A stress corrosion resistant anchor cable and method of making the same

Abstract

The embodiment of the application discloses an anti-stress corrosion anchor cable and a preparation method thereof, and relates to the technical field of mine engineering supporting materials.The anchor cable comprises the following chemical components in percentage by mass: C: 0.75-0.85%, Si: 0.20-0.31%, Mn: 0.72-0.91%, P: 0.009-0.018%, S: 0.0055-0.0065%, Cr: 0.19-0.30%, Ni: 0.016-0.025%, V: 0.033-0.039%, Mg: 0.0004-0.0008%, Nb<=0.0005%, Al: 0.0021-0.0029%, Ca: 0.0003-0.0006%, Sn: 0.0005-0.0010%, Co: 0.0051-0.0062%, Ti: 0.0034-0.0039%, Gd<=0.0005%, and the rest is Fe and inevitable impurities.The embodiment of the application is suitable for mine engineering supporting scenes.

Description

Technical Field

[0001] This application relates to the field of mining engineering support materials technology, and in particular to a stress corrosion resistant anchor cable and its preparation method. Background Technology

[0002] As a core anchoring structure for controlling the surrounding rock in mining engineering, anchor cables face increasingly harsh service environments as mining activities continue to move into deeper strata. They not only endure long-term high stress but are also continuously exposed to mine water environments rich in corrosive media such as chloride ions, sulfides, carbonates, and microorganisms. The continuous coupling effect of high tensile stress loads and corrosive media significantly increases the risk of stress corrosion cracking in anchor cables. Measures such as improving the strength and toughness of the anchor cable steel matrix or increasing the density of anchor cables are insufficient to fundamentally solve the failure problem caused by the synergistic effect of high stress and a highly corrosive environment. Summary of the Invention

[0003] In view of this, embodiments of this application provide a stress corrosion resistant anchor cable and a method for preparing the same, which facilitates improving the stress corrosion resistance of the anchor cable.

[0004] In a first aspect, embodiments of this application provide a stress corrosion resistant anchor cable, comprising the following chemical composition by mass percentage: C: 0.75~0.85%, Si: 0.20~0.31%, Mn: 0.72~0.91%, P: 0.009~0.018%, S: 0.0055~0.0065%, Cr: 0.19~0.30%, Ni: 0.016~0.025%, V: 0.033~0 0.039%, Mg: 0.0004~0.0008%, Nb≤0.0005%, Al: 0.0021~0.0029%, Ca: 0.0003~0.0006%, Sn: 0.0005~0.0010%, Co: 0.0051~0.0062%, Ti: 0.0034~0.0039%, Gd≤0.0005%, the remainder being Fe and unavoidable impurities.

[0005] Optionally, the mass percentage of the chemical composition is as follows: C: 0.79%, Si: 0.25%, Mn: 0.81%, P: 0.015%, S: 0.062%, Cr: 0.25%, Ni: 0.021%, V: 0.037%, Mg: 0.0005%, Nb: 0.0003%, Al: 0.0025%, Ca: 0.0005%, Sn: 0.0006%, Co: 0.0056%, Ti: 0.0036%, Gd: 0.0003%, with the remainder being Fe and unavoidable impurities.

[0006] Optionally, the mass percentage of the chemical composition is as follows: C: 0.81%, Si: 0.27%, Mn: 0.84%, P: 0.011%, S: 0.059%, Cr: 0.22%, Ni: 0.022%, V: 0.036%, Mg: 0.0006%, Nb: 0.0002%, Al: 0.0026%, Ca: 0.0004%, Sn: 0.0008%, Co: 0.0058%, Ti: 0.0039%, Gd: 0.0001%, with the remainder being Fe and unavoidable impurities.

[0007] Optionally, the Cr:Ni mass ratio is greater than or equal to 7, and / or the Cr:V mass ratio is greater than or equal to 4.

[0008] Optionally, the surface of the anchor cable is plated with a zinc layer, and the zinc layer is coated with epoxy resin.

[0009] Secondly, embodiments of this application provide a method for preparing the anchor cable described in the first aspect, comprising the following steps: preparing raw materials according to the chemical composition of the stated mass percentage, smelting the raw materials to obtain a steel billet, heating the steel billet to a first temperature and holding it at that temperature for a first time to fully austenitize the steel billet, and then cooling the austenitized steel billet to a second temperature at a target rate; performing hot rolling treatment on the steel billet a specified number of times to obtain wire, spray cooling the wire to a third temperature, and cold drawing the wire to a target diameter to obtain a steel wire; using pickling solution to remove rust from the steel wire, and then drying it; immersing the steel wire in a fluxing solution at a first specified temperature for a second time, then immersing the steel wire in a zinc bath at a second specified temperature for a third time, removing the steel wire and water cooling it to a third specified temperature, removing the steel wire and drying it; twisting the dried steel wire with a predetermined helix angle and a predetermined number of strands to obtain an anchor cable.

[0010] Optionally, after obtaining the anchor cable, the method further includes the steps of: pre-treating, rinsing and drying the anchor cable; and coating the surface of the anchor cable with an epoxy resin coating of a specified thickness.

[0011] Optionally, the zinc liquid contains aluminum, and the aluminum in the zinc liquid reacts preferentially with the steel wire. The iron-aluminum alloy layer formed during the reaction can adhere to the surface of the steel wire, thereby inhibiting the formation of an iron-zinc alloy layer on the surface of the steel wire.

[0012] Optionally, the flux is zinc ammonium chloride at a concentration of 200-300 g / L, and the mass fraction of aluminum in the zinc solution is 0.11-0.15%.

[0013] Optionally, the first temperature range is 1100~1200℃, the first time is 1~2h, the target rate is 5~8℃ / s, the second temperature is 780~820℃, the specified number of times is 8~12, the third temperature is 400~440℃, the target diameter is 10~15mm, and the pickling solution formula is: citric acid mass fraction of 1%~3%, pH of 3~4, and corrosion inhibitor Lan-826 mass fraction of 0.1%~0.2%; the first specified temperature is 50~70℃, the second time is 2~3min, the second specified temperature is 460~480℃, the third time is 5~10s, the third specified temperature is 40~50℃, the predetermined helix angle is 15~25°, and the predetermined number of strands is 7 or 19.

[0014] This application provides a stress corrosion resistant anchor cable and its preparation method. Based on ordinary anchor cables, multiple alloying elements are added, so that the stress corrosion resistant microalloyed anchor cable prepared according to the above-mentioned chemical composition formula in mass percentage has stable mechanical properties, which is convenient to improve the stress corrosion resistance of the anchor cable and facilitates the solution of the failure problem of anchor cables caused by the synergistic effect of high stress and strong corrosion environment in mines. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a method for preparing an anchor cable according to an embodiment of this application;

[0017] Figure 2 This is a graph showing the relationship between the applied tensile load, the percentage of yield strength, and the fracture time for the anchor cables obtained in Embodiment 3 and Comparative Example 1 of this application.

[0018] Figure 3 This is a graph showing the relationship between the applied tensile load and yield strength percentage and the fracture time of the anchor cable obtained in Embodiment 4 and Comparative Example 2 of this application. Detailed Implementation

[0019] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0020] It should be understood that the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of the embodiments of this application.

[0021] Example 1:

[0022] This application provides a stress corrosion resistant anchor cable, comprising the following chemical composition by mass percentage: C: 0.75~0.85%, Si: 0.20~0.31%, Mn: 0.72~0.91%, P: 0.009~0.018%, S: 0.0055~0.0065%, Cr: 0.19~0.30%, Ni: 0.016~0.025%, V: 0.033~0.0 39%, Mg: 0.0004~0.0008%, Nb≤0.0005%, Al: 0.0021~0.0029%, Ca: 0.0003~0.0006%, Sn: 0.0005~0.0010%, Co: 0.0051~0.0062%, Ti: 0.0034~0.0039%, Gd≤0.0005%, the remainder being Fe and unavoidable impurities.

[0023] Current engineering standards only mandate that anchor cable steel strands meet specific strength requirements, but lack mandatory requirements for their corrosion resistance in highly corrosive environments. This directly leads to severe challenges to the structural integrity of anchor cables when operating in the highly corrosive environment of deep mines. Anchor cable failure not only results in the complete loss of its anchoring function but also easily induces surrounding rock instability, causing roof falls and spalling accidents in roadways, resulting in significant economic losses. Simply relying on measures such as improving the strength and toughness of the anchor cable steel matrix or increasing the arrangement density is insufficient to fundamentally solve the failure problem caused by the synergistic effect of high stress and highly corrosive environments. Even with a galvanized protective layer, anchor cables still face the risk of stress corrosion in highly corrosive mine water environments. In this embodiment, various alloying elements are added to the ordinary anchor cable, so that the stress corrosion resistant microalloyed anchor cable prepared according to the above-mentioned chemical composition formula in mass percentage has stable mechanical properties, which is conducive to improving the stress corrosion resistance of the anchor cable, solving the failure problem of anchor cable caused by the synergistic effect of high stress and strong corrosion environment in mine, improving the reliability and durability of anchoring structure and project, meeting the corrosion resistance requirements of mining engineering, and having good industrial and commercial prospects.

[0024] The content of the main alloying elements in this embodiment is based on the following principle:

[0025] C: Carbon is the main strengthening element in steel, increasing strength and hardness, but excessive amounts will reduce toughness. In anchor cables, an appropriate amount of carbon can enhance tensile strength; therefore, the C content in this embodiment is set at 0.75~0.85%.

[0026] Si: As a deoxidizer, it reduces oxide inclusions, enhances material density, and improves fatigue life. Therefore, the Si content in this embodiment is set at 0.20~0.31%.

[0027] Mn: deoxidizes and desulfurizes, refines grains; improves hardenability and impact toughness. Therefore, the Mn content in this embodiment is set at 0.72~0.91%.

[0028] P: Solid solution strengthening improves corrosion resistance, but excessive amounts can lead to cold brittleness. Therefore, the P content in this embodiment is set at 0.009 ~ 0.018%.

[0029] S: Forms MnS inclusions, balancing processing performance and material integrity. Therefore, the S content in this embodiment is set at 0.0055 ~ 0.0065%.

[0030] Cr: can form The oxide passivation film improves corrosion resistance and is suitable for anchoring in humid and corrosive environments. Therefore, the Cr content in this embodiment is set at 0.19~0.30% to improve the stress corrosion resistance of the formed anchor cable.

[0031] Ni: Solid solution strengthening improves toughness, enhances fatigue resistance, and prevents brittle fracture. Therefore, the Ni content in this embodiment is set at 0.016 ~ 0.025%.

[0032] V: refines grains and inhibits recrystallization; forms VN carbonitrides for strengthening, improving strength while maintaining toughness. Therefore, the V element content in this embodiment is set at 0.033 ~ 0.039%.

[0033] Mg: Deoxidizer, refines grain size; improves overall reliability. Therefore, the Mg content in this embodiment is set at 0.0004 ~ 0.0008%.

[0034] Nb: Precipitation strengthens and refines grains; inhibits austenite recrystallization. Therefore, the Nb content in this embodiment is set to ≤0.0005%.

[0035] Al: Deoxidizer, forming Inclusions enhance corrosion resistance and reduce the risk of intergranular corrosion. Therefore, in this embodiment, the Al content is set at 0.0021~0.0029% to improve the stress corrosion resistance of the anchor cable.

[0036] Ca: It changes the morphology of sulfides, improves toughness, optimizes the distribution of inclusions, and enhances impact resistance. Therefore, the Ca content in this embodiment is set at 0.0003 ~ 0.0006%.

[0037] Sn: Solid solution strengthening improves hardness, enhances surface wear resistance, and extends service life. Therefore, the Sn content in this embodiment is set at 0.0005 ~ 0.0010%.

[0038] Co: Improves high-temperature strength and corrosion resistance. Therefore, the Co content in this embodiment is set at 0.0051~0.0062% to improve the stress corrosion resistance of the anchor cable.

[0039] Ti: Refines grains, forms TiN / TiC reinforcing phases, enhances material density, and prevents stress corrosion. Therefore, the Ti content in this embodiment is set at 0.0034 ~ 0.0039% to improve the stress corrosion resistance of the anchor cable.

[0040] Gd: refines grain size; improves corrosion resistance; trace addition enhances overall performance. Therefore, in this embodiment, the Gd content is set to ≤0.0005% to improve the stress corrosion resistance of the anchor cable.

[0041] In some embodiments, the Cr:Ni mass ratio is greater than or equal to 7, and / or the Cr:V mass ratio is greater than or equal to 4.

[0042] In this embodiment, the mass ratio of Cr:Ni is greater than or equal to 7. The high proportion of Cr can be used to suppress chloride ion penetration, while an appropriate amount of Ni can be used to maintain the toughness of the structure in the formed steel, so as to avoid the failure of the passivation film of the anchor cable due to the internal structural stress. The mass ratio of Cr:V is greater than or equal to 4, so that the Cr content is sufficient to form a continuous passivation film. At the same time, the V content is controlled according to the above ratio to avoid excessive precipitation of carbides and maintain the integrity of the passivation film.

[0043] In some embodiments, the surface of the anchor cable is plated with a zinc layer, and the surface of the zinc layer is coated with epoxy resin.

[0044] In this embodiment, when galvanizing the anchor cable, a zinc-iron alloy layer is formed on the anchor cable surface to improve the anchor cable strength and provide chemical corrosion protection. Because under the combined effects of high stress and strong corrosion, even with a galvanized protective layer, the anchor cable is still at risk of stress corrosion failure in highly corrosive mine water environments. Therefore, in addition to the zinc plating, the anchor cable is also coated with epoxy resin to form a dense barrier on the surface, effectively blocking moisture, oxygen, chloride ions, and other chemically corrosive substances. This slows down the physical contact between chemically corrosive substances and the zinc layer and the anchor cable, reducing electrochemical corrosion and extending the service life of the anchor cable in humid, saline-alkali, or acidic-alkali environments. Simultaneously, the epoxy resin has high hardness and toughness, reducing surface damage caused by friction and rock compression during installation, tensioning, and service, thus maintaining structural integrity. During the installation and use of anchor cables, nylon slings or special bending pipes can be used for transportation and installation. If the epoxy resin coating is damaged during transportation or installation, it can be repaired in time with the matching epoxy repair liquid to reduce the corrosive substances entering the damaged area and reduce the corrosion of the zinc layer and anchor cable at the damaged area.

[0045] Example 2:

[0046] See Figure 1 This application provides a method for preparing an anchor cable as described in any of the embodiments of Embodiment 1, comprising the following steps:

[0047] S1. Prepare raw materials according to the chemical composition of the mass percentage, smelt the raw materials to obtain steel billets, heat the steel billets to a first temperature and hold them at that temperature for a first time to fully austenitize the steel billets, and then cool the austenitized steel billets to a second temperature at a target rate.

[0048] In this step, the raw materials are prepared according to the chemical composition of the mass percentage described in Example 1. This ensures that the steel billet obtained from the smelting of the raw materials prepared with the above chemical composition can effectively resist stress corrosion while meeting the engineering strength index. This effectively solves the failure problem of anchor cables in mines caused by the combined effect of high stress and strong corrosion environment. The steel billet is heated to a first temperature and held at that temperature for a first time to allow the steel billet to fully form an austenitic structure, even to the point of complete austenitization, thereby improving the toughness and corrosion resistance of the anchor cable prepared using the steel billet. The austenitized steel billet is then cooled to a second temperature at a target rate to prevent the austenitized structure within the steel billet from being destroyed, thus maintaining good mechanical and chemical properties.

[0049] S2. The steel billet is hot-rolled a specified number of times to obtain wire rod, the wire rod is spray-cooled to a third temperature, and the wire rod is cold-drawn to the target diameter to obtain steel wire.

[0050] In this step, heating the steel billet to the austenitizing temperature enhances atomic thermal motion and strengthens lattice slip. Hot rolling at high temperatures helps break up coarse cast grains and increase fine grains, thereby improving the strength and toughness of the billet. At the same time, high-temperature diffusion reduces chemical segregation, allowing alloying elements to be evenly distributed within the billet. It can also repair original defects such as stress or shrinkage cavities within the billet, improving material integrity. Simultaneously, it reduces wear and energy consumption of the rolling mill equipment, increasing the mill's production efficiency. Cold drawing of wire rod directly reduces cutting waste and saves steel. During the cold drawing process, the wire rod undergoes plastic deformation, hindering lattice slip, which significantly improves the tensile strength and yield strength of the resulting steel wire.

[0051] S3. Use pickling solution to remove rust from the steel wire, and then dry it.

[0052] In this step, the pickling solution is used to clean and remove rust from the surface of the steel wire, and the formation of a passivation protective film can effectively improve the corrosion resistance of the steel wire. Then the steel wire is dried to prevent the pickling solution residue on the steel wire from remaining for too long and reacting chemically with substances in the air to corrode the steel wire.

[0053] S4. Immerse the steel wire in a flux solution at a first specified temperature for a second time, then immerse the steel wire in zinc solution at a second specified temperature for a third time. After removing the steel wire, water cool it to a third specified temperature, and then dry it.

[0054] In this step, the steel wire is immersed in the flux solution at a first specified temperature and held for a second time. This allows the flux solution to form a zinc chloride ammonium salt film on the surface of the steel wire. This maintains the metal surface in an activated state, ensuring direct reaction between the zinc solution and the steel wire, improving the adhesion of the zinc coating, reducing zinc plating time and zinc solution consumption, and also improving the zinc plating effect. At the same time, it can also remove iron salt residues. Iron salt residues may exist on the steel wire. If these residues are not removed, they will accelerate the aging of the zinc solution, leading to incomplete plating or a rough coating.

[0055] S5. Twist the dried steel wire with a predetermined helix angle and a predetermined number of strands to obtain an anchor cable.

[0056] In this step, when twisting steel wires to form anchor cables, the more strands there are, the more uniform the distribution of steel wires, and the more steel wires per unit area, the higher the overall tensile strength and toughness of the resulting anchor cable. Multiple strands (such as 20 to 200 strands) are suitable for scenarios requiring high flexibility, such as large engineering machinery or power transmission, while fewer strands (such as 6 to 19 strands) are suitable for scenarios with high load and low bending requirements. A larger helix angle increases friction and stress concentration between steel wires, reducing fatigue life, while a smaller helix angle makes the anchor cable stronger in torsional resistance, suitable for scenarios where axial tension is the primary load.

[0057] In some embodiments, after obtaining the anchor cable, the steps further include: pre-treating the anchor cable surface, rinsing and drying it; and coating the surface of the anchor cable with an epoxy resin coating of a specified thickness.

[0058] In this step, before coating the anchor cable with epoxy resin, the anchor cable undergoes surface pretreatment, followed by rinsing and drying. Surface pretreatment includes, but is not limited to, lightly grinding the anchor cable surface with a grinder to remove any possible oxide scale or other contaminants, increasing the physical adhesion between the anchor cable and the epoxy resin coating. Sandblasting or other methods can further improve the cleanliness of the anchor cable surface. After surface pretreatment, impurities may remain on the anchor cable surface or in the wire gaps; rinsing the anchor cable with water removes these impurities. To ensure the effectiveness of subsequent coating processes, the anchor cable must be thoroughly dried before applying the epoxy resin coating. Specifically, the anchor cable can be placed in a dedicated drying device, heated to a predetermined temperature using a temperature control device, and maintained at that temperature. Allow the anchor cable surface to dry completely for a certain period of time. The key to this step is to thoroughly remove moisture and impurities from the anchor cable surface to avoid affecting the adhesion of the subsequent epoxy resin coating. Before applying epoxy resin to the anchor cable, it can also be preheated to bring the anchor cable temperature close to the optimal application temperature range of the epoxy resin, thereby reducing the generation of air bubbles in the coating and improving the overall uniformity of the coating. To reduce the direct contact between the anchor cable and corrosive substances in the working environment, an epoxy resin coating of a specified thickness is applied to the surface of the anchor cable. The epoxy resin coating has high hardness and toughness, and excellent resistance to acid, alkali, and salt corrosion. It can effectively physically isolate the anchor cable from surrounding corrosive substances, delaying corrosion caused by direct contact between the anchor cable surface metal and surrounding corrosive substances, and improving the service life of the anchor cable.

[0059] In some embodiments, the steel wire surface can be galvanized using flux and zinc solution as described above, and then the galvanized steel wire can be twisted to obtain an anchor cable with a zinc coating. Alternatively, after twisting the steel wire into an anchor cable, the anchor cable can be galvanized to obtain an anchor cable with a zinc coating. This can reduce the consumption of flux and zinc solution to a certain extent.

[0060] In some embodiments, the thickness of the epoxy resin coating is set to 25~45μm to effectively isolate the anchor cable from surrounding corrosive substances.

[0061] In some embodiments, the zinc bath contains aluminum. The aluminum in the zinc bath preferentially reacts with the steel wire, and the resulting iron-aluminum alloy layer adheres to the surface of the steel wire, thus inhibiting the formation of an iron-zinc alloy layer on the steel wire surface. The presence of aluminum in the zinc bath allows for the preferential reaction with the steel wire, forming a complete and dense iron-aluminum alloy inhibition layer, ensuring the uniformity and thickness of the coating and preventing protrusions. Because aluminum and iron have a strong affinity, they more easily form an alloy layer. Therefore, the iron-aluminum alloy layer forms preferentially before the iron-zinc alloy layer, and this layer firmly adheres to the steel wire surface, acting as a medium to enhance the adhesion between the zinc coating and the steel base. Furthermore, the iron-aluminum alloy layer effectively inhibits the formation of an iron-zinc alloy layer on the steel wire surface, suppressing the excessive growth of the brittle iron-zinc alloy layer and significantly reducing its thickness. This results in a thinner and more resilient alloy coating on the steel wire surface. Then, zinc forms a zinc coating on the outer layer of the iron-aluminum alloy layer, providing better electrochemical corrosion protection for the steel wire.

[0062] In some embodiments, the flux is zinc ammonium chloride at a concentration of 200-300 g / L, and the aluminum mass fraction in the zinc bath is 0.11-0.15%. The flux can remove residual oxides after pickling of the steel wire, form a solvent protective film, prevent secondary oxidation, and ensure that the steel wire surface is in a pure iron active state. When the zinc ammonium chloride concentration in the flux is too low, it is difficult to form a sufficient solvent protective film, which easily leads to secondary oxidation. When the zinc ammonium chloride concentration in the flux is too high, there is too much solvent residue, which easily produces zinc ash during zinc plating, resulting in a rough coating or poor coating quality. When the aluminum content in the zinc bath is too low, the aluminum will not be able to form an iron-aluminum alloy layer that covers the steel wire surface. This process allows zinc to bond with the steel wire surface, forming a thicker iron-zinc alloy layer, increasing zinc consumption. However, excessive aluminum in the zinc bath can cause an over-reaction with the iron in the steel wire, generating brittle alloy phases. These brittle alloy phases are hard but lack toughness, leading to increased overall brittleness of the coating. Furthermore, excessive aluminum may react with other elements in the zinc bath to form intermetallic compounds, further reducing the coating's flexibility and ultimately making the zinc layer prone to cracking or peeling under stress. Using flux with the aforementioned mass concentration and zinc bath containing a specified mass fraction of aluminum can reduce coating thickness, increase the bonding strength between the coating and the steel wire, improve the coating's uniformity, corrosion resistance, and ductility, effectively enhancing the galvanizing effect of the steel wire.

[0063] In some embodiments, the first temperature range is 1100~1200℃, the first time is 1~2h, the target rate is 5~8℃ / s, the second temperature is 780~820℃, the specified number of times is 8~12, the third temperature is 400~440℃, and the target diameter is 10~15mm; the pickling solution formula is: citric acid mass fraction of 1%~3%, pH of 3~4, and corrosion inhibitor Lan-826 mass fraction of 0.1%~0.2%; the first specified temperature is 50~70℃, the second time is 2~3min, the second specified temperature is 460~480℃, the third time is 5~10s, the third specified temperature is 40~50℃, the predetermined helix angle is 15~25°, and the predetermined number of strands is 7 or 19.

[0064] In this embodiment, heating the steel billet to 1100~1200℃ and holding it at that temperature for 1~2 hours is beneficial for the full formation of an austenitic structure within the billet, improving the toughness and corrosion resistance of the anchor cable prepared using the billet. A slow cooling rate affects processing efficiency, while a fast cooling rate may cause the austenitic structure to be destroyed or transformed into other structures within the billet, or lead to internal stress within the billet, which is detrimental to the hardness and strength properties of the anchor cable and reduces its plasticity. Cooling at a target rate of 5~8℃ reduces the amount of ferrite formation, prolongs the bainite transformation period, avoids the excessive formation of martensite, and produces an ideal matrix structure, thereby improving the anchor cable's plasticity, toughness, corrosion resistance, and other mechanical and chemical properties. The second temperature is 780~820℃. When the billet cools to 780~820℃, a stable austenitic structure has formed inside, allowing for further processing and improving processing efficiency.

[0065] Specifying 8-12 hot rolling cycles on the steel billet significantly reduces its deformation resistance, ensures uniform distribution of alloying elements, improves material integrity, and avoids excessive oxide formation and performance degradation due to excessive hot rolling cycles. Spray cooling the wire rod to a third temperature of 400-450℃ induces precipitation strengthening of elements such as V and Nb, enhancing material strength and plasticity, and improving tensile strength. This temperature range is conducive to the dispersed distribution of nano-scale carbides within the wire rod. Uniform spray cooling reduces high-temperature oxide scale formation and avoids the formation of martensitic rings and surface rust caused by water cooling. Maintaining a target wire rod diameter of 10-15mm meets the needs of mining engineering support materials technology.

[0066] Citric acid, with a mass fraction of 1% to 3%, is used to clean and remove rust from the steel surface. During pickling, citric acid reacts chemically with oxides and rust layers on the steel surface, effectively cleaning and removing rust. Furthermore, the molecular structure of citric acid contains multiple hydroxyl and carboxyl groups, exhibiting excellent coordination ability and slow-release properties. This allows it to form a protective film on the steel surface during pickling, reducing acid corrosion of the steel substrate and improving the safety and selectivity of the pickling process. In addition, citric acid has good biodegradability and environmental friendliness. The pickling solution is adjusted to a pH of 3 to 4 to avoid excessively low pH levels that could corrode the steel wire while cleaning and removing rust. Combined with a corrosion inhibitor, Lan-826, with a mass fraction of 0.1% to 0.2%, the steel surface is protected from residual corrosion while removing rust.

[0067] The first specified temperature is 50~70℃, which facilitates the reaction between the flux and the steel wire surface. The second holding time is 2~3 minutes, allowing a sufficient zinc chloride ammonium salt film to form on the steel wire surface, thus improving the galvanizing effect. To ensure the galvanizing effect on the steel wire, the second specified temperature is set to 460~480℃, and the third holding time is 5~10 seconds, ensuring the steel wire surface is fully covered with a zinc layer while avoiding an excessively thick or thin coating. Setting the third specified temperature to 40~50℃ promotes the bonding between the zinc layer and the steel, forming a dense and uniform coating.

[0068] When the steel wire is twisted at a predetermined helix angle of 15~25°, the filling density of the anchor cable can be increased, the sealing performance can be enhanced, and the corrosion resistance of the anchor cable can be improved. In high-load scenarios, choosing to twist with a predetermined number of strands of 7 or 19 strands can ensure the strength and torsional resistance of the anchor cable, which is suitable for high-load and low-bending scenarios in the field of mining engineering support.

[0069] In some embodiments, the pickling solution may also be a sulfamic acid solution or a glycolic acid solution. Sulfamic acid is not highly corrosive and reacts with rust to form soluble salts, creating a protective film on the steel surface. Since sulfamic acid is easily hydrolyzed at high temperatures, the temperature should be controlled to ≤60°C during use. Glycolic acid is not highly corrosive and has a high efficiency in dissolving rust, but when used alone, it may leave residues on the steel surface, thus causing corrosion. It needs to be used in conjunction with a corrosion inhibitor (such as triethanolamine) to protect the steel surface from residual corrosion while removing rust.

[0070] In some embodiments, before using pickling solution to remove rust from steel, the surface of the steel wire is first treated to remove oil and loose rust; the pickling solution is heated to 40~60°C, and then the steel wire is immersed in the pickling solution for 10~60 minutes to complete the rust removal and cleaning process; then the pickled steel wire is neutralized, cleaned and passivated to remove residual acid from the surface of the steel wire and form a dense passivation protective film, thereby improving the corrosion resistance of the steel surface.

[0071] Example 3:

[0072] In some embodiments, the mass percentage of the chemical composition is as follows: C: 0.79%, Si: 0.25%, Mn: 0.81%, P: 0.015%, S: 0.062%, Cr: 0.25%, Ni: 0.021%, V: 0.037%, Mg: 0.0005%, Nb: 0.0003%, Al: 0.0025%, Ca: 0.0005%, Sn: 0.0006%, Co: 0.0056%, Ti: 0.0036%, Gd: 0.0003%, with the remainder being Fe and unavoidable impurities. A steel billet is obtained by smelting according to the above chemical composition. The steel billet is heated to 1150°C and held for 1.5 hours to achieve complete austenitization. The fully austenitized steel billet is then cooled to 780°C at a target rate of 5°C / s and hot-rolled eight times to obtain wire rod. The wire was spray-cooled to 400°C, then cold-drawn to 15mm to obtain steel wire. The wire was derusted using citric acid pickling solution, dried, and then immersed in a fluxing solution at 50°C for 2 minutes. The plated wire was then transferred to a zinc bath at 460°C and held for 5 seconds. After removing the anchor cable, it was cooled by immersion in water at 40°C. The wire was twisted into 19 strands at a 15° helix angle to obtain the anchor cable. Finally, a 45μm layer of epoxy resin was applied to the surface of the anchor cable to complete the anchor cable.

[0073] Example 4:

[0074] In some embodiments, the mass percentage of the chemical composition is as follows: C: 0.81%, Si: 0.27%, Mn: 0.84%, P: 0.011%, S: 0.059%, Cr: 0.22%, Ni: 0.022%, V: 0.036%, Mg: 0.0006%, Nb: 0.0002%, Al: 0.0026%, Ca: 0.0004%, Sn: 0.0008%, Co: 0.0058%, Ti: 0.0039%, Gd: 0.0001%, with the remainder being Fe and unavoidable impurities. A steel billet is obtained by smelting according to the above chemical composition. The steel billet is heated to 1200°C and held for 2 hours to achieve complete austenitization. The fully austenitized steel billet is then cooled to 820°C at a target rate of 8°C / s and hot-rolled 10 times to obtain wire rod. The wire was spray-cooled to 440°C, then cold-drawn to 15mm to obtain steel wire. The wire was derusted using citric acid pickling solution, dried, and then immersed in a fluxing solution at 70°C for 2.5 minutes. The plated wire was then transferred to a zinc bath at 480°C for 10 seconds. After removing the anchor cable, it was cooled by immersion in water at 50°C. The wire was twisted into 19 strands at a 15° helix angle to obtain the anchor cable. Finally, a 40μm layer of epoxy resin was applied to the surface of the anchor cable to obtain the final anchor cable.

[0075] Comparative Example 1:

[0076] A common anchor cable prepared with the following chemical composition by mass percentage: C: 0.72%, Si: 0.31%, Mn: 0.62%, Cr: 0.23%, with the remainder being Fe and unavoidable impurities, was used as control anchor cable 1.

[0077] Comparative Example 2:

[0078] An ordinary anchor cable prepared with the following chemical composition by mass percentage: C: 0.64%, Si: 0.26%, Mn: 0.66%, Cr: 0.26%, with the remainder being Fe and unavoidable impurities, was used as control anchor cable 2.

[0079] The anchor cables obtained in Examples 3, 4, 1, and 2 were tested, and their mechanical properties are shown in Table 1.

[0080]

[0081] As can be seen from Table 1, the anchor cables obtained in Embodiments 3 and 4 of this application have good strength performance. On the premise of ensuring that the strength requirements are met, the anchor cables also have corrosion resistance.

[0082] like Figure 2 and Figure 3As shown, in the simulated mine solution, Example 3 exhibits stronger corrosion resistance compared to Comparative Example 1, and Example 4 exhibits stronger corrosion resistance compared to Example 2. The anchor cables of Examples 3 and 4 can withstand long-term corrosion from the mine solution without breaking. When a tensile load of 105% of the anchor cable's yield strength is applied, the average fracture time of the anchor cables in this application is 20 times that of the ordinary anchor cables in Comparative Example 1 and Comparative Example 2, effectively improving the service life of the anchor cables under the combined effect of high stress and strong corrosion environment.

[0083] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0084] The above description is merely a specific implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be included within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. A stress corrosion resistant anchor cable, characterized in that, The chemical composition includes the following percentages by mass: C: 0.75~0.85%, Si: 0.20~0.31%, Mn: 0.72~0.91%, P: 0.009~0.018%, S: 0.0055~0.0065%, Cr: 0.19~0.30%, Ni: 0.016~0.025%, V: 0.033~0.039%, Mg: 0.0004~0.0008%, Nb≤0.0005%, Al: 0.0021~0.0029%, Ca: 0.0003~0.0006%, Sn: 0.0005~0.0010%, Co: 0.0051~0.0062%, Ti: 0.0034~0.0039%, Gd≤0.0005%, with the remainder being Fe and unavoidable impurities; The method for preparing the anchor cable includes the following steps: Raw materials are prepared according to the chemical composition of the mass percentage, and the raw materials are smelted to obtain steel billets. The steel billets are heated to a first temperature and held at that temperature for a first time to fully austenitize the steel billets. Then, the austenitized steel billets are cooled to a second temperature at a target rate. The steel billet is hot-rolled a specified number of times to obtain wire rod, the wire rod is spray-cooled to a third temperature, and the wire rod is cold-drawn to a target diameter to obtain steel wire. The steel wire was derusted using a pickling solution and then dried. The steel wire is immersed in a flux solution at a first specified temperature for a second time, then immersed in zinc solution at a second specified temperature for a third time. After the steel wire is removed, it is water-cooled to a third specified temperature, and then dried. The dried steel wire is twisted with a predetermined helix angle and a predetermined number of strands to obtain an anchor cable; The zinc liquid contains aluminum, and the aluminum in the zinc liquid reacts preferentially with the steel wire. The iron-aluminum alloy layer formed during the reaction can adhere to the surface of the steel wire, thereby inhibiting the formation of an iron-zinc alloy layer on the surface of the steel wire. Wherein, the first temperature range is 1100~1200℃, the first time is 1~2h, the target rate is 5~8℃ / s, the second temperature is 780~820℃, the specified number of times is 8~12, the third temperature is 400~440℃, the first specified temperature is 50~70℃, the second time is 2~3min, the second specified temperature is 460~480℃, the third time is 5~10s, and the third specified temperature is 40~50℃.

2. The anchor cable according to claim 1, characterized in that, The specific mass percentages of the chemical composition are as follows: C: 0.79%, Si: 0.25%, Mn: 0.81%, P: 0.015%, S: 0.062%, Cr: 0.25%, Ni: 0.021%, V: 0.037%, Mg: 0.0005%, Nb: 0.0003%, Al: 0.0025%, Ca: 0.0005%, Sn: 0.0006%, Co: 0.0056%, Ti: 0.0036%, Gd: 0.0003%, with the remainder being Fe and unavoidable impurities.

3. The anchor cable according to claim 1, characterized in that, The specific mass percentages of the chemical composition are as follows: C: 0.81%, Si: 0.27%, Mn: 0.84%, P: 0.011%, S: 0.059%, Cr: 0.22%, Ni: 0.022%, V: 0.036%, Mg: 0.0006%, Nb: 0.0002%, Al: 0.0026%, Ca: 0.0004%, Sn: 0.0008%, Co: 0.0058%, Ti: 0.0039%, Gd: 0.0001%, with the remainder being Fe and unavoidable impurities.

4. The anchor cable according to claim 1, characterized in that, The mass ratio of Cr:Ni is greater than or equal to 7, and / or the mass ratio of Cr:V is greater than or equal to 4.

5. The anchor cable according to claim 1, characterized in that, The anchor cable is plated with a zinc layer, and the zinc layer is coated with epoxy resin.

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