# US 2019/0169720 A1 · Ferritic steel

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

- Number: US 2019/0169720 A1
- Document ID: US20190169720A1
- Status: Published application
- Kind: A1
- Application number: 15/978,422
- Filed: 2018-05-14
- Published: 2019-06-06
- Earliest claimed: 2017-12-04
- Assignees: Hyundai Motor Company; Kia Motors Corporation
- Applicants: Hyundai Motor Company; Kia Motors Corporation
- Inventors: Dong Hwi Kim; Bong Lae Jo
- Web page: https://patentgrep.com/patent/US20190169720A1

## CPC

- C22C 38/50: with titanium or zirconium
- C21D 6/004: {containing Cr and Ni}
- C21D 6/005: {containing Mn}
- C21D 6/008: {containing Si}
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- C22C 38/46: with vanadium
- 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)

## Abstract

Disclosed herein is a ferritic steel having decreased specific gravity and having excellent mechanical strength by suppressing formation of κ-carbide. The ferrite steel may include: carbon (C) in an amount of about 0.05 to 0.12 wt %; aluminum (Al) in an amount of about 3.0 to 7.0 wt %; manganese (Mn) in an amount of about 0.5 wt % or less (not 0%); nickel (Ni) in an amount of about 0.5 wt % or less (not 0%); chromium (Cr) in an amount of about 0.75 wt % or less (not 0%); silicon (Si) in an amount of about 0.3 to 0.75 wt %; a combined amount of titanium (Ti) and vanadium (V) in an amount of about 0.25 to 0.7 wt %; and a balance being iron (Fe), all the wt % are based on the total weight of the ferritic steel.

## Claims

### Claim 1

A ferritic steel comprising:
carbon (C) in an amount of about 0.05 to 0.12 wt %;
aluminum (Al) in an amount of about 3.0 to 7.0 wt %;
manganese (Mn) in an amount of about 0.5 wt % or less (not 0 wt %);
nickel (Ni) in an amount of about 0.5 wt % or less (not 0 wt %);
chromium (Cr) in an amount of about 0.75 wt % or less (not 0 wt %);
silicon (Si) in an amount of about 0.3 to 0.75 wt %;
a combined amount of titanium (Ti) and vanadium (V) in an amount of about 0.25 to 0.7 wt %; and
a balance being iron (Fe),
all the wt % are based on the total weight of the ferritic steel.

### Claim 2 (depends on 1)

The ferritic steel of claim 1, further comprising,
Niobium (Nb) in an amount of about 0.02 wt % or less;
Phosphorus (P) in an amount of about 0.1 wt % or less;
Sulfur (S) in an amount of about 0.05 wt % or less;
Nitrogen (N) in an amount of about 0.01 wt % or less, or
a combination thereof.

### Claim 3 (depends on 1)

The ferritic steel of claim 1, wherein the ferritic steel has yield strength of about 500 Mpa or greater.

### Claim 4 (depends on 3)

The ferritic steel of claim 3, wherein the ferritic steel has yield strength of about 570 Mpa or greater.

### Claim 5 (depends on 1)

The ferritic steel of claim 1, wherein the ferritic steel has tensile strength of about 540 Mpa or greater.

### Claim 6 (depends on 5)

The ferritic steel of claim 5, wherein the ferritic steel has tensile strength of about 611 Mpa or greater.

### Claim 7 (depends on 1)

The ferritic steel of claim 1, wherein the ferritic steel has an elongation of about 10% or greater.

### Claim 8 (depends on 1)

The ferritic steel of claim 1, wherein the ferritic steel has a density of about 7.0 to 7.5 g/cm3.

### Claim 9 (depends on 1)

The ferritic steel of claim 1, wherein in the ferritic steel, a fraction of formed κ-carbide is less than about 1%.

### Claim 10 (depends on 1)

The ferritic steel of claim 1, consisting essentially of:
carbon (C) in an amount of about 0.05 to 0.12 wt %;
aluminum (Al) in an amount of about 3.0 to 7.0 wt %;
manganese (Mn) in an amount of about 0.5 wt % or less (not 0 wt %);
nickel (Ni) in an amount of about 0.5 wt % or less (not 0 wt %);
chromium (Cr) in an amount of about 0.75 wt % or less (not 0 wt %);
silicon (Si) in an amount of about 0.3 to 0.75 wt %;
a combined amount of titanium (Ti) and vanadium (V) in an amount of about 0.25 to 0.7 wt %; and
a balance being iron (Fe),
all the wt % are based on the total weight of the ferritic steel.

### Claim 11 (depends on 1)

The ferritic steel of claim 1, consisting of:
carbon (C) in an amount of about 0.05 to 0.12 wt %;
aluminum (Al) in an amount of about 3.0 to 7.0 wt %;
manganese (Mn) in an amount of about 0.5 wt % or less (not 0%);
nickel (Ni) in an amount of about 0.5 wt % or less (not 0%);
chromium (Cr) in an amount of about 0.75 wt % or less (not 0%);
silicon (Si) in an amount of about 0.3 to 0.75 wt %;
a combined amount of titanium (Ti) and vanadium (V) in an amount of about 0.25 to 0.7 wt %; and
a balance being iron (Fe),
all the wt % are based on the total weight of the ferritic steel.

### Claim 12 (depends on 1)

The ferritic steel of claim 1, consisting essentially of:
carbon (C) in an amount of about 0.05 to 0.12 wt %;
aluminum (Al) in an amount of about 3.0 to 7.0 wt %;
manganese (Mn) in an amount of about 0.5 wt % or less (not 0%);
nickel (Ni) in an amount of about 0.5 wt % or less (not 0%);
chromium (Cr) in an amount of about 0.75 wt % or less (not 0%);
silicon (Si) in an amount of about 0.3 to 0.75 wt %;
a combined amount of titanium (Ti) and vanadium (V) in an amount of about 0.25 to 0.7 wt %;
niobium (Nb) in an amount of about 0.02 wt % or less, phosphorus (P) in an amount of about 0.1 wt % or less, sulfur (S) in an amount of about 0.05 wt % or less, nitrogen (N) in an amount of about 0.01 wt % or less, or a combination thereof; and
a balance being iron (Fe),
all the wt % are based on the total weight of the ferritic steel.

### Claim 13 (depends on 1)

A vehicle comprising a ferritic steel of claim 1.