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:
May. 17, 1988
Filed:
Aug. 05, 1987
James R Spencer, Sayre, PA (US);
De Wayne Grover, Towanda, PA (US);
GTE Products Corporation, Stamford, CT (US);
Abstract
A process is disclosed for producing tungsten heavy alloy billets. The process involves forming a uniform blend of elemental powders to form a tungsten alloy having a tungsten content of equal to or less than about 91% by weight and wherein the particle size of the tungsten is no less than about 2 micrometers in diameter. This blend is uniformly packed into a container having thermal expansion similar to that of the powder. The blend is then sintered in a hydrogen atmosphere at a temperature sufficient to impart strength to the powder and to reduce oxides and remove volatile impurities from the powder without significant densification in the powder. The powder is then solid state sintered in a reducing atmosphere at a sufficient temperature to densify the powder to at least about 90% of the theoretical density but at a temperature below the liquid phase sintering temperature of the powder, to form the billet. If the tungsten content of the alloy is greater than about 88% by weight, the solid state sintered powder can then be liquid state sintered by slowly raising the temperature from the solid state sintering temperature to the liquid phase sintering temperature and holding at this temperature for a sufficient time to accomplish the liquid sintering and achieve a density of greater than about 99% of the theoretical density in the billet.