Method for producing small billets and wire rods, and method for weaving wire rods

Abstract

The application provides a billet and wire rod production method and a wire rod weaving processing method. The billet production method uses a large amount of scrap steel and a small amount of molten steel, smelts by using an electric furnace, reduces the initial carbon content, combines LF refining, uses fewer processes, accurately removes P, S, C and O elements in the molten steel, and can also make the Al content in the molten steel be within a target range, obtains clean molten steel, can continuously cast the billet, and uses an electric furnace+billet process flow to reduce carbon emission.

Description

Technical Field

[0001] This application relates to the field of wire rod production technology, and in particular to a method for producing small square billets and wire rods, and a method for weaving wire rods into wire mesh. Background Technology

[0002] Traditional converter long-process technology uses iron ore as the core raw material and requires multiple steps such as sintering, ironmaking, and converter steelmaking. It not only has high energy consumption, but also emits up to 2.0 tons of carbon dioxide per ton of steel. Its limitations are becoming increasingly prominent under the trend of low-carbon development.

[0003] Existing technologies typically employ a process flow of "converter → LF → RH treatment → large billet continuous casting → billet opening → billet grinding → small billet rolling → Stellmore controlled cooling" to produce low-carbon steel wire rod. This long-process converter process generates a large amount of carbon emissions and cannot meet green requirements. Summary of the Invention

[0004] The purpose of this application is to provide a method for producing small square billets for wire rod production. This method uses a large amount of scrap steel and smelts it in an electric furnace. By precisely controlling the P, C, O, and S content in the molten steel, small square billets are continuously cast. This method adopts an electric furnace small square billet process route and eliminates the RH process, thus solving the problem of high carbon emissions in the production of wire rod in the prior art.

[0005] To achieve one of the aforementioned objectives, one embodiment of this application provides a method for producing small square billets for wire rod production, comprising sequentially performed electric furnace smelting, LF refining, and continuous casting processes, wherein...

[0006] In the electric furnace smelting process, lime is added to the electric furnace in advance, using 50-80% scrap steel and 20-50% molten iron. After power is turned on, oxygen is blown in and the first batch of slag-forming agent is added. The slag basicity is controlled at 2.5-3.0 and the FeO content is 15-25%. When P≤0.01%, the slag is skimmed off, and the slag skimming rate is over 80%. Then, the second batch of slag-forming agent is added, and the slag basicity is controlled at 2.8-3.5. Oxygen is blown to decarburize. When the C content is 0.025%-0.040%, oxygen blowing is stopped. During the tapping process, a low-carbon ferromanganese alloy is added. The low-carbon ferromanganese alloy has a C content ≤0.05% and a Mn content ≥98%. Argon gas is blown for stirring throughout the tapping process. During the LF refining process, heating with electricity is prohibited when feeding aluminum wire. The amount of aluminum wire added is M. Al =0.001×{O}-0.036, M Al The unit is kg / t, and {O} represents the oxygen content in the molten steel, expressed in ppm. Then, calcium wire is fed in, controlling the O content in the molten steel to ≤0.004% and the Al content to ≤0.005%. Add slag-forming agent, control slag basicity ≥10, bottom-blown argon agitation, desulfurize to S content ≤0.01%; then add alloy for alloying, and perform soft stirring with argon. LF tapping temperature is 1600-1610℃, S content ≤0.01%, O content ≤0.004%, Al content ≤0.005%. In the continuous casting process, the outlet temperature of Zone 1 in the secondary cooling section is 1000-1020℃, the outlet temperature of Zone 2 is 1040-1060℃, the outlet temperature of Zone 3 is 1070-1090℃, the outlet temperature of Zone 4 is 990-1010℃, the straightening point temperature is 980-1000℃, the end temperature of continuous casting is 850-870℃, and the size of the continuously cast billet is (140-160)mm×(140-160)mm.

[0007] In one embodiment of this application, after adding a second batch of slagging agent, the oxygen flow rate of each oxygen lance on the furnace wall of the electric furnace is 2000-2500 Nm³. 3 / h, pressure is 1.0-1.3MPa, oxygen flow rate of oxygen lance at furnace door is 1800-2000Nm 3 / h, pressure is 0.8-1.2MPa.

[0008] In one embodiment of this application, in the electric furnace smelting process, 6-7 kg / t of lime is added to the electric furnace in advance, the first batch of slag-forming agent is 30-35 kg / t of lime, 1.2-2.0 kg / t of fluorite, and 10-12 kg / t of lightly calcined dolomite; the second batch of slag-forming agent is 20-30 kg / t of lime and 0.5-1.0 kg / t of fluorite.

[0009] In one embodiment of this application, in the LF refining process, after aluminum wire is fed in, low-silicon-calcium wire is fed in, and the feeding amount of low-silicon-calcium wire is 1.2-2.5 kg / t.

[0010] In one embodiment of this application, in the LF refining process, the type and amount of slag-forming agent are: lime 4-6 kg / t, fluorite 0.5-1.0 kg / t, calcium carbide 0.3-0.5 kg / t, and low-carbon steel slag surface deoxidizer 0.8-1 kg / t, so that the slag, by mass percentage, includes: CaO: 50-55%, Al2O3: 30-35%, SiO2≤5%, MgO: 5-8%, TFe+MnO≤1.0%.

[0011] In one embodiment of this application, during the LF refining process, at least one of ferrovanadium alloy, ferroniobium alloy, and ferrotitanium alloy is added according to the composition of the target wire rod, so that the sum of the vanadium content, niobium content, and titanium content in the molten steel is 0.02-0.05%; then, at least one of Ce and La rare earth cored wire is added to the molten steel at a wire feeding rate of 4.5-5.0 m / t, controlling the sum of Ce and La content in the molten steel to be 0.01-0.03%, and the ratio of the sum of Ce and La content to S content ≥ 2.5.

[0012] In one embodiment of this application, in the LF refining process, after the rare earth cored wire is fed in, bottom-blown argon gas is used for soft stirring, with an argon gas flow rate of 40-50 L / min and a stirring time of 8-10 min.

[0013] In one embodiment of this application, in the continuous casting process, a large ladle with a long nozzle and argon gas sealing protection are used for casting, and an alkaline covering agent and a mold protective slag are used; the water flow rate in the mold is 2000-2200 L / min, and the secondary cooling section adopts four-zone water mist cooling, with a total specific water flow rate of 0.85-1.05 L / kg.

[0014] In one embodiment of this application, during the continuous casting process, the casting speed is 2.4-2.6 m / min, and the solidification end with a solidification rate of 0.3-0.7 is lightly reduced, with a total reduction of 6-8 mm.

[0015] One embodiment of this application also provides a method for producing wire rod, wherein the wire rod is obtained by high-speed wire rolling and cooling processes from a small square billet produced by the aforementioned method. In the high-speed wire rod rolling process, the small square billet is heated before rolling at a temperature of 1050-1100℃, the initial rolling temperature is 970-1000℃, the compression ratios of roughing, intermediate rolling, pre-finishing rolling, and finishing rolling passes are 1.30-1.45, 1.25-1.35, 1.20-1.28, and 1.15-1.22, respectively, the finishing rolling inlet temperature is 880-900℃, the finishing rolling process temperature is controlled at 880-930℃, and the wire drawing temperature is 870-890℃. During the cooling process, when the wire rod temperature is >650℃, the cooling rate is 10-15℃ / s; when the wire rod temperature is 550℃≤650℃, the cooling rate is 1-3℃; when the wire rod temperature is <550℃, the cooling rate is 3-5℃ / s; and the temperature difference between the overlapping and non-overlapping points of the wire rod is ≤15℃.

[0016] In one embodiment of this application, the chemical composition of the wire rod, by mass percentage, includes: C: 0.025-0.040%, Si≤0.01%, Mn: 0.30-0.40%, S≤0.01%, P≤0.01%, Al≤0.005%, O≤0.004%, N≤0.005%, [Cr]+[Ni]+[Cu]≤0.15%, [Sn]+[As]+[Sb]≤0.01%, and at least one of V, Nb, and Ti is added, and [ V]+[Nb]+[Ti]=0.02-0.05%, with the addition of at least one rare earth element Ce or La, [Ce]+[La]=0.01-0.03%, ([Ce]+[La]) / [S]≥2.5, and the remainder being Fe and unavoidable impurities; wherein, [Cr], [Ni], [Cu], [Sn], [As], [Sb], [V], [Nb], [Ti], [Ce], [La], and [S] are the mass percentages of the corresponding elements in the wire rod.

[0017] In one embodiment of this application, the diameter of the wire rod is 5.5-6.5 mm; the tensile strength is 270-340 MPa; the reduction of area is ≥85%; the elongation is ≥45%; the size of transverse and longitudinal inclusions is ≤15 μm; the volume fraction of ferrite in the wire rod structure is 98-100%; and the ferrite grain size is 35-45 μm.

[0018] One embodiment of this application also provides a method for weaving wire rod, wherein the wire rod produced by the aforementioned wire rod production method is subjected to descaling → boronizing treatment → rough drawing → first intermediate heat treatment → intermediate drawing → second intermediate heat treatment → galvanizing and aluminum plating → fine drawing → weaving, wherein... In the rough drawing process, the wire rod is drawn 12-14 times to a diameter of 2.8-3.2mm. In the first heat treatment process, heat treatment is carried out in a protective atmosphere of mixed gas of N2 and H2, the heat treatment temperature is 680-700℃, the holding time is 2.5-3.0h, and then the furnace is cooled to 500℃ and then air-cooled. In the intermediate drawing process, the wire is drawn 8-10 times to continue drawing until the diameter is 1.6-1.8mm; In the second heat treatment process, heat treatment is carried out in a protective atmosphere of mixed gas of N2 and H2, with a heat treatment temperature of 660-680℃ and a holding time of 2.0-2.5h. After cooling in the furnace to 500℃, it is air-cooled. In the fine drawing process, the wire is drawn 15-18 times to continue drawing until the diameter is 0.3-0.7mm; During the netting process, the weaving speed is 20-45 rpm.

[0019] In one embodiment of this application, the descaling process employs a curved straightening roller in conjunction with a stainless steel wire brush for mechanical descaling. The contact pressure between the stainless steel wire brush and the wire rod surface is 0.3-0.5 MPa, and the roller rotation speed is 800-1200 rpm. After mechanical descaling, the surface roughness R of the wire rod is [not specified]. a ≤3.2μm, oxide scale removal rate 89-95%; then pickled with 12-16% hydrochloric acid for 4-6 min; In the boronizing process, a borax solution with a concentration of 8-12% and a temperature of 85-95℃ is used for immersion coating for 1-3 minutes, followed by hot air drying at 120-150℃ for 5-8 minutes.

[0020] In one embodiment of this application, in the zinc-aluminum plating process, the steel wire, after intermediate drawing and a second heat treatment, is pickled in 8-12% hydrochloric acid for 1-3 minutes, and then fluxed in a 30-40% ZnCl2·2NH4Cl mixed aqueous solution at a solution temperature of 60-80°C for 15-20 seconds. The fluxed steel wire is then dried in hot air at 120-150°C for 2-3 minutes. After fluxing, the steel wire is immersed in a hot-dip galvanizing melt at 430-450°C for 3-5 seconds, with the coating weight controlled at 100-150 g / m². 2 The hot-dip galvanized melt comprises, by mass percentage: Al: 5-7%, Ce / La: 0.03-0.05%, with the remainder being Zn.

[0021] In one embodiment of this application, the tensile strength of the steel wire is 650-900 MPa, and the flatness of the woven mesh is ≤0.5 mm / m. 2 The head breakage rate is ≤ 1 time / 100,000 meters.

[0022] One or more technical solutions provided in this application have at least the following technical effects or advantages: The method for producing small square billets for wire rod production provided in this application uses electric furnace smelting to reduce carbon emissions during the steelmaking process. Combined with LF refining for precise control of P, C, O, and S in molten steel, small square billets are obtained through continuous casting. The short process route of electric furnace-LF-small square billet continuous casting eliminates the need for RH refining to further reduce carbon emissions. The small square billets produced by the method provided in this application can be directly rolled into wire rod, solving the problem of high carbon emissions in the production of wire rod in the prior art. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0024] This application provides a method for producing small square billets for producing wire rod, including electric furnace smelting, LF refining, and continuous casting processes performed in sequence. Each process is described in detail below.

[0025] <Electric Furnace Smelting Process> Lime is added to the electric furnace beforehand, using 50-80% scrap steel and 20-50% molten iron. After powering on, oxygen is blown in, and the first batch of slag-forming agent is added. The slag basicity is controlled at 2.5-3.0, and the FeO content is 15-25%. When P≤0.01%, the slag is skimmed off, and the skimming rate is over 80%.

[0026] Then, the second batch of slag-forming agent is added, and the slag basicity is controlled at 2.8-3.5. Oxygen is blown for decarburization. When the C content is 0.025%-0.040%, oxygen blowing is stopped. During the tapping process, a low-carbon ferromanganese alloy is added. The low-carbon ferromanganese alloy has a C content ≤0.05% and a Mn content ≥98%, and argon gas is blown for stirring throughout the tapping process.

[0027] The scrap steel is preferably clean or high-quality scrap steel, such as scrap steel with Cr content <0.10%, Ni content <0.10%, Cu content <0.05%, Mo content <0.01%, Ti content <0.10%, Nb content <0.005%, V content <0.05%, and S content ≤0.010%. The molten iron is preferably pre-treated molten iron with an S content ≤0.002%. A larger quantity of scrap steel and a smaller quantity of molten iron are used; the scrap steel is melted by lowering the electrodes and applying electricity.

[0028] Adding lime in advance can accelerate slag formation, shorten the electric arc furnace smelting cycle, enhance the dephosphorization effect during the initial dephosphorization stage, and reduce the risk of phosphorus reversion. Oxygen is blown in and lime is added to form slag. The molten steel temperature is 1560-1580°C. The basicity and oxidizing properties of the slag are controlled to dephosphorize the molten steel. When P ≤ 0.01%, the slag is skimmed off to prevent phosphorus reversion. After skimming, slag is added again, and the slag basicity is adjusted to 2.8-3.5. The molten steel temperature is raised to 1650-1680°C, and then oxygen is blown in for decarburization.

[0029] The tapping temperature of the electric furnace is controlled at 1685-1695℃. When the steel is tapped to 1 / 3 of its capacity, a low-carbon ferromanganese alloy is added at a rate of 3.2-4.2 kg / t. Slag discharge during tapping is strictly prohibited. The argon flow rate during tapping is 100-150 L / min to prevent the molten steel from being exposed.

[0030] In some embodiments, after adding the second batch of slag-making agent to make slag, the oxygen flow rate of each wall oxygen lance of the electric furnace is 2000 - 2500 Nm 3 / h, the pressure is 1.0 - 1.3 MPa, the oxygen flow rate of the door oxygen lance is 1800 - 2000 Nm 3 / h, the pressure is 0.8 - 1.2 MPa. Decarburization is carried out by strong oxygen blowing.

[0031] In some embodiments, in the electric furnace smelting process, 6 - 7 kg / t of lime is pre-added to the electric furnace. The first batch of slag-making agent is 30 - 35 kg / t of lime, 1.2 - 2.0 kg / t of fluorite, and 10 - 12 kg / t of lightly burned dolomite; the second batch of slag-making agent is 20 - 30 kg / t of lime and 0.5 - 1.0 kg / t of fluorite.

[0032] <LF Refining Process> Prohibit electric heating, feed in aluminum wire, and the addition amount M of aluminum wire Al = 0.001×{O} - 0.036, M Al The unit is kg / t, {O} is the oxygen content in molten steel, and the unit is ppm; then feed in calcium wire to control the O content in molten steel ≤ 0.004% and the Al content ≤ 0.005%; Add slag-making agent to control the slag basicity ≥ 10, stir with bottom blowing argon, and desulfurize until the S content ≤ 0.01%; then add alloy for alloying, and carry out soft stirring with argon. The tapping temperature of LF is 1600 - 1610 °C, the S content ≤ 0.01%, the O content ≤ 0.004%, and the Al content ≤ 0.005%.

[0033] Since decarburization has been completed in the electric furnace smelting process, electric heating is prohibited throughout the LF refining process to avoid the generation of electric arcs on the graphite electrodes to heat the molten steel and cause electrode burnout at high temperatures, and to increase carbon in the molten steel.

[0034] After the ladle reaches the LF refining station, start bottom blowing argon with an argon flow rate of 200 - 450 L / min and stir for 2 - 3 min.

[0035] Feeding in aluminum wire and low-silicon calcium wire is the core operation to jointly complete deep deoxidation, precisely control the morphology of inclusions, and ensure the purity of molten steel. The core role of feeding in aluminum wire is to pre-deoxidize the molten steel deeply, quickly reduce the oxygen content, lay the foundation for the treatment of calcium wire, and avoid the ineffective consumption of calcium. The core component of low-silicon calcium wire is metallic calcium (or calcium-based alloy), and the silicon content is extremely low to avoid increasing silicon in low-carbon steel. Its role is secondary deep deoxidation, reducing the oxygen content to ≤ 0.004%, modifying Al2O3 inclusions, and at the same time promoting the floating of inclusions to eliminate the harm of hard and brittle inclusions.

[0036] In some embodiments, after feeding aluminum wire, low-silicon calcium wire (Si≤0.01%) is fed in at a rate of 1.2-2.5 kg / t. After deoxidation, a slag-forming agent is added again to create white slag for desulfurization. After desulfurization is completed, alloying is carried out.

[0037] In some embodiments, the types and amounts of slag-forming agents are as follows: lime 4-6 kg / t, fluorite 0.5-1.0 kg / t, calcium carbide 0.3-0.5 kg / t, and low-carbon steel slag surface deoxidizer 0.8-1 kg / t, so that the slag, by mass percentage, includes: CaO: 50-55%, Al2O3: 30-35%, SiO2≤5%, MgO: 5-8%, TFe+MnO≤1.0%.

[0038] The low-carbon steel slag surface deoxidizer includes, by mass percentage: elemental Al ≥ 25%, Al2O3: 12%~20%, CaO: 16%~24%, CaF2: 17%~23%, SiO2 ≤ 8%, H2O ≤ 1%, and its particle size is 15~35mm.

[0039] In some embodiments, during alloying, at least one of ferrovanadium alloy, ferroniobium alloy, and ferrotitanium alloy is added according to the composition of the target wire rod, so that the sum of the vanadium content, niobium content, and titanium content in the molten steel is 0.02-0.05%; then, at least one of Ce and La rare earth cored wire is added to the molten steel at a wire feeding rate of 4.5-5.0 m / t, controlling the sum of the Ce and La content in the molten steel to be 0.01-0.03%, and the ratio of the sum of the Ce and La content to the S content ≥ 2.5.

[0040] Among them, ferrovanadium, ferroniobium, and ferrotitanium alloys all use low-carbon alloys to avoid carbon addition to the molten steel. By mass percentage, in the low-carbon ferrovanadium alloy, C ≤ 0.1%, V: 48-55%, with the remainder being iron and unavoidable impurities; in the low-carbon ferroniobium alloy, C ≤ 0.05%, Nb ≥ 62%, with the remainder being iron and unavoidable impurities; in the low-carbon ferrotitanium alloy, C ≤ 0.05%, Ti: 30-35%, with the remainder being iron and unavoidable impurities.

[0041] Adding Ce and / or La rare earth cored wire in the later stage of LF refining allows the rare earth elements to control the morphology of inclusions in the molten steel. This transforms MnS and Al2O3 that have not fully floated to the surface into spherical, fine, and uniformly distributed rare earth oxides and sulfides, reducing stress concentration points and crack initiation points in the small billet. As a result, the small billet is less prone to cracking or breaking during subsequent processing.

[0042] In some implementations, during the LF refining process, after the rare earth cored wire is fed in, bottom-blown argon gas is used for soft stirring, with an argon gas flow rate of 40-50 L / min and a stirring time of 8-10 min.

[0043] After adding rare earth cored wire, the mixture is stirred by bottom blowing argon gas. This promotes the melting and rapid dispersion of the rare earth cored wire in the molten steel, and also promotes the modification of inclusions in the molten steel.

[0044] Carbon-free steel ladles are used in the electric arc furnace smelting and LF refining processes to avoid carbon reversion.

[0045] <Continuous casting process> The outlet temperature of the second cooling section is 1000-1020℃ for zone 1, 1040-1060℃ for zone 2, 1070-1090℃ for zone 3, 990-1010℃ for zone 4, 980-1000℃ for the straightening point, 850-870℃ for the end of continuous casting, and the size of the continuously cast billet is (140-160)mm×(140-160)mm.

[0046] The second cooling section uses weak cooling and strictly controls the temperature of each section to avoid cracking, improve the surface quality of the billet, and eliminate the need for grinding.

[0047] In some implementations, the continuous casting process uses a ladle with a long nozzle and argon gas sealing for protection during casting, and employs an alkaline covering agent and a mold protective slag; the mold water flow rate is 2000-2200 L / min, and the secondary cooling section uses four-zone water mist cooling with a total specific water flow rate of 0.85-1.05 L / kg.

[0048] The mold flux, by mass percentage, comprises: SiO2: 37±3%, CaO: 30±5%, Al2O3: 7±2.5%, Na2O: 5.6±2.5%, MgO: 4±2%, F - The content of the protective slag is 7±3%, the basicity of the crystallizer protective slag is 0.81±0.06, and the viscosity of the crystallizer protective slag is 0.46±0.12 Pa·s. The numbers after the "±" sign represent the fluctuation range within the corresponding content / basicity / viscosity range.

[0049] The continuous casting process employs a long nozzle in the ladle, argon sealing, alkaline covering agent, and mold flux, forming a seamless protection from the ladle to the mold, effectively isolating air. The alkaline covering agent and mold flux absorb floating rare earth inclusions, preventing them from being drawn into the billet shell or deteriorating the performance of the flux, thus ensuring the cleanliness of the molten steel from the source.

[0050] In some implementations, during the continuous casting process, a light reduction is performed at the solidification end with a casting speed of 2.4-2.6 m / min and a solids content of 0.3-0.7, resulting in a total reduction of 6-8 mm. In the reduction zone, the core of the small billet remains a pasty area with a high surface temperature, allowing for efficient light reduction without generating internal cracks. Light reduction at the solidification end avoids shrinkage cavities and reduces center segregation.

[0051] In this application, a large amount of scrap steel and a small amount of molten iron are used for electric furnace smelting, which reduces carbon emissions from the source. The electric furnace smelting is combined with LF refining. The electric furnace smelting involves oxygen blowing and slag formation for dephosphorization. After slag removal, slag formation and oxygen blowing continue for decarburization. The LF refining strictly controls the amount of aluminum and calcium wire added for deoxidation and modification of inclusions. Then, slag formation is used for diffusion desulfurization and provides an excellent O content environment for alloying, which improves the alloy yield. Finally, rare earth cored wire is added to modify the inclusions.

[0052] This application obtains clean molten steel with the target alloy content through electric furnace smelting and LF refining. This steel is less prone to nodule formation during continuous casting, enabling the continuous casting of small billets. Subsequent processing eliminates the need for billet preparation, further avoiding excess carbon emissions. Furthermore, the continuous casting process protects the casting process and strictly controls the interruption temperature, ensuring the surface quality of the small billets and providing excellent conditions for subsequent processing.

[0053] In some embodiments, the chemical composition of the small square billet, by mass percentage, includes: C: 0.025-0.040%, Si≤0.01%, Mn: 0.30-0.40%, S≤0.01%, P≤0.01%, Al≤0.005%, O≤0.004%, N≤0.005%, [Cr]+[Ni]+[Cu]≤0.15%, [Sn]+[As]+[Sb]≤0.01%, with at least one of V, Nb, and Ti added, and [V]+ [Nb]+[Ti]=0.02-0.05%, with the addition of at least one rare earth element Ce or La, [Ce]+[La]=0.01-0.03%, ([Ce]+[La]) / [S]≥2.5, and the remainder being Fe and unavoidable impurities; wherein, [Cr], [Ni], [Cu], [Sn], [As], [Sb], [V], [Nb], [Ti], [Ce], [La], and [S] are the mass percentages of each element in the small billet.

[0054] The main functions of each chemical component in this application are analyzed and explained in detail below: Carbon (C) is the most important element in steel, and its content directly determines the material's strength and ductility. As the C content increases, the steel's strength and hardness rise, while its ductility and toughness decrease. Wire rods used for wire mesh weaving experience significant deformation during subsequent processing, requiring a certain level of strength as well as good ductility and toughness. Therefore, in this application, the C content is controlled between 0.025% and 0.040%.

[0055] Si plays a role in solid solution strengthening, increasing the strength of steel, but it also leads to a decrease in plasticity and toughness. Furthermore, silicon easily forms silicate nonmetallic inclusions in steel. These inclusions are stress concentration points during cold drawing, easily causing wire breakage and reducing drawing performance. Therefore, the Si content in this application should be controlled at Si ≤ 0.01%.

[0056] Mn plays a role in solid solution strengthening, improving the strength of wire rod. Mn is also a good deoxidizer; it can combine with sulfur to form manganese sulfide, eliminating the harmful effects of sulfur in steel and reducing hot brittleness. However, excessive Mn content can reduce the plasticity and processing performance of wire rod. Therefore, this application controls the Mn content at 0.30-0.40%.

[0057] S, P, Al, O, and N are considered harmful elements in the wire rods of this application. S easily forms MnS inclusions, leading to hot brittleness and reduced plasticity in steel. P tends to segregate at grain boundaries, causing cold brittleness and reducing low-temperature toughness. Al easily forms high-hardness, non-deformable Al2O3 inclusions, which are fatal to drawing performance, causing wire breakage during drawing. O and N form oxide and nitride inclusions, significantly reducing the plasticity and toughness of steel; nitrogen also causes age-induced embrittlement. Therefore, these harmful elements should be minimized as much as possible. This application aims to control the wire rod content to S≤0.01%, P≤0.01%, Al≤0.005%, O≤0.004%, and N≤0.005%.

[0058] Cr, Ni, and Cu are mostly residual elements introduced from scrap steel raw materials. These elements can increase hardenability, affect weldability and microstructure uniformity. Cu is prone to surface brittleness during hot working. In order to avoid the adverse effects of residual elements on the plasticity and machinability of low carbon steel, the sum of Cr, Ni, and Cu content in this application is controlled within the range of ≤0.15%.

[0059] Sn, As, and Sb are typical harmful residual elements that tend to segregate at grain boundaries, leading to grain boundary embrittlement, hot brittleness, and hot rolling cracking, significantly reducing the hot workability and toughness of steel. Therefore, the sum of Sn, As, and Sb content in this application is controlled to be ≤0.01%.

[0060] Microalloying elements Nb, V, and Ti are strong carbonitride forming elements. They enhance strength through precipitation strengthening and grain refinement. During controlled rolling and cooling or subsequent drawing / annealing, they precipitate fine carbonitride particles (such as TiN and NbC), strongly hindering dislocation movement and producing a significant precipitation strengthening effect. These dispersed particles effectively inhibit the growth of austenite grains during heating and rolling, resulting in fine ferrite grains after cooling, producing a grain refinement strengthening effect that significantly improves strength and toughness. If the addition amount is too small, the expected strengthening effect will not be achieved. At the same time, excessive microalloying elements should be avoided to prevent the formation of coarse carbonitrides, which would reduce plasticity. Therefore, this application adds at least one V, Nb, or Ti element to the wire rod, and the sum of the V, Nb, and Ti contents is controlled within the range of 0.02-0.05%. Rare earth elements Ce and La are stronger deoxidizers and desulfurizers than aluminum and calcium, further purifying molten steel. Their core functions are desulfurization, deoxidation, and improvement of inclusion morphology. Rare earth elements react with S and O in steel to generate spherical, high-melting-point, low-hardness rare earth composite inclusions with a coefficient of thermal expansion similar to the matrix, reducing elongated and angular harmful inclusions (such as MnS and Al2O3), reducing stress concentration, and improving the plasticity and fatigue properties of steel. However, excessive rare earth elements can form large-sized rare earth inclusions, which can deteriorate processing performance. Therefore, this application adds at least one rare earth element, Ce or La, to wire rod, with the sum of Ce and La contents controlled at 0.01-0.03%.

[0061] The controlled ratio of the sum of Ce and La content to S content ensures sufficient and excessive rare earth atoms to completely fix all sulfur atoms, achieving 100% modification of sulfides. If the ratio is too low, the modification is incomplete, and streaky MnS will still exist; if it is too high, coarse rare earth oxides may form, becoming a new source of hazard. Therefore, this application controls the ratio of the sum of Ce and La content to S content to ≥2.5.

[0062] The low-carbon and low-silicon composition significantly purifies the steel matrix, reduces plasticity loss caused by solid solution strengthening, and eliminates grain boundary embrittlement, laying the foundation for extremely high elongation and reduction of area. Microalloying improves the material's strength and toughness, achieving an effective increase in strength while maintaining low carbon and low silicon content, meeting the requirement of "both strong and tough" for wire mesh. The addition of rare earth elements controls the morphology of inclusions, transforming highly harmful long strips of MnS and angular Al2O3 into spherical, fine, and uniformly distributed rare earth oxides and sulfides. These are less prone to cracking during deformation and less likely to become stress concentration points, eliminating the main crack origin and allowing the wire mesh to withstand greater local deformation and repeated bending, greatly improving the success rate of the weaving process and the durability of the finished mesh.

[0063] This application also provides a method for producing wire rod, wherein the wire rod is obtained by high-speed wire rolling and cooling processes from small square billets produced by the aforementioned method. In the high-speed wire rod rolling process, the small square billet is heated before rolling at a temperature of 1050-1100℃, the initial rolling temperature is 970-1000℃, the compression ratios of roughing, intermediate rolling, pre-finishing rolling, and finishing rolling passes are 1.30-1.45, 1.25-1.35, 1.20-1.28, and 1.15-1.22, respectively, the finishing rolling inlet temperature is 880-900℃, the finishing rolling process temperature is controlled at 880-930℃, and the wire drawing temperature is 870-890℃. During the cooling process, when the wire rod temperature is >650℃, the cooling rate is 10-15℃ / s; when the wire rod temperature is 550℃≤650℃, the cooling rate is 1-3℃; when the wire rod temperature is <550℃, the cooling rate is 3-5℃ / s; and the temperature difference between the overlapping and non-overlapping points of the wire rod is ≤15℃.

[0064] By synergistically controlling the temperature, compression ratio, and cooling rate, the system achieves refined grains, uniform microstructure, high plasticity, and low defects. Appropriate heating temperatures ensure sufficient austenite homogenization, preventing undissolved ferrite residue and ensuring complete dissolution of microalloying elements into the austenite, laying the foundation for subsequent cooling and precipitation of fine, dispersed strengthening phases. Strict control of the compression ratio at each rolling stage improves the surface quality of the wire rod. Low finishing rolling temperatures are used to avoid mixed grains. Appropriate wire drawing temperatures and segmented cooling achieve the desired microstructure. Rapid cooling in the early stage suppresses grain coarsening, slow cooling in the middle stage forms uniform, fine polygonal ferrite, and slow cooling in the later stage reduces thermal stress caused by internal and external temperature differences, improving the dimensional stability of the wire rod.

[0065] Preferably, the high-speed wire rod rolling process has a total of 28 rolling passes, including 6 roughing passes, 6 final rolling passes, 4 pre-finishing passes, 10 finishing passes, and 2 sizing passes after finishing.

[0066] Since the wire rod is obtained by high-speed wire rolling and cooling of the aforementioned small square billets, its chemical composition is the same as that of the aforementioned small square billets. That is, the chemical composition of the wire rod, by mass percentage, includes: C: 0.025-0.040%, Si≤0.01%, Mn: 0.30-0.40%, S≤0.01%, P≤0.01%, Al≤0.005%, O≤0.004%, N≤0.005%, [Cr]+[Ni]+[Cu]≤0.15%, [Sn]+[As]+[Sb]≤0.01%, and at least one of V, Nb, and Ti is added, with [V]+[Nb]... +[Ti]=0.02-0.05%, with the addition of at least one rare earth element Ce or La, [Ce]+[La]=0.01-0.03%, ([Ce]+[La]) / [S]≥2.5, and the remainder being Fe and unavoidable impurities; wherein, [Cr], [Ni], [Cu], [Sn], [As], [Sb], [V], [Nb], [Ti], [Ce], [La], and [S] are the mass percentages of the corresponding elements in the wire rod.

[0067] In some embodiments, the diameter of the wire rod obtained by rolling the small square billet by high-speed wire rod rolling is 5.5-6.5 mm; through the coordinated control of "temperature-compression ratio-cooling rate", the tensile strength of the wire rod is 270-340 MPa, the reduction of area is ≥85%, the elongation is ≥45%, the size of transverse and longitudinal inclusions is ≤15 μm, the volume ratio of ferrite in the wire rod microstructure is 98-100%, and the ferrite grain size is 35-45 μm.

[0068] This application also provides a method for weaving wire rod into a mesh, wherein the wire rod produced by the aforementioned wire rod production method undergoes descaling → boronizing treatment → rough drawing → first intermediate heat treatment → intermediate drawing → second intermediate heat treatment → galvanizing and aluminum plating → fine drawing → mesh weaving. In the rough drawing process, the wire rod is drawn 12-14 times to a diameter of 2.8-3.2mm. In the first heat treatment process, heat treatment is carried out in a protective atmosphere of mixed gas of N2 and H2, the heat treatment temperature is 680-700℃, the holding time is 2.5-3.0h, and then the furnace is cooled to 500℃ and then air-cooled. In the intermediate drawing process, the wire is drawn 8-10 times to continue drawing until the diameter is 1.6-1.8mm; In the second heat treatment process, heat treatment is carried out in a protective atmosphere of mixed gas of N2 and H2, with a heat treatment temperature of 660-680℃ and a holding time of 2.0-2.5h. After cooling in the furnace to 500℃, it is air-cooled. In the fine drawing process, the wire is drawn 15-18 times to continue drawing until the diameter is 0.3-0.7mm; During the netting process, the weaving speed is 20-45 rpm.

[0069] The wire rod undergoes three stages of drawing: roughing, intermediate drawing, and fine drawing. After the roughing and intermediate drawing stages, it is heat-treated before further drawing to eliminate work hardening caused by the previous drawing stages and restore the material's plasticity and toughness, thus enabling subsequent drawing with larger deformation. The preferred volume ratio of the N2 and H2 mixture is 95:5.

[0070] In some implementations, the descaling process employs a curved straightening roller in conjunction with a stainless steel wire brush for mechanical descaling. The contact pressure between the stainless steel wire brush and the wire rod surface is 0.3-0.5 MPa, and the roller rotation speed is 800-1200 rpm. After mechanical descaling, the surface roughness Ra of the wire rod is ≤3.2 μm, and the oxide scale removal rate is 89-95%. This is followed by pickling with 12-16% hydrochloric acid for 4-6 minutes. This combined "mechanical descaling + pickling" process efficiently, economically, and environmentally friendly removes oxide scale from the wire rod surface, resulting in a clean surface and laying a low-friction, scratch-resistant foundation for subsequent large-deformation drawing.

[0071] After mechanical descaling and pickling, the surface is rinsed with high-pressure water to remove particulate impurities after mechanical descaling and hydrochloric acid solution after pickling. The pressure of the high-pressure water is 3-5 MPa.

[0072] In the boronizing process, a borax solution with a concentration of 8-12% and a temperature of 85-95℃ is used for immersion coating for 1-3 minutes, followed by hot air drying at 120-150℃ for 5-8 minutes.

[0073] In some embodiments, during the zinc-aluminum plating process, the steel wire, after intermediate drawing and a second heat treatment, is pickled in 8-12% hydrochloric acid for 1-3 minutes, then fluxed in a 30-40% ZnCl2·2NH4Cl mixed aqueous solution at a solution temperature of 60-80°C for 15-20 seconds. The fluxed steel wire is then dried in hot air at 120-150°C for 2-3 minutes. After fluxing, the steel wire is immersed in a hot-dip galvanizing melt at 430-450°C for 3-5 seconds, with the coating weight controlled at 100-150 g / m². 2 The hot-dip galvanized melt comprises, by mass percentage: Al: 5-7%, Ce / La: 0.03-0.05%, with the remainder being Zn.

[0074] In the galvanizing process, although the hydrochloric acid pickling effectively removes the oxide scale and rust from the surface of the steel wire, the fresh metal surface after pickling is in a highly activated state. When it comes into contact with air or water, a very thin oxide film will form in a very short time (even within a few seconds).

[0075] The acidic ZnCl2·2NH4Cl mixed aqueous solution dissolves the extremely thin layer of oxides or ferric hydroxide (iron salt) formed after pickling, ensuring that the steel wire surface is an absolutely clean, activated, pure iron substrate before galvanizing. When the steel wire is removed from the ZnCl2·2NH4Cl mixed aqueous solution, a layer of liquid flux salt film adheres to its surface. It is then dried with hot air at 120-150℃ to evaporate the moisture. After drying, a dry, dense solid salt film (mainly composed of ZnCl2·NH4Cl composite salt) remains on the surface of the steel wire. This salt film effectively isolates the air, preventing the clean steel wire surface from being re-oxidized during transport before entering the zinc pot.

[0076] When a steel wire coated with a flux salt film is immersed in molten Zn-Al alloy at 430-450°C, the salt film melts, decomposes, and volatilizes rapidly, and then the plating process begins.

[0077] In some embodiments, the tensile strength of the steel wire is 650-900 MPa, and the flatness of the woven mesh is ≤0.5 mm / m. 2 The head breakage rate is ≤ 1 time / 100,000 meters.

[0078] This application redesigns the composition of hot-rolled wire rod, adding V, Nb, and Ti for microalloying to improve its strength and toughness. The addition of rare earth elements La and Ce modifies inclusions while reducing the impact of residual elements in high-scrap-ratio steel. A process flow of "electric furnace smelting → LF refining → small billet continuous casting → high-speed wire rod rolling → Steyrmo controlled cooling" is adopted to achieve low-energy consumption and low-carbon emission green smelting. By controlling the parameters of the smelting and rolling processes, precise control over inclusions, microstructure, and mechanical properties is achieved, further improving the overall performance of the wire rod. This meets the demands of high-end wire mesh fabrication for large deformation and high-speed processing, producing high-quality, high-performance, and high-precision high-end wire mesh fabric with significant economic and environmental benefits.

[0079] The technical solution of this application will be further described below with reference to some specific embodiments.

[0080] Table 1 Chemical composition of wire rod (%)

[0081] Note: In the table, Cr+Ni+Cu is the sum of Cr, Ni, and Cu contents, which is the [Cr]+[Ni]+[Cu] value mentioned earlier; Sn+As+Sb is the sum of Sn, As, and Sb contents, which is the [Sn]+[As]+[Sb] value mentioned earlier; V+Nb+Ti is the sum of V, Nb, and Ti contents, which is the [V]+[Nb]+[Ti] value mentioned earlier; Ce+La is the sum of Ce and La contents, which is the [Ce]+[La] value mentioned earlier; (Ce+La) / S is the ratio of the sum of Ce and La contents to the S content, which is the ([Ce]+[La]) / [S] value mentioned earlier. This value is not included.

[0082] Table 2 Dephosphorization in Electric Furnace Smelting

[0083] Table 3 Decarburization in Electric Furnace Smelting

[0084] Table 4 Steelmaking by Electric Furnace

[0085] Table 5 LF Refining Deoxidation

[0086] Table 6 LF Refining Desulfurization

[0087] Table 7 Continuous Casting Process

[0088] Table 8 High-speed wire rod rolling process

[0089] Table 9. Compression Ratio of Passes in High-Speed ​​Wire Rolling

[0090] Table 10 Cooling Process

[0091] Table 11 Wire Rod Structure and Properties

[0092] Table 12 Descaling of Wire Rods

[0093] Table 13 Boring Treatment of Wire Rods

[0094] Table 14 Pulling and Weaving

[0095] Table 15 Zinc-plated aluminum

[0096] Table 16 Properties of Steel Wire and Mesh

[0097] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0098] The detailed descriptions listed above are merely specific descriptions of feasible implementation methods of this application and are not intended to limit the scope of protection of this application. All equivalent implementation methods or modifications made without departing from the spirit of the art of this application should be included within the scope of protection of this application.

Claims

1. A method for producing small square billets for producing wire rod, characterized in that, This includes the sequential processes of electric furnace smelting, LF refining, and continuous casting, among which... In the electric furnace smelting process, lime is added to the electric furnace in advance, using 50-80% scrap steel and 20-50% molten iron. After power is turned on, oxygen is blown in and the first batch of slag-forming agent is added. The slag basicity is controlled at 2.5-3.0 and the FeO content is 15-25%. When P≤0.01%, the slag is skimmed off, and the slag skimming rate is over 80%. Then, the second batch of slag-forming agent is added, and the slag basicity is controlled at 2.8-3.

5. Oxygen is blown to decarburize. When the C content is 0.025%-0.040%, oxygen blowing is stopped. During the tapping process, a low-carbon ferromanganese alloy is added. The low-carbon ferromanganese alloy has a C content ≤0.05% and a Mn content ≥98%. Argon gas is blown for stirring throughout the tapping process. During the LF refining process, heating with electricity is prohibited when feeding aluminum wire. The amount of aluminum wire added is M. Al =0.001×{O}-0.036, M Al The unit is kg / t, and {O} represents the oxygen content in the molten steel, expressed in ppm. Then, calcium wire is fed in, controlling the O content in the molten steel to ≤0.004% and the Al content to ≤0.005%. Add slag-forming agent, control slag basicity ≥10, bottom-blown argon agitation, desulfurize to S content ≤0.01%; then add alloy for alloying, and perform soft stirring with argon. LF tapping temperature is 1600-1610℃, S content ≤0.01%, O content ≤0.004%, Al content ≤0.005%. In the continuous casting process, the outlet temperature of Zone 1 in the secondary cooling section is 1000-1020℃, the outlet temperature of Zone 2 is 1040-1060℃, the outlet temperature of Zone 3 is 1070-1090℃, the outlet temperature of Zone 4 is 990-1010℃, the straightening point temperature is 980-1000℃, the end temperature of continuous casting is 850-870℃, and the size of the continuously cast billet is (140-160)mm×(140-160)mm.

2. The method for producing small square billets for producing wire rod according to claim 1, characterized in that, After adding the second batch of slagging agent, the oxygen flow rate of each oxygen lance on the furnace wall of the electric furnace is 2000-2500 Nm. 3 / h, pressure is 1.0-1.3MPa, oxygen flow rate of oxygen lance at furnace door is 1800-2000Nm 3 / h, pressure is 0.8-1.2MPa.

3. The method for producing small square billets for producing wire rod according to claim 2, characterized in that, In the electric furnace smelting process, 6-7 kg / t of lime is added to the electric furnace in advance. The first batch of slag-forming agents consists of 30-35 kg / t of lime, 1.2-2.0 kg / t of fluorite, and 10-12 kg / t of lightly calcined dolomite. The second batch of slag-forming agents consists of 20-30 kg / t of lime and 0.5-1.0 kg / t of fluorite.

4. The method for producing small square billets for producing wire rod according to claim 1, characterized in that, In the LF refining process, after aluminum wire is fed in, low-silicon-calcium wire is fed in at a rate of 1.2-2.5 kg / t.

5. The method for producing small square billets for producing wire rod according to claim 4, characterized in that, In the LF refining process, the types and amounts of slag-forming agents are: lime 4-6 kg / t, fluorite 0.5-1.0 kg / t, calcium carbide 0.3-0.5 kg / t, and low-carbon steel slag surface deoxidizer 0.8-1 kg / t, so that the slag, by mass percentage, includes: CaO: 50-55%, Al2O3: 30-35%, SiO2≤5%, MgO: 5-8%, TFe+MnO≤1.0%.

6. The method for producing small square billets for producing wire rod according to claim 1, characterized in that, In the LF refining process, during alloying, at least one of ferrovanadium alloy, ferroniobium alloy, and ferrotitanium alloy is added according to the composition of the target wire rod, so that the sum of vanadium content, niobium content, and titanium content in the molten steel is 0.02-0.05%; then, at least one of Ce and La rare earth cored wire is added to the molten steel at a wire feeding rate of 4.5-5.0 m / t, controlling the sum of Ce and La content in the molten steel to be 0.01-0.03%, and the ratio of the sum of Ce and La content to S content ≥2.

5.

7. The method for producing small square billets for producing wire rod according to claim 6, characterized in that, In the LF refining process, after the rare earth cored wire is fed in, bottom-blown argon gas is used for soft stirring. The argon gas flow rate is 40-50 L / min, and the stirring time is 8-10 min.

8. The method for producing small square billets for producing wire rod according to claim 1, characterized in that, In the continuous casting process, a large ladle with a long nozzle and argon gas sealing protection are used for casting, along with an alkaline covering agent and a mold protective slag. The water flow rate in the mold is 2000-2200 L / min, and the secondary cooling section uses four-zone water mist cooling with a total specific water flow rate of 0.85-1.05 L / kg.

9. The method for producing small square billets for producing wire rod according to claim 1, characterized in that, In the continuous casting process, the casting speed is 2.4-2.6 m / min, and the solidification end with a solidification rate of 0.3-0.7 is lightly reduced, with a total reduction of 6-8 mm.

10. A method for producing wire rod, characterized in that, The wire rod is obtained by high-speed wire rolling and cooling processes using a small square billet produced by the production method described in any one of claims 1 to 9. In the high-speed wire rod rolling process, the small square billet is heated before rolling at a temperature of 1050-1100℃, the initial rolling temperature is 970-1000℃, the compression ratios of roughing, intermediate rolling, pre-finishing rolling, and finishing rolling passes are 1.30-1.45, 1.25-1.35, 1.20-1.28, and 1.15-1.22, respectively, the finishing rolling inlet temperature is 880-900℃, the finishing rolling process temperature is controlled at 880-930℃, and the wire drawing temperature is 870-890℃. During the cooling process, when the wire rod temperature is >650℃, the cooling rate is 10-15℃ / s; when the wire rod temperature is 550℃≤650℃, the cooling rate is 1-3℃; when the wire rod temperature is <550℃, the cooling rate is 3-5℃ / s; and the temperature difference between the overlapping and non-overlapping points of the wire rod is ≤15℃.

11. The method for producing wire rod according to claim 10, characterized in that, The chemical composition of the wire rod, by mass percentage, includes: C: 0.025-0.040%, Si ≤ 0.01%, Mn: 0.30-0.40%, S ≤ 0.01%, P ≤ 0.01%, Al ≤ 0.005%, O ≤ 0.004%, N ≤ 0.005%, [Cr]+[Ni]+[Cu] ≤ 0.15%, [Sn]+[As]+[Sb] ≤ 0.01%, and at least one of V, Nb, and Ti is added, with [V]+[Nb]... +[Ti]=0.02-0.05%, with the addition of at least one rare earth element Ce or La, [Ce]+[La]=0.01-0.03%, ([Ce]+[La]) / [S]≥2.5, and the remainder being Fe and unavoidable impurities; wherein, [Cr], [Ni], [Cu], [Sn], [As], [Sb], [V], [Nb], [Ti], [Ce], [La], and [S] are the mass percentages of the corresponding elements in the wire rod.

12. The method for producing wire rod according to claim 11, characterized in that, The diameter of the wire rod is 5.5-6.5 mm; the tensile strength is 270-340 MPa; the reduction of area is ≥85%; the elongation is ≥45%; the size of transverse and longitudinal inclusions is ≤15 μm; the volume fraction of ferrite in the wire rod structure is 98-100%; and the ferrite grain size is 35-45 μm.

13. A method for weaving wire rod into a mesh, characterized in that, The wire rod produced by the wire rod production method according to any one of claims 10-12 undergoes descaling → boronizing treatment → rough drawing → first intermediate heat treatment → intermediate drawing → second intermediate heat treatment → galvanizing and aluminum plating → fine drawing → wire mesh weaving, wherein... In the rough drawing process, the wire rod is drawn 12-14 times to a diameter of 2.8-3.2mm. In the first heat treatment process, heat treatment is carried out in a protective atmosphere of mixed gas of N2 and H2, the heat treatment temperature is 680-700℃, the holding time is 2.5-3.0h, and then the furnace is cooled to 500℃ and then air-cooled. In the intermediate drawing process, the wire is drawn 8-10 times to continue drawing until the diameter is 1.6-1.8mm; In the second heat treatment process, heat treatment is carried out in a protective atmosphere of mixed gas of N2 and H2, with a heat treatment temperature of 660-680℃ and a holding time of 2.0-2.5h. After cooling in the furnace to 500℃, it is air-cooled. In the fine drawing process, the wire is drawn 15-18 times to continue drawing until the diameter is 0.3-0.7mm; During the netting process, the weaving speed is 20-45 rpm.

14. The wire rod weaving method according to claim 13, characterized in that, In the descaling process, a curved straightening roller is used in conjunction with a stainless steel wire brush for mechanical descaling. The contact pressure between the stainless steel wire brush and the wire rod surface is 0.3-0.5 MPa, and the roller speed is 800-1200 rpm. After mechanical descaling, the surface roughness R of the wire rod is [not specified]. a ≤3.2μm, oxide scale removal rate 89-95%; then pickled with 12-16% hydrochloric acid for 4-6 min; In the boronizing process, a borax solution with a concentration of 8-12% and a temperature of 85-95℃ is used for immersion coating for 1-3 minutes, followed by hot air drying at 120-150℃ for 5-8 minutes.

15. The wire rod weaving method according to claim 14, characterized in that, In the zinc-aluminum plating process, the steel wire, after intermediate drawing and a second heat treatment, is pickled in 8-12% hydrochloric acid for 1-3 minutes, then fluxed in a 30-40% ZnCl2·2NH4Cl mixed aqueous solution at 60-80℃ for 15-20 seconds. The fluxed steel wire is then dried in hot air at 120-150℃ for 2-3 minutes. After fluxing, the steel wire is immersed in a hot-dip galvanizing melt at 430-450℃ for 3-5 seconds, with the coating weight controlled at 100-150 g / m². 2 The hot-dip galvanized melt comprises, by mass percentage: Al: 5-7%, Ce / La: 0.03-0.05%, with the remainder being Zn.

16. The wire rod weaving method according to claim 15, characterized in that, The tensile strength of the steel wire is 650-900MPa, and the flatness of the woven mesh is ≤0.5mm / m. 2 The head breakage rate is ≤ 1 time / 100,000 meters.

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