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:
Feb. 23, 2010
Filed:
Nov. 26, 2004
Hiroshi Yaguchi, Kobe, JP;
Koichi Sakamoto, Kobe, JP;
Tomoko Sugimura, Kobe, JP;
Goro Anan, Kobe, JP;
Katsuhiko Ozaki, Kobe, JP;
Hiroshi Yaguchi, Kobe, JP;
Koichi Sakamoto, Kobe, JP;
Tomoko Sugimura, Kobe, JP;
Goro Anan, Kobe, JP;
Katsuhiko Ozaki, Kobe, JP;
Kabushiki Kaisha Kobe Seiko Sho, Kobe-shi, JP;
Abstract
The present invention provides a low-carbon resulfurized free machining steel product excellent in machinability typified by finished surface roughness even though toxic Pb or special elements such as Bi or Te are not added, and a suitable production method thereof. A steel product has a specific composition, has contents of Mn and S satisfying the following conditions: 0.40≦Mn*S≦1.2 and Mn/S≧3.0, and contains a ferrite-pearlite structure as the metallographic structure, in which the average width (μm) of sulfide inclusions in the steel product is 2.8*(log d) or more, wherein d (mm) is the diameter of the steel product, and pro-eutectoid ferrite in the metallographic structure has a hardness HV of 133 to 150 or a difference in deformation resistance at a strain of 0.3 between 200° C. and 25° C. is 110 MPa or more and 200 MPa or less, the deformation resistances being determined in a compression test at a deformation rate of 0.3 mm/min.