Jfe Steel Corporation

Kabushiki Kaisha Kobe Seiko Sho

Kaoru Nagatani

Mitsuhiro Okatsu

Fumimaru Kawabata

Naoya Hayakawa

Shigeki Nishiyama

Keito Ishizaki

Makoto Ota

Shuichi Sakaguchi

A high-strength steel pipe has a tensile strength of 800 MPa or more and includes a weld metal having high cold-cracking resistance and high low-temperature toughness, wherein the weld metal contains C: 0.04% to 0.09% by mass, Si: 0.32% to 0.50% by mass, Mn: 1.4% to 2.0% by mass, Cu: less than 0.5% by mass, Ni: more than 0.9% by mass but not more than 4.2% by mass, Mo: 0.4% to 1.5% by mass, Cr: less than 0.5% by mass, V: less than 0.2% by mass, and the remainder of Fe and incidental impurities, and CS values calculated from the weld metal components using the equation CS=5.1+1.4[Mo]&#x2212;[Ni]&#x2212;[Mn]&#x2212;36.3[C] are equal to zero or more at both an internal surface and an external surface.

High-strength welded steel pipe including weld metal having high cold-cracking resistance and method for manufacturing the same

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Kanagawa, Japan

Kaoru Nagatani