Motor vehicle component and a method of manufacturing thereof

Patent metadata

Field	Value
Publication number	US-11519047-B2
Application number	US-201715592545-A
Country	US
Kind code	B2
Filing date	May 11, 2017
Priority date	May 12, 2016
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A motor vehicle component and a method of manufacturing thereof is disclosed having at least regionally high-strength and at the same time ductile properties, including providing a sheet metal blank composed of a hardenable steel alloy with at least 0.25% carbon fraction, at least partially heating the sheet metal blank to above austenitizing temperature, in less than 20 seconds, hot-forming and press-hardening the sheet metal blank, in the process, setting a tensile strength Rm of greater than 1800 MPa and an elongation at break A20 of greater than 6%.

First claim

The invention claimed is:

1. A method of manufacturing a motor vehicle component, the method comprising:
providing a sheet metal blank comprising a hardenable steel alloy with greater than 0.35% carbon fraction in weight;
heating the sheet metal blank at a heating rate greater than 100° C./s at least partially to above austenitizing temperature;
holding, during the heating, the sheet metal blank at the heating temperature;
transferring from the heating into a hot-forming and press-hardening tool; and
hot-forming and press-hardening the sheet metal blank in the hot forming and press-hardening tool to obtain the motor vehicle component having an elongation at break A20 of greater than 6%, wherein
the press-hardening is performed to obtain the motor vehicle component having a tensile strength Rm of greater than 1900 MPa, and
the heating, holding, and transferring are performed in less than 30 seconds.

2. The method of claim 1 , wherein said press-hardening is performed to obtain the motor vehicle component having the tensile strength Rm of greater than 2000 MPa.

3. The method of claim 1 , wherein said press-hardening is performed to obtain the motor vehicle component having an elongation at break A20 of greater than 8%.

4. The method of claim 1 , wherein the heating is performed in less than 10 seconds.

5. The method of claim 1 , wherein, in the heating, the holding time of the heated sheet metal blank at the heating temperature is less than 20 seconds.

6. The method of claim 5 , wherein the transferring time from the heating into the hot-forming and press-hardening tool is in less than 10 seconds.

7. The method of claim 1 , wherein a martensitic material microstructure with 5.0% to 20.0% bainite in weight is achieved in the motor vehicle component during the press hardening.

8. The method of claim 1 , wherein the heating is contact heating.

9. The method of claim 1 , wherein the heating comprises heating the sheet metal blank completely.

10. The method of claim 9 , wherein the press-hardening comprises hardening the motor vehicle component only in regions where anticipated loads are high.

11. The method of claim 10 , further comprising at least partial thermal after-treatment of the motor vehicle component.

12. The method of claim 1 , further comprising preforming the sheet metal blank before the heating.

13. The method of claim 12 , wherein the sheet metal blank is multi-ply having
a centrally located ply comprising the hardenable steel alloy, and
two outer plies comprising a stainless steel alloy.

14. The method of claim 1 , wherein said press-hardening is performed to obtain the motor vehicle component having an elongation at break A20 of greater than 10%.

15. The method of claim 1 , wherein, in said heating,
a first region of the sheet metal blank is heated to a temperature higher than the austenitizing temperature, and
a second region of the sheet metal blank is not heated, or is heated to a temperature lower than the austenitizing temperature.

16. A method of manufacturing a motor vehicle component, the method comprising:
providing a sheet metal blank comprising a hardenable steel alloy with at least 0.25% carbon fraction in weight;
heating the sheet metal blank at least partially to above austenitizing temperature;
hot-forming and press-hardening the sheet metal blank to obtain the motor vehicle component having an elongation at break A20 of greater than 6%; and
edge decarburizing the motor vehicle component after it is manufactured.

17. The method of claim 16 , wherein the edge decarburizing is performed in an edge zone at 5 to 150 μm, measured from a surface of the motor vehicle component.

18. A motor vehicle component manufactured using the method of claim 1 , wherein the motor vehicle component has the tensile strength Rm of greater than 1900 MPa and the elongation at break A20 of greater than 6%, and the motor vehicle component comprises the hardenable steel alloy having the carbon fraction of greater than 0.35% in weight and has a substantially martensitic material microstructure with a bainite fraction of 5.0% to 20.0% in weight.

Assignees

• Benteler Automobiltechnik Gmbh

Inventors

• Holzweissig Martin
• Frost Georg
• Erhardt Ruediger

Classifications

• 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

• C21D8/0257

  with diffusion of elements, e.g. decarburising, nitriding · CPC title

• C22C38/02

  containing silicon · CPC title

• C22C38/04

  containing manganese · CPC title

• C21D2211/002

  Bainite · CPC title