Details
| Original language | English |
|---|---|
| Title of host publication | 9th International Conference on Hot Sheet Metal Forming of High-Performance Steel |
| Subtitle of host publication | CHS2 2024 - Proceedings |
| Editors | Daniel Casellas, Jens Hardell |
| Pages | 126-132 |
| Number of pages | 7 |
| ISBN (electronic) | 9780930767303 |
| Publication status | Published - 27 May 2024 |
| Event | 9th International Conference on Hot Sheet Metal Forming of High-Performance Steel, CHS2 2024 - Nashville, United States Duration: 27 May 2024 → 29 May 2024 |
Abstract
Hot stamping is used to produce ultra-high-strength components that are used in the automotive industry. Typical applications can be found in the bumper area or in the A and B pillars. In the hot stamping process, a manganese-boron steel is first heated above the austenitisation temperature, usually 950 °C, and then formed and hardened in a water-cooled tool. At cooling rates of more than 27 K/s, a fully martensitic microstructure is established, whereby tensile strengths of more than 1500 MPa can be achieved. The sheets are usually heated in a roller hearth furnace for 8 to 10 minutes so that the aluminium silicon (AlSi) coating forms a sufficient intermetallic phase to prevent the sheet from scaling during heating. Since the heating of the sheets must be coordinated with the cycle time of the press, these roller hearth furnaces are up to 60 m long. Conductive heating provides an alternative here. Due to the very fast heating times of > 100 K/s, sheets can be heated up to 950 °C in less than 10 s in a space-saving manner. Due to the direct current flow through the sheet, 68 % of the energy can be saved compared to roller hearth furnaces. The heating time of 10 s is not sufficient for the common coatings to form a good bond with the sheet material. A new approach is conductive heating in an XHV-adequate atmosphere. The process gases nitrogen and silane reduce the oxygen content in the heating chamber to an XHV-adequate level, which means that uncoated sheets can also be heated without scale. By integrating coating nozzles into the heating chamber, the XHV (extremely high vacuum)-adequate environment and the heating energy can be used to coat the sheets. Within the scope of this research coatings adapted to the rapid heating are developed and tested for the forming temperatures by means of an integrated stretching device inside the chamber.
ASJC Scopus subject areas
- Engineering(all)
- Mechanical Engineering
- Engineering(all)
- Mechanics of Materials
- Materials Science(all)
- Metals and Alloys
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
9th International Conference on Hot Sheet Metal Forming of High-Performance Steel: CHS2 2024 - Proceedings. ed. / Daniel Casellas; Jens Hardell. 2024. p. 126-132.
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Resistance Heating in XHV-Adequate Atmosphere
T2 - 9th International Conference on Hot Sheet Metal Forming of High-Performance Steel, CHS2 2024
AU - Behrens, Bernd Arno
AU - Hübner, Sven
AU - Holländer, Ulrich
AU - Langohr, André
AU - Wehmeyer, Jörn
AU - Fünfkirchler, Timo
AU - Kahrizi, Ehsan Farahmand
AU - Albracht, Lorenz
N1 - Publisher Copyright: © CHS2 2024 . All rights reserved.
PY - 2024/5/27
Y1 - 2024/5/27
N2 - Hot stamping is used to produce ultra-high-strength components that are used in the automotive industry. Typical applications can be found in the bumper area or in the A and B pillars. In the hot stamping process, a manganese-boron steel is first heated above the austenitisation temperature, usually 950 °C, and then formed and hardened in a water-cooled tool. At cooling rates of more than 27 K/s, a fully martensitic microstructure is established, whereby tensile strengths of more than 1500 MPa can be achieved. The sheets are usually heated in a roller hearth furnace for 8 to 10 minutes so that the aluminium silicon (AlSi) coating forms a sufficient intermetallic phase to prevent the sheet from scaling during heating. Since the heating of the sheets must be coordinated with the cycle time of the press, these roller hearth furnaces are up to 60 m long. Conductive heating provides an alternative here. Due to the very fast heating times of > 100 K/s, sheets can be heated up to 950 °C in less than 10 s in a space-saving manner. Due to the direct current flow through the sheet, 68 % of the energy can be saved compared to roller hearth furnaces. The heating time of 10 s is not sufficient for the common coatings to form a good bond with the sheet material. A new approach is conductive heating in an XHV-adequate atmosphere. The process gases nitrogen and silane reduce the oxygen content in the heating chamber to an XHV-adequate level, which means that uncoated sheets can also be heated without scale. By integrating coating nozzles into the heating chamber, the XHV (extremely high vacuum)-adequate environment and the heating energy can be used to coat the sheets. Within the scope of this research coatings adapted to the rapid heating are developed and tested for the forming temperatures by means of an integrated stretching device inside the chamber.
AB - Hot stamping is used to produce ultra-high-strength components that are used in the automotive industry. Typical applications can be found in the bumper area or in the A and B pillars. In the hot stamping process, a manganese-boron steel is first heated above the austenitisation temperature, usually 950 °C, and then formed and hardened in a water-cooled tool. At cooling rates of more than 27 K/s, a fully martensitic microstructure is established, whereby tensile strengths of more than 1500 MPa can be achieved. The sheets are usually heated in a roller hearth furnace for 8 to 10 minutes so that the aluminium silicon (AlSi) coating forms a sufficient intermetallic phase to prevent the sheet from scaling during heating. Since the heating of the sheets must be coordinated with the cycle time of the press, these roller hearth furnaces are up to 60 m long. Conductive heating provides an alternative here. Due to the very fast heating times of > 100 K/s, sheets can be heated up to 950 °C in less than 10 s in a space-saving manner. Due to the direct current flow through the sheet, 68 % of the energy can be saved compared to roller hearth furnaces. The heating time of 10 s is not sufficient for the common coatings to form a good bond with the sheet material. A new approach is conductive heating in an XHV-adequate atmosphere. The process gases nitrogen and silane reduce the oxygen content in the heating chamber to an XHV-adequate level, which means that uncoated sheets can also be heated without scale. By integrating coating nozzles into the heating chamber, the XHV (extremely high vacuum)-adequate environment and the heating energy can be used to coat the sheets. Within the scope of this research coatings adapted to the rapid heating are developed and tested for the forming temperatures by means of an integrated stretching device inside the chamber.
UR - http://www.scopus.com/inward/record.url?scp=85197895521&partnerID=8YFLogxK
U2 - 10.33313/512/A0603
DO - 10.33313/512/A0603
M3 - Conference contribution
AN - SCOPUS:85197895521
SP - 126
EP - 132
BT - 9th International Conference on Hot Sheet Metal Forming of High-Performance Steel
A2 - Casellas, Daniel
A2 - Hardell, Jens
Y2 - 27 May 2024 through 29 May 2024
ER -