公开(公告)号：US11920206B2

公开(公告)日：2024-03-05

申请号：US17958603

申请日：2022-10-03

Applicant: thyssenkrupp Rasselstein GmbH

Inventor： Burkhard Kaup ,  Peter Kirchesch ,  Manuel Köhl ,  Dimitrios Nouskalis ,  Alexander Gossen ,  Björn Ehmke

IPC: C21D8/02 ,  C21D9/46 ,  C21D9/573 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06

CPC classification number: C21D8/0236 ,  C21D8/0226 ,  C21D8/0263 ,  C21D8/0273 ,  C21D9/46 ,  C21D9/573 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C21D2211/005

Abstract: A cold rolled steel flat product for packaging made of a low carbon steel having a thickness of less than 0.49 mm and a method of making. The steel flat product has a martensite-free microstructure and represents a standard grade for packaging with tensile strengths from 300 to 550 MPa, which can be produced from a cold-rolled steel sheet with a carbon content from 0.01% to 0.1% by weight by inductive annealing of the steel sheet and subsequent water cooling for quenching the recrystallization-annealed steel sheet. To achieve flatness of 5 I-units or less, the induction annealed steel sheet is first primarily cooled in the manufacturing process to a take-off temperature at a rate of less than 1000 K/s, with the take-off temperature being below the transformation temperature of 723° C., and thereafter a secondary cooling by water cooling with a water temperature of less than 80° C. at a rate of more than 1000 K/s.