Invention Application
- Patent Title: Low Density Steel having Good Drawability
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Application No.: US15374827Application Date: 2016-12-09
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Publication No.: US20170101694A1Publication Date: 2017-04-13
- Inventor: Astrid Perlade , Olivier Bouaziz , Xavier Garat , Josée Drillet , Jean-Louis IRIARTE
- Applicant: ArcelorMittal France
- Priority: EP07290624.1 20070516
- Main IPC: C21D9/46
- IPC: C21D9/46 ; C22C38/50 ; C22C38/48 ; C22C38/00 ; C22C38/06 ; C22C38/04 ; C22C38/02 ; C21D8/02 ; C22C38/44

Abstract:
A cold-rolled and annealed ferritic steel sheet is provided. The steel has a composition comprising, expressed by weight: 0.001≦C≦0.15%; Mn≦1%; Si≦1.5%; 7.5%≦AI≦10%; 0.020%≦Ti≦0.5%; S≦0.050%; and P≦0.1%. A balance of the composition includes iron and inevitable impurities resulting from the smelting. The structure includes kappa (κ) precipitates and equiaxed ferrite, an average grain size dα of the equiaxed ferrite is less than 50 microns, and a linear fraction f of intergranular κ precipitates is less than 30%. The linear fraction f is defined by f = Σ ( A ) di Σ ( A ) Li . Σ(A)di denotes the total length of grain boundaries containing κ precipitates relative to an area (A) and Σ(A)Li denotes the total length of the grain boundaries relative to the area (A). A content of carbon in solid solution is less than 0.005% by weight, and the cold-rolled and annealed ferritic steel sheet has a thickness between 0.6 mm and 1.5 mm. A skin part or structural part for the automotive field is also provided.
Public/Granted literature
- US09765415B2 Low density steel having good drawability Public/Granted day:2017-09-19
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