Nippon Steel Sumitomo Metal Corporation

Takehiro Inoue

Tadashi Ishikawa

Yasunori Takahashi

Ryuji Uemori

Naoki Saitoh

Hitoshi Furuya

Motohiro Okushima

Akira Itoh

Jun Otani

A Ni-added steel plate contains, by mass %, C: 0.03% to 0.10%, Si: 0.02% to 0.40%, Mn: 0.3% to 1.2%, Ni: 5.0% to 7.5%, Cr: 0.4% to 1.5%, Mo: 0.02% to 0.4%, Al: 0.01% to 0.08%, T.O: 0.0001% to 0.0050%, P: limited to 0.0100% or less, S: limited to 0.0035% or less, and N: limited to 0.0070% or less with a remainder composed of Fe and inevitable impurities, in which a Ni segregation ratio at a position of &#xbc; of a plate thickness away from a plate surface in a thickness direction is 1.3 or less, a fraction of austenite after deep cooling is 2% or more, an austenite unevenness index after deep cooling is 5.0 or less, and an average equivalent circle diameter of austenite after deep cooling is 1 &#x3bc;m or less.

Ni-added steel plate and method of manufacturing the same

Growing community of inventors

Tokyo, Japan

Takehiro Inoue