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.

Date of Patent:
May. 01, 2012

Filed:

Jun. 15, 2011
Applicants:

Karin Shibata, Oyabe, JP;

Tomoo Yoshida, Namerikawa, JP;

Hiroshi Tabuchi, Tsukuba, JP;

Hidetoshi Takagi, Toyama, JP;

Inventors:

Karin Shibata, Oyabe, JP;

Tomoo Yoshida, Namerikawa, JP;

Hiroshi Tabuchi, Tsukuba, JP;

Hidetoshi Takagi, Toyama, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C22F 1/05 (2006.01);
U.S. Cl.
CPC ...
Abstract

A method includes: preparing a molten aluminum alloy consisting of 0.3-0.8 mass % Mg, 0.5-1.2 mass % Si, 0.3 mass % or more excess Si relative to the MgSi stoichiometric composition, 0.05-0.4 mass % Cu, 0.2-0.4 mass % Mn, 0.1-0.3 mass % Cr, 0.2 mass % or less Fe, 0.2 mass % or less Zr, and 0.005-0.1 mass % Ti, with the balance being aluminum and unavoidable impurities; casting the alloy into a billet at a speed of 80 mm/min or more and a cooling rate of 15° C./sec or more; extruding the billet into an extruded product; water cooling the product immediately after extrusion at 500° C./min or more; and artificially aging the product, thereby yielding an extruded product with fatigue strength of 140 MPa or more, fatigue ratio of 0.45 or more, an interval between striations on a fatigue fracture surface of 5.0 μm or less, and a maximum length of Al—Fe—Si crystallized products of 10 μm or less.


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