# US 12,180,573 B2 · Hot-stamping formed body

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- Number: US 12,180,573 B2
- Document ID: US12180573B2
- Status: Granted
- Kind: B2
- Application number: 17/431,324
- Filed: 2020-03-19
- Published: 2022-04-21
- Granted: 2024-12-31
- Earliest claimed: 2019-03-20
- Assignees: Nippon Steel Corporation
- Applicants: Nippon Steel Corporation
- Inventors: Shingo Fujinaka; Yuri Toda; Daisuke Maeda
- Web page: https://patentgrep.com/patent/US12180573B2

## CPC

- C22C 38/58: with more than 1.5% by weight of manganese
- B21D 22/022: {by heating the blank or stamping associated with heat treatment (C21D takes precedence)}
- C21D 1/18: Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62)
- C21D 8/0426: {Hot rolling}
- C21D 8/0436: {Cold rolling}
- C21D 8/0473: {Final recrystallisation annealing}
- C21D 9/46: for sheet metals
- C22C 38/002: {containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60}
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- C22C 38/28: with titanium or zirconium
- C22C 38/32: with boron
- 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 8/0226: {Hot rolling}
- C21D 8/0236: {Cold rolling}
- C21D 8/0273: {Final recrystallisation annealing}
- C21D 2211/001: Austenite
- C22C 38/005: {containing rare earths, i.e. Sc, Y, Lanthanides}
- C22C 38/22: with molybdenum or tungsten
- C22C 38/24: with vanadium
- C22C 38/26: with niobium or tantalum
- C22C 38/30: with cobalt
- C22C 38/38: with more than 1.5% by weight of manganese
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- B21D: WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL (working or processing of wire B21F)
- 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

A hot-stamping formed body has a predetermined chemical composition, in which an average grain size of prior austenite grains in a microstructure is 5.0 μm or less, and an average Mn concentration at grain boundaries of the prior austenite grains is 1.0 mass % or less. The hot-stamping formed body may be provided with a plating layer on the surface thereof, or may have a softened region in a portion thereof.

## Claims

### Claim 1

A hot-stamping formed body comprising, as a chemical composition, by mass %:
C: 0.40% to 0.70%;
Si: 0.010% to 1.30%;
Mn: 0.40% to 3.00%;
sol. Al: 0.0010% to 0.500%;
Ti: 0.010% to 0.100%;
Cr: 0.010% to 0.80%;
B: 0.0005% to 0.0100%;
P: 0.100% or less;
S: 0.0100% or less;
N: 0.0100% or less;
Nb: 0% to 0.100%;
Mo: 0% to 1.00%;
V: 0% to 0.100%;
Ni: 0% to 0.50%;
REM: 0% to 0.0100%;
Mg: 0% to 0.0100%;
Ca: 0% to 0.0100%;
Co: 0% to 4.00%; and
a remainder consisting of Fe and impurities,
wherein an average grain size of prior austenite grains in a microstructure is 5.0 μm or less, and
an average Mn concentration at grain boundaries of the prior austenite grains is 1.0 mass % or less.

### Claim 2

A hot-stamping formed body comprising, as a chemical composition, by mass %:
C: 0.40% to 0.70%;
Si: 0.010% to 1.30%;
Mn: 0.40% to 3.00%;
sol. Al: 0.0010% to 0.500%;
Ti: 0.010% to 0.100%;
Cr: 0.010% to 0.80%;
B: 0.0005% to 0.0100%;
P: 0.100% or less;
S: 0.0100% or less;
N: 0.0100% or less;
Nb: 0% to 0.100%;
Mo: 0% to 1.00%;
V: 0% to 0.100%;
Ni: 0% to 0.50%;
REM: 0% to 0.0100%;
Mg: 0% to 0.0100%;
Ca: 0% to 0.0100%;
Co: 0% to 4.00%; and
a remainder comprising Fe and impurities,
wherein an average grain size of prior austenite grains in a microstructure is 5.0 μm or less, and
an average Mn concentration at grain boundaries of the prior austenite grains is 1.0 mass % or less.

### Claim 3 (depends on 1)

The hot-stamping formed body according to claim 1 comprising, as the chemical composition, by mass %, one or more elements selected from:
Nb: 0.010% to 0.100%;
Mo: 0.01% to 1.00%;
V: 0.001% to 0.100%;
Ni: 0.001% to 0.50%;
REM: 0.0010% to 0.0100%;
Mg: 0.0010% to 0.0100%;
Ca: 0.0010% to 0.0100%; and
Co: 0.10% to 4.00%.

### Claim 4 (depends on 1)

The hot-stamping formed body according to claim 1, further comprising:
a plating layer on a surface of the hot-stamping formed body.

### Claim 5 (depends on 1)

The hot-stamping formed body according to claim 1,
wherein a portion of the hot-stamping formed body has a softened region.

### Claim 6 (depends on 3)

The hot-stamping formed body according to claim 3, further comprising:
a plating layer on a surface of the hot-stamping formed body.

### Claim 7 (depends on 3)

The hot-stamping formed body according to claim 3,
wherein a portion of the hot-stamping formed body has a softened region.

### Claim 8 (depends on 4)

The hot-stamping formed body according to claim 4,
wherein a portion of the hot-stamping formed body has a softened region.