Steel sheet for crown cap, method for manufacturing steel sheet for crown cap, and crown cap

Patent metadata

Field	Value
Publication number	US-10655199-B2
Application number	US-201615551641-A
Country	US
Kind code	B2
Filing date	Jan 27, 2016
Priority date	Feb 26, 2015
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

Provided are a steel sheet, having sufficient strength and formability regardless of reduction of thickness, for crown caps; a method for manufacturing the same; and a crown cap. The steel sheet for crown caps has a composition containing C: 0.0010% to less than 0.0050%, Si: 0.10% or less, Mn: 0.05% to less than 0.50%, P: 0.050% or less, S: 0.050% or less, Al: more than 0.002% to less than 0.070%, N: less than 0.0040%, and B: 0.0005% to 0.0020% on a mass basis, the balance being Fe and inevitable impurities, and also has a yield strength of 500 MPa or more in a rolling direction, an average Lankford value (r) of 1.1 or more, and an in-plane anisotropy (Δr) of Lankford value of −0.3 to 0.3.

First claim

The invention claimed is:

1. A steel sheet for a crown cap, the steel sheet having a composition comprising:
C: 0.0010% to less than 0.0050%, by mass %;
Si: 0.10% or less, by mass %;
Mn: 0.05% to less than 0.50%, by mass %;
P: 0.050% or less, by mass %;
S: 0.050% or less, by mass %;
Al: 0.020% to less than 0.070%, by mass %;
N: less than 0.0040%, by mass %;
B: 0.0005% to 0.0020%, by mass %; and
Fe and inevitable impurities,
wherein:
the steel sheet has a yield strength of 500 MPa or more in a rolling direction,
the steel sheet has an average Lankford value (r) of 1.1 or more as given by the following equation (1), and
the steel sheet has an in-plane anisotropy (Δr) of Lankford value of −0.3 to 0.3 as given by the following equation (3):
r= 101.44/(145.0 ×E× 10 −6 −38.83) 2 −0.564  (1)

where E =( E 0 +2 E 45 +E 90 )/4  (2)

where E 0 , E 45 , and E 90 are the Young's modulus (MPa) in a 0° direction, the Young's modulus (MPa) in a 45° direction, and the Young's modulus (MPa) in a 90° direction, with respect to the rolling direction, respectively,
Δ r= 0.031−4.685×10 −5 ×ΔE   (3)

where Δ E =( E 0 −2 E 45 +E 90 )/2  (4).

2. The steel sheet for a crown cap according to claim 1 , wherein the steel sheet has a thickness of 0.20 mm or less.

3. A crown cap formed from the steel sheet for a crown cap according to claim 2 .

4. A crown cap formed from the steel sheet for a crown cap according to claim 1 .

5. The steel sheet for a crown cap according to claim 1 , wherein the average Lankford value (r) of the steel sheet is 1.2 or more.

6. The steel sheet for a crown cap according to claim 1 , wherein the steel sheet is subjected to a plating treatment.

7. The steel sheet for a crown cap according to claim 1 , wherein the composition comprises C: 0.0010% to 0.0025%, by mass %.

8. A method for manufacturing a steel sheet for a crown cap, the method comprising:
hot rolling a steel slab having the composition specified in claim 1 to form a steel sheet,
performing finish rolling on the steel sheet,
performing cooling of the steel sheet at a cooling rate of 30° C./s to 80° C./s after the finish rolling,
performing coiling of the steel sheet at a temperature of 570° C. to 670° C.,
performing primary cold rolling of the steel sheet,
performing annealing of the steel sheet at a temperature of 620° C. to 720° C., and
performing secondary cold rolling of the steel sheet at a rolling reduction of more than 20% to 50%.

Assignees

• Jfe Steel Corp

Inventors

• Tanaka Takumi
• Hiraguchi Tomonari
• Kojima Katsumi
• Nakamaru Hiroki
• Kariya Nobusuke

Classifications

• C22C38/06 Primary

  containing aluminium · CPC title

• C21D9/46

  for sheet metals · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title

• C21D8/0268

  between cold rolling steps · CPC title

• C22C38/02

  containing silicon · CPC title