초록 ▼

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 s

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.

대표청구항 ▼

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

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%, andwherein 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%, andwherein the impurities comprise phosphor (P) in an amount in mass % of up to about 0.15% of the total steel composition.