# US 11,027,325 B2 · Hot-formed metal sheet and method of producing an opening in such a metal sheet

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- Number: US 11,027,325 B2
- Document ID: US11027325B2
- Status: Granted
- Kind: B2
- Application number: 15/851,297
- Filed: 2017-12-21
- Published: 2018-06-28
- Granted: 2021-06-08
- Earliest claimed: 2016-12-22
- Assignees: Benteler Automobiltechnik GmbH
- Applicants: Benteler Automobiltechnik GmbH
- Inventors: Markus Kettler; Georg Frost; Frank Rabe; Karsten Bake
- Web page: https://patentgrep.com/patent/US11027325B2

## CPC

- B21D 28/26: in sheets or flat parts
- B21D 28/16: Shoulder or burr prevention {, e.g. fine-blanking}
- B21D 22/208: {by heating the blank or deep-drawing associated with heat treatment (C21D takes precedence)}
- B21D 53/88: other parts for vehicles, e.g. cowlings, mudguards
- C21D 1/673: for die quenching
- C21D 2261/00: Machining or cutting being involved
- 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-formed metal sheet has a tensile strength Rm>1300 megapascal (MPa) and includes an opening which is produced by high-speed punching at a speed of a punch of more than 6 m/s in the absence of a counter holder of a contour matching a contour of the punch, with a smooth cut proportion of the cutting surface of the opening amounting to more than 50%.

## Claims

### Claim 1

A method, comprising:
hot forming and press hardening a metal sheet in a press-hardening tool to a tensile strength of Rm >1300 megapascal (MPa); and
producing an opening with closed cutting line in the hot formed and press hardened metal sheet at the tensile strength Rm solely by high-speed punching the metal sheet in a single-step process with a punch at a speed of the punch of more than 6 m/s, sufficient to cause a momentary temperature rise in immediate proximity of the opening to at least minimize strain hardening and wherein the producing step is performed without the use of a counter holder.

### Claim 2 (depends on 1)

The method of claim 1, wherein the speed of the punch is less than 100 m/s and greater than 10 m/s.

### Claim 3 (depends on 1)

The method of claim 1, wherein the speed of the punch is less than 100 m/s and greater than 20 m/s.

### Claim 4 (depends on 1)

The method of claim 1, further comprising mounting the punch to a robotic arm for movement of the punch into a work position in relation to the metal sheet.

### Claim 5 (depends on 4)

The method of claim 4, further comprising securing the metal sheet to the robotic arm or to a further robotic arm in relation to the punch in the work position.