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Title:
METHOD FOR MANUFACTURING HIGH TENSION STEEL WITH HIGH YIELD POINT
Document Type and Number:
Japanese Patent JP2002220622
Kind Code:
A
Abstract:

To provide a method for manufacturing high tension steel with a high yield point of 450 MPa or more, as well as a superior toughness and weldability, without adding a special process or a large quantity of alloy elements.

This method for manufacturing the steel comprises; heating steel which includes 0.03-0.15% C, 0.10-0.50% Si, 0.5-2.0% Mn, 0.05% or less P, 0.02% or less S, 0.001-0.10% Nb, 0.001-0.10% V, by mass%, and which satisfies PCM ≤0.25%; hot rolling it; and immediately cooling it down from a temperature range of Ar3 point or higher, to a temperature range of 350-650°C, at a cooling speed of 5°C/s or higher. PCM=C+Si/30+(Mn+Cu+Cr)/20+Mo/15+Ni/60+V /10+5B.


Inventors:
SADASUE TERUKI
SUZUKI SHINICHI
Application Number:
JP2001016558A
Publication Date:
August 09, 2002
Filing Date:
January 25, 2001
Export Citation:
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Assignee:
NIPPON KOKAN KK
International Classes:
C21D8/02; C22C38/00; C22C38/12; C22C38/58; (IPC1-7): C21D8/02
Domestic Patent References:
JPS62174324A1987-07-31
JPH05112823A1993-05-07
JP2000119746A2000-04-25
Attorney, Agent or Firm:
Yasumitsu Nakahama