Ferritic stainless steel sheet and method of producing same, and al or al alloy coated stainless steel sheet

Patent metadata

Field	Value
Publication number	US-11767573-B2
Application number	US-201917275051-A
Country	US
Kind code	B2
Filing date	Aug 26, 2019
Priority date	Sep 13, 2018
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

A ferritic stainless steel sheet comprises 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: 8.0% 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 consisting of Fe and inevitable impurities.

First claim

The invention claimed is:

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≤ C Al +30× t/T≤ 20.0  (1)

where C Al 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.

2. The method according to claim 1 , wherein the holding time in the heat treatment is 1 minute or more and 30 minutes or less.

3. The method according to claim 2 , wherein an Al content of a chemical composition of a produced ferritic stainless steel sheet is 11.2% to 20.0%.

4. The method according to claim 1 , wherein an Al content of a chemical composition of a produced ferritic stainless steel sheet is 11.2% to 20.0%.

5. 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%, and
one or more selected from the group consisting of
REM: 0.01% to 0.20%,
Cu: 0.01% to 0.10%,
Ti: 0.01% to 0.50%,
Nb: 0.01% to 0.50%,
V: 0.01% to 0.50%,
Mo: 0.01% to 6.0%,
W: 0.01% to 6.0%,
B: 0.0001% to 0.0050%,
Ca: 0.0002% to 0.0100%, and
Mg: 0.0002% to 0.0100%,
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,
at least one selected from the group consisting of Zr: 0.01% to 0.20% and Hf: 0.01% to 0.20%, and
one or more selected from the group consisting of
REM: 0.01% to 0.20%,
Cu: 0.01% to 0.10%,
Ti: 0.01% to 0.50%,
Nb: 0.01% to 0.50%,
V: 0.01% to 0.50%,
Mo: 0.01% to 6.0%,
W: 0.01% to 6.0%,
B: 0.0001% to 0.0050%,
Ca: 0.0002% to 0.0100%, and
Mg: 0.0002% to 0.0100%,
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≤ C Al +30× t/T≤ 20.0  (1)

where C Al 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.

6. The method according to claim 5 , wherein the holding time in the heat treatment is 1 minute or more and 30 minutes or less.

7. The method according to claim 6 , wherein an Al content of a chemical composition of a produced ferritic stainless steel sheet is 11.2% to 20.0%.

8. The method according to claim 5 , wherein an Al content of a chemical composition of a produced ferritic stainless steel sheet is 11.2% to 20.0%.

Assignees

• Jfe Steel Corp

Inventors

• Mizutani Akito
• SATO Rinta
• Fujisawa Mitsuyuki

Classifications

• C21D9/46 Primary

  for sheet metals · CPC title

• C21D1/02

  Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation · CPC title

• C21D6/004

  containing Cr and Ni · CPC title

• C22C38/001

  containing N · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title