Method for producing a cold-rolled flat steel product for deep-drawing and ironing applications, flat steel product, and use of a flat steel product of said type

Patent metadata

Field	Value
Publication number	US-10184159-B2
Application number	US-201414772788-A
Country	US
Kind code	B2
Filing date	Mar 6, 2014
Priority date	Mar 7, 2013
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

A method is disclosed for the operationally reliable production of a cold-rolled flat steel product of ≤0.5 mm in thickness for deep-drawing and ironing applications. In the method, a steel melt which (in wt %) comprises up to 0.008% C, up to 0.005% Al, up to 0.043% Si, 0.15-0.5% Mn, up to 0.02% P, up to 0.03% S, up to 0.020% N and in each case optionally up to 0.03% Ti and up to 0.03% Nb and, as a remainder, iron and unavoidable impurities, is, with the omission of a Ca treatment, subjected to a secondary metallurgical treatment which, in addition to a vacuum treatment, comprises a ladle furnace treatment and during which the steel melt to be treated is kept under a slag, the Mn and Fe contents of which are, in sum total, <15 wt %. From the steel melt, a thin slab or a cast strip are produced, which are subsequently hot-rolled to form a hot strip with a thickness of <2.5 mm and wound to form a coil. Subsequently, the hot strips are cold-rolled to form a flat steel product of up to 0.5 mm in thickness.

First claim

The invention claimed is:

1. A method for producing a cold-rolled flat steel product of up to 0.5 mm in thickness for deep-drawing and ironing applications, comprising the following working steps:
a) producing a metal melt which (in wt %) comprises up to 0.008% C, up to 0.005% Al, 0.008-0.043% Si, 0.15-0.5% Mn, up to 0.02% P, up to 0.03% S, up to 0.020% N and in each case optionally up to 0.03% Ti and up to 0.03% Nb and, as a remainder, iron and unavoidable impurities, the contents of which are to be attributed to up to 0.08% Cr, up to 0.08% Ni, up to 0.08% Cu, up to 0.02% Sn, up to 0.01% Mo, up to 0.0020% V, up to 0.007% B, up to 0.05% Co and up to 0.0060% Ca, wherein the metal melt is, with the omission of a Ca treatment, subjected to a secondary metallurgical treatment which, in addition to a vacuum treatment, comprises a ladle furnace treatment and during which the steel melt to be treated is kept under a slag, the Mn content % Mn and Fe content % Fe of the slag defined by
% Mn+% Fe<15 wt %;

b) continuously casting the metal melt to form a strand, and severing a thin slab from the strand, or to form a cast strip;
c) hot-rolling the thin slab or the cast strip to form a hot strip with a thickness of less than 2.5 mm;
d) winding the hot strip to form a coil; and
e) cold-rolling the hot strip to form the cold-rolled flat steel product of up to 0.5 mm in thickness.

2. The method as claimed in claim 1 , wherein the Al content of the steel melt amounts to at most 0.002 wt %.

3. The method as claimed in claim 1 , wherein the Fe content % Fe of the slag under which the steel melt is kept during the ladle furnace treatment amounts to less than 10 wt %.

4. The method as claimed in claim 1 , wherein the oxygen content of the steel melt at the end of the ladle furnace treatment lies below 100 ppm.

5. The method as claimed in claim 1 , wherein the thin slab is, before the hot rolling, brought to a temperature of 1000-1250° C.

6. The method as claimed in claim 1 , wherein the hot-rolling start temperature of the thin slab at the start of the hot-rolling process is 950-1200° C.

7. The method as claimed in claim 1 , wherein the hot-rolling end temperature of the hot strip at the end of the hot-rolling process is 800-950° C.

8. The method as claimed in claim 1 , wherein the hot strip is wound at a winding temperature of 500-750° C.

9. The method as claimed in claim 1 , wherein the thickness of the cold-rolled flat steel product amounts to less than 0.26 mm.

10. The method as claimed in claim 1 , wherein the cold rolling is performed in at least two stages, and the cold-rolled flat steel product is subjected to recrystallization annealing between the stages of the cold-rolling process.

11. The method as claimed in claim 10 , wherein the degree of deformation achieved by way of the first stage of the cold-rolling process is greater than 85%, and the degree of deformation achieved by way of the second stage of the cold-rolling process amounts to 0.4-50%.

12. The method as claimed in claim 1 , wherein the cold-rolled flat steel product is subjected to electrolytic tin plating.

13. A flat steel product produced through the use of the method configured as claimed in claim 1 .

14. A method of producing a steel container comprising forming at least a portion of the steel container from the flat steel product as claimed in claim 13 .

15. A flat steel product as claimed in claim 13 , wherein earing of the flat steel product, as defined in accordance with ISO 11531, is <0.86 mm.

16. The method as claimed in claim 14 , wherein the container is a can for foodstuffs, animal feed, beverages or other filling materials, an aerosol can or a spray can.

17. The method as claimed in claim 16 , wherein the filling materials are chemical or biological products.

Assignees

• Thyssenkrupp Steel Europe Ag
• Thyssenkrupp Rasselstein Gmbh

Inventors

• Holleck Erhard
• Sowka Eberhard
• Kaup Burkhard
• Schiester Stephan

Classifications

• B21B1/46 Primary

  for rolling metal immediately subsequent to continuous casting (metal-rolling stands B21B13/22; continuous casting B22D11/00, e.g. into moulds with rolls B22D11/06) · CPC title

• C21D8/0436 Primary

  Cold rolling · CPC title

• C22B9/10

  with refining or fluxing agents; Use of materials therefor, {e.g. slagging or scorifying agents}(C22B9/18 takes precedence){(C22B9/006 takes precedence)} · CPC title

• C25D5/36

  of iron or steel · CPC title

• C22C38/04

  containing manganese · CPC title