# US 6,294,738 B1 · Silver and silver alloy articles

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- Number: US 6,294,738 B1
- Document ID: US6294738B1
- Status: Granted
- Kind: B1
- Application number: 08/831,504
- Filed: 1997-03-31
- Granted: 2001-09-25
- Earliest claimed: 1997-03-31
- Assignees: American Superconductor Corporation
- Inventors: Jeffrey M. Seuntjens
- Web page: https://patentgrep.com/patent/US6294738B1

## CPC

- H10N 60/0801: {Manufacture or treatment of filaments or composite wires}
- B21C 23/085: {Making tubes (B21C23/10 take precedence)}
- Y10T 29/49014: Superconductor
- Y10T 29/49801: Shaping fiber or fibered material
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- B21C: MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method for fabricating silver or silver alloy tube stock. The method provides silver or silver alloy tube stock with a structure that is substantially free of defects, has a fine grain size, and is amenable to uniform deformation. The silver or silver alloy tube stock is used to make silver-superconductor monofilament or multifilament precursor articles and composites.

## Claims

### Claim 1

A superconducting article precursor comprising a superconductor or superconductor precursor contained in a thick-walled, seamless metal tube comprising silver or a silver alloy.

### Claim 2 (depends on 1)

The superconducting article precursor of claim 1, wherein the thick-walled, seamless metal tube has an outer diameter greater than 25 millimeters.

### Claim 3 (depends on 1)

The superconducting article precursor of claim 1, wherein the seamless metal tube is substantially free of major defects.

### Claim 4

A superconducting article precursor comprising a superconductor or superconducting precursor contained in a thick-walled, metal tube comprising silver or a silver alloy, wherein the metal tube has an average grain size less than 100 micrometers.

### Claim 5 (depends on 4)

The superconducting article precursor of claim 4, wherein the metal tube is free of casting porosity.

### Claim 6 (depends on 4)

The superconducting article precursor of claim 4, wherein the metal tube has an outer diameter greater than 2.5 millimeters.

### Claim 7 (depends on 6)

The superconducting article precursor of claim 6, wherein the metal tube is seamless.

### Claim 8 (depends on 4)

The superconducting article precursor of claim 4, wherein the average grain size is less than 20 micrometers.

### Claim 9 (depends on 8)

The superconducting article precursor of claim 8, wherein the metal tube has a maximum grain size less than about 100 micrometers.

### Claim 10 (depends on 9)

The superconducting article precursor of claim 9, wherein the maximum grain size is less than about 50 micrometers.

### Claim 11

A superconducting article precursor comprising a superconductor or superconductor precursor contained in a thick-walled, metal tube comprising silver or a silver alloy, wherein the metal tube is free of casting porosity.

### Claim 12 (depends on 11)

The superconducting article precursor of claim 11, wherein the metal tube has an outer diameter greater than 25 millimeters.

### Claim 13 (depends on 11)

The superconducting article precursor of claim 11, wherein the metal tube is seamless.

### Claim 14

A superconducting article precursor comprising a superconductor or superconductor precursor contained in a thick-walled, metal tube comprising silver or a silver alloy, wherein the metal tube is formed by extrusion.

### Claim 15 (depends on 14)

The superconducting article precursor of claim 14, wherein the metal tube has an outer diameter greater than 25 millimeters.

### Claim 16 (depends on 15)

The superconducting article precursor of claim 15, wherein the metal tube is formed by extruding a cast silver or silver alloy ingot having a bore therethrough.

### Claim 17 (depends on 16)

The superconducting article precursor of claim 16, wherein the metal tube is seamless, substantially free of casting porosity, surface folds, and surface cracks, and has an average grain size of less than 100 micrometers.