Method for laser heat treatment to improve formability of advanced high strength steels

Patent metadata

Field	Value
Publication number	US-9670560-B2
Application number	US-201314145034-A
Country	US
Kind code	B2
Filing date	Dec 31, 2013
Priority date	Sep 17, 2013
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

A method for laser heat treatment of high tensile steel is provided to improve for improving formability. The method includes performing a heat treatment by irradiating a surface of a high tensile steel blank that includes a martensite structure and a ferrite structure with a laser to decrease a fraction of the martensite structure and increase a fraction of the ferrite structure. In addition, the method includes slowly cooling the blank to temper or anneal the heat-treated blank and subjecting the cooled blank to cold press forming.

First claim

What is claimed is:

1. A method for laser heat treatment of steels, the method comprising:
performing a heat treatment by irradiating a surface of a high tensile steel blank that includes a martensite structure and a ferrite structure with a laser to decrease a fraction of the martensite structure and increase a fraction of the ferrite structure;
cooling the high tensile steel blank to temper or anneal the heat-treated blank; and
subjecting the cooled blank to cold press forming.

2. The method of claim 1 , wherein the laser is irradiated through a laser beam head which moves while being separated from the surface of the high tensile steel blank.

3. The method of claim 1 , wherein the high tensile steel is selected from a group consisting of: dual phase steel (DP), transformation induced plasticity steel (TRIP), ferrite-bainitic steel (FB), complex phase steel (CP), and martensitic steel (MS).

4. The method of claim 1 , wherein a temperature of the heat treatment is about 500° C. to 800° C.

5. The method of claim 1 , wherein a rate of the heat treatment is about 5 mm/s to 20 mm/s.

6. The method of claim 1 , wherein a rate of the cooling is about 20° C./s or less.

Assignees

• Hyundai Motor Co Ltd

Inventors

• Kim Kyung-Bo

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

• B23K26/0006

  taking account of the properties of the material involved (B23K26/32, B23K26/40 take precedence) · CPC title

• B23K2201/18

  Operations & Transport · mapped topic

• B23K2203/04

  Operations & Transport · mapped topic

• B23K26/0093

  combined with mechanical machining or metal-working covered by other subclasses than B23K · CPC title