Novel structure coated steel wire and steel cord

Abstract

The application discloses a novel structure plated steel wire and a steel cord, and belongs to the technical field of steel wire structure. The novel structure plated steel wire comprises a steel wire and sequentially attached reinforcing layer, stabilizing layer and tackifying layer; the tackifying layer is a first alloy containing element A and element B; the stabilizing layer is a second alloy containing element A and element B or a substance containing only element B; and the reinforcing layer is a third alloy containing element A and element B; the attachment depth of the tackifying layer is a, the attachment depth of the stabilizing layer is b, the attachment depth of the reinforcing layer is c, the total attachment depth of each plated layer is d, and the attachment depth of each plated layer satisfies the following conditions: a+b+c=d, a>c>b, b+c

Description

Technical Field

[0001] This invention relates to a novel structural coated steel wire and steel cord, belonging to the field of steel wire structure technology. Background Technology

[0002] In the modern tire manufacturing industry, steel cord serves as the core reinforcing material, and its performance directly affects the quality and lifespan of tires. With the rapid development of the global automotive industry and the increasing demands of consumers for high-performance, long-life, and safe tires, even more stringent challenges are being placed on the overall performance of steel cord.

[0003] During tire use, the adhesion between the steel cords and rubber is crucial, directly affecting the tire's structural stability and lifespan. While existing brass plating can ensure the bond between the steel cords and rubber, this adhesion gradually decreases over long-term use, especially under harsh conditions such as high temperature, high humidity, and high load. This leads to the steel cords detaching from the rubber, severely impacting tire performance. This demonstrates the limitations of traditional steel cord plating technology in handling complex and changing operating environments. In special conditions involving high temperature, high humidity, and chemical corrosion, such as the hot and rainy roads in tropical regions and scenarios where chemical transport vehicles frequently come into contact with corrosive chemicals, the brass-based steel cord plating, due to its chemical composition and structural characteristics, is prone to corrosion. Elements in the plating react electrochemically with the surrounding medium, causing the plating to gradually erode and peel off, directly exposing the internal steel wires. This accelerates the corrosion of the steel wires, severely reducing the strength and toughness of the steel cords, shortening tire lifespan, and potentially posing safety hazards. Summary of the Invention

[0004] The purpose of this invention is to provide a novel structured coated steel wire and steel cord, solving the problem of poor corrosion resistance of steel wires in existing technologies. Simultaneously, through a unique coating structure design and manufacturing process, the bonding force between the steel wire and rubber is improved, enhancing the tensile and twisting properties of the steel wire.

[0005] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a novel structured coated steel wire, comprising a steel wire and a reinforcing layer, a stabilizing layer and an adhesive layer attached sequentially; The adhesive layer is a first alloy containing element A and element B; The stabilizing layer is a second alloy containing element A and element B or a substance containing only element B; The strengthening layer is a third alloy containing elements A and B; The adhesion depth of the tackifying layer is a, the adhesion depth of the stabilizing layer is b, the adhesion depth of the reinforcing layer is c, and the total adhesion depth of all coatings is d. The adhesion depth of each coating satisfies the following conditions: a+b+c=d, a>c>b, b+c<a, a / d>1 / 2, b / c<1 / 3.

[0006] Furthermore, the mass ratio of element A to element B in the first alloy is x, and satisfies the following condition: 1.778≤x≤2.030.

[0007] Furthermore, the mass ratio of element A to element B in the second alloy is y, and satisfies the following condition: y < 1.

[0008] Furthermore, the mass ratio of element A to element B in the third alloy is z, and satisfies the following condition: 1.564≤z≤1.740.

[0009] Furthermore, the total adhesion depth satisfies the following condition: 0.8μm≤d≤4.0μm.

[0010] Furthermore, when the stabilizing layer is a second alloy containing elements A and B, each coating layer is attached in the following manner: The elements A, B, and A are plated sequentially, and then thermally heated to form a three-phase alloy, resulting in the corresponding coating. The amount of element A plated closer to the steel wire is less than the amount of element A plated further away from the steel wire.

[0011] Furthermore, when the stabilizing layer is a substance containing only element B, the tackifying layer and the reinforcing layer are attached by co-plating elements A and B.

[0012] Furthermore, the stabilizing layer is formed by electrolysis in a plating solution containing nano-zinc phosphate or nano-alumina, with the content of nano-zinc phosphate or nano-alumina in the plating solution being 0.1~0.3 g / L, and the plating solution containing no complexing components.

[0013] Furthermore, element A is copper, and element B is zinc.

[0014] Secondly, the present invention provides a steel cord, which is obtained by drawing and twisting the novel structured coated steel wire described in any one of the first aspects.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention provides a novel structured coated steel wire and steel cord. By designing the composition and adhesion depth of the reinforcing layer, stabilizing layer, and adhesive layer, the corrosion resistance of the steel wire is improved. At the same time, the combination of steel wire and rubber also has better resistance to external erosion. The combination of steel wire and rubber not only has good initial bonding force, but also has a better corrosion bonding retention rate. Furthermore, the steel wire has better tensile and twisting properties in subsequent use. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the novel coated steel wire provided by the present invention; Figure 2 This is a copper-zinc distribution diagram of the 1.35mm coated steel wire provided by the present invention; Figure 3 This is a copper-zinc distribution diagram of a 1.35mm steel wire coated using a conventional thermal diffusion process, provided by the present invention. Figure 4 This is a schematic diagram comparing the corrosion resistance of two types of coated steel wires with a diameter of 1.35mm provided by the present invention; Figure 5 This is a comparative schematic diagram of the corrosion resistance of the F-structure cord provided by the present invention. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0018] like Figure 1 As shown, the novel structured coated steel wire includes a steel wire and a reinforcing layer, a stabilizing layer and an adhesive layer attached sequentially.

[0019] The tackifying layer, stabilizing layer, and reinforcing layer all contain copper and zinc. The tackifying layer is an alloy of copper and zinc, with a copper / zinc mass ratio of 1.778 ≤ copper / zinc ≤ 2.030. The stabilizing layer is composed of an alloy of copper and zinc or zinc itself, where, when the stabilizing layer is a copper-zinc alloy, the copper / zinc mass ratio is < 1. The reinforcing layer is an alloy of copper and zinc, with a copper / zinc mass ratio of 1.564 ≤ copper / zinc ≤ 1.740. The overall adhesion depth of the steel wire coating on the substrate is 0.8 μm ≤ d ≤ 4.0 μm. The adhesion depths of the tackifying, stabilizing, and reinforcing layers satisfy the following order: tackifying layer > reinforcing layer > stabilizing layer, with the tackifying layer's adhesion depth greater than half the total coating adhesion depth, and the stabilizing layer's adhesion depth less than one-third of the reinforcing layer's. The copper-zinc mass ratio and adhesion depth of the tackifying layer effectively ensure the initial bonding strength between the steel wire and the rubber, and facilitate subsequent drawing and twisting. The stabilizing layer, primarily composed of zinc with a minimal adhesion depth, enhances the corrosion resistance of the steel wire while ensuring effective bonding with the rubber. It also prevents excessive vulcanization between the steel wire and rubber. The copper-zinc ratio of the reinforcing layer is lower than that of the tackifying layer but greater than that of the stabilizing layer, and the adhesion depth is similar. This ensures sufficient vulcanization during the aging process after the steel wire and rubber bond, preventing a rapid decrease in bond strength during use and guaranteeing the stability of the steel wire products in subsequent applications.

[0020] When the stabilizing layer of the steel wire coating is a copper-zinc alloy, the steel wire coating is carried out using a single-metal-level plating method, that is, copper, zinc, and copper are plated sequentially on the steel wire substrate, and then thermally heated to form a three-phase alloy layer. Among the inner layer copper adjacent to the substrate and the outer layer copper, the inner layer copper is less than the outer layer copper. When the stabilizing layer of the steel wire coating is zinc, the adhesion-enhancing layer and the strengthening layer of the coating are obtained by co-plating copper and zinc to obtain an alloy layer of the two. Whether the stabilizing layer is a copper-zinc alloy or zinc, the plating solution for obtaining the zinc layer contains nano zinc phosphate or nano alumina. Nano zinc phosphate or nano alumina refers to nanoparticles treated with an aqueous superdispersant. The content of nano zinc phosphate or nano alumina in the plating solution is 0.1~0.3g / L, and there are no complexing components in the plating solution for obtaining the zinc layer. Nano-zinc phosphate and nano-alumina exhibit excellent stability and corrosion resistance. Their small particle size and large specific surface area result in high surface activity and strong adsorption capacity in plating solutions, allowing them to adsorb onto the cathode surface. Furthermore, due to their small particle size, they are easily encapsulated by zinc ions during electrodeposition, thus being deposited onto the substrate along with the zinc. Nano-zinc phosphate or nano-alumina can fill the micropores in the coating, reducing porosity and defects, and minimizing the penetration paths of corrosive media such as gases and liquids. This reduces the channels for corrosive media to enter the coating, thereby improving its corrosion resistance.

[0021] Example 1

[0022] This embodiment provides a method such as Figure 1The novel structured coated steel wire shown includes a steel wire and a reinforcing layer, a stabilizing layer, and an adhesion-enhancing layer attached sequentially. It is prepared through the following process: 1.35mm surface-cleaned steel wire → adhesion-enhancing layer electroplating → water washing → stabilizing layer electroplating → water washing → reinforcing layer electroplating → water washing → soaping → winding.

[0023] The adhesion-enhancing layer plating bath includes polymeric potassium thiocyanate at a concentration of 230 g / L (in other embodiments, it can be any value within the range of 226~260 g / L), Cu + The concentration is 25 g / L (in other examples, it can be any value in the range of 24.07~25.54 g / L), Zn 2+ The concentration is 5.35 g / L (any value in the range of 5.02~5.69 g / L can be used in other embodiments), the pH is 11.75 (any value in the range of 11.65~11.86 can be used in other embodiments), the plating bath temperature is 46℃ (any value in the range of 45~48℃ can be used in other embodiments), and the anode is H65 brass particles.

[0024] The stabilizing layer plating bath includes zinc sulfate with a concentration of 200 g / L (any value in the range of 180~220 g / L in other embodiments) and nano zinc phosphate with a concentration of 0.2 g / L (any value in the range of 0.1~0.3 g / L in other embodiments), pH 1.6 (any value in the range of 1.5~1.8 in other embodiments), at room temperature, and the nano zinc sulfate is nanoparticles treated with an aqueous superdispersant.

[0025] The strengthening layer plating bath includes polymeric potassium thiocyanate at a concentration of 270 g / L (in other embodiments, it can be any value within the range of 260~294 g / L), Cu + The concentration is 24 g / L (in other examples, it can be any value in the range of 23.74~24.39 g / L), Zn 2+ The concentration is 6.4 g / L (any value in the range of 6.19~6.52 g / L in other embodiments), the pH is 11.8 (any value in the range of 11.60~11.97 in other embodiments), the plating bath temperature is 36℃ (any value in the range of 35~38℃ in other embodiments), and the anode is H62 brass particles.

[0026] For the obtained 1.35mm coated steel wire, Figure 2 This is a copper-zinc distribution diagram of the 1.35mm coated steel wire of the present invention. The tackifying layer is 1.0μm thick, containing 66.2% copper and 33.8% zinc. The stabilizing layer is a 0.12μm zinc layer. The reinforcing layer is 0.68μm thick, containing 62.5% copper and 37.5% zinc.

[0027] Comparative Example 1 This comparative example uses an existing thermal diffusion process to prepare a 1.35mm brass-plated steel wire (plating thickness 1.82μm, copper content 65.8%, zinc content 34.2%).

[0028] Figure 3 The copper-zinc distribution diagram of the 1.35mm coated steel wire prepared by the existing thermal diffusion process shows that its structure is completely different from that of the coated steel wire prepared in Example 1.

[0029] The corrosion resistance of the coated steel wires prepared in Example 1 and Comparative Example 1 was compared. Both types of 1.35mm steel wires were sealed at both ends to prevent exposure of the steel wire substrate, which could affect the corrosion results. The two types of steel wires were placed in a 3.5% sodium chloride solution for 1 hour. After being removed, rinsed with cold water, and dried, the wires were observed under a stereomicroscope. The observation results are shown below. Figure 4 It was found that the coated steel wire prepared in Comparative Example 1 developed a series of rust spots on its surface after being immersed in salt solution, while the coated steel wire prepared in Example 1 only showed one slight rust spot on its surface after being immersed in salt solution, and the surface color still had the metallic luster of the coating, with almost no rust. It can be seen that the corrosion resistance of the coated steel wire prepared by the existing heat diffusion process is significantly improved.

[0030] Two types of 1.35mm steel wires were drawn using the same drawing process on the same wet drawing machine to obtain two types of 0.22mm monofilaments. As shown in Table 1, the drawing breakage length of the 1.35mm coated steel wire obtained in Example 1 was 2.8 million meters, while that of the 1.35mm steel wire obtained in Comparative Example 1 was 1.5 million meters. This demonstrates that the tensile properties of the coated steel wire obtained in Example 1 are superior to those of existing heat-diffusion process steel wires. The two types of 0.22mm monofilaments were then twisted into F-structure steel wire cords using the same twisting process on the same twisting machine. During twisting, the monofilaments corresponding to Example 1 broke 0.6 times per ton, while those corresponding to Comparative Example 1 broke 1.3 times per ton. This indicates that the coated steel wire of the present invention has superior twisting performance compared to traditional steel wires.

[0031] Table 1 - Performance Comparison of Steel Wires in Example 1 and Comparative Example 1

[0032] Corrosion resistance tests were conducted on identical lengths of both types of F-structure cords, with both ends of each cord sealed to prevent exposed steel wires from affecting corrosion. Both types of cords were immersed in a 3.5% sodium chloride solution for 35 minutes, then removed, rinsed with pure water, and dried in cold air. The surface condition of the cords was observed under a stereomicroscope, and the corrosion levels of the two types of cords were compared. Specific results are detailed below. Figure 5After being immersed in salt water, the conventional heat-diffusion coated cord (cord corresponding to Comparative Example 1) developed two rust spots on its surface, which then extended outwards. The rust was obvious and extensive, and yellow rust appeared around the rust spots, indicating corrosion of the base iron. This suggests that the corrosive medium had penetrated the coating and seeped into the base, causing corrosion. In contrast, after being immersed in salt water, the coated cord of this invention (cord corresponding to Example 1) showed only one minor rust spot on its surface, and the spot did not expand. No obvious yellow rust was observed around the rust spot. This demonstrates that the coating of this invention has a stronger resistance to corrosive media than the conventional heat-diffusion coating, and can better protect the base and mitigate the damage caused by corrosive media.

[0033] The cord of this invention is named FF, while the cord produced by the traditional thermal diffusion process is named RF. The bonding strength between the two cords and rubber was compared, including the adhesion retention after the cords and rubber were subjected to corrosive media for a certain period. The bonding and corrosion conditions for both cords and rubber were consistent. The bonding results of the two cords and rubber are shown in Table 2 below. The initial bonding force between the cord of this invention and rubber was 2042 N, while the bonding force between the traditional thermal diffusion cord and rubber was 1903 N. The bonding ability of the cord of this invention is significantly higher than that of the traditional thermal diffusion cord. Regarding the corrosion resistance after the two cords and rubber were bonded, the resulting rubber block was immersed in a 10% sodium chloride solution for 7 days, during which the immersion liquid level was kept below 2 / 3 of the depth of the rubber block. As shown in Table 2, after 7 days of salt water erosion, the bonding force between the cord of the present invention and the rubber after corrosion was 1571 N, while that of the traditional heat-diffusion cord was 1238 N, which was significantly lower than that of the cord of the present invention. Comparing the initial bonding forces of each cord with the rubber before corrosion, the bonding retention rate of the cord of the present invention with the rubber after corrosion was 76.9%, while that of the heat-diffusion cord was 65.1%. The cord of the present invention has better bonding force and retention rate with the rubber after corrosion than the heat-diffusion cord, indicating that the cord of the present invention not only has better self-corrosion resistance, but also has excellent resistance to corrosion after being bonded with rubber.

[0034] Table 2 - Performance Comparison of Cords in Example 1 and Comparative Example 1

[0035] In summary, compared with existing heat-diffusion brass wires, the coated structure steel wire of this invention has better corrosion resistance and better tensile and twisting properties for subsequent use. Moreover, its cord and rubber have better initial bonding force after bonding, and at the same time, it enhances the ability of the cord and rubber to resist the erosion of external corrosive media after bonding, thereby improving the retention rate of the cord and rubber bond after corrosion.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A novel structured coated steel wire, characterized in that, It includes steel wire and a reinforcing layer, a stabilizing layer and an adhesive layer attached in sequence; The adhesive layer is a first alloy containing element A and element B; The stabilizing layer is a substance containing only element B; The strengthening layer is a third alloy containing element A and element B; The adhesion depth of the tackifying layer is a, the adhesion depth of the stabilizing layer is b, the adhesion depth of the reinforcing layer is c, and the total adhesion depth of all coatings is d. The adhesion depth of each coating satisfies the following conditions: a+b+c=d, a>c>b, b+c<a, a / d>1 / 2, b / c<1 / 3. When the stabilizing layer is a substance containing only element B, the tackifying layer and the reinforcing layer are attached by co-plating elements A and B. Element A is copper, and element B is zinc.

2. The novel structured coated steel wire according to claim 1, characterized in that, The mass ratio of element A to element B in the first alloy is x, and satisfies the following condition: 1.778≤x≤2.

030.

3. The novel structured coated steel wire according to claim 1, characterized in that, The mass ratio of element A to element B in the third alloy is z, and satisfies the following condition: 1.564≤z≤1.

740.

4. The novel structured coated steel wire according to claim 1, characterized in that, The total adhesion depth satisfies the following condition: 0.8μm≤d≤4.0μm.

5. A steel cord, characterized in that, The novel structural coated steel wire according to any one of claims 1 to 4 is obtained by drawing and twisting.

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