Effect of Annealing Prior to Cold Rolling on the Microstructure Evolution and Energy Losses of Low-Si, Ultra-Low-C Hot-Rolled Electrical Steel
The microstructure of a low Si, ultra-low-C, hot-rolled electrical steel strip is modified by annealing at T < To, the α→γ transformation temperature. This heat treatment causes the abnormal anisotropic growth of surface grains which consumes the original hot-rolled microstructure. The growth of...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2020-07-01
|
| Series: | Metals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4701/10/7/957 |
| _version_ | 1797562350889336832 |
|---|---|
| author | Héctor Ortiz Rangel Armando Salinas Rodríguez Omar García Rincón |
| author_facet | Héctor Ortiz Rangel Armando Salinas Rodríguez Omar García Rincón |
| author_sort | Héctor Ortiz Rangel |
| collection | DOAJ |
| description | The microstructure of a low Si, ultra-low-C, hot-rolled electrical steel strip is modified by annealing at T < To, the α→γ transformation temperature. This heat treatment causes the abnormal anisotropic growth of surface grains which consumes the original hot-rolled microstructure. The growth of the surface grains first takes place parallel to the rolling direction and then in a columnar form parallel to the normal direction until grains growing in opposite directions from the surfaces impinge at the center of the strip. It is shown that cold rolling and a short annealing treatment at temperatures between 700 and 800 °C leads to microstructures which result in iron energy losses that can be as much as 30% lower than those observed in the same material not subjected to the annealing prior to cold rolling. The magnitude of the reduction in energy losses depends on strip thickness and processing parameters. The major effect is observed in material annealed at 710 °C and the relative effect (with respect to material that is not annealed prior to cold rolling) decreases as the strip thickness decreases. It is shown that these effects can be attributed to the effect of the processing conditions on texture and grain size. The maximum reduction in energy losses is observed when the final microstructure consists of ferrite grains ~1.5 times larger than those obtained if the material is not annealed prior to cold rolling. |
| first_indexed | 2024-03-10T18:27:58Z |
| format | Article |
| id | doaj.art-c0666c7ac1454dc7a7fe2ec8cd4321cf |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T18:27:58Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-c0666c7ac1454dc7a7fe2ec8cd4321cf2023-11-20T06:54:16ZengMDPI AGMetals2075-47012020-07-0110795710.3390/met10070957Effect of Annealing Prior to Cold Rolling on the Microstructure Evolution and Energy Losses of Low-Si, Ultra-Low-C Hot-Rolled Electrical SteelHéctor Ortiz Rangel0Armando Salinas Rodríguez1Omar García Rincón2Department of Metallurgical Engineering and Materials Science, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV Saltillo), Ramos Arizpe 25900, Coahuila, MexicoDepartment of Metallurgical Engineering and Materials Science, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV Saltillo), Ramos Arizpe 25900, Coahuila, MexicoDepatment of Enginnering and Development, Ternium México S.A. de C.V, Monterrey 66450, MexicoThe microstructure of a low Si, ultra-low-C, hot-rolled electrical steel strip is modified by annealing at T < To, the α→γ transformation temperature. This heat treatment causes the abnormal anisotropic growth of surface grains which consumes the original hot-rolled microstructure. The growth of the surface grains first takes place parallel to the rolling direction and then in a columnar form parallel to the normal direction until grains growing in opposite directions from the surfaces impinge at the center of the strip. It is shown that cold rolling and a short annealing treatment at temperatures between 700 and 800 °C leads to microstructures which result in iron energy losses that can be as much as 30% lower than those observed in the same material not subjected to the annealing prior to cold rolling. The magnitude of the reduction in energy losses depends on strip thickness and processing parameters. The major effect is observed in material annealed at 710 °C and the relative effect (with respect to material that is not annealed prior to cold rolling) decreases as the strip thickness decreases. It is shown that these effects can be attributed to the effect of the processing conditions on texture and grain size. The maximum reduction in energy losses is observed when the final microstructure consists of ferrite grains ~1.5 times larger than those obtained if the material is not annealed prior to cold rolling.https://www.mdpi.com/2075-4701/10/7/957ultra-low-Ccore lossgrain non-orientedabnormal growth |
| spellingShingle | Héctor Ortiz Rangel Armando Salinas Rodríguez Omar García Rincón Effect of Annealing Prior to Cold Rolling on the Microstructure Evolution and Energy Losses of Low-Si, Ultra-Low-C Hot-Rolled Electrical Steel Metals ultra-low-C core loss grain non-oriented abnormal growth |
| title | Effect of Annealing Prior to Cold Rolling on the Microstructure Evolution and Energy Losses of Low-Si, Ultra-Low-C Hot-Rolled Electrical Steel |
| title_full | Effect of Annealing Prior to Cold Rolling on the Microstructure Evolution and Energy Losses of Low-Si, Ultra-Low-C Hot-Rolled Electrical Steel |
| title_fullStr | Effect of Annealing Prior to Cold Rolling on the Microstructure Evolution and Energy Losses of Low-Si, Ultra-Low-C Hot-Rolled Electrical Steel |
| title_full_unstemmed | Effect of Annealing Prior to Cold Rolling on the Microstructure Evolution and Energy Losses of Low-Si, Ultra-Low-C Hot-Rolled Electrical Steel |
| title_short | Effect of Annealing Prior to Cold Rolling on the Microstructure Evolution and Energy Losses of Low-Si, Ultra-Low-C Hot-Rolled Electrical Steel |
| title_sort | effect of annealing prior to cold rolling on the microstructure evolution and energy losses of low si ultra low c hot rolled electrical steel |
| topic | ultra-low-C core loss grain non-oriented abnormal growth |
| url | https://www.mdpi.com/2075-4701/10/7/957 |
| work_keys_str_mv | AT hectorortizrangel effectofannealingpriortocoldrollingonthemicrostructureevolutionandenergylossesoflowsiultralowchotrolledelectricalsteel AT armandosalinasrodriguez effectofannealingpriortocoldrollingonthemicrostructureevolutionandenergylossesoflowsiultralowchotrolledelectricalsteel AT omargarciarincon effectofannealingpriortocoldrollingonthemicrostructureevolutionandenergylossesoflowsiultralowchotrolledelectricalsteel |