Change search
Refine search result
12 1 - 50 of 70
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Ahlström, Johan
    et al.
    RISE, Swerea, KIMAB.
    Tidblad, Johan
    RISE, Swerea, KIMAB. RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Sederholm, Bror
    RISE, Swerea, KIMAB.
    Wadsö, L.
    Lund University, Sweden.
    Influence of chloride and moisture content on steel rebar corrosion in concrete2016In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 67, no 10, p. 1049-1058Article in journal (Refereed)
    Abstract [en]

    Reinforced mortar samples were exposed in humidity chambers with different relative humidity or exposed in cyclic moisture conditions. The rebars were in an “as received” condition meaning that the preexisting oxide scale were intact. The lowest chloride concentration that initiated corrosion was 1% Cl− by mass of cement, corrosion was then observed for samples exposed at 97% relative humidity. It is suggested that the corrosion rate decreases when samples are exposed to a relative humidity lower than 97%. The results indicate that threshold levels should be evaluated at rather humid conditions (97%) despite the fact that the maximum corrosion rate at higher chloride levels is observed in the interval 91–94%. For samples exposed to cyclic moisture conditions, a lower chloride concentration was needed to initiate corrosion compared to samples exposed in static moisture conditions.

  • 2.
    Alipour, Y.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Viklund, Peter
    RISE, Swerea, KIMAB.
    Henderson, P.
    Vattenfall, Sweden.
    The analysis of furnace wall deposits in a low-NOx waste wood-fired bubbling fluidised bed boiler2012In: VGB PowerTech, ISSN 1435-3199, Vol. 92, no 12, p. 96-100Article in journal (Refereed)
    Abstract [en]

    Increasing use is being made of biomass as fuel for electricity production as the price of natural wood continues to rise. Therefore, more use is being made of waste wood (recycled wood). However, waste wood contains more chlorine, zinc and lead, which are believed to increase corrosion rates. Corrosion problems have occurred on the furnace walls of a fluidised bed boiler firing 100 % waste wood under low-NOx conditions. The deposits have been collected and analysed in order to understand the impact of the fuel.

  • 3.
    Andersson, J.
    et al.
    RISE, Swerea, KIMAB.
    Persson, Daniel
    RISE, Swerea, KIMAB.
    Jönsson, D.
    Scania CV, Sweden.
    Tornberg, Malin
    RISE, Swerea, KIMAB.
    Lindh-Ulmgren, Eva
    RISE, Swerea, KIMAB.
    Degradation of carbon fiber reinforced composites induced by galvanic coupling to metallic materials2015In: European Corrosion Congress, EUROCORR 2015, Austrian Society for Metallurgy and Materials (ASMET) , 2015Conference paper (Refereed)
  • 4.
    Andersson, O.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Semere, D.
    KTH Royal Institute of Technology, Sweden.
    Melander, Arne
    RISE, Swerea, KIMAB. KTH Royal Institute of Technology, Sweden.
    Arvidsson, M.
    Volvo Car Corporation, Sweden.
    Lindberg, B.
    KTH Royal Institute of Technology, Sweden.
    Digitalization of Process Planning of Spot Welding in Body-in-white2016In: Procedia CIRP, Elsevier B.V. , 2016, p. 618-623Conference paper (Refereed)
    Abstract [en]

    Process planning of spot welding for body-in-white automobile structures involves several experimental (physical) welding trials to set the process parameters. These experimental trials are crucial in ensuring the quality and efficiency of the process. However, due to the iterative nature of the work, running several experiments is costly and time consuming prolonging the overall development cost and time significantly. To minimize the cost and time, replacing the physical tests by digital (virtual) tests is an established approach although not often applied for spot welding. However, for a long chain of development process with several iterative loops, this is not a trivial task considering the availability of information and continuity of the work flow. This paper reports the work and results of an industrial case study conducted on spot welding of a body-in-white car pillar in a Swedish auto manufacturer. The aim of the study is to investigate and propose the necessary conditions required to replace a physical test by virtual tests in terms of validity and expedited execution of the process. Information sharing, knowledge reuse and streamlining the work flow have found to be critical condition for valid and rapid virtual tests. © 2016 The Authors.

  • 5.
    Ankerfors, Caroline
    et al.
    RISE, Swerea, KIMAB.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Polyelectrolyte complexes for tailoring of wood fibre surfaces2014In: Advances in Polymer Science, ISSN 0065-3195, E-ISSN 1436-5030, Vol. 256, p. 1-24Article in journal (Refereed)
    Abstract [en]

    The use of polyelectrolyte complexes (PECs) provides new opportunities for surface engineering of solid particles in aqueous environments to functionalize the solids either for use in interactive products or to tailor their adhesive interactions in the dry and/or wet state. This chapter describes the use of PECs in paper-making applications where the PECs are used for tailoring the surfaces of wood-based fibres. Initially a detailed description of the adsorption process is given, in more general terms, and in this respect both in situ formed and pre-formed complexes are considered. When using in situ formed complexes, which were intentionally formed by the addition of oppositely charged polymers, it was established that the order of addition of the two polyelectrolytes was important, and by adding the polycation first a more extensive fibre flocculation was found. PECs can also form in situ by the interaction between polyelectrolytes added and polyelectrolytes already present in the fibre suspension originating from the wood material, e.g. lignosulphonates or hemicelluloses. In this respect the complexation can be detrimental for process efficiency and/or product quality depending on the charge balance between the components, and when using the PECs for fibre engineering it is not recommended to rely on in situ PEC formation. Instead the PECs should be pre-formed before addition to the fibres. The use of pre-formed PECs in the paper-making process is described as three sub-processes: PEC formation, adsorption onto surfaces, and the effect on the adhesion between surfaces. The addition of PECs, and adsorption to the fibres, prior to formation of the paper network structure has shown to result in a significant increase in joint strength between the fibres and to an increased strength of the paper made from the fibres. The increased joint strength between the fibres is due to both an increased molecular contact area between the fibres and an increased molecular adhesion. The increased paper strength is also a result of an increased number of fibre/fibre contacts/unit volume of the paper network. 

  • 6.
    Bengtson, Arne
    et al.
    RISE, Swerea, KIMAB.
    Hildebrand, L.
    Technical University of Dortmund, Germany.
    Expert systems for prediction of corrosion properities of Zn-based coatings from the chemical analysis2012In: Yejin Fenxi/Metallurgical Analysis, ISSN 1000-7571, Vol. 32, no 4, p. 1-5Article in journal (Refereed)
    Abstract [en]

    The purpose of the work is to develop a general method, to predict the corrosion resistance of Zn-based coatings, expressed as total mass loss in an accelerated salt spray test. The method is to be based on just three analytical parameters; the total coating weights of Zn, Al and Mg. The reason for this restriction is that determination of these three parameters is possible in on-line analysis. The predicted corrosion resistance could then be included in a process/quality control system. Accelerated corrosion tests have been carried out by Swerea KIMAB IC (Institut de Corrosion) in Brest, and CRM in Belgium. Test were run according to the Renault ECC1 test D172028/-C (12 weeks), and with an accelerated cyclic corrosion test developed by CRM. The materials were divided into four corrosion classes according to total mass loss. All corrosion experiments show clearly the well documented positive influence of magnesium and aluminium. In relation to the masses of these elements in the coatings, the influence of both elements is considerably higher than the influence of zinc alone. For this reason, a new quantity is introduced, called "equivalent Zn coating weight". This quantity is a linear combination of the coating weights of zinc, aluminium and magnesium. A model for prediction of corrosion resistance was developed with the expert system, based on a combination of regression analysis and a "decision tree" algorithm. The model was able to correctly classify 25 out of 27 materials based on just the three analytical parameters mentioned above: the total coating weights of zinc, aluminium and magnesium. In conclusion, the approach shows that an accurate prediction of the corrosion behaviour is possible even on-line. For purposes of material development, the expert system can also be expanded to include additional analytical parameters.

  • 7.
    Bengtson, Arne
    et al.
    RISE, Swerea, KIMAB.
    Sedlakova, Miroslva
    RISE, Swerea, KIMAB.
    Didriksson, R.
    SSAB, Sweden.
    Rapid inclusion characterisation by pulse distribution analysis optical emission spectroscopy-recent development2013In: Yejin Fenxi/Metallurgical Analysis, ISSN 1000-7571, Vol. 33, no 1, p. 7-12Article in journal (Refereed)
    Abstract [en]

    The purpose of the work is to further develop and validate the optical emission method pulse distribution analysis (PDA) for rapid inclusion characterisation in steel production. The experimental work was focused on investigation of several operational parameters: spark energy, spark frequency and time gating of signal acquisition. The results showed that a low spark energy improves the detection limit, but at the expense of measuring statistics due to a smaller sample volume. The measuring frequency proved to have no significant influence on the analytical results, but several existing instruments cannot handle the highest spark frequencies above about 300 Hz in PDA mode due to limitations in the electronics. Investigation of time gating (TRS) gave only a marginal improvement in the detection limit of Si outliers above the metallic content. The work also revealed that there is a risk to detect "false" outliers due to asymmetric intensity distributions. This has resulted in the development of more advanced algorithms for outlier detection, increasing the accuracy of the method. Another limitation found is that the particle number density must not exceed about 10 000 inclusions/mm3 for the method to effectively detect single inclusions. A method to overcome this limitation has been suggested, but not yet evaluated. The accuracy of quantitative determination of the Al content in inclusions has been verified by reference methods. In conclusion, it has been demonstrated that state-of-the-art PDA is a very powerful technique for rapid inclusion characterisation in steels. Furthermore, the speed of analysis is sufficiently high for process feedback and controllable.

  • 8.
    Carlson, J. E.
    et al.
    Luleå University of Technology, Sweden.
    Lundin, Peter
    RISE, Swerea, KIMAB.
    Measurement of the clamping force applied by load-bearing bolts using a combination of compression and shear ultrasonic waves2015In: 2015 IEEE International Ultrasonics Symposium, IUS 2015, Institute of Electrical and Electronics Engineers Inc. , 2015Conference paper (Refereed)
    Abstract [en]

    Quantitative measurement of the clamping or tightening force of rods and bolts is important when assessing the structural integrity of various constructions. This paper shows that by using a bi-wave ultrasonic pulse-echo technique, it is possible to determine this tightening force without the need of extensive calibration prior to installing the bolts. We show that the ratio of the time-of-flight (TOF) between the transversal and the longitudinal waves changes linearly with the clamping force and that we only need to know the TOF of the unstrained bolt prior to installment. This is then demonstrated experimentally on a 1.1 m rock bolt, using pulses that propagated 6.6 m. Two different methods for estimation of the TOF ratio are evaluated.

  • 9.
    Cedervall, Johan
    et al.
    Uppsala University, Sweden.
    Beran, Premysl
    Nuclear Physics Institute, Czech Republic.
    Vennström, Marie
    AB Sandvik, Sweden.
    Danielsson, Thererse
    Etteplan Sweden AB, Sweden.
    Ronneteg, Sabina
    AB Sandvik, Sweden.
    Höglin, Viktor
    Scienta Sauna Systems AB, Sweden.
    Lindell, David
    RISE, Swerea, KIMAB.
    Eriksson, Olle
    Uppsala University, Sweden.
    André, Gilles
    CEA-Saclay, France.
    Andersson, Yvonne
    Uppsala University, Sweden.
    Nordblad, Per
    Uppsala University, Sweden.
    Sahlberg, Martin
    Uppsala University, Sweden.
    Low temperature magneto-structural transitions in Mn3Ni20P62016In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 237, p. 343-348Article in journal (Refereed)
    Abstract [en]

    X-ray and neutron powder diffraction has been used to determine the crystal and magnetic structure of Mn3Ni20P6. The crystal structure can be described as cubic with space group Fm3¯m (225) without any nuclear phase transformation within studied temperature interval from room temperature down to 4 K. The magnetic structure of Mn3Ni20P6 is complex with two independent magnetic positions for the Mn atoms and the compound passes three successive magnetic phase transitions during cooling. At 30 K the spins of the Mn atoms on the Wyckoff 4a site (Mn1) order to form a primitive cubic antiferromagnetic structure with propagation vector k=(0 0 1). Between 29 and 26 K the Mn atoms on the Wyckoff 8c site (Mn2) order independently on already ordered Mn1 magnetic structure forming a commensurate antiferromagnetic structure with propagation vector k=(0 0 12) and below 26 K, both Mn positions order to form an incommensurate helical structure with propagation vector k=(0 0 ~0.45). Magnetization vs. temperature curve of Mn3Ni20P6 shows a steep increase indicating some magnetic ordering below 230 K and a sharp field dependent anomaly in a narrow temperature range around 30 K.

  • 10.
    Claesson, Erik
    et al.
    RISE, Swerea, KIMAB.
    Rod, Olivier
    RISE, Swerea, KIMAB.
    The effect of alloying elements on the corrosion resistance of brass2016In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 32, no 17, p. 1794-1803Article in journal (Refereed)
    Abstract [en]

    A systematic study has been performed on the effect of alloying elements arsenic (As), antimony (Sb) and phosphorus (P) on the dezincification resistance of α-phase in brass. The result showed that P formed particles with Al and Fe already at relatively high temperatures, leaving no P in solid solution and thus no protection against dezincification. Arsenic only formed particles at lower temperatures and offers a satisfactory protecting. However, with increasing As levels grain boundary attack was observed. Samples alloyed with Sb show a satisfactory resistance to dezincification and no grain boundary attack. Finally, a combination of As and Sb at low alloying levels provided an excellent dezincification resistance for brass containing typical impurity levels. This paper is part of a Themed Issue on Brass Alloys. © 2016 Swerea KIMAB.

  • 11.
    Elger, Ragna
    et al.
    RISE, Swerea, KIMAB.
    Norling, Rikard
    RISE, Swerea, KIMAB.
    Pettersson, R.
    Jernkontoret, Sweden.
    Corrosion and deposit formation on four steels exposed in the syngas section after a biomass gasifier2016In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 67, no 9, p. 939-951Article in journal (Refereed)
    Abstract [en]

    In this work, three different stainless steels (304L (CrNi-18-8), 253 MA®(CrNiSi-21-11), Kanthal® A-1 (FeCrAl)) and a reference low-alloyed ferritic steel (16Mo3 (Fe0.3Mo)) were exposed in a commercial biomass gasifier for three periods of 9 min, 580 and 1054 h in the temperature range 350–500 °C. Biomass is a fuel with generally higher amounts of chlorine and lower amounts of sulphur compared to coal and there is a current lack of data on materials performance in such environments. A high level of zinc sulphide was observed on the surfaces of all materials after exposure. It is argued that zinc plays a key role in capturing sulphur in this environment, thus preventing iron from sulphidation. Some incorporation of sulphur in the oxide scale was observed for Fe0.3Mo and CrNi-18-8. CrNiSi-21-11 showed some internal oxidation and pitting was observed for the FeCrAl material. All four materials showed acceptable performance with low total metal loss.

  • 12.
    Elger, Ragna
    et al.
    RISE, Swerea, KIMAB.
    Viklund, Peter
    DEKRA Industrial AB, Sweden.
    Pettersson, Rachel
    Jernkontoret, Sweden.
    Laboratory testing to evaluate candidate alloys for superheaters in waste-fired boilers2016In: Materials at High Temperature, ISSN 0960-3409, E-ISSN 1878-6413, Vol. 33, no 6, p. 587-595Article in journal (Refereed)
    Abstract [en]

    Two types of laboratory tests were used to evaluate the behaviour of a wide range of steels in chlorinating–sulphidising conditions: high temperature exposure after applying salt by dipping in an aqueous KCl/ZnCl2 solution and salt-bed test in a ZnCl2/NaCl/KCl/CaSO4 salt mixture. The exposures were performed at 500 °C in a gas comprising N2/HCl/SO2/O2/N2. For the alloy group with 20–30 wt-% chromium and 25–65 wt-% nickel, the extrapolated metal loss was below 0.2 mm/year in the salt dip, up to 6 mm/year in the salt-bed test with 10% Cl and up to 20 mm/year in the 20% Cl salt-bed test. The intermediate alloy group showed poorer performance in the salt-bed; Esshete1250 showed also large spallation in the salt dip test. Results were compared with plant-exposed samples. Further refinement of the salt dip test is suggested for material ranking in the superheater region of a waste or biomass-fired incinerator. © 2016 Swerea Kimab.

  • 13.
    Fahlkrans, Johan
    et al.
    RISE, Swerea, KIMAB.
    Melander, Arne
    RISE, Swerea, KIMAB. KTH Royal Institute of Technology, Sweden.
    Gardstam, Johannes
    RISE, Swerea, KIMAB.
    Haglund, Sven
    RISE, Swerea, KIMAB.
    Straightening of induction hardened shats-inluence on fatigue strength and residual stress2012In: HTM - Haerterei-Technische Mitteilungen, ISSN 0341-101X, Vol. 67, no 3, p. 179-187Article in journal (Refereed)
    Abstract [en]

    Straightening of distorted components ater heat treatment is oten a necessary operation. he straightening operation leads to local plastic deformation, which is afecting the residual stress state, the hardness, and ultimately the fatigue strength of the component. he present study evaluates the inluence of a straightening operation on fatigue strength and on the residual stress state of induction hardened shats of steel EN 42CrMo4. A simpliied FEM model was formulated. he model showed that the residual stress state was asymmetric along the circumference of a straightened shat. Fatigue testing was performed in a three point bending and showed that the fatigue strength was reduced by up to some 20 % by heavy straightening. A fracture mechanics model for fatigue crack growth and arrest was developed. he model could be used to predict the fatigue strength of a straightened shat provided that the residual stress state was known. 

  • 14.
    Fahlström, Karl
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB. RISE, Swerea, KIMAB.
    Andersson, Oscar
    Volvo Cars, Sweden.
    Todal, Urban
    Volvo Cars, Sweden.
    Melander, Arne
    RISE, Swerea, KIMAB.
    Minimization of distortions during laser welding of ultra high strength steel2015In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 27, no S2, article id S29011Article in journal (Refereed)
    Abstract [en]

    Ultra high strength steels are frequently used within the automotive industry for several components. Welding of these components is traditionally done by resistance spot welding, but to get further productivity and increased strength, laser welding has been introduced in the past decades. Fusion welding is known to cause distortions due to built in stresses in the material. The distortions result in geometrical issues during assembly which become the origin of low joint quality due to gaps and misfits. U-beam structures of boron steel simulating B-pillars have been welded with laser along the flanges. Welding parameters and clamping have been varied to create different welding sequences and heat input generating a range of distortion levels. The distortions have been recorded dynamically with an optical measurement system during welding. In addition, final distortions have been measured by a digital Vernier caliper. The combined measurements give the possibility to evaluate development, occurrence, and magnitude of distortions with high accuracy. Furthermore, section cuts have been analyzed to assess joint geometry and metallurgy. The results show that final distortions appear in the range of 0-8 mm. Distortions occur mainly transversely and vertically along the profile. Variations in heat input show clear correlation with the magnitude of distortions and level of joint quality. A higher heat input in general generates a higher level of distortion with the same clamping conditions. Section cuts show that weld width and penetration are significantly affected by welding heat input. The present study identifies parameters which significantly influence the magnitude and distribution of distortions. Also, effective measures to minimize distortions and maintain or improve joint quality have been proposed. Finally, transient finite element (FE) simulations have been presented which show the behavior of the profiles during the welding and unclamping process. 

  • 15.
    Fahlström, Karl
    et al.
    RISE, Swerea, KIMAB. RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Persson, Kjell Arne
    RISE, Swerea, KIMAB.
    Larsson, Johnny
    Volvo Cars, Sweden.
    Vila Ferrer, Elisenda
    Gestamp, Spain.
    Evaluation of laser weldability of 1800 and 1900 MPa boron steels2016In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 28, no 2, article id 022426Article in journal (Refereed)
    Abstract [en]

    Ultrahigh strength steels are frequently used within the automotive industry. The driving force for use of these materials is to exchange thicker gauges to thinner and lighter structures. To get excellent strength and beneficial crash performance, the steel is microalloyed with boron which contributes to the 1500 MPa tensile strength. Increasing the carbon content will give superior tensile strength up to 2000 MPa. Welding of these components is traditionally done by resistance spot welding, but to get further productivity and increased stiffness of the structure, laser welding can be introduced. Welding of boron alloyed high strength steel is in general a stable and controlled process, but if increasing the carbon content quality issues such as cracking could possibly be a problem. In the present study, weldability of two different hardened boron steels with tensile strengths of 1800 and 1900 MPa, respectively, has been evaluated. Laser welding has been done in a lap joint configuration with 3.8-4.7 kW and varying welding speed between 3.5 and 5.5 m/min. As reference, results from more conventional 1500 MPa boron steel have been compared to 1800 and 1900 MPa boron steels to show the influence of the carbon content. Metallographic investigation, hot crack test, cold crack test, shear tensile, and cross-tension strength tests have been done. The results show that a weld quality similar to that for conventional boron steel can be achieved. Cracking and other defects can be avoided. As expected when welding martensitic steels, the failure mode in tensile testing is brittle. No weld defects have been found that influence strength. The sheet interface weld width, which together with stack-up thickness correlates with strength of the joint, could be increased by increasing the heat input and defocusing the laser beam. The effect of increased carbon content on weldability will be discussed more in detail, as well as the risk of cracking.

  • 16.
    Frisk, Karin
    et al.
    RISE, Swerea, KIMAB.
    Borggren, Ulrika
    SSAB, Sweden.
    Precipitation in Microalloyed Steel by Model Alloy Experiments and Thermodynamic Calculations2016In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 47, no 10, p. 4806-4817Article in journal (Refereed)
    Abstract [en]

    Precipitation in microalloyed steel has been studied by applying thermodynamic calculations based on a description of the Gibbs energies of the individual phases over the full multicomponent composition range. To validate and improve the thermodynamic description, new experimental investigations of the phase separation in the cubic carbides/nitrides/carbonitrides in alloys containing Nb, V, Mo, and Cr, have been performed. Model alloys were designed to obtain equilibrium carbides/carbonitrides that are sufficiently large for measurements of compositions, making it possible to study the partitioning of the elements into different precipitates, showing distinctly different composition sets. The reliability of the calculations, when applied to multicomponent alloys, was tested by comparing with published experimental studies of precipitation in microalloyed steel. It is shown that thermodynamic calculations accurately describe the observed precipitation sequences. Further, they can reproduce several important features of precipitation processes in microalloyed steel such as the partitioning of Mo between matrix and precipitates and the variation of precipitate compositions depending on precipitation temperature. 

  • 17.
    Frisk, Karin
    et al.
    RISE, Swerea, KIMAB.
    Magnusson, Hans
    RISE, Swerea, KIMAB.
    Chasoglou, D.
    Höganäs AB, Sweden.
    Bergman, O.
    Höganäs AB, Sweden.
    Studies of oxide reduction during sintering of Cr alloyed PM steel by coupled experimental and diffusion simulations2016In: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Conference paper (Refereed)
    Abstract [en]

    Oxide reduction in Cr alloyed PM steel has been simulated experimentally by measuring the oxygen loss from powders when exposed to a heating cycle, by photo acoustic spectroscopy (PAS) and by thermogravimetric analysis (TGA). Pressed samples were heated in dry hydrogen gas using a defined, slow, heating rate up to 1300oC. The oxides in the powder are reduced by the hydrogen gas. From the PAS curves distinct reduction temperatures are observed, that can be correlated to the type of oxide by comparing with thermodynamic calculations of the oxide stabilities. The experimental results were analyzed by diffusion simulations that involve a description of the diffusion controlled oxide reduction. It is shown how the calculated rate of oxygen diffusion in the samples, compared with the experimental results, has been applied as a tool for increased understanding of the reduction during sintering.

  • 18.
    Frisk, Karin
    et al.
    RISE, Swerea, KIMAB.
    Rännar, L. -E
    Mid Sweden University, Sweden.
    Koptyug, A.
    Mid Sweden University, Sweden.
    Petterson, Niklas
    RISE, Swerea, KIMAB.
    Persson, Daniel
    RISE, Swerea, KIMAB.
    Leicht, A.
    Chalmers University of Technology, Sweden.
    Sundaram, M. V.
    Chalmers University of Technology, Sweden.
    Hryha, E.
    Chalmers University of Technology, Sweden.
    Nyborg, L.
    Chalmers University of Technology, Sweden.
    Ahlfors, M.
    Quintus Technologies, Sweden.
    Characterisation of EBM-built shelled samples of Ti6Al4V compacted by HIP2016In: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Conference paper (Refereed)
    Abstract [en]

    Compaction of additively manufactured Ti6Al4V components by Hot Isostatic Pressing (HIP) is often applied to eliminate porosity, producing fully dense material. In the present work shelled samples produced by Electron Beam Melting with the Arcam process (EBM) were compacted by HIP to produce fully dense samples. Cylindrical samples were studied. The walls of the cylinders were built with EBM, and the powder from the process was left uncompacted inside the cylinders. Samples with different wall thicknesses were produced. The samples were thereafter subjected to a HIP compaction. The critical wall thicknesses needed for compaction were evaluated, and the microstructures characterized. The results show that fully dense samples, with very fine microstructures, are possible.

  • 19.
    Fuertes, Nuria
    et al.
    RISE, Swerea, KIMAB.
    Pettersson, R.
    Jernkontoret, Sweden.
    Review-passive film properties and electrochemical response of different phases in a Cu-alloyed stainless steel after long term heat treatment2016In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 163, no 7, p. C377-C385Article in journal (Refereed)
    Abstract [en]

    In this work the influence of copper (0-4 wt%) on the microstructure, passive film properties and local electrochemical response of 25Cr7Ni-type duplex stainless steel is investigated after long term heat-treatment at 800◦C for 6 months. This heat-treatment was done to promote the formation of different phases which could be studied in terms of passive film properties and electrochemical response. The unique microstructures of the alloys comprise austenite, sigma phase, Cr2N nitrides and, for the 2 wt% and 4 wt% Cu alloys, epsilon-Cu phase. The results show that alloying with Cu increases slightly the amount of isothermal Cr2N nitrides and epsilon-Cu phase, but decreases the sigma phase fraction. The location of pitting corrosion as well as the Electrochemical Potential (EP), or electron work function, measured with Scanning Kelvin Probe Force Microscopy (SKPFM) show that the epsilon-Cu phase has the lowest corrosion resistance. The EP appears to depend more on the composition of the underlying phase than on the thickness of the passive film. Cr-nitrides have the highest EP followed by sigma phase, austenite and epsilon-Cu phase. There is a clear decrease of EP of the austenitic phase when 2 wt% Cu is added in the alloy. 

  • 20.
    Hagberg, Johan
    et al.
    KTH Royal Institute of Technology, Sweden.
    Leijonmarck, Simon
    RISE, Swerea, KIMAB. KTH Royal Institute of Technology, Sweden.
    Lindbergh, Göran
    KTH Royal Institute of Technology, Sweden.
    High precision coulometry of commercial PAN-based carbon fibers as electrodes in structural batteries2016In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 163, no 8, p. A1790-A1797Article in journal (Refereed)
    Abstract [en]

    Carbon fibers have the combined mechanical and electrochemical properties needed to make them particularly well suited for usage as electrodes in a structural lithium-ion battery, amaterial that simultaneously works as a battery and a structural composite. Presented in this paper is an evaluation of commercial polyacrylonitrile-based carbon fibers in terms of capacity and coulombic efficiency, as well as a microstructural and surface evaluation. Some polyacrylonitrile based carbon fibers intercalate lithium ions, resulting in a similar capacity as state-of-the-art graphite based electrodes, presently the most commonly used negative electrode material. Using high precision coulometry, we found a capacity of around 250-350 mAh/g and a very high coulombic efficiency of over 99.9% after ten cycles, which is even higher than a commercial state-of-the art graphitic electrode evaluated as reference. The high coulombic efficiency is attributed to the very low surface area of the carbon fibers, resulting in a small and stable solid-electrolyte interface layer. A highly graphitized ultra high modulus carbon fiber was evaluated as well and, compared to the other fibers, less lithium was inserted (corresponding to approximately 150 mAh/g). We show that the use of carbon fibers as an electrode material in a structural composite battery is indeed viable.

  • 21.
    Hammam, Tag
    et al.
    RISE, Swerea, KIMAB.
    Bjornangen, T.
    Scania CV AB, Sweden.
    Jernberg, G.
    Scania CV AB, Sweden.
    Development of a novel method to detect fretting motion in electrical connectors2016In: ICEC 2016 - 28th International Conference on Electric Contacts, Heriot-Watt University , 2016, p. 87-92Conference paper (Refereed)
    Abstract [en]

    Fretting tests of tin-coated connectors are often performed at exaggerated vibration levels, followed by measurement of the contact resistance. However, the strong vibration might cause stochastic penetration of the vibration induced oxide layer, and the connector might pass the test despite almost the entire contact area being covered by an insulating oxide layer. Therefore, in-situ detection of micro-slip at the contact interface during vibration would be desirable, since micro-motion is a prerequisite for fretting. In a previous study using model contacts, it has been demonstrated that oscillating slip will result in a detectable noise of the contact voltage drop. The electrical noise is probably caused by changes in the pattern of a-spots during the oscillating micro-slip. In this study, it is demonstrated that it is possible to measure the micro-slip induced electrical noise in real connectors. Thus, the vibration threshold level when the micro-slip starts can be determined in situ. Furthermore, this can be performed without influencing the dynamic behavior of the connector or changing the contact interface.

  • 22.
    Heikkilä, Irma
    et al.
    RISE, Swerea, KIMAB.
    Eggertson, Christer
    RISE, Swerea, KIMAB.
    Randelius, Mats
    RISE, Swerea, KIMAB.
    Caddeo-Johansson, S.
    Sandvik Coromant, Sweden.
    Chasoglou, D.
    Höganäs AB, Sweden.
    First experiences on characterization of surface oxide films in powder particles by gd-oes2015In: Proceedings Euro PM 2015: International Power Metallurgy Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2015Conference paper (Refereed)
    Abstract [en]

    The surface characteristics of the powder particles play a key role on the processing of the powders to consolidated products and on the final properties achieved for the material. Characterization of surface oxide films by techniques like XPS and TEM EDS provide reliable information on the surface films, but they are time-consuming methods and the analyzed areas are extremely limited. In this evaluation, the potential of the depth profile analysis by Glow Discharge Optical Emission Spectroscopy (GD-OES) is experimented for Astaloy CrM and 316L powders. The conducted experiments show that the chemical composition and thickness of the surface oxides can be analyzed by GD-OES even for powder materials. Thus, the first results indicate that GD-OES provides a fast method to analyze the surface characteristics of a large number of powder particles during a single measurement.

  • 23.
    Hosseini, Vahid
    et al.
    University West, Sweden; Innovatum AB, Sweden.
    Valiente Bermejo, Ascunsion
    University West, Sweden.
    Gårdstam, Johannes
    RISE, Swerea, KIMAB.
    Hurtig, Kjell
    University West, Sweden.
    Karlsson, Leif
    University West, Sweden.
    Influence of multiple thermal cycles on microstructure of heat-affected zone in TIG-welded super duplex stainless steel2016In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 60, no 2, p. 233-245Article in journal (Refereed)
    Abstract [en]

    The influence of heat input and multiple welding cycles on the microstructure of the heat-affected zone in autogenously TIG-welded 6 mm 2507 type super duplex stainless steel plates was investigated. In order to produce multiple thermal cycles, one to four pass bead-on-plate welds were made with arc energies of 0.47 and 1.08 kJ/mm, corresponding to heat inputs of 0.37 and 0.87 kJ/mm. Several thermocouples were attached to record thermal cycles on the front and back sides of the plates. Finite element modelling was successfully done to map and correlate measured and calculated peak temperatures. Only minor changes were seen in the ferrite content at 1 and 2 mm from the fusion boundary. Nitrides formed in all passes of the low heat input samples in a region next to the fusion boundary, but only after the third and fourth passes of the high heat input samples. Sigma phase precipitated only in a zone heated to a peak temperature in the range of approximately 828 to 1028 °C. Multiple reheating was found to promote precipitation of sigma phase relatively more than slower cooling. A precipitation free zone was observed between the nitride and sigma phase bands. The precipitation behaviour could be understood from equilibrium phase diagrams, evaluation of local thermal cycles and by correlating results from the modelling and measurements of peak temperatures. It is suggested that the peak temperature, the accumulated time in the critical temperature range between approximately 828 and 1028 °C, and the number of thermal cycles are the most relevant criteria when evaluating the risk of sigma phase formation. 

  • 24.
    Hosseini, Vahid
    et al.
    University West, Sweden; Innovatum AB, Sweden.
    Wessman, Sten
    RISE, Swerea, KIMAB. RISE - Research Institutes of Sweden, Materials and Production, KIMAB. University West, Sweden.
    Hurtig, Kjell
    University West, Sweden.
    Karlsson, Leif
    University West, Sweden.
    Nitrogen loss and effects on microstructure in multipass TIG welding of a super duplex stainless steel2016In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 98, p. 88-97Article in journal (Refereed)
    Abstract [en]

    Nitrogen loss is an important phenomenon in welding of super duplex stainless steels. In this study, a super duplex stainless steel was autogenously TIG-welded with one to four bead-on-plate passes with low or high heat inputs using pure argon shielding gas. The goal was to monitor nitrogen content and microstructure for each weld pass. Nitrogen content, measured by wavelength dispersive X-ray spectrometry, was after four passes reduced from 0.28 wt% in the base metal to 0.17 wt% and 0.10 wt% in low and high heat input samples, respectively. Nitrogen loss resulted in a more ferritic structure with larger grains and nitride precipitates. The ferrite grain width markedly increased with increasing number of passes and heat input. Ferrite content increased from 55% in base metal to 75% at low and 79% at high heat inputs after four passes. An increasing amount of nitrides were seen with increasing number of weld passes. An equation was suggested for calculation of the final nitrogen content of the weld metal as functions of initial nitrogen content and arc energy. Acceptable ferrite contents were seen for one or two passes. The recommendation is to use nitrogen in shielding gas and proper filler metals.

  • 25.
    Hutchinson, Bevis
    et al.
    RISE, Swerea, KIMAB.
    Komenda, Jacek
    RISE, Swerea, KIMAB.
    Martin, David
    RISE, Swerea, KIMAB.
    Vanadium microalloyed high Strength martensitic steel sheet for hot-dip coating2015In: 7th International Conference on High Strength Low Alloy Steels, HSLA Steels 2015, International Conference on Microalloying 2015, Microalloying 2015 and International Conference on Offshore Engineering Steels 2015, OES 2015, John Wiley and Sons Inc. , 2015, p. 535-540Conference paper (Refereed)
    Abstract [en]

    Cold rolled steels with various vanadium and nitrogen levels have been treated to simulate the application of galvanizing and galvannealing to hardened martensitic microstructures. Strength levels were raised 100-150MPa by alloying with vanadium, which mitigates the effect of tempering. This opens the way for new ultra-high strength steels with corrosion resistant coatings produced by hot dip galvanising.

  • 26.
    Hutchinson, Bevis
    et al.
    RISE, Swerea, KIMAB.
    Lundin, Peter
    RISE, Swerea, KIMAB.
    Lindh-Ulmgren, Eva
    RISE, Swerea, KIMAB.
    Lévesque, D.
    National Research Council Canada, Canada.
    Anomalous ultrasonic attenuation in ferritic steels at elevated temperatures2016In: Ultrasonics, ISSN 0041-624X, E-ISSN 1874-9968, Vol. 69, p. 268-272Article in journal (Refereed)
    Abstract [en]

    An unexpected peak in attenuation has been observed at ∼800 °C when heating low carbon steels in a laser-ultrasonic instrument. An explanation is given in terms of enhanced crystalline anisotropy with increasing temperature in the bcc ferrite range combined with subsequent transformation to austenite at still higher temperatures. An analysis based on theoretical models of attenuation in the Rayleigh regime is in good agreement with the experimental observations. 

  • 27.
    Jäger, Henrik
    et al.
    RISE, Swerea, KIMAB. University West, Sweden.
    Alagan, N. T.
    University West, Sweden.
    Holmberg, Jonas
    RISE, Swerea, IVF. University West, Sweden.
    Beno, T.
    University West, Sweden.
    Wretland, A.
    EDS Analysis of Flank Wear and Surface Integrity in Machining of Alloy 718 with Forced Coolant Application2016In: Procedia CIRP, Elsevier B.V. , 2016, p. 271-274Conference paper (Refereed)
    Abstract [en]

    There has been extensive research on forced coolant application, usually known as high pressure coolant, in machining heat resistant super alloys. This technology has shown to improve the tool life, chip segmentation, surface integrity and reduce the temperature in the cutting zone. A number of studies have been done on hydraulic parameters of the coolant. This study has been focused on residues on the flank face of the insert and residual stress on the workpiece surface generated by regular and modified cutting inserts. To identify any residual elements, analysis were done by energy dispersive X-ray spectrometer, EDS, on regular as well as modified inserts in combination with forced coolant application on both rake and flank face. The investigations have shown that the temperature gradient in the insert has changed between the regular and modified cutting inserts and that the tool wear and surface roughness is significantly affected by the modified cutting tool. © 2016 The Authors.

  • 28.
    Kamjou, L.
    et al.
    Ovako AB, Sweden.
    Fagerlund, J.
    Ovako AB, Sweden.
    Bylund, N.
    Sandvik Coromant, Sweden.
    Marsh, B.
    Sandvik Coromant, Sweden.
    Björk, Thomas
    RISE, Swerea, KIMAB.
    Performance and machining of advanced engineering steels in power transmission applications - Continued developments2016In: AGMA 2016 - Fall Technical Meeting, AGMA American Gear Manufacturers Association , 2016Conference paper (Refereed)
    Abstract [en]

    Enhancing design, loads, and life of transmission components through innovative steel solutions: It is becoming more and more apparent that material properties can and will play a greater role than before in supporting the challenges most transmission manufacturers are facing today. Making use of materials' intrinsic fatigue properties provides a new design tool to support the market changes taking place, where current and future designs will require cleaner steels that can perform at higher load levels. This paper discusses the potential gain for the transmissions industry by making use of material properties to support more demanding applications. It describes advanced engineering steels and how they can benefit the industry, through discussing material cleanliness versus performance of gear materials, standardized fatigue testing such as contact and bending fatigue as well as machining of clean steel. Full-scale rig testing along with standardized fatigue testing have provided data supporting the gain in performance when moving from conventional steels to clean steels, showing the potential to increase torque and/or downsize through new designs. The value of, for example, having the same design generation running longer is immense, as manufacturing only needs minor adjustments and can be further optimized without large investments. In moving to clean steel, many process steps, including machining, need to be properly evaluated. Therefore, a number of machining trials have been performed comparing clean steel to commonly used conventional steel. In this paper, machining such as turning and gear and spline cutting is discussed, based on a number of recent studies. All studies indicate that by optimizing machining parameters such as tooling inserts, along with ensuring suitable material microstructure, the productivity and efficiency of these processes can be maintained or even improved.

  • 29.
    Komenda, Jacek
    et al.
    RISE, Swerea, KIMAB.
    Martin, David
    RISE, Swerea, KIMAB.
    Lönnqvist, Johan
    RISE, Swerea, KIMAB.
    The effect of boron addition on precipitation and hot ductility of 1.5Mn-0.1Nb-Ti carbon steels in As-cast condition2016In: Materials Science Forum, 2016, Vol. 879, p. 990-995Conference paper (Refereed)
    Abstract [en]

    Twelve experimental steels with a base composition 1.5wt% Mn, 0.01 wt% V and 0.1 wt% Nb and varying C (0.05, 010 and 0.20 wt%), Ti (20 - 260 ppm) and B (0 - 100 ppm) contents have been systematically examined to quantify the effects of composition on precipitation behavio-ur and hot ductility during simulated continuous casting conditions. Nb-rich precipitates were present in the alloys with 0.10 wt-% C and 0.20 wt-% C. Alloys with 0.05, 010 and 0.20wt% C contained 50 - 100 nm size Ti-Nb carbonitrides. Boron was bound in 20 - 100 nm size boronitrides located in prior austenite grain boundaries. A Gleeble 3800 was used to study hot ductility and strain induced precipitation processes in the alloys. Alloys without B and Ti additions exhibited poor hot ductility at 850°C and 950°C, whereas the 0.05 wt-% C and 0.10 wt-% C alloys showed improved hot ductility (reduction in area 40-50%) by the addition of either >50 ppm B or 250 ppm Ti. The 0.2 wt-% C alloys showed no improvement from B or Ti additions. Examination of fracture surfaces of hot ductility specimens showed that boronitrides were located at prior austenite grain boundaries in alloys containing 80 - 100 ppm of B. Compression-relaxation tests showed that alloying with boron caused a noticeable decrease of the start temperature of straininduced precipitation in the alloys.

  • 30.
    Leicht, A.
    et al.
    Chalmers University of Technology, Sweden.
    Sundaram, M. V.
    Chalmers University of Technology, Sweden.
    Yao, Y.
    Chalmers University of Technology, Sweden.
    Hryha, E.
    Chalmers University of Technology, Sweden.
    Nyborg, L.
    Chalmers University of Technology, Sweden.
    Rännar, L. -E
    Mid Sweden University, Sweden.
    Koptioug, A.
    Mid Sweden University, Sweden.
    Frisk, Karin
    RISE, Swerea, KIMAB.
    Ahlfors, M.
    Quintus Technologies AB, Sweden.
    As-HIP microstructure of EBM fabricated shell components2016In: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Conference paper (Refereed)
    Abstract [en]

    Electron Beam Melting (EBM) was used to build Ti-6Al-4V cylindrical shell samples with different wall thickness filled with powder. Built shell samples were HIPed and the difference in microstructure between the EBM-built walls and densified powder inside the shell components was studied as well as the cohesion between these two regions. Components characterization utilizing LOM and SEM+EBSD indicates that columnar grain growth was consistent before and after HIP in the EBM-built part of the components (walls), whereas the densified material in the center of the component had a fine isotropic microstructure, characteristic for HIPed material. The combination of EBM and HIP is shown to be an attractive way of manufacturing complex-shape full density components for high performance applications, involving shortening of built time in the EBM-processing and lead time in capsule fabrication for HIP.

  • 31.
    Lu, Huiran
    et al.
    KTH Royal Institute of Technology, Sweden.
    Behm, Mårten
    KTH Royal Institute of Technology, Sweden.
    Leijonmarck, Simon
    RISE, Swerea, KIMAB. KTH Royal Institute of Technology, Sweden.
    Lindbergh, Göran
    KTH Royal Institute of Technology, Sweden.
    Cornell, Ann
    KTH Royal Institute of Technology, Sweden.
    Flexible Paper Electrodes for Li-Ion Batteries Using Low Amount of TEMPO-Oxidized Cellulose Nanofibrils as Binder2016In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, no 28, p. 18097-18106Article in journal (Refereed)
    Abstract [en]

    Flexible Li-ion batteries attract increasing interest for applications in bendable and wearable electronic devices. TEMPO-oxidized cellulose nanofibrils (TOCNF), a renewable material, is a promising candidate as binder for flexible Li-ion batteries with good mechanical properties. Paper batteries can be produced using a water-based paper making process, avoiding the use of toxic solvents. In this work, finely dispersed TOCNF was used and showed good binding properties at concentrations as low as 4 wt %. The TOCNF was characterized using atomic force microscopy and found to be well dispersed with fibrils of average widths of about 2.7 nm and lengths of approximately 0.1-1 μm. Traces of moisture, trapped in the hygroscopic cellulose, is a concern when the material is used in Li-ion batteries. The low amount of binder reduces possible moisture and also increases the capacity of the electrodes, based on total weight. Effects of moisture on electrochemical battery performance were studied on electrodes dried at 110 °C in a vacuum for varying periods. It was found that increased drying time slightly increased the specific capacities of the LiFePO4 electrodes, whereas the capacities of the graphite electrodes decreased. The Coulombic efficiencies of the electrodes were not much affected by the varying drying times. Drying the electrodes for 1 h was enough to achieve good electrochemical performance. Addition of vinylene carbonate to the electrolyte had a positive effect on cycling for both graphite and LiFePO4. A failure mechanism observed at high TOCNF concentrations is the formation of compact films in the electrodes.

  • 32.
    Magnusson, Hans
    et al.
    RISE, Swerea, KIMAB.
    Chasoglou, D.
    Höganäs AB, SWeden.
    Bergman, O.
    Höganäs AB, SWeden.
    Frisk, Karin
    RISE, Swerea, KIMAB.
    Carbon reactions at sintering of chromium alloyed PM steels2015In: Proceedings Euro PM 2015: International Power Metallurgy Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2015Conference paper (Refereed)
    Abstract [en]

    Carbon has a strong influence on oxide stability. It assists the sintering process by the reduction of oxides on the surface of the powder. Carbon as a small interstitial atom has also a high mobility and can easily diffuse in the material already at relatively low temperature. Due to its high mobility and its influence on oxide reduction it is of interest to predict how carbon is distributed in the sintered body. The carbon distribution in the microstructure will also determine the mechanical properties of the sintered product. Sintering trials have been made for water atomised powder pre-Alloyed with 3wt% chromium and 0.5wt% Mo. These experimental simulations have been made in different N2/H2 atmospheres. The surface reactions during sintering are monitored using photoacoustic spectroscopy, measuring the outgoing gases from the furnace. Computational methods using Thermo-Calc are used to verify the gas reactions taking place in the furnace. By applying kinetic simulations with the Dictra software the carbon diffusion can be modelled for the sintering trials. The computational methods describe the experimentally observed reactions, and contribute to a better understanding of the reduction process.

  • 33.
    Magnusson, Hans
    et al.
    RISE, Swerea, KIMAB.
    Frisk, Karin
    Sundaram, M. V.
    Chalmers University of Technology, Sweden.
    Hryha, E.
    Chalmers University of Technology, Sweden.
    Aslund, C.
    Bofors Bruk, Sweden.
    Bengtsson, B. -O
    Carpenter Powder Products AB, Sweden.
    Ahlfors, Magnus
    Quintus Technologies, Sweden.
    Wiberg, S.
    Linde Gas, Sweden.
    Reaching full density of 100CR6 PM steel by capsule free hot isostatic pressing of high-velocity compacted material2016In: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Conference paper (Refereed)
    Abstract [en]

    Spherical gas atomised 100Cr6 steel powder, processed with the MMS-Scanpac® process to 95% density (agglomeration, followed by conventional pressing, low temperature sintering and re-strike using high velocity adiabatic compaction) has been fully compacted using capsule-free hot isostatic pressing. The material is characterised at different steps of the process and the results are discussed in this paper. Sintering steel powder with high content of carbon requires carbon control at sintering. By continuously measuring the atmosphere at sintering the ingoing gases are adjusted so that carbon control is achieved. Computational work has been made in order to determine how the sintering atmosphere should be adjusted based on the oxygen release and moisture content in the furnace at sintering. KEYWORDS: Capsule free HIP, high velocity compaction, 100Cr6, carbon control.

  • 34.
    Marshakov, A. I.
    et al.
    Russian Academy of Sciences, Russia.
    Rybkina, A. A.
    Russian Academy of Sciences, Russia.
    Maksaeva, L. B.
    Russian Academy of Sciences, Russia.
    Petrunin, M. A.
    Russian Academy of Sciences, Russia.
    Nazarov, Andrej
    RISE, Swerea, KIMAB.
    A study of the initial stages of iron passivation in neutral solutions using the quartz crystal resonator technique2016In: Protection of Metals and Physical Chemistry of Surfaces, ISSN 2070-2051, Vol. 52, no 5, p. 936-946Article in journal (Refereed)
    Abstract [en]

    The initial period of growth of a passive film of iron in borate solutions (pH 7.4 and 6.7) is studied using the quartz crystal resonator technique (EQSN) and pulsed chronoamperometry. Dependences of the surface layer thickness on time are obtained at the metal passivation and prepassivation potentials. Regions corresponding to different stages of passive layer formation are found in anodic current transients, which allowed the ambiguous effect of atomic hydrogen on kinetics of hydrogenated iron dissolution to be explained. It is shown that the iron hydrogenation promoter prevents formation of a primary passive film by accelerating iron dissolution at prepassivation potentials.

  • 35.
    Marty, Florence
    et al.
    Delft University of Technology, Netherlands.
    Gueuné, Herve
    CORRODYS, France.
    Malard, Emelie
    CORRODYS, France.
    Sánchez-Amaya, Jose
    Titania, Spain.
    Sjögren, Lena
    RISE, Swerea, KIMAB.
    Abbas, Ben
    Delft University of Technology, Netherlands.
    Quillet, Laurent
    Université de Rouen, France.
    van Loosdrecht, Mark
    Delft University of Technology, Netherlands.
    Muyzer, Gerard
    Delft University of Technology, Netherlands; University of Amsterdam, Netherlands.
    Identification of key factors in Accelerated Low Water Corrosion through experimental simulation of tidal conditions: Influence of stimulated indigenous microbiota2014In: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 30, no 3, p. 281-297Article in journal (Refereed)
    Abstract [en]

    Biotic and abiotic factors favoring Accelerated Low Water Corrosion (ALWC) on harbor steel structures remain unclear warranting their study under controlled experimental tidal conditions. Initial stimulation of marine microbial consortia by a pulse of organic matter resulted in localized corrosion and the highest corrosion rates (up to 12-times higher than non-stimulated conditions) in the low water zone, persisting after nine months exposure to natural seawater. Correlations between corrosion severity and the abundance and composition of metabolically active sulfate-reducing bacteria (SRB) indicated the importance and persistence of specific bacterial populations in accelerated corrosion. One phylotype related to the electrogenic SRB Desulfopila corrodens appeared as the major causative agent of the accelerated corrosion. The similarity of bacterial populations related to sulfur and iron cycles, mineral and tuberculation with those identified in ALWC support the relevance of experimental simulation of tidal conditions in the management of steel corrosion exposed to harbor environments. 

  • 36.
    Mellin, Pelle
    et al.
    RISE, Swerea, KIMAB.
    Lyckfeldt, Ola
    RISE, Swerea, IVF.
    Harlin, P.
    Sandvik Materials Technology, Sweden.
    Brodin, H.
    Siemens Industrial Turbomachinery AB, Sweden.
    Blom, H.
    Carpenter Powder Products, Sweden.
    Strondl, Annika
    RISE, Swerea, KIMAB.
    Evaluating flowability of additive manufacturing powders, using the gustavsson flow meter2016In: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Conference paper (Refereed)
    Abstract [en]

    The Gustavsson flow meter (including standard ISO-13517) is in this paper used to measure flow rate of fine AM powders. In the current paper, the results are compared to the Hall flow meter and a Freeman FT4 powder rheometer in terms of success of measuring these AM powders. The robustness is clearly superior to the Hall flow meter. Compared to using the rheometer, the Gustavsson flow meter is faster and simpler to use; however, other powder-aspects are evaluated since little correlation was found. All methods of characterizing the flowability could distinguish between (1) two alloys, and (2) if the alloys were new or used (in SLM), and (3) if they were dried or non-dried.

  • 37.
    Mellin, Pelle
    et al.
    RISE, Swerea, KIMAB.
    Ostlund, M.
    Sandvik Materials Technology, Sweden.
    Fredriksson, W.
    Bodycote Hot Isostatic Pressing, Sweden.
    Pellegrini, C.
    Erasteel Kloster, Sweden.
    Blom, H.
    Carpenter Powder Products, Sweden.
    Björnberg, O.
    SIS Swedish Standards Institute, Sweden.
    Strondl, Annika
    RISE, Swerea, KIMAB.
    Detecting argon trapped in reference samples made by hot isostatic pressing2016In: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Conference paper (Refereed)
    Abstract [en]

    We reveal in this paper a procedure to make reference materials containing a known level of Ar. Risk assessment when detecting Ar in a production material is based on the content relative to a specified safety limit (usually 50 ngAr/gsteel). Hence we only need to know if a production material contains more or less than this limit. Now, we can produce material at this limit. To evaluate, we use two types of instruments, on the following contents: 24, 48, 71, 95 and ngAr/gsteel. We found that all instruments could distinguish a higher and a lower level, from the safety limit. These contents are close to the lowest detectable limit for both instruments. The instruments are a G8 Galileo from Bruker Elemental and an ELTRA-Werf (several units) from Takon AB. The mechanisms of Argon segregation are reflected upon as the need for a uniform distribution in reference samples is important. Especially if one would do the instrument calibration solely based on reference samples in the future.

  • 38.
    Mills, Kenneth
    et al.
    London Imperial College ;UK.
    Karagadde, Shyamprasad
    University of Manchester, UK.
    Lee, Peter
    University of Manchester, UK.
    Yuan, Lang
    University of Manchester, UK.
    Shahbazian, Fatameh
    RISE, Swerea, KIMAB.
    Calculation of physical properties for use in models of continuous casting process-Part 1: Mould slags2016In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 56, no 2, p. 264-273Article in journal (Refereed)
    Abstract [en]

    Physical properties of both steels and mould slags are needed as input data for the mathematical modelling of the continuous casting process. Routines for calculating the properties of mould slags and for estimating steel properties have been developed and are described in Parts 1 and 2, respectively. Many mould powders, with differing compositions, are used in casting practice and their properties vary significantly. Reliable models have been developed to calculate these property values as a function of temperature from their chemical composition since this is available on a routine basis. Models have been developed to calculate the following properties: heat capacities, enthalpies, thermal expansion coefficient, density, viscosity, thermal conductivity and surface tension. Solid mould slags can exist as glassy or crystalline phases or as mixtures of the two (i.e. slag films) and the properties for the various phases can vary considerably; methods have been developed to calculate property values for these various states. The software used to calculate the properties is available via the link (i) http://www.mxif.manchester.ac.uk/resources/software (ii) https://sites.google.com/site/shyamkaragadde/software/thermophysical-properties.

  • 39.
    Mills, Kenneth
    et al.
    University of Manchester, UK.
    Karagadde, Shyamprasad
    University of Manchester, UK.
    Lee, Peter
    University of Manchester, UK.
    Yuan, Lang
    University of Manchester, UK.
    Shahbazian, Fatemeh
    RISE, Swerea, KIMAB.
    Calculation of physical properties for use in models of continuous casting process-Part 2: Steels2016In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 56, no 2, p. 274-281Article in journal (Refereed)
    Abstract [en]

    The objective of the present study was to calculate physical property values for steels from their chemical compositions for subsequent use in mathematical models of the fluid flow, heat transfer and shell solidification in the continuous casting mould. Values of the following properties of steels are calculated for temperatures between 298 K and 2 000 K; Heat Capacity (Cp) Density (ρ) Thermal conductivity (k) and diffusivity (a) Electrical resistivity (R) Viscosity (η) Surface (γm) and Interfacial tension (γmsl). In addition temperatures of transitions (Liquidus Tliq, Solidus Tsol) and various solid state transitions were also calculated. Ferritic and austenitic phases of Carbon - and stainless steels are both covered. The associated software is available on the following websites (i) http://www.mxif.manchester.ac.uk/resources/software (ii) https://sites.google.com/site/shyamkaragadde/software/thermophysical-properties.

  • 40.
    Nazarov, Andrej
    et al.
    RISE, Swerea, KIMAB.
    Marshakov, A. I.
    Russian Academy of Sciences, Russia.
    Rybkina, A. A.
    Russian Academy of Sciences, Russia.
    Iron hydrogenation under atmospheric corrosion. Studies using a scanning vibrating microscope2015In: Protection of Metals and Physical Chemistry of Surfaces, ISSN 2070-2051, Vol. 51, no 3, p. 347-359Article in journal (Refereed)
    Abstract [en]

    A scanning vibrating capacitor (SVC, Kelvin probe) is used to study hydrogenation of iron and steel under the conditions of atmospheric corrosion. It is shown that hydrogen that forms in the course of corrosion or under cathodic polarization diffuses through the membrane and interacts with its opposite side, causing a decrease in the surface Volta potential. It is proposed that atomic hydrogen reduces Fe3+ ions in the passive film. It is shown that the SVC technique is informative for registration of local regions of hydrogenated metal at very low hydrogen flow into steel.

  • 41.
    Nazarov, Andrej P.
    et al.
    RISE Research Institutes of Sweden, Materials and Production.
    Diler, Erwan
    RISE Research Institutes of Sweden, Materials and Production.
    Persson, Daniel Pergament
    RISE, Swerea, KIMAB.
    Thierry, Dominique
    RISE Research Institutes of Sweden, Materials and Production.
    Electrochemical and corrosion properties of ZnO/Zn electrode in atmospheric environments2015In: Journal of Electroanalytical Chemistry, ISSN 1572-6657, Vol. 737, p. 129-140Article in journal (Refereed)
    Abstract [en]

    ZnO films of different thicknesses were prepared by thermal oxidation of zinc. The oxide covered surfaces were characterized by Scanning Kelvin Probe (SKP) and Scanning Kelvin Probe-Surface Photovoltage (SKP-SPV) techniques, Infrared Reflection Absorption Spectroscopy (IRRAS), contact angle measurements, and dc voltammetry. The influence of the thickness of ZnO on the absorption of the light, water and oxygen was evaluated. SKP and dc electrochemistry were used to estimate the mechanism of electron exchange between the zinc surface and an aqueous solution containing a red-ox system [Fe(CN)6]2-/[Fe(CN)6]3-. It was shown that ZnO/Zn electrodes with a thick ZnO film nobled the Volta potential that enhanced the electron transfer from the bulk zinc to the molecule of the oxidizer- [Fe(CN)6]3-. Atmospheric corrosion of oxidized zinc surface was investigated after deposition of a single droplet of NaCl aqueous electrolyte. Thicker ZnO films promote the oxygen reduction and the spreading area of the cathodic reaction from the local NaCl contamination. It enlarged the area of metal surface participating in the cathodic reaction and consequently accelerated the atmospheric corrosion. The ability to enhance the oxygen reduction was discussed from the point of view of the band structure and the semiconducting properties of the ZnO layer.

  • 42.
    Prosek, Tomas
    et al.
    RISE, Swerea, KIMAB.
    Hagström, Joacim
    RISE, Swerea, KIMAB.
    Persson, Dan
    RISE, Swerea, KIMAB.
    Fuertes, Nuria
    RISE, Swerea, KIMAB.
    Lindberg, Fredrik
    RISE, Swerea, KIMAB.
    Chocholatý, Ondrej
    University of West Bohemia, Czech Republic.
    Taxen, Claes
    RISE, Swerea, KIMAB.
    Serak, Jan
    University of Chemistry and Technology, Czech Republic.
    Thierry, Dominique
    RISE, Swerea, KIMAB.
    Effect of the microstructure of Zn-Al and Zn-Al-Mg model alloys on corrosion stability2016In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 110, p. 71-81Article in journal (Refereed)
    Abstract [en]

    Zn-5Al and Zn-3Al-2Mg model alloys were cast and heat treated in order to obtain specimens with distinct microstructures and identical chemical compositions. The microstructure was characterised in detail to identify composition, size and distribution of present phases. Mass losses of samples with different microstructures and identical chemical compositions that were subjected to a cyclic corrosion test and a test under non-rinsing conditions differed by a factor of up to two. The mechanism is discussed based on measurements of corrosion stability of individual phases and chemical and phase compositions of corrosion products.

  • 43.
    Prosek, Tomas
    et al.
    RISE, Swerea, KIMAB.
    Nazarov, Andrej
    RISE, Swerea, KIMAB.
    Goodwin, F.
    International Zinc Association, USA.
    Serak, J.
    University of Chemistry and Technology Prague, Czech Republic.
    Thierry, Dominique
    RISE, Swerea, KIMAB.
    Improving corrosion stability of Zn[sbnd]Al[sbnd]Mg by alloying for protection of car bodies2016In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 306, p. 439-447Article in journal (Refereed)
    Abstract [en]

    Aluminium and magnesium are known for their ability to improve corrosion performance of zinc coatings used for steel protection in automotive applications. To investigate the inhibiting properties of other elements, series of model Zn[sbnd]X, Zn[sbnd]Al[sbnd]X, Zn[sbnd]Mg[sbnd]X and Zn[sbnd]Al[sbnd]Mg[sbnd]X alloys containing 0.2–2 wt% of titanium, mischmetal (mixture of cerium and other lanthanides), zirconium, molybdenum, chromium, boron, gallium, indium, copper, nickel, calcium, manganese and silicon were prepared and their corrosion performance in a cyclic accelerated test and at a marine field site and the ability to provide galvanic protection to steel in defects were characterized. On openly exposed surfaces, none of the investigated elements showed stronger inhibiting effect on atmospheric corrosion than Al and Mg. When exposed to marine climate, it was beneficial to combine Al and Mg. The corrosion stability of Zn[sbnd]Al[sbnd]Mg was further improved by addition of a fourth element. Quaternary Zn[sbnd]Al[sbnd]Mg[sbnd]X alloys outperformed binary Zn[sbnd]X and ternary Zn[sbnd]Al[sbnd]X and Zn[sbnd]Mg[sbnd]X alloys. In average, mass loss was 4-fold higher in confined zones simulating hem flanges. Strong inhibition with Mg and detrimental effects of Al on corrosion in confined zones was found. Several quaternary Zn[sbnd]Al[sbnd]Mg[sbnd]X alloys with improved corrosion stability in both open and confined configurations were identified

  • 44.
    Prosek, Tomas
    et al.
    RISE, Swerea, KIMAB.
    Nazarov, Andrej
    RISE, Swerea, KIMAB.
    Le Gac, Anne
    RISE, Swerea, KIMAB.
    Thierry, Dominique
    RISE, Swerea, KIMAB.
    Coil-coated Zn-Mg and Zn-Al-Mg: Effect of climatic parameters on the corrosion at cut edges2015In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 83, p. 26-35Article in journal (Refereed)
    Abstract [en]

    We studied the effect of temperature, wet/dry cycling, pH, and the type and concentration of the corrosion activator on cut edge corrosion of painted Zn-15Mg and Zn-1.5Al-1.5Mg coated steel. In most accelerated tests, paint delamination and red rust formation were reduced compared to hot dip galvanised steel (HDG), and Zn-15Mg outperformed Zn-1.5Al-1.5Mg; however, Zn-1.5Al-1.5Mg showed better results when exposed outdoors. The alloyed materials were particularly resistant when HDG was prone to elevated corrosion, i.e. under permanent wetness, at higher temperatures, with high chloride loadings and in the presence of sulphate. Oxygen reduction on steel cut edges was inhibited by the alloying elements.

  • 45.
    Prosek, Tomas
    et al.
    RISE, Swerea, KIMAB.
    Nazarov, Andrej
    RISE, Swerea, KIMAB.
    Thierry, Dominique
    RISE, Swerea, KIMAB.
    Role of steel and zinc coating thickness in cut edge corrosion of coil coated materials in atmospheric weathering conditions; Part 2: Field data and model2016In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 101, p. 45-50Article in journal (Refereed)
    Abstract [en]

    Paint delamination from cut edges of model coil coated hot dip galvanized materials exposed at a marine test site for 5 years increased with steel thickness and decreased with zinc coating thickness. It was larger in sheltered locations than for openly exposed cut edges whereas red rust protection was more efficient on sheltered edges due to higher electric conductivity of deposits. The rate of paint delamination increased or decreased in time depending on the relative amount of zinc ions available for formation of the protective film on steel controlled by the initial steel substrate and zinc coating thicknesses. 

  • 46.
    Prosek, Tomas
    et al.
    RISE, Swerea, KIMAB.
    Nazarov, Andrej
    RISE, Swerea, KIMAB.
    Xue, HB
    Universidade de Lisboa, Portugal.
    Lamaka, S.
    Universidade de Lisboa, Portugal; Institute of Materials Research, Germany.
    Thierry, Dominique
    RISE, Swerea, KIMAB.
    Role of steel and zinc coating thickness in cut edge corrosion of coil coated materials in atmospheric weathering conditions; Part 1: Laboratory study2016In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 99, p. 356-364Article in journal (Refereed)
    Abstract [en]

    Cathode surface area and its ability to reduce oxygen controlled the rate of zinc dissolution and paint delamination from cut edges of hot dip galvanised steel sheets. Zinc corrosion products deposited on steel in atmospheric exposure conditions inhibited oxygen reduction decreasing galvanic current and zinc dissolution and paint delamination. The opposite effect was observed for iron corrosion products. The initial steel substrate and zinc coating thicknesses affected the availability of zinc ions for formation of the protective film.

  • 47.
    Ratanathavorn, W.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Melander, Arne
    RISE, Swerea, KIMAB. KTH Royal Institute of Technology, Sweden.
    Magnusson, Hans
    RISE, Swerea, KIMAB.
    Intermetallic compounds in friction stirred lap joints between AA5754/galvanised ultra-high strength steel2016In: Science and technology of welding and joining, ISSN 1362-1718, E-ISSN 1743-2936, Vol. 21, no 8, p. 653-659Article in journal (Refereed)
    Abstract [en]

    This paper presents results of joining of AA5754 and DP800 based on the friction stir welding process. Joints were produced by the tool made of H13 tool steel which was allowed to penetrate through the aluminium sheet until reaching the surface of steel sheet without penetrating into it. This approach is an economic and robust way to operate the dissimilar welding process without excessive tool cost. Bonding was achieved by interfacial diffusion reactions between aluminium and iron with a formation of intermetallic compounds. The formation of brittle intermetallic compounds at the interface between the materials was studied. Three intermetallic phases were found at the interface including Al13Fe4, Al5Fe2 and Fe3Zn10. A range of process parameters was identified with a thickness of the intermetallic layers around 2 µm. Shear fracture failure mode was observed under overlap loading. The mechanisms of formation of the joints and factors controlling the strength were discussed. 

  • 48.
    Rendahl, Bo
    et al.
    RISE, Swerea, KIMAB.
    Ström, M.
    Volvo Car, Sweden.
    A capable, simple cyclic replacement to salt spray testing - Part 1 - Exposure results & a draft standard proposal2015In: European Corrosion Congress, EUROCORR 2015, Austrian Society for Metallurgy and Materials (ASMET) , 2015Conference paper (Refereed)
  • 49.
    Rögener, F.
    et al.
    VDEh-Betriebsforschungsinstitut GmbH, Germany.
    Sartor, M.
    VDEh-Betriebsforschungsinstitut GmbH, Germany.
    Reichardt, T.
    VDEh-Betriebsforschungsinstitut GmbH, Germany.
    Bergsjö, Petter
    RISE, Swerea, KIMAB.
    Resistance of plastics in plants of surface technology2015In: Galvanotechnik, ISSN 0016-4232, Vol. 106, no 7, p. 1370-1377Article in journal (Refereed)
    Abstract [en]

    Basically due to their chemical resistance components made of plastics are widely used in pickling, activation/passivation and coating processes. Thus, operational and occupational safety in surface technology depends on the proper selection of these materials. Despite the use of aggressive media-partially at elevated temperatures-little is known about the long-term durability of plastics in these processes. Resistance lists give only inadequate information about the actual behavior under operating conditions, because often the chemical attack of components is intensified by mechanical stress, such as abrasion, shock load, vibrations or cavitation in pumps and pipes. Last but not least, the characteristics of the respective plastics depend also on their processing conditions. The following article should help to raise awareness among metal finishing plants for the dangers emanating from the lack of resistance of synthetic materials.

  • 50.
    Rögener, F.
    et al.
    VDEh-Betriebsforschungsinstitut GmbH, Germany.
    Sartor, M.
    VDEh-Betriebsforschungsinstitut GmbH, Germany.
    Reichardt, T.
    VDEh-Betriebsforschungsinstitut GmbH, Germany.
    Bergsjö, Petter
    RISE, Swerea, KIMAB.
    Römhild, Stefanie
    RISE, Swerea, KIMAB.
    Polymer corrosion in steel pickling lines - Reasons and approaches2013In: Stahl und Eisen (1881), ISSN 0340-4803, Vol. 133, no 1, p. 65-70Article in journal (Refereed)
    Abstract [en]

    The reliability of plant components made of polymers makes a significant contribution in the steel industry to the efficiency of pickling lines, as well as to occupational safety and environmental protection. Owing to their stability against the highly aggressive pickling acids, polymers have been employed successfully for decades as material for tanks, pipes, valves and acid regeneration technology. Most commonly plastics as well as composite materials are used. But, when in contact with pickling acids, even these supposedly acid-resistant materials show phenomena such as degradation, swelling, stress cracking or acid diffusion, which can be also called "Plastic corrosion". Therefore, there is a strong need in the steel industry for increased knowledge on the use of polymers in pickling plants.

12 1 - 50 of 70
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
v. 2.35.10