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  • 1.
    Ahlström, Johan
    RISE, Swerea, Swerea KIMAB.
    Aluminium i betong - Litteraturstudie och experimentella försök2012Report (Refereed)
    Abstract [sv]

    I dagens byggprojekt används en mängd olika material för att bygga konstruktioner. Det förekommer att komponenter av aluminium gjuts in i betong vilket medför en risk att täckskiktet spricker p.g.a. korrosionsprodukternas stora volym. Därför är det viktigt att klargöra vilka korrosionsegenskaper aluminium har ingjuten i betong.

  • 2.
    Ahlström, Johan
    RISE, Swerea, Swerea KIMAB.
    Atmosfäriska korrosionsegenskaper för rostfritt stål med olika ytstruktur2011Report (Refereed)
    Abstract [sv]

    Generellt sett så har rostfria stål en hög korrosionsresistens i atmosfärisk miljö p.g.a. den mycket tunna oxidfilmen på ytan, en film som fungerar som en barriär och försvårar initieringen av en korrosionsprocess på stålets yta. Dock så kan rostfria stål få svåra gropfrätningsangrepp i vissa aggressiva atmosfärer där t.ex. klorider och SO2 finns närvarande. Olika ytstrukturer kan ge ytan olika egenskaper som vätbarhet, ytråhet och ytsammansättning. En yta som har hög vätbarhet har en tjockare fuktfilm på ytan jämfört med en yta som har låg vätbarhet. Det är i fuktfilmen på ytan som korrosionsprocesserna sker, aggressiva partiklar och gaser kan tas upp i fuktfilmen från atmosfären och öka korrosionshastigheten. Ytråheten påverkar både vätbarhet och hur mycket partiklar som fastnar på en yta, därmed påverkar ytråheten korrosionshastigheten. Ytsammansättning anger vilka och hur mycket det finns av ett ämne i den skyddande oxidfilmen, ämnen som kan ha betydelse för hur lätt korrosion uppstår, t.ex. så kan olika sulfider fungera som initieringsyta för korrosionsangrepp. I litteraturen har det dragits olika slutsatser om vilken ytegenskap som har störst betydelse för korrosionens omfattning. Vissa studier säger att ytråheten har störst betydelse medan andra säger att ytsammansättningen har störst betydelse. Särskilt låglegerade ferritiska rostfria stål kan få svår gropfrätning i aggressiva miljöer och då har typen av ytstruktur liten betydelse för hur stora korrosionsangreppen blir. För de mer legerade austenitiska stålen kan typen av ytstruktur ha stor betydelse för storleken på korrosionsangrepp. Höglegerade stål som innehåller molybden har generellt sett små korrosionsangrepp och typen av ytstruktur har liten betydelse för korrosionsangreppens omfattning. Sammantaget tycks det dock vara så att ytråheten ändå har relativt stor inverkan på korrosionsresistensen, dock har relativt få studier genomförts där ytråheten verkligen mätts.

  • 3.
    Ahlström, Johan
    RISE, Swerea, Swerea KIMAB.
    Rostfritt stål i betong med hög fukt och kloridhalt - Provningsmetod för rostfritt stål i betong: Delrapport IV2011Report (Refereed)
    Abstract [sv]

    För betongkonstruktioner som är exponerade i aggressiva miljöer kan korrosionsskador uppstå som kräver kostsamma reparationer. Aggressiva miljöer kan t.ex. vara konstruktioner i kontakt med havsvatten där klorider kan transporteras genom betongskiktet fram till armeringen och där orsakar korrosionsskador. För att förhindra vissa korrosionsskador kan armering av kolstål (som är det vanligaste armeringsmaterialet) bytas ut mot armering i rostfritt stål. Idag finns en mängd olika rostfria stål, med olika korrosionsegenskaper, tillgängliga på marknaden och det är därför viktigt att kunna klassificera korrosionshärdigheten för dessa stål. I en tidigare litteraturstudie ”Elektrokemiska metoder för utvärdering av armeringskorrosion samt kritisk kloridjonkoncentration för rostfritt stål i betong” [1] så undersöktes vad som har rapporterats i litteraturen om provningsmetoder för att undersöka korrosionshärdigheten för rostfritt stål i betong. Det framgick av litteraturstudien att en potentiostatisk metod med polarisering till +200 mV kan vara lämplig. I denna studie har en liknande potentiostatisk metod tillämpats och utvärderats. Provkropparna placerades i ett vattenbad där temperaturen ökade med 5°C per 14 dagar från lägst 20°C till maximalt 40°C. Två austenitiska och tre duplexa stål har undersökts och resultaten visar att stålen EN 1.4301 (304), EN 1.4162 (2101), EN 1.4436 (316) fick korrosionsangrepp vid 4 vikt-% Cl per cementvikt när temperaturen på vattenbadet var mellan 20 och 30°C. Det mer legerade duplexa stålet EN 1.4362 (2304) fick korrosionsangrepp vid 6 vikt-% Cl per cementvikt vid en temperatur på 35°C. Det högst legerade stålet EN 1.4462 (2205) fick inga korrosionsangrepp vid10 vikt-% Cl per cementvikt som var den högsta kloridkoncentrationen.

  • 4.
    Ahlström, Johan
    et al.
    RISE, Swerea, Swerea KIMAB.
    Tidblad, Johan
    RISE, Swerea, Swerea KIMAB.
    Sandberg, Bertil
    RISE, Swerea, Swerea KIMAB.
    Wadsö, L.
    Lund University.
    Galvanic corrosion properties of steel in water saturated concrete2015In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 66, no 1, p. 67-75Article in journal (Refereed)
    Abstract [en]

    Aluminum-based sacrificial anodes were installed to reinforced concrete to stop ongoing corrosion in cooling water tunnels in a Swedish nuclear power plant. The steel rebars were also unintentionally connected to stainless steel water pumps. Therefore, the consumption rate of the sacrificial anodes was higher than predicted. An experimental and a field study were performed to assess if the steel rebar suffer from galvanic corrosion and if the stainless steel pumps are responsible alone for the high consumption rate. It was found from the experimental study that there is an increased risk of galvanic corrosion for steel rebar when the corrosion potential is raised to -200mV (SCE) for samples with 1% CL- by mass of cement and -500mV (SCE) for samples with 2% Cl- by mass of cement. The experimental results were compared with the corrosion potential measured in the cooling water tunnel where sacri ficial anodes were in use and not mounted at all. The cooling water tunnel without sacrificial anodes had generally more anodic corrosion potentials compared to the tunnel with anodes. The tunnel with anodes had also more anodic potentials closer to the stainless steel pumps than further away which means that the rebar is affected by the stainless steel pumps. However, the measured corrosion potentials in the tunnels were not as anodic as the potentials needed for high galvanic current measured in the experimental study. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA.

  • 5.
    Alberts, D.
    et al.
    University of Oviedo.
    Vega, V.
    University of Oviedo.
    Pereiro, R.
    University of Oviedo.
    Bordel, N.
    University of Oviedo.
    Prida, V.M.
    University of Oviedo.
    Bengtson, Arne
    RISE, Swerea, Swerea KIMAB.
    Sanz-Medel, A.
    University of Oviedo.
    In-depth profile analysis of filled alumina and titania nanostructured templates by radiofrequency glow discharge coupled to optical emission spectrometry2010In: Analusis, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 396, no 8, p. 2833-2840Article in journal (Refereed)
    Abstract [en]

    The development of highly ordered and self-assembled magnetic nanostructures such as arrays of Fe or Ni nanowires and their alloys is arousing increasing interest due to the peculiar magnetic properties of such materials at the nanoscale. These nanostructures can be fabricated using nanoporous anodic alumina membranes or self-assembled nanotubular titanium dioxide as templates. The chemical characterization of the nanostructured layers is of great importance to assist the optimization of the filling procedure or to determine their manufacturing quality. Radiofrequency glow discharge (RF-GD) coupled to optical emission spectrometry (OES) is a powerful tool for the direct analysis of either conducting or insulating materials and to carry out depth profile analysis of thin layers by multi-matrix calibration procedures. Thus, the capability of RF-GD-OES is investigated here for the in-depth quantitative analysis of self-aligned titania nanotubes and self-ordered nanoporous alumina filled with arrays of metallic and magnetic nanowires obtained using the template-assisted filling method. The samples analysed in this work consisted of arrays of Ni nanowires with different lengths (from 1.2 up to 5 μm) and multilayer nanowires of alternating layers with different thicknesses (of 1-2 μm) of Ni and Au, or Au and FeNi alloy, deposited inside the alumina and titania membranes. Results, compared with other techniques such as scanning electron microscopy and energy-dispersive X-ray spectroscopy, show that the RF-GD-OES surface analysis technique proves to be adequate and promising for this challenging application. © 2009 Springer-Verlag.

  • 6.
    Alipour, Y.
    et al.
    KTH Royal Institute of Technology.
    Talus, Annika
    RISE, Swerea, Swerea KIMAB.
    Henderson, P.
    KTH Royal Institute of Technology.
    Norling, Rikard
    RISE, Swerea, Swerea KIMAB.
    The effect of co-firing sewage sludge with used wood on the corrosion of an FeCrAl alloy and a nickel-based alloy in the furnace region2015In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188Article in journal (Refereed)
    Abstract [en]

    The effect of digested sewage sludge as a fuel additive to reduce corrosion of furnace walls has been studied. The nickel base alloy Alloy 625 and the iron-chromium-aluminium alloy Kanthal APMT™ were exposed for 14.25. h at the furnace wall in a power boiler burning 100% used (also known as waste or recycled) wood. The test was then repeated with the addition of sewage sludge to the waste wood. The samples were chemically analysed and thermodynamically modelled and the corrosion mechanisms were investigated. The results showed that the co-firing of sewage sludge with recycled wood leads to a reduction in the corrosion. Attack by a potassium-lead combination appeared to be the main corrosion mechanism in Alloy 625 during waste wood combustion, while attack by alkali chloride was found to be dominant in APMT alloy. © 2015 Elsevier B.V.

  • 7.
    Alipour, Y.
    et al.
    KTH Royal Institute of Technology.
    Viklund, Peter
    RISE, Swerea, Swerea KIMAB.
    Henderson, P.
    Vattenfall Research and Development.
    The analysis of furnace wall deposits in a low-NOx waste wood-fired bubbling fluidised bed boiler2012In: VGB PowerTech, ISSN 14353199, 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.

  • 8.
    Allvar, Marie
    RISE, Swerea, Swerea KIMAB.
    MIG/MAG brazing with cold metal transfer2012Report (Refereed)
    Abstract [en]

    In the automotive industry a commonly used material is thin steel sheets coated with a thin layer of zinc for corrosion resistance purposes. Welding of this material, with the high temperatures involved, causes problems with zinc burn-off leading to reduced corrosion resistance. The zinc evaporation also causes arc disturbances leading to spatter formation, pores and difficulties achieving good visual weld quality. The joints are in many cases visible or semi-visible (e.g. visible after opening a door) and “A-grade” quality is demanded, meaning no visible discontinuities are allowed. It also implies a smooth and generally appealing appearance of the joint. An alternative to welding is brazing, and laser brazing meets the requirements but the process is associated with high costs. In the national project “LEX-B”, funded by Vinnova, the possibilities of using arc brazing, in particular one MIG/MAG brazing and two TIG brazing processes, for some automotive applications are investigated. This master thesis is connected to the first part of the project and aims at compiling data for making a selection of the most promising process to investigate and optimise further. LEX-B is conducted in cooperation between Swerea KIMAB AB, Volvo Trucks, Scania CV and University West. The joint of interest is a lap joint between bottom and upper sheets of 1.2 mm and 0.8 mm respectively that represents a joint on the side of a truck cabin. The requirements are visual A-grade quality and tensile shear strength of 300 MPa. In the project the MIG/MAG process Cold Metal Transfer (CMT) was compared to the TIG processes forceTIG and Plasmatron. CMT was experimentally investigated while the results for the other two processes were obtained partly from a previous study and partly from Volvo Trucks where tests were performed simultaneously. A system for measuring data for the process was developed, test specimens were brazed and examined visually and mechanical destructive testing was performed to ensure the tensile shear strength. Parameter studies were done for further process optimisation.

  • 9.
    Andersson, Oscar
    et al.
    KTH Royal Institute of Technology, Sweden.
    Budak, Nesrin
    KTH Royal Institute of Technology, Sweden.
    Melander, Arne
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB. KTH Royal Institute of Technology, Sweden.
    Palmquist, Niclas
    Volvo Car Corporation, Sweden.
    Experimental measurements and numerical simulations of distortions of overlap laser-welded thin sheet steel beam structures2017In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 61, no 5, p. 927-934Article in journal (Refereed)
    Abstract [en]

    Distortions of mild steel structures caused by laser welding were analyzed. One thousand-millimeter U-beam structures were welded as overlap joints with different process parameters and thickness configurations. Final vertical and transverse distortions after cooling were measured along the U-beam. Significant factors, which affect distortions, were identified. Heat input per unit length, weld length, and sheet thickness showed a significant effect on welding distortions. Furthermore, the welding distortions were modeled using FE simulations. A simplified and computationally efficient simulation method was used. It describes the effect of shrinkage of the weld zone during cooling. The simulations show reasonable computation times and good agreement with experiments.

  • 10.
    Andersson, Peter
    RISE, Swerea, Swerea KIMAB.
    Thermal conductivity of thermosetting composite materials2012In: ECCM 2012 - Composites at Venice, Proceedings of the 15th European Conference on Composite Materials, European Conference on Composite Materials, ECCM , 2012Conference paper (Refereed)
    Abstract [en]

    In this work the thermal conductivity, λ, of composite materials is investigated. The experimental results are from the experimental transient hot wire method and the experimental transient plate source method. The measurements are carried out on pure RTM6 epoxy resin and glass fibre and carbon fibre composites. The material is investigated both in its fully cured, pristine shape as well as during curing, consolidation and degradation. The λ-values for pure epoxy, glass fibre composite and material during degradation has been determined.

  • 11.
    Andersson, Peter
    et al.
    RISE, Swerea, Swerea KIMAB.
    Gotte, Anders
    RISE, Swerea, Swerea SWECAST.
    Värmeledningsförmåga hos formmaterial2011Report (Refereed)
    Abstract [sv]

    I den första delen av studien tillverkades och bestämdes värmeledningsförmågan för samtliga provkroppar i olika kvarts/fältspatsander från Baskarpsand. Sanderna skiljer sig åt i medelkornstorlek och kornstorleksfördelning. Två olika självhärdande bindemedel, alfaset och furan, användes. I studiens senare del tillverkades och bestämdes värmeledningsförmågan för provkroppar också i sander baserade på andra mineraler. Dessutom undersöktes ytterligare ett bindemedel, nämligen Coldbox. Resultat för Coldbox redovisas i rapporten, då den inte kommer att ingå i någon publikation. Resultaten från de övriga försök kommer att publiceras i en vetenskaplig tidskrift inom något av områdena gjuteriteknik eller mineralogi. För att tillgodose de tilltänka tidskrifternas publiceringsregler, redovisas inte resultaten för dessa i denna rapport.

  • 12.
    Andersson, Roger
    RISE, Swerea, Swerea KIMAB.
    Self-pierce riveting through 3 sheet metal combinations2011Conference paper (Refereed)
    Abstract [en]

    One way to reduce the CO2 emissions in automotives is to reduce the weight of the Body-In-White. One easy to achieve the weight reduction is to replace steel sheet materials with Al alloys, which is 3 times lighter. One issue is the joining process, especially with combinations between steel grades and AL alloys. Example of combination of mixed material combinations (Al-steel) might be found in the door structure. The reason is because of the AL alloys worthier crash performance so the automotive manufacturer might want to use crash impact beams made by high strength steels in a AL intensive door structure. The joining process between aluminum and steel are problematic due it's not possible to use traditional spot-welding technologies due to the materials total difference in microstructure characteristics as well thermal properties. To overcome this issue then mechanical as well adhesion joining are frequently used. This paper describes a development process and subsequently analysis of a self-pierce rivet (SPR) process between 3 sheet metal combinations. The multi-material combinations in this study were a combination of ultra high strength steels sheets (DP1000) and a Al-alloy (AA 6014). The analysis of the SPR process, in sense of mechanical strengths, has been done by peel-and shear tests. To reduce the amount of future physical tests a virtual FE-model has been developed for the process. This FE model of the process has been subsequently used to analyze the mechanical strength during plastic deformation. By using inverse analysis a correct contact algorithm has been evaluated that would predict the binding force between the rivet and sheet under a deformation process. With this new virtual model it will not only possible to analyze and develop the SPR process but also to achieve the final strength of the joint. © 2011 American Institute of Physics.

  • 13.
    Andersson, Stig Peter
    RISE, Swerea, Swerea KIMAB.
    Thermal conductivity of powders used in continuous casting of steel part 2: Powders2015In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 42, no 6, p. 465-470Article in journal (Refereed)
    Abstract [en]

    Measurements of the thermal conductivity of casting powders are needed to determine the magnitude of the vertical heat flux in the powder bed of a continuous casting mould. The thermal conductivities and thermal diffusivities of four mould powders have been determined using the transient plane source (TPS) and the transient hot wire (THW) methods. The values reported in this investigation are in good agreement with the results of earlier studies which used the THW method. However, the results were significantly different from λeff values obtained in thermal insulation tests. This was attributed to the large contribution to λeff from gaseous conduction which arises from the large temperature gradient across the sample. It was found that the thermal conductivity (λpowd) of the powders had a mean value of 0.125±0.025 W m-1 K-1 for the four powders studied; this value is in good agreement with two other studies; it increased as the temperature increased with a mean temperature coefficient of (dλ/dT59×10-5 W m-1 K-2 for the range 295-1100 K and increased as the bulk density increased (λ295=0.010+1.69×10-4ρbulk W m-1 K-1). © 2015 Institute of Materials, Minerals and Mining.

  • 14.
    Andersson, Stig Peter
    et al.
    RISE, Swerea, Swerea KIMAB.
    Eggertson, Christer
    RISE, Swerea, Swerea KIMAB.
    Thermal conductivity of powders used in continuous casting of steel part 1: Glassy and crystalline slags2015In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 42, no 6, p. 456-464Article in journal (Refereed)
    Abstract [en]

    Measurements of the thermal conductivity (λ) and thermal diffusivity (α) have been carried out on samples of Na2O·SiO2 and four mould slags for temperatures between 295 and 1300 K. These measurements were carried out using the transient plane source (TPS) method (295-373 K) and the transient hot wire (THW) technique (295-1300 K) and the laser pulse (LP) or laser flash method in the case of Na2O·SiO2 Values of l295 were very similar (1.07±0.03 W m-1 K-1) and all samples exhibited a maximum at the critical temperature (Tcrit 51040±10 K) beyond which there was a sharp drop in λTHW with increasing temperature. Measurements were also carried out on semi-crystalline samples with increasing λ and fraction of crystalline phase. These samples also exhibited a sharp drop in the thermal conductivity for temperatures above Tcrit and λTcrit was found to be 1.6±0.05 W m-1 K-1. Thermal conductivity (λLP) values calculated from reported thermal diffusivity (αLP) values were in very good agreement with the measured λTHW values for temperatures between 295 K and Tcrit but λLP values did not decrease with increasing temperature above Tcrit (cf. λTHW). Consequently, it was found that λLP≈7λTHW for mould slags. © 2015 Institute of Materials, Minerals and Mining.

  • 15.
    Angré, Alexander
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    Ahlfors, Magnus
    QuintusTechnologies AB, Sweden.
    Chasoglou, Dimitri
    Höganäs AB, Sweden.
    Larsson, Linn
    AB Sandvik Technologies Material, Sweden.
    Claesson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    Karlsson, Oskar
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    Phase transformation under isostatic pressure in HIP2017In: Powder Metallurgy, ISSN 0032-5899, E-ISSN 1743-2901, Vol. 60, no 3, p. 167-174Article in journal (Refereed)
    Abstract [en]

    The new HIP cooling systems enable very fast cooling rates under isostatic pressure. This does not only enable shorter HIP cycles but also allows complete heat treatment cycles to be performed in one HIP cycle. It has been shown in previous studies that extreme pressures of several thousand bar can push phase transformation towards longer times. The new URQ HIP cooling systems give the opportunity to investigate the impact of pressures up to 2000 bar on phase transformation time dependency. For each of the two materials in this study, a comparison of austenite phase transformation time at 100 and 1700 bar was performed. The study was performed by isothermal heat treatment of specimens for a specific time followed by quenching. To evaluate the influence of pressure on hardenability, the phase fractions were evaluated using grid method on SEM images. The study found significant influence of HIP pressure on hardenability.

  • 16.
    Ankerfors, Caroline
    et al.
    RISE, Swerea, Swerea KIMAB.
    Wågberg, L.
    KTH Royal Institute of Technology.
    Polyelectrolyte complexes for tailoring of wood fibre surfaces2014In: Advances in Polymer Science, ISSN 0065-3195, E-ISSN 1436-5030, Vol. 256, p. s.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. © Springer-Verlag Berlin Heidelberg 2013.

  • 17.
    Arne, B.
    et al.
    RISE, Swerea, Swerea KIMAB.
    Björk, Thomas
    RISE, Swerea, Swerea KIMAB.
    Laser ablation breakdown spectroscopy technique for simultaneous analysis of steel and slags in metallurgical samples2009In: Yejin Fenxi/Metallurgical Analysis, ISSN 10007571, Vol. 29, no 2, p. s.8-13Article in journal (Refereed)
    Abstract [zh]

    The original purpose of this research was to develop a method for fast, simultaneous analysis of both the steel and slag content of heterogeneous metallurgical samples for process control. The method is based on Laser Induced Breakdown Spectroscopy (LIBS). The reason for choosing LIBS is that it can be employed for both conductive and non-conductive materials, and is relatively insensitive to sample shape and surface finish. The heterogeneous samples produced contain large numbers of sub-millimetre slag particles that cannot be completely separated from the surrounding steel in a LIBS analysis. A method has therefore been developed to perform a line scan analysis with approximately 0.5 mm resolution and 10 mm length along the sample. The laser pulse rate is 20 Hz and the scan speed is 1 mm/s. Slag particles appear in the line scan as "polluted areas" of the steel with very high concentrations of e. g. Ca, Al and Si. A mathematical model was developed to evaluate the data in steps, based on a single calibration. Firstly, "clean steel" areas are identified and the steel composition determined. In the second step, the average composition across the entire length of the scan is determined. In the final step, the average slag composition is determined by means of a difference calculation. The method was tested on several samples from the development of the heterogeneous sampler. It was found that the elements C, Si, Mn, P, S and Al can be determined in the steel with an RSD of a few percent. In the slag, the RSD's are higher, around10% for several important elements. It is expected that the method can be further developed for rapid analysis of smaller non-metallic inclusions.

  • 18.
    Atwell, D.L.
    et al.
    Deakin University.
    Barnett, M.R.
    Deakin University.
    Hutchinson, Bevis
    RISE, Swerea, Swerea KIMAB.
    The effect of initial grain size and temperature on the tensile properties of magnesium alloy AZ31 sheet2012In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 549, p. s.1-6Article in journal (Refereed)
    Abstract [en]

    This research aimed to assemble and review data that are relevant to sheet metal formability of the magnesium alloy AZ31. Rolled sheets were processed to give four different grain sizes in the range from 2.9 to 47.1 μm. Similar basal textures were present in all these conditions. Tensile tests were carried out at various temperatures between 25 °C and 240 °C, with some additional tests also made below room temperature in dry ice. Results are presented and discussed relating to strength, ductility, strain rate sensitivity and anisotropy. An optimum grain size of about 7 μm applies for ductility over most of the temperature interval. Uniform elongation decreases steadily with increasing temperature whereas the post-necking and total elongation values increase markedly. Measurements of strength, anisotropy and strain rate sensitivity all indicate a significant role of grain boundary mediated deformation above room temperature. The plastic strain ratio, r, is high at room temperature but decreases considerably, especially for the fine grained conditions, at higher temperatures. Modifications to the active slip modes also occur over the same temperature interval but their effect on plasticity is probably less important than was previously believed. © 2012 Elsevier B.V.

  • 19.
    Barnett, M.R.
    et al.
    Deakin University.
    Ghaderi, A.
    Deakin University.
    Sabirov, I.
    Deakin University.
    Hutchinson, Bevis
    RISE, Swerea, Swerea KIMAB.
    Role of grain boundary sliding in the anisotropy of magnesium alloys2009In: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 61, no 3, p. 277-280Article in journal (Refereed)
    Abstract [en]

    The plastic anisotropy of magnesium alloy sheet drops rapidly with test temperature. It has previously been suggested that this may be due to an increase in the activity of 〈c+a〉 dislocations. The present note points out that the phenomenon may result, instead, from the action of grain boundary sliding. This can explain the strong effect of grain size on anisotropy. Furthermore, it points to a new avenue for alloy development. © 2009 Acta Materialia Inc.

  • 20.
    Bate, Pete
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    Lundin, Peter
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    Lindh-Ulmgren, Eva
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    Hutchinson, Bevis
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    Application of laser-ultrasonics to texture measurements in metal processing2017In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 123, p. 329-336Article in journal (Refereed)
    Abstract [en]

    The paper describes in principle how information about textures can be obtained through the application of laser-ultrasonics (LUS) which can be carried out at elevated temperatures, for example in connection with hot rolling. The benefits from getting a measure of texture in this way are explained together with the proposed methodology which is based on the elastic anisotropic properties of the textured material. Measurements are made using only a single laser pulse and in real-time. Two approaches are presented to modelling the propagation of elastic waves, ray tracing and finite difference modelling. These give consistent results but the latter provides a more complete prediction of the ultrasonic spectrum that can be quantitatively related to measured signals through a cross-correlation procedure. Some experimental results are presented for room temperature measurements on a sheet of interstitial-free steel. Agreement between experimental data and modelling results is good and allows estimation of the 4th order coefficients of the orientation distribution function.

  • 21.
    Bengtson, A.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    LIBS compared with conventional plasma optical emission techniques for the analysis of metals – A review of applications and analytical performance2017In: Spectrochimica Acta Part B - Atomic Spectroscopy, ISSN 0584-8547, E-ISSN 1873-3565, Vol. 134, p. 123-132Article in journal (Refereed)
    Abstract [en]

    This review is focused on a comparison of LIBS with the two most common plasma Optical Emission Spectroscopy (OES) techniques for analysis of metals; spark OES and glow discharge (GD) OES. It is shown that these two techniques have only minor differences in analytical performance. An important part of the paper reviews a direct comparison of the analytical figures of merit for bulk analysis of steels using spark and LIBS sources. The comparison was carried out using one instrument with interchangeable sources, eliminating differences related to the optical system and detectors. It was found that the spark provides slightly better analytical figures of merit. The spark analysis is considerably faster, the simple design of the spark stand has enabled complete automation, both properties of great importance in the metallurgical industry for routine analysis. The analysis of non-metallic inclusions (NMI) with spark and LIBS is presented, in the case of the spark this has become known as Pulse Distribution Analysis (PDA). A very significant difference between the techniques is that the electrical spark typically evaporates ~ 100 times more material than a single laser pulse, resulting in complete evaporation of an NMI present in the evaporated metal. The major advantage of LIBS is that it is localised with very good lateral resolution. The major advantages of spark is that it is much faster (can be done simultaneous with the bulk analysis) and easier to quantify. Compositional Depth Profiling (CDP) is compared for GD-OES and LIBS. It is shown that for applications where GD-OES is well suited, e.g. coated metallic sheet, GD-OES still performs slightly better than LIBS. Similar to the case of NMI analysis, the major advantage of LIBS is the great lateral resolution. This allows elemental surface mapping, as well as CDP of very small areas on μm scale. One further advantage of LIBS is that samples of almost any material, shape and size can be analysed, whereas GD-OES has only limited capabilities for non-flat and small samples. A general conclusion of this review is that LIBS is not likely to replace spark and GD-OES in the foreseeable future, for applications where these techniques are well suited. On the other hand several new applications, particularly in the field of on-line monitoring of industrial processes, are making great inroads for LIBS in the metallurgical and manufacturing industries.

  • 22.
    Bengtson, Arne
    et al.
    RISE, Swerea, Swerea KIMAB.
    Hildebrand, L.
    Technical University of Dortmund.
    Expert systems for prediction of corrosion properities of Zn-based coatings from the chemical analysis2012In: Yejin Fenxi/Metallurgical Analysis, ISSN 10007571, Vol. 32, no 4, p. s.1-5Article in journal (Refereed)
    Abstract [zh]

    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.

  • 23.
    Bengtson, Arne
    et al.
    RISE, Swerea, Swerea KIMAB.
    Randelius, Mats
    RISE, Swerea, Swerea KIMAB.
    Further Development of GD-OES for Surface and Depth Profile Analysis2014Report (Refereed)
    Abstract [sv]

    Glow Discharge Optical Emission Spectroscopy (GD-OES) is a well established technique for Compositional Depth Profiling (CDP), very useful for in-depth elemental analysis of surface layers from 10 nm to 100 µm. It is fast, sensitive and fully quantitative. However, there are a few artefacts requiring further study to improve the accuracy and trueness of the method further, primarily for near-surface applications. Outgassing of volatile compounds present inside the source, mainly water and hydrocarbons, has been established to be a major cause of such artefacts. The most “problematic” element is hydrogen, for the following two reasons: 1) it “cools” the plasma even when present in small quantity and thereby affects the intensities of the emission from almost all other elements; 2) it is very reactive and forms molecular species with other light elements e.g. CH, NH and OH, having emission spectra overlapping several atomic analytical lines; causing “false” or exaggerated surface peaks of the corresponding elements. In this work, methods to reduce the outgassing of volatile compounds have been studied. Attempts to dry and clean the argon gas flowing into the source by means of a chemical filter gave no significant improvement. On the other hand, replacing the “standard” anode made of a copper-beryllium alloy with a pure copper anode was shown to reduce the outgassing significantly. To be more specific, the background signal from atomic hydrogen and associated artefacts are reduced, it is still possible that the amount of molecular hydrogen remains almost constant, without observable effects on the analytical signals. Since molecular emission can originate from the sputtered material of the sample itself, particularly organic coatings, an in-depth study of molecular emission in GD-OES was carried out. It was shown that background signals from such emission can be significantly reduced, provided that the instrument has spectral channels for the emitting molecular species installed. With such channels available, conventional “line interference correction” methods was found to be effective in reducing false elemental signals from molecular emission. Application of the pure copper anode and reduction of molecular background techniques to a heat treated zinc-base coating showed expected improvements in the near-surface part of the depth profile. However, for the major elements of technical importance, the difference compared with the original anode and analytical method was marginal. This is reassuring, since it means that the near-surface artefacts normally do not cause major analytical errors. The element that is most difficult to establish the “trueness” of depth profiles is nitrogen, especially if the surface layer is slightly porous. There are samples where an elevated signal from nitrogen in the top surface cannot be correlated to a vacuum leak, trapped air or molecular emission (CO). Investigations where samples are measured for total nitrogen with conventional techniques are very difficult, since the surface layers showing an elevated content are very thin. Further investigation of such samples with high vacuum techniques, e.g. SIMS, would be of interest. A second part of the project deals with advanced evaluation of depth profile data by means of “expert systems”. An expert system is a computer application that is able to perform tasks which are normally performed by human experts; in this case the aim is to be able to perform e.g. quality control with GD-OES without the need for a qualified human expert to interpret the data. There are several types of “computational statistics” methods that can be employed for such purposes, the most well known is probably multivariate analysis. Other methods can evaluate both numerical and other types of input related to classification based on technical properties, e.g. paint adhesion, scratch resistance etc. The objective of this work is to be able to classify samples according to such technical properties. All such systems need a “training set” of samples with known technical properties. In this work, a relatively large set of steel sheet samples with various zinc-based coatings were classified according to corrosion resistance. Form the GD-OES depth profiles, the coating weights of zinc, aluminium and magnesium were extracted in a data pre-treatment step. Using the rule-based classification algorithm “decision tree” 25 out 29 samples was correctly classified. This “proof of concept” work has shown that it is possible to predict certain technical properties based on a multi-element depth profile. This opens up the possibility for e.g. automated quality inspection of complex coating systems, but also the possibility to use GD-OES depth profiling more effectively as a tool in product development.

  • 24.
    Bengtson, Arne
    et al.
    RISE, Swerea, Swerea KIMAB.
    Sedlakova, Miroslava
    RISE, Swerea, Swerea KIMAB.
    Investigation of computational statistics for evaluation of PDA-OES data – final report of the project Innestyr 32014Report (Refereed)
    Abstract [en]

    The aim of this project was to investigate the potential of applying computational statistics (“data mining”) methods to PDA – OES data to find correlation to defects in the final products as well as changes of parameters during the steelmaking process. The computational methods used were multivariate (MVA) data analysis and the rule-based methods “decision trees” and “neural nets”. The project was carried out in close cooperation with Outokumpu Stainless Avesta and the Royal Institute of Technology (KTH). PDA – OES data from sheet samples with and without surface defects were processed by all three methods, all showing statistically significant and consistent correlation. The formation of surface defects is positively correlated to the number of “medium” to “large” inclusions of the classes AlCaMg and AlCa i.e. mixed oxides of these elements. The second part of the research was an evaluation of variations in inclusion characteristics in different process stages using synthetic slags. A large number of samples were collected from experimental trials with two types of synthetic slags, and the conventional process without slag addition for reference. The samples were taken in the ladle furnace at three stages, and in the tundish in connection with the final test sample before casting. PDA – OES data from these samples were evaluated with MVA and decision tree methods. The results showed that the different process stages can be identified from the PDA-OES data with rather good certainty. No significant difference between the use of synthetic slags and the conventional process was detected. In the course of the evaluation work, it was also found that the computational statistics methods must be used with caution. The reason is that data due to “statistical noise” can be identified as significant, giving misleading results. Further work to reduce this problem will be necessary.

  • 25.
    Bengtson, Arne
    et al.
    RISE, Swerea, Swerea KIMAB.
    Sedlakova, Miroslava
    RISE, Swerea, Swerea KIMAB.
    Optical Emission – Pulse Distribution Analysis (PDA/OES) for applications to Aluminium alloys2012Report (Refereed)
    Abstract [en]

    The technique PDA/OES is briefly reviewed. It is based on detection of the signals from individual sparks in OES analysis, which usually comprises a few thousand sparks in each burn. Sparks hitting inclusions/particles of characteristic elemental composition give rise to “outliers” of higher intensity for “marker” elements characteristic of the particle type. The outliers are extracted by statistical analysis, and processed by the software to identify and quantify the particles. PDA/OES is used mainly in the steel industry, where the main interest is to detect and analyse non-metallic inclusions (NMI). In this work, PDA/OES has been tested for applicability to aluminium alloys. In this case the main interest is metallic particles, but there are also some types of NMI’s of interest. It was found that PDA functions in the same way as in steels, but there are several factors limiting the applicability. Firstly, the smallest detectable particles are about 1 μm diameter, and the particle number density should not exceed about 20000/mm3 for PDA to detect then as individual particles. In aluminium, many particles (precipitates) of interest are much smaller and present in much higher number densities. Secondly, the elements present in the metallic particles also exist as dissolved in the surrounding metal, giving a high and noisy background which limits the possibility to detect signals from the particles as outliers. These constraints has limited the applicability to metallic particles in the several μm range, using Fe as the “marker” element. However, for certain types of NMI it is likely that very small particles down to 1 μm can be detected. The experimental work has shown that the scanning spark technique OPA can provide additional useful analytical information. Macroscopic segregation at the mm – several cm ranges can rapidly be investigated in two dimensions. In combination with PDA, macroscopic “clusters” of particles can be mapped.The spark optical emission techniques PDA/OES and Original Position Analysis (OPA) have been investigated for application to aluminium alloys. PDA/OES has been optimised for detection and quantification of metallic particles in the several µm range with. The OPA technique has been evaluated for rapid determination of macroscopic segregation.

  • 26.
    Bengtson, Arne
    et al.
    RISE, Swerea, Swerea KIMAB.
    Sedlakova, Miroslava
    RISE, Swerea, Swerea KIMAB.
    Didriksson, R.
    SSAB EMEA.
    Rapid inclusion characterisation by pulse distribution analysis optical emission spectroscopy-recent development2013In: Yejin Fenxi/Metallurgical Analysis, ISSN 10007571, Vol. 33, no 1, p. s.7-12Article in journal (Refereed)
    Abstract [zh]

    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.

  • 27.
    Bengtson, Arne
    et al.
    RISE, Swerea, Swerea KIMAB.
    Vainik, Rein
    RISE, Swerea, Swerea KIMAB.
    Comparison of GD-MS and LA-ICPMS direct solid sampling techniques for trace elemental analysis of steels2013Report (Refereed)
    Abstract [sv]

    The objective of this project is to evaluate commercially available techniques for trace elemental analysis of steels using direct solid sampling. Such methods have the potential to increase sample throughput and thereby reduce analysis costs. Glow Discharge Mass Spectrometry (GD-MS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) were evaluated. Five certified reference materials (CRM) were selected for the experimental work; a high purity iron, a carbon steel and three high alloy steels. For both types of instruments, the sample set was first used for calibration, then run as unknowns several times in order to get sufficient statistics for the evaluation. The GD-MS measurements were carried out at the Thermo Fisher Scientific applications laboratory in Bremen. The LA-ICPMS work was carried out at KIMAB. Prior to the measurements reported here, the effects of varying instrumental parameters of LA-ICPMS were investigated in order to develop a suitable method for steels. The results show that both techniques are powerful methods for simultaneous determination of a large number of trace elements in steels. A limitation is that none of the techniques is capable of analysing C, N and O, due to gas leaks and contamination from materials in the sources. The overall performance in terms of precision and detection limits is better for GD-MS, but for several applications LA-ICPMS provides sufficient performance. Both techniques have instrumentally limited detection limits at the ppb level or below, but the results on the test samples mostly give considerably higher standard deviations, also at very low concentration levels. Therefore, the analytical accuracy for traces is more limited than one would expect based on the instrumental capabilities; typically in the low ppm range or slightly below. The most likely reason for this is the combination of material inhomogeneity and small sampling volumes. This affects LA-ICPMS the most, due to considerably lower sampling volume than GD-MS.

  • 28.
    Bengtson, Arne
    et al.
    RISE, Swerea, Swerea KIMAB.
    Vainik, Rein
    RISE, Swerea, Swerea KIMAB.
    Synthetic standards for determination of trace elements in steels by solid sampling techniques2015Report (Refereed)
    Abstract [en]

    Accurate determination of trace elements in steels is of importance for several reasons. Some trace elements are added on purpose to influence the metallurgy of the steel, and it is important to control the content to the correct level. Other trace elements are deleterious to certain steel properties and must be controlled to be below maximum levels in order to ensure the quality. In more recent years, national and international legislation demand from steel producers to declare the content of certain environmentally hazardous elements, mainly heavy metals such as Hg, Pb and Cd. Multi-element techniques based on direct solid sampling is of great interest due to the short analysis times, but there is a lack of suitable reference materials (RM) for calibration. Bundesanstalt für Materialprüfung (BAM) in Berlin has therefore developed a technique to produce synthetic solid RM’s for trace analysis. The technique is based on mixing metal powder with small amounts of trace elements in liquid solution, drying and compacting the powder into solid briquettes. A few stainless steel RM’s produced at BAM were used at KIMAB to determine Ce, La, Nd and Pr in a stainless steel CRM, using an LA-ICPMS instrument. The results showed very good agreement with certified values. Six RM’s of the same type were subsequently prepared at KIMAB, doped with Pb, Cd and Hg at levels from 0,1 μg/g to 30 μg/g. The RM’s were first analysed by wet chemical ICP-MS at ALS in Luleå. The results showed nearly 100% recoveries of Pb and Cd, while most of the Hg had been lost in the sample preparation. The samples were then used to calibrate the LA-ICPMS instrument for Pb and Cd. It was found that the signals from the top surface of the samples were very high, indicating a considerable degree of “elemental fractionation. A “preburn” in the form of an ablation linear scan across the sample surface was therefore needed prior to the analysis scan. Very good linear calibration curves were obtained for Pb and Cd, but with apparently higher background levels than in solid steel. Three stainless steels with previously determined contents of Pb just below 2 μg/g were analysed together with the synthetic RM’s, giving intensities significantly below the calibration curve. Assuming a zero background level give calculated mass fractions in near agreement with certified values, but this is not a satisfactory calibration method. It is therefore concluded that in present form, synthetic RM’s are only reliable as calibration samples for LA-ICPMS measurements at trace levels larger than 10 μg/g. Further work is necessary in order to reduce this limit

  • 29.
    Bratberg, Johan
    et al.
    Thermo-Calc Software AB.
    Ågren, J.
    Royal Institute of Technology.
    Frisk, Karin
    RISE, Swerea, Swerea KIMAB.
    Diffusion simulations of MC and M7C3 carbide coarsening in bcc and fee matrix utilising new thermodynamic and kinetic description2008In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 24, no 6, p. 695-704Article in journal (Refereed)
    Abstract [en]

    A new thermodynamic database has been combined with an existing kinetic database to perform coarsening simulations in ternary systems including MC and M7C3 carbides in an fee matrix. The kinetic database was revised taking into consideration the new experimental information on the Fe-Cr-V-C system obtained in the present work, and available experiments on the ternary Fe-Cr-C and Fe-V-C systems. After revision the agreement between experimental results and simulations was satisfactory. It was found that the interfacial energy of M7C3 was twice as large as that of the MC carbide. The calculations for commercial steels with 6 alloy elements gave results in satisfactory agreement with new experimental measurements. The present coarsening simulations use the calculated equilibrium state and the observed particle sizes as the state for the start of the simulations. All the simulations were performed with the DICTRA software. © 2008 Institute of Materials, Minerals and Mining.

  • 30.
    Caddéo, Sophie
    et al.
    RISE, Swerea, Swerea KIMAB.
    Strondl, Annika
    RISE, Swerea, Swerea KIMAB.
    Söderberg, Hans
    RISE, Swerea, Swerea KIMAB.
    Study on oxygen reduction effects due to sintering parameters for sintered steel materials2012Report (Refereed)
    Abstract [sv]

    Three sinter steel materials, AD15, AD4 and Astaloy CrM, have been under evaluation in this study. The study has been focusing on three types of trials in order to see how the sintering parameters influence the reduction of oxides. The first series of trails were focused on how the green body density affects the reduction rate. The second and third series of trail were more focused on the sintering parameters, i.e. sintering time and sintering atmospheres, respectively. For sinter steel pellets a clear effect of the green body density can be seen on PAS and oxygen analyses. A higher green body density decreases the oxygen reduction reactions during sintering and results in higher oxygen content in the final pellet. How the hydrogen content in the sintering atmosphere affects the reduction efficiency is still not clear as the results from the PAS and the chemical and microstructure analysis had different outcome. Further studies are required. The total reduction time has effect on the reduction result i.e. a longer reduction time will reduce more than a faster reduction time.

  • 31.
    Casals, Nuria Fuertes
    et al.
    RISE, Swerea, Swerea KIMAB.
    Viklund, Peter
    RISE, Swerea, Swerea KIMAB.
    Influence of annealing oxide structure and composition on pickling of the duplex stainless steel 1.44622011In: 7th European Stainless Steel Conference: Science and Market, Proceedings, Associazione Italiana di Metallurgia , 2011Conference paper (Refereed)
    Abstract [en]

    In this work, correlation between the oxide formation and pickling behaviour of a conventional duplex material - 1.4462 is reported. The materials investigated are the duplex grade 1.4462 and two single phase alloys with compositions corresponding to the respective phases of the duplex material. Annealing was conducted at 1070 °C for 8 minutes. Topography and composition of the oxide layer were analysed with GDOES, FIB, XRD, SEM-EDS and CLSM. The ferritic steel formed a thick chromium-enriched oxide with a silica-rich sublayer. On the austenitic steel, ironenriched nodules were observed in the centre of the grains, together with oxide ridges on the top of the grain boundaries. The oxide on the duplex grade differed depending on the phase; nodule formation was observed on the austenitic grains while a more homogenous oxide formed on the ferritic grains. Pickling was performed in a mixed nitric/hydrofluoric acid bath. The fastest removal was observed for the austenitic sample, followed by the duplex and the ferritic samples. The oxide on the austenitic sample spalled from the surface while the oxide on the ferritic grade was removed by dissolution rather than by spallation. A mixed behaviour was observed on the duplex grade where some zones pickled faster than others.

  • 32.
    Chasoglou, D.
    et al.
    RISE, Swerea, Swerea KIMAB.
    Senaneuch, J.
    RISE, Swerea, Swerea KIMAB.
    Berg, S.
    Höganäs AB.
    Surredi, K.B.
    Chalmers University of Technology.
    Troell, Eva
    RISE, Swerea, Swerea IVF.
    High performance structural PM steel components by means of induction sintering2014In: Advances in Powder Metallurgy and Particulate Materials - 2014, Proceedings of the 2014 World Congress on Powder Metallurgy and Particulate Materials, PM 2014, Metal Powder Industries Federation , 2014, p. 56-515Conference paper (Refereed)
    Abstract [en]

    In an effort to find alternative routes for the production of sintered parts, induction sintering has been considered a promising candidate because it incorporates short production times. This study is a novel approach which explores the possibility of producing PM steel parts by means of induction sintering. In this work, green compacts from Distaloy-DH powder have been induction sintered at different temperatures and by varying the sintering time and atmosphere. The role and behavior of lubricant and graphite additions during the process were also examined. Conventional sintering was also performed for comparison. Results from the microstructural investigation show complete dissolution of both the diffusion-bonded Cu and the admixed graphite during sintering. Induction sintered samples showed improved mechanical properties which were confirmed by fractographic investigation. The study shows that by careful adjustment of the different sintering parameters it is possible to acquire high performance PM parts through the induction sintering route.

  • 33.
    Chasoglou, Dimitris
    RISE, Swerea, Swerea KIMAB.
    Effect of reducing agents on the sintering of chromium alloyed PM steels2013In: International Powder Metallurgy Congress and Exhibition, Euro PM 2013, European Powder Metallurgy Association (EPMA) , 2013Conference paper (Refereed)
    Abstract [en]

    The control of the surface chemistry during sintering is the key factor for the successful and efficient production of PM parts, especially for powders containing elements with high affinity to oxygen such as chromium. The effect of different reducing agents was investigated by performing sintering trials on water atomized steel powder pre-alloyed with 3 wt.% Cr with and without the addition of graphite as well as using atmospheres with varying hydrogen content. The use of thermal analysis and photoacoustic spectroscopy in combination with results from fractographic investigation showed that oxide reduction is enhanced with the presence of hydrogen even if the main reduction mechanism is the carbothermal reactions. Oxides rich in Cr, Mn and Si were formed during sintering for all applied conditions. The findings are summarized in a simple model describing the enclosure of oxides during the sinter-neck development and the changes in surface chemistry during the process.

  • 34.
    Chasoglou, Dimitris
    RISE, Swerea, Swerea KIMAB.
    Optimisation of sintering atmospheres for controlled sintering of PM steels2013In: International Powder Metallurgy Congress and Exhibition, Euro PM 2013, European Powder Metallurgy Association (EPMA) , 2013Conference paper (Refereed)
    Abstract [en]

    The use of elements with high oxygen affinity such as Cr or Mn in PM steels has been met with skepticism although such grades are attractive options for structural applications. They require strict control of the used atmosphere during the sintering process. Various techniques such as photoacoustic spectroscopy (PAS) and continuous CO/CO2/H2O measurements have been implemented for atmosphere monitoring during sintering trials of Cr-alloyed steel powder. The used atmospheres were nitrogen-hydrogen blends (0, 3, 10 and 100% H2) as well as vacuum. The progress of the oxidation/reduction processes was also followed with thermogravimetric studies. The pressed and sintered samples were examined using optical and electron microscopy in combination with EDX in order to evaluate the formed reaction products. The presence of hydrogen, even in small amounts, is positive for the oxide reduction. Results show that careful adjustment of the used atmosphere leads to efficient production of steel components based on Cr-prealloyed powders.

  • 35.
    Chasoglou, Dimitris
    RISE, Swerea, Swerea KIMAB.
    Surface and bulk characterization of metallic powders [Untersuchung der Oberflächen- und Bulk-Eigenschaften von Metallpulvern]2013In: Praktische metallographie, ISSN 0032-678X, E-ISSN 2195-8599, Vol. 50, no 12, p. 799-809Article in journal (Refereed)
    Abstract [en]

    Metallic components manufactured via the Powder Metallurgy route require more attention in terms of adjusting the process parameters in order to control the chemistry during production. Therefore the first step towards a robust production through the Powder Metallurgy route is the characterization of the chemical features of the metal powder both on the surface and in the bulk This review is an assortment of examples of characterization studies used for investigating different features observed in metallic powders. ©Carl Hanser Verlag, München.

  • 36.
    Chasoglou, Dimitris
    et al.
    RISE, Swerea, Swerea KIMAB.
    Lindvall, Greta
    RISE, Swerea, Swerea KIMAB.
    Magnusson, Hans
    RISE, Swerea, Swerea KIMAB.
    Strondl, Annika
    RISE, Swerea, Swerea KIMAB.
    Frisk, Karin
    RISE, Swerea, Swerea KIMAB.
    Computational predictions with coupled experimental investigations of the effect of alloying elements on microstructure in PM-HIP alloys2013In: International Powder Metallurgy Congress and Exhibition, Euro PM 2013, European Powder Metallurgy Association (EPMA) , 2013Conference paper (Refereed)
    Abstract [en]

    Steel produced by the PM-HIP route has a more homogenous microstructure compared with that obtained in conventionally produced material. This is an important advantage in many applications, and is therefore of interest to predict. The homogeneity of the microstructure is possible due to the rapid solidification of the powder grains in the atomization and the small size of the powder grains. Computational predictions of the variations of composition in powder grains, compacted material and conventionally produced material are compared with microstructure investigations. The microstructure is investigated in SEM with coupled composition analysis by EDS/WDS. The computational predictions are based on a description of the equilibria in the steel, and of the kinetics of segregation on solidification. The effect of alloying elements is discussed, and the effect in a stainless steel and in a tool steel is calculated.

  • 37.
    Chen, Jiaxin
    et al.
    Studsvik Nuclear AB, Sweden.
    Lindberg, Fredrik
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    Wells, Daniel
    Electric Power Research Institute, USA.
    Bengtsson, Bernt
    Ringhals AB, Sweden.
    EELS and electron diffraction studies on possible bonaccordite crystals in pressurized water reactor fuel CRUD and in oxide films of alloy 600 material2017In: Nuclear engineering and technology : an international journal of the Korean Nuclear Society, ISSN 1738-5733, E-ISSN 2234-358X, Vol. 49, no 4, p. 668-674Article in journal (Refereed)
    Abstract [en]

    Experimental verification of boron species in fuel CRUD (Chalk River Unidentified Deposit) would provide essential and important information about the root cause of CRUD-induced power shifts (CIPS). To date, only bonaccordite and elemental boron were reported to exist in fuel CRUD in CIPS-troubled pressurized water reactor (PWR) cores and lithium tetraborate to exist in simulated PWR fuel CRUD from some autoclave tests. We have reevaluated previous analysis of similar threadlike crystals along with examining some similar threadlike crystals from CRUD samples collected from a PWR cycle that had no indications of CIPS. These threadlike crystals have a typical [Ni]/[Fe] atomic ratio of ∼2 and similar crystal morphology as the one (bonaccordite) reported previously. In addition to electron diffraction study, we have applied electron energy loss spectroscopy to determine boron content in such a crystal and found a good agreement with that of bonaccordite. Surprisingly, such crystals seem to appear also on corroded surfaces of Alloy 600 that was exposed to simulated PWR primary water with a dissolved hydrogen level of 5 mL H2/kg H2O, but absent when exposed under 75 mL H2/kg H2O condition. It remains to be verified as to what extent and in which chemical environment this phase would be formed in PWR primary systems.

  • 38.
    Christodoulakis, John
    et al.
    National and Kapodistrian University of Athens, Greece.
    Tzanis, Chris G.
    National and Kapodistrian University of Athens, Greece.
    Varotsos, Costas A.
    National and Kapodistrian University of Athens, Greece.
    Ferm, Martin
    IVL Swedish Environmental Research Institute, Sweden.
    Tidblad, Johan
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB.
    Impacts of air pollution and climate on materials in Athens, Greece2017In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 17, no 1, p. 439-448Article in journal (Refereed)
    Abstract [en]

    For more than 10 years now the National and Kapodistrian University of Athens, Greece, has contributed to the UNECE (United Nations Economic Commission for Europe) ICP Materials (International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments) programme for monitoring the corrosion/soiling levels of different kinds of materials due to environmental air-quality parameters. In this paper we present the results obtained from the analysis of observational data that were collected in Athens during the period 2003-2012. According to these results, the corrosion/soiling of the particular exposed materials tends to decrease over the years, except for the case of copper. Based on this long experimental database that is applicable to the multi-pollutant situation in the Athens basin, we present dose-response functions (DRFs) considering that "dose" stands for the air pollutant concentration, "response" for the material mass loss (normally per annum) and "function", the relationship derived by the best statistical fit to the data.

  • 39.
    Cieślik, M.
    et al.
    Jagiellonian University.
    Engvall, Klas
    RISE, Swerea, Swerea KIMAB.
    Pan, J.
    Royal Institute of Technology.
    Kotarba, A.
    Jagiellonian University.
    Silane-parylene coating for improving corrosion resistance of stainless steel 316L implant material2011In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 53, no 1, p. 296-301Article in journal (Refereed)
    Abstract [en]

    The corrosion resistance of a two-layer polymer (silane+parylene) coating, on implant stainless steel was investigated by microscopic observations and electrochemical measurements. Long term exposure tests in Hanks solution revealed that the coating of 2μm can be successfully used for corrosion protection. However, the addition of H2O2, simulating the inflammatory response of human body environment causes a dramatic destruction of the protective coating. Analysis of the experimental data in terms of circuit models enables proposing a deterioration mechanism. OH radicals formed at the metal surface attack the polymer, thus the deterioration starts from the metal/polymer interface and progress towards the outward surface. © 2010 Elsevier Ltd.

  • 40.
    Cieślik, M.
    et al.
    Jagiellonian University.
    Kot, M.
    AGH University of Science and Technology.
    Reczyński, W.
    AGH University of Science and Technology.
    Engvall, Klas
    RISE, Swerea, Swerea KIMAB.
    Rakowski, W.
    AGH University of Science and Technology.
    Kotarba, A.
    Jagiellonian University.
    Parylene coatings on stainless steel 316L surface for medical applications: Mechanical and protective properties2012In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 32, no 1, p. 31-35Article in journal (Refereed)
    Abstract [en]

    The mechanical and protective properties of parylene N and C coatings (2-20 μm) on stainless steel 316L implant materials were investigated. The coatings were characterized by scanning electron and confocal microscopes, microindentation and scratch tests, whereas their protective properties were evaluated in terms of quenching metal ion release from stainless steel to simulated body fluid (Hanks solution). The obtained results revealed that for parylene C coatings, the critical load for initial cracks is 3-5 times higher and the total metal ions release is reduced 3 times more efficiently compared to parylene N. It was thus concluded that parylene C exhibits superior mechanical and protective properties for application as a micrometer coating material for stainless steel implants. © 2011 Elsevier B.V. All rights reserved.

  • 41.
    Cieślik, M.
    et al.
    Jagiellonian University.
    Reczyński, W.
    AGH University of Science and Technology.
    Janus, A.M.
    Institute of Metallurgy and Materials Engineering, Poland.
    Engvall, Klas
    RISE, Swerea, Swerea KIMAB.
    Socha, R.P.
    Polish Academy of Sciences.
    Kotarba, A.
    Jagiellonian University.
    Metal release and formation of surface precipitate at stainless steel grade 316 and Hanks solution interface: Inflammatory response and surface finishing effects2009In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 51, no 5, p. 1157-1162Article in journal (Refereed)
    Abstract [en]

    The influence of surface finishing (polishing and passivation) on the release of Cr, Fe, Ni from the stainless steel 316 implant materials to Hanks solution with or without H2O2 (simulating a body inflammatory response) was investigated. The surfaces were characterized by means of SEM EDXS, XPS and Kelvin Probe measurements before and after exposure to the synthetic body fluids. The total metal ions release rates are more than 10 times higher in the presence of H2O2, independently of the surface finishing. In the absence of H2O2, formation of a surface layer consisting mainly of Ca3(PO4)2 was observed, most likely it was responsible for the observed decrease of the release rates. © 2009 Elsevier Ltd. All rights reserved.

  • 42.
    Comanescu, Iulian
    RISE, Swerea, Swerea KIMAB.
    Influence of MIC on corrosion of oil field water injection pipelines2013In: Annual Conference of the Australasian Corrosion Association 2013: Corrosion and Prevention 2013, Australasian Corrosion Association , 2013, p. 143-152Conference paper (Refereed)
    Abstract [en]

    Water injection or water flooding is widely used as a secondary recovery method to increase the production of oil usually from mature oil wells. It requires the injection of water into the reservoir, typically using carbon steel pipelines. Their corrosion is a major issue for the oil and gas industry, involving high costs of periodic chemical treatment, including biocides, oxygen scavengers, corrosion and scale inhibitors, and pipeline pigging. There is also the high potential cost of premature failure of the pipelines relative to life-time predictions, and the associated potential for unpredicted costs and major environmental implications should the pipeline fail. The present paper presents a review of a pilot study supported by the oil industry and the European Community that aimed to improve understanding of the corrosion behaviour of these pipelines. It draws on data and observations for the long-term corrosion, water quality, intelligent pigging records and microbiological testing to gain a better understanding why some pipelines suffer mild corrosion yet others, apparently similar, are prone to highly aggressive channelling corrosion. Herein the documented experience of several pipelines is reviewed. Observation data taken into consideration include pigging operation information, composition of corrosion products and their amount, corrosion rates and pipe geometry, identified biological consortia, water chemistry and process parameters. Also, the distribution of corrosion along the pipeline as well as the localization of corrosion attack is noted. Preliminary correlations between and conclusions about observed corrosion, operational conditions and service history are made. A Joint Industry research project currently is being arranged by the offshore oil industry to extend this work. Copyright © 2013 by the Australasian Corrosion Association.

  • 43.
    Comanescu, Iulian
    et al.
    RISE, Swerea, Swerea KIMAB.
    Johansson, Eva
    RISE, Swerea, Swerea KIMAB.
    Data base and corrosion models for MIC in oil & gas2011In: European Corrosion Congress 2011, EUROCORR 2011, 2011, Vol. 3, p. 2574-Conference paper (Refereed)
    Abstract [en]

    Systems for handling stabilised oil like equipment for top side oil export systems, oil transport and processing plants are subject to high level of bio-corrosion. Bio-corrosion results in extensive and costly damages for the equipment and additional losses due to the shutting down of the transport and production units for several weeks. The objective of this project is to build a database of bio-corrosion case histories on carbon steel in systems containing produced water, to design a statistical model correlating physical and chemical parameters and to create a basis for modelling the prediction of MIC in produced water, as e.g. extracted from the hydrocarbon stream. The intention is to develop the data base to an expertise tool for MIC that can be used for anticipating and preventing bio-corrosion. The work is following the methodology "From the field, through the lab, to the field". The work starts with an extensive literature study for collection of published MIC failures in relevant environments. Additionally, close interactions will be held with field operators within Statoil, M-I SWACO and other oil & gas related companies for collection of MIC failures from the fields. In order to have statistical data existing field and literature data will be complemented with field and laboratory studies both within and outside the Marie Curie BIOCOR ITN. A schematic view of the procedure for the work is given below.

  • 44.
    Comanescu, Iulian
    et al.
    RISE, Swerea, Swerea KIMAB.
    Melchers, R.E.
    The University of Newcastle.
    Taxén, Claes
    RISE, Swerea, Swerea KIMAB.
    Corrosion and durability of offshore steel water injection pipelines2015In: Ships and Offshore Structures, ISSN 1744-5302, E-ISSN 1754-212XArticle in journal (Refereed)
    Abstract [en]

    Carbon steel pipelines are widely used for injection of sea and other waters into oil and gas wells so as to increase the rate of recovery, particularly from mature fields. Internal corrosion usually is mild. However, cases of very aggressive channelling corrosion along the bottom of the pipeline have been observed. Practical experience and anecdotal observations have attributed this to microbiologically influenced corrosion even though extensive use is made of preventative measures including biocides, oxygen scavengers, corrosion and scale inhibitors, and pipeline pigging. Interpretation of data and observations for five water injection pipelines, made available by industry, indicate that microbiologically influenced corrosion may play a part in causing channelling corrosion but that the most likely cause is under-deposit corrosion under pipe debris that settles during periods of pipeline shut-downs and low water velocity. © 2015 Taylor & Francis

  • 45.
    Comanescu, Iulian
    et al.
    RISE, Swerea, Swerea KIMAB.
    Taxén, Claes
    RISE, Swerea, Swerea KIMAB.
    Assessment of MIC in carbon steel water injection pipelines2012In: Society of Petroleum Engineers - SPE International Conference and Exhibition on Oilfield Corrosion 2012, 2012, p. 227-234Conference paper (Refereed)
    Abstract [en]

    The present study compares corrosion mass loss and pit depth measurements on carbon steel corrosion coupons exposed under similar operating parameters, but with different biological consortia. One set of data were obtained from standard flush disc corrosion coupons used to monitor corrosion rates in a water injection pipeline on the North Sea continental shelf. The coupons were exposed on average for 6 months over 6 years operational time. These data are compared with published corrosion data of coupons exposed in abiotic district hot water systems from several power plants situated in Europe. The exposure time for these coupons was 9 months. Both systems were anoxic and in the same temperature range and are comparable. Observations regarding relationship between MIC and bacterial consortia, bacterial numbers and type, water quality and corrosion products are also made. The corrosion rate of the water injection pipeline is approximately 10 times higher compared with the corrosion rate in the abiotic district hot water system. It is concluded that the increased corrosion on the carbon steel coupons in the early stage is caused by MIC. This is also supported by the chemical and biological information available for the pipelines. The results reported here constitute the first step of an overall study to improve the level of understanding of the bacterial contribution to the total corrosion rates of carbon steel in water injection flowlines. Such understanding is expected to improve management and operational decision-making for practical control of corrosion in the field, by providing predictions of expected life time as a function of control of biotic consortia (e.g. through pigging, and biocide treatments). Further, it will facilitate decisions concerning choice of pipeline construction materials for future design. Copyright 2012, Society of Petroleum Engineers.

  • 46.
    Comanescu, Iulian
    et al.
    RISE, Swerea, Swerea KIMAB.
    Taxén, Claes
    RISE, Swerea, Swerea KIMAB.
    Life time assessment of offshore water injection pipelines as a function of microbiologically influenced corrosion2012Conference paper (Refereed)
    Abstract [en]

    Corrosion of water injection pipelines (WIP) in the oil and gas industry is a major issue involving potential premature life time predictions and unpredicted costs like periodic biocide treatment and pipeline pigging. This paper presents a part of a larger project concerned with improving understanding of the influence of bacterial activity on corrosion, as distinct from abiotic corrosion, in oil and gas transport systems for better management of pipeline systems. Observations are made concerning life time as a function of microbiologically influenced corrosion (MIC) risk and relationships between MIC, bacterial numbers and types, and water quality. Copyright © 2012 by the International Society of Offshore and Polar Engineers (ISOPE).

  • 47.
    Comanescu, Iulian
    et al.
    RISE, Swerea, Swerea KIMAB.
    Taxén, Claes
    RISE, Swerea, Swerea KIMAB.
    The possible influence of microorganisms on the patterns of corrosion seen in water injection pipelines2013Conference paper (Refereed)
    Abstract [en]

    A major problem for the management of oil and gas pipelines is corrosion influenced by microorganisms particularly, bacteria. The present study focuses on the influence particularly of the sulfate reducing bacteria on the internal corrosion of water injection pipelines. The research is based on reports from long-term observations of several water injections pipelines from the North Sea continental shelf. Observation data taken into consideration are pigging operation information, composition of corrosion products and their amount, corrosion rates and pipe geometry, identified biological consortia, water chemistry and process parameters. Observations regarding water quality and mitigation methods are made also. The distribution of corrosion including pitting and 'features' along the pipeline as well as the localization of these in relation to the orientation of the surfaces, is considered. This includes different corrosion patterns along the pipeline and the relative severity of six o'clock corrosion. These observations are used to make correlation estimates between severity and location of corrosion and service history and the local environmental conditions, where this information is available. The correlations are used to develop a clearer view of the proportion of biocorrosion contributing to the total corrosion in water injection pipelines. Additionally, an assessment is made of the efficiency of mitigation procedures such as biocide treatments and pigging operations. The paper provides possible explanations for different rates and spatial patterns of corrosion for water injection pipelines. © 2013 by NACE International.

  • 48.
    Danielsson, Mats
    RISE, Swerea, Swerea KIMAB.
    A stress update algorithm for constitutive models of glassy polymers2013In: International Journal for Computational Methods in Engineering Science and Mechanics, ISSN 1550-2287, E-ISSN 1550-2295, Vol. 14, no 4, p. 336-342Article in journal (Refereed)
    Abstract [en]

    A semi-implicit stress update algorithm is developed for the elastic-viscoplastic behavior of glassy polymers. The case of near rate-insensitivity is addressed, and the stress update algorithm is designed to handle this case robustly. A consistent tangent stiffness matrix is derived based on a full linearization of the internal virtual work. The stress update algorithm and (a slightly modified) tangent stiffness matrix are implemented in a commercial finite element program. The stress update algorithm is tested on a large boundary value problem for illustrative purposes. © 2013 Copyright Taylor and Francis Group, LLC.

  • 49.
    Danielsson, Mats
    et al.
    RISE, Swerea, Swerea KIMAB.
    Gårdstam, Johannes
    RISE, Swerea, Swerea KIMAB.
    Temperature dependent material properties of MaterialA used for quenching simulations2012Report (Refereed)
    Abstract [en]

    This report describes the experimental and computational programs that were used to extract material properties required for finite-element-based quenching simulations. Several metallurgical phases appear prior to, during, and after the quenching operation. The experimental program was designed so as to provide both temperature-dependent thermal and temperature-dependent elastic-plastic material properties for every appearing phase. One thermal property, enthalpy, was calculated using computational thermodynamics. In addition to material properties, metallurgical transformations (diffusion-governed and diffusionless) were quantified experimentally. The obtained data in this work was used to calibrate material models and models for phase transformation kinetics in the finite element software Sysweld.

  • 50.
    Doostmohammadi, H.
    et al.
    KTH.
    Jönsson, P.G.
    KTH.
    Komenda, Jacek
    RISE, Swerea, Swerea KIMAB.
    Hagman, S.
    Ovako Bar.
    Inclusion characteristics of bearing steel in a runner after ingot casting2010In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 81, no 2, p. 142-149Article in journal (Refereed)
    Abstract [en]

    In the uphill teaming method of ingot casting molten metal from the ladle goes into the runner system, which feeds one or several ingot moulds. This method is still important for production of bearing steel. In order to make clean steel, which has a controlled amount of inclusions, good understanding of inclusions characteristics is necessary. In this work non-metallic inclusions of steel left in the runner part of an ingot casting system were studied. Inclusion type, size, and morphology were the main focus of this study. A scanning electron microscope (SEM) was used to assess inclusion size and morphology. The chemical composition of inclusions was determined by SEM equipped with EDS. An automated program called 'INCAFeature' was used to collect statistics of inclusion characteristics. Based on the statistical analysis of inclusion composition, four types of inclusions including oxides, sulfides, carbonitrides and complex inclusions were defined. The inclusion characteristics in the runner were also compared to literature data of inclusions found in ladle and mould samples. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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