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  • 1.
    Engberg, Göran
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Grehk, Mikael
    Sandvik Materials Technology.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Analysis of the plastic deformation behavior for two austenitic NiCr-steels with different stacking fault energies2018In: International Journal of Computational Physics Series, ISSN 2631-8350, Vol. 1, no 1, p. 137-141Article in journal (Refereed)
    Abstract [en]

    Two austenitic stainless steels, with low and medium stacking fault energies (SFE), 20 mJ/m2 and 30 mJ/m2 respectively, have been studied by conventional tensile tests and in situ tensile tests in a FEG-SEM equipped for EBSD. High angle boundaries (HAB) and low angle boundaries (LAB) with misorientations >= 10o and >= 2o respectively have been determined, and size distributions for the LABs have been derived by linear intercepts. It was found that the size distributions could be described by bimodal lognormal functions. For the steel with highest SFE plastic deformation took place by dislocation slip only while the steel with low SFE deformed by slip and twinning. Using a model for slip based on the evolution of the dislocation density with the generation of dislocations inversely proportional to the mean free distance of slip and recovery of dislocations proportional to the dislocation density the stress strain-curves were analyzed and the results compared with the measured quantities. The mean free distance of slip as evaluated from the stress-strain curve for the steel with the highest SFE correlates very well with the mean size of the LABs intercept. The rate of recovery also gave an expected stress dependence. The stress needed to start deformation twinning was based on the assumption that Shockley partials become completely separated in the slip plane. The thus calculated values for the twinning stress showed an excellent agreement with the observed start of twinning as given by EBSD evaluation of twin boundaries (TB). For the alloy with low SFE both surface grains (in situ test) and bulk grains (from interrupted conventional tests) were studied. The stress needed for slip and twinning of surface grains was, as expected, in the order of 0.5-0.6 times the applied stress.

  • 2.
    Engberg, Göran
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Kero, Ida
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Modeling microstructure development during hot working of an austenitic stainless steel2013In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 753, p. 423-426Article in journal (Refereed)
    Abstract [en]

    A number of physically based models are combined in order to predict microstructure development during hot deformation. The models treat average values for the generation and recovery of vacancies and dislocations, recrystallization and grain growth and the dissolution and precipitation of second phase particles. The models are applied to a number of laboratory experiments made on 304 austenitic stainless steel and the model parameters are adjusted from those used for low alloyed steel mainly in order to obtain the right kinetics for the influence of solute drag on climb of dislocations and on grain growth. The thermodynamic data are obtained using Thermo-Calc© to create solubility products for the possible secondary phases. One case of wire rolling has been analyzed mainly concerning the evolution of recrystallization and grain size. The time, temperature and strain history has been derived using process information. The models are shown to give a fair description of the microstructure development during hot working of the studied austenitic stainless steel. © (2013) Trans Tech Publications, Switzerland.

  • 3. Heinrichs, J.
    et al.
    Norgren, S.
    Jacobson, S.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Influence of cemented carbide binder type on wear initiation in rock drilling – Investigated in sliding wear against magnetite rock2019In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 85, article id 105035Article in journal (Refereed)
  • 4. Heinrichs, J.
    et al.
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Materials Technology. Uppsala University.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Jacobson, S.
    On the deformation mechanisms of cemented carbide in rock drilling: Fundamental studies involving sliding contact against a rock crystal tip2018In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 77, p. 141-151Article in journal (Refereed)
    Abstract [en]

    Cemented carbide is a composite material, most commonly consisting of tungsten carbide grains in a metallic matrix of cobalt. The combination of a hard ceramic phase in a ductile metallic matrix combines high hardness and ability to withstand plastic deformation with toughness to avoid cracking and fracturing. Since these properties are very important in rock drilling, cemented carbides are frequently used in such applications. In earlier work, it was found that granite in sliding contact with considerably harder cemented carbides not only results in plastic deformation of the cemented carbide composite, but also in plastic deformation of some of the individual WC grains. The latter observation is remarkable, since even the two hardest granite constituents (quartz and feldspar) are significantly softer than the WC grains. This tendency to plastic deformation of the WC grains was found to increase with increasing WC grain size. The present investigation aims to increase the understanding of plastic deformation of cemented carbides in general, and the individual WC grains in particular, in a situation representative for the rock drilling application. The emphasis is put on explaining the seemingly paradoxical fact that a nominally softer counter material is able to plastically deform a harder constituent in a composite material. The experimental work is based on a scratch test set-up, where a rock crystal tip slides against a fine polished cemented carbide surface under well-controlled contact conditions. The deformation and wear mechanisms of the cemented carbide are evaluated on the sub-micrometer scale; using high resolution FEG-SEM, EDS, EBSD, BIB and FIB cross-sectioning. The size of the Co-pockets, together with the shape and size of WC grains, turned out to be decisive factors in determining the degree of carbide deformation. The results are discussed with respect to their industrial importance, including rock drilling.

  • 5.
    Heinrichs, J
    et al.
    Uppsala Universitet.
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Jacobson, S
    Uppsala Universitet.
    Soft rock scratches hard cemented carbide2015In: Proceedings of Wear of Materials, 2015Conference paper (Refereed)
  • 6.
    Heinrichs, J
    et al.
    Uppsala Universitet.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Materials Technology. Uppsala universitet.
    Jacobson, S
    Uppsala Universitet.
    Influence of hardness and microstructure on the mechanisms of deformation and wear of cemented carbides for rock drilling2014In: Proceedings of 16th Nordic Conference on Tribology, Aarhus, Denmark, June 10-13, 2014, 2014Conference paper (Refereed)
  • 7.
    Olsson, Mikael
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Heinrichs, J
    Uppsala Universitet.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Jacobson, S
    Uppsala Universitet.
    On the relevance of hardness as a material parameter in the deformation and wear of  cemented carbides in rock drilling2014Conference paper (Refereed)
  • 8.
    Olsson, Mikael
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Heinrichs, J
    Uppsala Universitet.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Jacobson, S
    Uppsala Universitet.
    Towards a better understanding of the wear of cemented carbide drill bit inserts in rock drilling2014Conference paper (Other academic)
  • 9.
    Olsson, Mikael
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Heinrichs, Jannica
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Jacobson, Staffan
    Initial degradation of cemented carbides for rock drilling: model studies of the tribological contact against rock2015In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 52, p. 104-113Article in journal (Refereed)
    Abstract [en]

    Hardness and fracture toughness are often used as the prime material parameters to characterise cemented carbides used in rock drilling. However, the deformation and wear of cemented carbide are too complicated to be described by these parameters alone. The cemented carbide and the wearing rock mineral are both composite materials, containing phases with widely varying hardness. Moreover, the deformation behaviour of the individual phases may be strongly anisotropic, as for the WC grains in the cemented carbide. The wear of the cemented carbide typically occurs on the scale of individual grains or smaller. Contrastingly, the hardness stated for both is typically a macroscopic value, averaged over numerous grains, orientations, etc. The present investigation aims to contribute to the understanding of the relations between microstructure, properties and wear mechanisms of cemented carbide buttons in rock drilling. It is focused on the role of scale of deformation in relation to size of the different phases of the cemented carbide. This is achieved by simplifying the contact situation of the rock drill button to a single stylus sliding contact between a granite stylus and a polished cemented carbide surface. The deformation and wear of this well controlled contact is then evaluated on the sub-micrometer scale; using high resolution FEG-SEM with EBSD, FIB cross-sectioning and AFM. The results show that even an extremely local deformation, such as slip within individual WC grains, affects the tribological contact, and that the nominally much softer granite may cause deformation both within individual WC grains, and on the composite scale. The results are discussed with respect to their significance for wear of cemented carbides in rock drilling. (C) 2015 Elsevier Ltd. All rights reserved.

  • 10.
    Olsson, Mikael
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology. Ångström Tribomaterials Group, Uppsala University.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Heinrichs, J.
    Bengtsson, M.
    Jacobson, S.
    Surface degradation mechanisms of cemented carbide drill buttons in iron ore rock drilling2017In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 388-389, p. 81-92Article in journal (Refereed)
    Abstract [en]

    The wear behavior of cemented carbide rock drill buttons is influenced by many factors, which include the composition and microstructure of the cemented carbide material, the nature of the rock material, and the conditions of the rock drilling operation. Depending on the type of rock and on the drilling procedure used, the cemented carbide is exposed to substantially differing mechanical and thermal conditions. In the present study, the surface degradation and wear mechanisms of cemented carbide drill buttons exposed to iron ore rock drilling have been characterized based on a combination of high resolution scanning electron microscopy (SEM), focused ion beam cross-sectioning (FIB), energy-dispersive X-ray spectroscopy (EDS) and electron back scatter diffraction (EBSD).The results show a significant difference in surface degradation and wear between the front and peripheral buttons of the drill bits. While the front buttons display a relatively smooth worn surface with shallow surface craters the peripheral buttons display a reptile skin pattern, i.e. plateaus, 200-300. μm in diameter, separated by valleys, typically 40-50. μm wide and 15-30. μm deep, The reptile skin pattern is obtained in regions where the peripheral buttons are in sliding contact against the drill hole walls and exposed to high surface temperatures caused by the frictional heating. The results indicate that the reptile skin pattern is related to friction induced thermal stresses rather than mechanical contact stresses, i.e. the reptile skin pattern is formed due to thermal fatigue, rather than mechanical fatigue, caused by the cyclic frictional heating generated at the cemented carbide button/iron ore interface.

  • 11.
    Olsson, Mikael
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Heinrichs, Jannica
    Uppsala University.
    Bengtsson, Maria
    LKAB Wassara AB.
    Jacobson, Staffan
    Uppsala University.
    Surface degradation mechanisms of cemented carbide drill buttons exposed to iron ore rock drilling2016In: Proceedings of the 17th Nordic Symposium on Tribology - Nordtrib 2016, 2016Conference paper (Refereed)
    Abstract [en]

    The wear behavior of cemented carbide rock drill buttons is influenced by many factors, which include the composition and microstructure of the cemented carbide material, plus the conditions of the rock drilling operation, such as drilling parameters, drill button geometry and the nature of the rock material. Depending on the type of rock and on the drilling procedure used, the cemented carbide is exposed to substantially differing mechanical and thermal conditions. Under conditions of high mechanical stress and high temperatures, typical for drilling in highly abrasive rocks such as granite, the worn cemented carbide buttons are usually very smooth, with the roughness limited to within the size of individual WC grains. When drilling under conditions of moderate mechanical stress and high temperatures, typical for drilling in low-abrasive rock, such as ores with e.g. magnetite, the surface damage of the buttons usually includes a macroscopic surface wear pattern, commonly referred to as “reptile skin”, in an otherwise smooth surface. The crack growth associated to the valleys of the reptile skin pattern eventually leads to catastrophic fracture of the button, unless the cracked surface layer is repeatedly ground off before the cracks grow too deep. So despite the low general wear rate, the wear life of drill buttons becomes severely restricted by the surface cracks. The present study focuses on revealing the degradation mechanisms behind the formation of the reptile skin. This is done by analyzing drill buttons exposed to different stages of degradation and wear from drilling in iron ore. The work is based on a combination of high resolution scanning electron microscopy (SEM), focused ion beam microscopy (FIB), energy-dispersive X-ray spectroscopy (EDS) and electron back scatter diffraction (EBSD).

  • 12.
    Surreddi, Kumar Babu
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Norgren, Susanne
    Sandvik Mining and Rock Technology, Rock Tools division, Sweden; Department of Engineering Sciences, Uppsala University, Sweden.
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Characterization of surface degradation and wear damage Of cemented carbide in rock drilling2018In: The 18th Nordic Symposium on Tribology – NORDTRIB 2018 / [ed] Prof. Staffan Jacobson, 2018Conference paper (Other academic)
    Abstract [en]

    In this work, worn top hammer drill bit buttons after underground drifting in Granodiorite are analysed using scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and electron backscatter diffraction (EBSD) to understand the dominant surface failure and wear mechanisms on the flank wear land region, i.e. the outer side of the gauge row cemented carbide buttons. SEM shows that the worn surface of the flank wear land is partly covered with islands of a thin rock material transfer layer and that the exposed cemented carbide show deformed, cracked and fragmented WC grains. AES gives that the transferred rock material is mainly located on the surface but may penetrate into cemented carbide microstructure to a depth of 1-2 WC grain diameters. Finally, EBSD reveals that the deformation of the cemented carbide in the flank wear land region is located to a thin zone, about ~10 μm in depth.

  • 13.
    Yvell, Karin
    Dalarna University, School of Technology and Business Studies, Materials Technology. KTH, Materialvetenskap.
    Experimental Studies of Deformation Structures in Stainless Steels using EBSD2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, the focus has been the study of deformation structures in stainless steels by using electron backscatter diffraction (EBSD). Via increased knowledge of the evolution of the substructure during deformation, the design and control of the manufacturing process can be improved.

    A relation was found between the active deformation mechanisms, the evolution of low angle boundaries (LABs) and the strain hardening rate. When deformation twinning was an active deformation mechanism in an austenitic stainless steel with lower stacking fault energy (SFE), the strain hardening rate was maintained up to large strains due to formation of LABs. The deformation twin boundaries acted as new obstacles for dislocation slip which in turn increased the formation of LABs even further. During deformation by slip in an austenitic stainless steel with a higher SFE, the strain hardening rate instead decreased when LABs were formed. A high value of SFE promotes dislocation cross slip which in turn increases annihilation of dislocations leading to a minor increase in LAB formation.

    Deformation structures formed in surface grains during in situ tensile tests were found to develop at lower strains than in bulk grains obtained from interrupted conventional tensile tests. This behavior is consistent with the fact that dislocations sources and deformation twinning operate at approximately half the stress on a free surface as compared to the bulk.

    The deformation structures were quantified by measuring size distributions for entities bounded by LABs and high angle boundaries (HABs). The size distributions were found to be well described by bimodal lognormal distribution functions. The average size for the distribution of small grains and subgrains correlated well with the mean free distance of dislocation slip and to the strain hardening.

  • 14.
    Yvell, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology. KTH, Materialvetenskap.
    Engberg, Göran
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Deformation structures in a duplex stainless steel2018In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 941, p. 176-181Article in journal (Refereed)
    Abstract [en]

    The evolution of the deformation structure with strain has been studied using electron backscatter diffraction (EBSD). Samples from interrupted uniaxial tensile tests and from a cyclic tension/compression test were investigated. The evolution of low angle boundaries (LABs) was studied using boundary maps and by measuring the LAB density. From calculations of local misorientations, smaller orientation changes in the substructure can be illustrated. The different orientations developed with strain within a grain, due to operation of different slip systems in different parts of the grain, were studied using a misorientation profile showing substantial orientation changes after a true strain of 0.24. The texture evolution with increasing strain was followed by using inverse pole figures (IPFs). The observed substructure development in the ferritic and austenitic phases could be successfully correlated with the stress-strain curve from a tensile test. LABs were first observed in the different phases when the strain hardening rate changed in appearance indicating that cross slip started to operate as a significant dislocation recovery mechanism. The evolution of the deformation structure is concluded to occur in a similar manner in the austenitic and ferritic phases but with different texture evolution for the two phases.

  • 15.
    Yvell, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Engberg, Göran
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Microstructure evolution in an austenitic stainless steel during wire rolling2013In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 753, p. 407-410Article in journal (Refereed)
    Abstract [en]

    Material characterization is of great importance for example to improve and further develop physically based models for predicting the microstructural evolution in steels during and after hot deformation. The aim of this study was to characterize the microstructure evolution during wire rod rolling of an austenitic stainless steel of type AISI 304L in a wire rod block, consisting of eight pairs of rolls, using electron backscatter diffraction. The investigation showed that the grain size in the center of the bar decreases during the first four passes. The grain size decrease from 6.5 Όm after the first roll pass down to 2 Όm, and only small changes was measured in the overall grain size during the last four passes. The subgrain size adopts an almost constant size of 0.9 Όm from the second until the fifth roll pass. During the first 3 passes almost no recrystallization is observed and strain accumulates. Partial recrystallization then starts and for the last 3 passes the recrystallization is almost complete and the texture is nearly random. © (2013) Trans Tech Publications, Switzerland.

  • 16.
    Yvell, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Grehk, T. M.
    Engberg, Göran
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Microstructure characterization of 316L deformed at high strain rates using EBSD2016In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 122, p. 14-21Article in journal (Refereed)
    Abstract [en]

    Specimens from split Hopkinson pressure bar experiments, at strain rates between ~ 1000–9000 s− 1 at room temperature and 500 °C, have been studied using electron backscatter diffraction. No significant differences in the microstructures were observed at different strain rates, but were observed for different strains and temperatures. Size distribution for subgrains with boundary misorientations > 2° can be described as a bimodal lognormal area distribution. The distributions were found to change due to deformation. Part of the distribution describing the large subgrains decreased while the distribution for the small subgrains increased. This is in accordance with deformation being heterogeneous and successively spreading into the undeformed part of individual grains. The variation of the average size for the small subgrain distribution varies with strain but not with strain rate in the tested interval. The mean free distance for dislocation slip, interpreted here as the average size of the distribution of small subgrains, displays a variation with plastic strain which is in accordance with the different stages in the stress-strain curves. The rate of deformation hardening in the linear hardening range is accurately calculated using the variation of the small subgrain size with strain.

  • 17.
    Yvell, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Grehk, T. M.
    Hedström, P.
    Borgenstam, A.
    Engberg, Göran
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    EBSD analysis of surface and bulk microstructure evolution during interrupted tensile testing of a Fe-19Cr-12Ni alloy2018In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 141, p. 8-18Article in journal (Refereed)
    Abstract [en]

    Abstract The microstructure evolution in both surface and bulk grains in a pure Fe-19Cr-12Ni alloy has been analyzed using electron backscatter diffraction after tensile testing interrupted at different strains. Surface grains were studied during in situ tensile testing performed in a scanning electron microscope, whereas bulk grains were studied after conventional tensile testing. The evolution of the deformation structure in surface and bulk grains displays a strong resemblance but the strain needed to obtain a similar deformation structure is lower in the case of surface grains. Both slip and twinning are observed to be important deformation mechanisms, whereas deformation-induced martensite formation is of minor importance. Since the stacking fault energy (SFE) is low, 17mJ/m2, dynamic recovery by cross slip of un-dissociated dislocations is unfavorable. This reduces the annihilation of dislocations which in turn leads to a significant increase of low angle boundaries with increasing strain. The low SFE also favors formation of deformation twins which reduces the slip distance, leading to a hardening similar to the Hall-Petch relation. The combination of a low ability for cross-slip and a reduced slip distance caused by twinning is concluded to be the main reason for maintaining a high strain-hardening rate up to strains close to necking.

  • 18.
    Yvell, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Grehk, T. M.
    Hedström, P.
    Borgenstam, A.
    Engberg, Göran
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Microstructure development in a high-nickel austenitic stainless steel using EBSD during in situ tensile deformation2018In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 135, no Supplement C, p. 228-237Article in journal (Refereed)
    Abstract [en]

    Plastic deformation of surface grains has been observed by electron backscatter diffraction technique during in situ tensile testing of a high-nickel austenitic stainless steel. The evolution of low- and high-angle boundaries as well as the orientation changes within individual grains has been studied. The number of low-angle boundaries and their respective misorientation increases with increasing strain and some of them also evolve into high-angle boundaries leading to grain fragmentation. The annealing twin boundaries successively lose their integrity with increasing strain. The changes in individual grains are characterized by an increasing spread of orientations and by grains moving towards more stable orientations with 〈111〉 or 〈001〉 parallel to the tensile direction. No deformation twins were observed and deformation was assumed to be caused by dislocation slip only.

  • 19.
    Yvell, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Lindgren, Michael
    Bexell, Ulf
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    A microstructural investigation of roll formed austenitic stainless steel2013In: Sheet metal 2013: Key engineering metals, 2013, Vol. 549, p. 364-371Conference paper (Refereed)
    Abstract [en]

    Due to high production rates and the possibility to form complex geometries roll forming has become an increasingly popular forming process for sheet metal. Increasing quantities of high strength steels are used today but can be difficult to form due to their low ductility. One way to partly overcome this problem is to heat the steel in the forming area thus locally increasing the ductility. In the present study partially heated cold rolled high strength AISI 301 type austenitic stainless steel was investigated using electron backscattered diffraction (EBSD), and the results were compared to microhardness measurements. The results show that partial heating will give an almost complete reverse martensite transformation, i.e. martensite (alpha') transforms to austenite (gamma), close to the surfaces and grain growth in the middle of the steel sheet. The extension of the heat affected zone can be determined using either microhardness or EBSD measurements. Both these measurements can be used to determine the position of the neutral layer after roll forming. The hardness measurement cannot distinguish between microstructural features but the results are in good agreement with the EBSD results for volume fraction of alpha'-martensite. A major advantage of using EBSD is the possibility to characterize and follow the microstructural development when heating and roll forming.

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