# US 11,078,551 B2 · Three-dimensional cooling type hot-stamping method and system and vehicle structural member manufactured by the same

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- Number: US 11,078,551 B2
- Document ID: US11078551B2
- Status: Granted
- Kind: B2
- Application number: 15/808,612
- Filed: 2017-11-09
- Published: 2018-06-21
- Granted: 2021-08-03
- Earliest claimed: 2016-12-15
- Assignees: Hyundai Motor Company; Kia Motors Corporation; Sungwoo Hitech Co., Ltd.
- Applicants: Hyundai Motor Company; Kia Motors Corporation; Sungwoo Hitech Co., Ltd.
- Inventors: Hyun-Gyung Kim; Dong-Eun Cha; Jin-Young Yoon; Dae-Jung Kim
- Web page: https://patentgrep.com/patent/US11078551B2

## CPC

- C21D 1/673: for die quenching
- B21D 22/022: {by heating the blank or stamping associated with heat treatment (C21D takes precedence)}
- C21D 9/46: for sheet metals
- C21D 11/005: {for cooling}
- 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)
- 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)

## Abstract

A hot-stamping method may include a three-dimensional cooling mode in which, when a closed-section product placed in an upper mold and a lower mold that are coupled each other is heat-treated under control of a controller, an external cooling water direct spraying operation of directly spraying cooling water onto an external portion of the closed-section product is performed and, simultaneously, an internal cooling water direct spraying operation of directly spraying cooling water into an internal of the closed-section product is performed.

## Claims

### Claim 1

A hot-stamping method, comprising:
performing a three-dimensional cooling mode in which, a closed-section product disposed in an upper mold and a lower mold that are coupled to each other is heat-treated under control of a controller,
wherein the three-dimensional cooling mode includes:
coupling the upper mold with the lower mold after a product to be formed has been disposed on a die of the lower mold, and stamping the product using the upper mold and manufacturing the product into the closed-section product;
performing an external cooling water direct spraying operation of directly spraying a cooling water onto an external portion of the closed-section product by an upper-mold direct spray device disposed in the upper mold after the upper mold and the lower mold have been coupled with each other;
performing the external cooling water direct spraying operation of directly spraying the cooling water onto the external portion of the closed-section product by a lower-mold direct spray device disposed in the lower mold after the upper mold and the lower mold have been coupled with each other;
performing an internal cooling water direct spraying operation of directly spraying the cooling water into an internal volume of the closed-section product by one of a first closed-section cooling water spray device disposed on a one side of the upper and lower molds and a second closed-section cooling water spray device provided on an opposite side thereof, after the upper mold and the lower mold have been coupled with each other; and
continuing the external cooling water direct spraying operation and the internal cooling water direct spraying operation during a time of a heat treatment,
wherein the internal cooling water direct spraying operation forms a partial closed cooling water circulation flow in the closed-section product, wherein the partial closed cooling water circulation flow is formed such that the cooling water is drawn from the first closed-section cooling water spray device and flows along the internal volume of the closed-section product, and when the cooling water reaches the second closed-section cooling water spray device, a unblocked cooling water flow and a blocked cooling water flow are formed by the second closed-section cooling water spray device, and the unblocked cooling water flow is discharged through the second closed-section cooling water spray device while the blocked cooling water flow remains in the closed-section product, and
wherein the blocked cooling water flow of the cooling water that is blocked by valve connectors of a lower cooling water block of the second closed-section cooling water spray device returns from an opposite side end portion of the closed-section product to a one side end portion of the closed-section product, and the blocked cooling water flow remains, rather than being discharged externally, in closed-sections of the closed-section product because of cooling water that is drawn into a lower cooling water block of the first closed-section cooling water spray device, and
wherein a valve connector of an upper cooling water block of the second closed-section cooling water spray device is turned on in order for the unblocked cooling water flow to be discharged through the second closed-section cooling water spray device, the upper cooling water block being located above the lower cooling water block.

### Claim 2 (depends on 1)

The hot-stamping method of claim 1, wherein performing the internal cooling water direct spraying operation for the internal volume of the closed-section product is in a simultaneous, sequential, or circulating manner in relation to the external cooling water direct spraying operation.

### Claim 3 (depends on 1)

The hot-stamping method of claim 1, wherein the time of the heat treatment is fifteen seconds.

### Claim 4 (depends on 1)

The hot-stamping method of claim 1, wherein the upper-mold direct spray device is disposed over the closed-section product and directly sprays the cooling water toward the external portion of the closed-section product, and the lower-mold direct spray device is disposed below the closed-section product and directly sprays the cooling water toward the external portion of the closed-section product.

### Claim 5 (depends on 1)

The hot-stamping method of claim 1, wherein the internal cooling water direct spray operation forms a closed cooling water circulation flow in the closed-section product, wherein the closed cooling water circulation flow is formed such that the cooling water is drawn from the first closed-section cooling water spray device, flows along the internal volume of the closed-section product, is blocked by the second closed-section cooling water spray device, flows into a reverse direction along the internal volume of the closed-section product, and is discharged through the first closed-section cooling water spray device.

### Claim 6 (depends on 1)

The hot-stamping method of claim 1, wherein the product to be formed is heated at 950° C. for six minutes and then placed on the die of the lower mold.

### Claim 7 (depends on 1)

A vehicle structural member manufactured as a bumper beam by the hot-stamping method according to claim 1.