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  • 1.
    Ahlström, Johan
    et al.
    RISE., Swerea, KIMAB.
    Tidblad, Johan
    RISE., Swerea, KIMAB. RISE - Research Institutes of Sweden (2017-2019), Material och produktion, KIMAB.
    Sederholm, Bror
    RISE., Swerea, KIMAB.
    Wadsö, L.
    Lund University, Sweden.
    Influence of chloride and moisture content on steel rebar corrosion in concrete2016Ingår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 67, nr 10, s. 1049-1058Artikel i tidskrift (Refereegranskat)
    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, Yousef
    et al.
    KTH Royal Institute of Technology, Sweden.
    Viklund, Peter
    RISE., Swerea, KIMAB.
    Henderson, Pamela J.
    Vattenfall, Sweden.
    The analysis of furnace wall deposits in a low-NOx waste wood-fired bubbling fluidised bed boiler2012Ingår i: VGB PowerTech, ISSN 1435-3199, Vol. 92, nr 12, s. 96-100Artikel i tidskrift (Refereegranskat)
    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 materials2015Ingår i: European Corrosion Congress, EUROCORR 2015, Austrian Society for Metallurgy and Materials (ASMET) , 2015Konferensbidrag (Refereegranskat)
  • 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-white2016Ingår i: Procedia CIRP, Elsevier B.V. , 2016, s. 618-623Konferensbidrag (Refereegranskat)
    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 surfaces2014Ingår i: Advances in Polymer Science, ISSN 0065-3195, E-ISSN 1436-5030, Vol. 256, s. 1-24Artikel i tidskrift (Refereegranskat)
    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 analysis2012Ingår i: Yejin Fenxi/Metallurgical Analysis, ISSN 1000-7571, Vol. 32, nr 4, s. 1-5Artikel i tidskrift (Refereegranskat)
    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 development2013Ingår i: Yejin Fenxi/Metallurgical Analysis, ISSN 1000-7571, Vol. 33, nr 1, s. 7-12Artikel i tidskrift (Refereegranskat)
    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 waves2015Ingår i: 2015 IEEE International Ultrasonics Symposium, IUS 2015, Institute of Electrical and Electronics Engineers Inc. , 2015Konferensbidrag (Refereegranskat)
    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.
    Cassagne, Thierry B.
    et al.
    Total EP, France.
    Peultier, Jérome
    ArcelorMittal, France.
    Le Manchet, Sandra
    ArcelorMittal, France.
    Duret, Claude
    RISE., Swerea, KIMAB.
    An update on the use of duplex stainless steels in sour environments2012Ingår i: NACE - International Corrosion Conference Series, 2012, Vol. 4, s. 3041-3055Konferensbidrag (Refereegranskat)
    Abstract [en]

    Since the early days of production of the Lacq sour field in the South West of France, where early duplex stainless steel grades were used on wellheads and valves these alloys have been used extensively in the upstream Oil and Gas industry for sour applications. It is known that these alloys have a limited resistance in H 2S containing production environments as given in the NACE MR0175/ISO 15156 Standard. However these limits are conservative because they consider a low pH and high chloride content at the same time, a situation rarely encountered in service. Temperature is an additional parameter with a complex influence which may depend on the other parameters. This topic is not new and several literature reviews have already been published on this subject over the years. Unlike these past reviews this paper aims at summarizing the sulfide stress cracking and stress corrosion cracking resistance of commonly used duplex stainless steels in sour media under more relevant and realistic operating conditions. The goal is to give an overview of the latest available knowledge on the subject including selected relevant literature data, service experience and new laboratory data.

  • 10.
    Cassagne, Thierry B.
    et al.
    Total EP, France.
    Thierry, Dominique
    RISE., Swerea, KIMAB.
    Larché, Nicolas
    RISE., Swerea, KIMAB.
    Kivisäkk, Ulf
    Sandvik Material Technology, Sweden.
    Eidhagen, Josefin
    Sandvik Material Technology, Sweden.
    Mehus, L.
    Aker Subsea, Norway.
    Van Thoor, Karin
    Aker Subsea, Norway.
    Long term corrosion testing and monitoring of oxygen and corrosion potential in an umbilical design2012Ingår i: NACE - International Corrosion Conference Series, 2012, Vol. 2, s. 1096-1108Konferensbidrag (Refereegranskat)
    Abstract [en]

    Subsea umbilicals are used for control and operation of subsea oil and gas production facilities. Typically an umbilical consists of steel tubes, electrical cables, fiber optic cables, weight or strength elements and fillers. Super duplex stainless steel tube material has been used for almost 20 years within the umbilical industry. However, a recent failure on two orbital welds of 25Cr super duplex of an umbilical installed in the South China Sea was reported. From these results some umbilical end users recommended the use of thermoplastic coating to avoid crevice corrosion on 25Cr super duplex stainless steel above 20°C. However, this limit is based on results obtained for super duplex stainless steel in aerated natural seawater and very little is known on the micro-environment formed by the confined seawater between metallic tubes and polymer matrix of an umbilical. This work reports corrosion potential and oxygen content measurements in the confined zone between the metallic tubes and the polymer matrix of an umbilical. These measurements were performed using micro-electrodes on a 2 meter long real umbilical at 30°C in heated natural seawater. From the measurements, it is shown that the oxygen content in the confined zone is rapidly consumed probably due to the passive current on the stainless steel tubes and then remains below 2 ppm over one year exposure period. From the open-circuit potential measurements performed in the confined zone, it is clear that the open circuit potential remained below -150 mV/AgCl. This translates an absence of electrochemical effect of the biofilm in the confined zone. Visual and metallographic examinations of the tubes after exposure confirmed the results obtained by the microelectrodes and clearly indicate that no corrosion initiation occurred on superduplex stainless steel (base metal and welds) under these experimental conditions. The results are discussed in view of the validity of corrosion tests performed under aerated conditions and the need of further developments of new testing procedures to represent the confined situation in the umbilical design.

  • 11.
    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 Mn3Ni20P62016Ingår i: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 237, s. 343-348Artikel i tidskrift (Refereegranskat)
    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.

  • 12.
    Claesson, Erik
    et al.
    RISE., Swerea, KIMAB.
    Rod, Olivier
    RISE., Swerea, KIMAB.
    The effect of alloying elements on the corrosion resistance of brass2016Ingår i: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 32, nr 17, s. 1794-1803Artikel i tidskrift (Refereegranskat)
    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.

  • 13.
    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 gasifier2016Ingår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 67, nr 9, s. 939-951Artikel i tidskrift (Refereegranskat)
    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.

  • 14.
    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 boilers2016Ingår i: Materials at High Temperature, ISSN 0960-3409, E-ISSN 1878-6413, Vol. 33, nr 6, s. 587-595Artikel i tidskrift (Refereegranskat)
    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.

  • 15.
    Eman, Jesper
    et al.
    RISE., Swerea, SICOMP.
    Mannberg, Peter
    RISE., Swerea, SICOMP.
    Andersson, P
    RISE., Swerea, KIMAB.
    Thermal conductivity of thermosetting composite materials2012Konferensbidrag (Refereegranskat)
    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.

  • 16.
    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 stress2012Ingår i: HTM - Haerterei-Technische Mitteilungen, ISSN 0341-101X, Vol. 67, nr 3, s. 179-187Artikel i tidskrift (Refereegranskat)
    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. 

  • 17.
    Fahlström, Karl
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Material och produktion, 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 steel2015Ingår i: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 27, nr S2, artikel-id S29011Artikel i tidskrift (Refereegranskat)
    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. 

  • 18.
    Fahlström, Karl
    et al.
    RISE., Swerea, KIMAB. RISE - Research Institutes of Sweden (2017-2019), Material och produktion, 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 steels2016Ingår i: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 28, nr 2, artikel-id 022426Artikel i tidskrift (Refereegranskat)
    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.

  • 19.
    Frisk, Karin
    et al.
    RISE., Swerea, KIMAB.
    Borggren, Ulrika
    SSAB, Sweden.
    Precipitation in Microalloyed Steel by Model Alloy Experiments and Thermodynamic Calculations2016Ingår i: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 47, nr 10, s. 4806-4817Artikel i tidskrift (Refereegranskat)
    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. 

  • 20.
    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 simulations2016Ingår i: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Konferensbidrag (Refereegranskat)
    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.

  • 21.
    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 HIP2016Ingår i: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Konferensbidrag (Refereegranskat)
    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.

  • 22.
    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 treatment2016Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 163, nr 7, s. C377-C385Artikel i tidskrift (Refereegranskat)
    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. 

  • 23.
    Gurell, J.
    et al.
    RISE., Swerea, KIMAB.
    Bengtson, Arne
    RISE., Swerea, KIMAB.
    Falkenström, Magnus
    RISE., Swerea, KIMAB.
    Hansson, B. A. M.
    RISE., Swedish ICT, Acreo.
    Laser induced breakdown spectroscopy for fast elemental analysis sorting of metallic scrap pieces using certified reference materials2012Ingår i: Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 74, s. 46-50Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 24.
    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 batteries2016Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 163, nr 8, s. A1790-A1797Artikel i tidskrift (Refereegranskat)
    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.

  • 25.
    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 connectors2016Ingår i: ICEC 2016 - 28th International Conference on Electric Contacts, Heriot-Watt University , 2016, s. 87-92Konferensbidrag (Refereegranskat)
    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.

  • 26.
    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-oes2015Ingår i: Proceedings Euro PM 2015: International Power Metallurgy Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2015Konferensbidrag (Refereegranskat)
    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.

  • 27.
    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 steel2016Ingår i: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 60, nr 2, s. 233-245Artikel i tidskrift (Refereegranskat)
    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. 

  • 28.
    Hosseini, Vahid
    et al.
    University West, Sweden; Innovatum AB, Sweden.
    Wessman, Sten
    RISE., Swerea, KIMAB. RISE - Research Institutes of Sweden (2017-2019), Material och produktion, 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 steel2016Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 98, s. 88-97Artikel i tidskrift (Refereegranskat)
    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.

  • 29.
    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 coating2015Ingår i: 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, s. 535-540Konferensbidrag (Refereegranskat)
    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.

  • 30.
    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 temperatures2016Ingår i: Ultrasonics, ISSN 0041-624X, E-ISSN 1874-9968, Vol. 69, s. 268-272Artikel i tidskrift (Refereegranskat)
    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. 

  • 31.
    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 Application2016Ingår i: Procedia CIRP, Elsevier B.V. , 2016, s. 271-274Konferensbidrag (Refereegranskat)
    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.

  • 32.
    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 developments2016Ingår i: AGMA 2016 - Fall Technical Meeting, AGMA American Gear Manufacturers Association , 2016Konferensbidrag (Refereegranskat)
    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.

  • 33.
    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 condition2016Ingår i: Materials Science Forum, 2016, Vol. 879, s. 990-995Konferensbidrag (Refereegranskat)
    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.

  • 34.
    Le Calvé, Philippe
    et al.
    DCNS, France.
    Pautasso, Jean Pierre
    Générale de l'Armement, France.
    Le Bozec, Nathalie
    RISE., Swerea, KIMAB.
    Influence of UHP waterjetting on shop-primed steel in new construction, Part 32012Ingår i: Journal of Protective Coatings and Linings, ISSN 8755-1985, Vol. 29, nr 8, s. 42-53Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ultra-high-pressure (UHP) waterjetting is becoming more common for coatings on steel structures. An effort was made to design an appropriate welded sample, including a mixed zone at the periphery of the weld seam cleaned by UHP waterjetting to get a cleanliness DHP4. Three different paint systems were applied on the various panel design and roughnesses, and they were exposed to cyclic corrosion tests and natural weathering. Two designs of test panels were considered, flat panels and welded panels. The flat panels were then cleaned by UHP waterjetting on only one side, to treatment degree DHP1, light cleaning according to NF T 35-520 standard. The corrosion performance of the paint systems as a function of surface preparation was carried out in the laboratory. No degradation such as blistering, rusting, cracking, and chalking was observed on any of the paint systems. However, a loss of brightness was seen on S2 paint systems.

  • 35.
    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 components2016Ingår i: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Konferensbidrag (Refereegranskat)
    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.

  • 36.
    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 Binder2016Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 28, s. 18097-18106Artikel i tidskrift (Refereegranskat)
    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.

  • 37.
    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 steels2015Ingår i: Proceedings Euro PM 2015: International Power Metallurgy Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2015Konferensbidrag (Refereegranskat)
    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.

  • 38.
    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 material2016Ingår i: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Konferensbidrag (Refereegranskat)
    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.

  • 39.
    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 technique2016Ingår i: Protection of Metals and Physical Chemistry of Surfaces, ISSN 2070-2051, Vol. 52, nr 5, s. 936-946Artikel i tidskrift (Refereegranskat)
    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.

  • 40.
    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 microbiota2014Ingår i: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 30, nr 3, s. 281-297Artikel i tidskrift (Refereegranskat)
    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. 

  • 41.
    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 meter2016Ingår i: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Konferensbidrag (Refereegranskat)
    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.

  • 42.
    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 pressing2016Ingår i: World PM 2016 Congress and Exhibition, European Powder Metallurgy Association (EPMA) , 2016Konferensbidrag (Refereegranskat)
    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.

  • 43.
    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 slags2016Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 56, nr 2, s. 264-273Artikel i tidskrift (Refereegranskat)
    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.

  • 44.
    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: Steels2016Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 56, nr 2, s. 274-281Artikel i tidskrift (Refereegranskat)
    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.

  • 45.
    Nazarov, Andrej
    et al.
    RISE., Swerea, KIMAB.
    Le Bozec, Nathalie
    RISE., Swerea, KIMAB.
    Thierry, Dominique
    RISE., Swerea, KIMAB.
    Le Calvé, Philippe
    DCNS, France.
    Pautasso, Jean Pierre
    Direction Générale de L'Armement, France.
    Scanning kelvin probe investigation of corrosion under thick marine paint systems applied on carbon steel2012Ingår i: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 68, nr 8, s. 720-729Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The scanning Kelvin probe (SKP) is a non-destructive technique for measuring the surface distribution of the Volta potential with a high spatial resolution of a few tens of micrometers. The SKP technique allows in situ studies of the localized corrosion processes under atmospheric weathering conditions, on metal surfaces, or underneath organic coatings. In the present study, the SKP technique was used to follow the kinetics of underpaint corrosion from a defect applied on steel coated with thick marine paint systems (0.4 mm to 0.5 mm) as a function of exposure time in an accelerated corrosion test. Three different paint systems were investigated. In addition, the influence of surface cleanliness in terms of salt concentration on a steel substrate prior to paint application was investigated using the SKP technique. The results showed the high efficiency of the SKP technique for early corrosion evaluation under thick paints on steel substrate.

  • 46.
    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 microscope2015Ingår i: Protection of Metals and Physical Chemistry of Surfaces, ISSN 2070-2051, Vol. 51, nr 3, s. 347-359Artikel i tidskrift (Refereegranskat)
    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.

  • 47.
    Nazarov, Andrej P.
    et al.
    RISE Research Institutes of Sweden, Material och produktion.
    Diler, Erwan
    RISE Research Institutes of Sweden, Material och produktion.
    Persson, Daniel Pergament
    RISE., Swerea, KIMAB.
    Thierry, Dominique
    RISE Research Institutes of Sweden, Material och produktion.
    Electrochemical and corrosion properties of ZnO/Zn electrode in atmospheric environments2015Ingår i: Journal of Electroanalytical Chemistry, ISSN 1572-6657, Vol. 737, s. 129-140Artikel i tidskrift (Refereegranskat)
    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.

  • 48.
    Nazarov, Andrej P.
    et al.
    RISE., Swerea, KIMAB.
    Romano, Anne Pascale
    University of Mons, Belgium.
    Fedel, Michele
    University of Trento, Italy.
    Deflorian, Flavio
    University of Trento, Italy.
    Thierry, Dominique
    RISE., Swerea, KIMAB.
    Olivier, Marie Georges Marjorie
    University of Mons, Belgium.
    Filiform corrosion of electrocoated aluminium alloy: Role of surface pretreatment2012Ingår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 65, s. 187-198Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Commercial Oxsilan, 3-aminopropyltriethoxysilane and sol-gel siloxane coatings were applied on AA6016 aluminium alloy before electrocoating. Standard filiform corrosion test demonstrated the pre-treatment role on the under-paint corrosion rate. All pre-treatments increase the coating adhesion in water electrolyte (EIS). Anodic undermining is the mechanism of the coatings de-adhesion (SKP). Electromotive force (difference in potentials of defect-surrounding interface) and interface ability to promote the chloride migration are rate-determining factors of the filiform corrosion. Contrary to other pre-treatments, the aminosiloxane decreases the interfacial potential, facilitates the chlorides migration and leads to anodic de-adhesion of large coated areas (Tof-SIMS and EDXS).

  • 49.
    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.
    Taxén, 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 stability2016Ingår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 110, s. 71-81Artikel i tidskrift (Refereegranskat)
    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.

  • 50.
    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 bodies2016Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 306, s. 439-447Artikel i tidskrift (Refereegranskat)
    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

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