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Calmunger, Mattias
Publications (10 of 39) Show all publications
Azeez, A., Eriksson, R., Leidermark, D. & Calmunger, M. (2020). Low cycle fatigue life modelling using finite element strain range partitioning for a steam turbine rotor steel. Theoretical and applied fracture mechanics (Print), 107
Open this publication in new window or tab >>Low cycle fatigue life modelling using finite element strain range partitioning for a steam turbine rotor steel
2020 (English)In: Theoretical and applied fracture mechanics (Print), ISSN 0167-8442, E-ISSN 1872-7638, Vol. 107Article in journal (Refereed) Epub ahead of print
Abstract [en]

Materials made for modern steam power plants are required to withstand high temperatures and flexible operational schedule. Mainly to achieve high efficiency and longer components life. Nevertheless, materials under such conditions experience crack initiations and propagations. Thus, life prediction must be made using accurate fatigue models to allow flexible operation. In this study, fully reversed isothermal low cycle fatigue tests were performed on a turbine rotor steel called FB2. The tests were done under strain control with different total strain ranges and temperatures (20 °C to 625 °C). Some tests included dwell time to calibrate the short-time creep behaviour of the material. Different fatigue life models were evaluated based on total life approach. The stress-based fatigue life model was found unusable at 600 °C, while the strain-based models in terms of total strain or inelastic strain amplitudes displayed inconsistent behaviour at 500 °C. To construct better life prediction, the inelastic strain amplitudes were separated into plastic and creep components by modelling the deformation behaviour of the material, including creep. Based on strain range partitioning approach, the fatigue life depends on different damage mechanisms at different strain ranges at 500 °C. This allows for the formulation of life curves based on either plasticity-dominated damage or creep-dominated damage. At 600 °C, creep dominated while at 500 °C creep only dominates for higher strain ranges. The deformation mechanisms at different temperatures and total strain ranges were characterised by scanning electron microscopy and by quantifying the amount of low angle grain boundaries. The quantification of low angle grain boundaries was done by electron backscatter diffraction. Microscopy revealed that specimens subjected to 600 °C showed signs of creep damage in the form of voids close to the fracture surface. In addition, the amount of low angle grain boundaries seems to decrease with the increase in temperature even though the inelastic strain amplitude was increased. The study indicates that a significant amount of the inelastic strain comes from creep strain as opposed of being all plastic strain, which need to be taken into consideration when constructing a life prediction model.

Keywords
Creep-fatigue interaction, Creep-resistant steel, EBSD, Low cycle fatigue, Steam turbine steel, Strain range partitioning
National Category
Applied Mechanics
Identifiers
urn:nbn:se:liu:diva-164610 (URN)10.1016/j.tafmec.2020.102510 (DOI)
Available from: 2020-03-26 Created: 2020-03-26 Last updated: 2020-03-26
Azeez, A., Eriksson, R. & Calmunger, M. (2019). Characterisation of Deformation and Damage in a Steam Turbine Steel Subjected to Low Cycle Fatigue. In: Elsevier (Ed.), Structural Integrity Procedia: . Paper presented at 9th International Conference on Materials Structure and Micromechanics of Fracture, MSMF9, Brno, Czech Republic, June 26-28, 2019. (pp. 155-160). , 23
Open this publication in new window or tab >>Characterisation of Deformation and Damage in a Steam Turbine Steel Subjected to Low Cycle Fatigue
2019 (English)In: Structural Integrity Procedia / [ed] Elsevier, 2019, Vol. 23, p. 155-160Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

The increased use of renewable energy pushes steam turbines toward a more frequent operation schedule. Consequently, components must endure more severe fatigue loads which, in turn, requires an understanding of the deformation and damage mechanisms under high-temperature cyclic loading. Based on this, low cycle fatigue tests were performed on a creep resistant steel, FB2, used in ultra-supercritical steam turbines. The fatigue tests were performed in strain control with 0.8-1.2 % strain range and at temperatures of 400 °C and 600 °C. The tests at 600 °C were run with and without dwell time. The deformation mechanisms at different temperatures and strain ranges were characterised by scanning electron microscopy and by quantifying the amount of low angle grain boundaries. The quantification of low angle grain boundaries was done by electron backscatter diffraction. Microscopy revealed that specimens subjected to 600 °C showed signs of creep damage, in the form of voids close to fracture surface, regardless of whether the specimen had been exposed to dwell time or been purely cycled. In addition, the amount of low angle grain boundaries was lower at 600 °C than at 400 °C. The study indicates that a significant amount of the inelastic strain comes from creep strain as opposed to being all plastic strain.

Series
Procedia Structural Integrity, ISSN 2452-3216
Keywords
Low cycle fatigue, Steam turbine steel, FB2, EBSD, Creep-fatigue interaction
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-161725 (URN)10.1016/j.prostr.2020.01.079 (DOI)
Conference
9th International Conference on Materials Structure and Micromechanics of Fracture, MSMF9, Brno, Czech Republic, June 26-28, 2019.
Available from: 2019-11-07 Created: 2019-11-07 Last updated: 2020-03-02Bibliographically approved
Calmunger, M., Eriksson, R., Lindström, T. & Leidermark, D. (2019). Effect of Additive Manufacturing on Fatigue Crack Propagation of a Gas Turbine Superalloy. In: Structural Integrity Procedia: . Paper presented at 9th International Conference on Materials Structure and Micromechanics of Fracture, MSMF9, Brno, Czech Republic, June 26-28, 2019.. Elsevier
Open this publication in new window or tab >>Effect of Additive Manufacturing on Fatigue Crack Propagation of a Gas Turbine Superalloy
2019 (English)In: Structural Integrity Procedia, Elsevier, 2019Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Additive manufacturing, fatigue fractography, EBSD
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-161724 (URN)
Conference
9th International Conference on Materials Structure and Micromechanics of Fracture, MSMF9, Brno, Czech Republic, June 26-28, 2019.
Available from: 2019-11-07 Created: 2019-11-07 Last updated: 2019-11-15Bibliographically approved
Calmunger, M., Wärner, H., Chai, G., Johansson, S. & Moverare, J. (2019). High Temperature Properties of Austenitic Stainless Steels for Future Power Plant Applications. In: : . Paper presented at EUROMAT19, Stockholm 2-5 September 2019.
Open this publication in new window or tab >>High Temperature Properties of Austenitic Stainless Steels for Future Power Plant Applications
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2019 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-162815 (URN)
Conference
EUROMAT19, Stockholm 2-5 September 2019
Available from: 2019-12-19 Created: 2019-12-19 Last updated: 2019-12-19
Wärner, H., Eriksson, R., Chai, G., Moverare, J., Johansson, S. & Calmunger, M. (2019). Influence of Ageing on Thermomechaical Fatigue of Austenitic Stainless Steels. In: Elsevier (Ed.), Structural Integrity Procedia: . Paper presented at 9th International Conference on Materials Structures and Micromechanics of Fracture, MSMF9, in Brno, Czech Republic, June 26-28, 2019. Elsevier
Open this publication in new window or tab >>Influence of Ageing on Thermomechaical Fatigue of Austenitic Stainless Steels
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2019 (English)In: Structural Integrity Procedia / [ed] Elsevier, Elsevier, 2019Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Thermomechanical fatigue, Austenitic stainless steels, Ageing, Barrelling effect
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-161737 (URN)
Conference
9th International Conference on Materials Structures and Micromechanics of Fracture, MSMF9, in Brno, Czech Republic, June 26-28, 2019
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2019-11-12
Bergwall, M., Hederberg, H., Calmunger, M., Murtagh, T., Rinn, F. & Loukil, M. S. (2019). Innovative Out-of-Autoclave Composite Manufacturing Method for Saving Cost. In: : . Paper presented at EUROMAT19, Stockholm, 2-5 September 2019.
Open this publication in new window or tab >>Innovative Out-of-Autoclave Composite Manufacturing Method for Saving Cost
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2019 (English)Conference paper, Oral presentation only (Refereed)
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-162818 (URN)
Conference
EUROMAT19, Stockholm, 2-5 September 2019
Available from: 2019-12-19 Created: 2019-12-19 Last updated: 2020-02-06
Azeez, A., Eriksson, R., Calmunger, M., Lindström, S. B. & Simonsson, K. (2019). Low Cycle Fatigue Modelling of Steam Turbine Rotor Steel. In: Elsevier (Ed.), Structural Integrity Procedia: . Paper presented at 9th International Conference on Materials Structures and Micromechanics of Fracture, MSMF9, in Brno, Czech Republic, June 26-28, 2019 (pp. 149-154). Elsevier, 23
Open this publication in new window or tab >>Low Cycle Fatigue Modelling of Steam Turbine Rotor Steel
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2019 (English)In: Structural Integrity Procedia / [ed] Elsevier, Elsevier, 2019, Vol. 23, p. 149-154Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Materials in steam turbine rotors are subjected to cyclic loads at high temperature, causing cracks to initiate and grow. To allow for more flexible operation, accurate fatigue models for life prediction must not be overly conservative. In this study, fully reversed low cycle fatigue tests were performed on a turbine rotor steel called FB2. The tests were done isothermally, within temperature range of room temperature to 600 °C, under strain control with 0.8-1.2 % total strain range. Some tests included hold time to calibrate the short-time creep behaviour of the material. Different fatigue life models were constructed. The life curve in terms of stress amplitude was found unusable at 600 °C, while the life curve in terms of total strain or inelastic strain amplitudes displayed inconsistent behaviour at 500 °C. To construct better life model, the inelastic strain amplitudes were separated into plastic and creep components by modelling the deformation behaviour of the material, including creep. Based on strain range partitioning approach, the fatigue life depends on different damage mechanisms at different strain ranges. This allowed the formulation of life curves based on plasticity or creep domination, which showed creep domination at 600 °C, while at 500 °C, creep only dominates for higher strain range.

Place, publisher, year, edition, pages
Elsevier, 2019
Series
Procedia Structural Integrity, ISSN 2452-3216
Keywords
Low cycle fatigue, Creep-fatigue intraction, Strain range partitioning, FB2, Creep-resistant steel, Rotor steel
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-161736 (URN)10.1016/j.prostr.2020.01.078 (DOI)
Conference
9th International Conference on Materials Structures and Micromechanics of Fracture, MSMF9, in Brno, Czech Republic, June 26-28, 2019
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2020-03-02Bibliographically approved
Wärner, H., Calmunger, M., Chai, G. & Moverare, J. (2019). Microscopic Evaluation of Creep-Fatigue Interaction in Heat Resistant Austenic Alloys. In: : . Paper presented at EUROMAT19, Stockholm 2-5 September 2019.
Open this publication in new window or tab >>Microscopic Evaluation of Creep-Fatigue Interaction in Heat Resistant Austenic Alloys
2019 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-162817 (URN)
Conference
EUROMAT19, Stockholm 2-5 September 2019
Available from: 2019-12-19 Created: 2019-12-19 Last updated: 2019-12-19
Wärner, H., Calmunger, M., Chai, G., Johansson, S. & Moverare, J. (2019). Structural Integrity and Impact Toughness of Austenitic Stainless Steels. In: Proceedings of the 13th International Conference on the Mechanical Behaviour of Materials: . Paper presented at 13th International Conference on the Mechanical Behaviour of Materials (ICM13), 11-14 June 2019, Melbourne, Australia.
Open this publication in new window or tab >>Structural Integrity and Impact Toughness of Austenitic Stainless Steels
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2019 (English)In: Proceedings of the 13th International Conference on the Mechanical Behaviour of Materials, 2019Conference paper, Published paper (Refereed)
Keywords
Austenitic stainless steels, long-term ageing, impact toughness, fracture mechanisms
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-162679 (URN)978-1-922016-65-2 (ISBN)
Conference
13th International Conference on the Mechanical Behaviour of Materials (ICM13), 11-14 June 2019, Melbourne, Australia
Available from: 2019-12-16 Created: 2019-12-16 Last updated: 2019-12-16
Wärner, H., Calmunger, M., Chai, G., Johansson, S. & Moverare, J. (2019). Thermomechanical Fatigue Behaviour of Aged Heat Resistant Austenitic Alloys. International Journal of Fatigue (127), 509-521
Open this publication in new window or tab >>Thermomechanical Fatigue Behaviour of Aged Heat Resistant Austenitic Alloys
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2019 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, no 127, p. 509-521Article in journal (Refereed) Published
Abstract [en]

The increasing demands for efficiency and flexibility result in more severe operating conditions for the materials used in critical components of biomass power plants. These operating conditions involve higher temperature ranges, more pronounced environmental effects and cyclic operations. Austenitic stainless steels have shown to possess promising high temperature properties which makes them suitable as candidates for critical components in biomass power plant. However, their behaviour under such conditions is not yet fully understood. This work investigates three commercial austenitic alloys: Esshete 1250, Sanicro 25 and Sanicro 31HT. The alloys were subjected to in-phase (IP) thermomechanical fatigue (TMF) testing under strain-control in the temperature range of 100–800 °C. Both virgin and pre-aged TMF specimens were tested in order to simulate service degradation resulting from long-term usage. The results show that the pre-aged specimens suffered shorter TMF-life compared to the virgin specimens. The scanning electron microscopy methods electron backscatter diffraction (EBSD) and energy dispersive spectroscopy (EDS) were used to analyse and discuss active failure and deformation mechanisms. The difference in TMF-life produced by the two testing conditions was attributed to an embrittling effect by precipitation, reduced creep properties and oxidation assisted cracking.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Thermomechanical fatigue, austenitic alloys, pre-ageing
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-159644 (URN)10.1016/j.ijfatigue.2019.06.012 (DOI)000482492600046 ()2-s2.0-85068255817 (Scopus ID)
Note

Funding agencies: AB Sandvik Materials Technology in Sweden; Swedish Energy Agency through the Research Consortium of Materials Technology for Thermal Energy Processes [KME-701]

Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-10-16Bibliographically approved
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