Method for strengthening pressure resistance of a hollowed metallic structure and a pressure resistant structure made thereby

摘要

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.