Method for producing a hot-formed and quench-hardened motor vehicle component formed by internal high-pressure forming

Patent metadata

Field	Value
Publication number	US-10443109-B2
Application number	US-201615059556-A
Country	US
Kind code	B2
Filing date	Mar 3, 2016
Priority date	Mar 6, 2015
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

The present invention relates to a method for producing a hot-formed and quench-hardened tubular motor vehicle component (7) by way of internal high-pressure forming, a metallic starting material being at least partially heated to a heating temperature, in particular to a temperature above Ac3, being subjected to internal high-pressure forming in the hot state, and subsequently being quenched, preferably quench-hardened, wherein the internal high-pressure forming is performed as high-speed forming in a time of between 1 and 30 seconds, and the still-hot, formed motor vehicle component (7) is transferred into at least one separate quenching tool (5, 10) and is in particular quench-hardened, the motor vehicle component (7) being braced in a fixed position in the quenching tool (5, 10) and the cycle time of the quenching tool (5, 10) corresponding to the cycle time of the internal high-pressure forming.

First claim

The invention claimed is:

1. A method for producing a hot-formed and quench-hardened tubular motor vehicle pillar by way of internal high-pressure forming, a metallic starting material being at least partially heated to a heating temperature, in particular to a temperature above Ac3, being subjected to internal high-pressure forming in the hot state, and subsequently being quench-hardened, wherein the internal high-pressure forming is performed as high-speed forming during a time of between 1 and 30 seconds, and the still-hot, formed motor vehicle pillar is transferred into at least one separate quenching tool and is quench-hardened, the motor vehicle pillar being braced in a fixed position in the quenching tool and the cycle time of the quenching tool corresponding to the cycle time of the internal high-pressure forming, the method further comprising the following steps,
providing two sheet-metal blanks, composed in particular of a pre-coated, hardenable steel alloy,
pre-bending at least one sheet-metal blank at a longitudinal edge such that in each case one longitudinal edge of one sheet metal blank is placed in butting contact with the longitudinal edge of the second sheet-metal blank, and a closed hollow profile is provided,
thermally joining the longitudinal edges that are in butting contact with one another, in particular by longitudinal seam welding, and
performing internal high-pressure forming of the hollow profile.

2. The method as claimed in claim 1 , wherein the motor vehicle pillar is quenched in two successive stages, and for this purpose, is transferred initially into a first quenching tool and subsequently into a second quenching tool, each quenching tool operating with the cycle time of the internal high-pressure forming.

3. The method as claimed in claim 1 , wherein the internal high-pressure forming is performed during a time of between 2 and 15 seconds.

4. The method as claimed in claim 1 , wherein the quenching is performed in a dip bath, and/or wherein the quenching is performed by way of spray cooling and/or injection cooling.

5. The method as claimed in claim 1 , wherein a positive fixing in position in each quenching tool is performed by way of a holding device, the geometric dimension of the holding device having an undersize in relation to the pillar dimension before the quenching process.

6. The method as claimed in claim 1 , wherein an internal high-pressure forming tool is cooled and heated, the temperature in the component being set to between martensite start temperature and Ac3.

7. The method as claimed in claim 1 , wherein a means for fixing in position is in the form of readjustable clamping jaws, and, during the quenching process, the clamping jaws are readjusted in accordance with the shrinkage of the motor vehicle pillar.

8. The method as claimed in claim 1 , wherein nozzles of a spray cooling means and/or injection cooling means perform rotating and/or pulsed spraying, such that the motor vehicle pillar is cooled homogeneously.

9. The method as claimed in claim 1 , wherein the motor vehicle pillar is produced.

10. The method as claimed in claim 1 , wherein an expected shrinkage curve of the motor vehicle pillar is calculated or determined experimentally, and clamping jaws are readjusted in a manner dependent on the shrinkage curve.

11. The method as claimed in claim 1 , wherein linear or punctiform contact against the surface of the produced motor vehicle pillar is generated by way of the clamping jaws.

12. The method as claimed in claim 1 , wherein a segmented internal high-pressure forming tool with multiple mold segments is used for the hot-forming process, and mold segments are slidingly feedable in particular in a longitudinal direction of the motor vehicle component.

13. The method as claimed in claim 1 , wherein the motor vehicle pillar is temperature-controlled during the internal high-pressure forming such that, after removal from an internal high-pressure forming tool, said motor vehicle pillar has a component temperature which, in the quenching tool, effects complete quench hardening by microstructure transformation.

14. The method as claimed in claim 1 , wherein the hollow profile is austenized before the internal high-pressure forming, and the pre-coating is fully alloyed.

15. The method as claimed in claim 14 , wherein the internal high-pressure forming is performed in the hot state of the hollow profile, and the component that has been formed by internal high-pressure forming is quench-hardened.

16. The method as claimed in claim 1 , wherein, on the side situated opposite the longitudinally seam-welded side, there is formed a flange region; particular, in each case one side of the sheet-metal blank is formed as a flange, which flanges overlap in the flange region.

17. The method as claimed in claim 16 , wherein, during the internal high-pressure forming, an enlargement of the cross section at least in sections takes place, with a shortening of at least one flange and/or, by way of ironing of the material, with a reduction in the wall thickness (W).

Assignees

• Benteler Automobiltechnik Gmbh
• Bentler Automobiltechnik GmbH

Inventors

• Gomez Rafael Garcia

Classifications

• C21D8/10

  during manufacturing of tubular bodies · CPC title

• C21D8/00

  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) · CPC title

• C21D1/18

  Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62) · CPC title

• B21D26/033

  Deforming tubular bodies (corrugating tubes by applying fluid pressure B21D15/03, B21D15/10) · CPC title

• B23K26/262

  of longitudinal seams of tubes · CPC title