Composite ultra-low-carbon weather-resistant fence structural member and preparation method thereof

Abstract

This invention discloses a composite ultra-low carbon weather-resistant protective mesh structure and its preparation method, belonging to the field of steel material processing technology. The protective mesh structure consists of longitudinal wires and horizontal wires with a bottom near-ground distance of <34cm and horizontal wires with a bottom near-ground distance of ≥34cm. The longitudinal wires and horizontal wires with a bottom near-ground distance of <34cm and ≥34cm are manufactured using different chemical compositions and contents. Evaluation is performed using carbon equivalent and corrosion resistance equivalent. The carbon equivalent of the longitudinal wires and horizontal wires with a bottom near-ground distance of <34cm is ≥0.88%, and the corrosion resistance equivalent is ≥2.85%; the carbon equivalent of the horizontal wires with a bottom near-ground distance of ≥34cm is ≥0.61%, and the corrosion resistance equivalent is ≥1.90%. This invention uses different chemical compositions for different protective mesh areas, reducing material costs and avoiding excessive performance.

Description

Technical Field

[0001] This invention relates to the field of steel material processing technology, and more specifically to a composite ultra-low carbon weather-resistant protective mesh structure and its preparation method. Background Technology

[0002] Protective netting structures are widely used in engineering and civil applications such as railways, highways, and basketball courts, with annual consumption reaching millions of tons, indicating a huge demand. Due to my country's variable natural environment, the service environments of protective netting vary considerably, placing stringent requirements on the weather resistance of the steel wire materials under special environments (high temperature, high humidity, high salinity, etc.). Currently, these materials are mainly processed using low-end steel grades such as Q195 and Q235, requiring hot-dip galvanizing to improve the corrosion resistance of the steel wire and extend its service life. However, the hot-dip galvanizing process is costly, costing approximately 800-1200 yuan per ton of steel, and poses a significant environmental pollution risk. Furthermore, hot-dip galvanized materials require intermediate protective treatments such as painting, further increasing operating costs.

[0003] According to professional statistics, corrosion failure of protective netting materials mostly occurs in the bottom area. This is primarily because the steel wires in the bottom area experience greater tensile / compressive stress, and the humidity is also higher compared to the middle and upper levels, significantly increasing the probability of soil electrochemical corrosion and conventional corrosion. Currently, the standard lifespan requirement for protective netting materials is 25 years, with premature and abnormal failure typically occurring in the bottom, near-surface area.

[0004] The service environment of protective wire mesh is varied, and the bottom area is more prone to corrosion. At present, conventional steel wire is often subjected to surface hot-dip galvanizing to improve weather resistance, which has the following disadvantages: 1) Hot-dip galvanizing process is costly; 2) It causes great environmental pollution; 3) Pitting corrosion will form on the surface of hot-dip galvanized material after impact, which increases the corrosion rate; 4) Auxiliary protective treatments such as painting are required in the middle stage, which increases the cost of use. Summary of the Invention

[0005] To address the above problems, this invention provides a composite ultra-low carbon weather-resistant protective netting structure and its manufacturing method. This invention comprehensively considers the failure probability of steel wires in different protective netting areas, classifies the protective netting steel wires into horizontal and vertical wires according to the installation method of the protective netting material, further classifies the horizontal wires according to their height from the ground, and manufactures them using different chemical compositions. This customized design reduces material costs, avoids over-performance, and predicts that the overall protective netting structure will have a service life exceeding 35 years, requiring no auxiliary protection in the medium term, significantly reducing production and maintenance costs, and demonstrating significant economic advantages.

[0006] The first objective of this invention is to provide a composite ultra-low carbon weather-resistant protective net structure, which consists of the following structure: longitudinal wires and transverse wires with a bottom near-ground distance of <34cm, and transverse wires with a bottom near-ground distance of ≥34cm;

[0007] The wire rod for longitudinal wire and transverse wire with a bottom ground distance of <34cm is composed of the following components by mass percentage: C≤0.18%, Si≤0.05%, Mn≤0.08%, P≤0.012%, S≤0.008%, Cu0.25%~0.35%, Cr≥2.55%, Mo≥0.65%, Ni≥0.45%, with the remainder being Fe; carbon equivalent Ceq≥0.88%, corrosion resistance equivalent≥2.85%;

[0008] The wire rod for cross-wires with a bottom ground clearance ≥34cm is composed of the following components by mass percentage: C≤0.15%, Si≤0.05%, Mn≤0.05%, P≤0.012%, S≤0.008%, Cu0.20%~0.30%, Cr≥1.80%, Mo≥0.50%, Ni≥0.21%, with the remainder being Fe; carbon equivalent Ceq≥0.61%, corrosion resistance equivalent≥1.90%;

[0009] The formula for calculating carbon equivalent is: Wherein, C, Mn, Cr, and Mo represent the content of this element;

[0010] The formula for calculating corrosion resistance equivalent is: Corrosion resistance equivalent = Ni + 0.7Cr + 0.5Mo; where Cr, Mo, and Ni are the contents of the elements.

[0011] In one embodiment of the present invention, the wire rod for the longitudinal wire and the transverse wire with a bottom near-ground distance of <34cm is composed of the following components by mass percentage: C 0.16%, Si 0.048%, Mn 0.073%, P 0.01%, S 0.0065%, Cu 0.325%, Cr 2.82%, Mo 0.82%, Ni 0.55%, with the remainder being Fe; and the carbon equivalent Ceq = 0.9%, and the corrosion resistance equivalent = 2.934%.

[0012] The cross wire rod with a bottom ground clearance ≥34cm is composed of the following components by mass percentage: C 0.12%, Si 0.035%, Mn 0.039%, P 0.009%, S 0.0071%, Cu 0.278%, Cr 1.93%, Mo 0.62%, Ni 0.36%, with the remainder being Fe; carbon equivalent Ceq = 0.637%, corrosion resistance equivalent = 2.021%.

[0013] In one embodiment of the present invention, the microstructure of the wire rod for longitudinal wire and transverse wire with a distance of less than 34 cm from the bottom near the ground is equiaxed ferrite with a grain size range of 5.5-7.0, a pearlite ratio of no more than 5.0%, and no abnormal structure. Abnormal structure includes, but is not limited to, bainite and martensite.

[0014] In one embodiment of the present invention, the microstructure of the wire rod for horizontal wire with a bottom near-ground distance ≥34cm is equiaxed ferrite with a grain size range of 6.0-7.5 and no abnormal structures. Abnormal structures include, but are not limited to, pearlite, bainite and martensite.

[0015] The second objective of this invention is to provide a method for preparing the aforementioned composite ultra-low carbon weather-resistant protective mesh structure, comprising the following steps: blast furnace molten iron, desulfurization treatment, converter smelting, LF furnace refining, RH vacuum degassing, argon soft blowing, billet continuous casting, billet full grinding, billet delivery, grinding billet acceptance, high-speed wire rod heating, high-speed wire rod rolling, Stellmor controlled cooling, coiling, P / F line transportation, head and tail shearing and sampling, bundling, and packaging. In the high-speed wire rod heating step, the heating temperature is 1120±30℃, the cross-sectional temperature difference is ≤30℃, the furnace pressure is 25-40MPa, and the time for a 170mm square billet in the furnace is ≥140min, of which the time in the soaking zone is ≥50min.

[0016] In one embodiment of the present invention, in the high-speed wire rolling step, the high-speed wire starting temperature is 1060±30℃; the finishing mill inlet temperature is 900±20℃; the sizing mill inlet temperature is 900±10℃; and the wire drawing temperature is 890±10℃.

[0017] In one embodiment of the present invention, in the Stellmore controlled cooling step, the inlet roller speed is 0.30 m / s, and the roller conveyor throughout the process uses a fixed acceleration range of 1.01.

[0018] In one embodiment of the present invention, in the Stellmore cooling step, when the ambient temperature is >35°C, six insulation covers near the winding port are opened; when the ambient temperature is between 5°C and 35°C, two insulation covers near the winding port are opened; when the ambient temperature is <5°C, all insulation covers are closed.

[0019] In one embodiment of the present invention, during the Stellmore controlled cooling step, the coil temperature is <550°C.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) This invention provides a composite ultra-low carbon weather-resistant protective net structure. The protective net structure uses a weather-resistant component system. By strictly controlling the type and content of the chemical composition of the material and by using an appropriate controlled cooling process, its strength is guaranteed to be within a suitable range and its corrosion resistance is excellent. In the later deep processing, no hot-dip galvanizing treatment is required, which can meet the outdoor use requirements of no coating and no maintenance. While reducing processing costs, it also has environmental advantages.

[0022] (2) According to the installation method of the protective net structure, the protective net structure is divided into horizontal wires and vertical wires; considering that the bottom of the protective net is more prone to abnormal failure near the ground, the horizontal wires are classified according to their height from the ground and manufactured with different chemical components to reduce the cost of protective net materials, avoid performance overkill, significantly reduce production costs, and predict that the overall protective net structure will serve for more than 35 years.

[0023] (3) The composite ultra-low carbon weather-resistant protective net structure provided by the present invention can be used directly without any auxiliary protection in the middle stage. Attached Figure Description

[0024] Figure 1 This is a typical microstructure diagram of the first type of wire rod in Example 1;

[0025] Figure 2 This is a typical microstructure diagram of the second type of wire rod in Example 1. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The existing technology for protective wire mesh often uses hot-dip galvanizing to improve weather resistance. However, hot-dip galvanizing is costly and causes significant environmental pollution. The surface of hot-dip galvanized material is prone to pitting corrosion after impacts, which increases the corrosion rate. Therefore, auxiliary protective treatments such as painting are required in the middle stage, which increases the cost of use.

[0028] Based on this, the present invention provides a composite ultra-low carbon weather-resistant protective net structure. The protective net steel wire material adopts a weather-resistant composition system. By strictly controlling the type and content of the chemical composition of the material and using a suitable controlled cooling process, its strength is ensured to be within a suitable range and its corrosion resistance is excellent. No hot-dip galvanizing treatment is required in the later deep processing, meeting the requirements for outdoor use without coating or maintenance. Furthermore, according to the installation method of the protective net material, the protective net steel wire is divided into horizontal and vertical wires. Considering that abnormal failure is more likely to occur in the near-ground area at the bottom of the protective net, the horizontal wires are classified according to their height from the ground and manufactured using different chemical compositions. This reduces the cost of the protective net material, avoids excessive performance, and predicts that the overall protective net structure will have a service life of over 35 years, requiring no auxiliary protection in the medium term.

[0029] According to the installation area, the steel wire of the protective net is divided into two categories: 1) Category 1, longitudinal wire and horizontal wire in the bottom near-ground area (bottom near-ground distance < 34cm); 2) Category 2, horizontal wire in the middle and high-rise area (bottom near-ground distance ≥ 34cm).

[0030] The composition control range of the wire rods used for the first type of longitudinal wires and the transverse wires in the bottom near-ground area is as follows: C≤0.18%, Si≤0.05%, Mn≤0.08%, P≤0.012%, S≤0.008%, Cu0.25~0.35%, Cr≥2.55%, Mo≥0.65%, Ni≥0.45%, with the remainder being Fe; and the carbon equivalent Ceq≥0.88% (the carbon equivalent formula is: Ceq=C+Mn / 6+(Cr+Mo) / 5), and the corrosion resistance equivalent ≥2.85% (the corrosion resistance equivalent formula is: Ni+0.7Cr+0.5Mo).

[0031] The composition control range for cross-wires in the second-class high-rise area is as follows: C≤0.15%, Si≤0.05%, Mn≤0.05%, P≤0.012%, S≤0.008%, Cu0.20~0.30%, Cr≥1.80%, Mo≥0.50%, Ni≥0.21%, with the remainder being Fe; and the carbon equivalent Ceq≥0.61% (carbon equivalent formula: Ceq=C+Mn / 6+(Cr+Mo) / 5), and the corrosion resistance equivalent ≥1.90% (corrosion resistance equivalent formula: Ni+0.7Cr+0.5Mo).

[0032] Different compositions have varying effects on material strength and corrosion resistance. Carbon is the most effective and economical element for solid solution strengthening, significantly increasing material strength at minimal cost. However, higher strength corresponds to poorer weather resistance; therefore, the carbon content design must strike a balance between strength and corrosion resistance. The contribution of each major strengthening element to strength can be evaluated using the carbon equivalent (Ceq), with the formula: Ceq = C + Mn / 6 + (Cr + Mo) / 5. Regarding corrosion resistance, increasing the addition of alloying elements can accelerate the formation of a thick, dense oxide layer on the material surface, thereby preventing contact between corrosive media and the steel substrate and reducing the corrosion rate of the steel substrate. The contribution of each alloying element to corrosion resistance can be evaluated using the corrosion resistance equivalent formula (Ni + 0.7Cr + 0.5Mo).

[0033] The design principles for the composition of the steel wires are based on their service environment and stress conditions. The longitudinal wires provide support during use and require a certain strength. Furthermore, one end of the longitudinal wire is directly buried in the soil, where corrosion is more severe. Therefore, the longitudinal wires utilize a higher degree of alloying (carbon equivalent and weathering elements) to achieve better strength and weather resistance. While the transverse wires in the bottom near-ground area do not provide support, they are affected by moisture. To ensure strong weather resistance, they also employ a high-alloying approach. To save costs and avoid performance waste, the transverse wires in the middle and upper layers, which have no strength requirements and experience lower environmental corrosion, utilize a low-alloying approach with lower carbon equivalent and weathering element content. Copper can improve the material's corrosion resistance to some extent, but excessive amounts significantly increase brittleness; therefore, there are both upper and lower limits for copper content. Sulfur and phosphorus are harmful elements, and their upper limits are controlled.

[0034] This invention also provides a method for preparing a composite ultra-low carbon weather-resistant protective mesh structure, comprising the following steps:

[0035] The smelting and rolling processes mainly include: blast furnace molten iron → desulfurization treatment → converter smelting → LF furnace refining → RH vacuum degassing → argon soft blowing → continuous casting of square billets (170×170mm) 2 → Billet full over-grinding → Billet delivery → Over-grinding billet acceptance → High-speed wire rod heating → High-speed wire rod rolling → Steyrmo controlled cooling → Coil assembly → P / F line transportation → Head and tail shearing and sampling → Bundling → Packaging.

[0036] The specific steps are as follows:

[0037] Weigh each raw material according to the composition ratio, melt it into molten iron, and then carry out desulfurization treatment to ensure that the sulfur content in the molten iron after treatment is less than 0.040%.

[0038] The molten iron is then smelted in a converter, with the final slag basicity controlled to a target of R≥2.5.

[0039] After the converter smelting is completed, the LF furnace is used for refining. The refining time is ≥30 minutes, and argon gas is purged throughout the process.

[0040] After refining, perform RH vacuum degassing with a vacuum degree ≤100Pa and a vacuum holding time ≥

[0041] 15 minutes.

[0042] Then perform argon soft blowing, with the argon blowing time ≥2min.

[0043] Continuous casting of billets: The target stretching range for a cross-sectional size of 170mm×170mm is 2.0~2.2m / min, and the constant stretching speed is used for ≥95% of the time.

[0044] The square billet is fully re-ground, the steel billet is sent down, and the re-ground billet is inspected.

[0045] In the high-temperature wire rod heating process: the billet heating temperature is 1120±30℃, the cross-sectional temperature difference is ≤30℃, the furnace pressure is maintained at a slightly positive pressure of 25-40MPa, and the 170mm square billet is in the furnace for ≥140min, of which the time in the soaking zone is not less than 50min. Because this material has a high alloy content, the residence time in the soaking zone must be guaranteed, as the high and uniform furnace temperature in the soaking zone ensures sufficient solidification of the alloy material and allows the alloying elements to exert their effects. Since the material's composition is predominantly low-carbon, and the billet shows little decarburization tendency, no upper limit is set for heating time.

[0046] In the high-speed wire rod rolling process: the initial rolling temperature is 1060±30℃; the finishing mill inlet temperature is 900±20℃; the sizing mill inlet temperature is 900±10℃; and the wire drawing temperature is 890±10℃. The wire drawing temperature is a key control indicator for steel rolling and requires precise control. Because this steel contains a certain amount of chromium and molybdenum, which increases the hardenability of the material, the wire drawing temperature must not be too high. Otherwise, during subsequent cooling, excessively high material temperatures can lead to localized rapid cooling, resulting in abnormal structures such as martensite and bainite.

[0047] The Steyrmo controlled cooling process is as follows: The wire rod undergoes slow cooling on the Steyrmo air-cooling line. The inlet roller speed is 0.30 m / s, and the entire roller conveyor uses a fixed acceleration range of 1.01. The overlap points are not fixed to reduce the difference between coils. All fans on the Steyrmo roller conveyor are turned off, eliminating the need for air cooling and ensuring sufficient ferrite transformation. Based on changes in ambient temperature, the opening status of the insulation covers is adjusted to ensure the wire rod coiling temperature remains below 550℃. This prevents self-tempering of the wire rod due to excessively high coiling temperature, which would result in an excessively thick iron oxide scale that is prone to peeling, ultimately affecting the surface weather resistance. When the ambient temperature is above 35℃, the six insulation covers near the coiling opening are opened; when the ambient temperature ranges from 5℃ to 35℃, the two insulation covers near the coiling opening are opened; when the ambient temperature is below 5℃, all insulation covers are closed. After the wire rod is air-cooled to room temperature, it is coiled, transported on the P / F line, cut at both ends and sampled, bundled and packaged.

[0048] Example 1

[0049] This embodiment provides a composite ultra-low carbon weather-resistant protective net structure, including a type 1 steel wire material and a type 2 steel wire material.

[0050] Class 1 steel wire materials: Wire rods for longitudinal wires and transverse wires with a bottom ground distance of <34cm are composed of the following components by weight percentage:

[0051] The composition is: C 0.16%, Si 0.048%, Mn 0.073%, P 0.01%, S 0.0065%, Cu 0.325%, Cr 2.82%, Mo 0.82%, Ni 0.55%, with the remainder being Fe; and the carbon equivalent Ceq = 0.900%, and the corrosion resistance equivalent = 2.934%.

[0052] Class 2 steel wire materials: Wire rods for cross wires with a bottom ground clearance ≥34cm are composed of the following components by mass percentage: C 0.12%, Si 0.035%, Mn 0.039%, P 0.009%, S 0.0071%, Cu 0.278%, Cr 1.93%, Mo 0.62%, Ni 0.36%, with the remainder being Fe; carbon equivalent Ceq = 0.637%, corrosion resistance equivalent = 2.021%.

[0053] Type 1 and Type 2 steel wire materials are prepared according to the following steps:

[0054] (1) Weigh each raw material according to the mass percentage of each type of steel wire material, melt it into molten iron, and then carry out desulfurization treatment to ensure that the sulfur content in the molten iron after treatment is less than 0.040%.

[0055] (2) Then the molten iron is smelted in a converter, and the final slag basicity is controlled to target R≥2.5;

[0056] (3) After the converter smelting is completed, LF furnace refining is carried out. The refining time is ≥30min, and argon gas is blown throughout the process.

[0057] (4) After refining, perform RH vacuum degassing with a vacuum degree ≤100pa and a vacuum holding time ≥15min.

[0058] (5) Then perform argon soft blowing, and the argon soft blowing time is ≥2min.

[0059] (6) Continuous casting of billets: The target stretching range for a cross-sectional size of 170mm×170mm is 2.0~2.2m / min, and the constant stretching speed is used for ≥95% of the time.

[0060] (7) The billet is fully re-ground, the steel billet is sent down, and the re-ground billet is inspected.

[0061] (8) In the high-strength wire rod heating step: the billet heating temperature is 1095℃, the cross-sectional temperature difference is 20℃, the furnace pressure is maintained at 30MPa, and the 170 square billet is in the furnace for 155min, of which the time in the soaking section is 52min.

[0062] (9) In the high wire rolling process: the high wire opening temperature is 1053℃; the finishing mill inlet temperature is 915℃; the sizing mill inlet temperature is 904℃; and the wire drawing temperature is 885℃.

[0063] (10) The Stellmore controlled cooling process is as follows: the wire rod undergoes slow cooling on the Stellmore air-cooling line. The inlet roller speed is 0.30 m / s, and the entire roller conveyor uses a fixed acceleration range of 1.01. The overlap point is not fixed to reduce the difference between the same rolls. The fans on the Stellmore roller conveyor are all in the off state, and no air cooling treatment is required to ensure that the microstructure fully completes the ferrite transformation. When the ambient temperature is 21℃, the two heat-insulating covers near the coiling opening are opened. The wire rod coiling temperature is 539℃.

[0064] (11) After the wire rod is air-cooled to room temperature, it is coiled, transported on the P / F line, cut at the beginning and end and sampled, bundled and packaged.

[0065] Example 2

[0066] This embodiment provides a composite ultra-low carbon weather-resistant protective net structure, including a type 1 steel wire material and a type 2 steel wire material.

[0067] Class 1 steel wire materials: Wire rods for longitudinal wires and transverse wires with a bottom ground distance of <34cm are composed of the following components by weight percentage:

[0068] The composition is: C 0.13%, Si 0.033%, Mn 0.066%, P 0.011%, S 0.0065%, Cu 0.298%, Cr 2.92%, Mo 0.93%, Ni 0.63%, with the remainder being Fe; and the carbon equivalent Ceq = 0.911%, and the corrosion resistance equivalent = 3.139%.

[0069] Class 2 steel wire materials: Wire rods for cross wires with a bottom ground clearance ≥34cm are composed of the following components by weight percentage:

[0070] Composition: C 0.09%, Si 0.041%, Mn 0.043%, P 0.008%, S 0.0072%, Cu 0.264%, Cr 2.05%, Mo 0.79%, Ni 0.29%, with the remainder being Fe; carbon equivalent Ceq ≥ 0.665, corrosion resistance equivalent = 2.120%.

[0071] Type 1 and Type 2 steel wire materials are prepared according to the following steps:

[0072] (1) Weigh each raw material according to the mass percentage of each type of steel wire material, melt it into molten iron, and then carry out desulfurization treatment to ensure that the sulfur content in the molten iron after treatment is less than 0.040%.

[0073] (2) Then the molten iron is smelted in a converter, and the final slag basicity is controlled to target R≥2.5;

[0074] (3) After the converter smelting is completed, LF furnace refining is carried out. The refining time is ≥30min, and argon gas is blown throughout the process.

[0075] (4) After refining, perform RH vacuum degassing with a vacuum degree ≤100pa and a vacuum holding time ≥15min.

[0076] (5) Then perform argon soft blowing, and the argon soft blowing time is ≥2min.

[0077] (6) Continuous casting of billets: The target stretching range for a cross-sectional size of 170mm×170mm is 2.0~2.2m / min, and the constant stretching speed is used for ≥95% of the time.

[0078] (7) The billet is fully re-ground, the steel billet is sent down, and the re-ground billet is inspected.

[0079] (8) In the high-strength wire rod heating step: the billet heating temperature is 1115℃, the cross-sectional temperature difference is 18℃, the furnace pressure is maintained at 30MPa, and the 170 square billet is in the furnace for 148 minutes, of which the time in the soaking section is 49 minutes.

[0080] (9) In the high wire rolling process: the high wire opening temperature is 1067℃; the finishing mill inlet temperature is 922℃; the sizing mill inlet temperature is 909℃; and the wire drawing temperature is 889℃.

[0081] (10) The Stellmore controlled cooling process is as follows: the wire rod undergoes slow cooling on the Stellmore air-cooling line. The inlet roller speed is 0.30 m / s, and the entire roller conveyor uses a fixed acceleration range of 1.01. The overlap point is not fixed to reduce the difference between the same rolls. The fans on the Stellmore roller conveyor are all in the off state, and no air cooling treatment is required to ensure that the microstructure fully completes the ferrite transformation. When the ambient temperature is -2℃, the insulation cover near the coiling opening is not opened. The wire rod coiling temperature is 541℃.

[0082] (11) After the wire rod is air-cooled to room temperature, it is coiled, transported on the P / F line, cut at the beginning and end and sampled, bundled and packaged.

[0083] Example 3

[0084] This embodiment provides a composite ultra-low carbon weather-resistant protective net structure, including a type 1 steel wire material and a type 2 steel wire material.

[0085] Class 1 steel wire materials: Wire rods for longitudinal wires and transverse wires with a bottom ground distance of <34cm are composed of the following components by weight percentage:

[0086] The composition is: C 0.14%, Si 0.039%, Mn 0.07%, P 0.009%, S 0.0058%, Cu 0.302%, Cr 3.16%, Mo 1.03%, Ni 0.77%, with the remainder being Fe; and the carbon equivalent Ceq = 0.990%, and the corrosion resistance equivalent = 3.497%.

[0087] Class 2 steel wire materials: Wire rods for cross wires with a bottom ground clearance ≥34cm are composed of the following components by weight percentage:

[0088] Composition: C 0.11%, Si 0.042%, Mn 0.039%, P 0.008%, S 0.0062%, Cu 0.229%, Cr 1.98%, Mo 0.85%, Ni 0.23%, with the remainder being Fe; carbon equivalent Ceq = 0.683%, corrosion resistance equivalent = 2.041%.

[0089] Type 1 and Type 2 steel wire materials are prepared according to the following steps:

[0090] (1) Weigh each raw material according to the mass percentage of each type of steel wire material, melt it into molten iron, and then carry out desulfurization treatment to ensure that the sulfur content in the molten iron after treatment is less than 0.040%.

[0091] (2) Then the molten iron is smelted in a converter, and the final slag basicity is controlled to target R≥2.5;

[0092] (3) After the converter smelting is completed, LF furnace refining is carried out. The refining time is ≥30min, and argon gas is blown throughout the process.

[0093] (4) After refining, perform RH vacuum degassing with a vacuum degree ≤100pa and a vacuum holding time ≥15min.

[0094] (5) Then perform argon soft blowing, and the argon soft blowing time is ≥2min.

[0095] (6) Continuous casting of billets: The target stretching range for a cross-sectional size of 170mm×170mm is 2.0~2.2m / min, and the constant stretching speed is used for ≥95% of the time.

[0096] (7) The billet is fully re-ground, the steel billet is sent down, and the re-ground billet is inspected.

[0097] (8) In the high-strength wire rod heating step: the billet heating temperature is 1125℃, the cross-sectional temperature difference is 15℃, the furnace pressure is maintained at 30MPa, and the 170 square billet is in the furnace for 150min, of which the time in the soaking section is 51min.

[0098] (9) In the high wire rolling process: the high wire opening temperature is 1069℃; the finishing mill inlet temperature is 921℃; the sizing mill inlet temperature is 896℃; and the wire drawing temperature is 882℃.

[0099] (10) The Stellmore controlled cooling process is as follows: The wire rod undergoes slow cooling on the Stellmore air-cooling line. The inlet roller speed is 0.30 m / s, and the entire roller conveyor uses a fixed acceleration range of 1.01. The overlap point is not fixed to reduce the difference between the same rolls. The fans on the Stellmore roller conveyor are all in the off state, and no air cooling treatment is required to ensure that the microstructure fully completes the ferrite transformation. When the ambient temperature is 5℃, the two heat-insulating covers near the coiling opening are opened. The wire rod coiling temperature is 522℃.

[0100] (11) After the wire rod is air-cooled to room temperature, it is coiled, transported on the P / F line, cut at the beginning and end and sampled, bundled and packaged.

[0101] Example 4

[0102] This embodiment provides a composite ultra-low carbon weather-resistant protective mesh structure, including a type 1 steel wire material and a type 2 steel wire material.

[0103] Class 1 steel wire materials: Wire rods for longitudinal wires and transverse wires with a bottom ground distance of <34cm are composed of the following components by weight percentage:

[0104] The composition is: C 0.17%, Si 0.041%, Mn 0.069%, P 0.01%, S 0.0077%, Cu 0.296%, Cr 2.84%, Mo 0.78%, Ni 0.72%, with the remainder being Fe; and the carbon equivalent Ceq = 0.906%, and the corrosion resistance equivalent = 3.098%.

[0105] Class 2 steel wire materials: Wire rods for cross wires with a bottom ground clearance ≥34cm are composed of the following components by weight percentage:

[0106] Composition: C 0.12%, Si 0.038%, Mn 0.041%, P 0.009%, S 0.0049%, Cu 0.257%, Cr 2.36%, Mo 0.81%, Ni 0.43%, with the remainder being Fe; carbon equivalent Ceq = 0.761%, corrosion resistance equivalent = 2.487%.

[0107] Type 1 and Type 2 steel wire materials are prepared according to the following steps:

[0108] (1) Weigh each raw material according to the mass percentage of each type of steel wire material, melt it into molten iron, and then carry out desulfurization treatment to ensure that the sulfur content in the molten iron after treatment is less than 0.040%.

[0109] (2) Then the molten iron is smelted in a converter, and the final slag basicity is controlled to target R≥2.5;

[0110] (3) After the converter smelting is completed, LF furnace refining is carried out. The refining time is ≥30min, and argon gas is blown throughout the process.

[0111] (4) After refining, perform RH vacuum degassing with a vacuum degree ≤100pa and a vacuum holding time ≥15min.

[0112] (5) Then perform argon soft blowing, and the argon soft blowing time is ≥2min.

[0113] (6) Continuous casting of billets: The target stretching range for a cross-sectional size of 170mm×170mm is 2.0~2.2m / min, and the constant stretching speed is used for ≥95% of the time.

[0114] (7) The billet is fully re-ground, the steel billet is sent down, and the re-ground billet is inspected.

[0115] (8) In the high-strength wire rod heating step: the billet heating temperature is 1090℃, the cross-sectional temperature difference is 23℃, the furnace pressure is maintained at 30MPa, and the 170 square billet is in the furnace for 146 minutes, of which the time in the soaking section is 56 minutes.

[0116] (9) In the high wire rolling process: the high wire opening temperature is 1065℃; the finishing mill inlet temperature is 918℃; the sizing mill inlet temperature is 905℃; and the wire drawing temperature is 876℃.

[0117] (10) The Stellmore controlled cooling process is as follows: the wire rod undergoes slow cooling on the Stellmore air-cooling line. The inlet roller speed is 0.30 m / s, and the entire roller conveyor uses a fixed acceleration range of 1.01. The overlap point is not fixed to reduce the difference between the same rolls. The fans on the Stellmore roller conveyor are all in the off state, and no air cooling treatment is required to ensure that the microstructure fully completes the ferrite transformation. When the ambient temperature is 39℃, the 6 heat insulation covers near the coiling opening are opened. The wire rod coiling temperature is 533℃.

[0118] (11) After the wire rod is air-cooled to room temperature, it is coiled, transported on the P / F line, cut at the beginning and end and sampled, bundled and packaged.

[0119] Example 5

[0120] This embodiment provides a composite ultra-low carbon weather-resistant protective net structure, including a type 1 steel wire material and a type 2 steel wire material.

[0121] Class 1 steel wire materials: Wire rods for longitudinal wires and transverse wires with a bottom ground distance of <34cm are composed of the following components by weight percentage:

[0122] Composition: C 0.18%, Si 0.048%, Mn 0.08%, P 0.012%, S 0.0065%, Cu 0.25%, Cr 2.55%, Mo 1.24%, Ni 0.45%, with the remainder being Fe. Carbon equivalent Ceq = 0.951%, corrosion resistance equivalent = 2.855%.

[0123] Class 2 steel wire materials: Wire rods for cross wires with a bottom ground clearance ≥34cm are composed of the following components by weight percentage:

[0124] Composition: C 0.12%, Si 0.05%, Mn 0.032%, P 0.012%, S 0.0075%, Cu 0.3%, Cr 1.80%, Mo 0.87%, Ni 0.21%, with the remainder being Fe. Carbon equivalent (Ceq) = 0.659%, corrosion resistance equivalent (Ceq) = 1.905%.

[0125] Type 1 and Type 2 steel wire materials are prepared according to the following steps:

[0126] (1) Weigh each raw material according to the mass percentage of each type of steel wire material, melt it into molten iron, and then carry out desulfurization treatment to ensure that the sulfur content in the molten iron after treatment is less than 0.040%.

[0127] (2) Then the molten iron is smelted in a converter, and the final slag basicity is controlled to target R≥2.5;

[0128] (3) After the converter smelting is completed, LF furnace refining is carried out. The refining time is ≥30min, and argon gas is blown throughout the process.

[0129] (4) After refining, perform RH vacuum degassing with a vacuum degree ≤100pa and a vacuum holding time ≥15min.

[0130] (5) Then perform argon soft blowing, and the argon soft blowing time is ≥2min.

[0131] (6) Continuous casting of billets: The target stretching range for a cross-sectional size of 170mm×170mm is 2.0~2.2m / min, and the constant stretching speed is used for ≥95% of the time.

[0132] (7) The billet is fully re-ground, the steel billet is sent down, and the re-ground billet is inspected.

[0133] (8) In the high-strength wire rod heating step: the billet heating temperature is 1150℃, the cross-sectional temperature difference is 20℃, the furnace pressure is maintained at 25MPa, and the 170 square billet is in the furnace for 160min, of which the time in the soaking section is 54min.

[0134] (9) In the high wire rolling process: the high wire opening temperature is 1090℃; the finishing mill inlet temperature is 920℃; the sizing mill inlet temperature is 910℃; and the wire drawing temperature is 900℃.

[0135] (10) The Stellmore controlled cooling process is as follows: the wire rod undergoes slow cooling on the Stellmore air-cooling line. The inlet roller speed is 0.30 m / s, and the entire roller conveyor uses a fixed acceleration range of 1.01. The overlap point is not fixed to reduce the difference between the same rolls. The fans on the Stellmore roller conveyor are all in the off state, and no air cooling treatment is required to ensure that the microstructure fully completes the ferrite transformation. When the ambient temperature is 21℃, the two heat-insulating covers near the coiling opening are opened. The wire rod coiling temperature is 539℃.

[0136] (11) After the wire rod is air-cooled to room temperature, it is coiled, transported on the P / F line, cut at the beginning and end and sampled, bundled and packaged.

[0137] Example 6

[0138] This embodiment provides a composite ultra-low carbon weather-resistant protective net structure, including a type 1 steel wire material and a type 2 steel wire material.

[0139] Class 1 steel wire materials: Wire rods for longitudinal wires and transverse wires with a bottom ground distance of <34cm are composed of the following components by weight percentage:

[0140] Composition: C 0.17%, Si 0.05%, Mn 0.07%, P 0.011%, S 0.008%, Cu 0.35%, Cr 3.01%, Mo 0.65%, Ni 0.45%, with the remainder being Fe. Carbon equivalent Ceq = 0.914%, corrosion resistance equivalent = 2.882%.

[0141] Class 2 steel wire materials: Wire rods for cross wires with a bottom ground clearance ≥34cm are composed of the following components by weight percentage:

[0142] Composition: C 0.15%, Si 0.04%, Mn 0.05%, P 0.009%, S 0.008%, Cu 0.2%, Cr 1.93%, Mo 0.50%, Ni 0.37%, with the remainder being Fe. Carbon equivalent (Ceq) = 0.644%, corrosion resistance equivalent (Ceq) = 1.971%.

[0143] Type 1 and Type 2 steel wire materials are prepared according to the following steps:

[0144] (1) Weigh each raw material according to the mass percentage of each type of steel wire material, melt it into molten iron, and then carry out desulfurization treatment to ensure that the sulfur content in the molten iron after treatment is less than 0.040%.

[0145] (2) Then the molten iron is smelted in a converter, and the final slag basicity is controlled to target R≥2.5;

[0146] (3) After the converter smelting is completed, LF furnace refining is carried out. The refining time is ≥30min, and argon gas is blown throughout the process.

[0147] (4) After refining, perform RH vacuum degassing with a vacuum degree ≤100pa and a vacuum holding time ≥15min.

[0148] (5) Then perform argon soft blowing, and the argon soft blowing time is ≥2min.

[0149] (6) Continuous casting of billets: The target stretching range for a cross-sectional size of 170mm×170mm is 2.0~2.2m / min, and the constant stretching speed is used for ≥95% of the time.

[0150] (7) The billet is fully re-ground, the steel billet is sent down, and the re-ground billet is inspected.

[0151] (8) In the high-strength wire rod heating step: the billet heating temperature is 1090℃, the cross-sectional temperature difference is 20℃, the furnace pressure is maintained at 40MPa, and the 170 square billet is in the furnace for 155min, of which the time in the soaking section is 52min.

[0152] (9) In the high wire rolling process: the high wire opening temperature is 1030℃; the finishing mill inlet temperature is 880℃; the sizing mill inlet temperature is 890℃; and the wire drawing temperature is 880℃.

[0153] (10) The Stellmore controlled cooling process is as follows: the wire rod undergoes slow cooling on the Stellmore air-cooling line. The inlet roller speed is 0.30 m / s, and the entire roller conveyor uses a fixed acceleration range of 1.01. The overlap point is not fixed to reduce the difference between the same rolls. The fans on the Stellmore roller conveyor are all in the off state, and no air cooling treatment is required to ensure that the microstructure fully completes the ferrite transformation. When the ambient temperature is 21℃, the two heat-insulating covers near the coiling opening are opened. The wire rod coiling temperature is 539℃.

[0154] (11) After the wire rod is air-cooled to room temperature, it is coiled, transported on the P / F line, cut at the beginning and end and sampled, bundled and packaged.

[0155] Comparative Example 1

[0156] This comparative example provides a composite ultra-low carbon weather-resistant protective mesh structure, including Class 1 steel wire material and Class 2 steel wire material.

[0157] Class 1 steel wire materials: Wire rods for longitudinal wires and transverse wires with a bottom ground distance of <34cm are composed of the following components by weight percentage:

[0158] The composition is: C 0.19%, Si 0.043%, Mn 0.071%, P 0.012%, S 0.0062%, Cu 0.321%, Cr 3.03%, Mo 0.71%, Ni 0.70%, with the remainder being Fe; and the carbon equivalent Ceq = 0.950%, and the corrosion resistance equivalent = 3.176%.

[0159] Class 2 steel wire materials: Wire rods for cross wires with a bottom ground clearance ≥34cm are composed of the following components by weight percentage:

[0160] Composition: C 0.13%, Si 0.031%, Mn 0.031%, P 0.007%, S 0.0072%, Cu 0.213%, Cr 1.91%, Mo 0.45%, Ni 0.22%, with the remainder being Fe; carbon equivalent Ceq = 0.607%, corrosion resistance equivalent = 1.782%.

[0161] Type 1 and Type 2 steel wire materials are prepared according to the following steps:

[0162] (1) Weigh each raw material according to the mass percentage of each type of steel wire material, melt it into molten iron, and then carry out desulfurization treatment to ensure that the sulfur content in the molten iron after treatment is less than 0.040%.

[0163] (2) Then the molten iron is smelted in a converter, and the final slag basicity is controlled to target R≥2.5;

[0164] (3) After the converter smelting is completed, LF furnace refining is carried out. The refining time is ≥30min, and argon gas is blown throughout the process.

[0165] (4) After refining, perform RH vacuum degassing with a vacuum degree ≤100pa and a vacuum holding time ≥15min.

[0166] (5) Then perform argon soft blowing, and the argon soft blowing time is ≥2min.

[0167] (6) Continuous casting of billets: The target stretching range for a cross-sectional size of 170mm×170mm is 2.0~2.2m / min, and the constant stretching speed is used for ≥95% of the time.

[0168] (7) The billet is fully re-ground, the steel billet is sent down, and the re-ground billet is inspected.

[0169] (8) In the high-strength wire rod heating step: the billet heating temperature is 1115℃, the cross-sectional temperature difference is 20℃, the furnace pressure is maintained at 30MPa, and the 170 square billet is in the furnace for 156 minutes, of which the time in the soaking section is 60 minutes.

[0170] (9) In the high wire rolling process: the high wire opening temperature is 1075℃; the finishing mill inlet temperature is 911℃; the sizing mill inlet temperature is 902℃; and the wire drawing temperature is 891℃.

[0171] (10) The Stellmore controlled cooling process is as follows: the wire rod undergoes slow cooling on the Stellmore air-cooling line. The inlet roller speed is 0.30 m / s, and the entire roller conveyor uses a fixed acceleration range of 1.01. The overlap point is not fixed to reduce the difference between the same rolls. The fans on the Stellmore roller conveyor are all in the off state, and no air cooling treatment is required to ensure that the microstructure fully completes the ferrite transformation. When the ambient temperature is 21℃, the two heat-insulating covers near the coiling opening are opened. The wire rod coiling temperature is 539℃.

[0172] (11) After the wire rod is air-cooled to room temperature, it is coiled, transported on the P / F line, cut at the beginning and end and sampled, bundled and packaged.

[0173] Table 1 shows the composition and corrosion resistance equivalent of the protective mesh structure components in Examples 1-4 and Comparative Example 1.

[0174]

[0175] In Table 1, the first category of representative steel wire materials are longitudinal wires and transverse wires with a bottom distance from the ground <34cm, and the second category of representative steel wire materials are transverse wires with a bottom distance from the ground ≥34cm; the carbon equivalent formula is: Ceq=C+Mn / 6+(Cr+Mo) / 5; the corrosion resistance equivalent weighted formula is (Ni+0.7Cr+0.5Mo).

[0176] Table 2 shows the parameters of the rolling steps in preparing the protective mesh structure in Examples 1-4 and Comparative Example 1.

[0177]

[0178] Table 3. Parameters of the slow cooling step in the preparation of the protective mesh structure in Examples 1-4 and Comparative Example 1.

[0179]

[0180] Table 4. Microstructure of the protective mesh structures prepared in Examples 1-4 and Comparative Example 1

[0181]

[0182]

[0183] Table 5 shows the performance of the protective mesh structures prepared in Examples 1-4 and Comparative Example 1.

[0184]

[0185] The weight loss rate in Table 5 is 1.0 × 10⁻⁶. -2 The results were obtained by 72-hour immersion corrosion tests in a mol / L NaHSO3 solution.

[0186] Figure 1This is a microstructure image of the longitudinal fibers and transverse fibers with a bottom near-ground distance of <34cm in Example 1, obtained using a wire rod. Figure 1 The microstructure shown is equiaxed ferrite with a grain size of 6.0 grade, a pearlite content of 2.3%, and no abnormal structures such as bainite and martensite.

[0187] Figure 2 This is a microstructure image of the wire rod with a bottom near-ground distance ≥34cm in Example 1. Figure 2 The microstructure shown is equiaxed ferrite with a grain size of 6.5, and no abnormal structures such as pearlite, bainite, or martensite.

[0188] The properties of the wire rod used in Example 1 for the longitudinal wire and the transverse wire with a bottom near-ground distance of <34cm are as follows: tensile strength Rm is 455MPa, Rm difference between the same coil is 12MPa, area shrinkage Z = 71%, elongation A = 43%, and weight loss ratio [W(this material) / W(Q235)] = 25.1%.

[0189] In Example 1, the properties of the wire rod with a bottom ground distance ≥34cm for the transverse wire are as follows: tensile strength Rm = 405MPa, Rm difference between coils = 11MPa, area shrinkage Z = 78%, elongation A = 53%, 1.0×10 -2 The weight loss ratio [W(this material) / W(Q235)] in a 72-hour immersion corrosion test in a mol / L NaHSO3 solution is 29.5%.

[0190] In Comparative Example 1, the carbon content of the first type of wire rod was 0.19%, exceeding the upper limit of the target. Under the same rolling process conditions, its pearlite and bainite contents did not meet the target requirements, and its tensile strength and weight loss ratio both exceeded the target range. The molybdenum content of the second type of wire rod was 0.45%, below the lower limit of the target. Under the same rolling process conditions, its tensile strength and microstructure were normal, but its weight loss ratio was below the target range. When the chemical composition of the material does not meet the preparation requirements, the thickness, density, and formation rate of the oxide layer on the material surface are insufficient, and its performance cannot meet the application requirements.

[0191] During use, corrosion typically occurs at the bottom of the material. The bottom material incorporates corrosion-resistant metallic elements, forming an oxide layer that provides protection during service. The upper layer, less susceptible to corrosion, utilizes a lower-cost composition. In the composite ultra-low carbon weather-resistant protective mesh structure prepared by this invention, the microstructure of the steel wire used for the longitudinal wires and the horizontal wires at the bottom (distance from the ground <34cm) is predominantly equiaxed ferrite, with a grain size range of 5.5–7.0, a pearlite proportion not exceeding 5.0%, and the absence of abnormal structures such as bainite and martensite. The mechanical properties of the steel wire are: tensile strength Rm 410–470MPa with a difference of ≤20MPa between coils, reduction of area Z ≥70%, and elongation A ≥42%. The corrosion resistance of the wire rod is: at 1.0×10⁻⁶... -2 A 72-hour immersion corrosion test was conducted in a mol / L NaHSO3 solution, and the weight loss ratio of the test steel [W(this material) / W(Q235)] was ≤28%.

[0192] The microstructure of the steel wire material used for horizontal wires with a bottom near-ground distance ≥34cm is mainly equiaxed ferrite, with a grain size ranging from 6.0 to 7.5, and no abnormal structures such as pearlite, bainite, or martensite. The mechanical properties of the wire rod are: tensile strength Rm ≤ 410MPa with Rm difference within the same coil ≤ 12MPa, reduction of area Z ≥ 75%, and elongation A ≥ 45%. The corrosion resistance of the wire rod is: at 1.0 × 10⁻⁶... -2 A 72-hour immersion corrosion test was conducted in a mol / L NaHSO3 solution, and the weight loss ratio of the test steel [W(this material) / W(Q235)] was ≤35%. The corrosion resistance of the material can be predicted by the weight loss ratio, and the service life can be calculated accordingly. The prediction shows that the service life of the integral protective mesh structure prepared by this invention exceeds 35 years.

[0193] This invention avoids over-performance and reduces production costs by classifying the usage area environment.

[0194] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0195] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A composite weathering resistant fence structure member of ultra-low carbon, characterized in that, It consists of the following structure: longitudinal wires and transverse wires with a bottom near-ground distance of <34cm, and transverse wires with a bottom near-ground distance of ≥34cm; The wire rod for longitudinal wires and horizontal wires with a bottom near-ground distance of <34cm is composed of the following components by mass percentage: C≤0.18%, Si≤0.05%, Mn≤0.08%, P≤0.012%, S≤0.008%, Cu0.25%~0.35%, Cr≥2.55%, Mo≥0.65%, Ni≥0.45%, with the remainder being Fe; carbon equivalent ≥0.88%, corrosion resistance equivalent ≥2.85%; the microstructure of the wire rod for longitudinal wires and horizontal wires with a bottom near-ground distance of <34cm is equiaxed ferrite, with a grain size range of 5.5-7.0, a pearlite proportion not exceeding 5.0%, and no abnormal structures, including but not limited to bainite and martensite; The wire rod for horizontal wire with a bottom near-ground distance ≥34cm is composed of the following components by mass percentage: C≤0.15%, Si≤0.05%, Mn≤0.05%, P≤0.012%, S≤0.008%, Cu0.20%~0.30%, Cr≥1.80%, Mo≥0.50%, Ni≥0.21%, with the remainder being Fe; carbon equivalent ≥0.61%, corrosion resistance equivalent ≥1.90%; the microstructure of the wire rod for horizontal wire with a bottom near-ground distance ≥34cm is equiaxed ferrite with a grain size range of 6.0-7.5, without any abnormal structures, including but not limited to pearlite, bainite, and martensite; The formula for calculating the carbon equivalent is: Carbon equivalent = C + Mn / 6 + (Cr+Mo+V) / 5 ; Wherein, C, Mn, Cr, and Mo represent the content of this element; The formula for calculating corrosion resistance equivalent is: Corrosion resistance equivalent = Ni + 0.7Cr + 0.5Mo; Among them, Cr, Mo, and Ni represent the content of this element.

2. The composite weather-resistant protective net structural member according to claim 1, wherein The wire rod for longitudinal wires and transverse wires with a bottom ground distance of <34cm is composed of the following components by mass percentage: C 0.16%, Si 0.048%, Mn 0.073%, P 0.01%, S 0.0065%, Cu 0.325%, Cr 2.82%, Mo 0.82%, Ni 0.55%, with the remainder being Fe; carbon equivalent = 0.90%, corrosion resistance equivalent = 2.934%; The wire rod for cross-wires with a bottom ground distance ≥34cm is composed of the following components by mass percentage: C 0.12%, Si 0.035%, Mn 0.039%, P 0.009%, S 0.0071%, Cu 0.278%, Cr 1.93%, Mo 0.62%, Ni 0.36%, with the remainder being Fe; carbon equivalent = 0.637%, corrosion resistance equivalent = 2.021%.

3. A method for preparing the composite ultra-low-carbon weather-resistant protective mesh structural member according to claim 1, comprising the following steps: The process involves blast furnace molten iron, desulfurization treatment, converter smelting, LF furnace refining, RH vacuum degassing, argon soft blowing, continuous casting of square billets, full grinding of square billets, billet delivery, acceptance of ground billets, high-speed wire rod heating, high-speed wire rod rolling, Stellmor controlled cooling, coiling, P / F line transportation, head and tail shearing and sampling, bundling, and packaging. The key feature is that in the high-speed wire rod heating step, the heating temperature is 1120±30℃, the cross-sectional temperature difference is ≤30℃, the furnace pressure is 25-40MPa, and the time a 170 square billet spends in the furnace is ≥140min, of which the time in the soaking zone is ≥50min.

4. The method of claim 3, wherein the method further comprises the step of: In the high-speed wire rod rolling process, the initial rolling temperature is 1060±30℃; the finishing mill inlet temperature is 900±20℃; the sizing mill inlet temperature is 900±10℃; and the wire drawing temperature is 890±10℃. ​ 5. The method of claim 4, wherein the method further comprises the step of: In the Stellmore controlled cooling process, the inlet roller speed is 0.30 m / s, and the roller conveyor uses a fixed acceleration range of 1.01 throughout the process. ​ 6. The method for preparing a composite ultra-low carbon weather-resistant protective mesh structure according to claim 5, characterized in that, In the Stellmore cooling process, when the ambient temperature is >35℃, open the 6 insulation covers near the winding port; when the ambient temperature is between 5 and 35℃, open the 2 insulation covers near the winding port; when the ambient temperature is <5℃, close all insulation covers.

7. The method for preparing a composite ultra-low carbon weather-resistant protective mesh structure according to claim 6, characterized in that, In the Stellmore controlled cooling process, the coil temperature is <550℃.

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