Method for producing structural components and chassis components by hot forming, and heating station

Patent metadata

Field	Value
Publication number	US-9616488-B2
Application number	US-201214345153-A
Country	US
Kind code	B2
Filing date	Sep 10, 2012
Priority date	Sep 16, 2011
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

In a method for producing in particular structural components or chassis components for a motor vehicle by hot or semi-hot forming, a sheet metal blank is heated in a heating station at least in a first region from a starting temperature to a target temperature, and then the warm blank is transferred to a cooled pressing tool and is formed and press-hardened. The heating station includes at least one burner zone which includes at least one burner, in which zone the sheet metal blank is heated from the starting temperature to the target temperature, and at least one burner is operated with a combustion gas and an oxygen-containing gas and the sheet metal blank comes into direct contact with the burner flame.

First claim

What is claimed is:

1. A method for producing structural or chassis components for a motor vehicle by hot or warm forming, comprising:
providing a heating station comprising at least one burner zone, said at least one burner zone comprising at least one burner;
operating the at least one burner with a combustible gas and an oxygen containing gas to thereby generate a burner flame;
heating at least a first region of a sheet metal blank in the at least one burner zone from a starting temperature to a target temperature by bringing the sheet metal blank into direct contact with the burner flame generated by the burner;
heating an aluminum silicone pre-coated sheet metal blank in the heating station to a temperature smaller than Ac3 until pre-alloyed; and
heating the sheet metal blank in a furnace arranged downstream of the heating station to a temperature greater than Ac3 until completely austenized and alloyed through;
transferring the heated sheet metal blank into a cooled pressing tool; and
forming and press hardening the sheet metal blank in the cooled pressing tool to a finished component;
wherein during the heating in the heating station at the same time at least a partial alloy layer is formed on the surface of the sheet metal blank, thereby an aluminum silicone layer transforms from inside to outside into an intermetallic iron aluminum silicone layer due to diffusion process,
wherein an oxygen content of the oxygen-containing gas is greater than 90%, and wherein oxygen atoms not reacted during the combustion counteract a hydrogen embrittling in a heat influence zone, the hydrogen embrittling counteracted by a temperature profile with a heating rate of greater than 70K/s.

2. The method of claim 1 , wherein the target temperature causes a complete austenization of the first region of the sheet metal blank.

3. The method of claim 1 , further comprising heating a second region of the sheet metal blank to a temperature below Ac3, to thereby avoid a complete austenization of a basic material of the sheet metal blank in the second region and to enable a sufficient forming of the sheet metal blank in the cooled pressing tool, wherein a bainitic or ferritic microstructure and/or a mixed microstructure forms in the second region of the finished component.

4. The method of claim 1 , wherein the heating to the target temperature in the heating station is influenced via an orientation of a nozzle of the at least one burner and/or a distance of the nozzle to the sheet metal blank.

5. The method of the claim 1 , wherein the first region is heated to the target temperature with a rate of greater than 90K/s.

6. The method of claim 1 , wherein the first region is heated in the heating station to less than Ac3 of a starting material of the sheet metal blank and for complete austenization and homogenization of a microstructure, the sheet metal blank is subsequently heated in a furnace to a temperature above Ac3 and is held at the temperature above Ac3 for a period of time of less than 90 s.

7. The method of the claim 1 , wherein the heating rate occurs in a temperature range between 600 and 800° C.

8. The method of claim 1 , wherein the structural or chassis component has a ductility which is higher by 5% with same strength, compared to a component of same construction which was heated over 4 minutes in a conventional continuous furnace and completely austenized.

9. The method of claim 1 , wherein the structural or chassis component has a ductility which is higher by at least 10% with same strength, compared to a component of same construction which was heated over 4 minutes in a conventional continuous furnace and completely austenized.

Assignees

• Pellmann Markus
• Stelzer Frank
• Lenze Franz-Josef
• Benteler Automobiltechnik Gmbh

Inventors

• Pellmann Markus
• Stelzer Frank
• Lenze Franz-Josef

Classifications

• C21D9/46

  for sheet metals · CPC title

• F27B9/36

  Arrangements of heating devices · CPC title

• F27B9/26

  on or in trucks, sleds, or containers · CPC title

• F27B9/24

  being carried by a conveyor · CPC title

• F27D5/0006

  Composite supporting structures · CPC title