Application of an electric furnace wire rod in steel cord production

Abstract

The present invention discloses an application of an electric furnace wire rod in the production of steel cords, comprising: (1) rough drawing and medium drawing of the electric furnace wire rod to obtain medium-drawn steel wire with a diameter of 1.15 mm to 2.20 mm; (2) quenching the medium-drawn steel wire by AQ liquid; (3) pickling, brass plating, and galvanizing the medium-drawn steel wire, and then subjecting the medium-drawn steel wire to MF diffusion, so that copper and zinc atoms diffuse mutually to form a brass alloy layer, and the copper content in the plating layer is 63.5±2.5%; (4) drawing the obtained brass-plated steel wire by a wet drawing method to a single wire with a diameter of 0.18 to 0.38 mm for application in the production of steel cords. It can not only replace 72C and 82C steel grades, but also solve the problem of high wire breakage rate caused by increasing the diameter of 72Cr brass-plated steel wire to meet customer needs. That is, by reducing the diameter of the brass-plated steel wire, the wire breakage rate is reduced and the yield rate is improved while ensuring that the breaking tensile force meets customer needs. At the same time, the extensive use of EAF82C electric furnace wire rod can reduce the switching of different wire rod grades and reduce production complexity.

Description

Technical Field

[0001] The invention relates to a raw material processing technology for steel cords, and in particular to an application of an electric furnace wire rod in the production of steel cords. Background Art

[0002] With the establishment and implementation of my country's "dual carbon" strategy, green and sustainable development plays a core supporting role in the realization of the "dual carbon" goals. Green and sustainability are the inevitable trend of the development of automobile tires. From the country to the public, more and more attention is paid to sustainable development, and the requirements for materials used in tire production are also getting higher and higher. The weight of steel cord in tires accounts for about 15%. On the premise of ensuring that the performance meets customer standards, the application of sustainable raw materials in steel cord production makes an important contribution to the sustainable development of green tires.

[0003] The steel grades used for steel cord are mainly 72C, 72Cr, and 82C. In order to reduce the cost of raw materials, the industry has tried to use 72Cr instead of 82C, or even 72C instead of 82C to produce some steel cord specifications. However, the switching of different wire rod grades is prone to large differences in torsion and aging torsion parameters. If they are not distinguished or mixed in time, it is easy to cause customers to frequently have warping and bending problems during calendering and cutting. In addition, some finished cord products are prone to the problem of the breaking tensile force not meeting customer requirements due to the replacement of 82C with 72Cr. Although customer needs can be met by increasing the diameter of the brass-plated steel wire, the cord wire breakage increases, affecting the yield rate; in addition, the application of multiple brands of wire rods also brings management and production complexity issues. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention proposes an application of an electric furnace wire rod in the production of steel cords. The electric furnace wire rod is used as a raw material, which can not only replace 72C and 82C steel grades, but also solve the problem of high wire breakage rate caused by increasing the diameter of 72Cr brass-plated steel wire to meet customer needs. That is, by reducing the diameter of the brass-plated steel wire, the wire breakage rate is reduced and the yield rate is improved while ensuring that the breaking tensile force meets customer needs. At the same time, the large-scale use of EAF82C electric furnace wire rods can reduce the switching of different wire rod grades and reduce production complexity.

[0005] The technical solution adopted by the present invention is: an application of electric furnace wire rod in the production of steel cord, comprising:

[0006] (1) The electric furnace wire rod is rough-drawn and medium-drawn to obtain medium-drawn steel wire with a diameter of 1.15 mm to 2.20 mm;

[0007] (2) The intermediate drawn steel wire is quenched by AQ liquid;

[0008] (3) The medium-drawn steel wire is pickled, brass-plated, and galvanized, and then diffused by MF to allow copper and zinc atoms to diffuse into each other to form a brass alloy layer. The copper content in the coating is 63.5±2.5%;

[0009] (4) The brass-plated steel wire is drawn into a single wire with a diameter of 0.18-0.38 mm by a wet drawing method and used in the production of steel cord.

[0010] Based on the above solution, as a preferred embodiment, the electric furnace wire rod model is EAF82C, with a diameter of 5.5 mm.

[0011] Based on the above solution, as a preferred alternative, the application of 72C in the 2+2x0.35 HT specification includes:

[0012] (1) Mechanically descaling the surface of the electric furnace wire rod, then pickling, water washing, boron coating, and drawing in sequence, roughly drawing the electric furnace wire rod to Φ3.25 mm, and then collecting it on the wire take-up rack;

[0013] (2) Pull the thick drawn wire on the take-up rack to the wire drawing machine, and draw the medium drawn wire to Φ1.90mm;

[0014] (3) The medium-drawn steel wire is sequentially subjected to degreasing, heating furnace, AQ quenching, water cooling, pickling, water washing, copper plating, water washing, galvanizing, water washing, hot water washing, MF medium frequency diffusion, water cooling, phosphoric acid immersion, water washing, soap immersion, and finally collected on a large I-shaped wheel to obtain a Φ1.90 mm brass-plated steel wire with a brass coating on the surface of the steel wire and a copper content of 63.5±2.5% in the coating;

[0015] (4) The steel wire is drawn to 0.35 mm through a multi-pass die, and the diameter of the wet-drawn single wire is 0.35 ± 0.05 mm;

[0016] (5) The wet-drawn monofilaments are used for steel cords with specifications of 2+2x0.35 HT, with 2 Φ0.35 mm monofilaments as core wires and 2 Φ0.35 mm monofilaments as outer layers. The desired finished product 2+2x0.35 HT steel cord is obtained by double twisting.

[0017] Based on the above solution, as a preferred alternative, the application of 72Cr in 3+8x0.33 ST specifications includes:

[0018] (1) Mechanically descaling the surface of the electric furnace wire rod, then pickling, water washing, boron coating, and drawing in sequence, roughly drawing the electric furnace wire rod to Φ3.25 mm, and then collecting it on the wire take-up rack;

[0019] (2) Pull the thick drawn wire on the take-up rack to the wire drawing machine, and draw the medium drawn wire to Φ2.05mm;

[0020] (3) The medium-drawn steel wire is sequentially subjected to degreasing, heating furnace, AQ quenching, water cooling, pickling, water washing, copper plating, water washing, galvanizing, water washing, hot water washing, MF medium frequency diffusion, water cooling, phosphoric acid immersion, water washing, soap immersion, and finally collected on a large I-shaped wheel to obtain a Φ2.05 mm brass-plated steel wire with a brass coating on the surface of the steel wire and a copper content of 63.5±2.5% in the coating;

[0021] (4) The steel wire is drawn to 0.33 mm through a multi-pass die, and the diameter of the wet-drawn single wire is 0.33 ± 0.05 mm;

[0022] (5) The wet-drawn monofilaments are used for 3+8x0.33 ST steel cords, with 3 Φ0.33 mm monofilaments as the core wires and 8 Φ0.33 mm monofilaments as the outer layer. The desired finished 3+8x0.33 ST steel cords are obtained by double twisting.

[0023] Based on the above solution, as a preferred alternative, the application of 72Cr in 2x0.30 ST specification includes:

[0024] (1) Mechanically descaling the surface of the electric furnace wire rod, then pickling, water washing, boron coating, and drawing in sequence, roughly drawing the electric furnace wire rod to Φ3.25 mm, and then collecting it on the wire take-up rack;

[0025] (2) Pull the thick drawn wire on the take-up rack to the wire drawing machine, and draw the medium drawn wire to Φ1.90mm;

[0026] (3) The medium-drawn steel wire is sequentially subjected to degreasing, heating furnace, AQ quenching, water cooling, pickling, water washing, copper plating, water washing, galvanizing, water washing, hot water washing, MF medium frequency diffusion, water cooling, phosphoric acid immersion, water washing, soap immersion, and finally collected on a large I-shaped wheel to obtain a Φ1.90 mm brass-plated steel wire with a brass coating on the surface of the steel wire and a copper content of 63.5±2.5% in the coating;

[0027] (4) The steel wire is drawn to 0.30 mm through a multi-pass die, and the diameter of the wet-drawn single wire is 0.30 ± 0.05 mm;

[0028] (5) The wet-drawn monofilament is used for the steel cord of 2x0.30 ST specification. Two Φ0.30 mm monofilaments are double-twisted to produce the required finished product 2x0.30 ST steel cord.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] Using electric furnace wire rod as raw material, the compression ratio is reduced by reducing the diameter of the brass-plated steel wire, thereby reducing the broken wire rate of the finished cord, effectively improving the yield rate and contributing to sustainable development.

[0031] The trace elements in the electric furnace wire rod can improve the microstructure and mechanical properties of the brass-plated steel wire during the alloying process, and increase the plasticity and tensile strength of the brass-plated steel wire.

[0032] On the premise of ensuring the carbon content, the compression ratio is reduced by reducing the diameter of the brass-plated steel wire. This can not only make the breaking tensile force of the steel cord meet customer requirements, but also reduce the wire breakage rate in the entire steel cord production process and improve the yield rate, making an important contribution to the sustainable development of green tires. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a comparison chart of the compression ratio of the brass-plated steel wire obtained in Examples 1, 2, and 3 of the present invention in the wet drawing process and the original process;

[0034] Figure 2 It is a comparison chart of the broken wire rate of the steel cord obtained in the plying process of the invention embodiments 1, 2 and 3 and the original material. DETAILED DESCRIPTION

[0035] The present invention will be further described below by way of examples, but the scope of the present invention is not limited thereto.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0037] An application of an electric furnace wire rod in the production of a steel cord specifically comprises the following steps:

[0038] (1) Electric furnace wire rod is used as raw material, and the composition of the wire rod is calculated by mass percentage, including: C: 0.82%, Si: 0.21%, Mn: 0.53%, P: 0.011%, S: 0.004%, Cr: 0.04%, Cu: 0.01%, Al: 0.002%, and the balance is Fe and unavoidable impurities;

[0039] (2) rough drawing and intermediate drawing of the electric furnace wire rod to obtain intermediate drawn steel wire with a diameter of 1.15 mm to 2.20 mm;

[0040] (3) The intermediate drawn steel wire obtained above is quenched by AQ liquid to form a microstructure of troostite and a small amount of coarse lamellar pearlite.

[0041] (4) The medium drawn steel wire is pickled and brass plated, and then diffused by MF to allow copper and zinc atoms to diffuse into each other to form a brass alloy layer. The copper content in the coating is 63.5±2.5%;

[0042] (5) drawing the obtained brass-plated steel wire into a single wire with a diameter of 0.18-0.38 mm by a wet drawing method;

[0043] (6) The obtained monofilament with a diameter of 0.18-0.38 mm is paralleled, cord-formed and outer-wound through various double twisting machines and outer-winding machines according to certain structure, arrangement and twisting requirements;

[0044] (7) Steel cords that have passed the inspection must be classified according to different varieties and specifications and packaged by batches.

[0045] Example 1: Application of EAF82C electric furnace wire rod to replace 72C (5.5mm) in 2+2x0.35 HT specification, specifically including the following steps:

[0046] (1) Electric furnace wire rod is used as raw material, and the composition of the wire rod is calculated by mass percentage, including: C: 0.82%, Si: 0.21%, Mn: 0.53%, P: 0.011%, S: 0.004%, Cr: 0.04%, Cu: 0.01%, Al: 0.002%, and the balance is Fe and unavoidable impurities;

[0047] (2) Mechanically descaling the surface of the electric furnace wire rod, then pickling, water washing, boron coating, and drawing in sequence, drawing the electric furnace wire rod to Φ3.25 mm, and then collecting it on the wire take-up rack;

[0048] (3) The process of the surface-treated electric furnace wire rod is optimized, and the diameter of the intermediate drawn steel wire is reduced to Φ1.90 mm;

[0049] (4) The above-mentioned intermediate drawing steel wire is sequentially subjected to degreasing, heating furnace, AQ quenching, water cooling, pickling, water washing, copper plating, water washing, galvanizing, water washing, hot water washing, MF intermediate frequency diffusion, water cooling, phosphoric acid immersion, water washing, soap immersion, and finally collected on a large I-shaped wheel to obtain a Φ1.90 mm brass-plated steel wire with a brass coating on the surface of the steel wire and a copper content of 63.5±2.5%;

[0050] (5) The steel wire is drawn to 0.35 mm by a wet drawing method through a multi-pass die, and the diameter of the wet drawn single wire is about 0.35 ± 0.05 mm;

[0051] (6) The wet-drawn monofilaments are used for 2+2x0.35 HT steel cords, with 2 Φ0.350 mm monofilaments as core wires and 2 Φ0.350 mm monofilaments as outer layers, and the desired finished 2+2x0.35 HT steel cords are obtained by double twisting.

[0052] (7) Steel cords that have passed the inspection must be packaged by batch;

[0053] Comparative Example:

[0054] In the application of 2+2x0.35 HT specification, 72C also adopts the above process, the difference is that the middle drawing is Φ2.10mm.

[0055] The process optimization and test results are as follows:

[0056]

[0057] The diameter of the brass-plated steel wire of the 2+2x0.35 HT steel cord obtained in this embodiment is reduced from 2.10 mm to 1.90 mm in the semi-finished process, a decrease of 9.5%. The wire breakage rate in the plying process is about 0.72 times / t, a decrease of 42% compared with the original process. The average breaking tensile force of the finished cord is 1065 N (standard ≥ 1025 N).

[0058] Example 2: Application of EAF82C electric furnace wire rod to replace 72Cr (5.5mm) in 3+8x0.33 ST specification, specifically including the following steps:

[0059] (1) Electric furnace wire rod is used as raw material, and the composition of the wire rod is calculated by mass percentage, including: C: 0.82%, Si: 0.21%, Mn: 0.53%, P: 0.011%, S: 0.004%, Cr: 0.04%, Cu: 0.01%, Al: 0.002%, and the balance is Fe and unavoidable impurities;

[0060] (2) Mechanically descaling the surface of the electric furnace wire rod, then pickling, water washing, boron coating, and drawing in sequence, drawing the electric furnace wire rod to Φ3.25 mm, and then collecting it on the wire take-up rack;

[0061] (3) The process of the surface-treated electric furnace wire rod is optimized, and the diameter of the intermediate drawn steel wire is reduced to Φ2.05 mm;

[0062] (4) The above-mentioned medium-drawn steel wire is sequentially subjected to degreasing, heating furnace, AQ quenching, water cooling, pickling, water washing, copper plating, water washing, galvanizing, water washing, hot water washing, MF medium frequency diffusion, water cooling, phosphoric acid immersion, water washing, soap immersion, and finally collected on a large I-shaped wheel to obtain a Φ2.05 mm brass-plated steel wire with a brass coating on the surface of the steel wire and a copper content of 63.5±2.5%.

[0063] (5) The steel wire is drawn to 0.33 mm by a wet drawing method through a multi-pass die, and the diameter of the wet drawn single wire is about 0.33 ± 0.05 mm;

[0064] (6) The wet-drawn monofilaments are used for 3+8x0.33 ST steel cords, with 3 Φ0.330 mm monofilaments as core wires and 8 Φ0.330 mm monofilaments as outer layers, and the desired finished product 3+8x0.33 ST steel cords are obtained by double twisting.

[0065] (7) Steel cords that have passed the inspection must be packaged by batch;

[0066] Comparative Example:

[0067] In the application of 72Cr in 3+8x0.33 ST specification, the above process is also adopted, the difference is the middle drawing Φ2.15mm.

[0068] The process optimization and test results are as follows:

[0069]

[0070] The diameter of the brass-plated steel wire of the 3+8x0.33 ST steel cord obtained in this embodiment was reduced from 2.15mm to 2.05mm in the semi-finished process, a decrease of 4.7%. The wire breakage rate during the plying process was about 0.46 times / t, a decrease of 58% compared with the original process. The average breaking tensile force of the finished cord was 3130 N (standard ≥ 2980 N).

[0071] Example 3: Application of EAF82C electric furnace wire rod to replace 72Cr (5.5mm) in 2x0.30 ST specification, specifically including the following steps:

[0072] (1) Electric furnace wire rod is used as raw material, and the composition of the wire rod is calculated by mass percentage, including: C: 0.82%, Si: 0.21%, Mn: 0.53%, P: 0.011%, S: 0.004%, Cr: 0.04%, Cu: 0.01%, Al: 0.002%, and the balance is Fe and unavoidable impurities;

[0073] (2) Mechanically descaling the surface of the electric furnace wire rod, then pickling, water washing, boron coating, and drawing in sequence, drawing the electric furnace wire rod to Φ3.25 mm, and then collecting it on the wire take-up rack;

[0074] (3) The process of the surface-treated electric furnace wire rod was optimized, and the diameter of the intermediate drawn steel wire was reduced from Φ1.97 mm to Φ1.90 mm;

[0075] (4) The above-mentioned intermediate drawing steel wire is sequentially subjected to degreasing, heating furnace, AQ quenching, water cooling, pickling, water washing, copper plating, water washing, galvanizing, water washing, hot water washing, MF intermediate frequency diffusion, water cooling, phosphoric acid immersion, water washing, soap immersion, and finally collected on a large I-shaped wheel to obtain a Φ1.90 mm brass-plated steel wire with a brass coating on the surface of the steel wire and a copper content of 63.5±2.5%;

[0076] (5) The steel wire is drawn to 0.30 mm by a wet drawing method through a multi-pass die, and the diameter of the wet drawn single wire is about 0.30 ± 0.05 mm;

[0077] (6) The wet-drawn monofilament is used for a steel cord with a specification of 2x0.30 ST, and two Φ0.300 mm monofilaments are double-twisted to produce the desired finished product 2x0.30 ST steel cord;

[0078] (7) Steel cords that have passed the inspection must be packaged by batch;

[0079] Comparative Example:

[0080] In the application of 2x0.30 ST specification, 72Cr also adopts the above process, the difference is the middle drawing Φ1.97mm.

[0081] The process optimization and test results are as follows:

[0082]

[0083] The diameter of the brass-plated steel wire of the 2x0.30 ST steel cord obtained in this embodiment was reduced from 1.97 mm to 1.90 mm in the semi-finished process, a decrease of 3.6%. The wire breakage rate during the plying process was about 1.11 times / t, a decrease of 62% compared with the original process. The average breaking tensile force of the finished cord was 465 N (standard ≥ 445 N).

[0084] Combining the above four embodiments, it can be seen that the method of the present invention reduces the compression ratio by reducing the diameter of the brass-plated steel wire while ensuring the carbon content, which not only reduces the broken wire rate of the finished cord, but also improves the yield rate, thus contributing to sustainable development.

[0085] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. An application of electric furnace wire rod in steel cord production, characterized in that: include: (1) The electric furnace wire rod is rough-drawn and medium-drawn to obtain medium-drawn steel wire with a diameter of 1.15 mm to 2.20 mm; (2) The intermediate drawn steel wire is quenched by AQ liquid; (3) The medium-drawn steel wire is pickled, brass-plated, and galvanized, and then diffused by MF to allow copper and zinc atoms to diffuse into each other to form a brass alloy layer. The copper content in the coating is 63.5±2.5%; (4) The brass-plated steel wire is drawn into a single wire with a diameter of 0.18-0.38 mm by a wet drawing method and used in the production of steel cord; The model of the electric furnace wire rod is EAF82C, with a diameter of 5.5 mm. The composition of the electric furnace wire rod is expressed in mass percentage, including: C: 0.82%, Si: 0.21%, Mn: 0.53%, P: 0.011%, S: 0.004%, Cr: 0.04%, Cu: 0.01%, Al: 0.002%, and the balance is Fe and inevitable impurities.

2. The use of the electric furnace wire rod in the production of steel cord according to claim 1, characterized in that: Replace 72C in 2+2x0.35 HT specification applications, including: (1) Mechanically descaling the surface of the electric furnace wire rod, then pickling, water washing, boron coating, and drawing in sequence, roughly drawing the electric furnace wire rod to Φ3.25 mm, and then collecting it on the wire take-up rack; (2) Pull the thick drawn wire on the take-up rack to the wire drawing machine, and draw the medium drawn wire to Φ1.90mm; (3) The medium-drawn steel wire is sequentially subjected to degreasing, heating furnace, AQ quenching, water cooling, pickling, water washing, copper plating, water washing, galvanizing, water washing, hot water washing, MF medium frequency diffusion, water cooling, phosphoric acid immersion, water washing, soap immersion, and finally collected on a large I-shaped wheel to obtain a Φ1.90 mm brass-plated steel wire with a brass coating on the surface of the steel wire and a copper content of 63.5±2.5% in the coating; (4) The steel wire is drawn to 0.35 mm through a multi-pass die, and the diameter of the wet-drawn single wire is 0.35 ± 0.05 mm; (5) The wet-drawn monofilaments are used for steel cords with specifications of 2+2x0.35 HT, with 2 Φ0.35 mm monofilaments as core wires and 2 Φ0.35 mm monofilaments as outer layers. The desired finished product 2+2x0.35 HT steel cord is obtained by double twisting.

3. The use of the electric furnace wire rod in the production of steel cord according to claim 1, characterized in that: Applications that replace 72Cr in 3+8x0.33 ST specifications include: (1) Mechanically descaling the surface of the electric furnace wire rod, then pickling, water washing, boron coating, and drawing in sequence, roughly drawing the electric furnace wire rod to Φ3.25 mm, and then collecting it on the wire take-up rack; (2) Pull the thick drawn wire on the take-up rack to the wire drawing machine, and draw the medium drawn wire to Φ2.05mm; (3) The medium-drawn steel wire is sequentially subjected to degreasing, heating furnace, AQ quenching, water cooling, pickling, water washing, copper plating, water washing, galvanizing, water washing, hot water washing, MF medium frequency diffusion, water cooling, phosphoric acid immersion, water washing, soap immersion, and finally collected on a large I-shaped wheel to obtain a Φ2.05 mm brass-plated steel wire with a brass coating on the surface of the steel wire and a copper content of 63.5±2.5% in the coating; (4) The steel wire is drawn to 0.33 mm through a multi-pass die, and the diameter of the wet-drawn single wire is 0.33 ± 0.05 mm; (5) The wet-drawn monofilaments are used for 3+8x0.33 ST steel cords, with 3 Φ0.33 mm monofilaments as the core wires and 8 Φ0.33 mm monofilaments as the outer layer. The desired finished 3+8x0.33 ST steel cords are obtained by double twisting.

4. The use of the electric furnace wire rod in the production of steel cord according to claim 1, characterized in that: Applications that replace 72Cr in 2x0.30 ST specifications include: (1) Mechanically descaling the surface of the electric furnace wire rod, then pickling, water washing, boron coating, and drawing in sequence, roughly drawing the electric furnace wire rod to Φ3.25 mm, and then collecting it on the wire take-up rack; (2) Pull the thick drawn wire on the take-up rack to the wire drawing machine, and draw the medium drawn wire to Φ1.90mm; (3) The medium-drawn steel wire is sequentially subjected to degreasing, heating furnace, AQ quenching, water cooling, pickling, water washing, copper plating, water washing, galvanizing, water washing, hot water washing, MF medium frequency diffusion, water cooling, phosphoric acid immersion, water washing, soap immersion, and finally collected on a large I-shaped wheel to obtain a Φ1.90 mm brass-plated steel wire with a brass coating on the surface of the steel wire and a copper content of 63.5±2.5% in the coating; (4) The steel wire is drawn to 0.30 mm through a multi-pass die, and the diameter of the wet-drawn single wire is 0.30 ± 0.05 mm; (5) The wet-drawn monofilament is used for the steel cord of 2x0.30 ST specification. Two Φ0.30 mm monofilaments are double-twisted to produce the required finished product 2x0.30 ST steel cord.

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