# US 2015/0147591 A1 · Corrosion resistant hardfacing alloy

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- Number: US 2015/0147591 A1
- Document ID: US20150147591A1
- Status: Published application
- Kind: A1
- Application number: 14/555,245
- Filed: 2014-11-26
- Published: 2015-05-28
- Earliest claimed: 2013-11-26
- Assignees: Scoperta, Inc.
- Applicants: Scoperta, Inc.
- Inventors: Justin Lee Cheney; Shengjun Zhang; John Hamilton Madok; Jonathon Bracci
- Web page: https://patentgrep.com/patent/US20150147591A1

## CPC

- B32B 15/011: {all layers being formed of iron alloys or steels}
- C22C 33/0285: {with Cr, Co, or Ni having a minimum content higher than 5%}
- C22C 37/06: containing chromium
- C22C 37/10: containing aluminium or silicon
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/22: with molybdenum or tungsten
- C22C 38/24: with vanadium
- C22C 38/26: with niobium or tantalum
- C22C 38/28: with titanium or zirconium
- C22C 38/30: with cobalt
- C22C 38/32: with boron
- C23C 4/067: containing free particles of non-metal elements, e.g. carbon, silicon, boron, phosphorus or arsenic
- B22F 3/115: by spraying molten metal, i.e. spray sintering, spray casting
- F16L 57/06: against wear (F16L57/04 takes precedence)
- F16L 58/08: by metal
- Y10T 428/12958: Next to Fe-base component
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- 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)
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Disclosed herein are embodiments of iron-based corrosion resistant hardfacing alloys. The alloys can be designed through the use of different compositional, thermodynamic, microstructural, and performance criteria. In some embodiments, chromium content in the alloy can be increased while avoiding the formation of different hard chromium carbides, thereby increasing the corrosion resistance of the alloy.

## Claims

### Claim 1

A work piece having at least a portion of its surface covered by a layer comprising a microstructure comprising:
an Fe-based matrix comprising ferrite, austenite, martensite or a combination thereof, whereby the matrix contains a minimum of 8 wt. % chromium;
primary hard phases defined as carbides or borides which form 1-20 micron spherical particles at a volume fraction of at least 5%; and
a matrix microhardness of at least 300 Vickers;
wherein the matrix contains less than 10% mole fraction of iron or chromium containing carbide or borocarbide particles in excess of 5 microns in size.

### Claim 2 (depends on 1)

The work piece of claim 1, wherein the matrix does not contain any iron or chromium containing carbide or borocarbide particles in excess of 5 microns in size.

### Claim 3 (depends on 1)

The work piece of claim 1, whereas the layer comprises a grain boundary eutectic boride and/or carbide volume fraction of 10% or more.

### Claim 4 (depends on 1)

The work piece of claim 1, whereas the layer comprises a grain boundary eutectic boride and/or carbide volume fraction of 10% or less.

### Claim 5 (depends on 1)

The work piece of claim 1, wherein the work piece is a steel pipe and the layer coats at least a portion of an interior diameter of the pipe.

### Claim 6 (depends on 1)

The work piece of claim 1, wherein the work piece is a steel plate and the layer coats at least a portion of at least one surface of the steel plate.

### Claim 7 (depends on 1)

The work piece of claim 1, wherein the layer is deposited using one or more of the following techniques: MIG welding, TIG welding, sub-arc welding, open-arc welding, PTA welding, laser cladding, or thermal spraying.

### Claim 8 (depends on 1)

The work piece of claim 1, whereas the layer comprises, in wt.%:
Fe;
B: 0-1;
C: 0.75-1.9;
Co: 0-0.5;
Cr: 12-21;
Mn: 0.5-1.4;
Mo: 0.5-1.6;
Nb: 0.3.5;
Si: 0.5-1.5;
Ti: 0.2-5; and
V: 0-0.6.

### Claim 9 (depends on 1)

The work piece of claim 1, wherein the layer or the feedstock material used to produce the layer comprises in wt.% one or more of the following compositions having Fe and:
C: 1, Co: 0.5, Mn: 0.5, Nb: 0.35, Si: 1.5, Ti: 0.25, V: 0.5;
B: 1, C: 1, Co: 0.5, Cr: 12, Mn: 0.5, Nb: 0.35, Si: 1.5, Ti: 0.25, V: 0.5;
B: 1, C: 1, Co: 0.5, Cr: 12, Mn: 0.5, Mo: 0.5, Nb: 1, Si: 1.5, Ti: 1, V: 0.5;
B: 1, C: 1, Co: 0.5, Cr: 12, Mn: 0.5, Mo: 0.5, Nb: 0.35, Si: 1.5, Ti: 1.8, V: 0.5;
C: 1.9, Cr: 14, Mn: 1.25, Mo: 1, Si: 1, Ti: 5;
B: 0.6, C: 1.2, Cr: 20, Mn: 1, Mo: 1, Nb: 3.5, Si: .0.5, Ti: 0.5, V: 0.5;
B: 0.6, C: 0.8, Cr: 16, Mn: 1, Mo: 1, Nb: 3.5, Si: .0.5, Ti: 0.5, V: 0.5;
B: 0.6, C: 1.6, Cr: 20, Mn: 1, Mo: 1, Nb: 3.5, Si: .0.5, Ti: 0.5, V: 0.5; or
B: 0.6, C: 0.8, Cr: 14.5, Mn: 1, Mo: 1, Nb: 3, Si: 0.5, Ti: 0.5, V: 0.4.

### Claim 10

A method of forming a coated work piece comprising:
depositing a layer on at least a portion of a surface of a work piece, wherein the deposited layer comprises a wear resistant and corrosion resistant alloy, wherein the alloy possesses the following thermodynamic traits:
a minimum weight fraction of chromium in an iron-based austenitic matrix phase calculated at 1300K of at least 8 wt.%;
a minimum mole fraction of isolated hard particles of 5%, wherein isolated hard particles are carbides or borides that form at a temperature above the formation temperature of the austenite or ferrite iron-based matrix phase;
a maximum delta ferrite concentration of 40 mole %, wherein delta ferrite is any the body centered cubic iron-based matrix phase that exists between 1500K and 1900K; and
a maximum of 10 mole % of iron or chromium based (Fe+Cr>50 wt. %) carbides forming at a temperature above the solidus temperature of the alloy.

### Claim 11 (depends on 10)

The method of claim 10, wherein the layer comprises a summed total of grain boundary eutectic carbides and borides, defined as those which form in between the liquidus and solidus of the alloy, of 10 mole % or more.

### Claim 12 (depends on 10)

The method of claim 10, whereas the layer comprises a summed total of grain boundary eutectic carbides and borides, defined as those which form in between the liquidus and solidus of the alloy, of 10 mole % or less.

### Claim 13 (depends on 10)

The method of claim 10, wherein the work piece is a steel pipe and the layer coats at least a portion of an interior diameter of the pipe.

### Claim 14 (depends on 10)

The method of claim 10, wherein the work piece is a steel plate and the layer coats at least a portion of at least one surface of the steel plate.

### Claim 15 (depends on 10)

The method of claim 10, wherein the layer is deposited using one or more of the following techniques: MIG welding, TIG welding, sub-arc welding, open-arc welding, PTA welding, laser cladding, or thermal spraying.

### Claim 16 (depends on 10)

The method of claim 10, wherein the layer comprises in wt. %:
Fe;
B: 0-1;
C: 0.75-1.9;
Co: 0-0.5;
Cr: 12-21;
Mn: 0.5-1.4;
Mo: 0.5-1.6;
Nb: 0.3.5;
Si: 0.5-1.5;
Ti: 0.2-5; and
V: 0-0.6.

### Claim 17 (depends on 10)

The method of claim 10, wherein the layer or the feedstock material used to produce the layer comprises, in wt.%, one or more of the following compositions having Fe and:
C: 1, Co: 0.5, Mn: 0.5, Nb: 0.35, Si: 1.5, Ti: 0.25, V: 0.5;
B: 1, C: 1, Co: 0.5, Cr: 12, Mn: 0.5, Nb: 0.35, Si: 1.5, Ti: 0.25, V: 0.5;
B: 1, C: 1, Co: 0.5, Cr: 12, Mn: 0.5, Mo: 0.5, Nb: 1, Si: 1.5, Ti: 1, V: 0.5;
B: 1, C: 1, Co: 0.5, Cr: 12, Mn: 0.5, Mo: 0.5, Nb: 0.35, Si: 1.5, Ti: 1.8, V: 0.5;
C: 1.9, Cr: 14, Mn: 1.25, Mo: 1, Si: 1, Ti: 5;
B: 0.6, C: 1.2, Cr: 20, Mn: 1, Mo: 1, Nb: 3.5, Si: .0.5, Ti: 0.5, V: 0.5;
B: 0.6, C: 0.8, Cr: 16, Mn: 1, Mo: 1, Nb: 3.5, Si: .0.5, Ti: 0.5, V: 0.5;
B: 0.6, C: 1.6, Cr: 20, Mn: 1, Mo: 1, Nb: 3.5, Si: .0.5, Ti: 0.5, V: 0.5; or
B: 0.6, C: 0.8, Cr: 14.5, Mn: 1, Mo: 1, Nb: 3, Si: 0.5, Ti: 0.5, V: 0.4.

### Claim 18

A work piece having at least a portion of its surface covered by a layer, the layer comprising:
a high wear resistance as defined by an ASTM G65 mass loss of 0.6 grams or less;
a high corrosion resistance as defined by an ASTM G31 corrosion rate in 30,000 ppm saltwater of 10 mils per year or less; and
a high resistance to cracking as defined by the ability to be MIG welded crack free over the entire surface of a 12″×12″ steel plate which is 1″ thick using an interpass temperature of 400° F.

### Claim 19 (depends on 18)

The work piece of claim 18, wherein the work piece is a steel pipe and the layer coats at least a portion of an interior diameter of the pipe.

### Claim 20 (depends on 18)

The work piece of claim 18, wherein the work piece is a steel plate and the layer coats at least a portion of at least one surface of the steel plate.

### Claim 21 (depends on 18)

The work piece of claim 18, wherein the layer is deposited using one or more of the following techniques: MIG welding, TIG welding, sub-arc welding, open-arc welding, PTA welding, laser cladding, or thermal spraying

### Claim 22 (depends on 18)

The work piece of claim 18, whereas the layer comprises in wt. %:
Fe;
B: 0-1;
C: 0.75-1.9;
Co: 0-0.5;
Cr: 12-21;
Mn: 0.5-1.4;
Mo: 0.5-1.6;
Nb: 0.3.5;
Si: 0.5-1.5;
Ti: 0.2-5; and
V: 0-0.6.

### Claim 23 (depends on 18)

The work piece of claim 18, wherein the layer or the feedstock material used to produce the layer comprises, in wt. %, one or more of the following compositions having Fe and:
C: 1, Co: 0.5, Mn: 0.5, Nb: 0.35, Si: 1.5, Ti: 0.25, V: 0.5;
B: 1, C: 1, Co: 0.5, Cr: 12, Mn: 0.5, Nb: 0.35, Si: 1.5, Ti: 0.25, V: 0.5;
B: 1, C: 1, Co: 0.5, Cr: 12, Mn: 0.5, Mo: 0.5, Nb: 1, Si: 1.5, Ti: 1, V: 0.5;
B: 1, C: 1, Co: 0.5, Cr: 12, Mn: 0.5, Mo: 0.5, Nb: 0.35, Si: 1.5, Ti: 1.8, V: 0.5;
C: 1.9, Cr: 14, Mn: 1.25, Mo: 1, Si: 1, Ti: 5;
B: 0.6, C: 1.2, Cr: 20, Mn: 1, Mo: 1, Nb: 3.5, Si: .0.5, Ti: 0.5, V: 0.5;
B: 0.6, C: 0.8, Cr: 16, Mn: 1, Mo: 1, Nb: 3.5, Si: .0.5, Ti: 0.5, V: 0.5;
B: 0.6, C: 1.6, Cr: 20, Mn: 1, Mo: 1, Nb: 3.5, Si: .0.5, Ti: 0.5, V: 0.5; or
B: 0.6, C: 0.8, Cr: 14.5, Mn: 1, Mo: 1, Nb: 3, Si: 0.5, Ti: 0.5, V: 0.4.