Corrosion resistant hardfacing alloy

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.

2. 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.

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

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

5. 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.

6. 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.

7. 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.

8. 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.

9. 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.

10. 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.

11. The work piece 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.

12. The work piece 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.

13. The work piece 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.

14. The work piece of claim 10 , 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.

15. The work piece 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.

16. A work piece having at least a portion of its surfaced covered by a layer, wherein the 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.

17. The work piece of claim 16 , 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.

18. The work piece of claim 16 , 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.

19. The work piece of claim 16 , wherein the work piece is a steel pipe and the layer coats at least a portion of an interior diameter of the pipe.

20. The work piece of claim 16 , 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.

21. The work piece of claim 16 , 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.

22. The work piece of claim 16 , 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.

23. The work piece of claim 16 , 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.