Composite medical device having a titanium or titanium based alloy section and a ferrous metal section

Abstract

A composite medical device having a titanium, and titanium based alloy, section welded to a ferrous metal section. The weld provides supplementary filler material to alter the proportions of various elements in the weld pool to ensure a strong and reliable weld. Certain fillers, such as nickel or iron, added to the weld pool enable high quality welds to be fabricated utilizing a wide variety of fusion welding techniques between the titanium, or titanium based alloy, section and the ferrous metal section. The sections may include nickel-titanium, also known as nitinol. The sections may be in the form of wires, bars, ribbons, and sheets. The composite medical device of the present invention may include guidewires, stents, right-angle needles, suture passers, retractors, graspers, baskets, and various retrieval devices.

1 . A composite medical device, comprising: 
 (a) a titanium, or a titanium based alloy, section;    (b) a ferrous metal section, joined to the titanium, or a titanium based alloy, section by a weld;    (c) the weld produced by creating a shielded weld pool incorporating (1) a portion of the titanium, or titanium based alloy, section, (2) a portion of the ferrous metal section, and (3) a portion of a filler material, to achieve a predetermined composition of the weld pool.    
     
     
         2 . The device of  claim 1 , wherein the filler material contains nickel.  
     
     
         3 . The device of  claim 1 , wherein the filler material contains iron.  
     
     
         4 . The device of  claim 1 , wherein the titanium, or titanium based alloy, section is nickel-titanium and the ferrous metal section is stainless steel.  
     
     
         5 . The device of  claim 1 , wherein the titanium, or titanium based alloy, section is stress relieved prior to welding.  
     
     
         6 . The device of  claim 1 , wherein the titanium, or the titanium based alloy, section is a titanium, or titanium based alloy, wire having a first diameter, and the ferrous metal section is a ferrous metal wire having a second diameter.  
     
     
         7 . The device of  claim 6 , wherein the titanium, or the titanium, or the titanium based alloy, wire is a stranded wire.  
     
     
         8 . The device of  claim 6 , wherein the titanium, or the titanium, or the titanium based alloy, wire is a braided wire.  
     
     
         9 . The device of  claim 6 , wherein the composite medical device is a guidewire.  
     
     
         10 . The device of  claim 6 , wherein the titanium, or the titanium based alloy, wire is nickel-titanium, the ferrous metal wire is stainless steel, and the filler material is substantially pure nickel.  
     
     
         11 . The device of  claim 6 , wherein the titanium, or the titanium based alloy, wire is nickel-titanium, the ferrous metal wire is stainless steel, and the filler material is substantially pure iron.  
     
     
         12 . The device of  claim 10 , wherein the predetermined composition of the weld pool is approximately equal parts by weight of nickel-titanium, stainless steel, and nickel.  
     
     
         13 . The device of  claim 11 , wherein the predetermined composition of the weld pool is approximately equal parts by weight of nickel-titanium, stainless steel, and iron.  
     
     
         14 . The device of  claim 1 , wherein the titanium, or the titanium based alloy section, is a titanium, or titanium based alloy, tube having a first diameter, and the ferrous metal section is a ferrous metal tube having a second diameter.  
     
     
         15 . The device of  claim 14 , wherein the composite medical device is a stent.  
     
     
         16 . The device of  claim 14 , wherein the titanium, or the titanium based alloy, tube is nickel-titanium, the ferrous metal tube is stainless steel, and the filler material is substantially pure nickel.  
     
     
         17 . The device of  claim 14 , wherein the titanium, or the titanium based alloy, tube is nickel-titanium, the ferrous metal tube is stainless steel, and the filler material is substantially pure iron.  
     
     
         18 . The device of  claim 16 , wherein the predetermined composition of the weld pool is approximately equal parts by weight of nickel-titanium, stainless steel, and nickel.  
     
     
         19 . The device of  claim 17 , wherein the predetermined composition of the weld pool is approximately equal parts by weight of nickel-titanium, stainless steel, and iron.  
     
     
         20 . The device of  claim 1 , wherein the titanium, or the titanium based alloy, section is a titanium, or titanium based alloy, ribbon.  
     
     
         21 . The device of  claim 20 , wherein the titanium, or the titanium based alloy, ribbon is nickel-titanium, the ferrous metal section is stainless steel, and the filler material is substantially pure nickel.  
     
     
         22 . The device of  claim 20 , wherein the titanium, or the titanium based alloy, ribbon is nickel-titanium, the ferrous metal section is stainless steel, and the filler material is substantially pure iron.  
     
     
         23 . The device of  claim 21 , wherein the predetermined composition of the weld pool is approximately equal parts by weight of nickel-titanium, stainless steel, and nickel.  
     
     
         24 . The device of  claim 22 , wherein the predetermined composition of the weld pool is approximately equal parts by weight of nickel-titanium, stainless steel, and iron.  
     
     
         25 . The device of  claim 1 , wherein the titanium, or the titanium based alloy, section is a titanium, or titanium based alloy, sheet.  
     
     
         26 . The device of  claim 25 , wherein the titanium, or the titanium based alloy, sheet is nickel-titanium, the ferrous metal section is stainless steel, and the filler material is substantially pure nickel.  
     
     
         27 . The device of  claim 25 , wherein the titanium, or the titanium based alloy, sheet is nickel-titanium, the ferrous metal section is stainless steel, and the filler material is substantially pure iron.  
     
     
         28 . The device of  claim 26 , wherein the predetermined composition of the weld pool is approximately equal parts by weight of nickel-titanium, stainless steel, and nickel.  
     
     
         29 . The device of  claim 27 , wherein the predetermined composition of the weld pool is approximately equal parts by weight of nickel-titanium, stainless steel, and iron.  
     
     
         30 . The device of  claim 1 , wherein the weld has an ultimate strength of at least 84 ksi.  
     
     
         31 . A composite medical device, comprising: 
 (a) a nickel-titanium section;    (b) a stainless steel section, joined to the nickel-titanium section by a weld;    (c) the weld produced by creating a shielded weld pool incorporating (1) a portion of the nickel-titanium section, (2) a portion of the stainless steel section, and (3) a portion of a nickel containing filler material, to achieve a predetermined composition of the weld pool.    
     
     
         32 . The device of  claim 31 , wherein the filler material is substantially pure nickel.  
     
     
         33 . The device of  claim 31 , wherein the predetermined composition of the weld pool is approximately equal parts by weight of nickel-titanium, stainless steel, and nickel.  
     
     
         34 . A composite medical guidewire device, comprising: 
 (a) a nickel-titanium wire having a first diameter;    (b) a stainless steel wire having a second diameter, joined to the nickel-titanium wire by a weld;    (c) the weld having an ultimate strength of at least 84 ksi and being produced by creating a shielded weld pool incorporating (1) a portion of the nickel-titanium wire, (2) a portion of the stainless steel wire, and (3) a portion of a filler material containing nickel, to achieve a predetermined composition of the weld pool having approximately equal parts by weight of nickel-titanium, stainless steel, and nickel.