Concurrent Improvement of strength, formability and SCC resistance of Al-Zn-Mg-Cu alloy by hot stamping after rapid heating and re-aging on paint baking treatment

–

Concurrent Improvement of strength, formability and SCC resistance of Al-Zn-Mg-Cu alloy by hot stamping after rapid heating and re-aging on paint baking treatment

HIROSAWA Shoichi, KIM Junmo, MAENO Tomoyoshi, SUZUKI Yasushi, YABUKI Yuuji

Abstract. In this study, the combined application of rapid heating for hot stamping and the subsequent re-aging during a paint baking treatment was newly developed for T6-tempered A7075 Al-Zn-Mg-Cu alloy sheets. From a systematic investigation, rapid heating to 255-260 ℃ and short-time holding for ~120 s was found to give the best combination of formability, hardness and stress corrosion cracking (SCC) resistance of the final products. In particular, re-aging treatment at 170 ℃ for 1.2 ks was well exploited not only for further improvement of SCC resistance but also for rebound of the decreased hardness by rapid heating. Therefore, the developed three-step heat treatment is regarded as a promising approach to producing high-strength, easily formable and corrosion-resistant Al-Zn-Mg-Cu alloy parts for automobiles.

Keywords
Extra Super Duralumin, T6 Temper, High Strength, Formability, Corrosion Resistance, Medium Temperature

Published online 9/15/2024, 6 pages
Copyright © 2024 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: HIROSAWA Shoichi, KIM Junmo, MAENO Tomoyoshi, SUZUKI Yasushi, YABUKI Yuuji, Concurrent Improvement of strength, formability and SCC resistance of Al-Zn-Mg-Cu alloy by hot stamping after rapid heating and re-aging on paint baking treatment, Materials Research Proceedings, Vol. 44, pp 227-232, 2024

DOI: https://doi.org/10.21741/9781644903254-25

The article was published as article 25 of the book Metal Forming 2024

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

References
[1] R.P. Garret, J. Lin, T.A. Dean, Solution heat treatment and cold die quenching in forming AA6xxx sheet components: Feasibility study, Adv. Mater. Res. 6-8 (2005) 673-680. https://doi.org/ 0.4028/ ww.scientific.net/AMR.6-8.673
[2] S. Hirosawa, T. Maeno, J. Kim, K. Nariya, Y. Suzuki, International Patent WO2023/053845 A1. Forming method of aluminum alloy sheets, (2023).
[3] Japanese standard association: JIS Handbook, Non-ferrous metals & metallurgy III，(2018), 886.
[4] B.M. Cina, U. S. Patent 3856584. Reducing the susceptibility of alloys, Particularly aluminum alloys, to stress corrosion cracking, (1974).