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. 06, 1998
Filed:
Sep. 30, 1997
Edwin S Hodge, Ocala, FL (US);
Robert F Tavenner, Crossville, TN (US);
Ametek Specialty Metal Products Division, Wallingford, CT (US);
Abstract
A pneumatic isostatic forging process for densification of near net shape workpieces is disclosed. In the process, a workpiece is heated prior to the forging process, such as from a previous processing step. The workpiece is loaded into a pressure vessel. The pressure in the vessel is ramped to an operating pressure and held for approximately 10-120 seconds. The vessel is pressurized using rapid pressurization to achieve a high strain rate to assist in the final closure of voids within the workpiece, with the increase in the strain rate lowering the flow stress requirements for the workpiece, thereby making the workpiece more susceptible to plastic deformation. The rapid pressurization serves to densify the gas within the vessel, thereby increasing the viscosity of the gas in order to substantially reduce or altogether prevent absorption of the gas into the workpiece in order to sustain a differential between the internal pressure and the surface pressure of the workpiece, thereby allowing plastic deformation to take place through a collapsing of the material, or removal of the voids. After pressurization of the vessel for a prescribed period of time, it is depressurized and the workpiece is unloaded.