Device and method for hot stamping

Patent metadata

Field	Value
Publication number	US-2016250677-A1
Application number	US-201615148235-A
Country	US
Kind code	A1
Filing date	May 6, 2016
Priority date	Jun 18, 2014
Publication date	Sep 1, 2016
Grant date	—

Abstract

A device for hot stamping includes a lower mold having a shape corresponding to a bottom of a product material. An upper mold has a shape corresponding to a top of the product material and presses the product material with the lower mold. A blank holder is disposed inside the upper mold and fixes a blank between the upper mold and the lower mold. A cam has a shape corresponding to a flange of the product material and forms the flange of the product material by moving up or down along an inner side of the blank holder.

First claim

What is claimed is:

1 . A method of hot stamping, comprising steps of:
fixing a blank between a lower mold and an upper mold of a device for hot stamping; pressing and forming the blank with the lower mold and the upper mold; rapidly cooling a portion of the blank, which is in contact with the lower mold and the upper mold and slowly cooling a flange of a product material, which is not in contact with the lower mold and the upper mold; and forming the flange by a cam.

2 . The method of claim 1 , wherein:
in the step of forming the flange by the cam, the flange is formed by the cam in an austenite region.

3 . The method of claim 2 , further comprising a step of:
phase transforming by rapidly cooling the blank under a martensite transformation end temperature (M f ) from the austenite region, wherein the phase transformation is performed without bainite and ferrite transformation reactions.

4 . The method of claim 3 , wherein:
the rapid cooling speed is 50° C./s to 150° C./s and a slow cooling speed is 5° C./s to 20° C./s.

5 . The method of claim 1 , wherein:
the blank includes Ni of 0.01 wt % to 0.03 wt %, Cr of 0.1 wt % to 0.5 wt %, Mo of 0.001 wt % to 0.012 wt % and further includes B of 0.001 wt % to 0.005 wt %, and a balance includes Fe and impurities inevitably included in steel.

6 . The method of claim 2 , wherein:
the blank includes Ni of 0.01 wt % to 0.03 wt %, Cr of 0.1 wt % to 0.5 wt %, Mo of 0.001 wt % to 0.012 wt % and further includes B of 0.001 wt % to 0.005 wt %, and a balance includes Fe and impurities inevitably included in steel.

7 . The method of claim 3 , wherein:
the blank includes Ni of 0.01 wt % to 0.03 wt %, Cr of 0.1 wt % to 0.5 wt %, Mo of 0.001 wt % to 0.012 wt % and further includes B of 0.001 wt % to 0.005 wt %, and a balance includes Fe and impurities inevitably included in steel.

8 . The method of claim 4 , wherein:
the blank includes Ni of 0.01 wt % to 0.03 wt %, Cr of 0.1 wt % to 0.5 wt %, Mo of 0.001 wt % to 0.012 wt % and further includes B of 0.001 wt % to 0.005 wt %, and a balance includes Fe and impurities inevitably included in steel.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Kong Ho Young

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

• C21D2211/001

  Austenite · CPC title

• B21D37/16

  Heating or cooling · CPC title

• C21D1/673

  for die quenching · CPC title

• C21D1/18

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