Metal treatment – Process of modifying or maintaining internal physical... – Heating or cooling of solid metal
Reexamination Certificate
2011-03-22
2011-03-22
Yee, Deborah (Department: 1733)
Metal treatment
Process of modifying or maintaining internal physical...
Heating or cooling of solid metal
C148S659000, C148S662000, C148S654000
Reexamination Certificate
active
07909950
ABSTRACT:
The present invention provides an ultra soft high carbon hot-rolled steel sheet. The ultra soft high carbon hot-rolled steel sheet contains 0.2% to 0.7% of C, 0.01% to 1.0% of Si, 0.1% to 1.0% of Mn, 0.03% or less of P, 0.035% or less of S, 0.08% or less of Al, 0.01% or less of N, and the balance being Fe and incidental impurities and further contains 0.0010% to 0.0050% of B and 0.05% to 0.30% of Cr in some cases. In the texture of the steel sheet, an average ferrite grain diameter is 20 μm or more, a volume ratio of ferrite grains having a grain diameter of 10 μm or more is 80% or more, and an average carbide grain diameter is in the range of 0.10 to less than 2.0 μm. In addition, the steel sheet is manufactured by the steps, after rough rolling, performing finish rolling at a reduction ratio of 10% or more and at a finish temperature of (Ar3−20° C.) or more in a final pass, then performing first cooling within 2 seconds after the finish rolling to a cooling stop temperature of 600° C. or less at a cooling rate of more than 120° C./sec, then performing second cooling so that the steel thus processed is held at 600° C. or less, then performing coiling at 580° C. or less, followed by pickling, and then performing spheroidizing annealing at a temperature in the range of 680° C. to the Ac1transformation point.
REFERENCES:
patent: 2005/0199322 (2005-09-01), Nakamura et al.
patent: 2 000 552 (2008-12-01), None
patent: 2 000 552 (2008-12-01), None
patent: 64-025946 (1989-01-01), None
patent: 08-246051 (1996-09-01), None
patent: 09-157758 (1997-06-01), None
patent: 11-080884 (1999-03-01), None
patent: 11-256268 (1999-09-01), None
patent: 2001-220642 (2001-08-01), None
patent: 2003-073742 (2003-03-01), None
Machine-English translation of Japnaese patent 2003-013145, Fujita Takeshi et al., Jan. 15, 2003.
English abstract of Japanese patent 2005-131660, Makoto Suzuki et al., May 26, 2005.
Aoki Naoya
Fujita Takeshi
Kimura Hideyuki
Mitsuzuka Ken-ichi
Nakamura Nobuyuki
Holtz, Holtz, Goodman & Chick, P.C.
JFE Steel Corporation
Yee Deborah
LandOfFree
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