Method for forming a steel sheet part

Patent metadata

Field	Value
Publication number	US-10227673-B2
Application number	US-201615236810-A
Country	US
Kind code	B2
Filing date	Aug 15, 2016
Priority date	Dec 17, 2012
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

A method for creating a formed steel part from a steel sheet is provided. The steel sheet is heated to austenitization temperature. The steel sheet is formed with simultaneous cooling-down. A manganese-rich surface layer of the formed steel sheet is removed.

First claim

What is claimed is:

1. A method for creating a formed steel part from a steel sheet, comprising:
heating the steel sheet to austenitization temperature;
forming the steel sheet with simultaneous cooling-down; and
removing a manganese-rich surface layer of the formed steel sheet.

2. The method of claim 1 , wherein the steel sheet includes a steel substrate layer and a corrosion protection layer containing zinc and manganese.

3. The method of claim 2 , further comprising electrogalvanically applying the corrosion protection layer to the steel substrate layer prior to heating the steel sheet to austenitization temperature, the corrosion protection layer having a manganese component of at least 5% by weight.

4. The method of claim 2 , wherein the manganese component of the corrosion protection layer is at least 8% by weight.

5. The method of claim 2 , wherein the manganese component of the corrosion protection layer maximally amounts to 25% by weight.

6. The method of claim 2 , wherein the heating the steel sheet further comprises:
forming a second corrosion protection layer on a boundary between the steel substrate layer and a manganese-depleted layer of the corrosion protection layer; and
forming the manganese-rich surface layer along the manganese-depleted layer such that an exterior surface of the steel sheet consists of the manganese-rich surface layer.

7. The method of claim 6 , wherein the second corrosion protection layer comprises a zinc-iron alloy layer between the steel substrate layer and the manganese-depleted layer.

8. The method of claim 7 , wherein the removing the manganese-rich surface layer of the formed steel sheet further comprises removing the manganese-rich surface layer of the corrosion protection layer such that an exposed surface of the formed steel sheet consists of the manganese-depleted layer.

9. The method of claim 1 , wherein forming the steel sheet with simultaneous cooling-down further comprises press-hardening the steel sheet into a formed part with the simultaneous cooling-down.

10. The method of claim 2 , wherein the removing the manganese-rich surface layer of the formed steel sheet further comprises removing the manganese-rich surface layer such that the manganese contained in the corrosion protection layer electrogalvanically deposited onto the steel substrate layer has been substantially removed.

11. A method for creating a formed steel part from a steel sheet, comprising:
electrogalvanically applying a corrosion protection layer to a steel substrate layer to form the steel sheet, the corrosion protection layer having a manganese component of at least 5% by weight;
heating the steel sheet to austenitization temperature to form a manganese-rich surface layer;
forming the steel sheet with simultaneous cooling-down; and
removing the manganese-rich surface layer of the formed steel sheet.

12. The method of claim 11 , wherein the heating the steel sheet further comprises:
forming a second corrosion protection layer on a boundary between the steel substrate layer and a manganese-depleted layer of the corrosion protection layer; and
forming the manganese-rich surface layer along the manganese-depleted layer such that an exterior surface of the steel sheet consists of the manganese-rich surface layer.

13. The method of claim 12 , wherein the second corrosion protection layer comprises a zinc-iron alloy layer between the steel substrate layer and the manganese-depleted layer.

14. The method of claim 13 , wherein the removing the manganese-rich surface layer of the formed steel sheet further comprises removing the manganese-rich surface layer of the corrosion protection layer such that an exposed surface of the formed steel sheet consists of the manganese-depleted layer.

15. The method of claim 11 , wherein the heating the steel sheet further comprises:
forming a second corrosion protection layer on a boundary between the steel substrate layer and the corrosion protection layer,
wherein the second corrosion protection layer comprises a zinc-iron alloy layer between the steel substrate layer and the corrosion protection layer.

16. A method for creating a formed steel part from a steel sheet, consisting of:
electrogalvanically applying a corrosion protection layer to a steel substrate layer to form the steel sheet, the corrosion protection layer having a manganese component of at least 5% by weight;
heating the steel sheet to austenitization temperature to form a manganese-rich surface layer and a manganese-depleted layer under the manganese-rich surface layer;
forming the steel sheet with simultaneous cooling-down; and
removing the manganese-rich surface layer of the formed steel sheet such that an exposed surface of the formed steel sheet consists of the manganese-depleted layer.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Baumgart Hartmut
• Sanders Ronald

Classifications

• C25D3/565

  containing more than 50% by weight of zinc · CPC title

• C25D5/50

  by heat-treatment · CPC title

• C21D8/1277

  involving a particular surface treatment (C21D8/1294 takes precedence) · CPC title

• Y10T428/12799

  Next to Fe-base component [e.g., galvanized] · CPC title

• C21D1/673

  for die quenching · CPC title