Hot-stamped part and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-11583909-B2
Application number	US-202017109981-A
Country	US
Kind code	B2
Filing date	Dec 2, 2020
Priority date	Dec 20, 2019
Publication date	Feb 21, 2023
Grant date	Feb 21, 2023

Abstract

A method of manufacturing a hot-stamped part includes: inserting a blank into a heating furnace including a plurality of sections with different temperature ranges; step heating the blank in multiple stages; and soaking the blank at a temperature of about Ac3 to about 1,000° C., wherein in the step of heating the blank, a temperature condition in the heating furnace satisfies the following equation: 0<(Tg−Ti)/Lt<0.025° C./mm, where Tg denotes a soaking temperature (° C.), Ti denotes an initial temperature (° C.) of the heating furnace, and Lt denotes a length (mm) of step heating sections.

First claim

What is claimed is:

1. A method of manufacturing a part to be hot-stamped, the method comprising:
inserting a blank into a heating furnace wherein the heating furnace includes heating sections and soaking sections;
step heating the blank as the blank passes through the heating sections; and
soaking the blank at a temperature of Ac3 to 1,000° C. as the blank passes through the soaking sections;
wherein, in the step of heating the blank, a temperature condition in the heating furnace satisfies a formula:
0<( Tg−Ti )/ Lt< 0.025° C./mm

where Tg denotes a soaking temperature (° C.), Ti denotes an initial temperature (° C.) of the heating furnace, and Lt denotes a total length (mm) of the heating sections,
wherein the soaking is performed in the soaking sections having the same temperature range in the heating furnace.

2. The method of claim 1 , wherein among the plurality of sections, a ratio of a total length of the heating sections to a total length of the soaking sections is 1:1 to 4:1.

3. The method of claim 2 , wherein among the plurality of sections, a temperature of a section for soaking the blank is higher than a temperature of other sections for step heating the blank.

4. The method of claim 1 , wherein the blank and an additional blank have different thicknesses and are simultaneously transferred into the heating furnace.

5. The method of claim 1 , wherein the blank includes a first portion having a first thickness and a second portion having a second thickness, the second thickness being different from the first thickness.

6. The method of claim 1 , wherein a difference in temperature between two adjacent sections among the plurality of sections for step heating the blank is greater than 0° C. and less than or equal to 100° C.

7. The method of claim 1 , wherein the blank remains in the heating furnace for 180 seconds to 360 seconds.

8. The method of claim 1 , further comprising, after soaking of the blank, carrying out steps of:
transferring the soaked blank from the heating furnace to a press mold;
forming a molded body by hot-stamping the transferred blank; and
cooling the formed molded body.

9. The method of claim 8 , wherein in transferring the soaked blank from the heating furnace to the press mold, the soaked blank is air-cooled for 10 seconds to 15 seconds.

Assignees

• Hyundai Steel Co

Inventors

• Kong Je Youl

Classifications

• C21D8/00 Primary

  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

• C22C38/32

  with boron · CPC title

• C21D2211/005

  Ferrite · CPC title

• C22C38/28

  with titanium or zirconium · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title