Jfe Steel Corporation

Ricoh Company, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Keiji Ueda

Shinichi Suzuki

Takeshi Yokota

Shinjiro Kaneko

Yoshiyasu Kawasaki

Kazuhiro Seto

Kazukuni Hase

Atsushi Takada

Reiko Sugihara

Shigeki Kitsuya

Shinichi Miura

Yoshie Obata

Naoki Takayama

Naoya Hayakawa

Masami Iwasaki

Koichi Nakashima

Satoshi Igi

Daichi Izumi

Tomohiro Ono

Yasuhiro Murota

Ryo Arao

Peng Han

Shohei Kozuki

The steel of the present disclosure contains, in mass %, C: 0.100% to 0.700%, Si: 0.05% to 1.00%, Mn: 20.0% to 40.0%, P: ≤0.030%, S: ≤0.0050%, Al: 0.01% to 5.00%, Cr: 0.5% to 7.0%, N: 0.0050% to 0.0500%, O: ≤0.0050%, Ti: ≤0.005%, Nb: ≤0.005%, and at least one selected from Ca: 0.0005% to 0.0100%, Mg: 0.0005% to 0.0100%, and REM: 0.0010% to 0.0200%, and has a microstructure with austenite as matrix, where an average grain size is 50 μm or less, a cleanliness of sulfide inclusion is less than 1.0%, a yield strength is 400 MPa or more, and a percent brittle fracture after a Charpy impact test at −269° C. is less than 5%.

Steel and method of producing same

Growing community of inventors

Tokyo, Japan

Keiji Ueda