Steel wire manufacturing method, tire bead steel wire, cable and rubber product

Abstract

The invention discloses a steel wire manufacturing method, a tire bead steel wire, a cable and a rubber product, and relates to the technical field of steel wire manufacturing. The method comprises the steps that the waste tires are subjected to heat treatment at the temperature of at least 150 DEG C, so that rubber is removed, metal fibers are recycled, and the mass fraction of non-metallic elements in the metal fibers does not exceed 15%; a steel raw material containing at least 1% by mass of metal fibers is adopted, and a wire rod with the diameter ranging from 4 mm to 7 mm is manufactured; and the wire rod is subjected to drawing treatment, and the steel wire is obtained. According to the method, the waste steel wires recovered from the waste tires are fully utilized, and the content of the copper element which has the greatest harm to the performance of the prepared steel wires is controlled from the source, so that the prepared steel wires have excellent fatigue performance, and efficient recovery and sustainable utilization of resources are realized.

Description

Technical Field

[0001] This invention relates to a method for manufacturing steel wire, tire bead wire, cable, and rubber products, belonging to the field of steel wire manufacturing technology. Background Technology

[0002] Currently, in steel wire manufacturing processes, especially for reinforcing rubber products, the steel must be chemically pure with minimal residual element content. Two main steelmaking processes exist: the blast furnace route, which uses ore as the primary raw material, producing high-purity steel but with high carbon dioxide emissions. While adding some scrap steel (≤30%) can reduce environmental impact, the limited scrap steel percentage makes further emission reduction difficult. The electric arc furnace route, on the other hand, uses a large amount of scrap steel (even 100%), significantly reducing emissions. However, residual elements in the scrap steel (such as copper and nickel) can enter the steel, leading to decreased purity, increased processing difficulty, and impaired fatigue performance. Existing technologies attempt to use steel wire recycled from waste tires as raw material to achieve a circular economy. However, the surface of steel wire in tires is usually coated with a copper alloy layer, resulting in a high copper content in the recycled material. Copper is difficult to remove during smelting, and its residue severely affects the steel wire's performance (especially fatigue performance), thus greatly limiting the proportion of such recycled materials used. Summary of the Invention

[0003] The purpose of this invention is to provide a method for manufacturing steel wire, tire bead wire, cable, and rubber products. By making full use of the waste steel wire components recycled from waste tires, the content of copper, which has the greatest impact on the performance of the prepared steel wire, is controlled at the source, so that the prepared steel wire has excellent fatigue performance.

[0004] To achieve the above objectives, the present invention is implemented using the following technical solution.

[0005] On one hand, the present invention provides a method for manufacturing steel wire, comprising at least the following steps:

[0006] Step S1: Heat-treat the waste tires at a temperature of at least 150°C to remove rubber and recover metal fibers, wherein the mass fraction of non-metallic elements in the metal fibers does not exceed 15%;

[0007] Step S2: Using steel raw materials containing at least 1% by mass of metal fibers, wire rods with a diameter of 4mm to 7mm are manufactured;

[0008] Step S3: The wire rod is drawn to obtain steel wire.

[0009] Optionally, in step S1, the heat treatment is a thermal decomposition operation.

[0010] Optionally, in step S2, steel raw materials with a mass fraction of 80%-100% metal fibers are used to manufacture wire rods with a diameter of 4mm to 7mm.

[0011] Optionally, the mass fraction of Cu in the metal fiber does not exceed 0.1%.

[0012] Optionally, the chemical composition of the wire rod obtained in step S2, expressed as a mass fraction, is as follows:

[0013] C: 0.05% to 1.1%;

[0014] Mn: 0% to 1%;

[0015] Si: 0% to 1%;

[0016] P: 0% to 0.03%;

[0017] S: 0% to 0.03%;

[0018] Cu: 0% to 0.1%;

[0019] Ni: 0% to 0.3%;

[0020] Cr: 0% to 0.3%;

[0021] Mo: 0% to 0.05%;

[0022] The mass fractions of Sn, As, N, and Al are all less than 0.01%;

[0023] The balance consists of Fe and impurities.

[0024] Optionally, step S2 includes steelmaking operations in an electric furnace.

[0025] Optionally, step S3 includes drawing a wire rod with a diameter of d0 to obtain a metal wire with a diameter of d1, where d1 is 0.6 mm to 3 mm.

[0026] Optionally, after drawing the wire rod with a diameter of d0 into a metal wire with a diameter of d1, the process further includes:

[0027] A metal coating is formed on the surface of a metal wire with a diameter of d1. The metal coating is selected from one of copper, zinc, nickel, cobalt, tin, iron, aluminum, and manganese, or an alloy of any two or any three of them.

[0028] Optionally, step S3 further includes: drawing a metal wire with a diameter of d1 to obtain a steel wire with a diameter of d2, wherein d2 is 0.06 mm to 0.5 mm.

[0029] In a second aspect, the present invention provides a bead wire comprising a metal wire obtained according to any one of the methods described in the first aspect.

[0030] Thirdly, the present invention provides a cable comprising a combination of steel wires obtained according to any one of the methods in the first aspect.

[0031] Fourthly, the present invention provides a rubber article configured with at least one of a metal wire, a steel wire, or a combination of steel wires obtained according to any one of the methods described in the first aspect.

[0032] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0033] In this invention, waste tires are treated with heat treatment at at least 150°C, which allows the copper alloy coating on the metal fibers to fully react with the rubber, reducing the copper content in the recycled metal fibers. This enables the metal fibers to be recycled in a high proportion or even 100% for steelmaking and further reuse, resulting in steel wires with excellent fatigue performance. At the same time, it effectively reduces CO2 emissions and dependence on non-renewable resources such as iron ore, achieving efficient resource recycling and sustainable utilization. Attached Figure Description

[0034] Figure 1 A schematic diagram of the manufacturing method of steel wire provided in an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of the torsional bending fatigue test results of a 0.30mm steel wire provided in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the torsional bending fatigue test results of a 3×0.25mm cable provided in an embodiment of the present invention. Detailed Implementation

[0037] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0038] Example 1

[0039] This embodiment describes a method for manufacturing steel wire, such as... Figure 1 As shown, it includes at least the following steps:

[0040] Step S1: Recycle metal fibers:

[0041] Waste tires are heat-treated at a temperature of at least 150°C to remove rubber and recover metal fibers. The heat treatment is preferably a pyrolysis operation, for example, carried out at 300°C. This method is well-known to those skilled in the art for separating rubber and metal fibers from tires. The recovered metal fibers contain no more than 15% by mass of non-metallic elements, and the mass fraction of Cu is specifically controlled to be no more than 0.1%.

[0042] Step S2, Manufacturing wire rod:

[0043] Using steel raw materials containing at least 1% (preferably 80%-100%) of the aforementioned metal fibers, wire rods with a diameter of 4mm to 7mm are manufactured through processes such as electric arc furnace steelmaking. The chemical composition of these wire rods by mass fraction is as follows:

[0044] C: 0.05% to 1.1%;

[0045] Mn: 0% to 1%;

[0046] Si: 0% to 1%;

[0047] P: 0% to 0.03%;

[0048] S: 0% to 0.03%;

[0049] Cu: 0% to 0.1%;

[0050] The content of elements Ni and Cr is less than 0.3% each, the content of elements Sn, As, N and Al is less than 0.01% each, the content of element Mo is less than 0.05%, and the remaining components of the steel are iron and unavoidable impurities.

[0051] The advantages of using recycled metal fibers to manufacture wire rods are: higher raw material quality and easier control of composition. Even if elements such as Zn, C, S, and Si may be introduced during the recycling process, these can be controlled during the steelmaking process. However, Cu is difficult to remove in conventional steelmaking, so it is necessary to focus on limiting its upper limit.

[0052] Step S3: Drawing the wire into steel wire:

[0053] The obtained wire rod is then drawn: First, the wire rod with a diameter of d0 is drawn to obtain a metal wire with a diameter of d1 (0.6 mm to 3 mm). A metal coating can then be formed on the surface of this metal wire. The coating can be selected from one of copper, zinc, nickel, cobalt, tin, iron, aluminum, and manganese, or an alloy of any two or any three. In this embodiment, a copper-zinc binary alloy is preferred. The coating method can be electroplating or chemical plating. Finally, the metal wire with a diameter of d1 is drawn to obtain a steel wire with a diameter of d2 (0.06 mm to 0.5 mm).

[0054] The drawing process is achieved by passing the metal wire through multiple drawing dies with gradually decreasing diameters. The number of drawing dies and the number of times the diameter d1 of the metal wire decreases successively depend on the ductility of the metal wire and the target diameter of the wire to be achieved. The smaller the diameter d2 of the wire, the more drawing dies are required.

[0055] To demonstrate the superior performance of the steel wire prepared using this method, a rotational bending test was conducted to assess its fatigue properties, characterizing its brittleness. The rotational bending test is a known fatigue test, and its principle is as follows: A steel wire sample of a certain length is held in two parallel jaws at both ends. The jaws cause the wire to bend, and the bending stress varies with the radius of curvature, which in turn depends on the length of the wire sample and the distance between the two jaws. In the first jaw, the wire can rotate freely, while in the second jaw, it remains fixed. The second jaw is electrically driven to rotate, causing the wire to continuously rotate and bend until it breaks, or reaches a stress of 10°. 6 Stop after one cycle and record the number of cycles. The rotational bending test can also be applied to cable inspection to characterize the fatigue performance of cables. The specific testing process and results are as follows:

[0056] In this embodiment, a φ5.50mm wire rod is made from raw materials containing 35% recycled metal fibers and drawn into 0.30mm steel wire.

[0057] Using 0.3mm steel wire produced from conventional wire rod using the same process as Comparative Example 1, a rotational bending fatigue test was conducted. The results showed that, under similar cycle counts, the fatigue performance of the steel wire obtained in this embodiment was comparable to that of Comparative Example 1. Figure 2 As shown, the vertical axis represents the number of cycles, and the horizontal axis represents different bending stresses, indicating that the steel wire made from recycled metal fibers has fatigue resistance similar to that of steel wire made from traditional raw materials.

[0058] Example 2

[0059] Based on the same inventive concept as Example 1, this example describes the manufacture of a φ5.50mm wire rod using 100% recycled metal fiber raw materials, which is then drawn into 0.25mm steel wire and twisted into a 3×0.25mm cable. A cable with the same structure, manufactured from conventional wire rod using the same process, is used as Comparative Example 2. Rotational bending fatigue testing shows that the fatigue performance of the cable obtained in this example is basically consistent with that of Comparative Example 2. Figure 3 As shown, the vertical axis represents the number of cycles, and the horizontal axis represents different bending stresses. As the number of cycles increases, the bending stress gradually decreases, further verifying that the steel wires and cables produced by this method can reach the level of traditional products in terms of fatigue performance.

[0060] Example 3

[0061] Based on the same inventive concept as other embodiments, this embodiment describes a vehicle bead wire comprising a metal wire with a diameter of d1 (0.6 mm to 3 mm) obtained according to the method described in Embodiment 1.

[0062] Example 4

[0063] Based on the same inventive concept as other embodiments, this embodiment introduces a cable, particularly a steel cord, which comprises a combination of steel wires with a diameter of d2 (0.06 mm to 0.5 mm) obtained according to the method described in the embodiment. The cable can be a single wire or multiple wires twisted together to form different structures, such as 1×1, 1×2, 1×3, 1×4, 1×5, 2+2, 3+9, 3×7, 7×7+1, etc., which are well known to those skilled in the art.

[0064] Cables reinforced with rubber products selected from vehicle tires, tracks, and conveyor belts.

[0065] Example 5

[0066] Based on the same inventive concept as other embodiments, this embodiment describes a rubber article configured with a reinforcement obtained according to the method described in Embodiment 1, such as the bead wire described in Embodiment 3, or the cable described in Embodiment 4, to enhance the performance of the rubber article; the rubber article can be selected from vehicle tires, tracks, or conveyor belts, and the specific configuration includes:

[0067] In a vehicle tire: the bead wires are disposed in the bead reinforcement layer of the tire to provide high rigidity support; the cables are disposed in the belt layer and / or carcass ply of the tire to provide high-strength skeletal reinforcement.

[0068] In tracks: The cables are embedded in the rubber matrix of the tracks of engineering machinery or heavy vehicles, serving as a reinforcing skeleton that resists tension and impact.

[0069] In a conveyor belt: the cable serves as a longitudinal reinforcement or tensile layer, disposed within the rubber belt body of a high-strength conveyor belt, to enhance the belt body's tensile strength, impact resistance, and fatigue resistance.

[0070] In summary, in this invention, waste tires are treated with a heat treatment process of at least 150°C, which allows the copper alloy coating on the metal fibers to fully react with the rubber, reducing the copper content in the recycled metal fibers. This enables the metal fibers to be recycled at a high or even 100% rate for steelmaking and further reused, resulting in steel wires with excellent fatigue performance. At the same time, it effectively reduces CO2 emissions and dependence on non-renewable resources such as iron ore.

[0071] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for manufacturing steel wire, characterized in that, At least the following steps are included: Step S1: Heat-treat the waste tires at a temperature of at least 150°C to remove rubber and recover metal fibers, wherein the mass fraction of non-metallic elements in the metal fibers does not exceed 15%; Step S2: Using steel raw materials containing at least 1% by mass of metal fibers, wire rods with a diameter of 4mm to 7mm are manufactured; Step S3: The wire rod is drawn to obtain steel wire.

2. The method for manufacturing steel wire according to claim 1, characterized in that, In step S1, the heat treatment is a thermal decomposition operation.

3. The method for manufacturing steel wire according to claim 2, characterized in that, In step S2, steel raw materials with 80%-100% mass fraction of metal fibers are used to manufacture wire rods with a diameter of 4mm to 7mm.

4. The method for manufacturing steel wire according to claim 3, characterized in that, The mass fraction of Cu in the metal fiber does not exceed 0.1%.

5. The method for manufacturing steel wire according to claim 4, characterized in that, The wire rod obtained in step S2 has the following chemical composition, expressed as a mass fraction: C: 0.05% to 1.1%; Mn: 0% to 1%; Si: 0% to 1%; P: 0% to 0.03%; S: 0% to 0.03%; Cu: 0% to 0.1%; Ni: 0% to 0.3%; Cr: 0% to 0.3%; Mo: 0% to 0.05%; The mass fractions of Sn, As, N, and Al are all less than 0.01%; The balance consists of Fe and impurities.

6. The method for manufacturing steel wire according to claim 5, characterized in that, Step S2 includes the steelmaking operation in an electric furnace.

7. The method for manufacturing steel wire according to claim 6, characterized in that, Step S3 includes drawing a wire rod with a diameter of d0 to obtain a metal wire with a diameter of d1, where d1 is 0.6 mm to 3 mm.

8. The method for manufacturing steel wire according to claim 7, characterized in that, After drawing the wire rod with a diameter of d0 into a metal wire with a diameter of d1, the process also includes: A metal coating is formed on the surface of a metal wire with a diameter of d1. The metal coating is selected from one of copper, zinc, nickel, cobalt, tin, iron, aluminum, and manganese, or an alloy of any two or any three of them.

9. The method for manufacturing steel wire according to claim 8, characterized in that, Step S3 further includes: drawing a metal wire with a diameter of d1 to obtain a steel wire with a diameter of d2, wherein d2 is 0.06mm to 0.5mm.

10. A bead wire comprising a metal wire obtained by the method according to any one of claims 1 to 9.

11. A cable comprising a combination of steel wires obtained by the method according to any one of claims 1 to 9.

12. A rubber product, characterized in that, The rubber product is configured with at least one of a metal wire, a steel wire, or a combination of steel wires obtained by the method according to any one of claims 1 to 9.

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