Invention Grant
- Patent Title: Method for cold deformation of an austenitic steel
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Application No.: US16337619Application Date: 2017-09-29
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Publication No.: US11352678B2Publication Date: 2022-06-07
- Inventor: Thomas Fröhlich , Stefan Lindner , Thorsten Piniek
- Applicant: Outokumpu Oyj
- Applicant Address: FI Helsinki
- Assignee: Outokumpu Oyj
- Current Assignee: Outokumpu Oyj
- Current Assignee Address: FI Helsinki
- Agency: The Webb Law Firm
- Priority: EP16191364 20160929
- International Application: PCT/EP2017/074832 WO 20170929
- International Announcement: WO2018/060454 WO 20180405
- Main IPC: C21D7/04
- IPC: C21D7/04 ; B21B37/24 ; B21B1/22

Abstract:
A method for partial hardening of an austenitic steel by utilizing during cold deformation the TWIP (Twinning Induced Plasticity), TWIP/TRIP or TRIP (Transformation Induced Plasticity) hardening effect. Cold deformation is carried out by cold rolling at least one surface of the steel with forming degree (Φ) of 5≤Φ≤60% in order to achieve in the steel at least two consecutive areas with different mechanical values in thickness, yield strength (Rp0.2), tensile strength (Rm) and elongation, having a ratio (r) between the ultimate load ratio (ΔF) and the thickness ratio (Δt) of 1.0>r>2.0, and in which the areas are mechanically connected to each other by a transition area having a thickness that is variable from the thickness of the first area in the deformation direction to the thickness of the second area in the deformation direction.
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