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Title:
METHOD FOR MANUFACTURING HOT-PRESSED HIGH STRENGTH STEEL MEMBER WITH LOW RESIDUAL STRESS
Document Type and Number:
Japanese Patent JP2006130519
Kind Code:
A
Abstract:

To provide a method for manufacturing a high strength steel member, which is manufactured by carrying out a post processing, such as trimming, piercing, after a hot press process, and has a tensile strength of 980 MPa or higher and a low residual stress.

The method for manufacturing the hot-pressed high strength steel member with low residual stress is carried out as follows. A steel plate is heated up to a temperature higher than the Ac3 transformation point and lower than 1,300°C, and then is hot-pressed at a temperature higher than the Ar3 transformation point plus 20°C, and is successively post-processed by trimming or piercing at a temperature higher than the Ar3 transformation point, and then is cooled. By these processes, the member having a tensile strength of 980 MPa or higher, a residual stress of 400 MPa or lower, and a martensite structure of 60% or more by an area fraction can be obtained.


Inventors:
Satou, Hiroaki
Akamatsu, Satoshi
Hayashi, Kunio
Senuma, Takehide
Application Number:
JP2004000320297
Publication Date:
May 25, 2006
Filing Date:
November 04, 2004
Export Citation:
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Assignee:
NIPPON STEEL CORP
International Classes:
B21D22/20; B21D28/00; B21D31/02; C21D9/46; C22C38/00; C22C38/04; B21D53/88
Domestic Patent References:
2002-09-03
2003-11-19
2000-02-02
2000-02-08
2002-04-09