US 12,258,649 B2
High-resistance steel strip comprising a temperature homogenisation chamber
Jean-Pierre Crutzen, Chaudfontaine (BE); Lutz Kümmel, Jüchen (DE); Frank Maschler, Duisburg (DE); and Michel Renard, Liège (BE)
Assigned to DREVER INTERNATIONAL, Liège (BE); and John Cockerill SA, Seraing (BE)
Filed by DREVER INTERNATIONAL, Liège (BE); and John Cockerill SA, Seraing (BE)
Filed on Dec. 7, 2023, as Appl. No. 18/532,051.
Application 18/532,051 is a division of application No. 16/722,637, filed on Dec. 20, 2019, abandoned.
Claims priority of application No. 20195038 (BE), filed on Jan. 23, 2019.
Prior Publication US 2024/0102124 A1, Mar. 28, 2024
Int. Cl. C21D 9/56 (2006.01); C21D 1/26 (2006.01); C21D 1/34 (2006.01); C21D 1/52 (2006.01); C21D 1/74 (2006.01); C21D 1/76 (2006.01); C21D 1/773 (2006.01); C21D 9/46 (2006.01); C23C 8/10 (2006.01); C23C 8/18 (2006.01); C23C 8/80 (2006.01); F27B 9/28 (2006.01)
CPC C21D 9/561 (2013.01) [C21D 1/26 (2013.01); C21D 1/34 (2013.01); C21D 1/52 (2013.01); C21D 1/74 (2013.01); C21D 1/76 (2013.01); C21D 1/773 (2013.01); C21D 9/46 (2013.01); C21D 9/56 (2013.01); C21D 9/562 (2013.01); C21D 9/563 (2013.01); C23C 8/10 (2013.01); C23C 8/18 (2013.01); C23C 8/80 (2013.01); F27B 9/28 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method for thermally treating a scrolling high-resistance steel strip, said method comprising the following steps:
a) heating the strip in a zone for heating with a direct flame, the heating step being carried out with an atmosphere having an oxygen volume concentration less than 0.01% by volume;
b) temperature homogenisation of the strip in a homogenisation chamber comprising at least one radiant heating tube, so as to homogenise the strip in temperature after the passing through the zone for heating with a direct flame, the temperature homogenisation step being carried out with an atmosphere having an oxygen volume concentration less than 0.01% by volume;
c) after the temperature homogenization of the strip, oxidation of the strip in an oxidation chamber with an oxidizing atmosphere to form an oxide layer on the strip, wherein the temperature homogenisation results in growth of a more homogenous oxide layer thickness over the surface of the strip as compared to a thickness of an oxide layer without the temperature homogenisation;
d) after the oxidation of the strip, a further thermal treatment step which increases a temperature of the strip and comprising reduction of the strip in a reduction zone to remove the oxide layer.