# US 2013/0156493 A1 · Method of joining titanium and titanium-based alloys to ferrous metals using tantalum

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- Number: US 2013/0156493 A1
- Document ID: US20130156493A1
- Status: Published application
- Kind: A1
- Application number: 13/327,055
- Filed: 2011-12-15
- Published: 2013-06-20
- Earliest claimed: 2011-12-15
- Assignees: Lake Region Manufacturing, Inc.
- Inventors: Anthony Hausladen; Mark Steven Lewandowski; Ryan Bennett Sefkow
- Web page: https://patentgrep.com/patent/US20130156493A1

## CPC

- B23K 9/232: {of different metals}
- B23K 15/0093: {characterised by the properties of the materials to be welded}
- B23K 26/26: of rectilinear seams
- B23K 26/32: taking account of the properties of the material involved
- B23K 26/323: involving parts made of dissimilar metallic material
- B23K 2101/18: Sheet panels
- B23K 2103/08: Non-ferrous metals or alloys
- B23K 2103/24: Ferrous alloys and titanium or alloys thereof
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM

## Abstract

A method of joining, e.g., by fusion welding, titanium, and titanium-based alloys to ferrous metals, and the intermetallic weld pool created by practice of the method is described. The instant invention involves the use, inclusion or deployment of tantalum into the weld pool and upon cooling a weld, to create a surprisingly strong intermetallic bond, weld, or joint.

## Claims

### Claim 1

A method of joining titanium, or a titanium-based alloy, to a ferrous metal to produce a strong ductile weld, comprising the steps of:
placing at least one titanium or a titanium-based alloy workpiece in close proximity to a ferrous metal workpiece thereby defining a joint precursor;
adding a quantity of tantalum substantially at the joint precursor; and
fusion welding the joint precursor thereby producing a weld pool incorporating a portion of the at least one titanium, or titanium-based alloy workpiece, a portion of the ferrous metal workpiece, and a portion of the tantalum
permitting the weld pool to cool and form a weld.

### Claim 2 (depends on 1)

The method of claim 1, wherein the at least one titanium, or titanium-based alloy workpiece is nickel-titanium and the at least one ferrous metal workpiece is stainless steel.

### Claim 3 (depends on 1)

The method of claim 1, further including a step of cleaning the titanium, or the titanium-based alloy workpiece and the ferrous metal workpiece to remove contaminants.

### Claim 4 (depends on 1)

The method of claim 1, wherein the titanium, or the titanium-based alloy workpiece is a titanium, or titanium-based alloy wire, and the ferrous metal workpiece is a ferrous metal wire.

### Claim 5 (depends on 1)

The method of claim 1, wherein the titanium, or the titanium-based alloy wire is nickel-titanium, the ferrous metal wire is stainless steel.

### Claim 6 (depends on 1)

The method of claim 1 wherein fusion welding means producing the weld pool by the use of a beam of a laser.

### Claim 7 (depends on 6)

The method of claim 6, wherein the laser beam is pulsed during the fusion welding.

### Claim 8 (depends on 1)

A method according to claim 1 wherein the titanium or titanium-based alloy is nitinol.

### Claim 9 (depends on 1)

A method according to claim 1 wherein the ferrous metal is stainless steel.

### Claim 10 (depends on 1)

A method according to claim 1 wherein the titanium or titanium-based alloy workpiece and the ferrous metal workpiece are components of a medical device.

### Claim 11 (depends on 10)

A method according to claim 10 wherein the titanium or titanium-based alloy workpiece is a core wire for a guidewire and the ferrous metal workpiece is a stainless steel guidewire coil.

### Claim 12

A method of joining a titanium-based alloy to a ferrous metal to produce a strong ductile weld, comprising the steps of:
placing at least one nickel-titanium workpiece in close proximity to a stainless steel workpiece thereby defining a joint precursor;
placing a tantalum workpiece at the joint precursor; and
fusion welding the joint precursor thereby producing a weld pool incorporating the tantalum;
permitting the weld pool to cool and to solidify producing a weld having enhanced joint or weld.

### Claim 13 (depends on 12)

A method according to claim 12 wherein the nickel titanium workpiece is a nitinol core wire of a medical guidewire and stainless steel workpiece is a stainless steel coil for a guidewire.

### Claim 14 (depends on 12)

A method according to claim 12 wherein the titanium or titanium-based alloy is nitinol.

### Claim 15

A weld pool consisting essentially of a fusion of nickel-titanium alloy, ferrous alloy and tantalum.

### Claim 16 (depends on 15)

A weld pool according to claim 15 wherein the nickel titanium alloy is nitinol, and the ferrous metal alloy is stainless steel.

### Claim 17 (depends on 12)

A method according to claim 12 wherein the weld-pool is substantially free of brittle intermetallic compounds.