Wire-Like Product with Composite Core and Process for Producing the Same

Abstract

A wire-like product ( 10 ) for use as a feedstock in metal or plasma spraying or welding includes a metal case ( 12 ) and a composite core ( 14 ) in the case, with the core being partially sintered and containing enough metal to conduct an electrical current. To form the wire-like product, a metal tubular segment ( 20 ) is filled with a powder ( 26 ) in the absence of oxygen. Then the tubular segment is reduced in cross-section to compact the powder within it. Next the tubular segment is heated to anneal it and effect a partial sinter ( 32 ) of the powder. Another reduction in cross section breaks the partial sinter into particles and further compacts them, whereas a further heating anneals the tubular segment and resinters the particles. Repetitions of the cycle produce the wire-like product.

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       14 . A process for producing a consumable wire for use for metal or plasma spraying or for welding, said process comprising:
 providing a metal tubular segment;   introducing an inert gas into the tubular segment;   while the interior of the tubular segment contains the inert gas, filling the metal tubular segment with a powder containing at least 5% metal by volume;   reducing the cross-sectional size of the metal tubular segment containing the powder to compact the powder within it;   thereafter repeatedly heating the metal tubular segment and reducing the cross-sectional size of the tubular segment, with the heating raising the temperature of the tubular segment to less than the melting temperature for the metal of the tubular segment, yet high enough anneal the tubular segment, and effecting an annealing of the tubular segment and a partial sinter of powder, the repeated reduction in the cross-sectional size of the tubular segment fracturing the partial sinter into particles that are again partially sintered in the subsequent heating; and   whereby a wire is produced with a metal case and a partially sintered core having at least 5% metal by volume, but having no grain structure.   
   
   
       15 . The process according to  claim 1  wherein the heating of the tubular segment occurs in the absence of oxygen. 
   
   
       16 . The process according to  claim 1  wherein the tubular segment is formed from a metal selected from a group consisting of nickel and its alloys, stainless steel, cobalt alloys, and alloys of refractory metals. 
   
   
       17 . The process according to  claim 1  wherein the powder in addition to the metal includes carbides or metalloids or ceramics or a mixture of some of all of the foregoing. 
   
   
       18 . The process according to  claim 1  and further comprising joining multiple tubular segments together end to end. 
   
   
       19 . The process according to  claim 6  wherein the multiple tubular segments are joined end to end by welding in an oxygen-free atmosphere. 
   
   
       20 . The process of  claim 1  wherein the inert gas that is introduced into the tubular segment is argon. 
   
   
       21 . The process according to  claim 1  wherein the inert gas is heavier than air and is introduced into the tubular segment at the top of the tubular segment with the tubular segment being in a generally upright orientation. 
   
   
       22 . The process according to  claim 8  wherein the powder is introduced into the tubular segment at the top of the tubular segment and displaces the inert gas. 
   
   
       23 . A consumable wire formed by the process of  claim 1 .