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  • 301.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Dubois, Francois
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Kouril, Milan
    Institute of Chemical Technology, Czech Republic.
    Scheffel, Bert
    Fraunhofer, Germany.
    Degres, Yves
    NKE, France.
    Jouannic, M.
    NKE, France.
    Taube, Michelle
    National Museum of Denmark, Denmark.
    Dubus, Michel
    Centre de Recherche et de Restauration des Musées de France, France.
    Hubert, Vera
    Swiss National Museum, Switzerland.
    Thierry, Doinique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Application of automated corrosion sensors for real-time monitoring in atmospheres polluted with organic acids2011In: 18th International Corrosion Congress 2011, 2011, p. 1477-1484Conference paper (Refereed)
    Abstract [en]

    Loggers for continuous measurement of the corrosion rate of metals under atmospheric conditions were developed. The electronic unit measures and records changes in the electrical resistance of a thin metal track applied on an insulating substrate. If the metal corrodes, the effective cross-sectional area of the track decreases and the electrical resistance increases. Part of the metal track is protected by an organic coating and, thus, serves as a reference to compensate for resistivity changes due to varying temperature. Sensors made of silver, copper, iron / steel, zinc, bronze and lead with sensitivities tailored to different environments are available. Thin film metal sensors with the metal track thickness from 50 to 800 nm were made by physical vapour deposition (PVD). Examples of the logger application for continuous measurements of metal corrosion rates in air are given. Due to the sensitivity of the measurement as high as 0.1 nm, in terms of corrosion depth, changes in air corrosivity were registered within tens of minutes or hours even in low-corrosive environments. At relative humidities from 15 to 80 % and at the temperature of 20 °C, it was used for monitoring in the air polluted with controlled amounts of formic and acetic acids at concentrations from 0-1590 and 0- 870 ppb, respectively. Gases in these concentrations were reported to be found in museums and other cultural heritage institutions and are expected to cause accelerated deterioration of metal objects. Threshold limits of the formic acid concentration in air at 80 % RH and at 20 °C causing changes in the classification of indoor air corrosivity according to ISO 11844-1 are given.

  • 302.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Iversen, Anna K.
    Outokumpu Stainless AB, Sweden.
    Taxen, Claes
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Low temperature stress corrosion cracking of stainless steels in the atmosphere in presence of chloride deposits2008In: NACE - Int. Corros. Conf. Ser., 2008, p. 084841-0848417Conference paper (Refereed)
    Abstract [en]

    Several cases of ceiling collapses and other failed elements have been reported in indoor swimming pool halls in the last two decades. The collapses were caused by stress corrosion cracking (SCC) of stainless steel fastening elements made of grades UNS S30400, S31600, or similar. It was shown that this phenomenon can occur under specific conditions beneath chloride deposits at temperatures as low as the room temperature. The aim of this study was to assess the application limits of different austenitic and duplex stainless steel grades subject to tensile stress and contaminated with chloride deposits in the atmosphere under non-washing conditions as a function of temperature (20-50 °C), relative humidity (15-70 % RH), and deposit composition. Austenitic stainless steel grades UNS S30400 and S31603 were susceptible to SCC in the presence of magnesium and calcium chlorides at temperatures from 30 °C and at low relative humidity. The tendency to SCC increased with increasing temperature and decreasing relative humidity. The corrosivity of salt at given exposure conditions decreased in the following order CaCl2 > MgCl2 > FeCl3 > NaCl. The corrosivity of chloride deposits was governed by the equilibrium chloride concentration in the surface electrolyte formed as a result of interaction of given chloride salt and air at given relative humidity. Threshold values of the minimum chloride concentration and relative humidity intervals leading to SCC at 30 and 40 °C were established for UNS S30400 and S31603. Duplex stainless steels S32101, S32304, S32205, and S32750 corroded selectively to the maximum depth of 380 μn. Austenitic stainless steels N08904 and S31254 showed no tendency to SCC.

  • 303.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Iversen, Anna K.
    Outokumpu Stainless AB, Sweden.
    Taxen, Claes
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Low-temperature stress corrosion cracking of stainless steels in the atmosphere in the presence of chloride deposits2009In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 65, no 2, p. 105-117Article in journal (Refereed)
    Abstract [en]

    Several cases of ceiling collapses and other failed elements have been reported in indoor swimming pool halls in the last two decades. The collapses were caused by stress corrosion cracking (SCC) of stainless steel fastening elements covered with chloride deposits at temperatures as low as room temperature. The goal of this study was to assess the application limits of different austenitic and austenitic-ferritic (duplex) stainless steels subject to tensile stress and contaminated with chloride deposits in atmospheric non-washing conditions as a function of temperature (20°C to 50°C), relative humidity (15% to 70% RH), and deposit composition. Austenitic stainless steels Type 304 (UNS S30400) and Type 316L (UNS S31603) were susceptible to SCC in the presence of magnesium and calcium chlorides at temperatures of 30°C and higher and at low relative humidity. The tendency to SCC increased with increasing temperature and decreasing relative humidity. The corrosivity of chloride deposits under given exposure conditions decreased in thefollowing order: calcium chloride (CaCl2) > magnesium chloride (MgCl2) > sodium chloride (NaCl). It was governed by the equilibrium chloride concentration in the surface electrolyte formed as a result of interaction of a given salt with water vapor in the air. Threshold values of the minimum chloride concentration and relative humidity intervals leading to SCC were established for Type 304 and Type 316L. Duplex stainless steels S32101 (UNS S32101), 2304 (UNS S32304), 2205 (UNS S32205), and 2507 (UNS S32750) were resistant to SCC but corroded selectively with the maximum depth of 200 μm. Austenitic stainless steels Type 904L (UNS N08904) and Type S31254 (UNS S31254) showed no tendency to SCC.

  • 304.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Kouril, Milan
    Institute of Chemical Technology, Czech Republic.
    Dubus, Michel
    Centre de Recherche et de Restauration des Musees de France, France.
    Taube, Michelle
    National Museum of Denmark, Denmark.
    Hubert, Vera
    Swiss National Museum, Switzerland.
    Scheffel, Bert
    Fraunhofer, Germany.
    Degres, Yves
    NKE, France.
    Jouannic, M.
    NKE, France.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Real-time monitoring of indoor air corrosivity in cultural heritage institutions with metallic electrical resistance sensors2013In: Studies in Conservation, ISSN 0039-3630, E-ISSN 2047-0584, Vol. 58, no 2, p. 117-128Article in journal (Refereed)
    Abstract [en]

    A system for continuous monitoring of atmospheric corrosivity has been developed. An electronic unit measures and records changes in the electrical resistance of a thin metal track applied on an insulating substrate. If the metal corrodes, the effective cross sectional area of the track decreases and the electrical resistance increases. Sensors made of silver, copper, iron/steel, zinc, lead, tin, aluminium, bronze, and brass at thicknesses from 50 nm to 250 μm were tailored for environments with different corrosivities. The developed technology proved capable of providing high sensitivity, allowing for real-time corrosion monitoring even in low-corrosive indoor cultural heritage facilities. Laboratory tests showed good reproducibility with the standard deviation of parallel measurements at less than ±20% for metals which corrode uniformly in the tested environments. Several examples selected from a broad testing programme in partner museums, libraries, and other institutions show successful applications of the logger system for characterization of air quality control in indoor locations, during transport and in temporary exhibitions; assessment of new buildings and storage facilities; and fundamental studies of optimal conservation and storage procedures. A first outline of a classification system for lead, which is particularly sensitive to the presence of carboxylic acids, is given. The technique has a large potential as an independent method for monitoring air quality in facilities displaying and storing valuable objects of cultural heritage.

  • 305.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Kouril, Milan
    Institute of Chemical Technology, Czech Republic.
    Hilbert, Lisbeth Rischel
    DTU Technical University of Denmark, Denmark.
    Degres, Yves
    NKE, France.
    Blazek, Vladimir J.
    Galvanotechna, Czech Republic.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Østergaard Hansen, Mikkel
    DTU Technical University of Denmark, Denmark.
    Real time corrosion monitoring in atmosphere using automated battery driven corrosion loggers2008In: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 43, no 2, p. 129-133Article in journal (Refereed)
    Abstract [en]

    A logger enabling continuous measurement of corrosion rate of selected metals in indoor and outdoor atmospheres has been developed. Principle of the measurement method is based on the increasing electrical resistance of a measuring element made of the material concerned as its cross-sectional area diminishes due to corrosion. Zinc, iron, copper and nickel sensors at several thicknesses are available. Sensitivity of the corrosion measurement varies from 1 to 10 nm depending on the type and thickness of the sensor. Changes in the air corrosivity can be thus detected within hours or even tens of minutes. The logger lifetime in medium corrosive environments is designed to be 2 years with full autonomy. Data on the sensor corrosion rate are available any time through GPRS connection or by a non-contact inductive reading without the need of retracting the logger from the exposure site.

  • 306.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Larche, Nicholas
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Vlot, M.
    Corus, The Netherlands.
    Goodwin, Frank E.
    IZA, USA.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Corrosion performance of Zn-Al-Mg coatings in open and confined zones in conditions simulating automotive applications2010In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 61, no 5, p. 412-420Article in journal (Refereed)
    Abstract [en]

    Panels coated by hot dipping with zinc (HDG), Zn-5Al (Galfan) and Zn-1.5Al- 1.5Mg coatings at different thicknesses were phosphated and painted on an industrial line. Crevice panels with non-painted bare parts modelling conditions in hem flanges, reference panels with open surfaces and formed non-painted panels were exposed to a cyclic accelerated automotive test. Zn-Al-Mg coatings with the thickness of 10 μ rovided similar or even better protection than HDG and Galfan at 20 mmin both confined and open configurations. In comparison to 10-μm HDG, the Zn-Al-Mg coating delayed red rust appearance in crevices by a factor of 2 and the maximal depth of corrosion in the steel substrate was by 42% lower. Confined areas were more corroded than open surfaces. For HDG, the time to red rust appearance dropped by 50-75%, corrosion attack in steel was from 3.5 to 7 times deeper and mass gain was about 2.3 times higher in crevices than on open surfaces. Corrosion of Zn-Al-Mg may be more affected by local environmental conditions created by the crevice configuration than for HDG. Red rust appearance on formed panels of 20-mm Galfan, 7-, 10- and 14-mm Zn- Al-Mg was delayed to 10-μm HDG by a factor of 2.8, 3.5, 3.8 and >4.5, respectively. No adverse effect of forming was noticed. The results indicate that 2- to 3-fold reduction of the coating thickness for Zn-Al-Mg alloy coatings in comparison to traditional HDG may be possible without compromising the corrosion performance.

  • 307.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Le Gac, Anne
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Le Manchet, Sandra
    ArcelorMittal, France.
    Lojewski, Christian
    ArcelorMittal, France.
    Fanica, Amelie
    ArcelorMittal, France.
    Johansson, Elisabeth
    Outokumpu Stainless, Sweden.
    Canderyd, Carolina
    Outokumpu Stainless, Sweden.
    Dupoiron, Francois
    Total Petrochemicals, France.
    Snauwaert, Tom
    Stolt Tankers, The Netherlands.
    Maas, Fleur
    Belgisch Instituut voor lastechniek, Belgium.
    Droesbeke, Benny
    Belgisch Instituut voor lastechniek, Belgium.
    Low-temperature stress corrosion cracking of austenitic and duplex stainless steels under chloride deposits2014In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 70, no 10, p. 1052-1063Article in journal (Refereed)
    Abstract [en]

    Corrosion performance of austenitic-ferritic (duplex) stainless steels UNS S32101, S32202, S32304, and S32205 and austenitic stainless steels UNS S30403 and S31603 was studied in the presence of chloride deposits simulating non-rinsing atmospheric conditions. The effect of temperature, relative humidity, concentration, and composition of the chloride deposits on the tendency for atmospheric, low-temperature, chloride-induced stress corrosion cracking (SCC), pitting, and selective corrosion was assessed using prestressed samples with a circular weld. In the presence of calcium chloride, SCC was observed at temperatures as low as 20°C and 30°C on the austenitic stainless steels UNS S30403 (Type 304L) and UNS S31603 (Type 316L), respectively. The only cases of SCC of tested duplex stainless steel grades were found at 70°C, which otherwise suffered mainly selective dissolution of the ferrite phase with one order lower depth of attack. The initiation of SCC and selective/pitting corrosion was governed by the equilibrium chloride concentration in a solution formed by contact with chloride-containing deposits and with air at a given relative humidity. Threshold levels of critical chloride concentrations, critical relative humidity in the presence of specific deposits, and maximum temperatures for safe applications of the studied grades were established.

  • 308.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Nazarov, Andrej
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Bexell, Ulf
    Dalarna University, Sweden.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Serak, Jan
    Institute of Chemical Technology, Czech Republic.
    Corrosion mechanism of model zinc-magnesium alloys in atmospheric conditions2008In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 50, no 8, p. 2216-2231Article in journal (Refereed)
    Abstract [en]

    Recently, superior corrosion properties of zinc coatings alloyed with magnesium have been reported. Corrosion behaviour of model zinc-magnesium alloys was studied to understand better the protective mechanism of magnesium in zinc. Alloys containing from 1 to 32 wt.% magnesium, pure zinc, and pure magnesium were contaminated with sodium chloride and exposed to humid air for 28 days. Composition of corrosion products was analyzed using infrared spectroscopy (FTIR), ion chromatography (IC), and Auger electron spectroscopy (AES). The exposure tests were completed with scanning Kelvin probe (SKP) and electrochemical measurements. Weight loss of ZnMg alloys with 1-16 wt.% magnesium was lower than that of pure zinc. Up to 10-fold drop in weight loss was found for materials with 4-8 wt.% Mg in the structure. The improved corrosion stability of ZnMg alloys was connected to the presence of an Mg-based film adjacent to the metal surface. It ensured stable passivity in chloride environment and limited the efficiency of oxygen reduction.

  • 309.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Nazarov, Andrej
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Olivier, Marie Georges Marjorie
    Polytechnique de Mons, Belgium.
    Vandermiers, Catherine
    Polytechnique de Mons, Belgium.
    Koberg, Dorothe
    BASF Coatings AG, Germany.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    The role of stress and topcoat properties in blistering of coil-coated materials2010In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 68, no 4, p. 328-333Article in journal (Refereed)
    Abstract [en]

    The effect of topcoat properties on the tendency of painted materials to blistering was studied. Six topcoats were applied on identical panels of hot-dip galvanized steel painted with a polyester primer. The tendency to blistering was assessed under the conditions of permanent condensation in a Q-panel condensation test at 60 °C. Internal tensile stress and stress development in organic coatings during temperature and relative humidity cycling were investigated by the cantilever curvature method. Although blisters originated from the metal/polymer interface, the extent of blistering was strongly influenced by the topcoat. Available data suggest that it may increase with the coating thickness, glass transition temperature (Tg) and thermal expansion properties. Connection was found between the internal tensile stress formed in topcoats during the paint film preparation and the extent of blistering. A hypothesis that stress-assisted interfacial bond hydrolysis was responsible for blister initiation is proposed. Other experiments suggested that local paint buckling over non-adherent sites can be caused by plastic deformation of the paint due to relief of compressive stress generated at elevated temperature or by ingress of water.

  • 310.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Nazarov, Andrej
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Stoulil, Jan
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Evaluation of the tendency of coil-coated materials to blistering: Field exposure, accelerated tests and electrochemical measurements2012In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 61, p. 92-100Article in journal (Refereed)
    Abstract [en]

    The tendency of coil-coated hot dip galvanized materials to blistering was investigated in accelerated tests and by electrochemical impedance spectroscopy. The best prediction of outdoor performance at a marine test site was obtained in the Q-panel condensation test (QCT) at 60 °C with the minimum testing time of 500. h. The ratio of the impedance modulus at 60 and 25 °C measured at a low frequency of 0.1. Hz correlated with the extent of blistering after outdoor exposures and accelerated tests. It is proposed that this parameter reflects the interaction of the polymer and the metal/polymer interface with water.

  • 311.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Persson, Dan
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Stoulil, Jan
    Institute of Chemical Technology in Prague, Czech Republic.
    Thierry, Domninique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Composition of corrosion products formed on Zn-Mg, Zn-Al and Zn-Al-Mg coatings in model atmospheric conditions2014In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 86, p. 231-238Article in journal (Refereed)
    Abstract [en]

    Formation of corrosion products on hot-dip galvanised steel. (HDG), Zn-5Al, Zn-11Al-3Mg-0.2Si, Zn-16Mg and Zn-1.5Al-1.5Mg with pre-deposited NaCl was followed in humid air at 20. °C. The alloyed coatings showed an improvement in mass loss by a factor of 4-7 to HDG. Corrosion products on the alloyed coatings contained twice as much carbonates than those formed on HDG. Magnesium dissolved preferentially, and aluminium-enriched phases were the most stable. Magnesium buffered the pH at cathodic sites, thus hindering the formation of zinc oxide and inhibiting the oxygen reduction. Magnesium products at the metal/corrosion product interface might also have an inhibiting effect.

  • 312.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Taube, Michelle
    National Museum of Denmark, Denmark.
    Dubois, Francois
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Application of automated electrical resistance sensors for measurement of corrosion rate of copper, bronze and iron in model indoor atmospheres containing short-chain volatile carboxylic acids2014In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 87, p. 376-382Article in journal (Refereed)
    Abstract [en]

    The corrosion rate of copper and bronze Cu-8. wt.%Sn increased rapidly when the concentration of formic or acetic acid in air reached about 300. ppb at 80% relative humidity (RH) and a temperature of 20. °C. It decreased slowly during the several days after pollutant removal due to the slow rate of pollutant desorption from the metal surfaces. Corrosion of these metals was barely affected by the acids at RH up to 60%. For iron, the critical concentration of formic acid in air which led to surface activation at 80% RH was between 1000 and 1590. ppb.

  • 313.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Corrosion inhibition by chromate at defects of organic coatings2004In: EUROCORR 2004 - European Corrosion Conference: Long Term Prediction and Modelling of Corrosion, 2004Conference paper (Refereed)
    Abstract [en]

    Chromate is known as one of the most effective inhibitors for a wide range of technically important metals and alloys, particularly aluminum alloys and galvanized zinc surfaces protecting steel against atmospheric corrosion. The very good protective ability of inhibiting systems with chromate became the subject of intensive research in recent years. The major reason of the research activity is the environmentally driven effort to limit or even diminish the usage of chromate because of its toxicity and possible human carcinogenity. The understanding of the mechanism of the chromate inhibition is believed to be essential in formulating the alternative inhibiting systems, which should provide at least comparable efficiency. The study was focused on the corrosion inhibition by chromate in primer coatings applied on hot-dip galvanized steel (HDG) under atmospheric weathering conditions, particularly at defected areas of the coatings such as scribes or cut-edges. The kinetics of chromate release from organic coatings to solution, chromate mobility ("throwing power") at defected areas and the composition and some properties of the forming protective layer on the zinc surface have been studied. To characterize the composition of the surface layers on zinc, Fourier Transformed Infra-Red (FTIR), Energy Dispersive X-ray (EDX) and X-ray Absorption Near Edge Structure (XANES) techniques were applied. The composition of solutions was analyzed by Ion Chromatography (IC). Based on the experiments and published results of other authors, a mechanism of the inhibition by chromate in the system pigmented coating / water / zinc in atmospheric conditions was proposed. After establishing contact between the coating and water, hexavalent chromium starts to dissolve rapidly and releases from the coating in the form of chromate, CrO 4 2-, dichromate, Cr 2O 7 2-, or bichromate, HCrO 4 -, according to actual pH and Cr(VI) concentration. The released ions are in neutral solutions stable with a minimal bias to be reduced to Cr(III). The ions of hexavalent chromium are transported toward unprotected bare zinc and adsorbed on the surface. Moreover, Cr(VI) is able to seek active, or formerly active, corrosion sites, e.g. corrosion pits, where it is preferentially adsorbed. On the zinc surface, chromate is partly reduced to Cr(III). The film formed on zinc in the presence of chromate in solution is composed mainly of Cr(III), with a smaller extent of Cr(VI). Further consumption of chromate available in the solution is slow and controlled by the aggressiveness of the solution rather than by the chromate concentration. The film formation and/or presence lead to a highly efficient inhibition of zinc corrosion, probably due to decrease in the oxygen reduction rate.

  • 314.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Mobility and mode of inhibition of chromate at defected areas of organic coatings under atmospheric conditions2004In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 60, no 12, p. 1122-1133Article in journal (Refereed)
    Abstract [en]

    The ability of chromate as an anticorrosive pigment incorporated into primer coatings to inhibit the corrosion of galvanized steel has been studied using cell modeling conditions at defects of painted sheets. The experiments were performed at different temperatures (4, 22, and 40° C) and chloride concentrations (1 mmol/L and 10 mmol/L) with coatings releasing from 20 mg/m2 to 100 mg/m2 chromate per 48 h. After 1 h to 48 h of exposure, the solutions were analyzed by ion chromatography (IC) and the metal samples were studied using Fourier transformed infrared (FTIR), energy-dispersive x-ray (EDX), and x-ray absorption near-edge structure (XANES) spectroscopy. The XANES measurements detected the presence of a Cr(III)/Cr(VI) layer containing approximately 15% of Cr(VI) on the initially bare zinc surface. Corrosion of the samples exposed with the chromated primers was clearly inhibited in comparison with blank samples, with an inhibition efficiency ranging from 50% to 95% according to the exposure conditions. Thus, the results showed that chromate was transported from the pigmented primer to the bare metal surface and formed a protective layer on it. Moreover, an enrichment of the pit centers with chromium wasfound with EDX, suggesting the ability of chromate to seek the active, or formerly active, corrosion sites and preferentially adsorb at these locations. The extent of corrosion deterioration of the samples and chromate consumption was regarded with respect to temperature, chloride concentration, total amount of released chromate, and the kinetics of the release. The developed experimental technique was tested on a vanadate system as well. The experimental setup proved to be a simple and efficient tool for future testing of paints, inhibitors, materials, or aggressiveness of environment, as well as for fundamental studies. © 2004, NACE International.

  • 315.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Prediction of easy-to-clean properties of coil coated materials in field conditions2011In: 18th International Corrosion Congress 2011, 2011, p. 984-990Conference paper (Refereed)
    Abstract [en]

    The application of easy-to-clean coatings grows in polluted urban and industrial areas and paint suppliers and coil coaters develop coil coated products with improved easy-to-clean properties. However, there is not any standardized procedure allowing for prediction of the degradation of the easy-to-clean properties in service conditions yet. Dirt retention is usually tested in laboratory conditions using a carbon slurry test, which exists in many modifications. The aim of this study was to compare results of several carbon slurry tests to outdoor exposures at four sites representing different climates and pollution characteristics for a large number of easy-to-clean and reference materials in order to propose the optimal testing procedure. Six procedures of the carbon slurry test were used differing in the type of carbon black, drying time after the slurry application, baking temperature and baking time. The results were correlated to dirt pick up and dirt retention measured after 3, 6, 12 and 24 months of exposure at a non-polluted marine site, non-polluted marine tropical site and two sites with high industrial pollution and dirt deposition. A procedure of the carbon slurry test providing the best prediction of outdoor performance was indentified. It is characterized by a prolonged baking time. Still, the acquired data suggest that a short-term 3-months exposure at a site with high industrial pollution was more reliable for prediction of dirt pick up and dirt retention after 2 years of exposure than the best performing carbon slurry test.

  • 316.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Hagström, Joakim
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Persson, Daniel
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Fuertes, Nuria
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Lindberg, Fredrik
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Taxen, Claes
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Serak, Jan
    Institute of Chemical Technology, Czech Republic.
    Relationship between corrosion performance and microstructure of Zn-AI and Zn-AI-Mg model alloys2015In: European Corrosion Congress, EUROCORR 2015, Austrian Society for Metallurgy and Materials (ASMET) , 2015, p. 511-522Conference paper (Refereed)
    Abstract [en]

    Zn-5wt.%AI and Zn-3wt.%AI-2wt.%Mg model alloys were cast and heat treated in order to obtain specimens with distinct microstructure and identical chemical composition. The microstructure was characterized in detail using scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX) and x-ray diffraction spectroscopy (XRD) to identify chemical composition, size and distribution of present phases. Mass loss of samples with different microstructure and identical chemical composition subjected to a cyclic corrosion test and a test under non-rinsing conditions differed by a factor of up to two. Some model alloys showed better corrosion performance compared to commercial coatings with similar composition tested in parallel. This indicates that microstructure modification can improve the corrosion performance of industrial zinc alloy coatings. The mechanism is discussed based on measurements of corrosion stability of individual phases, preferential corrosion, composition and stability of corrosion products, dc electrochemical characteristics and infrared absorption spectroscopy (IRRAS) experiments.

  • 317.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Kouril, Milan
    Institute of Chemical Technology, Czech Republic.
    Degres, Yves
    NKE, France.
    Automated corrosion loggers for corrosion monitoring in the atmosphere2008In: NACE - International Corrosion Conference Series, 2008, p. 082961-082966Conference paper (Refereed)
    Abstract [en]

    The information on actual corrosivity of the environment is crucial for efficient corrosion protection since it enables operators to take immediate counter measures against accelerating corrosion, decreasing thereby the corrosion costs. Atmospheric corrosion sensors have been developed to provide continuous measurement of the corrosion rate of steel, zinc, copper, and nickel in air. The measurement method is based on the increasing electrical resistance of a measuring element made of the material concerned as its cross sectional area diminishes due to corrosion. Data on the sensor corrosion rate are available any time without the need to retract the logger from the exposure site. They can be downloaded through the General Packet Radio Service (GPRS) connection or by means of a non-contact inductive reading. The electronic logger has dimensions of 100×65×37 mm and the weight is about 180 grams. Therefore, the logger can be placed virtually anywhere. The lifetime of the monitoring system in medium-corrosive environments is designed to be 2 years with full autonomy. Metal sensors are available at several thicknesses of metal tracks according to the anticipated level of air corrosivity and required sensitivity of measurement. Sensitivity of the corrosion measurement varies from 1 to 10 nm depending on the type and thickness of the sensor. Changes in the air corrosivity can be usually detected within several hours or even tens of minutes.

  • 318.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Olsson, Mikael Kharrazi
    Dalarna University, Sweden.
    Bexell, Ulf
    Dalarna University, Sweden.
    Effect of chloride-to-chromate ratio on the protective action of zinc surface films under atmospheric weathering conditions2007In: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 63, no 3, p. 258-267Article in journal (Refereed)
    Abstract [en]

    The formation and the corrosion protection of newly formed chromium-rich layers on bare zinc surfaces were studied to model the conditions in defected areas of both organic and conversion chromate coatings that are in contact with water environments contaminated with different amounts of chloride ions. Composition of the layers was identified with Fourier transformed infrared spectroscopy (FTIR), x-ray absorption near-edge structure (XANES), and secondary ion mass spectroscopy (SIMS). The presence of chloride in the range from 0.06 mM to 1,000 mM in the chromate treating solution had almost no effect on the amount of chromate adsorbed on zinc. Three independent technique showed that a more than 4-order increase in chloride concentration results in the drop of the chromate content in the surface film only by 20% to 25%. Cr(VI)-to-total Cr surface ratio was close to 0.3 and constant under present experimental conditions. More chromium was detected in the outer region of the film, whereas chloride accumulated in the inner region. As a result of the linear increase of the surface chloride concentration with the chloride concentration in the chromate treating solution, the chloride-to-chromate surface molar ratio increased sharply. The rate of reduction of Cr(VI) to Cr(III) and the corrosion rate of zinc exposed to atmospheric weathering conditions increased significantly with the chloride-to-chromate ratio. The chromate coatings showed good stability and a high level of corrosion protection, up to the ratio of approximately 2. It represented a threshold value below which relatively low rates of the chromate reduction and zinc corrosion were observed, since the significant part of the chloride ions was inactivated in the first hours of exposure by the formation of insoluble corrosion products. A negative effect of the increasing chloride-to-chromate surface molar ratio on corrosion can be seen in the increasing ability to reduce oxygen on the zinc surface measured by the scanning Kelvin probe (SKP) technique. Inhibition of the cathodic reaction by chromate was less effective at higher ratios.

  • 319.
    Prosek, Tomas
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Taxén, Claes
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Maixner, Jaroslav
    Institute of Chemical Technology, Czech Republic.
    Effect of cations on corrosion of zinc and carbon steel covered with chloride deposits under atmospheric conditions2007In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 49, no 6, p. 2676-2693Article in journal (Refereed)
    Abstract [en]

    The effect of sodium, calcium, and magnesium chlorides deposited on zinc and carbon steel surfaces was studied under atmospheric conditions. The cations strongly affected the corrosion rate of zinc, whereas they had a significantly lower impact on the corrosion of carbon steel. The corrosivity of cations of chloride salts for zinc increased in order of Mg2+ < Ca2+ < Na+. The higher corrosion resistance of zinc treated with calcium and magnesium chlorides was connected to prevention of formation of hydrozincite during zinc exposure in wet air. It was observed that zinc weight loss and the carbonate to simonkolleite ratio in corrosion products were correlating. The principal protective effect of bivalent cations can be seen in the decrease of pH of the surface electrolyte, which was caused by hydrolysis of such cations and subsequent formation of simonkolleite that blocked the cathodic sites.

  • 320.
    Qiu, P.
    et al.
    Royal Institute of Technology.
    Persson, Dan
    RISE, Swerea, Swerea KIMAB.
    Leygraf, C.
    Royal Institute of Technology.
    Initial atmospheric corrosion of zinc induced by carboxylic acids: A quantitative in situ study2009In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 156, no 12, p. C441-C447Article in journal (Refereed)
    Abstract [en]

    The initial atmospheric corrosion of zinc induced by formic acid, acetic acid, and propionic acid has been followed in situ with infrared reflection absorption spectroscopy (IRAS). An optical model was applied to quantify the IRAS data, which enabled the absolute amounts of the two main species detected, ZnO and zinc carboxylate (mainly hydrated or hydroxyl zinc carboxylate), to be derived. The formation rate of zinc carboxylate increases as propionic

  • 321.
    Qiu, P.
    et al.
    Royal Institute of Technology.
    Persson, Dan
    RISE, Swerea, Swerea KIMAB.
    Leygraf, C.
    Royal Institute of Technology.
    Initial oxidation of zinc induced by humidified air: A quantified in situ study2009In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 156, no 3, p. C81-C86Article in journal (Refereed)
    Abstract [en]

    A multianalytical approach with in situ capability has been used to explore the initial oxidation of zinc in air with 90% relative humidity at 20°C. The only surface species identified were zinc oxide (ZnO) and reversibly adsorbed water. Atomic force microscopy and X-ray diffraction revealed the homogeneous nucleation of ZnO grains. The kinetics of ZnO formation was followed quantitatively by in situ IR reflection-absorption spectroscopy (IRAS) integrated with a quartz crystal microbalance up to an average film thickness of 50 nm after 72 h of exposure. The quantitative results exhibit good agreement with ex situ cathodic reduction and with optical calculations of IRAS data and provide further evidence of IRAS as an in situ analytical tool with quantification capability. The ZnO growth followed the logarithmic rate law as predicted by Fehlner and Mott [Oxid. Met., 2, 59 (1970)]. © 2008 The Electrochemical Society.

  • 322.
    Randelius, Mats
    et al.
    RISE, Swerea, Swerea KIMAB.
    Krantz, Therese
    RISE, Swerea, Swerea KIMAB.
    Melander, Arne
    RISE, Swerea, Swerea KIMAB.
    Experimental testing and computer simulations of ductile fracture in tool steels2012In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 83, no 1, p. 91-99Article in journal (Refereed)
    Abstract [en]

    Ductility was determined in experimental four-point bending tests of smooth specimens of tool steel. The tool steels had different contents of carbides and carbide sizes and with a hardness of approximately 60HRc. Two of the materials tested were produced powder metallurgically, one was spray formed and one was conventionally uphill ingot cast. Carbide size distribution analysis was performed on planar polished sections of each material. Correlation between carbide microstructure and ductility performance was obtained. The fracture mechanisms were investigated with fractography. A 3D FE-model was used to simulate the four-point bending tests and thereby analyse the matrix flow curve. Also the strain at failure was analysed for each material when simulations were performed based on experimental data. SEM-images of the materials carbide microstructure were used to create 2D FE-models. The models simulated crack initiation and propagation by removing elements in the steel matrix as the plastic strain reached a critical level. With three variants, simulations of crack initiation and propagation at carbides were investigated. That was carbides with no cohesion to matrix, carbides fixed to the matrix and carbides with internal cracks. Comparison of strains at failure for the 2D and the 3D FE-models showed good correlation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 323.
    Randelius, Mats
    et al.
    RISE, Swerea, Swerea KIMAB.
    Sandström, Rolf
    RISE, Swerea, Swerea KIMAB.
    Melander, Arne
    RISE, Swerea, Swerea KIMAB.
    Fatigue strength of conventionally cast tool steels and its dependence of carbide microstructure2012In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 83, no 1, p. 83-90Article in journal (Refereed)
    Abstract [en]

    The axial fatigue strength at two million cycles was experimentally determined for two conventionally cast tool steels and successfully compared with results from a fatigue limit model. Specimens were tested both in the rolling and transverse direction and showed large differences in fatigue properties due to the segregated carbide microstructure. Rolling direction specimens experienced higher fatigue strength than the transverse direction specimens. This is due to smaller carbides present in the load affected cross section of the rolling direction fatigue test bars compared to the cross section of the transverse direction fatigue test bars. Fractographic analysis of failed specimens showed that large carbides had caused fatigue failure, which was also predicted by the model. Measured size distributions of carbides and inclusions were used as input data in the model. The probability that at least one particle will be present in the material volume having a size larger than the threshold value for crack propagation was calculated. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 324.
    Ratanathavorn, Wallop
    RISE, Swerea, Swerea KIMAB.
    Hybrid joining of aluminium to thermoplastics with friction stir welding (FSW)2012Report (Refereed)
    Abstract [en]

    Hybrid structures including aluminum-thermoplastic and aluminum-reinforced thermoplastic composite are increasingly important in the near future innovations due to its lightweight and high strength-to-weight ratio. A critical point for metal-polymer application is that sound joining of these materials is difficult to achieve owing to a large difference in surface energy and dissimilar structure between metal and polymer. In practice, two major joining methods for hybrid structures are mechanical joining and adhesive bonding. However, there are some drawbacks of these conventional methods such as stress concentration, long curing time and low reliability joints. A new novel metal-polymer hybrid joining is required to overcome these issues as well as manufacturing and cost perspectives. To this end, this work aims to develop a general methodology to apply friction stir welding techniques to join a wide range of thermoplastics with and without fibers to aluminum alloy sheets. The present work proposed an experimental study to attain insight knowledge on the influences of welding parameters on the quality of hybrid joints in term of the maximum tensile shear strength. This includes the role of tool geometries, welding methodology as well as material weldability in the investigation. The results showed that friction stir welding is a promising technique for joining of thermoplastic to aluminum. Microstructural observation showed that a good mixing between aluminum and thermoplastic as well as defect-free weldments were obtained. Tool geometries and welding speed are two factors that significantly contribute to the quality of friction stir welded hybrid joints. The results also demonstrated that weld fracture modes are associated with material mixing as well as interfacial bonding between aluminum and thermoplastic. An evaluation of the joint strength was benchmarked with the relevant literatures on hybrid joining. The results of proposed technique showed that the maximum tensile shear strength of friction stir welded joints were the same order of magnitude as the joints welded by laser welding.

  • 325.
    Ratanathavorn, Wallop
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB. KTH Royal Institute of Technology, Sweden.
    Melander, Arne
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB. KTH Royal Institute of Technology, Sweden.
    Dissimilar joining between aluminium alloy (AA 6111) and thermoplastics using friction stir welding2015In: Science and technology of welding and joining, ISSN 1362-1718, E-ISSN 1743-2936, Vol. 20, no 3, p. 222-228Article in journal (Refereed)
    Abstract [en]

    In this work, friction stir welding was used to produce shear overlap joints between aluminium and a thermoplastic (AA 6111 to polyphenylene sulphide). The process uses the friction stir welding tool to create metallic chips which merge with the molten thermoplastic to form a joint. No special surface pretreatment is required before joining. Cross-sections show mechanical locking between the chipped polymer filled zone and the surrounding aluminium sheet. The effects of joining parameters such as rotational speed, translational speed and distance to backing were investigated in relation to the joint strength and failure mode. Optimum speeds and backing distances could be identified. The joint strength is dominated by mechanical interlocking between the chip and polymer filled zone and the aluminium sheet.

  • 326.
    Ratanathavorn, Wallop
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB. KTH Royal Institute of Technology, Sweden.
    Melander, Arne
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB. KTH Royal Institute of Technology, Sweden.
    Influence of zinc on intermetallic compounds formed in friction stir welding of AA5754 aluminium alloy to galvanised ultra-high strength steel2017In: Science and technology of welding and joining, ISSN 1362-1718, E-ISSN 1743-2936, p. 1-8Article in journal (Refereed)
    Abstract [en]

    In this study, lap joints between AA5754 and DP1000 ultra-high strength steels were produced by friction stir welding. In order to investigate the roles of zinc on intermetallic phase formation and joint properties, steel substrates were used, two being galvanised coated and one uncoated. Joint performance has been evaluated in term of maximum tensile shear loading. The effects of the process parameter, translational speed; chemical compositions; and intermetallic phase formation on the mechanical properties have been investigated. The results show that joints with a galvanised layer exhibit higher strength as compared to the non-coated steel. A thicker galvanised layer promotes the presence of zinc in the aluminium matrix, resulting in better joint properties. The level of zinc contents in the aluminium matrix depends on process temperature and material circulation characteristics. Two stable Al-rich intermetallic phases, Al5Fe2 and Al13Fe4, were detected at the interface regardless of the coating conditions.

  • 327.
    Ray, R.K.
    et al.
    Tata Steel Ltd, India.
    Hutchinson, Bevis
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Ghosh, C.
    Tata Steel Ltd, India.
    'Back-annealing' of cold rolled steels through recovery and/or partial recrystallisation2011In: International Materials Reviews, ISSN 0950-6608, E-ISSN 1743-2804, Vol. 56, no 2, p. 73-97Article in journal (Refereed)
    Abstract [en]

    An evaluation of the 'back-annealing' approach for the production of high strength steel sheet is presented. This approach is different from those used in conventional current practice, e.g. for rephosphorised, microalloyed, dual phase, multiphase and transformation induced plasticity steels. The principle is to retain as much as possible of the hardening due to cold rolling while gaining ductility by controlled low temperature heat treatment (back-annealing) through recovery and/or partial recrystallisation. Unlike other processes to achieve high strength, this approach offers the possibility of cost effective high speed production in continuous annealing lines. The important role of 'back-annealing' or recovery annealing in the production of ultrafine grains in steels and in the development of higher strength ultra-thin strip cast products has also been widely recognised. In the present review, the fundamentals of the back-annealing process are discussed in terms of the constituent phenomena of recovery and recrystallisation and their kinetics. The challenges of back-annealing in steels, in terms of the production of sheets of thin gauges, are identified and possible methods to overcome these are suggested. Theoretically model approaches to the back-annealing process are also discussed. © 2011 Institute of Materials.

  • 328.
    Reuterdahl, Otto
    RISE, Swerea, Swerea KIMAB.
    Production of Fe-TiB2 composite using liquid phase sintering2013Report (Refereed)
    Abstract [sv]

    This thesis work focus on evaluating the metallurgical bonding between the TiB2 and iron grains in the Fe-TiB2 composite. The starting materials were commercial materials in form of Ferro-boron and Ferro-titanium that together with pure TiB2 powder formed a material with the composition seen below: FeB + FeTi + TiB2  52.3TiB2 + 45.7Fe + 2Ti During sintering an iron liquid phase is formed where the boron from the FeB diffuse to the titanium in FeTi which enables the formation of TiB2. The temperature used in the liquid phase sintering was chosen just above the three phase region, Fe-TiB2-liquid in the phase diagram, to get an adequate densification of the samples. However, the temperature could not be too high because of the internal stress and deformation the samples would have been exposed to. After sintering the material properties and microstructure were examined through Palmqvist indentations, Fargo and Transverse-Rupture-Strength tests and SEM studies including EBSD. Through these tests the hardness was measured to 1323 HV and the microstructure considered to be fine with well distributed phases. The EBSD also showed that the brittle Fe2B phase is present close to the TiB2 grains and that the porosity gives unreliable results for the Fargo and TRS-tests. The composite was impregnated with copper to show that it may be possible to achieve wetting of the TiB2 phase by casting and to perform new tests on the material with less porosity

  • 329.
    Reuterswärd, Patrik
    RISE, Swerea, Swerea KIMAB.
    Guide för Korrosivitetsklass för stålkonstruktioner2012Report (Refereed)
    Abstract [sv]

    Korrosivitetskategorierna C1-C5 och CX enligt ISO 9223:2012 definieras som en atmosfärsmiljö där en fri exponerad metallpanel under ett år har korrosionsförluster inom ett visst intervall. En viktig användning av Korrosivitetskategorier är stöd för beställare. Genom att ange en Korrosivitetskategori samt en specificerad livslängd, underlättas konstruktionsarbetet och dimensioneringen av nödvändigt korrosionsskydd. Den framtida korrosionen för kolstål och zink kan i vissa fall uppskattas om områdets korrosivitet eller områdets korrosivitetskategori (C1-C5, CX) är känd. Däremot finns det inom kategorierna Im1-Im3 för exponering i vatten eller jord ingen direkt korrelation mellan kategori och framtida korrosion. Funktionskrav för konstruktioner som enbart bygger på korrosivitetskategori för förväntad användningsmiljö, konstruktionens specificerade tekniska livslängd och korrosionsskyddets förväntade beständighet enligt SS-EN ISO 12944, ger stor frihet för en konstruktör eller en entreprenör. Med den nya standarden SS-EN 1090-2, måste man dock för varje enskild ny stålkonstruktion ha en förteckning med krav på konstruktion och utförande. För att framgångsrikt utforma en konstruktion med lång teknisk livslängd och där de funktionella kraven förväntas bibehållas under livslängden, utan reparationer eller omfattande underhåll, är det nödvändigt att de allmänna funktionskraven kompletteras med en rad ytterligare krav och riktlinjer för korrosionsskydd.I internationella standarder finns mycket få krav och anvisningar om hur konstruktionsutförande och korrosionsskydd ska anpassas för olika korrosivitetskategorier. Korrosionsskydd av stålkonstruktioner genom målning är ett undantag. Ett material, en vald konstruktionslösning, eller en komponent kan inte generellt anses uppfylla kraven för en Korrosivitetsklass, utan att man dessutom anger teknisk livslängd och tar hänsyn till den faktiska utformningen och förhållanden under användning.

  • 330.
    Reuterswärd, Patrik
    RISE, Swerea, Swerea KIMAB.
    Slutrapport Ommålning av blymönjemålade objekt: Repainting of red lead painted objects2014Report (Refereed)
    Abstract [sv]

    Blymönjemålning som användes under 1900-talet för rostskydd var i många fall mycket beständig. Därför finns fortfarande kvar många stålkonstruktioner med blymönjemålning. Hur man formulerade blymönja och täckfärger på trettiotalet finns dokumenterat i IVA:s korrosionsnämnds Medelande nr 1 (1935). Det finns blymönjemålade objekt från trettiotalet som enbart är ommålade en gång under sjuttiotalet och som fortfarande har en målning i utmärkt skick. Många av de gamla stålkonstruktionerna används och är fortfarande mycket viktiga för vår infrastruktur. Gamla stålkonstruktioner uppfyller oftast inte de moderna krav som man idag ställer för att korrosionsskyddas genom rostskyddsmålning. Därför är det inte lämpligt att betrakta äldre stålkonstruktioner som om de vore nya. Man ska skilja mellan nymålning av moderna konstruktioner och underhåll av äldre stålkonstruktioner. Vid ommålning av äldre konstruktioner är det inte självklart att man ska blästra bort all färg och använda moderna färgtyper för en komplett nymålning. Uppföljning av tre entreprenader har visat att äldre stålkonstruktioner kan ommålas med klassiska oljealkyder till en betydligt lägre kostnad än om man hade blästrat bort all gammal färg och utfört en komplett nymålning. För äldre blymönjemålade ytor i gott skick bör man i första hand använda ett färgsystem med Isotrol Grund och ett skikt rostskyddspigmenterad alkydoljetäckfärg, om möjligt aluminiumfärgad med samma pigmentering som rekommenderades 1935. Repainting of red lead painted objects The lead based paints used during the 20th century for anti-corrosion were generally very durable. Therefore, lead based paints still remains on many old steel constructions. Methods to formulate lead primers and topcoats have been documented in the first technical report “Meddelande no 1” (1935) ref [1] from the corrosion committee of Ingenjörsvetenskaps­akademin (IVA) in Sweden. There are painted steel constructions from the thirties that have only been maintained once and still have paints in excellent condition. Many of these old steel constructions are still in service and are vital parts of the infrastructure in Sweden. Older steel constructions do not fulfil the modern requirements of corrosion protection by painting. It is not appropriate to manage older steel constructions as if they were new. One should distinguish between repainting of modern constructions and maintenance of older steel constructions. When repainting older constructions, it is not certain that all old paints must be removed and repainted by modern paint types. Follow-up of three refurbishments have shown that older steel structures can be repainted by classic oil modified alkyd pains at a significantly lower cost than if all the old paints had been removed by sand blasting. Recommended maintenance of older steel constructions with lead based paints in good condition is; removal of loosely adhering paints, priming with Isotrol Primer and one layer anticorrosive oil modified alkyd topcoat, if possible aluminium coloured with the same formulation that was recommended in 1935.

  • 331.
    Rosales, B.M.
    et al.
    CIDEPINT.
    Vera, R.
    Pontificia Universidad Católica de Valparaíso.
    De Rincon, O.T.
    Universidad Del Zulia.
    Di Sarli, A.
    CIDEPINT.
    Rocha Valenzuela, J.A.
    University of San Andres.
    Tidblad, Johan
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Atmospheric corrosion2012In: International Journal of Corrosion, ISSN 1687-9325, E-ISSN 1687-9333, Vol. 2012Article in journal (Refereed)
    Abstract [en]

    [No abstract available]

  • 332.
    Ruel, F.
    et al.
    Aperam R and D, France.
    Saedlou, S.
    Aperam R and D, France.
    Mendibide, Christophe
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Influence of temperature and pH on SCC assisted by H 2 S susceptibility of 22 %Cr duplex2018In: NACE - International Corrosion Conference SeriesVolume 2018-April, 2018Corrosion Conference and Expo 2018; Phoenix; United States;, National Assoc. of Corrosion Engineers International , 2018Conference paper (Refereed)
    Abstract [en]

    Depending on environmental conditions UNS (1) S32205 duplex stainless steel may suffer from Stress Corrosion Cracking (SCC) assisted by H 2 S initiated by local corrosion processes that involve the selective dissolution of the ferritic phase or the austenitic phase. The intent of this paper is first to study the evolution of the susceptibility of SCC assisted by H 2 S according temperature and pH. In a second phase, links are highlighted between the differences of cracking resistance and localized corrosion morphologies. Results show that the temperature of highest susceptibility to SCC assisted by H 2 S depends on the pH of the environment, moving from 80 °C at low pH (2.8 - 3.5) to temperature between 50 - 20 °C at higher pH (4.5 - 6.0). The maximum of cracking susceptibility seems to correlate with selective corrosion of ferrite coupled with transgranular cracks of the austenite.

  • 333.
    Ruel, F.
    et al.
    Aperam RandD, France.
    Saedlou, S.
    Aperam RandD, France.
    Mendibide, Christophe
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Manchet, S. L.
    Industeel, France.
    Wolski, K.
    Ecole Nationale Supérieure des Mines de Saint-Etienne, France.
    Effect of the substitution of Ni by N and Mn in Lean Duplex Stainless steels on Stress corrosion Cracking assisted by H 2 S2017In: NACE - Int. Corros. Conf. Ser., National Assoc. of Corrosion Engineers International , 2017, p. 3376-3387Conference paper (Refereed)
    Abstract [en]

    The importance of passive film stability and mechanical properties of the UNS (1) S32304, S32202 and S32101 Lean Duplex Stainless Steel grades on Stress Corrosion Cracking (SCC) is discussed in this paper. Measurement of uniform corrosion resistance in the presence of H 2 S, through polarization curves, and slip steps height and spacing, through Atomic Force Microscopy technique (AFM) have been performed. Results show that, as opposed to N, Mn decreases the passive film stability and slip steps height and spacing at the surface of the austenitic phase. Therefore, on the basis of slow strain rate tensile tests where the grade S32202 show a greater SCC resistance than the grades S32304 and S32101, it can be concluded that the electrochemical passive film stability makes the larger contribution to SCC phenomenon and so the negative impact of Mn.

  • 334.
    Rögener, F.
    et al.
    VDEh-Betriebsforschungsinstitut GmbH.
    Sartor, M.
    VDEh-Betriebsforschungsinstitut GmbH.
    Reichardt, T.
    VDEh-Betriebsforschungsinstitut GmbH.
    Bergsjö, Petter
    RISE, Swerea, Swerea KIMAB.
    Römhild, Stefanie
    RISE, Swerea, Swerea KIMAB.
    Polymer corrosion in steel pickling lines - Reasons and approaches [Kunststoffkorrosion in Beizlinien der stahlindustrie - Ursachen und Lösungsansätze]2013In: Stahl und Eisen (1881), ISSN 0340-4803, Vol. 133, no 1, p. 65-70Article in journal (Refereed)
    Abstract [de]

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

  • 335.
    Rögener, Frank
    et al.
    VDEh-Betriebsforschungsinstitut GmbH, Germany.
    Sartor, Miriam
    VDEh-Betriebsforschungsinstitut GmbH, Germany.
    Reichardt, Tilo
    VDEh-Betriebsforschungsinstitut GmbH, Germany.
    Bergsjö, Petter
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Resistance of plastics in plants of surface technology [Beständigkeit von Kunststoffen in Anlagen der Oberflächentechnik]2015In: Galvanotechnik, ISSN 0016-4232, Vol. 106, no 7, p. 1370-1377Article in journal (Refereed)
    Abstract [en]

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

  • 336.
    Römhild, Stefanie
    et al.
    RISE, Swerea, Swerea KIMAB.
    Bergman, Gunnar
    RISE, Swerea, Swerea KIMAB.
    Hedenqvist, M.S.
    Royal Institute of Technology.
    Short-term and long-term performance of thermosets exposed to water at elevated temperatures2010In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 116, no 2, p. 1057-1067Article in journal (Refereed)
    Abstract [en]

    The water-transport, mechanical, and chemical- structure changes in various vinyl ester, novolac, and urethane-modified vinyl ester thermosets exposed to water at 50 to 95°C for times up to 1000 days have been studied within the framework of a larger study of osmotic blistering in fiber reinforced plastics (FRP) process components. The water sorption saturation concentration did not reach a steady-state value but gradually increased in many cases upon long-term exposure. The diffusion coefficient was not significantly affected. Infrared spectroscopy and gas chromatography- mass spectrometry indicated that the net mass loss from the thermosets on immersion in water was due to the leaching of non-reacted styrene, monomer, and additives. It is suggested that this, together with polymer relaxation processes (as measured on specimens under tension in water at 80°C), is the primary reason for the time-dependent increase in the water saturation concentration. Infrared spectroscopy indicated that, even at the highest temperatures, hydrolysis of the polymer ester groups was small. Correlations were found between the styrene content in the uncured thermosets, the estimated solubility parameters, and the sorption and diffusion coefficients. © 2009 Wiley Periodicals, Inc.

  • 337.
    Römhild, Stefanie
    et al.
    RISE, Swerea, Swerea KIMAB.
    Hedenqvist, M.S.
    Royal Institute of Technology.
    Bergman, Gunnar
    RISE, Swerea, Swerea KIMAB.
    The effect of water activity on the sorption and diffusion of water in thermosets based on polyester, vinyl ester, and novolac resins2012In: Polymer Engineering and Science, ISSN 0032-3888, E-ISSN 1548-2634, Vol. 52, no 4, p. 718-724Article in journal (Refereed)
    Abstract [en]

    In this work, the transport properties of water in various thermoset resins typically used for fiber-reinforced plastic process equipment (vinyl ester, novolac, bisphenol-A-epoxy-based polyester, and urethane-modified vinyl ester) were systematically studied with a focus on the effects of water activity. Sorption and desorption studies were carried out in aqueous solutions (water activity = 0.78-1) with different salts (NaCl, MgCl 2, Na 2SO 4, and KCl) and one nonionic substance (sucrose) within the temperature interval 65-95°C. It was found that the water concentration in thermoset resins with different chemical structures could be predicted from the water activity, regardless of the actual solute (salt or sucrose) in the aqueous solution. The water quasi-equilibrium concentration decreased with decreasing water activity, whereas the average diffusion coefficient was considered to be independent of water activity in the studied water activity range. A relationship, based on a power law fit, was established describing the water concentration as a function of the water activity and the concentration of pure water. The relationship was independent of resin chemistry and temperature. © 2012 Society of Plastics Engineers.

  • 338.
    Safi-Naqvi, S.H.
    et al.
    University of Birmimgham.
    Hutchinson, Bevis
    RISE, Swerea, Swerea KIMAB.
    Barnett, M.R.
    Deakin University.
    Texture and mechanical anisotropy in three extruded magnesium alloys2008In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 24, no 10, p. 1283-1292Article in journal (Refereed)
    Abstract [en]

    One ZM61 alloy (6·2%Zn, 1·2%Mn) and two magnesium alloys containing nominally 3% of neodymium and yttrium respectively have been prepared in the form of hot extruded flat strips. Their textures and microstructures have been quantified and series of mechanical tests were carried out to determine plane stress yield loci in both the solution treated and aged conditions. The ZM61 alloy had a sharp texture and marked anisotropy of strength that could be rationalised in terms of deformation by basal 〈a〉 slip and {101̄2}〈1011〉 twinning. This material was much weaker in compression than in tension. Precipitation hardening on aging caused a greater impedance to twinning than to slip with the result that the anisotropy was somewhat reduced. The Mg-3Nd alloy had a very weak and different texture but nevertheless demonstrated a pronounced anisotropy of strength. Aging increased the yield stress by about 80% and also inhibited twinning to some extent although the degree of anisotropy remained almost unaffected. The Mg-3Y alloy which showed a texture of intermediate strength was different in type from either of the others. Its strength behaviour was close to isotropic; in particular, no difference existed between tensile and compressive loading, and aging produced only a marginal increase in strength. Twins were relatively infrequent in the deformed Mg-3Y alloy but its mechanical behaviour could not be rationalised according to simple models. © 2008 Institute of Materials, Minerals and Mining.

  • 339.
    Salvatori, I.
    et al.
    RINA, Italy.
    Alleva, L.
    RINA, Italy.
    Duret-Thual, Claude
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Thierry, Dominique
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Trillo, E.
    SWRI, US.
    Martin, J. W.
    JWM Materials Consulting Ltd, UK.
    Assessment of the hydrogen induced stress cracking resistance of precipitation hardened nickel-based alloys using the slow strain rate tensile test method: Influence of microstructure2019In: NACE - International Corrosion Conference SeriesVolume 2019-March, 2019, Article number 13365Corrosion Conference and Expo 2019; Nashville; United States; 24 March 2019 through 28 March 2019, National Assoc. of Corrosion Engineers International , 2019Conference paper (Refereed)
    Abstract [en]

    Within the framework of a Joint Industrial Project sponsored by several petroleum companies, the behavior of several Precipitation Hardened (PH) Ni-based alloys with respect to Hydrogen Induced Stress Cracking (HISC) resistance was studied, using the Slow Strain Rate Tensile (SSRT) test method conducted under hydrogen charging conditions (applying a constant cathodic current density throughout the test). Among the test materials, several industrial Heats of UNS N07718, UNS N09945/945X, UNS N09925, UNS N09935, UNS N07725 and UNS N07716 were evaluated. A detailed microstructural analysis was performed on each heat, at different levels, involving SEM and TEM examinations at high magnification on etched samples, to reveal the phases present at grain boundaries. Methodologies were developed to quantify the grain boundary coverage (length of precipitates at grain boundary divided by the total grain boundary length), and to study the distribution in size (equivalent diameter, surface, shape factor) of the grain boundary precipitates, and applied to the studied materials. Elemental chemical analysis of the precipitates was also conducted by Energy Dispersive X-ray spectrometry. The performance of the different alloys with respect to HISC resistance is discussed on the basis of the plastic elongation obtained in the SSRT tests under cathodic polarization, the microstructural features and the microstructural criteria given in the API 6A CRA standard. 

  • 340.
    Sandberg, Bertil
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Lindell, B.
    3CCC, Sweden.
    Stray current corrosion detection: The use of penetration probes2017In: Corrosion and Prevention 2017, Australasian Corrosion Association , 2017Conference paper (Refereed)
    Abstract [en]

    Pipelines are protected against corrosion by a combination of a high quality coating and cathodic protection systems. They are in many cases exposed to interference from dc and/or ac currents. If the current is transferred to the pipeline in a conductive way it can be an advantage not to have a coating with very high resistance. This enables mitigations as local groundbeds or introducing a voltage drop in the pipe. To detect ac corrosion the local corrosion rate must be monitored. The local corrosion rate can be evaluated by excavating test coupons but penetration probes give an economic benefit and results are received without delay, giving the most cost effective way to monitor a highly influenced section of the pipe network.

  • 341.
    Sandström, Rolf
    et al.
    RISE, Swerea, Swerea KIMAB.
    Hallgren, Josefin
    RISE, Swerea, Swerea KIMAB.
    The role of creep in stress strain curves for copper2012In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 422, p. 51-Article in journal (Refereed)
    Abstract [en]

    A model for plastic deformation in pure copper taking work hardening, dynamic recovery and static recovery into account, has been formulated using basic dislocation mechanisms. The model is intended to be used in finite-element computations of the long term behaviour of structures in Cu-OFP for storage of nuclear waste. The relation between the strain rate and the maximum flow stress in the model has been demonstrated to correspond to strain rate versus stress in creep tests for oxygen free copper alloyed with phosphorus Cu-OFP. A further development of the model can also represent the primary and secondary stage of creep curves. The model is compared to stress strain curves in compression and tension for Cu-OFP. The compression tests were performed at room temperature for strain rates between 5 × 10 -5 and 5 × 10 -3 s -1. The tests in tension covered the temperature range 20-175°C for strain rates between 1 × 10 -7 and 1 × 10 -4 s -1. Consequently, it is demonstrated that the model can represent mechanical test data that have been generated both at constant load and at constant strain rate without the use of any fitting parameters. © 2011 Elsevier B.V. All rights reserved.

  • 342.
    Sandström, Rolf
    et al.
    RISE, Swerea, Swerea KIMAB.
    Wu, Rui
    RISE, Swerea, Swerea KIMAB.
    Influence of phosphorus on the creep ductility of copper2013In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 441, p. 364-371Article in journal (Refereed)
    Abstract [en]

    Around 1990 it was discovered that pure copper could have extra low creep ductility in the temperature interval 180-250 C. The material was intended for use in canisters for nuclear waste disposal. Although extra low creep ductility was not observed much below 180 C and the temperature in the canister will never exceed 100 C, it was feared that the creep ductility could reach low values at lower temperatures after long term exposure. If 50 ppm phosphorus was added to the copper the low creep ductility disappeared. A creep cavitation model is presented that can quantitatively describe the cavitation behaviour in uniaxial and multiaxial creep tests as well as the observed creep ductility for copper with and without phosphorus. A so-called double ledge model has been introduced that demonstrates why the nucleation rate of creep cavities is often proportional to the creep rate. The phosphorus agglomerates at the grain boundaries and limits their local deformation and thereby reduces the formation and growth of cavities. This explains why extra low creep ductility does not occur in phosphorus alloyed copper. © 2013 Published by Elsevier B.V.

  • 343.
    Sandström, Rolf
    et al.
    RISE, Swerea, Swerea KIMAB.
    östling, Henrik
    RISE, Swerea, Swerea KIMAB.
    Modelling of creep in friction stir welded copper2013Conference paper (Refereed)
    Abstract [en]

    Copper canisters for storage of nuclear waste will be exposed to creep. The canisters will be closed with friction stir welding (FSW). To describe the creep behaviour of the welds, uniaxial creep tests have been performed. A previously developed fundamental creep model for parent metal is applied to the different weld zones. The differences in microstructure and yield strength between the weld zones are taken into account. Creep strain versus time curves for the weld zones have successfully been predicted without the use of any adjustable parameters. It should be noted that the temperature range of interest of 50-100°C is deep down in the power law break down regime with Norton exponents between 25 and 100. The constitutive equations are used in FEM computations of creep in the canister weldments. © W. S. Maney & Son Ltd. 2013.

  • 344.
    Sandström, Rolf
    et al.
    RISE, Swerea, Swerea KIMAB.
    Östling, Henrik
    RISE, Swerea, Swerea KIMAB.
    Jin, L.-Z.
    Royal Institute of Technology (KTH).
    Modelling of creep in friction stir welded copper2013In: Energy Materials: Materials Engineering and Engineering for Energy Systems, ISSN 17489237, Vol. 8, no 3, p. 350-354Article in journal (Refereed)
    Abstract [en]

    Copper canisters for storage of nuclear waste will be exposed to creep. The canisters will be closed with friction stir welding (FSW). To describe the creep behaviour of the welds, uniaxial creep tests have been performed. A previously developed fundamental creep model for parent metal is applied to the different weld zones. The differences in microstructure and yield strength between the weld zones are taken into account. Creep strain versus time curves for the weld zones have successfully been predicted without the use of any adjustable parameters. It should be noted that the temperature range of interest of 50–100°C is deep down in the power law break down regime with Norton exponents between 25 and 100. The constitutive equations are used in FEM computations of creep in the canister weldments. © W. S. Maney & Son Ltd. 2013.

  • 345.
    Sathirachinda, N.
    et al.
    Royal Institute of Technology.
    Gubner, Rolf
    RISE, Swerea, Swerea KIMAB.
    Pan, J.
    Royal Institute of Technology.
    Kivisäkk, U.
    Sandvik Materials Technology.
    Characterization of phases in duplex stainless steel by magnetic force microscopy/scanning Kelvin probe force microscopy2008In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 11, no 7, p. C41-C45Article in journal (Refereed)
    Abstract [en]

    A 2205 duplex stainless steel, which had undergone a slow cooling process in order to precipitate intermetallic phases, was characterized by means of magnetic force microscopy (MFM) and scanning Kelvin probe force microscopy (SKPFM), in addition to conventional scanning electron microscope and energy-dispersive spectroscopy analysis. MFM measurements yield information about the magnetic domain distribution, while SKPFM provides the variation in Volta potential between austenite (γ), ferrite (α), and sigma phases (). In general, paramagnetic austenite exhibits the highest Volta potential, followed by nonmagnetic sigma phase and ferromagnetic ferrite, respectively. Results show the applicability of MFM/SKPFM techniques for characterization of the individual phase properties of duplex stainless steel. Because a cross talk between magnetic and Volta potential signals has been observed, it is recommended to perform SKPFM measurements with nonmagnetic tips. © 2008 The Electrochemical Society.

  • 346.
    Sathirachinda, N.
    et al.
    Royal Institute of Technology.
    Pettersson, R.
    Outokumpu Stainless AB.
    Wessman, Sten
    RISE, Swerea, Swerea KIMAB.
    Pan, J.
    Royal Institute of Technology.
    Study of nobility of chromium nitrides in isothermally aged duplex stainless steels by using SKPFM and SEM/EDS2010In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 52, no 1, p. 179-186Article in journal (Refereed)
    Abstract [en]

    The relative nobility of Cr2N in duplex stainless steels (DSSs) was investigated in isothermally aged 2205 and 2507 DSSs using scanning Kelvin probe force microscopy (SKPFM) and SEM/EDS. The specimens contained nitrides, austenite and sigma phase but no ferrite. In these materials, Cr2N exhibits a higher Volta potential than sigma phase and austenite, implying the highest practical nobility of Cr2N compare to the surrounding phases. The composition and alloying effect can explain the relative nobility of the phases. The apparent "size effect" of small Cr2N on the measured Volta potential difference is probably due to the influence of surrounding matrix. © 2009 Elsevier Ltd. All rights reserved.

  • 347.
    Sathirachinda, N.
    et al.
    Royal Institute of Technology.
    Wessman, Sten
    RISE, Swerea, Swerea KIMAB.
    Pettersson, R.
    Outokumpu Stainless AB.
    Evaluation of corrosion behaviour in a 317L stainless steel strip welding using scanning Kelvin probe force microscopy2011In: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 62, no 12, p. 1092-1099Article in journal (Refereed)
    Abstract [en]

    Scanning Kelvin probe force microscopy and magnetic force microscopy have been used in combination with SEM/EDS and immersion tests to study a 317L electroslag strip weld which contains austenite and interdendritic ferrite and sigma phase. The individual phases can easily be recognized from the compositional contrast, magnetic pattern and Volta potential variation. Austenite, which is paramagnetic, exhibits the highest Volta potential followed by non-magnetic sigma phase and ferromagnetic ferrite, respectively. Corrosion testing in acidic chloride solutions indicates that the Volta potential measured in air can be related to the tendency to uniform corrosion, while pitting corrosion shows different dependence. In both cases ferrite and sigma phase behaved in a similar manner, indicating that there was no specific detrimental effect of sigma phase on corrosion properties in this material. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 348.
    Sederholm, Bror
    RISE, Swerea, Swerea KIMAB.
    Cathodic protection of concrete structures with thermally sprayed sacrificial zinc anodes - Critical parameters for the protective ability of the sprayed-on anode2012In: Concrete Repair, Rehabilitation and Retrofitting III - Proceedings of the 3rd International Conference on Concrete Repair, Rehabilitation and Retrofitting, ICCRRR 2012, 2012, p. 978-984Conference paper (Refereed)
    Abstract [en]

    This paper presents an ongoing project regarding Cathodic protection of concrete structures with thermally sprayed sacrificial zinc anodes. The project is divided into two parts: Stage 1 shows the results from a survey of literature and practical experiences of the use of cathodic protection of concrete structures with sprayed zinc sacrificial anodes. Results from investigations of thermally zinc sprayed concrete structures such as concrete walls in the water intake building on a nuclear plant and on the edge beam of the Öland Bridge are presented in the paper. Stage 2 in the project is focused on the critical parameters for the protective ability of the sprayed-on anode. A laboratory setup and a field object are presented as well as the methods used to evaluate the sprayed-on anode. The present investigations show that the resistivity of the concrete has a great influence on the protective ability of the sprayed-on anode. Further, the life length of the zinc anode depends on the external environmental conditions at the anode. In conclusion it can be stated that the prospect of using cathodic protection with thermally sprayed zinc sacrificial anodes is promising but in order to optimize the use, threshold values need to be determined regarding for example the humidity, carbonation depth and the chloride content of the concrete. © 2012 Taylor & Francis Group.

  • 349.
    Sederholm, Bror
    RISE, Swerea, Swerea KIMAB.
    Varmförzinkade räckesståndare med och utan undergjutning av fotplatta: korrosionsrisker vid kontakt med rostfria skruvar2012Report (Refereed)
    Abstract [sv]

    ”Varmförzinkade räckesståndare med fotplatta i kontakt med rostfria skruvar”. Projektet avslutas med denna rapport i december 2012. I föreliggande slutrapport redovisas resultat från okulära undersökningar vid 19 vägbroar av korrosionstillståndet hos varmförzinkade räckesståndare med fotplatta, med och utan undergjutningsbruk, fastskruvade på fastgjutna utstickande rostfria skruvar. Av totalt 19 undersökta vägbroar är det en vägbro som korsar över en elektrifierad järnväg. Denna vägbro togs i trafik under 2010. De övriga undersökta vägbroarna är minst tre år gamla. I rapporten ingår även resultat från en kontrollerad utomhusexponering som genomförts vid Trafikverkets/SP:s provningsstation vid riksväg 40 i Borås. Vid den kontrollerade utomhusexponeringen har den galvaniska inverkan från rostfria fästelement på provplåtar av varmförzinkat stål och zink undersökts. Även inverkan av främmande järnpartiklar på rostfria provplåtars korrosionsegenskaper har ingått i undersökningarna. I denna rapport redovisas också resultat av smörjegenskaperna hos olika provade smörjmedel som används vid fastskruvning av varmförzinkade räckesståndare med fotplatta med rostfria muttrar och skruvar. Denna undersökning har gjorts på en nybyggd (2011) motorvägsbro utefter E20 vid Alingsås. Vid fastskruvning av broräckena användes en digital momentnyckel. Åtdragningsmomentet som användes för varje enskild rostfri mutter var i samtliga fall 235 Nm. Från resultaten av de olika undersökningarna kan följande slutsatser och rekommendationer ges: Okulär undersökning av fotplattornas korrosionstillstånd hos vägbroar äldre än tre år - Vid undersökning av korrosionstillståndet hos varmförzinkade räckesståndare med fotplatta, med och utan undergjutning, fastsatta med utstickande och fastgjutna rostfria skruvar konstaterades korrosionsangrepp (vitrost) på fotplattans ovansida under de rostfria brickorna. - Vid kontaktpunkterna mellan rostfri skruv och i sidan i fotplattans genomgående hål har konstaterats både vitrost och rödrost . Korrosionsangreppen i väggen i fotplattans håligheter är mer omfattande om undergjutningsbruk används i stället för att inte använda undergjutningsbruk. - Varmförzinkade fotplattor som är målade har få/eller inga korrosionsangrepp på fotplattans ovansida under rostfria brickor och i kontaktpunkterna mellan rostfri skruv och i sidan i fotplattans genomgående hål. - För vägbron, vid Fivelstavägen utanför Motala, som korsar över en elektrifierad järnväg har inga korrosionsskador konstaterats (hösten 2012) på brons varmförzinkade fotplattor som är rostskyddsmålade och utan undergjutningsbruk. Vägbron togs i trafik i våren 2010. - Det rekommenderas att de varmförzinkade räckesståndarnas fotplattor målas för att hindra galvanisk korrosion på fotplattans ovansida under rostfri bricka och i kontaktytan mellan rostfri skruv och i fotplattans vägg i hålighet. Fältundersökning av rostfria fästelements galvaniska inverkan på varmförzinkat kolstål och zink - Den galvaniska inverkan från rostfria fästelement är betydligt lägre på provplåtar av varmförzinkat kolstål än på provplåtar av zink. - Den uppmätta korrosionshastigheten hos tre provplåtar av varmförzinkat kolstål ihopkopplat med rostfria fästelement är ca 4,0 μm/år (medelvärde av tre provplåtar) och för provplåtar av zink ihopkopplat med rostfria fästelement är den uppmätta medelkorrosionshastigheten ca 5,9 μm/år (medelvärde av tre provplåtar) efter två års utomhusexponering vid riksväg 40 i Borås. - Det maximala gropfrätningsdjupet hos provplåtar av varmförzinkat kolstål (medelvärde från tre provplåtar som varit ihopkopplade med rostfria fästelement) uppmättes till ca 40 μm och för provplåtar av zink uppmättes ett maximalt gropfrätningsdjup till ca 137 μm (medelvärde från tre provplåtar ihopkopplade med rostfria fästelement). Fältundersökning av åtdragningsmoment hos rostfria skruvförband - Vid ett ådragningsmoment av 235 Nm vid fastskruvning med olika smörjmedel av varmförzinkade räckesståndare med fotplatta med rostfria muttrar och skruvar har ingen skärning mellan rostfri mutter och skruv uppstått . - Ett år efter att samtliga undersökta rostfria muttrar dragits till ett åtdragningsmoment av 235 Nm konstaterades att åtdragningsmomentet i samtliga fall hade sjunkit kraftigt. I vissa fall hade åtdragningsmoment sjunkit till 0 Nm, dvs förspänningskraften är helt eliminerad. - Vid för ett lågt åtdragningsmoment kan fukt tränga in mellan rostfri bricka och fotplatta vilket kan innebära en ökad risk för spalt- och galvanisk korrosion på varmförzinkad fotplatta. - Vid användning av rostfria muttrar till utstickande skruvar för fastsättning av varmförzinkade räckesståndare med fotplatta rekommenderas att det görs en efterdragning av muttrarna till föreskrivet åtdragningsmoment eller att låsningsbara muttrar används istället för ”vanliga” muttrar. Fältundersökning av inverkan av främmande järnpartiklar på rostfria provplåtar - Ingen negativ inverkan av främmande järnpartiklar på de rostfria provplåtarnas korrosionsegenskaper har kunnat konstateras efter två års utomhusprovning vid riksväg 40 i Borås.

  • 350.
    Sederholm, Bror
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Ahlström, Johan
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Rostfria ståls korrosionshärdighet och galvaniska inverkan på kolstål i betong med hög fukt- och kloridhalt2013Report (Refereed)
    Abstract [sv]

    Föreliggande rapport avslutar FoU-projektet - Rostfria ståls korrosionsegenskaper i betong med en hög fukt- och kloridhalt. I rapporten ingår resultat från fyra delrapporter som tidigare publicerats inom projektet. I rapporten ingår även nya resultat från två års utomhusexponering i havsvatten och i stadsatmosfär av betongingjutna provstänger av rostfritt stål (kamstänger) av stålkvaliteten EN 1.4301, 1.4436, 1.4162, 1.4362 och 1.4462 samt provstänger av kolstål ihopkopplade med rostfria provstänger för att undersöka risken för galvanisk korrosion på kolstålet. Betongblock av tre olika betongkvaliteter (OPC C45/55, CEM I, PFA C32/40, CEM IIB-V och GGBFS C32/40, CEM IIIA) ingår i undersökningarna. Vid utomhusexponering i stadsatmosfär innehåller betongblocken före exponering 2-10 mass-% klorider per bindemedelsvikt och har ett täckande betongskikt av 15 mm och ett vbt av 0,45. Vid utomhusexponering i havsvatten innehåller samtliga betongblock före exponering en total kloridhalt av 3 % klorider per bindemedelsvikt och ett täckande betongskikt av 15 mm och vbt 0,45. Samtliga utförda undersökningarna (utomhus och på laboratorium) visar att rostfri stålarmering av stålkvaliteten EN 1.4301, 1.4436, 1.4162, 1.4362 och 1.4462 har betydligt bättre förmåga att motstå korrosionsangrepp i en kloridhaltig betong jämfört med ett vanligt kolstål. Förmågan hos rostfri armering att motstå korrosionsangrepp i en kloridhaltig betong beror framförallt av halten legeringsämnen som finns i det rostfria stålet. De legeringsämnen som har stor betydelse för det rostfria stålets förmåga att motstå korrosionsangrepp är framförallt krom, nickel, molybden och kväve. Det framgår vidare att korrosionshärdigheten hos fem olika rostfria stålkvaliteter som ingått i laboratorieundersökningarna ökar enligt följande ordning: (sämst) EN 1.4301 < EN 1.4162 < EN 1.4436 < EN 1.4362 < EN 1.4462 (bäst). Vid en total kloridhalt av 3 % per bindemedelvikt i betongblock med olika bindemedel (OPC C45/55, CEM I, PFA C32/40, CEM IIB-V och GGBFS C32/40, CEM IIIA) som exponerats delvis nedsänkta i havsvatten i två år kunde inga för ögat synliga, korrosionsangrepp konstateras på rostfria provstänger av stålkvaliteten EN 1.4301, 1.4436, 1.4162, 1.4362 och 1.4462.

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v. 2.35.8