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.

Date of Patent:
Jun. 04, 2002

Filed:

Dec. 29, 2000
Applicant:
Inventor:

John M. Warren, North Reading, MA (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J 3/510 ;
U.S. Cl.
CPC ...
H01J 3/510 ;
Abstract

A joining method designed to minimize the temperature needed to obtain a high strength braze joint between a molybdenum alloy substrate and a graphite disk used in a rotating anode X-ray tube target used for computed tomography applications. The method consists of two separate brazing operations. The first brazing operation joins a thin molybdenum sheet to the graphite disk using a pure metal braze to form a plated graphite subassembly. The second brazing operation joins the plated graphite subassembly to the molybdenum alloy substrate using a highly specialized braze alloy having a melt temperature below the recrystallization temperature of said molybdenum alloy substrate and a remelt temperature after brazing above the recrystallization temperature of said molybdenum alloy substrate. This two step brazing reduces the probability of fracture in the graphite by maintaining the elevated temperature yield strength normally developed in forged molybdenum alloy substrates by avoiding the deleterious yield strength reduction associated with recrystallization of the molybdenum alloy substrate.


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