Method of manufacturing a hot-stamped part

Patent metadata

Field	Value
Publication number	US-11931786-B2
Application number	US-202318096442-A
Country	US
Kind code	B2
Filing date	Jan 12, 2023
Priority date	Dec 20, 2019
Publication date	Mar 19, 2024
Grant date	Mar 19, 2024

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;
soaking the blank at a temperature of Ac3 to 1,000° C. as the blank passes through the soaking sections;
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, wherein, in the step heating of the blank, a temperature condition in the heating furnace satisfies formula:
0<(Tg—Ti)/Lt<0.025° C./mm

wherein 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 same temperature range in the heating furnace,
wherein the blank includes a tailor rolled blank (TRB) having partially different thicknesses obtained by rolling a plate material having a uniform thickness.

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 greater than a temperature of other sections for the step heating of the blank.

4. The method of claim 1 , wherein in the cooling of the formed molded body, the blank is held in the press mold for about 3 seconds to about 20 seconds.

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

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 , wherein in the transferring of 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

• B21D22/022 Primary

  by heating the blank or stamping associated with heat treatment (C21D takes precedence) · CPC title

• C22C38/001

  containing N · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title

• C22C38/02

  containing silicon · CPC title