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Lindgren, L.-E. & Gyhlesten Back, J. (2019). Elastic properties of ferrite and austenite in low alloy steels versus temperature and alloying. Materialia, 5, Article ID 100193.
Open this publication in new window or tab >>Elastic properties of ferrite and austenite in low alloy steels versus temperature and alloying
2019 (English)In: Materialia, ISSN 2589-1529, Vol. 5, article id 100193Article in journal (Refereed) Published
Abstract [en]

Models for elastic properties, as a function of temperature, are required when simulating various thermo-mechanical processes. A model for hypoeutectoid steels is proposed that accounts for this temperature dependency as well as the influence of alloying. The model consists of separate parts for the ferrite and austenite phases. The latter also includes a specific contribution due to ferromagnetism. The model is calibrated versus iron and evaluated against various steels.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Elastic properties, Steels, Temperature, Alloying
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-72815 (URN)10.1016/j.mtla.2018.100193 (DOI)2-s2.0-85061033793 (Scopus ID)
Available from: 2019-02-07 Created: 2019-02-07 Last updated: 2019-02-27Bibliographically approved
Olaogun, O., Edberg, J., Lindgren, L.-E., Oluwole, O. O. & Akinlabi, E. (2019). Heat transfer in cold rolling process of AA8015 alloy: a case study of 2-D FE simulation of coupled thermo-mechanical modeling. The International Journal of Advanced Manufacturing Technology, 100(9-12), 2617-2627
Open this publication in new window or tab >>Heat transfer in cold rolling process of AA8015 alloy: a case study of 2-D FE simulation of coupled thermo-mechanical modeling
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2019 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 100, no 9-12, p. 2617-2627Article in journal (Refereed) Published
Abstract [en]

The finite element method (FEM) is one of the most applicable mathematical analytic methods of rolling processes and is also an efficient method for analyzing coupled heat transfer. Thermal analysis of cold rolling process is not frequently used due to the widespread assumption of insignificant impact during rolling process. This research focuses on the development of coupled thermo-mechanical 2-D FE model analysis approach to study the thermal influence and varying coefficient of friction during the industrial cold rolling process of AA8015 aluminum alloy. Both deformable-rigid and deformable-deformable rigid contact algorithms were examined in the 2-D FE model. Findings revealed that temperature distribution in the roll bite rises steadily in a stepwise manner. The deformable-deformable contact algorithm is the best investigations of thermal behavior of the rolled metal and work rolls necessary for typical application in work roll design. The predicted roll separating force is validated with industrial measurements.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
2-D FE model, Contact algorithm, Coupled thermo-mechanical, Heat transfer
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-71692 (URN)10.1007/s00170-018-2811-2 (DOI)000458310400033 ()2-s2.0-85055479036 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-03-08 (johcin)

Available from: 2018-11-21 Created: 2018-11-21 Last updated: 2019-03-08Bibliographically approved
Gyhlesten Back, J. & Lindgren, L.-E. (2019). Influence of prior deformation in austenite on the martensite formation in a low-alloyed carbon steel. Paper presented at 10th International Conference on Processing and Manufacturing of Advanced Materials Processing, Fabrication, Properties, Applications (THERMEC), JUL 09-13, 2018, Paris, FRANCE. Materials Science Forum, 941, 95-99
Open this publication in new window or tab >>Influence of prior deformation in austenite on the martensite formation in a low-alloyed carbon steel
2019 (English)In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 941, p. 95-99Article in journal (Refereed) Published
Abstract [en]

The current work aims at developing models supporting design of the rolling and quenching processes. This requires a martensite formation model that can account for effect of previous plastic deformation as well as evolution of stress and temperature during the quenching step. The effect of deformation prior to the cooling on the transformation is evaluated. The experimental result shows that prior deformation impedes the martensite transformation due to the mechanical stabilisation of the austenite phase. Larger deformation above 30 % reduces the effect of the mechanical stabilisation due to increase in martensite nucleation sites. The computed transformation curves, based on an extended version of the Koistinen-Marburger equation, agree well with experimental results for pre-straining less than 30 %.

Place, publisher, year, edition, pages
Trans Tech Publications, 2019
Keywords
Steel, Martensite, Phase transformation, Modelling, Thermal strain
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-62367 (URN)10.4028/www.scientific.net/MSF.941.95 (DOI)000468152500016 ()
Conference
10th International Conference on Processing and Manufacturing of Advanced Materials Processing, Fabrication, Properties, Applications (THERMEC), JUL 09-13, 2018, Paris, FRANCE
Note

Konferensartikel i tidskrift

Available from: 2017-03-09 Created: 2017-03-09 Last updated: 2019-06-18Bibliographically approved
Draxler, J., Edberg, J., Andersson, J. & Lindgren, L.-E. (2019). Modeling and simulation of weld solidification cracking part I: A pore-based crack criterion. Welding in the World, 63(5), 1489-1502
Open this publication in new window or tab >>Modeling and simulation of weld solidification cracking part I: A pore-based crack criterion
2019 (English)In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 63, no 5, p. 1489-1502Article in journal (Refereed) Published
Abstract [en]

Several advanced alloy systems are susceptible to weld solidification cracking. One example is nickel-based superalloys, which are commonly used in critical applications such as aerospace engines and nuclear power plants. Weld solidification cracking is often expensive to repair and, if not repaired, can lead to catastrophic failure. This study, presented in three papers, presents an approach for simulating weld solidification cracking applicable to large-scale components. The results from finite element simulation of welding are post-processed and combined with models of metallurgy, as well as the behavior of the liquid film between the grain boundaries, in order to estimate the risk of crack initiation. The first paper in this study describes the crack criterion for crack initiation in a grain boundary liquid film. The second paper describes the model for computing the pressure and the thickness of the grain boundary liquid film, which are required to evaluate the crack criterion in paper 1. The third and final paper describes the application of the model to Varestraint tests of alloy 718. The derived model can fairly well predict crack locations, crack orientations, and crack widths for the Varestraint tests. The importance of liquid permeability and strain localization for the predicted crack susceptibility in Varestraint tests is shown.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Solidification cracking, Hot cracking, Varestraint testing, Computational welding mechanics, Alloy 718
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-75660 (URN)10.1007/s40194-019-00760-x (DOI)000482459300029 ()2-s2.0-85068801005 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-22 (johcin)

Available from: 2019-08-22 Created: 2019-08-22 Last updated: 2019-09-13Bibliographically approved
Draxler, J., Edberg, J., Andersson, J. & Lindgren, L.-E. (2019). Modeling and simulation of weld solidification cracking part II: A model for estimation of grain boundary liquid pressure in a columnar dendritic microstructure. Welding in the World, 63(5), 1503-1519
Open this publication in new window or tab >>Modeling and simulation of weld solidification cracking part II: A model for estimation of grain boundary liquid pressure in a columnar dendritic microstructure
2019 (English)In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 63, no 5, p. 1503-1519Article in journal (Refereed) Published
Abstract [en]

Several advanced alloy systems are susceptible to weld solidification cracking. One example is nickel-based superalloys, which are commonly used in critical applications such as aerospace engines and nuclear power plants. Weld solidification cracking is often expensive to repair, and if not repaired, can lead to catastrophic failure. This study, presented in three papers, presents an approach for simulating weld solidification cracking applicable to large-scale components. The results from finite element simulation of welding are post-processed and combined with models of metallurgy, as well as the behavior of the liquid film between the grain boundaries, in order to estimate the risk of crack initiation. The first paper in this study describes the crack criterion for crack initiation in a grain boundary liquid film. The second paper describes the model for computing the pressure and the thickness of the grain boundary liquid film, which are required to evaluate the crack criterion in paper 1. The third and final paper describes the application of the model to Varestraint tests of Alloy 718. The derived model can fairly well predict crack locations, crack orientations, and crack widths for the Varestraint tests. The importance of liquid permeability and strain localization for the predicted crack susceptibility in Varestraint tests is shown.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Solidification cracking, Hot cracking, Varestraint testing, Computational welding mechanics, Alloy 718
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-75653 (URN)10.1007/s40194-019-00761-w (DOI)000482459300030 ()2-s2.0-85068150806 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-22 (johcin)

Available from: 2019-08-22 Created: 2019-08-22 Last updated: 2019-09-13Bibliographically approved
Draxler, J., Edberg, J., Andersson, J. & Lindgren, L.-E. (2019). Modeling and simulation of weld solidification cracking part III: Simulation of solidification cracking in Varestraint tests of alloy 718. Welding in the World
Open this publication in new window or tab >>Modeling and simulation of weld solidification cracking part III: Simulation of solidification cracking in Varestraint tests of alloy 718
2019 (English)In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669Article in journal (Refereed) Epub ahead of print
Abstract [en]

Several advanced alloy systems are susceptible to weld solidification cracking. One example is nickel-based superalloys, which are commonly used in critical applications such as aerospace engines and nuclear power plants. Weld solidification cracking is often expensive to repair, and if not repaired, can lead to catastrophic failure. This study, presented in three papers, presents an approach for simulating weld solidification cracking applicable to large-scale components. The results from finite element simulation of welding are post-processed and combined with models of metallurgy, as well as the behavior of the liquid film between the grain boundaries, in order to estimate the risk of crack initiation. The first paper in this study describes the crack criterion for crack initiation in a grain boundary liquid film. The second paper describes the model required to compute the pressure and thickness of the liquid film required in the crack criterion. The third and final paper describes the application of the model to Varestraint tests of alloy 718. The derived model can fairly well predict crack locations, crack orientations, and crack widths for the Varestraint tests. The importance of liquid permeability and strain localization for the predicted crack susceptibility in Varestraint tests is shown.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Solidification cracking, Hot cracking, Varestraint testing, Computational welding mechanics, Alloy 718
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-76421 (URN)10.1007/s40194-019-00784-3 (DOI)
Available from: 2019-10-17 Created: 2019-10-17 Last updated: 2019-10-17
Lindgren, L.-E., Edberg, J., Åkerström, P. & Zhang, Z. (2019). Modeling of thermal stresses in low alloy steels. Paper presented at The 12th International Congress on Thermal Stresses June 1–5, 2019, Zhejiang University, Hangzhou, China. Journal of thermal stresses, 42(6), 725-743
Open this publication in new window or tab >>Modeling of thermal stresses in low alloy steels
2019 (English)In: Journal of thermal stresses, ISSN 0149-5739, E-ISSN 1521-074X, Vol. 42, no 6, p. 725-743Article in journal (Refereed) Published
Abstract [en]

Computing the evolution of thermal stresses accurately requires appropriate constitutive relations. This includes both the thermal and mechanical aspects, as temperature is the driver to thermal stresses. The paradigm of Integrated Computational Materials Engineering (ICME) aims at being able to quantitatively relate process-structure-property of a material. The article describes physics based models, denoted bridging elements, which are one step towards the vision of ICME. They couple material structure with heat capacity, heat conductivity, thermal and transformation strains and elastic properties for hypo-eutectoid steels. The models can account for the chemical composition of the steel and its processing, i.e. thermomechanical history, giving the evolution of the microstructure and the corresponding properties.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
Elastic properties, heat capacity, heat conductivity, thermal expansion, thermal stresses
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-73488 (URN)10.1080/01495739.2019.1587329 (DOI)000468282400003 ()2-s2.0-85063905757 (Scopus ID)
Conference
The 12th International Congress on Thermal Stresses June 1–5, 2019, Zhejiang University, Hangzhou, China
Note

Konferensartikel i tidskrift

Available from: 2019-04-08 Created: 2019-04-08 Last updated: 2019-09-13Bibliographically approved
Lindgren, L.-E., Lundbäck, A., Fisk, M. & Draxler, J. (2019). Modelling additive manufacturing of superalloys. Paper presented at The 2nd International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2019, 8-10 March 2019, Sun City, South Africa. Procedia Manufacturing, 35, 252-258
Open this publication in new window or tab >>Modelling additive manufacturing of superalloys
2019 (English)In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 35, p. 252-258Article in journal (Refereed) Published
Abstract [en]

There exist several variants of Additive Manufacturing (AM) applicable for metals and alloys. The two main groups are Directed Energy Deposition (DED) and Powder Bed Fusion (PBF). AM has advantages and disadvantages when compared to more traditional manufacturing methods. The best candidate products are those with complex shape and small series and particularly individualized product. Repair welding is often individualized as defects may occur at various instances in a component. This method was used before it became categorized as AM and in most cases, it is a DED process. PBF processes are more useful for smaller items and can give a finer surface. Both DED and PBF products require subsequent surface finishing for high performance components and sometimes there is also a need for post heat treatment. Modelling of AM as well as eventual post-processes can be of use in order to improve product quality, reducing costs and material waste. The paper describes the use of the finite element method to simulate these processes with focus on superalloys.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Additive manufacturing, Simulation, Superalloys, Quality
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-75726 (URN)10.1016/j.promfg.2019.05.036 (DOI)
Conference
The 2nd International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2019, 8-10 March 2019, Sun City, South Africa
Note

Konferensartikel i tidskrift

Available from: 2019-08-28 Created: 2019-08-28 Last updated: 2019-08-28Bibliographically approved
Draxler, J., Edberg, J., Andersson, J. & Lindgren, L.-E. (2019). Simulation of weld solidifiation cracking in varestraint tests of alloy 718. In: C. Sommitsch (Ed.), : . Paper presented at Mathematical Modelling of Weld Phenomena (pp. 485-504). Gratz, 12
Open this publication in new window or tab >>Simulation of weld solidifiation cracking in varestraint tests of alloy 718
2019 (English)In: / [ed] C. Sommitsch, Gratz, 2019, Vol. 12, p. 485-504Conference paper, Published paper (Refereed)
Abstract [en]

Several nickel-based superalloys are susceptible to weld solidification cracking. Numerical simulation can be a powerful tool for optimizing the welding process such that solidification cracking can be avoided. In order to simulate the cracking, a crack model inspired by the RDG model is proposed. The model is based on a crack criterion that estimates the likelihood for a preexisting pore in a grain boundary liquid film to form a crack. The criterion depends on the thickness and the liquid pressure in the grain boundary liquid film, as well as the surface tension of the pore. The thickness of the liquid film is computed from the macroscopic mechanical strain field of an FE model with a double ellipsoidal heat source. A temperature-dependent length scale is used to partition the macroscopic strain to the liquid film. The liquid pressure in the film is evaluated using a combination of Poiseuille parallel plate flow and Darcy’s law for porous flows. The Poiseuille flow is used for the part of the grain boundary liquid film that extends into the region with liquid fraction less than 0.1, while Darcy’s law is used for the rest of the liquid film that extends into the regions with liquid fraction greater than 0.1. The proposed model was calibrated and evaluated in Varestraint tests of Alloy 718. Crack location, width, and orientation were all accurately predicted by the model.

Place, publisher, year, edition, pages
Gratz: , 2019
Series
Mathematical Modelling of Weld Phenomena, ISSN 2410-0544 ; 12
Keywords
Solidification cracking, Hot cracking, Varestraint testing, Computational Welding Mechanics, Alloy 718
National Category
Manufacturing, Surface and Joining Technology
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-75740 (URN)10.3217/978-3-85125-615-4-26 (DOI)978-3-85125-615-4 (ISBN)
Conference
Mathematical Modelling of Weld Phenomena
Available from: 2019-08-29 Created: 2019-08-29 Last updated: 2019-10-17
Lindwall, J., Pacheco, V., Sahlberg, M., Lundbäck, A. & Lindgren, L.-E. (2019). Thermal simulation and phase modeling of bulk metallic glass in the powder bed fusion process. Additive Manufacturing, 27, 345-352
Open this publication in new window or tab >>Thermal simulation and phase modeling of bulk metallic glass in the powder bed fusion process
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2019 (English)In: Additive Manufacturing, ISSN 2214-8604, Vol. 27, p. 345-352Article in journal (Refereed) Published
Abstract [en]

One of the major challenges with the powder bed fusion process (PBF) and formation of bulk metallic glass (BMG) is the development of process parameters for a stable process and a defect-free component. The focus of this study is to predict formation of a crystalline phase in the glass forming alloy AMZ4 during PBF. The approach combines a thermal finite element model for prediction of the temperature field and a phase model for prediction of crystallization and devitrification. The challenge to simulate the complexity of the heat source has been addressed by utilizing temporal reduction in a layer-by-layer fashion by a simplified heat source model. The heat source model considers the laser power, penetration depth and hatch spacing and is represented by a volumetric heat density equation in one dimension. The phase model is developed and calibrated to DSC measurements at varying heating rates. It can predict the formation of crystalline phase during the non-isothermal process. Results indicate that a critical location for devitrification is located a few layers beneath the top surface. The peak is four layers down where the crystalline volume fraction reaches 4.8% when 50 layers are built.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Additive manufacturing simulation, BMG, Heat input modeling, PBF, Phase evolution
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-73489 (URN)10.1016/j.addma.2019.03.011 (DOI)000466995800034 ()
Note

Validerad;2019;Nivå 2;2019-04-08 (svasva)

Available from: 2019-04-08 Created: 2019-04-08 Last updated: 2019-06-24Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-2544-9168

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