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.
AKAMATSU SATOSHI
HAYASHI KUNIO
SENUMA TAKEHIDE
JP2002248525A | 2002-09-03 | |||
JP2003328031A | 2003-11-19 | |||
JP2000033435A | 2000-02-02 | |||
JP2000038640A | 2000-02-08 | |||
JP2002102980A | 2002-04-09 |
Etsuichi Matsumoto
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