Investigation Of The Process Window For Deformation Induced Ferrite To Improve The Joinability Of Press-Hardened Components

authored by: Bernd Arno Behrens, Kai Brunotte, Hendrik Wester, Eugen Stockburger
Abstract: Due to their high tensile strengths increasing the crashworthiness of the vehicles, ultra-high strength steels are increasingly used in the automotive industry, for example in components like B-pillars or tunnel. 22MnB5 is a premier candidate for this cause, since it can be press-hardened and phase-transformed into the martensitic phase, resulting in high hardness and tensile strength. However, complications can arise in the assembly of press-hardened components since conventional mechanical joining processes have their limitations due to high forces required for joining press-hardened steels, especially in multi-sheet layers. Therefore, this study focuses on the determination of an optimum process window to influence the 22MnB5 microstructure thermo-mechanically during press hardening, causing a local softening. This so-called deformation-induced ferrite improves ductility at the desired locations to ease the mechanical joining operation in the assembly. Investigations are performed on a forming dilatometer varying the cooling rate, the introduced amount of plastic strain and the forming temperature along with metallographic as well as microhardness measurements. Based on the laboratory tests, a process window of the deformation induced ferrite is derived for an application in a forming press.
Organisation(s): Institute of Metal Forming and Metal Forming Machines
Type: Conference contribution
Pages: 579-584
No. of pages: 6
Publication date: 27.07.2020
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Mechanics of Materials, Metals and Alloys, Surfaces, Coatings and Films
Electronic version(s): https://doi.org/10.37904/metal.2020.3523 (Access: Open)
: Details in the research portal "Research@Leibniz University"

BibTeX

@inproceedings{4fa288fd572740938b9110c8001ac865,
title = "Investigation Of The Process Window For Deformation Induced Ferrite To Improve The Joinability Of Press-Hardened Components",
abstract = "Due to their high tensile strengths increasing the crashworthiness of the vehicles, ultra-high strength steels are increasingly used in the automotive industry, for example in components like B-pillars or tunnel. 22MnB5 is a premier candidate for this cause, since it can be press-hardened and phase-transformed into the martensitic phase, resulting in high hardness and tensile strength. However, complications can arise in the assembly of press-hardened components since conventional mechanical joining processes have their limitations due to high forces required for joining press-hardened steels, especially in multi-sheet layers. Therefore, this study focuses on the determination of an optimum process window to influence the 22MnB5 microstructure thermo-mechanically during press hardening, causing a local softening. This so-called deformation-induced ferrite improves ductility at the desired locations to ease the mechanical joining operation in the assembly. Investigations are performed on a forming dilatometer varying the cooling rate, the introduced amount of plastic strain and the forming temperature along with metallographic as well as microhardness measurements. Based on the laboratory tests, a process window of the deformation induced ferrite is derived for an application in a forming press.",
keywords = "Deformation induced ferrite, Manganese boron steel, Press hardening",
author = "Behrens, {Bernd Arno} and Kai Brunotte and Hendrik Wester and Eugen Stockburger",
note = "Funding Information: The presented results are based on the framework of the research project “Local material influence during press hardening to improve the joinability of components made of 22MnB5” (grant number 19797 BG). The authors would like to thank the Research Association for Steel Application (FOSTA) and the German Federation of Industrial Research Associations (AiF) for the financial support.; 29th International Conference on Metallurgy and Materials, METAL 2020 ; Conference date: 20-05-2020 Through 22-05-2020",
year = "2020",
month = jul,
day = "27",
doi = "10.37904/metal.2020.3523",
language = "English",
pages = "579--584",
booktitle = "Proceedings 29th International Conference on Metallurgy and Materials",
publisher = "TANGER Ltd.",
}