Jfe Steel Corporation

Yutaka Awajiya

Keiji Watanabe

Hiroshi Matsuda

Makoto Suzuki

Tatsuya Nakagaito

Naoki Kikuchi

Nobuyuki Ishikawa

Yasunobu Nagataki

Yukinori Iizuka

Norichika Aramaki

Takayuki Futatsuka

Masayuki Nakada

Koichi Tsutsumi

Nobuo Shikanai

Mikio Suzuki

Keigo Toishi

Shinichi Kakihara

Tomohiro Matsushima

Makoto Iiyama

Akiyoshi Tsuji

In the continuous steel casting method of the present invention, a gap between strand support rolls with a strand in a rectangular shape interposed therebetween is increased toward a downstream side in a casting direction to thereby bulge the strand having an unsolidified layer thereinside such that the thickness between long-side surfaces of the strand increases within the range of 0.1% or more and 10% or less of the thickness of the strand inside a mold. A portion of the strand in which the solid phase fraction in a central portion of the strand is within the range of 0.2 or more and less than 0.9 satisfies a prescribed total rolling reduction and a prescribed reduction gradient, and a portion of the strand in which the solid phase fraction is within the range of 0.9 or more satisfies a prescribed total rolling reduction and a prescribed reduction gradient.

Continuous steel casting method

A steel plate for line pipes containing, in terms of % by weight, C: 0.02 to 0.06%, Si: 0.5% or less, Mn: 0.8 to 1.6%, P: 0.008% or less, S: 0.0008% or less, Al: 0.08% or less, Nb: 0.005 to 0.035%, Ti: 0.005 to 0.025%, and Ca: 0.0005 to 0.0035%, and optionally contains one or more of Cu: 0.5% or less, Ni: 1% or less, Cr: 0.5% or less, Mo: 0.5% or less and V: 0.1% or less, and has a CP value of 0.95 or less represented by CP=4.46C(%)+2.37Mn(%)/6+{1.18Cr(%)+1.95Mo(%)+1.74V(%)}/5+{1.74Cu(%)+1.7Ni(%)}/15+22.36P(%), and a Ceq value of 0.30 or more represented by Ceq=C(%)+Mn(%)/6+{Cr(%)+Mo(%)+V(%)}/5 +{Cu(%)+Ni(%)}/15.

Steel plate and steel pipe for line pipes

An immersion nozzle for continuous casting of steel supplies molten steel into a mold. At least a part of the immersion nozzle is formed of a refractory having a desulfurizing ability. A method for continuous casting of steel employs the immersion nozzle to supply molten steel into a mold using the immersion nozzle for continuous casting.

Immersion nozzle for continuous casting of steel and method of continuous casting method of steel

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Tokyo, Japan

Yutaka Awajiya