The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 19, 2015
Filed:
Apr. 17, 2012
Satoru Ohsaki, Hokkaido, JP;
Kazuhiro Miki, Hokkaido, JP;
Tsukasa Azuma, Hokkaido, JP;
Koji Kajikawa, Hokkaido, JP;
Shigeru Suzuki, Hokkaido, JP;
Masayuki Yamada, Yokohama, JP;
Itaru Murakami, Tokyo, JP;
Kenichi Okuno, Yokohama, JP;
Liang Yan, Yokohama, JP;
Reki Takaku, Yokohama, JP;
Akihiro Taniguchi, Yokohama, JP;
Tetsuya Yamanaka, Yokohama, JP;
Makoto Takahashi, Yokohama, JP;
Kenichi Imai, Yokohama, JP;
Osamu Watanabe, Yokohama, JP;
Joji Kaneko, Tokyo, JP;
Satoru Ohsaki, Hokkaido, JP;
Kazuhiro Miki, Hokkaido, JP;
Tsukasa Azuma, Hokkaido, JP;
Koji Kajikawa, Hokkaido, JP;
Shigeru Suzuki, Hokkaido, JP;
Masayuki Yamada, Yokohama, JP;
Itaru Murakami, Tokyo, JP;
Kenichi Okuno, Yokohama, JP;
Liang Yan, Yokohama, JP;
Reki Takaku, Yokohama, JP;
Akihiro Taniguchi, Yokohama, JP;
Tetsuya Yamanaka, Yokohama, JP;
Makoto Takahashi, Yokohama, JP;
Kenichi Imai, Yokohama, JP;
Osamu Watanabe, Yokohama, JP;
Joji Kaneko, Tokyo, JP;
THE JAPAN STEEL WORKS,LTD., Tokyo, JP;
KABUSHIKI KAISHA TOSHIBA, Tokyo, JP;
Abstract
A low alloy steel ingot contains from 0.15 to 0.30% of C, from 0.03 to 0.2% of Si, from 0.5 to 2.0% of Mn, from 0.1 to 1.3% of Ni, from 1.5 to 3.5% of Cr, from 0.1 to 1.0% of Mo, and more than 0.15 to 0.35% of V, and optionally Ni, with a balance being Fe and unavoidable impurities. Performing quality heat treatment including a quenching step and a tempering step to the low alloy steel ingot to obtain a material, which has a grain size number of from 3 to 7 and is free from pro-eutectoid ferrite in a metallographic structure thereof, and which has a tensile strength of from 760 to 860 MPa and a fracture appearance transition temperature of not higher than 40° C.