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:
Oct. 11, 2016
Filed:
Oct. 31, 2011
Yoshihiko Nozaki, Higashimatsuyama, JP;
Makoto Taguchi, Sakado, JP;
Kazuhiro Hirakawa, Ageo, JP;
UD TRUCKS CORPORATION, Ageo-shi, JP;
Abstract
The purpose of the present invention is to provide a method for improving fatigue strength that is capable of improving the fatigue strength of cast iron, specifically spherical graphite cast iron, to the same level as that of carbon steel subjected 10 carburizing and quenching. To this end, this method contains a step for performing first, second and third shot peenings using shot of a prescribed diameter for each on spherical graphite cast iron on which a quenching and tempering heat treatment or austempering heat treatment has been performed and tensile strength made to be 1200 MPa or more, the spherical graphite cast iron containing the following elements in the following mass percentages: C=2.0-4.0%, Si=1.5-4.5%, Mn=2.0% or less, P=O.08% or less, 8=0.03% or less, Mg=0.02-0.1%, and Cu=1.8-4.0%.