Unbonded flexible pipe

Patent metadata

Field	Value
Publication number	US-10001228-B2
Application number	US-201214125349-A
Country	US
Kind code	B2
Filing date	May 9, 2012
Priority date	Jun 17, 2011
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

The invention relates to an unbonded flexible pipe for offshore applications. The pipe comprises an inner sealing sheath defining a bore and at least one armoring layer comprising metal, wherein the metal of the armoring layer is manganese steel with a composition comprising in mass % of the total steel composition
about 9-30% manganese (Mn)
about 1-4% aluminum (Al)
about 0-6% silicium (Si)
about 0-4% copper (Cu)
about 0-4% nickel (Ni)
about 0-1% carbon (C)
the remainder is iron and impurities.

First claim

What is claimed is:

1. An unbonded flexible pipe for offshore applications, the pipe comprises an inner sealing sheath defining a bore and at least one armoring layer comprising metal, wherein the metal of the armoring layer is manganese steel with a composition comprising in mass % of the total steel composition
about 9-30% manganese (Mn)
about 1-4% aluminum (Al)
about 1-6% silicium (Si)
about 0-4% copper (Cu)
about 0-4% nickel (Ni)
about 0-1% carbon (C)
the remainder is iron and impurities,
wherein the amount of impurities in mass % is up to about 1%, and
wherein the impurities comprise phosphor (P) in an amount in mass % of up to about 0.15% of the total steel composition.

2. An unbonded flexible pipe as claimed in claim 1 , wherein the manganese steel comprises in mass % of the total steel composition
about 12-25% manganese (Mn)
about 1.5-3% aluminum (Al)
about 1.7-4% silicium (Si)
about 0-1% copper (Cu)+nickel (Ni)+0-1% carbon (C)
the remainder is iron and impurities.

3. An unbonded flexible pipe as claimed in claim 1 , wherein the amount of manganese (Mn) in the manganese steel in mass % is about 18-24%.

4. An unbonded flexible pipe as claimed in claim 1 , wherein the total amount of aluminum (Al)+silicium (Si) in the manganese steel in mass % is about 4% or more.

5. An unbonded flexible pipe as claimed in claim 1 , wherein the amount of carbon (C) in the manganese steel in mass % is about 0.1% or less.

6. An unbonded flexible pipe as claimed in claim 1 , wherein the total amount of copper (Cu)+nickel (Ni) in the manganese steel in mass % is about 1% or less.

7. An unbonded flexible pipe as claimed in claim 1 , wherein the impurities comprise boron (B) in an amount in mass % of up to about 0.01% of the total steel composition.

8. An unbonded flexible pipe as claimed in claim 1 , wherein the impurities comprise nitrogen (N) in an amount in mass % of up to about 0.03% of the total steel composition.

9. An unbonded flexible pipe as claimed in claim 1 , wherein the impurities comprise titanium (Ti) in an amount in mass % of up to about 0.15% of the total steel composition.

10. An unbonded flexible pipe as claimed in claim 1 , wherein the impurities comprise niobium (Nb) in an amount in mass % of up to about 0.15% of the total steel composition.

11. An unbonded flexible pipe as claimed in claim 1 , wherein the impurities comprise vanadium (V) in an amount in mass % of up to about 0.15% of the total steel composition.

12. An unbonded flexible pipe as claimed in claim 1 , wherein the impurities comprise chromium (Cr) in an amount in mass % of up to about 0.15% of the total steel composition.

13. An unbonded flexible pipe as claimed in claim 1 , wherein the manganese steel is in the form of at least one wire or strip which is helically wound, the wire is produced by a method comprising hot rolling and/or cold rolling.

14. An unbonded flexible pipe as claimed in claim 1 , wherein the manganese steel is in the form of at least one wire or strip which is helically wound, the wire is produced by a method comprising cold forming.

15. An unbonded flexible pipe as claimed in claim 1 , wherein the manganese steel is in the form of at least one wire or strip which is helically wound, the wire is produced by a method comprising annealing.

16. An unbonded flexible pipe as claimed in claim 1 , wherein the manganese steel is in the form of at least one wire or strip which is helically wound, the wire is produced by a method comprising quenching.

17. An unbonded flexible pipe as claimed in claim 1 , wherein the manganese steel is in the form of at least one wire or strip which is helically wound, the wire is produced by a method comprising patenting.

18. An unbonded flexible pipe as claimed in claim 1 , wherein the manganese steel is in the form of at least one wire or strip which is helically wound, the wire is produced by a method comprising work hardening.

19. An unbonded flexible pipe as claimed in claim 1 , wherein the manganese steel is in the form of at least one wire which is helically wound, the wound wire has an average thickness determined in radial direction of the pipe which is of between about 0.4 and about 20 mm.

20. An unbonded flexible pipe as claimed in claim 1 , wherein the manganese steel is in the form of at least one strip which is folded and mechanically interconnected and which is helically wound.

21. An unbonded flexible pipe as claimed in claim 1 , wherein the at least one armoring layer comprising manganese steel is an inner armoring layer arranged inside the inner sealing sheath or an outer armoring layer arranged outside the inner sealing sheath.

22. An unbonded flexible pipe as claimed in claim 21 , wherein the at least one armoring layer comprising manganese steel is an outer armoring layer arranged outside the inner sealing sheath and wound with an angle to the center axis of the pipe which is about 60° G or less.

23. A method of producing an unbounded flexible pipe, wherein the unbounded flexible pipe comprising at least one unbonded armoring layer and at least one unbonded inner sealing sheath, the method comprising producing the at least one armoring layer using a manganese steel having a composition which comprises in mass % of the total steel composition
about 9-30% manganese (Mn)
about 1-4% aluminum (Al)
about 1-6% silicium (Si)
about 0-4% copper (Cu)
about 0-4% nickel (Ni)
about 0-1% carbon (C)
the remainder is iron and impurities,
wherein the amount of impurities in mass % is up to about 1%, and
wherein the impurities comprise phosphor (P) in an amount in mass % of up to about 0.15% of the total steel composition.

Assignees

• Gundstrup Soeren
• Nat Oilwell Varco Denmark Is

Inventors

• Gundstrup Søren

Classifications

• F16L11/16

  wound from profiled strips or bands · CPC title

• C22C38/12

  containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title

• C21D9/08

  for tubular bodies or pipes · CPC title

• C22C38/08

  containing nickel {(C22C38/105 takes precedence)} · CPC title

• C22C38/02

  containing silicon · CPC title