US Patent No: 8,177,925

Number of patents in Portfolio can not be more than 2000

High-tensile steel plate, welded steel pipe or tube, and methods of manufacturing thereof

ALSO PUBLISHED AS: 20090297872

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Abstract

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In a high-tensile steel plate according to the invention, the carbon equivalent Pcm represented in Expression (1) is from 0.180% to 0.220%, the surface hardness is a Vicker's hardness of 285 or less, the ratio of a Martensite Austenite constituent in the surface layer is not more than 10%, the ratio of a mixed structure of ferrite and bainite inside beyond the surface layer is not less than 90%, the ratio of the bainite in the mixed structure is not less than 10%, the thickness of the lath of bainite is not more than 1 μm, the length of the lath is not more than 20 μm, and the segregation ratio as the ratio of the Mn concentration in the center segregation part relative to the Mn concentration at a part in a depth equal to ¼ of the thickness of the plate from the surface is not more than 1.3. Pcm=C+Si/30+(Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B . . . (1) where the element symbols in Expression (1) represent the % by mass of the respective elements. In this way, the high-tensile steel plate according to the invention has a yield strength of at least 551 MPa and a tensile strength of at least 620 MPa as well as high toughness, high propagating shear fracture and high weldability.

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Patent Owner(s)

Patent OwnerAddressTotal Patents
SUMITOMO METAL INDUSTRIES, LTD.OSAKA427

International Classification(s)

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Hamada, Masahiko Ikeda, JP 33 115
Okaguchi, Shuji Yao, JP 7 38
Seta, Ichirou - 2 1
Takahashi, Nobuaki Tokyo, JP 222 1660
Yamanaka, Akihiro Kanagawa, JP 113 1285

Cited Art Landscape

Patent Info (Count) # Cites Year
 
NIPPON STEEL CORPORATION (1)
2003/0217,795 High-strength steel sheet and high-strength steel pipe excellent in deformability and method for producing the same 9 2003
* Cited By Examiner

Patent Citation Ranking

Forward Cite Landscape

Patent Info (Count) # Cites Year
 
EXXONMOBIL RESEARCH AND ENGINEERING COMPANY (1)
* 2010/0136,369 High strength and toughness steel structures by friction stir welding 1 2009
 
VEYANCE TECHNOLOGIES, INC. (1)
6,402,128 Air spring with lateral restraint and axial control 12 2000
* Cited By Examiner

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