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:
Jun. 01, 1993
Filed:
Jan. 24, 1991
Takashi Matsunobu, Hitachi, JP;
Kenzi Aizawa, Hitachi, JP;
Kazumi Anazawa, Hitachi, JP;
Kunio Enomoto, Tokai, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A method for strengthening a pressure resistant property of a hollowed structure made of a metallic material and a pressure resistant hollowed structure made by such method. The method includes providing a temperature differential in a thickness direction between an outer side and an inner side of the metallic material with an arranged sufficient to generate a stress not exceeding a yielding stress of the metallic material. The outer side and inner side are pressurized so as to superimposed a stress generated by the pressurizing and the stress caused by the temperature differential reaching the yielding stress of the metallic material. The pressure is released subsequent to the superimposed stress reaching a level of the yielding stress of the metallic material. The compressive residual stress has a larger absolute value than a tensile stress caused in the inner side of the hollowed structure by the internal pressure, with the tensile residual stress in an outer side of the hollowed structure having a value of less than the tensile yielding stress of the metallic material even though the tensile stress is superimposed in the outer side of the hollowed structure by the internal pressure.