# US 2019/0316236 A1 · Ferritic stainless steel

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- Number: US 2019/0316236 A1
- Document ID: US20190316236A1
- Status: Published application
- Kind: A1
- Application number: 16/470,343
- Filed: 2017-12-04
- Published: 2019-10-17
- Earliest claimed: 2016-12-21
- Assignees: Jfe Steel Corporation
- Applicants: JFE Steel Corporation
- Inventors: Tetsuyuki Nakamura; Shin Ishikawa; Reiko Sugihara
- Web page: https://patentgrep.com/patent/US20190316236A1

## CPC

- C21D 6/002: {containing Cr (C21D6/004 takes precedence)}
- C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium
- C21D 6/004: {containing Cr and Ni}
- C21D 6/007: {containing Co}
- C21D 6/02: Hardening by precipitation
- C21D 8/02: during manufacturing of plates or strips (C21D8/12 takes precedence)
- C21D 8/0226: {Hot rolling}
- C21D 8/0236: {Cold rolling}
- C21D 9/46: for sheet metals
- C22C 38/00: Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00)
- C22C 38/001: {containing N}
- C22C 38/002: {containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60}
- C22C 38/004: {Very low carbon steels, i.e. having a carbon content of less than 0,01%}
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- C22C 38/42: with copper
- C22C 38/44: with molybdenum or tungsten
- C22C 38/46: with vanadium
- C22C 38/48: with niobium or tantalum
- C22C 38/50: with titanium or zirconium
- C22C 38/52: with cobalt
- C22C 38/54: with boron
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

Provided is a ferritic stainless steel sheet. The steel sheet has a chemical composition containing, by mass %, C: 0.010% or less, Si: 1.0% or less, Mn: 1.0% or less, P: 0.040% or less, S: 0.030% or less, Cr: 17.0% or more and 18.5% or less, N: 0.015% or less, Nb: 0.40% or more and 0.80% or less, Ti: 0.10% or more and 0.40% or less, Al: 0.20% or less, Ni: 0.05% or more and 0.40% or less, Co: 0.01% or more and 0.30% or less, Mo: 0.02% or more and 0.30% or less, Cu: 0.02% or more and 0.40% or less, and the balance being Fe and inevitable impurities, in which expression (1) below is satisfied. C %+N %: 0.018% or less (1) In expression (1), C % and N % respectively denote the contents (mass %) of C and N.

## Claims

### Claim 1

Ferritic stainless steel having a chemical composition containing, by mass %,
C: 0.010% or less,
Si: 1.0% or less,
Mn: 1.0% or less,
P: 0.040% or less,
S: 0.030% or less,
Cr: 17.0% or more and 18.5% or less,
N: 0.015% or less,
Nb: 0.40% or more and 0.80% or less,
Ti: 0.10% or more and 0.40% or less,
Al: 0.20% or less,
Ni: 0.05% or more and 0.40% or less,
Co: 0.01% or more and 0.30% or less,
Mo: 0.02% or more and 0.30% or less,
Cu: 0.02% or more and 0.40% or less, and
the balance being Fe and inevitable impurities,
wherein expression (1) below is satisfied:
C %+N %: 0.018% or less (1),
where, in expression (1), C % and N % respectively denote the contents (mass %) of C and N.

### Claim 2 (depends on 1)

The ferritic stainless steel according to claim 1, wherein the chemical composition further contains, by mass %, one, two, or all selected from
Ca: 0.0005% or more and 0.0030% or less,
Mg: 0.0002% or more and 0.0020% or less, and
B: 0.0002% or more and 0.0020% or less.

### Claim 3 (depends on 1)

The ferritic stainless steel according to claim 1, wherein the chemical composition further contains, by mass %, one, two, or all selected from
V: 0.01% or more and 0.50% or less,
W: 0.02% or more and 0.30% or less, and
Zr: 0.005% or more and 0.50% or less.

### Claim 4 (depends on 2)

The ferritic stainless steel according to claim 2, wherein the chemical composition further contains, by mass %, one, two, or all selected from
V: 0.01% or more and 0.50% or less,
W: 0.02% or more and 0.30% or less, and
Zr: 0.005% or more and 0.50% or less.