Ultra-Fine Grained Dual-Phase Steels
This paper provides an overview on obtaining low-carbon ultra-fine grained dual-phase steels through rapid intercritical annealing of cold-rolled sheet as improved materials for automotive applications. A laboratory processing route was designed that involves cold-rolling of a tempered martensite st...
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| Format: | Article |
| Language: | English |
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University of Tehran
2012-10-01
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| Series: | Journal of Ultrafine Grained and Nanostructured Materials |
| Subjects: | |
| Online Access: | http://jufgnsm.ut.ac.ir/article_29313_23004a176ae0b2f2a67bff778632887a.pdf |
| _version_ | 1818248726513188864 |
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| author | Matthias Militzer Hamid Azizi-Alizamini Vishnu Charan Sangem |
| author_facet | Matthias Militzer Hamid Azizi-Alizamini Vishnu Charan Sangem |
| author_sort | Matthias Militzer |
| collection | DOAJ |
| description | This paper provides an overview on obtaining low-carbon ultra-fine grained dual-phase steels through rapid intercritical annealing of cold-rolled sheet as improved materials for automotive applications. A laboratory processing route was designed that involves cold-rolling of a tempered martensite structure followed by a second tempering step to produce a fine grained aggregate of ferrite and carbides as the initial microstructure for rapid intercritical annealing. The intercritical annealing step was performed with heating and cooling rates of at least 100 °C/s and a holding time of 30 s. The intercritical temperature was selected to result in 20- 35% martensite in the final microstructures for C-Mn steels with carbon contents of 0.06, 0.12 and 0.17 wt%, respectively. The proposed processing routes produced an ultra-fine grained ferrite-martensite structure withgrain sizes of approximately 1 ?m for all three steels. The tensile strength of these ultra-fine grained dualphase steels can be increased by up to 200 MPa as compared to coarse-grained dual-phase steels while maintaining uniform elongation values. The rather narrow processing window necessary to obtain these properties was evaluated by determining the effect of intercritical annealing conditions on microstructure evolution. Further, the experimental results were confirmed with phase field simulations of austenite formation indicating that rapid heat treatment cycles are essential to obtain fine grained intercritical austenite that leads to martensite islands with sizes of 1 ?m and below in the final microstructure. |
| first_indexed | 2024-12-12T15:25:11Z |
| format | Article |
| id | doaj.art-1dc49ef1f9fb40c6969604a26b770d24 |
| institution | Directory Open Access Journal |
| issn | 2423-6845 2423-6837 |
| language | English |
| last_indexed | 2024-12-12T15:25:11Z |
| publishDate | 2012-10-01 |
| publisher | University of Tehran |
| record_format | Article |
| series | Journal of Ultrafine Grained and Nanostructured Materials |
| spelling | doaj.art-1dc49ef1f9fb40c6969604a26b770d242022-12-22T00:20:15ZengUniversity of TehranJournal of Ultrafine Grained and Nanostructured Materials2423-68452423-68372012-10-014511610.7508/jufgnsm.2012.01.00129313Ultra-Fine Grained Dual-Phase SteelsMatthias Militzer0Hamid Azizi-Alizamini1Vishnu Charan Sangem2The Centre for Metallurgical Process Engineering, The University of British ColumbiaThe Centre for Metallurgical Process Engineering, The University of British ColumbiaThe Centre for Metallurgical Process Engineering, The University of British ColumbiaThis paper provides an overview on obtaining low-carbon ultra-fine grained dual-phase steels through rapid intercritical annealing of cold-rolled sheet as improved materials for automotive applications. A laboratory processing route was designed that involves cold-rolling of a tempered martensite structure followed by a second tempering step to produce a fine grained aggregate of ferrite and carbides as the initial microstructure for rapid intercritical annealing. The intercritical annealing step was performed with heating and cooling rates of at least 100 °C/s and a holding time of 30 s. The intercritical temperature was selected to result in 20- 35% martensite in the final microstructures for C-Mn steels with carbon contents of 0.06, 0.12 and 0.17 wt%, respectively. The proposed processing routes produced an ultra-fine grained ferrite-martensite structure withgrain sizes of approximately 1 ?m for all three steels. The tensile strength of these ultra-fine grained dualphase steels can be increased by up to 200 MPa as compared to coarse-grained dual-phase steels while maintaining uniform elongation values. The rather narrow processing window necessary to obtain these properties was evaluated by determining the effect of intercritical annealing conditions on microstructure evolution. Further, the experimental results were confirmed with phase field simulations of austenite formation indicating that rapid heat treatment cycles are essential to obtain fine grained intercritical austenite that leads to martensite islands with sizes of 1 ?m and below in the final microstructure.http://jufgnsm.ut.ac.ir/article_29313_23004a176ae0b2f2a67bff778632887a.pdfGrain RefinementIntercritical annealingLow-carbon steelsmechanical propertiesPhase field modelling |
| spellingShingle | Matthias Militzer Hamid Azizi-Alizamini Vishnu Charan Sangem Ultra-Fine Grained Dual-Phase Steels Journal of Ultrafine Grained and Nanostructured Materials Grain Refinement Intercritical annealing Low-carbon steels mechanical properties Phase field modelling |
| title | Ultra-Fine Grained Dual-Phase Steels |
| title_full | Ultra-Fine Grained Dual-Phase Steels |
| title_fullStr | Ultra-Fine Grained Dual-Phase Steels |
| title_full_unstemmed | Ultra-Fine Grained Dual-Phase Steels |
| title_short | Ultra-Fine Grained Dual-Phase Steels |
| title_sort | ultra fine grained dual phase steels |
| topic | Grain Refinement Intercritical annealing Low-carbon steels mechanical properties Phase field modelling |
| url | http://jufgnsm.ut.ac.ir/article_29313_23004a176ae0b2f2a67bff778632887a.pdf |
| work_keys_str_mv | AT matthiasmilitzer ultrafinegraineddualphasesteels AT hamidazizializamini ultrafinegraineddualphasesteels AT vishnucharansangem ultrafinegraineddualphasesteels |