# US 8,784,997 B2 · Metallurgically bonded stainless steel

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- Number: US 8,784,997 B2
- Document ID: US8784997B2
- Status: Granted
- Kind: B2
- Application number: 14/052,709
- Filed: 2013-10-12
- Published: 2014-02-06
- Granted: 2014-07-22
- Earliest claimed: 2011-12-29
- Assignees: Arcanum Alloy Design Inc.
- Applicants: Arcanum Alloy Design Inc.
- Inventors: Daniel E. Bullard; Joseph E. McDermott
- Web page: https://patentgrep.com/patent/US8784997B2

## CPC

- B32B 15/011: {all layers being formed of iron alloys or steels}
- B23K 35/004: {at least one of the workpieces being of a metal of the iron group}
- B23K 35/0266: {flux-cored}
- B23K 35/308: {with Cr as next major constituent}
- B23K 35/3086: {containing Ni or Mn}
- B23K 35/365: Selection of non-metallic compositions of coating materials either alone or conjoint with selection of soldering or welding materials
- B23K 35/404: {Coated rods; Coated electrodes}
- B32B 1/08: Tubular products
- B32B 15/01: all layers being exclusively metallic {(making layered metal workpieces by pressure cladding B23K20/22; making coatings with a metallic material characterised by its composition C23C30/00)}
- C22C 38/18: containing chromium
- C22C 38/40: with nickel
- C22C 38/42: with copper
- C22C 38/44: with molybdenum or tungsten
- C22C 38/48: with niobium or tantalum
- C23C 16/16: from metal carbonyl compounds
- C21D 9/52: for wires; for strips {; for rods of unlimited length}
- C21D 2251/02: Clad material
- Y10T 428/12458: having composition, density, or hardness gradient
- Y10T 428/12958: Next to Fe-base component
- Y10T 428/12979: Containing more than 10% nonferrous elements [e.g., high alloy, stainless]
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- 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
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A steel wire having a stainless steel exterior; the steel wire includes a core region that comprises at least 55 wt. % iron which is metallurgically bonded to a stainless steel coating that consists of a stainless steel region and a bonding region. The stainless steel region can have a thickness of about 1 μm to about 250 μm, and a stainless steel composition that is approximately consistent across the thickness of the stainless steel region. The stainless steel composition includes an admixture of iron and about 10 wt. % to about 30 wt. % chromium. The bonding region is positioned between the stainless steel region and the core region, has a thickness that is greater than 1 μm and less than the thickness of the stainless steel region, and has a bonding composition. The bonding composition includes an admixture of iron and chromium, with a chromium concentration proximal to the stainless steel region that is approximately equal to the chromium concentration of the stainless steel region and has a chromium concentration proximal to the core region that has less than about 5 wt. % chromium.

## Claims

### Claim 1

A steel tube comprising:
a core region, a bonding region and a stainless steel region;
the core region metallurgically bonded to the stainless steel region by the bonding region; the core region comprising at least 55 wt. % iron;
the stainless steel region having a thickness of about 5 μm to about 250 μm, having a stainless steel composition, the stainless steel composition comprising an admixture of iron and chromium, and the stainless steel composition comprising a chromium concentration of about 10 wt. % to about 30 wt. % that varies by less than 5 wt. %; and
the bonding region positioned between the stainless steel region and the core region, having a thickness that is greater than 5 μm and less than the thickness of the stainless steel region, and having a bonding composition,
the bonding region further having a chromium concentration gradient that decreases from a chromium concentration, proximal to the stainless steel region, that is approximately equal to the chromium concentration of the stainless steel region, to a chromium concentration, proximal to the core region, that is approximately equal to the chromium concentration of the core region.

### Claim 2 (depends on 1)

A steel tube of claim 1, wherein the core region is substantially free of chromium.

### Claim 3 (depends on 1)

A steel tube of claim 1, wherein the core region is a carbon steel having a carbon concentration of less than about 0.5 wt. %.

### Claim 4 (depends on 3)

A steel tube of claim 3, wherein the core region is a carbon steel having a carbon concentration of less than about 0.25 wt. %.

### Claim 5 (depends on 1)

A steel tube of claim 1, wherein the stainless steel region has a thickness of about 10 μm to about 100 μm.

### Claim 6 (depends on 1)

A steel tube of claim 1, wherein the bonding region has a thickness of about 5 μm to about 100 μm.

### Claim 7 (depends on 6)

A steel tube of claim 6, wherein the bonding region has a thickness of about 10 μm to about 50 μm.

### Claim 8 (depends on 1)

A steel tube of claim 1, wherein the stainless steel composition consists of an admixture of iron, chromium, and a transition metal selected from the group consisting of nickel, molybdenum, titanium, niobium, tantalum, vanadium, tungsten, copper, and a mixture thereof.

### Claim 9 (depends on 1)

A steel tube of claim 1, wherein the stainless steel composition consists of an admixture of iron, chromium, and nickel; wherein the stainless steel composition comprises a nickel concentration of about 5 wt. % to about 20 wt. %; and wherein the bonding composition consists essentially of iron, chromium and nickel.

### Claim 10 (depends on 9)

A steel tube of claim 9, wherein the stainless steel composition comprises a chromium concentration of about 16 wt. % to about 25 wt. % and nickel concentration of about 6 wt. % to about 14 wt. %.

### Claim 11 (depends on 9)

A steel tube of claim 9, wherein the stainless steel composition consists essentially of iron, chromium and nickel.

### Claim 12 (depends on 1)

A steel tube of claim 1, wherein the stainless steel composition comprises a chromium concentration of about 10.5 wt. % to about 18 wt. %.

### Claim 13 (depends on 12)

A steel tube of claim 12, wherein the stainless steel composition consists essentially of iron and chromium; and wherein the bonding composition consists essentially of iron and chromium.