Ferritic stainless steel sheet, method for producing the same, and part

Patent metadata

Field	Value
Publication number	US-2022275492-A1
Application number	US-202217674502-A
Country	US
Kind code	A1
Filing date	Feb 17, 2022
Priority date	Feb 17, 2021
Publication date	Sep 1, 2022
Grant date	—

Abstract

The present invention has as its technical problem to prevent cracking when producing a steel sheet by ferritic stainless steel sheet and provide a ferritic stainless steel sheet excellent in toughness and a part using the same. To solve this technical problem, the present invention provides steel comprised of, by mass %, C: 0.001 to 0.030%, Si: 0.01 to 1.00%, Mn: 0.01 to 1.00%, P: 0.010 to 0.050%, S: 0.0002 to 0.0100%, Cr: 10.0 to 20.0%, N: 0.001 to 0.030%, Nb: 0.10 to 0.40%, B: 0.0002 to 0.0030%, Al: 0.005 to 0.100%, and a balance of Fe and unavoidable impurities in which the amount of solute Nb being less than or equal to a smaller value of 0.20 and (Nb content-0.08) mass %.

First claim

1 . A ferritic stainless steel sheet comprising, by mass %,
C: 0.001 to 0.030%, Si: 0.01 to 1.00%, Mn: 0.01 to 1.00%, P: 0.010 to 0.050%, S: 0.0002 to 0.0100%, Cr: 10.0 to 20.0%, N: 0.001 to 0.030%, Nb: 0.10 to 0.40%, B: 0 to 0.0030%, Al: 0 to 0.100%, Ti: 0 to 0.20%, Ni: 0 to 1.00%, Mo: 0 to 2.0%, Cu: 0 to 3.0%, V: 0 to 1.00%, Mg: 0 to 0.0030%, Sn: 0 to 0.30%, Sb: 0 to 0.30%, Zr: 0 to 0.10%, Ta: 0 to 0.10%, Hf: 0 to 0.10%, W: 0 to 2.00%, Co: 0 to 0.20%, Ca: 0 to 0.0030%, REM: 0 to 0.050%, Ga: 0 to 0.10%, a balance of Fe and unavoidable impurities, the amount of solute Nb being less than or equal to a smaller value of 0.20 mass % and (Nb content-0.08) mass %.

2 . The ferritic stainless steel sheet according to claim 1 , wherein when a thickness of the stainless steel sheet is “t”, a number density of Nb-containing precipitates of grain sizes of 1 μm or more is 0.005/μm 2 or less in a depth range of t/2 to t/4 from the surface in a cross-section in a thickness direction.

3 . The ferritic stainless steel sheet according to claim 1 , wherein a grain size of the Nb-containing precipitate is 2 μm or less.

4 . The ferritic stainless steel sheet according to claim 2 , wherein a grain size of the Nb-containing precipitate is 2 μm or less.

5 . A method for producing the ferritic stainless steel sheet according to claim 1 comprising,
heating a slab comprising, by mass %,
C: 0.001 to 0.030%,
Si: 0.01 to 1.00%,
Mn: 0.01 to 1.00%,
P: 0.010 to 0.050%,
S: 0.0002 to 0.0100%,
Cr: 10.0 to 20.0%,
N: 0.001 to 0.030%,
Nb: 0.10 to 0.40%,
B: 0 to 0.0030%,
Al: 0 to 0.100%,
Ti: 0 to 0.20%,
Ni: 0 to 1.00%,
Mo: 0 to 2.0%,
Cu: 0 to 3.0%,
V: 0 to 1.00%,
Mg: 0 to 0.0030%,
Sn: 0 to 0.30%,
Sb: 0 to 0.30%,
Zr: 0 to 0.10%,
Ta: 0 to 0.10%,
Hf: 0 to 0.10%,
W: 0 to 2.00%,
Co: 0 to 0.20%,
Ca: 0 to 0.0030%,
REM: 0 to 0.050%,
Ga: 0 to 0.10%,
a balance of Fe and unavoidable impurities,
the amount of solute Nb being less than or equal to a smaller value of 0.20 mass % and (Nb content-0.08) mass %, to 1230° C. or more,
hot rolling so that a ratio of a start temperature of finish rolling (° C.) and a finish temperature of finish rolling (° C.) (start temperature of finish rolling (° C.)/finish temperature of finish rolling (° C.)) becomes 1.10 or more, then
coiling at 500° C. or less.

6 . The method for producing the ferritic stainless steel sheet according to claim 5 further comprising cooling the hot rolled steel sheet at a cooling rate of 20° C./sec or more, then coiling the hot rolled steel sheet.

7 . The method for producing the ferritic stainless steel sheet according to claim 5 further comprising heating the coiled steel sheet to 900 to 1050° C., then holding and annealing the coiled steel sheet for 60 seconds or more.

8 . The method for producing the ferritic stainless steel sheet according to claim 6 further comprising heating the coiled steel sheet to 900 to 1050° C., then holding and annealing the coiled steel sheet for 60 seconds or more.

9 . A part using the ferritic stainless steel sheet according to claim 1 for at least a portion.

10 . The part according to claim 9 wherein the part using the ferritic stainless steel sheet is joined with another part by brazing or arc welding.

Assignees

• Nippon Steel Stainless Steel Corp

Inventors

• Hamada Junichi
• HAYASHI Atsutaka

Classifications

• C21D8/02

  during manufacturing of plates or strips (C21D8/12 takes precedence) · CPC title

• C21D8/0226

  Hot rolling · CPC title

• C22C38/04

  containing manganese · CPC title

• C22C38/52 Primary

  with cobalt · CPC title

• C22C38/06

  containing aluminium · CPC title