# US 10,119,186 B2 · Maraging steel excellent in fatigue characteristics

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

- Number: US 10,119,186 B2
- Document ID: US10119186B2
- Status: Granted
- Kind: B2
- Application number: 14/450,453
- Filed: 2014-08-04
- Published: 2015-02-26
- Granted: 2018-11-06
- Earliest claimed: 2013-08-23
- Assignees: Daido Steel Co., Ltd.
- Applicants: Kenji Sugiyama; Shigeki Ueta
- Inventors: Kenji Sugiyama; Shigeki Ueta
- Web page: https://patentgrep.com/patent/US10119186B2

## CPC

- C22C 38/14: containing titanium or zirconium
- 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 38/06: containing aluminium
- C22C 38/08: containing nickel {(C22C38/105 takes precedence)}
- C22C 38/105: {containing Co and Ni}
- C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium
- C22C 38/16: containing copper
- C22C 38/28: with titanium or zirconium
- C22C 38/44: with molybdenum or tungsten
- C22C 38/50: with titanium or zirconium
- C22C 38/52: with cobalt
- C22C 38/54: with boron
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

Provided is a maraging steel excellent in fatigue characteristics, including, in terms of % by mass: C: ≤0.015%, Ni: from 12.0 to 20.0%, Mo: from 3.0 to 6.0%, Co: from 5.0 to 13.0%, Al: from 0.01 to 0.3%, Ti: from 0.2 to 2.0%, O: ≤0.0020%, N: ≤0.0020%, and Zr: from 0.001 to 0.02%, with the balance being Fe and unavoidable impurities.

## Claims

### Claim 1

A maraging steel, consisting of, in terms of % by mass:
C: ≤0.015%,
Ni: 12.0 to 20.0%,
Mo: 3.0 to 6.0%,
Co: 5.0 to 13.0%,
Al: 0.01 to 0.3%,
Ti: 0.2 to 2.0%,
O: ≤0.0020%,
N: 0.0005 to 0.0020%,
Zr: from 0.001 to 0.02%, and optionally one or more of:
B: from 0.0010 to 0.010%,
Mg: ≤0.003%, and
Ca: ≤0.003%
with the balance being Fe and unavoidable impurities,
wherein the maraging steel comprises at least one TiN or TiCN inclusion with ZrO2 present in a center part thereof.

### Claim 2 (depends on 1)

The maraging steel according to claim 1, the content of Zr being 0.001 to 0.008% by mass.

### Claim 3 (depends on 1)

A thin steel sheet having a thickness of 0.5 mm or less and consisting of the maraging steel according to claim 1.

### Claim 4

A maraging steel consisting of, in terms of % by mass:
C: ≤0.015%,
Ni: 12.0 to 20.0%,
Mo: 3.0 to 6.0%,
Co: 5.0 to 13.0%,
Al: 0.01 to 0.3%,
Ti: 0.2 to 2.0%,
O: ≤0.0020%,
N: 0.0005 to 0.0020%,
Zr: from 0.001 to 0.02%, and optionally one or more of:
B: from 0.0010 to 0.010%,
Mg: ≤0.003%, and
Ca: ≤0.003%
with the balance being Fe and unavoidable impurities,
wherein the maraging steel comprises at least one TiN or TiCN inclusion with ZrO2 present in a center part thereof and
the maraging steel has a fatigue characteristic, when tested according to the method of JIS Z 2273 (2010), of 107 repetitions or more.

### Claim 5 (depends on 4)

The maraging steel according to claim 4, the content of Zr being 0.001 to 0.008% by mass.

### Claim 6 (depends on 4)

A thin steel sheet having a thickness of 0.5 mm or less and consisting of the maraging steel according to claim 4.