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  • 101.
    Anderberg, Staffan
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering.
    Pejryd, Lars
    3Production Technology Centre, Innovatum AB.
    A survey of metal working companies’ readiness for process planning performance measurements2009In: IEEE International Conference on Industrial Engineering and Engineering Management, IEEM 8-11 sep, 2009, Hong-Kong, 2009, p. 1910-1914Conference paper (Refereed)
    Abstract [en]

    The paper presents an investigation regarding the potential and the readiness for implementing performance indicators and performance measurement systems of the process planning work for metal working companies. The paper is based on a questionnaire survey distributed to process planners in the Swedish metal working industry. The main outcome of the investigation is a foundation for understanding the implementation of performance measures of the process planning work for CNC machining. The survey revealed a few strengths and short comings in the studied companies.

  • 102. Andersson, A. J.
    et al.
    Andersson, Margareta A.T.
    KTH, Superseded Departments, Materials Science and Engineering.
    Jonsson, P. G.
    Use of an optimisation model for the burden calculation for the blast furnace process2004In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 33, no 3, p. 172-182Article in journal (Refereed)
    Abstract [en]

    The aim of a burden calculation in the blast furnace process is to compute the amounts of burden materials to be charged for obtaining desired hot-metal and slag composition. Burden calculations are normally based on trial-and-error instead of optimisation. In this study, the use of an optimisation model for a typical blast furnace operation is presented. The yield factors of some components, such as Mn, Si, S, P and V, used in the model have been determined. The more common distribution coefficients have also been studied. Both the yield factor and distribution coefficient values were generally good and showed stable behaviour for repeated periods under similar operational conditions. In this study, the model was found to be an excellent tool for determining burden material amounts and hot-metal and slag compositions for a blast furnace under steady and normal operation conditions. Using an optimising burden calculation model is time efficient, because it demands only 1 calculation procedure instead of a couple calculations as in the case with a trial-and-error method.

  • 103.
    Andersson, Annika
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Andersson, Margareta A.T.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär G
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    A study of some elemental distributions between slag and hot metal during tapping of the blast furnace2004In: Steel research, ISSN 0177-4832, Vol. 75, no 5, p. 294-301Article in journal (Refereed)
    Abstract [en]

    This paper investigates the distribution of elements between slag and hot metal from a blast furnace through calculation of distribution coefficients from actual production data. First, samples of slag and hot metal tapped from a commercial blast furnace were taken continually at 10-minute intervals for a production period of 68 hours. Distribution coefficients of manganese, silicon, sulphur and vanadium were then calculated from the results of the sample analyses. A major conclusion drawn from examination of the results was that the behaviour of the studied elements was as could be expected when approaching the equilibrium reactions from thermodynamic theory. The distributions of the elements in the slag-metal system showed clear tendencies which did not appear to be influenced by the operational conditions of the furnace. For example, for manganese, vanadium and sulphur, it was found that a higher basicity led to a decreased distribution coefficient L-Mn and L-V, but an increased L-S, which is according to theory. Another observed relationship was that slag basicity increased with an increased carbon content in the hot metal, which indicated that SiO2 was reduced to [Si] when the oxygen potential decreased. Furthermore, it was found that sulphur and silica behaviour likened that of acidic slag components, while the manganese oxide and vanadium oxide behaviour was similar to that of basic slag components.

  • 104. Andersson, Annika J.
    et al.
    Andersson, Margareta A. T.
    KTH, Superseded Departments, Materials Science and Engineering.
    Jönsson, Pär G.
    KTH, Superseded Departments, Materials Science and Engineering.
    Variation in hot metal and stag composition during tapping of blast furnace2004In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 31, no 3, p. 216-226Article in journal (Refereed)
    Abstract [en]

    To determine the quality of the hot metal and the thermal conditions inside the blast furnace, the composition of the hot metal and slag must be known. Obtaining representative metal and slag samples during tapping is thus highly important to blast furnace operation. The study covered in the present report focused on hot metal and slag composition variation during tapping from a commercial blast furnace. From the results, optimal sampling time points for obtaining elemental concentrations that can be taken as representative for the whole tapping sequence were identified. It was furthermore concluded, that the reliability of hot metal composition data is significantly improved by averaging elemental concentrations determined from two samples, each taken at a particular time point. One sampling, however, was found to be adequate for slag. Results from the study also showed a fairly strong correlation between amounts of silicon and carbon, sulphur and carbon, and silicon and sulphur in the hot metal, while a weaker correlation between hot metal temperature and each of these elements was observed.

  • 105.
    Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Characterization and Upgrading of a Low Zinc-Containing and Fine Blast Furnace Sludge: A Multi-Objective Analysis2017In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 57, no 2, p. 262-271Article in journal (Refereed)
  • 106.
    Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Characterization and Upgrading of Ore Based Steelmaking Sludges2015In: COM 2015: Conference of Metallurgists, 2015Conference paper (Other academic)
  • 107.
    Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Characterization of Blast Furnace Sludge and Upgrading Using Physical Separation and Leaching2017Conference paper (Refereed)
    Abstract [en]

    The on-site sinter plants of the Swedish ore based steel industry are all closed. Instead of using sinter, the blast furnaces (BF) operate on iron ore pellets and the major part of the recycling of in-plant residues is realized via cold bonded briquettes charged to the BF. Cost of raw materials and energy continuously drives the work towards an increased recycling of in plant residues. The major part of the zinc entering the BF leaves through the top gas ending up in the BF dust and sludge. The recycling of all the BF dust back to the BF leaves the BF sludge as the main bleed of zinc out of the system. In order to utilize the iron and carbon content of the sludge, means to remove zinc is required prior to recycling via the briquette. In the present work, blast furnace sludge has been characterized. Using the characterization as standpoint, different operations for zinc removal was suggested and studied in laboratory scale. Zinc was successfully removed using a hydrometallurgical and physical separation route, respectively. A successful dezincing operation would enable the recycling of the sludge. This would improve the material- and energy efficiency and substantially decrease the amount of sludge being landfilled.

  • 108.
    Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Feasible routes of blast furnace sludge upgrading in the light of its properties2016In: SCANMET V: 5th International Conference on Process Development in Iron and Steelmaking, Luleå, 12-15 June 2016, 2016Conference paper (Other academic)
  • 109.
    Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Morcel, Adeline
    Swerea MEFOS.
    Gullberg, Amanda
    Swerea MEFOS.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Central Metallurgical Research and Development Institute, Helwan.
    Upgrading and Recycling of Blast Furnace Sludge2017Conference paper (Other academic)
  • 110.
    Andersson, Charlotte
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Thermal diffusivity measurements in magnetite based iron ore pellets2011In: Proceedings: METEC InSteelCon 2011 : Düsseldorf, Germany, CCD Congress Center Düsseldorf, 27th June - 1st July, 2011 ; it unites for international congresses/conferences under one roof: ECIC, 6th European Coke and Ironmaking Congress; ECCC, 7th European Continuous Casting Conference; EECRsteel, 1st International Conference on Energy Efficiency and CO2 Reduction in the Steel Industry; STEELSIM, 4th International Conference on Modelling and Simulation of Metallurgical Processes in Steelmaking, Düsseldorf, 2011Conference paper (Refereed)
  • 111. Andersson, Charlotte
    et al.
    Björkman, Bo
    Engström, Fredrik
    Mostaghel, Sina
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    The need for fundamental measurements for a sustainable extraction of metals2010Conference paper (Refereed)
  • 112.
    Andersson, Charlotte
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Engström, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Mostaghel, Sina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    The need for fundamental measurements for a sustainable extraction of metals2011In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 120, no 2, p. 199-204Article in journal (Refereed)
    Abstract [en]

    The increased need for efficient material processing and efficient utilisation of more complex raw materials and the need for recycling or reusing byproduct and waste streams, are all increased challenges in material processing. To cope with these challenges, there is a need for new basic physical and thermodynamic data. The present paper gives four examples, as well as preliminary data, of areas where increased knowledge of fundamental parameters will increase the possibility for a sustainable extraction of metals. The examples include measurement of solubility of pure individual slag minerals, determination of distribution of leachable elements between different mineralogical phases in slag, influence of alumina on liquidus temperature of a copper slag and thermal diffusivity measurements in magnetite based iron ore pellets, all important in different ways to increase the sustainability of the respective materials involved

  • 113.
    Andersson, Daniel C.
    et al.
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.), Solid Mechanics (Div.).
    Lindskog, Per
    Staf, Hjalmar
    Larsson, Per-Lennart
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.), Solid Mechanics (Div.).
    A Numerical Study of Material Parameter Sensitivity in the Production of Hard Metal Components Using Powder Compaction2014In: Journal of materials engineering and performance (Print), ISSN 1059-9495, E-ISSN 1544-1024, Vol. 23, no 6, p. 2199-2208Article in journal (Refereed)
    Abstract [en]

    Modeling of hard metal powder inserts is analyzed based on a continuum mechanics approach. In particular, one commonly used cutting insert geometry is studied. For a given advanced constitutive description of the powder material, the material parameter space required to accurately model the mechanical behavior is determined. These findings are then compared with the corresponding parameter space that can possibly be determined from a combined numerical/experimental analysis of uniaxial die powder compaction utilizing inverse modeling. The analysis is pertinent to a particular WC/Co powder and the finite element method is used in the numerical investigations of the mechanical behavior of the cutting insert.

  • 114.
    Andersson, Emma
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sichen, Du
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The Effect of CaF2 in the Slag in Ladle Refining2009In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 80, no 8, p. 544-551Article in journal (Refereed)
    Abstract [en]

    Industrial experiments were conducted in ladle treatment at SSAB Oxelosund aiming at a reduction and even elimination of CaF2 as a component in synthetic slag formers. The effects of the presence of CaF2 on sulphur refining, lining wear as well as types and amount of inclusions were examined. The results of the plant trials indicated that the new slag without CaF2 had enough capacity for sulphur removal. On the other hand, the presence of CaF2 as a flux in the slag resulted in profound lining wear. It was also found that both the number and the types of non-metallic inclusions were not affected by the elimination of CaF2 from synthetic slag. The origins of different types of inclusions were also analysed on the basis of the experimental results. The analysis supported the finding that the presence of CaF2 had little effect on inclusions.

  • 115.
    Andersson, Erik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The effect of argon stirring on separation of oxidic inclusions in the ladle furnace at Sandvik Materials Technology AB2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The effect of gas stirring in the ladle furnace on inclusion content in austenitic and duplex stainless steel has been investigated at Sandvik Materials Technology AB. The effect was mainly investigated by varying duration of stirring time and intensity of stirring. Any effect on inclusion content was determined by examining total oxygen content before and after the ladle treatment, along with mapping the chemical composition, size and size distribution of the inclusions. Any effect on slag composition was also determined. The effect of gas stirring was measured on a number of heats with continuous sampling during normal production. Data regarding oxygen content during the ladle refining process and the duration of the processes was used to determine a quantifiable relationship between stirring time, stirring intensity and resulting change in oxygen content. The result of the investigation was recommendations regarding the use of varied stirring intensities and duration of gas stirring for achieving negative net loss in oxygen content before and after ladle treatment.

  • 116.
    Andersson, Erik
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Johansson, Andreas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The effect of driving force in Gibbs energy on the fraction of martensite2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The background to this bachelor thesis is an on-going project within the VINN Excellence Center Hero-m. The task in this thesis is to perform a literature survey about the martensite transformation and investigate how the resulting fraction depends on cooling below the Ms-temperature. Instead of calculating the undercooling for each of the known fractions of martensite the driving force will be evaluated. Several efforts have been made through the years to describe the relationships between fraction transformed austenite and temperature. The approaches to the first models were empirical and derived from collections of data regarding the amount of retained austenite at different quenching temperatures. Lately, studies have been made to derive a thermodynamical relationship using how the Gibbs energy is affected by increments in volume transformed austenite. Two equations are derived by calculating the resulting driving force at different known quenching temperatures and the respective percentage transformed martensite found in previous works. The data for the steels used show a characteristic slope when linearised. A trend for the steels which have a high characteristic slope is that they also have a high Ms temperature, and the steels which have a low characteristic slope tend to have a low Ms. Previous relationships which describe the martensitic transformation have considered the importance of the Ms temperature only in it being a starting temperature for the transformation. To further incorporate the Ms temperature in the equations presented, further research of the martensitic transformation is required. The approach in this thesis of using thermodynamically calculated data is a base for further investigation of the range of the martensite transformation.

  • 117. Andersson, G.
    et al.
    Seetharaman, Seshadri
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Process Science.
    "Steel eco-cycle" - A Swedish cross-pollination environmental research program2013In: Materials Science and Technology Conference and Exhibition 2013, MS and T 2013, Warrendale , 2013, p. 1784-1791Conference paper (Refereed)
    Abstract [en]

    In 2004, Swedish steel industry launched the first truly holistic research program in one of the world's most energy intensive industries with the aim to drastically increase the energy and resource efficiency by governing and reinforce (closing) the loop in the steel life cycle. The inter-disciplinary approach of the program has led to a significant cross-pollination in environmental steel technology and related areas apart from the impact in the educational field. The program, alongside the development of resource-efficient production of steel, has led to offshoots in aluminium remelting industry, recovery of rare earths from magnetic scrap and recovery of lead from CRT glasses. The research efforts led to the successful recovery of vanadium and magnetically important manganese nanoferrites from (waste) steel slags. The results, in fact, even provide insights into declarations of human attitudes, future raw material prognoses, process optimizations and pilot plant trials along with instrument and model developments.

  • 118.
    Andersson, Henrik C.M.
    et al.
    Swedish Institute for Metals Research.
    Sandström, Rolf
    Swedish Institute for Metals Research.
    Segle, P.
    SAQ Kontroll.
    Andersson, Peter
    SAQ Kontroll.
    Creep crackgrowth in ex service weld metal of 0.5CrMoV1999In: Cape 99: Wilderness, Cape province, South Africa, 12-16 April (1999), 1999Conference paper (Refereed)
    Abstract [en]

    Accurate assessment of the integrity of high temperature components will be of ever increasing importance. The reason for this is that many power plants have reached and exceeded their design life and the number of detected defects increases. This is accentuated by the improvement of the methods for non-destructive testing which means that more and smaller defects will be detected. The possibility to assess the influence of defects on the integrity of high temperature components, will be of vital importance to maintain safe and cost effective power plants.

    The aim of the present work is to increase the understanding of the influence of service exposure on the remaining life of components in a high temperature plant. The investigation aims to creep test exserviceweld material, 14MoV 6 3, from a Swedish power plant. Thematerial has been in service for a period of about 80 000 hours at atemperature of 530-540 °C and with a nominal hoop stress of 52MPa.Both uniaxial and compact tension creep tests have been performedat a temperature of 550 °C. The stress range used was between 130MPa and 170 MPa for the uniaxial creep tests. For the creep crack growth tests the reference stress was ranging between 122 MPa and146 MPa.

    A remaining life assessment according to the R5 procedure is included, where material data from the present experimental study is used. The analysis suggests that a defect or a crack with a depth of 2 mm and a length of 5 mm can be left unattended for a season of service under the condition that the service parameters are not changed. A comparison with the assessment of cracks, found in the same plant as the material for the experimental studies came from, and their known extension during service, is included. A parametric study where load level and type of initial defect/crack are varied is also included.

  • 119.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Weldability of Ni-based Superalloys2014In: 8th International Symposium on Superalloy 718 and Derivatives: Conference Proceedings / [ed] Ott, E., Banik, A., Andersson, J., Dempster, I., Gabb, T., Groh, J., Heck, K., Helmink, R., Liu, X. & Wusatowska-Sarnek, A., Hoboken, NJ, USA: John Wiley & Sons, 2014, p. 249-262Conference paper (Refereed)
  • 120.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Raza, Shahzad
    Department of Materials Science and Engineering, Royal Institute of Technology.
    Eliasson, Anders
    KTH, Department of Materials Science and Engineering, Royal Institute of Technology.
    Surreddi, Kumar Babu
    Chalmers University of Technology, Department of Materials and Manufacturing Technology.
    Solidification of Alloy 718, ATI 718Plus and Waspaloy2014In: 8th International Symposium on Superalloy 718 and Derivatives: Conference Proceedings / [ed] Ott, E., Banik, A., Andersson, J., Dempster, I., Gabb, T., Groh, J., Heck, K., Helmink, R., Liu, X. & Wusatowska-Sarnek, A, Hoboken, NJ, USA: John Wiley & Sons, 2014, p. 181-192Conference paper (Refereed)
  • 121.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes. Department of Materials Technology, Volvo Aero Corporation, Trollha¨ttan, Sweden and Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Department of Materials Technology, Volvo Aero Corporation, Trollha¨ttan, Sweden and Chalmers University of Technology, Gothenburg, Sweden.
    Repair welding of wrought superalloys: Alloy 718, Allvac 718Plus and Waspaloy2012In: Science and Technology of Welding and Joining, ISSN 1362-1718, Vol. 17, no 1, p. 49-59Article in journal (Refereed)
    Abstract [en]

    The ability to weld repair three precipitation hardening superalloys, i.e. Alloy 718, Allvac 718Plus and Waspaloy, with gas tungsten arc welding, is compared in this study. Four different solution heat treatment conditions for each material were examined: Alloy 718 and Allvac 718Plus heat treated at 954uC–1 h, 982uC–1 h, 954uC–15 h and 1020uC–1 h and Waspaloy for 4 h at 996uC, 1010uC, 1040uC and at 1080uC. By metallography, the total number of cracks was evaluated in both the heat affected zone and the fusion zone, which made it possible to consistently rate the repair weldability of these three materials. Alloy 718 was significantly the best one, with Allvac 718Plus slightly better than Waspaloy. As expected, the solution heat treatment conditions only affected the heat affected zone cracking behaviour.

  • 122.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Sjöberg, G.
    Brederholm, A.
    Hänninen, H.
    Solidification Cracking of Alloy Allvac 718Plus and Alloy 718 at Transvarestraint Testing2010In: EPD Congress 2008: Proceedings of Sessions and Symposia Sponsored by the Extraction and Processing Division (EPD) / [ed] Stanley M. Howard, Wiley-Blackwell, 2010, p. 157-169Conference paper (Refereed)
  • 123.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Sjöberg, G.
    Chaturvedi, M.
    Hot Ductility Study of Haynes 282 Superalloy2010In: Superalloy 718 and Derivatives: Proceedings of the 7th International Symposium on Superalloy 718 and Derivatives / [ed] E. A. Ott, J. R. Groh, A. Banik, I. Dempster, T. P. Gabb, R. Helmink, X. Liu, A. Mitchell, G. P. Sjöberg and A. Wusatowska-Sarnek, The Minerals, Metals, and Materials Society, 2010, p. 539-554Conference paper (Refereed)
  • 124.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Sjöberg, G.
    Hatami, S.
    Notch Sensitivity and Intergranular Crack Growth in the Allvac 718Plus Superalloy2007In: XVIII International Symposium on Air Breathing Engines (ISABE): Beijing, China, 2-7 September 2007, 2007, p. n.1293-Conference paper (Refereed)
  • 125.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes. Volvo Aero Corporation, Trollhättan, Sweden och Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Volvo Aero Corporation, Trollhättan, Sweden och Chalmers University of Technology, Gothenburg, Sweden.
    Hänninen, H.
    Aalto University School of Science and Technology, Espoo, Finland.
    Metallurgical Response of Electron Beam Welded Allvac® 718Plus™2011In: Hot Cracking Phenomena in Welds III / [ed] Lippold, J., Böllinghaus, T. and Cross C. E., Springer Berlin/Heidelberg, 2011, p. 415-428Conference paper (Refereed)
    Abstract [en]

    Electron beam welding of forged Allvac 718Plus superalloy has been carried out without any visible cracks in weld cross-sections. Healed cracks in the heat affected zone were, however, seen in most cross-sections with the healing as well as the cracking believed to be due to the constitutional liquation of the δ-phase. The δ-phase undergoes constitutional liquation in the Heat Affected Zone (HAZ) and consequently decreases the ductility of the material and renders cracks in the HAZ but due to the large amount of eutectic liquid produced at the same time the healing of the opened cracks takes place.

  • 126.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes. Volvo Aero Corporation, Materials Technology Department, Trollhättan, Sweden och Chalmers University of Technology, Department of Materials and Manufacturing Technology, Göteborg,Sweden.
    Sjöberg, G.
    Volvo Aero Corporation, Materials Technology Department, Trollhättan, Sweden och Chalmers University of Technology, Department of Materials and Manufacturing Technology, Göteborg, Sweden.
    Larsson, J.
    Chalmers University of Technology, Department of Materials and Manufacturing Technology, Göteborg,Sweden.
    Investigation of Homogenization and its Influence on the Repair Welding of Cast Allvac 718Plus(®)2010In: Superalloy 718 and Derivatives: Proceedings of the 7th International Symposium on Superalloy 718 and Derivatives / [ed] E. A. Ott, J. R. Groh, A. Banik, I. Dempster, T. P. Gabb, R. Helmink, X. Liu, A. Mitchell, G. P. Sjöberg, and A. Wusatowska-Sarnek, The Minerals, Metals, and Materials Society, 2010, p. 439-454Conference paper (Refereed)
  • 127.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Sjöberg, G.
    Viskari, L.
    Brederholm, A.
    Hänninen, H.
    Knee, C.
    Hot Cracking of Allvac 718Plus, Alloy 718 and Waspaloy at Varestraint Testing2008In: 4th International Symposium on Aerospace Materials and Manufacturing Processes: Advances in Processing and Repair of Aerospace Materials 2008 / [ed] M. Jahazi, M. Elboujdaini and P. Patnaik, Montreal: Canadian Institute of Mining, Metallurgy and Petroleum, 2008, p. 401-413Conference paper (Refereed)
    Abstract [en]

    Varestraint testing together with DSC and SEM-EDX analyses have been performed as means of investigating the hot cracking susceptibility of Allvac 718Plus, alloy 718 and Waspaloy. The solidification sequences in Allvac 718Plus and alloy 718 were very similar to each other starting by an initial solidification of the gamma phase, gamma/MC reaction at around 1260°C and then finally ending the sequence by gamma/Laves eutectic reaction at around 1150°C. Waspaloy had the same solidification sequence, except no Laves phase formation takes place, and solidification started at a somewhat higher temperature as compared to alloy 718 and the solidification sequence ends by a gamma/MC reaction at around 1245°C. The total amount of hot cracking in Waspaloy was shown to be much less than that in alloy 718 and in Allvac 718Plus which is believed to be related to the presence of the Laves eutectic in the latter two alloys with corresponding larger solidification ranges. Hot cracking of 718Plus is slightly less than in 718.

  • 128.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes. Department of Materials Technology, GKN Aerospace Engine Systems, Trollhättan, Sweden och Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Department of Materials Technology, GKN Aerospace Engine Systems, Trollhättan, Sweden och Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Viskari, L.
    Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden.
    Chaturvedi, M. C.
    Department of Mechanical and Industrial Engineering, University of Manitoba, Winnipeg, MB, Canada.
    Effect of Different Solution Heat Treatments on the Hot Ductility of Superalloys: Part 3 - Waspaloy2013In: Materials Science and Technology, ISSN 0267-0836, Vol. 29, no 1, p. 43-53Article in journal (Refereed)
    Abstract [en]

    The susceptibility to heat affected zone cracking of Waspaloy has been investigated in terms of its hot ductility, measured as the reduction of area (RA). Gleeble testing with on-heating as well as on-cooling test cycles was carried out to illuminate the influence of different 4 h solution heat treatments between 996 and 1080°C. A ductility maximum of between 80 and 90%RA was found at 1050–1100°C for all conditions in the on-heating tests. Although the different heat treatment conditions showed similar macrohardness, the particle size and distribution of the γ′ and M23C6 phases differed, which significantly affected the on-heating ductility in the lower temperature test region. The ductile to brittle transition was initiated at 1100°C in the on-heating testing with indications of grain boundary liquation at the higher test temperatures. Ductility recovery, as measured in the on-cooling tests from 1240°C, was very limited with <30%RA for all conditions and test temperatures except for the 1080°C/4 h treatment, which exhibited 60%RA at 980°C.

  • 129.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes. Department of Materials Technology, Volvo Aero Corporation, Trollhättan, Sweden and Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Department of Materials Technology, Volvo Aero Corporation, Trollhättan, Sweden and Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Viskari, L.
    Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden.
    Chaturvedi, M.C.
    Department of Mechanical and Industrial Engineering, University of Manitoba, Winnipeg, MB, Canada.
    Effect of different solution heat treatments on hot ductility of superalloys: Part 2 – Allvac 718Plus2012In: Materials Science and Technology, ISSN 0267-0836, Vol. 28, no 6, p. 733-741Article in journal (Refereed)
    Abstract [en]

    The hot ductility of Allvac 718Plus for different solution heat treatments (954°C–15 h, 954°C–1 h, 982°C–1 h and 1050°C–3 h+954°C–1 h) has been investigated using Gleeble testing. Substantial variations in the microstructure among the heat treatments affected the Gleeble test hot ductility only to a very limited extent. Constitutional liquation of the NbC phase was found to be the main cause for the poor ductility at high testing temperatures in the on-heating cycle as well as at the lower temperatures on-cooling. Grain boundary δ phase was seen to assist the constitutional liquation of the NbC phase. Based on established evaluation criteria for Gleeble ductility testing, a ranked indicator for weldability is suggested.

  • 130.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes. Department of Materials Technology at Volvo Aero Corporation, Trollhättan, and Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Department of Materials Technology at Volvo Aero Corporation, Trollhättan, and Chalmers University of Technology, Gothenburg, Sweden.
    Viskari, L.
    Department of Microscopy and Microanalysis at Chalmers University of Technology, 41296 Gothenburg, Sweden.
    Chaturvedi, M.C.
    Department of Mechanical and Industrial Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 Canada.
    Effect of solution heat treatments on superalloys: Part 1 – alloy 7182012In: Materials Science and Technology, ISSN 0267-0836, Vol. 28, no 5, p. 609-619Article in journal (Refereed)
    Abstract [en]

    The hot ductility as measured by Gleeble testing of Alloy 718 at four different solution heat treatments (954°C/15 h, 954°C/1 h, 982°C/1 h and 1050°C/3 h+954°C/1 h) has been investigated. It is concluded that constitutional liquation of NbC assisted by δ phase takes place and deteriorates the ductility. Parameters established by analysing the ductility dependence on temperature indicate a reduced weldability of the material in the coarse grain size state (ASTM 3) while indicating an increased weldability when containing a large amount of δ phase due to a grain boundary pinning effect. The accumulation of trace elements during grain growth at the highest temperature is believed to be the cause for the observed reduced on-cooling ductility.

  • 131.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Vikström, Fredrik
    GKN Aerospace Engine Systems.
    Pettersson, Bengt
    GKN Aerospace Engine Systems.
    HIP-Densification of Alloy 718 and ATI 718Plus2014In: 8th International Symposium on Superalloy 718 and Derivatives: Conference Proceedings / [ed] Ott, E., Banik, A., Andersson, J., Dempster, I., Gabb, T., Groh, J., Heck, K., Helmink, R., Liu, X. & Wusatowska-Sarnek, A., Hoboken, NJ, USA: John Wiley & Sons, 2014, p. 425-436Conference paper (Refereed)
  • 132.
    Andersson, Margareta
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Appelberg, Jesper
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Tilliander, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Nakajima, Keiji
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Shibata, Hiroyuki
    Tohoku University, Institute of Multidisciplinary Research for Advanced Materials.
    Kitamura, Shinya
    Tohoku University, Institute of Multidisciplinary Research for Advanced Materials.
    Jonsson, Lage
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Some Aspects on Grain Refining Additions with Focus on Clogging during Casting2006In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 46, no 6, p. 814-823Article in journal (Refereed)
    Abstract [en]

    Some ideas of how to study optimum conditions for implementation of grain refining in liquid steel processing with focus on how to avoid clogging are discussed. It is assumed that the inclusions most beneficial for grain refining are known from studies by physical metallurgists. The challenge for a process metallurgist is how to provide a homogeneous distribution of grain refiners at the onset of solidification. Four different ways of providing information to succeed with this are discussed. Thermodynamic modeling can be used to predict what additions to make to create potential grain refiners, if relevant thermodynamic data is available. Mathematical fluid-flow modeling can be used to study where to add potential grain refiners. It is discussed that the tundish is the most appropriate reactor to add grain refiners, since enough time is given to a complete mixing of the grain refiner into the steel before the steel enters the mold. By using the scanning laser microscopy technique it is possible to study which potential grain refiners has the lowest attraction forces between each other. This is important in order to minimise growth of inclusions when they collide during transport in the tundish, which can lead to the formation of larger inclusions that do not serve as useful grain refiners. Finally, it is suggested that laboratory experiments are carried out in order to study the tendency for nozzle clogging, before the use of grain refiners is tested in industrial scale.

  • 133.
    Andersson, Margareta A.T.
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Hallberg, Malin
    Jonsson, Lage
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Slag-metal reactions during ladle treatment with focus on desulphurisation2002In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 29, no 3, p. 224-232Article in journal (Refereed)
    Abstract [en]

    Within several cooperative projects, KTH (Royal Institute of Technology), Ovako Steel AB, and MEFOS have investigated the desulphurisation of bearing steel during vacuum degassing. The work includes thermodynamic calculations of the slag-metal equilibrium, CFD modelling of slag-metal reactions, and plant trials. Results from the various studies are presented and discussed in this paper. Models for predicting slag properties (sulphide capacity, viscosity, and oxide activities) in liquid slags as functions of slag composition and temperature have been used for the calculation of data which have been employed in static and dynamic modelling of sulphur refining. The results from static modelling show that the method allows fast and easy evaluation of the theoretical desulphurisation conditions during degassing at Ovako Steel AB, as well as theoretical determination of the parameters that have the greatest influence on the equilibrium sulphur distribution. The conclusion from dynamic modelling is that the vacuum degassing operation can be described dynamically with the present knowledge of sulphide capacity, sulphur distribution, viscosity, and oxide activities of ladle slags if this knowledge is combined with fluid flow modelling to derive the overall kinetics. The presented model approaches have been found useful in understanding the sulphur refining process at Ovako Steel AB. The dynamic modelling concept is also believed to have potential for dynamic descriptions of other slag-metal reactions in steelmaking.

  • 134.
    Andersson, Margareta
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Hallberg, Malin
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jonsson, Lage
    KTH, Superseded Departments, Applied Process Metallurgy.
    Jönsson, Pär
    KTH, Superseded Departments, Applied Process Metallurgy.
    Slag/metal reactionsduring ladle treatment with focus on desulphurisation2000In: 6thInternational Conference on Molten Slags, Fluxes and Salts, 2000Conference paper (Refereed)
  • 135.
    Andersson, Nils
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Tilliander, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jonsson, Lage
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Fundamental decarburisation model of AOD process2013In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 40, no 5, p. 390-397Article in journal (Refereed)
    Abstract [en]

    A mathematical fluid flow model of gas injection in an argon–oxygen decarburisation (AOD) converter process has been coupled with a high temperature thermodynamic model. The current model is a further enhancement of an earlier developed three-dimensional, three-phase model, to also include some thermodynamics of the process. The model is based on fundamental transport equations and includes separate solutions for the steel, slag and the gas phases and their coupling by friction. The AOD model has been used to predict the first injection stage of decarburisation in an AOD converter. The predictions have been found to agree well with the corresponding results from an industrial process control model. One of the important observations from the simulations was that large concentration gradients of carbon exist in the AOD at an early stage and as the first injection step approaching its end the carbon gradients diminish. Also, the results show, in accordance with theory, that the local decarburisation rate is decreased at elevated pressures.

  • 136.
    Andersson, Nils
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Tilliander, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jonsson, Lage
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Investigating the effectof slag on decarburization in an AOD converter using a fundamental model2013In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 84, no 2, p. 169-177Article in journal (Refereed)
    Abstract [en]

    A high-temperature thermodynamics model has been coupled with a fundamental mathematical model describing the fluid flow, where boundary conditions were chosen based on data for an industrial AOD converter. Using this model, the effect of both slag phases (a liquid part and a solid part) on the decarburization was studied. More specifically, the separation of chromium oxide to liquid slag as well as the effect of the amount of rigid top slag (solid)on the decarburization was investigated. The liquid slag was considered with respect to the uptake of chromium oxide, while the rigid top slag was only considered with respect to the increase of the metallostatic pressure in the steel melt. The results suggest that separation of chromium oxide to liquid slag results in a decreased decarburization rate. The same conclusion can be drawn with respect to the amount of solid top slag.

  • 137.
    Andersson, Nils
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Tilliander, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jonsson, Lage
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Preliminary investigation of influence of temperature on decarburisation using fundamental AOD model2013In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 40, no 7, p. 551-558Article in journal (Refereed)
    Abstract [en]

    A high temperature thermodynamics model was earlier coupled with a fundamental mathematical model describing the fluid flow in an argon–oxygen decarburisation (AOD) converter and was initially validated for an idealised temperature description. More specifically, a linear average temperature relation was used such that the temperature would be isolated from other effects such as reactions and mixing. Thereafter, the effect of the starting temperature on the decarburisation was studied. The purpose is to provide some initial knowledge about how temperature affects the decarburisation in an AOD converter. The results suggest that the thermodynamic limit for carbon concentration after reaching the carbon removal efficiency (CRE) maxima is vertically translated downwards at higher temperatures. Furthermore, when plotting the mass ratio between CO and CO2, there is an indication of a point that may relate to a CRE maximum.

  • 138.
    Andersson, Nils Å. I.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Coupling of a fundamental mathematical fluid flow model with computational thermodynamics model to study the decarburisation2012Doctoral thesis, comprehensive summary (Other academic)
  • 139.
    Andersson, Nils Å. I.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Tilliander, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jonsson, Lage T. I.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär G.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    A fundamental decarburization model of the AOD processIn: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812Article in journal (Other academic)
  • 140.
    Andersson, Nils Å. I.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Tilliander, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jonsson, Lage T. I.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär G.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    An in-Depth Model-Based Analysis of Decarburization in the AOD Process2012In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 83, no 11, p. 1039-1052Article in journal (Refereed)
    Abstract [en]

    A previously reported flow and reaction model for an argon-oxygen decarburization converter was extended to also include a thermodynamic description. An in-depth study of the model results has been conducted to answer how concentrations of elements and species in the converter at different locations change with time. This may contribute to the understanding of the mechanisms of the refining procedure in the argon-oxygen decarburization process. The refining procedure includes several step-wise changes of an injected gas composition to higher and higher inert gas ratio, called step changes. A step change leads to a decreased partial pressure of carbon monoxide and maintains the decarburization at a higher efficiency. The results shows early and late concentration profiles for the first injection step and suggests a way to determine when a step change should be made. Moreover, the step change could be determined by calculating the carbon concentration profiles and deciding when the carbon concentration gradients start to diminish.

  • 141.
    Andersson, Nils Å. I.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Tilliander, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jonsson, Lage T. I.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär G.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Investigating the effect of slag on decarburization in an AOD coverter using a fundamental modelIn: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344XArticle in journal (Other academic)
  • 142.
    Andersson, Nils Å. I.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Tilliander, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jonsson, Lage T. I.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär G.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Preliminary investigation of temperatur dependencies on decarburization in a fundamental AOD modelIn: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812Article in journal (Other academic)
  • 143.
    Andersson, Oscar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering. KTH, Centres, XPRES, Excellence in production research.
    Budak, Nesrin
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    Melander, Arne
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering. KTH, Centres, XPRES, Excellence in production research.
    Palmquist, Niclas
    Experimental measurements and numerical simulations of distortions of overlap laser-welded thin sheet steel beam structures2017In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 61, no 5, p. 927-934Article in journal (Refereed)
    Abstract [en]

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

  • 144.
    Andersson, Sofia
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Study of Dross in Ductile Cast Iron Main Shafts2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The study of dross in ductile cast iron main shafts was performed at Global Castings Guldsmedshyttan AB and presented in this master thesis. The purpose of the study was to obtain answers to why dross defects were present in some of the foundry's casted main shafts, with the main problem located at the flange of the shaft. The chemical composition of the dross formations and which steps in the casting process that increased the dross formation were of interest. The study only included dross in main shafts manufactured at Global Castings Guldsmedshyttan AB.

    Dross particles form when elements such as Mg, Ca, Si and Mn react with O. These elements, which are highly reactive to O, are used in ductile cast irons to achieve the spheroidal graphite nodules that regulate the cast materials ductile properties. If a higher amount of dross particles has formed, the particles will start to cluster, resulting in a growing dross formation. Dross formations works as surface crack initiation points and reduces the castings fatigue strength and ductility.

    During the study it was seen that the cause of dross formations is a combination of many parameters increasing the melts exposure to O resulting in dross defects. The dross formations could be connected to worn out ladles, low melt temperatures, incorrect additions of Mg treatment, lack of an extra slag removal station and finally turbulence as the melt were poured into the mould.

    At Global Castings Guldsmedshyttan AB a greater part of the main shafts containing dross defects were a result of worn out ladles and low melt temperatures. The types of dross found in the main shaft material were mainly Mg, Ca, Si and Al which had reacted with O. S bonded with Mg and Ca was also detected in the dross formations. It was shown that the dross particles could be derived from charge material, Mg treatment and inoculation.

    To avoid dross defects the first step would be to set up an extra slag station, shorten the interval of maintenance of the ladles and to better adjust the melt temperature to the condition of the specific ladle. To minimize dross due to excess Mg a better controlled process would be recommended with an increased number of monitored manufacturing parameters.    

  • 145.
    Andersson, Stefan
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Analysis of welding in comparable steel grades: Influence of steel grade on the welding process2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis is written to examine the influence of different low carbon steel sheet materials on the GMAW welding process. During welding the properties of the base material influence the productivity of the welding process. The purpose of this thesis is to examine how the choice of material and welding speed affect the welding process and the productivity.

    A literature survey was performed to describe the welding technique and the differences in manufacturing for the sheet materials as well as the effect of alloying and welding on the sheet material. Defects in the weld and methods used to determine them are explained. Test pieces of the different sheet materials were welded with the GMAW process and examined.

    The result shows that there is a variation in the welding process regarding weld penetration. Measurements also show that welding speed and gap have little influence on the hardness of the weld and heat-affected zone and that the S355MC is more likely to suffer from a narrower toe transition radius than S355NL and S355MC Si. This and the higher area in the Y2 region for the S355MC could indicate a stronger inward flow in the weld pool during welding possibly a result of surface active agents such as oxygen and sulphur.

  • 146. Andersson, Urban
    et al.
    Engström, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Gustavsson, Håkan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Karlsson, Rolf
    Vattenfall Research & Development.
    The Turbine-99 workshops - conclusions and recommendations2004In: 22nd IAHR Symposium on Hydraulic Machinery and Systems, Stockholm, Sweden, June 29 - July 2, 2004, Stockholm: IAHR , 2004Conference paper (Other academic)
  • 147.
    Andreasson, Eskil
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Lindström, Tommy
    Lunds Universitet, SWE.
    Käck, Britta
    Altair Engineering AB, SWE.
    Malmberg, Christoffer
    Saab AB, SWE.
    Asp, Ann Magret
    Tetra Pak AB, SWE.
    Simulation of thin aluminium-foil in the packaging industry2017In: AIP Conference Proceedings / [ed] Brabazon D.,Ul Ahad I.,Naher S., American Institute of Physics Inc. , 2017, Vol. 1896, article id 160014Conference paper (Refereed)
    Abstract [en]

    This work present an approach of how to account for the anisotropic mechanical material behaviour in the simulation models of the thin aluminium foil layer (≈10 μm) used in the Packaging Industry. Furthermore, the experimental results from uniaxial tensile tests are parameterised into an analytical expression and the slope of the hardening subsequently extended way beyond the experimental data points. This in order to accommodate the locally high stresses present in the experiments at the neck formation. An analytical expression, denominated Ramberg-Osgood, is used to describe the non-linear mechanical behaviour. Moreover it is possible with a direct method to translate the experimental uniaxial tensile test results into useful numerical material model parameters in Abaqus™. In addition to this the extended material behaviour including the plastic flow i.e. hardening, valid after onset of localisation, the described procedure can also capture the microscopic events, i.e. geometrical thinning, ongoing in the deformation of the aluminium foil. This method has earlier successfully been applied by Petri Mäkelä for paperboard material [1]. The engineering sound and parameterised description of the mechanical material behaviour facilitates an efficient categorisation of different aluminium foil alloys and aid the identification of the correct anisotropic (RD/TD/45°) mechanical material behaviour derived from the physical testing. © 2017 Author(s).

  • 148.
    Andriollo, Tito
    et al.
    Department of Mechanical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
    Hellström, Kristina
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    Sonne, Mads R.
    Department of Mechanical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
    Thorborg, Jesper
    Department of Mechanical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
    Tiedje, Niels
    Department of Mechanical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
    Hattel, Jesper
    Department of Mechanical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
    Uncovering the local inelastic interactions during manufacture of ductile cast iron: How the substructure of the graphite particles can induce residual stress concentrations in the matrix2018In: Journal of the mechanics and physics of solids, ISSN 0022-5096, E-ISSN 1873-4782, Vol. 111, p. 333-357Article in journal (Refereed)
    Abstract [en]

    Recent X-ray diffraction (XRD) measurements have revealed that plastic deformation and a residual elastic strain field can be present around the graphite particles in ductile cast iron after manufacturing, probably due to some local mismatch in thermal contraction. However, as only one component of the elastic strain tensor could be obtained from the XRD data, the shape and magnitude of the associated residual stress field have remained unknown. To compensate for this and to provide theoretical insight into this unexplored topic, a combined experimental-numerical approach is presented in this paper. First, a material equivalent to the ductile cast iron matrix is manufactured and subjected to dilatometric and high-temperature tensile tests. Subsequently, a two-scale hierarchical top-down model is devised, calibrated on the basis of the collected data and used to simulate the interaction between the graphite particles and the matrix during manufacturing of the industrial part considered in the XRD study. The model indicates that, besides the viscoplastic deformation of the matrix, the effect of the inelastic deformation of the graphite has to be considered to explain the magnitude of the XRD strain. Moreover, the model shows that the large elastic strain perturbations recorded with XRD close to the graphite–matrix interface are not artifacts due to e.g. sharp gradients in chemical composition, but correspond to residual stress concentrations induced by the conical sectors forming the internal structure of the graphite particles. In contrast to common belief, these results thus suggest that ductile cast iron parts cannot be considered, in general, as stress-free at the microstructural scale. 

  • 149.
    Antti, Britt-Marie
    Luleå tekniska universitet.
    Pulpkemi och kalcitflotation1986In: Workshop i mineralteknik: Luleå 11-12 februari 1986 / [ed] Börje Sköld; Eric Forssberg, MinFo , 1986, p. 81-104Conference paper (Other academic)
  • 150.
    Antti, Britt-Marie
    et al.
    Luleå University of Technology.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Pulp chemistry in calcite flotation.: Modelling of oleate adsorption using theoretical equilibrium calculations1989In: Mining engineering, ISSN 0026-5187, Vol. 2, no 1, p. 93-109Article in journal (Refereed)
    Abstract [en]

    This paper considers the conditions required for direct flotation of calcite. Flotation experiments have been performed with oleate as the collector reagent and water glass as the dispersant and modifier. To be able to explain what happens in the flotation, solubility and adsorption experiments have been conducted parallel to, and under the same conditions as, the flotation experiments. Theoretical equilibrium calculations have been made with the help of data from the practical experiments for the purpose of modelling the adsorption experiments. With theoretical equilibrium calculations it is possible to predict that silicate ions will form complexes with calcium ions at the mineral surface.

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