Non-magnetic armored steel wire

Abstract

A non-magnetic armored steel wire with a nickel-free double-zinc layer structure is disclosed. The nickel-free double-zinc layer structure includes a first zinc layer electroplated directly onto a substrate and a second zinc or zinc alloy outer layer hot-dip plated onto the first zinc layer, giving the non-magnetic armored steel wire a smooth surface with high fatigue resistance. Marine or submarine three-phase cables armored with the non-magnetic armored steel wire are also disclosed, as well as a method for manufacturing the non-magnetic armored steel wire with the nickel-free double-zinc layer structure and its use in marine or submarine power transmission cables.

Description

Technical Field

[0001] This invention relates to a non-magnetic armored steel wire, its manufacturing method, and its uses, such as as armored steel wire for marine or submarine three-phase cables used for power transmission. Background Technology

[0002] Electricity is a fundamental part of modern life. Electricity transmission is the massive transfer of electrical energy from power plants to distribution centers near demand centers. Transmission lines mostly use high-voltage three-phase alternating current (AC). Electricity is transmitted at high voltages (110kV or higher) to minimize energy loss over long distances. Electricity is typically transmitted via overhead power lines. Underground power transmission has significantly higher costs and greater operational limitations, but is sometimes used in urban or sensitive locations. More recently, submarine cables have offered the possibility of supplying power to small islands or offshore production platforms (which do not generate their own electricity). On the other hand, submarine cables also offer the possibility of transmitting coastal electricity (from wind, waves, ocean currents, etc.) to the mainland.

[0003] These cables are typically steel wire armored cables. A typical structure of a steel wire armored cable 10 is as follows: Figure 1 The conductor 12 is typically made of ordinary stranded copper or aluminum wire. The insulator 14 (e.g., made of cross-linked polyethylene (XLPE)) has good water resistance and excellent insulation properties. The insulator 14 in the cable ensures that the conductor does not come into contact with other metallic materials. The gasket 16 (e.g., made of polyvinyl chloride (PVC) or polyethylene (PE)) provides a protective boundary between the inner and outer layers of the cable. The armor 18 (e.g., made of steel wire) provides mechanical protection, particularly against external impacts. Additionally, the armor wire 18 reduces tension during installation, thus preventing the copper conductor from elongating. An optional sheath 19 (e.g., made of black PVC or PE) holds all components of the cable together and provides additional protection against external stress.

[0004] Patent application CN101950619A discloses an armor structure for high-voltage submarine cables. This armor structure is a ring-shaped hybrid armor layer made of round copper wire and non-magnetic stainless steel wire. The round copper wire and non-magnetic stainless steel wire are arranged alternately. However, the use of two materials complicates the manufacturing process. Furthermore, the use of copper makes this armor structure quite expensive.

[0005] Alternatively, steel wire can be used alone to construct the cable armor structure. However, in existing technologies that use only steel wire to construct cable armor structures, either nickel plating and zinc plating are treated as equivalent alternatives in promoting adhesion without recognizing the mechanical advantages of one over the other, or nickel plating is treated as a mandatory step because the existing technology is biased towards nickel. Nickel plating on stainless steel surfaces is an effective industrial technique for improving zinc adhesion, and the existing technology believes that the absence of nickel will lead to poor adhesion.

[0006] Furthermore, existing technologies focus on addressing adhesion and corrosion resistance issues, but neglect mechanical fatigue resistance, particularly in marine or submarine cable applications. Improving the fatigue life of galvanized stainless steel armored wires used in marine or submarine cable applications while maintaining sufficient corrosion resistance presents a higher-level and urgent technical challenge. Summary of the Invention

[0007] The main objective of this invention is to improve the fatigue life of galvanized stainless steel armored wires used in marine or submarine cable applications while maintaining sufficient corrosion resistance.

[0008] Another object of the present invention is to form a smoother and more uniform outer zinc surface on stainless steel armored wire.

[0009] Another object of the present invention is to apply non-magnetic stainless steel armored wire with a nickel-free double zinc layer structure to the armor structure of marine or submarine cables.

[0010] Another object of the present invention is to provide a non-magnetic stainless steel armored wire structure so as to minimize the magnetic loss of the cable.

[0011] The difference between stainless steel and carbon steel lies in the amount of chromium present. Unprotected carbon steel rusts easily when exposed to air and moisture. Stainless steel contains a sufficient amount of chromium (minimum 10.5 wt%) to form a passivation film of chromium-rich oxides, which prevents further surface corrosion and inhibits corrosion from spreading into the internal structure of the metal. The basic classification of stainless steel has a "ferritic" structure and is magnetic. It is formed by adding chromium and can be hardened by adding carbon (forming them into "martensite"). However, this invention relates to non-magnetic stainless steel, which is "austenitic". Non-magnetic stainless steel has the expected chromium content, and also adds nickel, manganese, and other alloying elements. The addition of "austenitic forming" elements (Ni, Mn, ...) alters the microstructure of the steel and makes it non-magnetic. Non-magnetic stainless steel also contains other components that give austenitic stainless steel excellent properties for various applications.

[0012] Although stainless steel provides corrosion protection due to the instantaneous formation of chromium oxide, this is insufficient for some applications in harsh environments, such as marine or subsea applications. Therefore, an anti-corrosion layer (especially a galvanized layer) is applied to stainless steel wire to further enhance its corrosion protection.

[0013] According to a first aspect of the present invention, a non-magnetic armored steel wire is provided having a nickel-free double zinc layer structure, the nickel-free double zinc layer structure comprising a first zinc layer electroplated directly on a substrate and a second zinc or zinc alloy outer layer hot-dipped onto the first zinc layer, such that the non-magnetic armored steel wire has a smooth surface with high fatigue resistance.

[0014] It has been found that nickel plating on steel surfaces is an effective industrial technique for improving zinc adhesion. Those skilled in the art are more likely to adopt the nickel route because it is a proven and reliable method, and no one has yet recognized any mechanical benefits from removing nickel. The inventors have discovered from a microstructural perspective that when nickel is electroplated onto steel and subsequently hot-dip zinc at 400-500°C, a Ni-Zn intermetallic phase (such as γ-Ni₂Zn) forms at the interface. 11 and δ-Ni3Zn 22 These intermetallic compounds are inherently hard and brittle. Under cyclic bending loads (typically during the installation of marine or submarine cable armor, J-shaped tubing, and wave-induced motion), this brittle interface layer can become the initiation site for fatigue cracks, reducing the fatigue resistance of the steel wire. In contrast, the all-zinc structure of this invention completely avoids the adverse effects of the presence of the Ni-Zn intermetallic phase. The electroplated zinc underlayer provides a tough and metallurgically compatible substrate that adapts to strain without cracking during cyclic bending loads. Therefore, the nickel-free, all-zinc coating structure improves fatigue resistance due to the absence of the brittle Ni-Zn intermetallic phase. The nickel-free, all-zinc coating structure also results in a smoother hot-dip galvanized outer surface through the electroplated zinc underlayer, free from zinc nodules, spots, and uneven wettability, which can occur when zinc is deposited directly on an incompletely activated stainless steel surface or when surface roughness is caused by Ni-Zn phase irregularities. A smooth surface is a characteristic associated with fatigue resistance. Under cyclic loading, surface irregularities can lead to stress concentration, so a smoother surface can further improve fatigue resistance.

[0015] Preferably, the matrix is ​​an austenitic stainless steel matrix or a non-stainless steel austenitic steel matrix.

[0016] The matrix material of non-magnetic armored steel wire can include austenitic stainless steel or non-stainless steel austenitic steel, such as Hadfield or TWIP steel. These types of steel alloys are also difficult to coat by hot-dip galvanizing.

[0017] Preferably, the substrate is surface-activated before being electroplated with the first zinc layer.

[0018] Preferably, the surface activation treatment is photo / electro-assisted pickling.

[0019] Surface activation of steel wire includes any one or more of pickling, atmospheric reduction, and plasma cleaning. When the steel wire surface is activated by pickling, it also includes photo / electro-assisted pickling or a post-pickling fluxing step, where photo / electro-assisted pickling is superior to post-pickling fluxing because pickling alone carries too high a risk of irregular dissolution of the substrate, resulting in excessive roughness. Furthermore, hot-dip galvanizing of non-magnetic steel requires strong pickling + fluxing agent, which results in a rough and irregular surface compared to photo / electro-assisted pickling + electroplating, which produces a lower surface roughness and smaller intermetallic layer. Stainless steel wire can be protected with an inert and / or reducing atmosphere during photo / electro-assisted pickling or post-pickling fluxing.

[0020] When the surface of the steel wire is activated by atmospheric reduction, the steel wire is preferably heated to a temperature in the range of 400°C to 900°C.

[0021] Plasma cleaning includes vacuum and atmospheric plasma cleaning. In vacuum plasma cleaning, a steel wire is placed in a low-pressure (vacuum) tube. Inside the tube or around the wire, ions (such as one or more of Ar+, N2+, He+, and H2+) are activated into plasma by a high voltage between the wire and the tube to remove chromium oxide from the wire surface. The added effect of vacuum plasma cleaning is the accompanying annealing of the wire. In atmospheric plasma cleaning, an ion gun is applied inside a tube, which does not actually require a vacuum. Activated ions are generated in the gun and applied as a cleaning agent to the wire surface.

[0022] Preferably, there is no nickel interlayer between the substrate and the double zinc layer structure, so that there is no nickel-zinc intermetallic phase at the interface.

[0023] Preferably, the maximum thickness of the iron-zinc interlayer in the non-magnetic armored steel wire is 1-3µm.

[0024] Preferably, the thickness of the zinc or zinc alloy in the non-magnetic armored steel wire is less than 100µm.

[0025] In this application, the coating formed on the surface of the stainless steel wire by electroplating and hot-dip galvanizing / zinc alloying is zinc and / or a zinc alloy. The thickness of the double zinc layer structure is less than 100 µm. The zinc-aluminum outer coating has better overall corrosion resistance than zinc. Compared with zinc, the zinc-aluminum outer coating is more temperature resistant. Also, compared with zinc, the zinc-aluminum alloy does not peel off when subjected to high temperatures. The zinc-aluminum outer coating can have an aluminum content ranging from 2 wt% to 23 wt%, for example from 2 wt% to 12 wt%, or for example from 5 wt% to 10 wt%. The preferred composition is in an approximately eutectic position: aluminum is about 5 wt%. The zinc alloy outer coating may also contain a wetting agent, such as lanthanum or cerium, in an amount less than 0.1 wt% of the zinc alloy. The remainder of the outer coating is zinc and unavoidable impurities. Another preferred composition contains about 10 wt% aluminum. This increased aluminum content provides better corrosion protection than a eutectoid composition with about 5 wt% aluminum. Other elements such as silicon and magnesium can be added to the zinc-aluminum coating. More preferably, with regard to optimizing corrosion resistance, particularly good alloys contain 2 wt% to 10 wt% aluminum and 0.2 wt% to 3.0 wt% magnesium, with the remainder being zinc.

[0026] After hot-dip electroplating, wiping or spray wiping can be used to control the coating thickness. The steel wire is then cooled in air, or preferably by means of water. This results in a smoother, more continuous, uniform, and non-porous coating, free from zinc deposits, spots, and uneven wetting.

[0027] Preferably, the stainless steel matrix material of the non-magnetic armored steel wire has an average surface roughness Ra < 1.5µm.

[0028] Preferably, the double zinc layer structure is further coated with an asphalt or organic coating provided by extrusion.

[0029] Applying an additional coating, such as an extruded bitumen or organic coating, to the double-zinc-layer structure of non-magnetic armored steel wire can provide additional protection to the double-zinc-layer structure.

[0030] According to a second aspect of the present invention, a marine or submarine three-phase cable armored with the aforementioned non-magnetic armored steel wire is provided, the cable comprising: three conductors, each conductor comprising a bare copper conductor, a semi-conductive conductor shield wrapped around the bare copper conductor, and an insulating shield wrapped around the conductor shield; a filler, the three conductors being twisted together with the filler by straps; a lead alloy sheath wrapped around the filler; an outer layer covering the lead alloy sheath; and a steel wire armor layer composed of the non-magnetic armored steel wire, the non-magnetic armored steel wire being wound around at least a portion of the marine or submarine three-phase cable.

[0031] Preferably, the marine or submarine three-phase cable has at least one annular armor layer made of the non-magnetic armored steel wire.

[0032] Using the non-magnetic armored steel wire of this invention as armored steel wire in marine or submarine cables significantly extends the cable's service life because the fatigue resistance of the armored steel wire with its nickel-free double zinc layer structure is greatly improved, while maintaining adequate corrosion protection. Furthermore, the "non-magnetic" property of the steel wire according to this invention effectively reduces cable energy loss.

[0033] In a three-phase cable, ideally the sum of the currents flowing through the three conductors is zero. This means that a dedicated return conductor is not required. When, for some reason (such as asymmetrical power generation or dissipation), the sum is not exactly zero, the return current preferably flows through a standard wire armor and / or water barrier, which is typically made of lead or lead alloys, and sometimes copper or aluminum.

[0034] On the other hand, even when the sum of the three-phase currents is zero or close to zero, no magnetic field is required: at a greater distance, such as 10 meters or more away from the cable, the magnetic fields of the three conductors compensate for each other, resulting in very low magnetic field radiation. However, because the armor wires are typically applied quite close to the conductors, we must account for the fact that the magnetic fields radiated by the three individual conductors do not completely compensate for each other at that point. This means that the fluctuating magnetic field strength in the armor is quite high, leading to significant losses in the armor: hysteresis loss and eddy current loss. Therefore, at 50 Hz, hysteresis loss accounts for approximately 90% of the magnetic losses, while eddy current loss accounts for no more than 10%. At higher frequencies, eddy current loss becomes increasingly important relative to hysteresis (at 400 Hz, the two components are approximately equal, but 400 Hz is not typically used for power transmission). Compared to carbon steel, non-magnetic armor materials typically eliminate hysteresis loss completely and significantly reduce eddy current loss.

[0035] A typical 50km long (AC, 150kV, three-phase) cable loses approximately 1.5% of the energy it transmits. Most of the energy is lost in the core conductors (due to their ohmic resistance; power loss = resistance × current). 2 Magnetic loss is typically between 15% and 30% of total cable loss and can be eliminated almost 100% by using non-magnetic armored steel wire, as this does not produce the aforementioned hysteresis effect.

[0036] Preferably, a non-magnetic armored steel wire with a nickel-free double zinc layer structure is combined with a zinc-coated magnetic steel wire to serve as the steel wire armor layer of the marine or submarine three-phase cable.

[0037] Preferably, non-magnetic armored steel wire with a nickel-free double zinc layer structure is combined in parallel with zinc-coated magnetic steel wire.

[0038] In a particular embodiment of the cable according to the invention, it is preferred to combine magnetically armored steel wires and non-magnetically armored steel wires. This combination can be arranged in series or in parallel.

[0039] For a series configuration, this means that along the length of the cable, one section comprises magnetically armored steel wires, and another section, distinct from and following that section, comprises non-magnetically armored steel wires. The section with non-magnetically armored steel wires can be used in locations where the cable is difficult to cool, such as in harbors where the cable may be buried deep. The section with non-magnetically armored steel wires can also be used where the cable must deliver the highest possible power, such as at the junctions of various other cables.

[0040] For parallel configurations, armor layers comprising both non-magnetic and magnetic wires have significantly reduced magnetic losses in the cable. This option may also be more cost-effective than 100% magnetic armor, as magnetic wires imply increased costs. In this regard, a preferred embodiment combines galvanized non-magnetic stainless steel wires with galvanized magnetic low-carbon steel wires. Because both are zinc-coated, one wire is not particularly susceptible to damage from adjacent or neighboring wires in corrosive seabed environments. Examples of this embodiment provide an armor layer alternating between non-magnetic stainless steel and magnetic wires.

[0041] According to a third aspect of the present invention, a method for manufacturing a nonmagnetic armored steel wire having a nickel-free double zinc layer structure is provided, comprising the steps of: (a) directly electroplating a first zinc layer on a substrate; and (b) hot-dip immersing a second zinc or zinc alloy outer layer on the first zinc layer, such that the nonmagnetic armored steel wire has a smooth surface with high fatigue resistance.

[0042] Preferably, the substrate is surface activated before the step of directly electroplating the first zinc layer onto the substrate.

[0043] Preferably, the surface activation treatment is photo / electro-assisted pickling.

[0044] Preferably, after the hot-dip galvanizing of the second zinc or zinc alloy outer layer, an asphalt or organic coating provided by extrusion is applied to the second zinc or zinc alloy outer layer.

[0045] According to a fourth aspect of the invention, the use of non-magnetic armored steel wire in cables for marine or submarine power transmission is provided.

[0046] Therefore, cables include high-voltage, medium-voltage, and low-voltage cables. Currently, common voltage levels used in the medium to high voltage range (e.g., installation point cables for ships or offshore wind farms) are 33kV for installation point cables and 150kV for output cables. These can be extended to 66kV and 220kV respectively. High-voltage cables can also be extended to 280, 320, or 380kV when insulation technology allows for this structure. Because magnetic losses can occur even at low voltage levels, non-magnetic armored steel wire is also suitable for low-voltage cables.

[0047] On the other hand, the cable armored with non-magnetic stainless steel wire according to the present invention can transmit electricity at different frequencies. For example, it can transmit standard AC transmission frequencies, which are 50 Hz in Europe and 60 Hz in North and South America. Moreover, the cable can also be used in transmission systems using 17 Hz (e.g., German Railways) or other frequencies.

[0048] Preferably, the cable is a marine or submarine three-phase cable.

[0049] Preferably, non-magnetic armored steel wire is wound around at least a portion of the marine or submarine three-phase cable.

[0050] Preferably, the marine or submarine three-phase cable has at least one annular armor layer made of non-magnetic armored steel wire.

[0051] Preferably, the armored steel wire is a combination of a non-magnetic armored steel wire with a nickel-free double zinc layer structure and a galvanized magnetic steel wire, used as the armored steel wire for cables used in marine or submarine power transmission.

[0052] Preferably, non-magnetic armored steel wire with a nickel-free double zinc layer structure is combined in parallel with zinc-coated magnetic steel wire.

[0053] Low-carbon steel wire has the following steel composition: carbon content in the range of 0.02 wt% to 0.20 wt%, silicon content in the range of 0.05 wt% to 0.25 wt%, chromium content less than 0.08 wt%, copper content less than 0.25 wt%, manganese content between 0.10 wt% and 0.50 wt%, molybdenum content less than 0.030 wt%, nitrogen content less than 0.015 wt%, nickel content less than 0.10 wt%, phosphorus content less than 0.05 wt%, and sulfur content less than 0.05 wt%.

[0054] The presence of magnetic steel wires in the cable's armor layer has the added advantage of allowing the cable's position to be detected magnetically. Attached Figure Description

[0055] By reading the following specification and appended claims, and referring to the following drawings, various advantages of the embodiments of this disclosure will become apparent to those skilled in the art: Figure 1 It is a high-voltage cable based on existing technology.

[0056] Figure 2 This is a cross-sectional view of a non-magnetic armored steel wire according to the first aspect of the present invention.

[0057] Figure 3 This is a cross-sectional view of a three-phase cable with armored steel wires.

[0058] Figure 4 It displays SEM images and optical microstructure images showing the thickness of the iron-zinc metal interlayer and the full coating. Detailed Implementation

[0059] Figure 2 This is a cross-sectional view of a non-magnetic armored steel wire 20 with a nickel-free double zinc layer structure according to the present invention. The non-magnetic armored steel wire 20 with a nickel-free double zinc layer structure is composed of at least a substrate 22, a first zinc layer 24, and a second zinc or zinc alloy outer layer 26. The first zinc layer 24, which is directly electroplated on the substrate 22, and the second zinc or zinc alloy outer layer 26, which is hot-dip plated on the first zinc layer 24, constitute the nickel-free double zinc layer structure.

[0060] According to one embodiment of the method, steel wires with diameters ranging from 1.0 mm to 10.0 mm are processed.

[0061] The composition (by weight percentage) of the steel wire rod is as follows: C < 0.08; Si < 0.75; Mn ranges from 6.6 to 8; P < 0.045; S < 0.015; N < 0.15; Cr ranges from 15 to 17; Ni ranges from 3.5 to 5; Cu < 2; the remainder is balanced by Fe.

[0062] Depending on the capacity of the production site, steel wire can be processed continuously on one or more production lines.

[0063] The steel wire is first degreased for a few seconds in a degreasing tank (containing phosphoric acid) at a temperature of 30°C to 80°C. An ultrasonic generator is placed in the tank to aid in the degreasing process.

[0064] Alternatively, the steel wire can be degreased for a few seconds in an alkaline degreasing tank (containing NaOH) at 30°C to 80°C. Electrical assistance is applied to the tank to aid in degreasing.

[0065] The subsequent pickling step involves immersing the steel wire in a pickling bath (containing 100-500 g / L sulfuric acid) at 20°C to remove the chromium oxide that forms momentarily. This is followed by another continuous pickling process, in which the steel wire is briefly immersed in the pickling bath (containing 100-500 g / L sulfuric acid) at 20°C to further remove chromium oxide from the surface of the wire. All pickling steps can be assisted by an electric current to ensure adequate activation.

[0066] Following the second pickling step, the steel wire is immediately immersed in an electrolyte bath (containing 10-100 g / L zinc sulfate) at 20°C to 40°C for tens to hundreds of seconds. A first zinc layer 24 is then electroplated directly onto the surface of the steel wire. For zinc plating, an electric charge is applied to the steel wire, attracting zinc ions to bind to the surface. During this step, the steel wire is run at a speed in the range of 20 to 100 m / min, preferably 30 m / min. The steel wire is then rinsed in water to remove excess water.

[0067] The electroplated steel wire is further processed in a fluxing bath. The temperature of the fluxing bath is maintained between 50°C and 90°C, preferably at 70°C. The steel wire is then immersed in a galvanizing bath, which is maintained at a temperature of 400°C to 500°C.

[0068] After electroplating the first zinc layer 24, a second zinc or zinc alloy outer layer 26 is hot-dip plated onto the first zinc layer 24. The second zinc or zinc alloy outer layer 26 may have a different final coating thickness.

[0069] The main features of the armored steel wire with a nickel-free double zinc layer structure according to this embodiment include: 1. Steel wire matrix, non-magnetic austenitic steel, such as austenitic stainless steel; 2. Marine or submarine cable applications; 3. Electroplating the first zinc layer directly onto the steel wire substrate; 4. A second zinc or zinc alloy outer layer is plated onto the first zinc layer by hot-dip immersion. 5. There is no nickel interlayer between the steel wire and the zinc; 6. Smooth, uniform outer surface, free from zinc deposits, spots, etc.; 7. Improved fatigue resistance under marine cyclic loading; 8. There are no nickel-zinc intermetallic compounds at the interface to avoid brittle intermetallic phases.

[0070] As can be seen from the main features of the armored steel wire with the nickel-free double zinc layer structure, the present invention adopts a pure zinc route, excluding any nickel intermediate layer, so that the first zinc layer is directly deposited on the stainless steel substrate, and then the second zinc or zinc alloy outer layer is hot-dip plated. This results in a smoother and more uniform zinc or zinc alloy outer layer surface without brittle nickel-zinc intermetallic phases, and significantly improves the fatigue resistance of ships or seabed industries under cyclic mechanical loads.

[0071] As a note, although steel wires with diameters ranging from 1.0 mm to 10.0 mm are used as intermediate products in the examples, other grades of steel wire or steel wires with larger / smaller diameters can also be used in this invention. It should be understood that, depending on the application, further wire drawing can be applied after galvanizing when it is desirable to increase the tensile strength of the coated steel wire.

[0072] Figure 3 This is a cross-sectional view of a marine or submarine three-phase cable armored with the non-magnetic armored steel wire of the present invention.

[0073] A marine or submarine three-phase cable 30 is shown in the view. It comprises tightly stranded bare copper conductors 31, followed by a semi-conductive conductor shield 32. An insulating shield 33 is used to ensure that the conductors do not come into contact with each other. The insulating conductors are twisted together with filler 34 by straps, followed by a lead alloy sheath 35. The lead alloy sheath 35 is typically required due to the harsh environmental requirements of submarine cables, as well as its compressibility, flexibility, and resistance to moisture and corrosion. The sheath 35 is typically covered by an outer layer 37, which comprises a polyethylene (PE) or polyvinyl chloride (PVC) sheath. This structure is armored by a steel wire armor layer 38. The steel wires used herein will be non-magnetic armored steel wires with a nickel-free double-zinc layer structure for improving fatigue resistance while maintaining sufficient corrosion resistance. An outer sheath 39 (e.g., made of PVC or cross-linked polyethylene (XLPE) or a combination of PVC and XLPE layers) is preferably applied to the outside of the armor layer 38.

[0074] Figure 4 SEM images and optical microstructures of the iron-zinc interlayer and the full coating thickness are shown. Preferably, the maximum thickness of the iron-zinc interlayer of the non-magnetic armored steel wire is 1-3 µm, the thickness of the zinc or zinc alloy is less than 100 µm, and the average surface roughness Ra of the substrate material is <1.5 µm.

[0075] Reference number list 10. Steel wire armored cable 12 conductors 14 Insulators 16 Padding 18 Armor 19 sheath 20 Non-magnetic armored steel wire 22 Matrix 24 First zinc layer 26 Second zinc or zinc alloy outer layer 30 Cable 31 Copper conductor 32 Semiconducting conductor shielding 33 Insulating shielding components 34 Packing 35 Lead alloy sheath 37 Outer Layer 38 steel wire armor layers 39. Outer sheath Those skilled in the art should understand from the foregoing description that the generalized techniques of the embodiments of this disclosure can be implemented in various forms. Therefore, although embodiments of this disclosure have been described in conjunction with specific examples therein, the true scope of the embodiments of this disclosure should not be limited thereto, as other modifications will become apparent to those skilled in the art upon study of the drawings, specification, and claims.

Claims

1. A non-magnetic armored steel wire having a nickel-free double zinc layer structure, the nickel-free double zinc layer structure comprising a first zinc layer electroplated directly on a substrate and a second zinc or zinc alloy outer layer hot-dip plated on the first zinc layer, such that the non-magnetic armored steel wire has a smooth surface with high fatigue resistance.

2. The non-magnetic armored steel wire according to claim 1, wherein, The matrix is ​​an austenitic stainless steel matrix or a non-stainless steel austenitic steel matrix.

3. The non-magnetic armored steel wire according to claim 1 or 2, wherein, The substrate is surface activated before being electroplated with the first zinc layer.

4. The non-magnetic armored steel wire according to claim 3, wherein, The surface activation treatment is photo / electro-assisted pickling.

5. The non-magnetic armored steel wire according to claim 1 or 2, wherein, There is no nickel interlayer between the substrate and the double zinc layer structure, so there are no nickel-zinc intermetallic compounds at the interface.

6. The non-magnetic armored steel wire according to claim 1 or 2, wherein, The maximum thickness of the iron-zinc metal interlayer in the non-magnetic armored steel wire is 1-3µm.

7. The non-magnetic armored steel wire according to claim 1 or 2, wherein, The thickness of the zinc or zinc alloy in the non-magnetic armored steel wire is less than 100µm.

8. The non-magnetic armored steel wire according to claim 1 or 2, wherein, The average surface roughness Ra of the matrix material of the non-magnetic armored steel wire is less than 1.5µm.

9. The non-magnetic armored steel wire according to claim 1 or 2, wherein, The double zinc layer structure is also coated with an asphalt or organic coating provided by extrusion.

10. A marine or submarine three-phase cable armored with non-magnetic armored steel wire according to any one of claims 1 to 9, said cable comprising: Three conductor components, each conductor component including a bare copper conductor, a semi-conductive conductor shield wrapped around the bare copper conductor, and an insulating shield wrapped around the conductor shield; The three conductors are screwed together with the filler by straps; A lead alloy sheath, the lead alloy sheath being wrapped around the filler; An outer layer that covers the lead alloy sheath; and A steel wire armor layer, the steel wire armor layer being composed of the non-magnetic armor steel wire, the non-magnetic armor steel wire being wound around at least a portion of the marine or submarine three-phase cable.

11. The marine or submarine three-phase cable according to claim 10, wherein, The marine or submarine three-phase cable has at least one annular armor layer made of the non-magnetic armored steel wire.

12. The marine or submarine three-phase cable according to claim 10, wherein, Non-magnetic armored steel wire with a nickel-free double zinc layer structure is combined with zinc-coated magnetic steel wire to serve as the steel wire armor layer of the marine or submarine three-phase cable.

13. The marine or submarine three-phase cable according to claim 12, wherein, Non-magnetic armored steel wire with a nickel-free double zinc layer structure is combined in parallel with zinc-coated magnetic steel wire.

14. A method for manufacturing a nonmagnetic armored steel wire having a nickel-free double zinc layer structure, comprising the following steps: (a) Electroplating the first zinc layer directly onto the substrate; (b) A second zinc or zinc alloy outer layer is hot-dip plated on the first zinc layer, so that the non-magnetic armored steel wire has a smooth surface with high fatigue resistance.

15. The method according to claim 14, wherein, The substrate is surface activated before the step of directly electroplating the first zinc layer on the substrate.

16. The method according to claim 15, wherein, The surface activation treatment is photo / electro-assisted pickling.

17. The method according to claim 14 or 15, wherein, After the hot-dip galvanizing of the second zinc or zinc alloy outer layer, an asphalt or organic coating provided by extrusion is applied to the second zinc or zinc alloy outer layer.

18. Use of the nonmagnetic armored steel wire according to any one of claims 1-13 and the nonmagnetic armored steel wire manufactured by the method according to any one of claims 14-17 in marine or submarine power transmission cables.

19. The use of the non-magnetic armored steel wire according to claim 18, wherein, The cable is a three-phase cable.

20. The use of the non-magnetic armored steel wire according to claim 19, wherein, The non-magnetic armored steel wire is wound around at least a portion of the three-phase cable.

21. The use of the non-magnetic armored steel wire according to claim 19, wherein, The three-phase cable has at least one annular armor layer made of the non-magnetic armored steel wire.

22. The use of the non-magnetic armored steel wire according to claim 18, wherein, Non-magnetic armored steel wire with a nickel-free double zinc layer structure is combined with galvanized magnetic steel wire to be used as armored steel wire for cables used in marine or submarine power transmission.

23. The use of the non-magnetic armored steel wire according to claim 22, wherein, Non-magnetic armored steel wire with a nickel-free double zinc layer structure is combined in parallel with zinc-coated magnetic steel wire.

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