Low-stress microbend-resistant wire for fiber optic armor and method of making same

Abstract

The application discloses a low-stress anti-microbending metal wire for optical fiber armoring, which comprises a metal wire body, and semicircular heads arranged at two ends of the metal wire body; the metal wire body comprises a high-strength core layer, a stress buffering intermediate layer and a wear-resistant reinforcing outer layer arranged in sequence from inside to outside; the stress buffering intermediate layer is uniformly coated on the outer surface of the high-strength core layer; and the wear-resistant reinforcing outer layer is uniformly coated on the outer surface of the stress buffering intermediate layer. A preparation method of the low-stress anti-microbending metal wire for optical fiber armoring comprises the following steps: S1, high-strength core layer preparation; S2, stress buffering intermediate layer plating and interface metallurgical combination treatment; S3, internal composite support structure assembly; S4, wear-resistant reinforcing outer layer preparation and surface structure forming; and S5, end forming and finished product post-treatment.

Description

Technical Field

[0001] This invention belongs to the field of optical fiber communication technology, specifically relating to a low-stress, micro-bending resistant metal wire for optical fiber armor and its preparation method. Background Technology

[0002] As fiber optic communication networks develop towards high-density, long-distance, and complex deployment scenarios, the mechanical reliability requirements for fiber optic cables continue to increase. The armor layer, as the core load-bearing protective structure of the cable, is typically composed of multiple spirally twisted metal wires. Its main function is to withstand axial tension, lateral pressure, and external impacts, protecting the internal optical fibers from mechanical damage. Currently, the industry commonly uses ordinary galvanized steel wire or stainless steel wire as armor wire, which has uniform stiffness and is generally rigid. During cable bending deformation, it cannot effectively absorb and disperse stress, and the stress is directly transmitted to the optical fiber along the wire axis. Long-term cyclic bending easily leads to fatigue accumulation, accelerating fiber aging. Furthermore, the smooth surface of conventional armor wires makes it prone to relative slippage between wires and between wires and optical fibers after twisting. In vibration or temperature-changing environments, this results in continuous fretting wear, accompanied by repeated micro-bending impacts, degrading the long-term transmission performance of the optical cable. Therefore, there is an urgent need for a low-stress, micro-bending resistant metal wire for fiber optic armor and its preparation method to solve the above problems. Summary of the Invention

[0003] In view of the problems mentioned in the background art, the purpose of this invention is to provide a low-stress, micro-bending filament for optical fiber armor and its preparation method.

[0004] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: A low-stress, micro-bending resistant metal wire for optical fiber armor includes a metal wire body with semi-circular ends at both ends. The metal wire body includes a high-strength core layer, a stress-buffering intermediate layer, and a wear-resistant reinforcing outer layer arranged sequentially from the inside to the outside. The stress-buffering intermediate layer is uniformly covered on the outer surface of the high-strength core layer, and the wear-resistant reinforcing outer layer is uniformly covered on the outer surface of the stress-buffering intermediate layer.

[0005] Further specifying, the outer surface of the wear-resistant reinforced outer layer is provided with a plurality of arc-shaped stress-dispersing protrusions spaced axially. These arc-shaped stress-dispersing protrusions are evenly arranged on the wear-resistant reinforced outer layer, with equal spacing between adjacent protrusions. An annular stress-relieving groove is provided between two adjacent arc-shaped stress-dispersing protrusions in the wear-resistant reinforced outer layer. This structural design effectively disperses radial loads, releases bending stress, significantly reduces local stress peaks in the wear-resistant reinforced outer layer, and enhances its micro-bending resistance.

[0006] Furthermore, the cross-section of the arc-shaped stress-dispersing protrusion is arranged in an arc shape, the bottom of the annular stress-relieving groove has a smooth arc transition, and the depth of the annular stress-relieving groove is equal to the height of the arc-shaped stress-dispersing protrusion. This structural design eliminates stress concentration at the structural corners, improves the structural fatigue strength, and the fully arc-transitioned surface reduces scratch damage to the optical fiber sheath and adjacent armor wires, improving the safety of the armor assembly process.

[0007] Furthermore, the high-strength core layer is manufactured using either high-strength carbon spring steel wire or high-strength stainless steel wire. This structural design provides core mechanical support for the metal wire, ensuring the armor layer's tensile, impact, and bending resistance, and effectively resisting damage to the internal optical fiber from external mechanical loads.

[0008] Furthermore, the stress-buffered intermediate layer is manufactured using either annealed pure copper or soft aluminum alloy. This structural design effectively buffers and dissipates external impacts and compressive stresses, blocks the direct transmission of stress, significantly reduces the overall stress level of the yarn, and achieves low-stress armoring.

[0009] Furthermore, the wear-resistant reinforced outer layer is manufactured using either austenitic stainless steel or a nickel-based alloy, and its outer surface is provided with a passivation protective film. This structural design significantly improves the wear resistance and environmental corrosion resistance of the yarn.

[0010] Furthermore, a metal bonding transition layer is provided between the high-strength core layer and the stress-buffered intermediate layer. This metal bonding transition layer is either a copper-iron alloy diffusion layer or an aluminum-iron alloy diffusion layer formed by hot-dip galvanizing. This structural design achieves a metallurgical bond between the high-strength core layer and the stress-buffered intermediate layer, significantly improving interlayer bonding strength, preventing interlayer separation and detachment after long-term repeated deformation, and ensuring the functional integrity of the multilayer structure.

[0011] Furthermore, a plurality of uniformly arranged support strips are provided between the stress-buffering intermediate layer and the wear-resistant reinforced outer layer. These support strips are evenly distributed on the intermediate layer, and the other side of each support strip is in pressure contact with the inner wall of the wear-resistant reinforced outer layer. This structural design enhances the radial compressive strength of the yarn and prevents excessive indentation of the wear-resistant reinforced outer layer under load, thus avoiding damage to the stress-buffering intermediate layer and the high-strength core layer.

[0012] Furthermore, a gap layer is provided between the inner wall of the wear-resistant reinforced outer layer and the two adjacent support strips. A corrugated support layer is installed within the gap layer, and the two sides of the corrugated support layer are in abutting contact with the inner wall of the wear-resistant reinforced outer layer and the outer wall of the stress-buffering intermediate layer. This structural design further enhances the radial buffer energy absorption capacity, significantly improves the impact resistance of the yarn, and enhances the micro-bending protection effect.

[0013] A method for preparing a low-stress, micro-bending resistant metal wire for optical fiber armor includes the following steps: S1: High-strength core layer preparation: Select metal wire that meets the mechanical performance requirements as the blank. First, degrease and remove rust from the surface of the blank to remove the surface oxide layer and impurities. Then, through multiple cold drawing processes, the wire is drawn to the preset core layer diameter. Finally, the drawn wire is heat-treated to obtain a high-strength core layer with high tensile strength and high elastic modulus, which serves as the mechanical load-bearing core of the wire. S2: Stress buffer intermediate layer plating and interface metallurgical bonding treatment. The prepared high-strength core layer is pre-treated before plating, and degreasing, pickling activation and fluxing treatment are completed in sequence. Then, a hot-dip plating process is used to immerse the pre-treated high-strength core layer into a molten soft metal plating solution. The immersion temperature and immersion time are precisely controlled to form a stress buffer intermediate layer of uniform thickness on the surface of the high-strength core layer. During the hot-dip plating process, the metal atoms in the high-strength core layer and the plating solution diffuse into each other, forming an alloy diffusion layer with a gradient distribution of metal elements at the interface between the two layers. This achieves metallurgical bonding between the high-strength core layer and the stress buffer intermediate layer, eliminates obvious physical property interfaces, and improves the interlayer bonding strength. S3: The internal composite support structure is assembled. Support bars are uniformly fixed circumferentially on the outer surface of the stress buffer intermediate layer. An annular gap layer is formed between adjacent support bars. A corrugated support layer with the size matching the gap layer is prefabricated. The corrugated support layer is filled and embedded in the gap layer of the adjacent support bars, so that the crests and troughs of the corrugated support layer abut against the side of the support bar and the outer wall of the stress buffer intermediate layer, respectively. Together with the support bars, they form a complementary continuous support system, taking into account both the overall support stiffness and elastic buffering capacity. S4: Preparation of wear-resistant reinforced outer layer and surface structure forming. On the outside of the assembled support structure, a wear-resistant reinforced outer layer is prepared by plating or deposition process, so that the wear-resistant reinforced outer layer completely covers the support strip and the corrugated support layer, forming a dense and continuous outer protective structure. Then, through roll forming process, arc-shaped stress dispersion ridges and annular stress relief grooves are processed on the outer surface of the wear-resistant reinforced outer layer. The forming parameters are controlled to ensure that the arc-shaped ridges have no abrupt changes in the corners and that the bottom of the annular stress relief grooves has a smooth arc transition, so as to avoid the formation of stress concentration points. S5: End forming and post-processing of finished products. The two ends of the processed wire blank are cut, ground and polished to process the wire ends into a semi-circular arc transition shape, completely eliminating the sharp edges at the ends. Finally, the overall wire is dimensionally calibrated and surface finished. Tests are carried out on mechanical properties, morphological accuracy, interlayer bonding force and other items to screen qualified products and obtain the finished low-stress anti-micro-bending metal wire for optical fiber armor.

[0014] The beneficial effects of this invention are as follows: 1. This invention forms a three-tiered mechanical gradient structure of load-bearing, buffering, and protection by sequentially arranging a high-strength core layer, a stress-buffering intermediate layer, and a wear-resistant reinforced outer layer from the inside out. The high-strength core layer, as the core of mechanical load-bearing, bears the main axial tensile force and bending load, providing overall structural stiffness and deformation resistance, ensuring the mechanical protection strength of the armor layer, and can quickly recover through its own elasticity after bending unloading, avoiding permanent deformation. The stress-buffering intermediate layer, as a soft transition phase, with its low elastic modulus and good plastic deformation capacity, bears and disperses the concentrated stress transmitted from the inner and outer layers. It dissipates stress energy through elastic yielding and slight plastic deformation, blocking the direct transmission path of stress and reducing the overall internal stress level of the fiber. Under the synergistic effect of the three, the stress of the fiber can be transmitted, dispersed, and dissolved step by step through the multi-layer structure under bending, lateral pressure, and tension conditions, avoiding the transmission of local stress concentration to the fiber side, effectively suppressing fiber micro-bending loss, reducing the residual stress and fatigue failure risk of the fiber itself, delaying fiber aging, and achieving low-stress, high-reliability fiber armor protection.

[0015] 2. The invention incorporates an arc-shaped stress-dispersing ridge and an annular stress-relieving groove on the outer surface of the metal wire body. The arc-shaped stress-dispersing ridge, as the primary load-bearing structure on the outer side, diffuses concentrated loads acting on the wire surface circumferentially and axially along the arc-shaped convex surface, transforming local point loads into uniformly distributed surface loads. This avoids load concentration on localized areas of the wear-resistant and reinforced outer layer. Simultaneously, the concave-convex structure of the ridge and groove increases the contact friction after the wires are twisted, effectively limiting the relative slippage between wires and between wires and optical fibers. This reduces fretting wear and repeated micro-bending impacts under vibration and temperature alternation environments, ensuring stable long-term transmission performance of the optical cable. Furthermore, the arc-shaped stress-dispersing ridge has no abrupt changes in angle, and the bottom of the annular stress-relieving groove adopts a smooth arc transition, avoiding the stress concentration effect of sharp edges and right-angled groove bottoms. During deformation, stress is uniformly transmitted along the arc surface, which can suppress the initiation and propagation of cracks at the bottom of the groove, improving the fatigue life of the wire.

[0016] 3. The high-strength core layer and stress-buffered intermediate layer of the invention are formed into an alloy diffusion layer through a hot-dip galvanizing process. The metal atoms diffuse into each other to achieve metallurgical bonding. The two metal elements in the diffusion layer are distributed in a gradient, eliminating the obvious physical property interface between the two layers, greatly improving the interlayer bonding strength, and avoiding interlayer delamination failure during service. The inner side of the wear-resistant reinforced outer layer is formed by uniformly arranged support strips and a corrugated support layer filling the gap layer to form a complementary continuous support system. The support strips can uniformly transmit the load borne by the wear-resistant reinforced outer layer to the stress-buffered intermediate layer, avoiding the local load of the wear-resistant reinforced outer layer from directly acting on the buffer intermediate layer and causing local depression. The corrugated support layer can absorb radial impact energy through its own elastic deformation, converting the instantaneous impact load into elastic potential energy and then smoothly transmitting it to the inner stress-buffered intermediate layer, avoiding the impact stress from being directly transmitted to the high-strength core layer and the optical fiber side. Moreover, after the load is removed, it can rely on elastic recovery to maintain the stability of the structural dimensions, further improving the impact resistance and long-term service stability of the wire. Attached Figure Description

[0017] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings; Figure 1 This is a schematic diagram of the axial structure of a low-stress, micro-bending resistant metal wire for optical fiber armor according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the axial cross-sectional structure of a low-stress, micro-bending resistant metal wire for optical fiber armor according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the transverse cross-sectional structure of a low-stress, micro-bending resistant metal wire for optical fiber armor according to an embodiment of the present invention. The symbols for the main components are explained below: 1. Metal wire body; 3. Semi-circular head; 4. High-strength core layer; 5. Stress buffer intermediate layer; 6. Wear-resistant reinforced outer layer; 7. Arc-shaped stress dispersion protrusion; 8. Annular stress relief groove; 9. Metal bonding transition layer; 10. Support strip; 11. Gap layer; 12. Corrugated support layer. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] Example 1, such as Figure 1 , Figure 2 and Figure 3 As shown, a low-stress, micro-bending resistant metal wire for optical fiber armor is provided at both ends of the metal wire body 1. The metal wire body 1 includes a high-strength core layer 4, a stress-buffered intermediate layer 5, and a wear-resistant reinforced outer layer 6 arranged sequentially from the inside to the outside. The stress-buffered intermediate layer 5 is uniformly covered on the outer surface of the high-strength core layer 4, and the wear-resistant reinforced outer layer 6 is uniformly covered on the outer surface of the stress-buffered intermediate layer 5.

[0020] In this embodiment, the semi-circular ends 3 at both ends of the metal wire body 1 adopt an arc transition shape, which not only avoids the wire edges from scratching the optical fiber sheath, but also disperses the edge stress peak when the wire is bent. The metal wire body 1 forms a three-level mechanical gradient system of load-bearing, buffering, and protection through a high-strength core layer 4, a stress-buffering intermediate layer 5, and a wear-resistant reinforced outer layer 6 arranged sequentially from the inside to the outside. The high-strength core layer 4, as the mechanical load-bearing core of the wire, bears the main axial tensile force and bending load, provides overall structural rigidity and deformation resistance, and ensures the mechanical protection strength of the armor layer. The stress-buffering intermediate layer 5, as a soft transition phase, with its low elastic modulus and good plastic deformation capacity, bears and disperses the stress from the high-strength core layer 4 or the stress-buffering intermediate layer 6. The concentrated stress transmitted by the wear-resistant and reinforced outer layer 6 is dissipated through elastic yielding and slight plastic deformation, blocking the direct transmission path of stress and reducing the overall internal stress level of the wire. The wear-resistant and reinforced outer layer 6 is located on the outermost side and directly bears external friction, scratching and environmental erosion, protecting the internal functional layers from external damage and maintaining the stability of the overall structure and dimensions of the wire. Under the synergistic effect of the three, the stress of the metal wire body 1 under bending, lateral pressure and tension conditions can be transmitted, dispersed and eliminated step by step through the multi-layer structure, avoiding the transmission of local stress concentration to the fiber side, effectively suppressing the micro-bending loss of the fiber, and reducing the residual stress and fatigue failure risk of the wire itself, thus achieving low-stress and high-reliability fiber armor protection.

[0021] Example 2, as Figure 1 and Figure 2 As shown, this embodiment adds the following structure based on embodiment 1: the outer surface of the wear-resistant and reinforced outer layer 6 is provided with a number of arc-shaped stress-dispersing protrusions 7 at intervals along the axial direction. The number of arc-shaped stress-dispersing protrusions 7 are evenly arranged on the wear-resistant and reinforced outer layer 6, and the distance between two adjacent arc-shaped stress-dispersing protrusions 7 is equal. The wear-resistant and reinforced outer layer 6 is provided with an annular stress-relieving groove 8 between two adjacent arc-shaped stress-dispersing protrusions 7.

[0022] In this embodiment, when the metal wire body 1 is subjected to radial compression or bending deformation, the arc-shaped stress dispersion ridge 7, as the primary load-bearing structure on the outer side, diffuses the concentrated load acting on the surface of the metal wire body 1 circumferentially and axially along the arc-shaped convex surface, so that the local point load is transformed into a uniform surface load, avoiding the load from being concentrated on the local area of ​​the wear-resistant and reinforced outer layer 6. The annular stress relief groove 8 between adjacent arc-shaped stress dispersion ridges 7 provides a space for the deformation of the outer layer.

[0023] Example 3, as Figure 1 and Figure 2As shown, this embodiment adds the following structure based on embodiment 1: the cross-section of the arc-shaped stress dispersion protrusion 7 is set in an arc shape, the bottom of the annular stress relief groove 8 is a smooth arc transition, and the groove depth of the annular stress relief groove 8 is equal to the height of the arc-shaped stress dispersion protrusion 7.

[0024] In this embodiment, the arc-shaped stress dispersion ridge 7 has no abrupt changes in angle. When the load is applied, the stress is continuously and uniformly transmitted along the arc surface, and no stress concentration point will be formed at the edge position. The bottom of the annular stress relief groove 8 adopts a smooth arc transition, which avoids the stress concentration effect of the right angle groove bottom. During the deformation process, the stress is evenly distributed along the arc groove bottom, which inhibits the initiation and propagation of cracks at the bottom of the groove.

[0025] Example 4, as Figure 2 As shown, this embodiment adds the following structure to the embodiment 1: the high-strength core layer 4 is made of either high-strength carbon spring steel wire or high-strength stainless steel wire.

[0026] In this embodiment, the high-strength core layer 4 bears the main mechanical load of the yarn. When subjected to axial tension, the high-strength core layer 4 bears most of the tensile stress, ensuring that the yarn does not undergo plastic elongation and maintaining the dimensional stability of the armor layer. When subjected to bending deformation, the high-strength core layer 4 provides bending stiffness with its high elastic modulus, limiting the yarn from excessive bending. After the bending is unloaded, it can quickly recover by its own elasticity, avoiding permanent deformation.

[0027] Example 5, as Figure 2 As shown, this embodiment adds the following structure to the embodiment 1: the stress buffer intermediate layer 5 is made of either annealed pure copper or soft aluminum alloy.

[0028] In this embodiment, when the wear-resistant reinforced outer layer 6 is subjected to impact and extrusion loads, the stress buffer intermediate layer 5 absorbs the impact energy through its own elastic yield and slight plastic deformation, transforming the concentrated point load into a uniformly distributed surface load before transferring it to the high-strength core layer 4, thus significantly reducing the stress peak.

[0029] Example 6, as Figure 2 As shown, this embodiment adds the following structure based on embodiment 1: the wear-resistant and reinforced outer layer 6 is made of either austenitic stainless steel or nickel-based alloy, and the outer surface of the wear-resistant and reinforced outer layer 6 is provided with a passivation protective film.

[0030] In this embodiment, the wear-resistant reinforced outer layer 6, as the outermost structure, is in direct contact with the external environment and adjacent armor components. It can resist friction and scratches during laying and service, avoid rapid wear of the surface layer, and withstand corrosive environments such as humidity, acid, alkali, and salt spray, preventing the internal functional layers from being corroded and failing.

[0031] The passivation protective film on the outer surface is a dense metal oxide film layer, which can inhibit the occurrence of electrochemical corrosion and reduce the surface friction coefficient.

[0032] Example 7, as Figure 2 and Figure 3 As shown, this embodiment adds the following structure based on embodiment 1: a metal bonding transition layer 9 is provided between the high-strength core layer 4 and the stress buffer intermediate layer 5. The metal bonding transition layer 9 is either a copper-iron alloy diffusion layer or an aluminum-iron alloy diffusion layer formed by hot-dip plating.

[0033] In this embodiment, the alloy diffusion layer formed by the hot-dip galvanizing process achieves metallurgical bonding between the high-strength core layer 4 and the stress buffer intermediate layer 5 through the mutual diffusion of metal atoms. The two metal elements in the diffusion layer are distributed in a gradient, which eliminates the obvious physical property interface between the high-strength core layer 4 and the stress buffer intermediate layer 5, and can greatly improve the interlayer bonding strength.

[0034] Example 8, as Figure 2 and Figure 3 As shown, this embodiment adds the following structure based on embodiment 1: a plurality of uniformly arranged support strips 10 are provided between the stress buffer intermediate layer 5 and the wear-resistant reinforced outer layer 6. The plurality of support strips 10 are uniformly arranged on the buffer intermediate layer 5, and the other side of the support strips 10 is in contact with the inner wall of the wear-resistant reinforced outer layer 6.

[0035] In this embodiment, the uniformly arranged support bars 10 uniformly transmit the load borne by the wear-resistant reinforced outer layer 6 to the buffer intermediate layer 5, avoiding the local load of the wear-resistant reinforced outer layer 6 from directly acting on the buffer intermediate layer 5 and causing local depressions.

[0036] Example 9, as Figure 2 and Figure 3 As shown, this embodiment adds the following structure based on embodiment 8: a gap layer 11 is provided between the inner wall of the wear-resistant reinforced outer layer 6 and the two adjacent support strips 10, and a corrugated support layer 12 is installed in the gap layer 11. The two sides of the corrugated support layer 12 are in contact with the inner wall of the wear-resistant reinforced outer layer 6 and the outer wall of the stress buffer intermediate layer 5.

[0037] In this embodiment, when the wear-resistant reinforced outer layer 6 is subjected to a radial impact load, the corrugated support layer 12 is compressed first. The corrugated support layer 12 absorbs the impact energy through its own elastic deformation, and the instantaneous impact load is converted into elastic potential energy and then smoothly transmitted to the inner stress buffer intermediate layer 5, avoiding the impact stress from being directly transmitted to the high-strength core layer 4 and the optical fiber side. After the load is removed, the corrugated support layer 12 recovers its original shape by its own elasticity, maintaining the stability of the structural dimensions. The corrugated support layer 12 fills the gap layer 11 of the adjacent support strips 10, forming a complementary continuous support system with the support strips 10. This ensures the overall support stiffness and retains the elastic buffering capacity, preventing the wear-resistant reinforced outer layer 6 from being concave and deformed at the gap layer 11 of the support strips 10.

[0038] A method for preparing a low-stress, micro-bending resistant metal wire for optical fiber armor includes the following steps: S1: High-strength core layer preparation: Select metal wire that meets the mechanical performance requirements as the blank. First, degrease and remove rust from the surface of the blank to remove the surface oxide layer and impurities. Then, through multiple cold drawing processes, the wire is drawn to the preset core layer diameter. Finally, the drawn wire is heat-treated to obtain a high-strength core layer with high tensile strength and high elastic modulus, which serves as the mechanical load-bearing core of the wire. S2: Stress buffer intermediate layer plating and interface metallurgical bonding treatment. The prepared high-strength core layer is pre-treated before plating, and degreasing, pickling activation and fluxing treatment are completed in sequence. Then, a hot-dip plating process is used to immerse the pre-treated high-strength core layer into a molten soft metal plating solution. The immersion temperature and immersion time are precisely controlled to form a stress buffer intermediate layer of uniform thickness on the surface of the high-strength core layer. During the hot-dip plating process, the metal atoms in the high-strength core layer and the plating solution diffuse into each other, forming an alloy diffusion layer with a gradient distribution of metal elements at the interface between the two layers. This achieves metallurgical bonding between the high-strength core layer and the stress buffer intermediate layer, eliminates obvious physical property interfaces, and improves the interlayer bonding strength. S3: The internal composite support structure is assembled. Support bars are uniformly fixed circumferentially on the outer surface of the stress buffer intermediate layer. An annular gap layer is formed between adjacent support bars. A corrugated support layer with the size matching the gap layer is prefabricated. The corrugated support layer is filled and embedded in the gap layer of the adjacent support bars, so that the crests and troughs of the corrugated support layer abut against the side of the support bar and the outer wall of the stress buffer intermediate layer, respectively. Together with the support bars, they form a complementary continuous support system, taking into account both the overall support stiffness and elastic buffering capacity. S4: Preparation of wear-resistant reinforced outer layer and surface structure forming. On the outside of the assembled support structure, a wear-resistant reinforced outer layer is prepared by plating or deposition process, so that the wear-resistant reinforced outer layer completely covers the support strip and the corrugated support layer, forming a dense and continuous outer protective structure. Then, through roll forming process, arc-shaped stress dispersion ridges and annular stress relief grooves are processed on the outer surface of the wear-resistant reinforced outer layer. The forming parameters are controlled to ensure that the arc-shaped ridges have no abrupt changes in the corners and that the bottom of the annular stress relief grooves has a smooth arc transition, so as to avoid the formation of stress concentration points. S5: End forming and post-processing of finished products. The two ends of the processed wire blank are cut, ground and polished to process the wire ends into a semi-circular arc transition shape, completely eliminating the sharp edges at the ends. Finally, the overall wire is dimensionally calibrated and surface finished. Tests are carried out on mechanical properties, morphological accuracy, interlayer bonding force and other items to screen qualified products and obtain the finished low-stress anti-micro-bending metal wire for optical fiber armor.

[0039] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A low-stress, micro-bending resistant metal wire for optical fiber armoring, comprising a metal wire body (1), characterized in that: The metal wire body (1) has semi-circular ends (3) at both ends. The metal wire body (1) includes a high-strength core layer (4), a stress buffer intermediate layer (5) and a wear-resistant reinforced outer layer (6) arranged sequentially from the inside to the outside. The stress buffer intermediate layer (5) is uniformly covered on the outer surface of the high-strength core layer (4), and the wear-resistant reinforced outer layer (6) is uniformly covered on the outer surface of the stress buffer intermediate layer (5).

2. The low-stress, micro-bending resistant metal wire for optical fiber armoring according to claim 1, characterized in that: The outer surface of the wear-resistant reinforced outer layer (6) is provided with a plurality of arc-shaped stress-dispersing protrusions (7) spaced along the axial direction. The plurality of arc-shaped stress-dispersing protrusions (7) are evenly arranged on the wear-resistant reinforced outer layer (6). The distance between two adjacent arc-shaped stress-dispersing protrusions (7) is equal. The wear-resistant reinforced outer layer (6) is provided with an annular stress-relieving groove (8) between two adjacent arc-shaped stress-dispersing protrusions (7).

3. The low-stress, micro-bending resistant metal wire for optical fiber armoring according to claim 2, characterized in that: The cross-section of the arc-shaped stress dispersion protrusion (7) is set in an arc-shaped structure, the bottom of the annular stress relief groove (8) is a smooth arc transition, and the depth of the annular stress relief groove (8) is equal to the height of the arc-shaped stress dispersion protrusion (7).

4. The low-stress, micro-bending resistant metal wire for optical fiber armoring according to claim 3, characterized in that: The high-strength core layer (4) is made of either high-strength carbon spring steel wire or high-strength stainless steel wire.

5. The low-stress, micro-bending resistant metal wire for optical fiber armoring according to claim 4, characterized in that: The stress buffer intermediate layer (5) is made of either annealed pure copper or soft aluminum alloy.

6. The low-stress, micro-bending resistant metal wire for optical fiber armoring according to claim 5, characterized in that: The wear-resistant reinforced outer layer (6) is made of either austenitic stainless steel or nickel-based alloy, and the outer surface of the wear-resistant reinforced outer layer (6) is provided with a passivation protective film.

7. The low-stress, micro-bending resistant metal wire for optical fiber armoring according to claim 6, characterized in that: A metal bonding transition layer (9) is provided between the high-strength core layer (4) and the stress buffer intermediate layer (5). The metal bonding transition layer (9) is either a copper-iron alloy diffusion layer or an aluminum-iron alloy diffusion layer formed by hot-dip plating.

8. The low-stress, micro-bending resistant metal wire for optical fiber armoring according to claim 7, characterized in that: A plurality of uniformly arranged support strips (10) are provided between the stress buffer intermediate layer (5) and the wear-resistant reinforced outer layer (6). The support strips (10) are evenly arranged on the buffer intermediate layer (5), and the other side of the support strips (10) is in contact with the inner wall of the wear-resistant reinforced outer layer (6).

9. A low-stress, micro-bending resistant metal wire for optical fiber armoring according to claim 8, characterized in that: A gap layer (11) is provided between the inner wall of the wear-resistant reinforced outer layer (6) and the two adjacent support strips (10). A corrugated support layer (12) is installed in the gap layer (11). The two sides of the corrugated support layer (12) are in contact with the inner wall of the wear-resistant reinforced outer layer (6) and the outer wall of the stress buffer intermediate layer (5).

10. A method for preparing a low-stress, micro-bending resistant metal wire for optical fiber armor according to any one of claims 1 to 9, characterized in that: Includes the following steps: S1: High-strength core layer preparation: Select metal wire that meets the mechanical performance requirements as the blank. First, degrease and remove rust from the surface of the blank to remove the surface oxide layer and impurities. Then, through multiple cold drawing processes, the wire is drawn to the preset core layer diameter. Finally, the drawn wire is heat-treated to obtain a high-strength core layer with high tensile strength and high elastic modulus, which serves as the mechanical load-bearing core of the wire. S2: Stress buffer intermediate layer plating and interface metallurgical bonding treatment. The prepared high-strength core layer is pre-treated before plating, and degreasing, pickling activation and fluxing treatment are completed in sequence. Then, a hot-dip plating process is used to immerse the pre-treated high-strength core layer into a molten soft metal plating solution. The immersion temperature and immersion time are precisely controlled to form a stress buffer intermediate layer of uniform thickness on the surface of the high-strength core layer. During the hot-dip plating process, the metal atoms in the high-strength core layer and the plating solution diffuse into each other, forming an alloy diffusion layer with a gradient distribution of metal elements at the interface between the two layers. This achieves metallurgical bonding between the high-strength core layer and the stress buffer intermediate layer, eliminates obvious physical property interfaces, and improves the interlayer bonding strength. S3: The internal composite support structure is assembled. Support bars are uniformly fixed circumferentially on the outer surface of the stress buffer intermediate layer. An annular gap layer is formed between adjacent support bars. A corrugated support layer with the size matching the gap layer is prefabricated. The corrugated support layer is filled and embedded in the gap layer of the adjacent support bars, so that the crests and troughs of the corrugated support layer abut against the side of the support bar and the outer wall of the stress buffer intermediate layer, respectively. Together with the support bars, they form a complementary continuous support system, taking into account both the overall support stiffness and elastic buffering capacity. S4: Preparation of wear-resistant reinforced outer layer and surface structure forming. On the outside of the assembled support structure, a wear-resistant reinforced outer layer is prepared by plating or deposition process, so that the wear-resistant reinforced outer layer completely covers the support strip and the corrugated support layer, forming a dense and continuous outer protective structure. Then, through roll forming process, arc-shaped stress dispersion ridges and annular stress relief grooves are processed on the outer surface of the wear-resistant reinforced outer layer. The forming parameters are controlled to ensure that the arc-shaped ridges have no abrupt changes in the corners and that the bottom of the annular stress relief grooves has a smooth arc transition, so as to avoid the formation of stress concentration points. S5: End forming and post-processing of finished products. The two ends of the processed wire blank are cut, ground and polished to process the wire ends into a semi-circular arc transition shape, completely eliminating the sharp edges at the ends. Finally, the overall wire is dimensionally calibrated and surface finished. Tests are carried out on mechanical properties, morphological accuracy, interlayer bonding force and other items to screen qualified products and obtain the finished low-stress anti-micro-bending metal wire for optical fiber armor.

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