Experimental simulation of gear hobbing through a face milling concept in CNCmachine2013Rapport (Refereegranskat)
    Abstract [en]

    High-speed steels are the main material for cutting tools especially for producing gear boxes in the automotive industry. Cutting performance of high speed steel depends on their resistance to wear, their toughness and resistance to tempering at operating temperature. In this project, tool-life and wear type of cutting tools made of powder metallurgy high speed steel (PM-HSS) were investigated up to a flank wear width of 0.30 mm in different steels and cutting speeds. Hardness and cutting speed had a significant effect on tool-wear, tool-life and chip formation. More rake face wear was occurred by harder materials because of higher thermomechanical loading .Three indicators were used for representing tool life and to show the relation of cutting speed and hardness with cutting performance. Difference of tool life between the softest and the hardest steels was about two times. By increasing cutting speed in every work-material more number of passes was obtained. The required data were obtained experimentally by a 3-axis milling machine. This test method facilitates simulation of gear hobbing wear type in a less time-consuming way, compared to the other methods which have the same kinematics of real hobbing.

  • 146.
    Hosseini, Vahid. A.
    et al.
    University West, Sweden ; Innovatum AB, Sweden.
    Karlsson, Leif
    University West, Sweden.
    Wessman, Sten
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB. University West, Sweden.
    Fuertes, Nuria
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Effect of sigma phase morphology on the degradation of properties in a super duplex stainless steel2018Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 11, nr 6, artikel-id 933Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sigma phase is commonly considered to be the most deleterious secondary phase precipitating in duplex stainless steels, as it results in an extreme reduction of corrosion resistance and toughness. Previous studies have mainly focused on the kinetics of sigma phase precipitation and influences on properties and only a few works have studied the morphology of sigma phase and its influences on material properties. Therefore, the influence of sigma phase morphology on the degradation of corrosion resistance and mechanical properties of 2507 super duplex stainless steel (SDSS) was studied after 10 h of arc heat treatment using optical and scanning electron microscopy, electron backscattered diffraction analysis, corrosion testing, and thermodynamic calculations. A stationary arc was applied on the 2507 SDSS disc mounted on a water-cooled chamber, producing a steady-state temperature gradient covering the entire temperature range from room temperature to the melting point. Sigma phase was the major intermetallic precipitating between 630 °C and 1010 °C and its morphology changed from blocky to fine coral-shaped with decreasing aging temperature. At the same time, the average thickness of the precipitates decreased from 2.9 μm to 0.5 μm. The chemical composition of sigma was similar to that predicted by thermodynamic calculations when formed at 800-900 °C, but deviated at higher and lower temperatures. The formation of blocky sigma phase introduced local strain in the bulk of the primary austenite grains. However, the local strain was most pronounced in the secondary austenite grains next to the coral-shaped sigma phase precipitating at lower temperatures. Microstructures with blocky and coral-shaped sigma phase particles were prone to develop microscale cracks and local corrosion, respectively. Local corrosion occurred primarily in ferrite and in secondary austenite, which was predicted by thermodynamic calculations to have a low pitting resistance equivalent. To conclude, the influence of sigma phase morphology on the degradation of properties was summarized in two diagrams as functions of the level of static load and the severity of the corrosive environment.

  • 147.
    Hosseini, Vahid
    et al.
    University West, Sweden; Innovatum AB, Sweden.
    Hurtig, Kjell
    University West, Sweden.
    Eyzop, Daniel
    Outokumpu Stainless AB, Sweden.
    Östberg, Agneta
    Sandvik Materials Technology, Sweden.
    Janiak, Paul
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Karlsson, Leif
    University West, Sweden.
    Ferrite content measurement in super duplex stainless steel welds2019Ingår i: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 63, nr 2, s. 551-563Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Approaches to determining ferrite fraction (%) and ferrite number (FN) were examined for super duplex stainless steel (SDSS) welds. A reference sample was produced by bead-on-plate gas–tungsten arc welding of a type-2507 SDSS plate. By comparing different etchants and measurement practices, it was realized that etching with modified Beraha followed by computerized image analysis (IA) was the most accurate and quickest technique to measure ferrite fraction, which determined the same ferrite fraction (68.0 ± 2.6%) as that measured by electron diffraction backscattered analysis (67.6 ± 2.3%). A Round Robin test was performed on a reference sample at University West, Swerea KIMAB, Outokumpu Stainless, and Sandvik Materials Technology to investigate the repeatability of the technique. The ferrite fraction measurements performed at different laboratories showed very small variations, which were in the range of those seen when changing microscope in the same laboratory. After verification of the technique, the relationship between ferrite fraction and ferrite number (measured with FERITSCOPE®) was determined using 14 single (root) pass welds, including butt, corner, and T-, V-, and double V-joint geometries. The best-fit equation found in this study was ferrite number (FN) = 1.1 × ferrite fraction (%). To conclude, the ferrite fraction technique suggested in the present paper was accurate and repeatable, which made it possible to determine a ferrite fraction–ferrite number formula for SDSS single-pass welds.

  • 148.
    Houlle, Patrice
    et al.
    Haynes International, France.
    Larche, Nicolas
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Cassagne, Thierry B.
    Total CSTJF, France.
    Zuili, Delphine
    Technip France, France.
    Bluzat, Pascal
    GEA Ecoflex, France.
    Behavior of some Ni-base alloys and stainless steel in plate heat exchanger conditions using chlorinated sea water2009Ingår i: European Corrosion Congress 2009, EUROCORR 2009, 2009, s. 2539-2551Konferensbidrag (Refereegranskat)
    Abstract [en]

    Many oil and gas offshore facilities use heat exchangers cooled with seawater. Titanium is widely used for seawater plate heat exchangers, but its availability for this market depends on other large demand from other markets like the aerospace industry. Thus, it is vital to find alternative materials in seawater heat exchangers' applications. High-alloyed stainless steels and nickel-base alloys are used for different marine and offshore applications, but have not been widely used for seawater plate heat exchangers. Most of the corrosion data available in the literature on these alloys have been obtained from laboratory experiments. Thus, there is a need to determine the corrosion resistance of these alloys under real service conditions. This is important as heat transfer, flowing and geometrical conditions of plate heat exchangers may be difficult to simulate based upon simple laboratory exposure. Therefore, a test program has been developed to test selected materials in actual plate heat exchanger conditions using natural sea water during one year and more. These materials are nickel-based alloys UNS N06625, N10276, N06059, N06200 and N06686, along with a special steel UNS N08031. The study was performed in chlorinated natural sea water from 30°C up to 60°C. The result data from this test program are presented and discussed in this paper.

  • 149.
    Hutchinson, Bevek
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Komenda, Jacek
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Observations of dynamic transformation products in a commercially hot-rolled steel2018Ingår i: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 34, nr 10, s. 2297-1200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sufficient evidence has now accumulated to show that dynamic transformation (DT) is a real phenomenon in steels and can take place over a wide range of temperatures in the austenite regime. During plastic deformation, some of the austenite is transformed to ferrite despite austenite being the chemically more stable equilibrium phase. Occurrence of DT has been demonstrated in various laboratory tests but apparently not in commercially hot-rolled steels. In this note, we review some old results on high strength low alloy strip steel that contained microstructural features that appear to have been caused by DT. We deduce that DT occurred early in the rolling schedule, leading to thin-pancaked sheets of ferrite in the final product. The presence of these pre-existing ferrite nuclei frequently gave rise to adjacent regions of coarse polygonal ferrite grains during cooling.

  • 150.
    Hutchinson, Bevek
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Martin, D.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Karlsson, Oskar
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Lindberg, F.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Thoors, H.
    RISE - Research Institutes of Sweden, Material och produktion, KIMAB.
    Marceau, R. K. W.
    Deakin University, Australia.
    Taylor, A. S.
    Deakin University, Australia.
    Vanadium microalloying for ultra-high strength steel sheet treated by hot-dip metallising2017Ingår i: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 33, nr 4, s. 497-506Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ultra-high strength steel sheets have been subjected to heat treatments that simulate the thermal cycles in hot-dip galvanising and galvannealing processes and evaluated with respect to their resulting mechanical properties and microstructures. The steels contained suitable contents of carbon (∼0.2%), manganese (1.2%) and chromium (0.4%) to ensure that they could be fully transformed to martensite after austenitisation followed by rapid cooling in a continuous annealing line, prior to galvanising. Different contents of vanadium (0–0.1%) and nitrogen (0.002–0.012%) were used to investigate the possible role of these microalloying elements on the strength of the tempered martensite. Vanadium, especially when in combination with a raised nitrogen content, helps to resist the effect of tempering so that a larger proportion of the initial strengthening is preserved after the galvanising cycle, giving tensile strength levels exceeding 1000 MPa. Different deoxidation practices using aluminium or silicon have also been included. These showed similar strength levels at corresponding carbon contents but the bendability of the Si-killed steel sheet was considerably superior. Microstructural examinations have been made on the annealed steels but the reason for the beneficial effect of vanadium is still not fully explained. It is concluded that microalloying with vanadium is a very promising approach in the development of corrosion-resistant ultra-high strength steel sheet products.

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