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. 20, 1988
Filed:
Feb. 17, 1987
Applicant:
Inventors:
Kunio Enomoto, Ibaraki, JP;
Tasuku Shimizu, Hitachi, JP;
Shinji Sakata, Katsuta, JP;
Terunobu Koike, Nakaminato, JP;
Nobuo Shimizu, Hitachi, JP;
Tsukasa Ikegami, Hitachi, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D / ;
U.S. Cl.
CPC ...
148 / ; 148127 ; 148154 ;
Abstract
A method for improving residual stress in a circumferential weld zone of a piping and the like which includes preventing deformation of the weld zone, and causing a local expansion or contraction of a portion of the piping axially spaced from the weld zone thereby effecting a plastic working so as to increase or decrease the diameter of piping. The method can effectively be applied to apparatus and pipe system which are used in a corrosive environment and under action of a static or dynamic outer load.