Process for producing tire bead wire by using 70 # steel wire rod

Abstract

The invention discloses a process for producing a tire bead wire by using a 70 # steel wire rod, the 70 # steel wire rod is used as a raw material, and the 70 # steel wire rod comprises the following components in percentage by mass: 0.70-0.72% of C, 0.20-0.22% of Si, 0.50-0.55% of Mn, less than or equal to 0.015% of P, less than or equal to 0.015% of S, less than or equal to 0.03% of Cr, less than or equal to 0.03% of Ni, less than or equal to 0.04% of Cu and the balance of Fe and inevitable impurities. The 70 # steel wire rod is used for replacing commonly-used 77A and C72DA tire bead grade wire rods, the application grade and cost of wire rod raw materials are reduced, the content of manganese and silicon elements is increased, the hardness and hardenability of the steel wire are enhanced, and the hot working performance of the steel wire is improved; meanwhile, the organization structure of the steel wire material is innovatively improved through the tempering process, it is guaranteed that the steel wire rod with the low application grade obtains high strength and toughness, and the key indexes such as the breaking force, the yield ratio and torsion of the steel wire rod are improved. While the strength requirement of the automobile tire is met, the process difficulty of raw material production is reduced, the energy consumption is saved from the source, and the emission of three wastes is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of tire bead wire production, and in particular to a process for using 70# steel wire rod to produce tire bead wire. Background Art

[0002] Bead wire is an important skeleton material for radial tires. It is used to enhance the performance of the tire bead and to fix the tire body tightly on the rim. With the implementation of the strategic goal of developing new energy vehicles, energy saving, low carbon, low energy consumption and low pollution will become the only way for the development of the tire industry. Bead wires with higher strength and higher fatigue resistance can broaden the use scenarios of tires and increase their service life, and ultimately achieve the goals of deepening energy conservation and emission reduction, leading the green automobile tire industry, and promoting the development of new energy vehicles. In recent years, competition in the tire manufacturing industry has become increasingly fierce, and the production of lighter and less fuel-consuming tires has placed more stringent requirements on the strength and toughness of bead wires. The extrusion and friction that the tire is subjected to during driving are reflected at the bead wire level, which can be quantified by indicators such as stretching, compression, and torsion. The physical properties of tire bead wire mainly depend on the composition of the raw material wire rod and the effect of the tempering process. At present, the industry's production equipment and processes tend to be stable. From the perspective of economy and production stability, it is difficult to improve the tempering process. High-carbon content tire bead grade special wire rods are generally used to make up for the shortcomings of the tempering process, which greatly increases the raw material cost and the emission of three wastes, which is not conducive to industry progress and environmental protection development requirements. Summary of the invention

[0003] The purpose of the present invention is to provide a process for producing tire bead wire using 70# steel wire rod, using 70# steel wire rod to replace the commonly used 77A and C72DA tire bead grade wire rod, reducing the application grade and cost of the wire rod raw material, increasing the content of manganese and silicon elements, strengthening the hardness and hardenability of the steel wire, and improving its hot working performance; at the same time, the organizational structure of the steel wire material is improved through the innovation of the tempering process, ensuring the stability of the internal grain size, ensuring that the wire rod with a lower application grade also obtains higher strength and toughness, improving its breaking force, yield strength ratio, torsion and other key indicators, and achieving the goal of saving production costs and improving quality. While meeting the strength requirements of automobile tires, it reduces the process difficulty of raw material production, saves energy consumption from the source, and reduces the emission of three wastes, so as to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions: 70# steel wire rod is used as raw material, and the composition of the wire rod is calculated by mass percentage, including: C: 0.70%-0.72%, Si: 0.20%-0.22%, Mn: 0.50%-0.55%, P: ≤0.015%, S: ≤0.015%, Cr: ≤0.03%, Ni: ≤0.03%, Cu: ≤0.04%, and the balance is Fe and unavoidable impurities; specifically, the following steps are included: Step 1: Dephosphorize, clean, boron coat, draw, and wind the Φ5.5mm 70# steel wire rod in sequence, wherein the drawing process requires 3 to 5 passes through the die to obtain a large drawn steel wire semi-finished product.

[0005] Step 2: After welding and grinding the large-drawn steel wire obtained above, a multi-pass multi-servo direct-drive wire drawing machine is used to draw the wire through a die for 6 to 7 passes to obtain a medium-drawn semi-finished steel wire.

[0006] Step 3: Degrease, pickle, and alkaline wash the intermediate drawn steel wire to remove surface impurities, and heat the steel wire by variable frequency induction current to eliminate internal stress. After tempering, cool it with circulating water. The tempering temperature is controlled at 400-500°C, the water cooling temperature is 20-80°C, and the wire-winding speed is 200-400m / min.

[0007] Step 4: After cleaning, immerse the steel wire in a copper plating solution. After an oxidation-reduction reaction, the Cu in the solution 2+ Sn 2+ The surface Fe is oxidized, the bath temperature is controlled at 35±5℃, and the Cu 2+ Sn 2+ The concentrations are 3.0-9.0 g / l and 0.1-0.3 g / l, respectively, and the bronze alloy layer is diffused to obtain a copper content of 98.35 ± 1.35% and a tin content of 1.65 ± 1.35% in the coating. After rinsing and drying, the steel wire is passed through a cotton thread soaked in the Kumar solution to coat the Kumar resin.

[0008] Step 5: The finished tire bead wire is taken up through an I-shaped wheel and tested for breaking force, yield strength ratio and torsional performance.

[0009] Step 6: Classify and package qualified products according to different varieties and specifications for storage.

[0010] Beneficial effects of the present invention: The 70# steel wire rod of the present invention is used in the process of producing tire bead wire. The 70# steel wire rod is used as a raw material in the production of the tire bead wire, thereby reducing costs while meeting customer needs: compared with tire bead grade special wire rods (77A, C72DA), the 70# steel wire rod has lower costs, increases the content of manganese and silicon elements, and enhances the heat treatment performance of the tire bead wire.

[0011] The 70# steel wire rod of the present invention is used in the process of producing tire bead wire, and the performance of tire bead wire is improved by improving the processes such as drawing, chemical plating and tempering: the drawing pass varies with the product specifications, and the temperature of the plating solution in the chemical plating process varies with Cu 2+ / Sn 2+ The concentration is changed, and the key coefficients such as heating temperature, cooling water temperature, and wire speed in the tempering process are adjusted to match each other. The drawing resistance is reduced, the diffusion efficiency of the coating is improved, the internal stress of the steel is eliminated, the toughness is enhanced, and the heat treatment efficiency is improved, so as to achieve the goal of saving energy consumption and improving product strength and toughness.

[0012] The 70# steel wire rod of the present invention is used in the process of producing tire bead wire. The wire rod essentially uses a No. 1 steel grade wire rod instead of a special wire rod for the tire bead grade, which not only simplifies the wire rod raw material production process of the tire bead wire and saves production costs, but also obtains the heat treatment conditions under the best performance consumption of steel by improving the key tempering parameters (heating temperature, cooling water temperature, and wire-winding speed), thereby improving the strength and toughness of the steel. In addition, as the content of manganese and silicon elements increases, the stability of the grain size during the tempering process of the material is guaranteed; manganese and sulfur in the steel form MnS with a higher melting point, which avoids the formation of FeS film on the grain boundary, eliminates the hot brittleness of the steel, and improves the hot processing performance. Under the premise of reducing the raw material and production and processing costs, the important physical properties of the tire bead wire, such as the breaking force, yield strength ratio, and torsion value, are improved. The wide application of 70# steel wire rod in tire bead wire has been achieved, making an important contribution to the low-carbon and energy-saving production of the tire industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The figure is a comparison chart of the breaking force of the tire bead wire products obtained according to Examples 1, 2, and 3 of the present invention and the original process.

[0014] Figure 2 The figure is a comparison chart of the yield strength ratio of the tire bead wire products obtained according to Examples 1, 2, and 3 of the present invention and the original process.

[0015] Figure 3 The figure is a comparison chart of the torsion value of the tire bead wire product obtained according to Examples 1, 2, and 3 of the present invention and the original process. DETAILED DESCRIPTION

[0016] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments.

[0017] Example 1: In this example, Φ5.5mm 70# steel wire rod is used as raw material, and the composition of the wire rod, in mass percentage, includes: C: 0.70%, Si: 0.20%, Mn: 0.50%, P: 0.013%, S: 0.008%, Cr: 0.02%, Ni: 0.01%, Cu: 0.002%, and the remainder is Fe and unavoidable impurities.

[0018] (1) The wire rod is passed through a descaling machine to remove the surface oxide scale, and then subjected to surface cleaning, boron coating, drawing, and wire winding processes in sequence. The drawing process requires five passes of the die to obtain a Φ3.13 mm large drawn steel wire; (2) After the large-drawn semi-finished product is welded and polished, it is drawn through 7 passes of a die using a multi-pass multi-servo direct-drive wire drawing machine to obtain a Φ1.60 mm medium-drawn steel wire semi-finished product; (3) Degrease, pickle, and alkaline wash the above-mentioned intermediate drawn steel wire in turn to remove surface impurities, and temper the steel wire by variable frequency induction current to eliminate internal stress. After tempering, cool it with circulating water. Set the tempering temperature to 425°C, the circulating cooling water temperature to 30°C, and the wire take-up speed to 260m / min; (4) After cleaning, immerse the steel wire in a copper plating solution. After an oxidation-reduction reaction, the Cu in the solution 2+ Sn 2+ The surface Fe is oxidized, the bath temperature is 30°C, and the Cu content in the bath is 2+ Sn 2+ The concentrations were 4.5 g / l and 0.2 g / l, respectively, and the bronze alloy layer was diffused. After rinsing and drying, the steel wire was passed through a cotton thread soaked in the Kumar solution to coat the Kumar resin; (5) The finished bead wire is taken up by a Z54-type I-shaped wheel and tested for breaking force, yield strength ratio, total elongation at break, and torsional performance; (6) Qualified products will be packaged and stored according to different varieties and specifications.

[0019] The 1.60mmNT tire bead steel wire obtained in this embodiment has a copper content of 97.79% and a tin content of 2.21% and a breaking force of 3990N, which is 5.78% higher than the original process; the yield strength ratio is 95.4%, which is 7.46% higher than the original process; and the torsion value is 35, which is 52.17% higher than the original process.

[0020] Example 2: In this example, Φ5.5mm 70# steel wire rod is used as raw material, and the composition of the wire rod, in mass percentage, includes: C: 0.70%, Si: 0.21%, Mn: 0.52%, P: 0.015%, S: 0.014%, Cr: 0.01%, Ni: ≤0.03%, Cu: ≤0.004%, and the remainder is Fe and unavoidable impurities.

[0021] (1) The wire rod is passed through a descaling machine to remove the surface oxide scale, and then the surface cleaning, boron coating, drawing, and wire winding processes are carried out in sequence. The drawing process requires four passes of the die to obtain a Φ3.06 mm large drawn steel wire; (2) After the large-drawn semi-finished product is welded and polished, it is drawn through 6 passes of a die using a multi-pass multi-servo direct-drive wire drawing machine to obtain a Φ1.65 mm medium-drawn steel wire semi-finished product; (3) Degrease, pickle, and alkaline wash the above-mentioned intermediate drawn steel wire in turn to remove surface impurities, and temper the steel wire by variable frequency induction current to eliminate internal stress. After tempering, cool it with circulating water. Set the tempering temperature to 455°C, the circulating cooling water temperature to 50°C, and the wire take-up speed to 310m / min; (4) After cleaning, immerse the steel wire in a copper plating solution. After an oxidation-reduction reaction, the Cu in the solution 2+ Sn 2+ The surface Fe is oxidized, the bath temperature is 40°C, and the Cu 2+ Sn 2+ The concentrations were 7.5 g / l and 0.3 g / l, respectively, and the bronze alloy layer was diffused. After rinsing and drying, the steel wire was passed through a cotton thread soaked in the Kumar solution to coat the Kumar resin; (5) The finished bead wire is taken up by a Z54-type I-shaped wheel and tested for breaking force, yield strength ratio, total elongation at break, and torsional performance; (6) Qualified products will be packaged and stored according to different varieties and specifications.

[0022] The 1.65mmNT bead wire obtained in this embodiment has a product bow height of 18mm / 75cm, a vector warp of 0mm / 3m, a coating copper content of 98.08%, and a tin content of 1.92%. The breaking force is 4290N, which is 5.12% higher than that of the original process; the yield strength ratio is 95.9%, which is 10.05% higher than that of the original process; and the torsion value is 32, which is 45.45% higher than that of the original process.

[0023] Embodiment 3: This embodiment uses Φ5.5mm 70# steel wire rod as raw material, and the composition of the wire rod is calculated by mass percentage, including: C: 0.70%, Si: 0.22%, Mn: 0.55%, P: 0.015%, S: 0.014%, Cr: 0.01%, Ni: ≤0.03%, Cu: ≤0.004%, and the balance is Fe and unavoidable impurities; (1) The wire rod is passed through a descaling machine to remove the surface oxide scale, and then the surface cleaning, boron coating, drawing, and wire winding processes are carried out in sequence. The drawing process requires 5 passes of the die to obtain a Φ3.25 mm large drawn steel wire; (2) After the large-drawn semi-finished product is welded and polished, it is drawn through 6 passes of a die using a multi-pass multi-servo direct-drive wire drawing machine to obtain a Φ2.00 mm medium-drawn steel wire semi-finished product; (3) Degrease, pickle, and alkaline wash the above-mentioned intermediate drawn steel wire in turn to remove surface impurities, and temper the steel wire by variable frequency induction current to eliminate internal stress. After tempering, cool it with circulating water. Set the tempering temperature to 475°C, the circulating cooling water temperature to 70°C, and the wire take-up speed to 360m / min; (4) After cleaning, immerse the steel wire in a copper plating solution. After an oxidation-reduction reaction, the Cu in the solution 2+ Sn 2+ The surface Fe is oxidized, the bath temperature is 35°C, and the Cu 2+ Sn 2+ The concentrations were 6.5 g / l and 0.2 g / l, respectively, and the bronze alloy layer was diffused. After rinsing and drying, the steel wire was passed through a cotton thread soaked in the Kumar solution to coat the Kumar resin; (5) The finished bead wire is taken up by a Z54-type I-shaped wheel and tested for breaking force, yield strength ratio, total elongation at break, and torsional performance; (6) Qualified products will be packaged and stored according to different varieties and specifications.

[0024] The 2.00mm NT bead wire obtained in this embodiment has a copper content of 98.35% and a tin content of 1.65%. The breaking force is 5673N, which is 3.81% higher than that of the original process; the yield strength ratio is 95.2%, which is 7.87% higher than that of the original process; and the torsion value is 27, which is 42.11% higher than that of the original process.

[0025] Combining the above three tire bead wire embodiments of 1.60mmNT, 1.65mmNT and 2.00mmNT, it can be seen that the method of the present invention not only reduces the production cost of the product by applying the lower grade 70# steel plate, but also improves the breaking force, yield strength ratio, torsion value and other key physical properties of the steel wire, while meeting the customer's needs. Figure 1 , 2 As shown in 3, the product quality is significantly improved, the product application range is further broadened, and the production cost is reduced.

[0026] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for producing tire bead wire using 70# steel wire rod, characterized in that: 70# steel wire rod is used as raw material, and the composition of the wire rod is calculated by mass percentage, including: C: 0.70%-0.72%, Si: 0.20%-0.22%, Mn: 0.50%-0.55%, P: ≤0.015%, S: ≤0.015%, Cr: ≤0.03%, Ni: ≤0.03%, Cu: ≤0.04%, and the balance is Fe and unavoidable impurities; The specific steps include: Step 1, dephosphorizing, surface cleaning, boron coating, drawing, and winding the 70# steel wire rod in sequence to obtain a semi-finished large drawn steel wire; Step 2, welding and grinding the large drawn steel wire obtained above, and then drawing it through multiple passes to obtain a medium drawn semi-finished steel wire; Step 3, degreasing, pickling and alkali washing the intermediate drawn steel wire to remove surface impurities, tempering and heating the steel wire by variable frequency induction current to eliminate internal stress, and cooling by circulating water after tempering; controlling the tempering temperature at 400-500°C, the water cooling temperature at 20-80°C, and the wire taking-up speed at 200-400m / min; Step 4: After cleaning, immerse the steel wire in a copper plating solution. After an oxidation-reduction reaction, the Cu in the solution 2+ Sn 2+ The surface Fe is oxidized and diffused to form a bronze alloy layer; after rinsing and drying, the steel wire is passed through a cotton thread soaked in Kumar solution to be coated with Kumar resin; Step 5, the finished bead wire is taken up by an I-shaped wheel, and the breaking force, yield strength ratio and torsional performance are tested; Step 6: Classify and package qualified products according to different varieties and specifications for storage.

2. A process for producing tire bead wire using 70# steel wire rod as claimed in claim 1, characterized in that: In step 1, the drawing process needs to go through 3 to 5 passes of the die.

3. The process for producing tire bead wire using 70# steel wire rod as claimed in claim 1, characterized in that: In step 2, the drawing process uses a multi-servo direct-drive wire drawing machine and draws through 6 to 7 passes of the die.

4. The process for producing tire bead wire using 70# steel wire rod as claimed in claim 1, characterized in that: In step 4, the plating solution temperature is controlled at 35±5°C, and the Cu 2+ Sn 2+ The concentrations are 3.0-9.0 g / l and 0.1-0.3 g / l respectively.

5. The process for producing tire bead wire using 70# steel wire rod as claimed in claim 1, characterized in that: In step 4, the copper content in the coating is 98.35±1.35%, and the tin content is 1.65±1.35%.

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