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:
Jul. 28, 2009
Filed:
May. 30, 2006
Satoru Aoike, Tokai, JP;
Masakazu Hisatsune, Hitachi, JP;
Satoru Aoike, Tokai, JP;
Masakazu Hisatsune, Hitachi, JP;
Hitachi-GE Nuclear Energy, Ltd., Ibaraki, JP;
Abstract
An method for converting tensile residual stress on an inner surface of a welded part of a pipe to compressive residual stress with use of ice plugs formed by cooling the pipe from the outer surface, comprises the steps of: placing refrigerant containers for forming the ice plugs in the upstream and downstream of a butt-welded part; cooling the outer surface of the pipe to form the ice plugs; and then cooling the outer surface of the pipe with use of at least one refrigerant container for expanding the pipe arranged between the refrigerant containers for forming the ice plugs. When the method is applied to a pipe with a large inside diameter, the method comprises forming the ice plugs at a curved pipe, an elbow or a branch pipe in the upstream and downstream of the butt-welded part.