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:
Sep. 12, 2017
Filed:
Mar. 25, 2010
Shinya Sakamoto, Tokyo, JP;
Takuya Hara, Tokyo, JP;
Yoshio Terada, Tokyo, JP;
Takafumi Sebayashi, Tokyo, JP;
Itsuroh Hiroshige, Tokyo, JP;
Shinya Sakamoto, Tokyo, JP;
Takuya Hara, Tokyo, JP;
Yoshio Terada, Tokyo, JP;
Takafumi Sebayashi, Tokyo, JP;
Itsuroh Hiroshige, Tokyo, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
Abstract
Electric resistance welded steel pipe excellent in deformability and fatigue properties after quenching which enables working into complicated shapes without spheroidization and which improves the fatigue properties after cold working and quenching without carburization are provided. The electric resistance welded steel pipe is characterized by containing, by mass %, C: 0.15 to 0.55%, Si: 0.01 to 0.30%, Mn: 0.5 to 1.5%, Ca: 0.0010 to 0.0030%, S: 0.0005 to 0.0050%, and O: 0.0005 to 0.0050%, having contents of Ca, O, and S satisfying 0.10≦[Ca](1−124[O])/1.25[S]≦2.50, having Ca-based inclusions present at the base material and electric resistance weld zone with an average particle size of 1.0 to 10 μm and a density of 3 to 300/mm, and having a difference ΔHv of the maximum hardness of the electric resistance weld zone and the average hardness of the base material part satisfying 100 to 500.