# US 2012/0073708 A1 · Method of shaping and hardening a sheet steel blank

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- Number: US 2012/0073708 A1
- Document ID: US20120073708A1
- Status: Published application
- Kind: A1
- Application number: 13/261,035
- Filed: 2010-06-09
- Published: 2012-03-29
- Earliest claimed: 2009-06-15
- Assignees: Gestamp Hardtech AB
- Inventors: Jan Krispinsson
- Web page: https://patentgrep.com/patent/US20120073708A1

## CPC

- C21D 1/673: for die quenching
- B21D 22/02: Stamping using rigid devices or tools
- B21D 37/16: Heating or cooling
- C21D 8/00: Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment (hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D1/02)
- C21D 9/505: {Cooling thereof}
- C21D 8/02: during manufacturing of plates or strips (C21D8/12 takes precedence)
- 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

The properties of products manufactured by press hardening from composite blanks, referred to as tailor-welded blanks (TWB), are improved by cooling the weld at a reduced cooling rate during the hardening of the formed product so that a narrow, soft area is formed alongside the weld.

## Claims

### Claim 1

Method of shaping and hardening a sheet-steel blank, composed of separate sheets welded together, to give a product by heating the blank to the austenitising range and hot-stamping the blank in a cooled tool pair, then hardening the formed product while it remains in the tool pair,
characterised in that the weld between two sheets is cooled at a reduced cooling rate in relation to the areas on either side of the weld so that a narrow, soft area is formed along the weld.

### Claim 2 (depends on 1)

Method according to claim 1, characterised in that the cooling rate is reduced by maintaining a gap between the tool pair and the finished product.