US 11,767,573 B2
Ferritic stainless steel sheet and method of producing same, and al or al alloy coated stainless steel sheet
Akito Mizutani, Tokyo (JP); Rinta Sato, Tokyo (JP); and Mitsuyuki Fujisawa, Tokyo (JP)
Assigned to JFE STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/275,051
Filed by JFE STEEL CORPORATION, Tokyo (JP)
PCT Filed Aug. 26, 2019, PCT No. PCT/JP2019/033353
§ 371(c)(1), (2) Date Mar. 10, 2021,
PCT Pub. No. WO2020/054384, PCT Pub. Date Mar. 19, 2020.
Claims priority of application No. 2018-171805 (JP), filed on Sep. 13, 2018.
Prior Publication US 2022/0056547 A1, Feb. 24, 2022
Int. Cl. C21D 9/46 (2006.01); C21D 6/00 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C21D 1/02 (2006.01); C23C 2/12 (2006.01)
CPC C21D 9/46 (2013.01) [C21D 1/02 (2013.01); C21D 6/004 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C23C 2/12 (2013.01); C21D 2211/005 (2013.01)] 8 Claims
 
1. A method of producing a ferritic stainless steel sheet comprising a chemical composition containing, in mass %,
C: 0.030% or less,
Si: 3.0% or less,
Mn: 1.0% or less,
P: 0.040% or less,
S: 0.010% or less,
Cr: 11.0% to 30.0%,
Al: 10.7% to 20.0%,
Ni: 0.05% to 0.50%,
N: 0.020% or less, and
at least one selected from the group consisting of Zr: 0.01% to 0.20% and Hf: 0.01% to 0.20%,
with a balance being Fe and inevitable impurities, the method comprising
subjecting an Al or Al alloy coated stainless steel sheet comprising:
a coating substrate; and
an Al or Al alloy coated layer on a surface of the coating substrate,
wherein the coating substrate is a ferritic stainless steel sheet having a chemical composition containing, in mass %,
C: 0.030% or less,
Si: 1.0% or less,
Mn: 1.0% or less,
P: 0.040% or less,
S: 0.010% or less,
Cr: 11.0% to 30.0%,
Al: 2.5% to 6.5%,
Ni: 0.05% to 0.50%,
N: 0.020% or less, and
at least one selected from the group consisting of Zr: 0.01% to 0.20% and Hf: 0.01% to 0.20%,
with a balance being Fe and inevitable impurities, and
a thickness and an Al content of the coating substrate and a thickness of the Al or Al alloy coated layer satisfy a relationship in the following expression (1):
8.0≤CAl+30×t/T≤20.0  (1)
where CAl is the Al content of the coating substrate in mass %, T is the thickness of the coating substrate in μm, and t is the thickness of the Al or Al alloy coated layer in μm, and, in the case where the Al or Al alloy coated layer is present on each of both sides of the coating substrate, is a total thickness of Al or Al alloy coated layers on the both sides of the coating substrate, to a heat treatment of holding in a temperature range of 600° C. to 1300° C. for 1 minute or more and 120 minutes or less in a vacuum of 1×10−1 Pa or less or a non-oxidizing atmosphere, and
wherein the number of times the heat treatment is performed is 1.