# US 11,111,570 B2 · Ferritic stainless steel sheet, hot coil, and automobile exhaust flange member

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,111,570 B2
- Document ID: US11111570B2
- Status: Granted
- Kind: B2
- Application number: 16/489,674
- Filed: 2017-02-28
- Published: 2020-04-16
- Granted: 2021-09-07
- Earliest claimed: 2017-02-28
- Assignees: Nippon Steel Corporation
- Applicants: Nippon Steel Corporation
- Inventors: Shinichi Teraoka; Shinichi Tamura; Akihiro Nishimura
- Web page: https://patentgrep.com/patent/US11111570B2

## CPC

- C22C 38/60: containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
- C21D 6/004: {containing Cr and Ni}
- C21D 8/02: during manufacturing of plates or strips (C21D8/12 takes precedence)
- C21D 8/0226: {Hot rolling}
- C21D 8/0263: {following hot 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 38/005: {containing rare earths, i.e. Sc, Y, Lanthanides}
- C22C 38/008: {containing tin}
- 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
- F01N 13/1805: {Fixing exhaust manifolds, exhaust pipes or pipe sections to each other, to engine or to vehicle body (pipe joints in general F16L; fixing auxiliaries in motor vehicles in general B60K)}
- C21D 2211/005: Ferrite
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- 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)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)

## Abstract

A ferritic stainless steel plate having a sheet thickness t of 5.0 to 12.0 mm, including a chemical composition consisting of, in mass percent, C: 0.001 to 0.010%, Si: 0.01 to 1.0%, Mn: 0.01 to 1.0%, P: 0.04% or less, S: 0.010% or less, Cr: 10.0 to 20.0%, Ni: 0.01 to 1.0%, Ti: 0.10 to 0.30%, V: 0.01 to 0.40%, Al: 0.005 to 0.3%, N: 0.001 to 0.02%, and as necessary, one or more of B, Mo, Cu, Mg, Sn, Sb, Zr, Ta, Nb, Hf, W, Co, Ca, REM, and Ga, with the balance being Fe and unavoidable impurities, wherein in a steel micro-structure, on a cross section parallel to a rolling direction, an area ratio of structures each satisfying: major grain diameter/minor grain diameter being less than 5.0 is 90% or more, and an average minor grain diameter of the structures is 55 μm or less. The ferritic stainless steel sheet is excellent in toughness and suitable for an automobile exhaust flange member and the like.

## Claims

### Claim 1

A ferritic stainless steel sheet having a sheet thickness t of 5.0 to 12.0 mm, comprising
a chemical composition consisting of, in mass percent:
C: 0.001 to 0.010%;
Si: 0.01 to 1.0%;
Mn: 0.01 to 1.0%;
P: 0.04% or less;
S: 0.010% or less;
Cr: 10.0 to 20.0%;
Ni: 0.01 to 1.0%;
Ti: 0.10 to 0.30%;
V: 0.01 to 0.40%;
Al: 0.005 to 0.3%;
N: 0.001 to 0.02%;
B: 0 to 0.0030%;
Mo: 0 to 2.0%;
Cu: 0 to 0.3%;
Mg: 0 to 0.0030%;
Sn: 0 to 0.1%;
Sb: 0 to 0.1%;
Zr: 0 to 0.1%;
Ta: 0 to 0.1%;
Nb: 0 to 0.1%;
Hf: 0 to 0.1%;
W: 0 to 0.1%;
Co: 0 to 0.2%;
Ca: 0 to 0.0030%;
REM: 0 to 0.05%; and
Ga: 0 to 0.1%,
with the balance being Fe and unavoidable impurities, wherein
in a steel micro-structure, on a cross section parallel to a rolling direction, an area ratio of structures each satisfying: major grain diameter/minor grain diameter being less than 5.0 is 90% or more, and an average minor grain diameter of the structures is 55 μm or less.

### Claim 2 (depends on 1)

A hot coil made of the ferritic stainless steel sheet according to claim 1.

### Claim 3 (depends on 1)

An automobile exhaust flange member made of the ferritic stainless steel sheet according to claim 1.

### Claim 4 (depends on 2)

An automobile exhaust flange member made using the ferritic stainless hot coil according to claim 2.

### Claim 5

A ferritic stainless steel sheet having a sheet thickness t of 5.0 to 12.0 mm, comprising
a chemical composition comprising, in mass percent:
C: 0.001 to 0.010%;
Si: 0.01 to 1.0%;
Mn: 0.01 to 1.0%;
P: 0.04% or less;
S: 0.010% or less;
Cr: 10.0 to 20.0%;
Ni: 0.01 to 1.0%;
Ti: 0.10 to 0.30%;
V: 0.01 to 0.40%;
Al: 0.005 to 0.3%;
N: 0.001 to 0.02%;
B: 0 to 0.0030%;
Mo: 0 to 2.0%;
Cu: 0 to 0.3%;
Mg: 0 to 0.0030%;
Sn: 0 to 0.1%;
Sb: 0 to 0.1%;
Zr: 0 to 0.1%;
Ta: 0 to 0.1%;
Nb: 0 to 0.1%;
Hf: 0 to 0.1%;
W: 0 to 0.1%;
Co: 0 to 0.2%;
Ca: 0 to 0.0030%;
REM: 0 to 0.05%; and
Ga: 0 to 0.1%,
with the balance comprising Fe and unavoidable impurities, wherein
in a steel micro-structure, on a cross section parallel to a rolling direction, an area ratio of structures each satisfying: major grain diameter/minor grain diameter being less than 5.0 is 90% or more, and an average minor grain diameter of the structures is 55 μm or less.

### Claim 6 (depends on 5)

A hot coil made of the ferritic stainless steel sheet according to claim 5.

### Claim 7 (depends on 5)

An automobile exhaust flange member made of the ferritic stainless steel sheet according to claim 5.

### Claim 8 (depends on 6)

An automobile exhaust flange member made using the ferritic stainless hot coil according to claim 6.