A heat treatment device for cold-drawn steel wire

Abstract

This invention discloses a heat treatment device for cold-drawn steel wire, belonging to the technical field of metal wire rope products such as steel cord and tire bead. It includes a quenching tank, with a first roller and a second roller respectively arranged on the front and rear sides of the quenching tank. The first and second rollers are of the same size and arranged parallel to each other in the horizontal direction. Grooves a and b are alternately arranged along the axial direction on both the first and second rollers, with the radial diameter of groove a being smaller than that of groove b. A portion of the steel wire first passes through groove a on the first roller, then is immersed in the quenching liquid in the quenching tank, and finally passes through groove a on the second roller. Another portion of the steel wire first passes through groove b on the first roller, then is immersed in the quenching liquid in the quenching tank, and finally passes through groove b on the second roller. This invention can reduce the strength variation between batches of steel wires and ensure the strength stability of the steel wires.

Description

Technical Field

[0001] This invention relates to a heat treatment device for cold-drawn steel wire, belonging to the technical field of metal wire rope products such as steel cord and tire bead. Background Technology

[0002] With the increasing demands for green and low-carbon development and lightweight tires, the strength of steel cords used in radial tires is becoming increasingly higher, with the strength of the single filament reaching over (4400-2000*D) MPa (where D is the diameter of the single filament). The strength of the single filament in steel cord is primarily determined by the total compression ratio during cold drawing and the initial strength of the material. A higher total compression ratio results in a greater strength increase; similarly, a higher initial strength of the steel wire leads to higher single filament strength under the same compression ratio. For ultra-high strength steel cords used in radial tires, due to their high strength requirements, the compression ratio is often close to 98%. Under such high compression ratios during cold drawing, the entire processing is highly sensitive to the initial steel wire strength. This manifests in several ways: if the initial steel wire strength is slightly too high, the resulting single filament strength is sufficient, but the toughness is insufficient, leading to severe wire breakage during subsequent twisting and a low yield; if the initial steel wire strength is slightly too low, the resulting single filament toughness is sufficient, but the single filament strength is insufficient, resulting in steel cord strength that does not meet customer requirements. Therefore, it is crucial to strictly control the strength fluctuation range of the initial steel wire. Industry insiders know that after the initial steel wire is drawn to the required size from 5.5mm wire rod, it needs to undergo a heat treatment process to obtain the microstructure and strength required for further processing. During the entire heat treatment process, multiple steel wires typically pass through the heat treatment furnace in parallel, with the number reaching 48 or more, which significantly improves the efficiency of the heat treatment process. However, while efficiency is increased, ensuring the strength stability of these 48 steel wires remains a problem. Current technology urgently needs a method to control the strength variation of steel wires in the same furnace to ensure the strength stability of the steel wires. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a heat treatment device for cold-drawn steel wire that can reduce the strength difference between a batch of steel wires and ensure the strength stability of the steel wire.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A heat treatment apparatus for cold-drawn steel wire includes a quenching tank. A first roller and a second roller are respectively arranged on the front and rear sides of the quenching tank. The first roller and the second roller are of the same size and are arranged in parallel in the horizontal direction. Grooves a and b are alternately arranged on the first roller and the second roller along the axial direction. The radial diameter of groove a is smaller than that of groove b. A portion of the steel wire first passes through groove a on the first roller, then is immersed in the quenching liquid in the quenching tank, and finally passes through groove a on the second roller. Another portion of the steel wire first passes through groove b on the first roller, then is immersed in the quenching liquid in the quenching tank, and finally passes through groove b on the second roller.

[0006] The number of steel wires is M, and the sum of the number of grooves a and groove b on the first and second idlers is M, where M ranges from 40 to 50.

[0007] The diameter of the steel wire is between 0.9 and 2.5 mm.

[0008] The radial diameter of groove a is d2, and the radial diameter of groove b is d1, satisfying 2cm≤d1-d2≤3cm.

[0009] The distance between adjacent grooves a and b is H, which satisfies H≥1.5cm.

[0010] The steel wire is immersed in the quenching liquid in the quenching tank to a depth of 1~3cm.

[0011] The first and second idlers are mounted on the height adjustment device.

[0012] The quenching tank is 1.5m wide, and the temperature of the quenching liquid in the quenching tank is controlled at 90±5℃.

[0013] The beneficial effects of the present invention are as follows: In the present invention, grooves a and groove b are alternately provided on the first roller and the second roller along the axial direction. The radial diameter of groove a is smaller than that of groove b. This can increase the spacing between steel wires without changing the overall size of the quenching tank, reduce the temperature field interference between adjacent steel wires when the steel wires are cooled in the coolant, thereby improving the strength variation of the entire batch of steel wires and ensuring the strength stability of the steel wires. Attached Figure Description

[0014] Figure 1 This is a side sectional view of the heat treatment apparatus for cold-drawn steel wire according to the present invention;

[0015] Figure 2 This is a schematic diagram of the structure of the first idler roller or the second idler roller in this invention;

[0016] Figure 3This is a schematic diagram of the existing technology for the routing of steel wires in a quenching tank, where position A represents the steel wire and position B represents the temperature field where adjacent steel wires do not interfere with each other.

[0017] Figure 4 This is a schematic diagram of the steel wire routing in the quenching tank in this invention, where position C represents the steel wire and position D represents the temperature field where adjacent steel wires do not interfere with each other;

[0018] The attached figures are labeled as follows: 1-First idler roller; 2-Quenching tank; 3-Steel wire; 4-Second idler roller; 5-Groove a; 6-Groove b. Detailed Implementation

[0019] 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.

[0020] Example 1

[0021] like Figure 1 and Figure 2 As shown, this invention discloses a heat treatment device for cold-drawn steel wire, including a quenching tank 2. A first roller 1 and a second roller 4 are respectively arranged on the front and rear sides of the quenching tank 2. The first roller 1 and the second roller 4 are of the same size and are arranged parallel to each other in the horizontal direction. Grooves a5 and b6 are alternately arranged on both the first roller 1 and the second roller 4 along the axial direction, and the total number of grooves is consistent with the number of steel wires 3 being heat-treated in the furnace. Let the number of steel wires be M, and the diameter of the steel wires 3 be between 0.9 and 2.5 mm. The sum of the number of grooves a and b on the first roller and the second roller is M, and M ranges from 40 to 50.

[0022] This invention features two different types of grooves, with groove a5 having a smaller radial diameter than groove b6. The radial diameter of groove a5 is d2, and the radial diameter of groove b6 is d1, satisfying 2cm ≤ d1 - d2 ≤ 3cm. The distance between adjacent grooves a5 and b6 is H, satisfying H ≥ 1.5cm. A portion of the steel wire 3 first passes through groove a5 on the first idler roller 1, then is immersed in the quenching liquid in the quenching tank 2, and finally passes through groove a5 on the second idler roller 4. Another portion of the steel wire 3 first passes through groove b6 on the first idler roller 1, then is immersed in the quenching liquid in the quenching tank 2, and finally passes through groove b6 on the second idler roller 4. The steel wire 3 passing through groove a5 and the steel wire 3 passing through groove b6 are misaligned vertically, increasing the distance between two adjacent steel wires 3. The first idler roller 1 and the second idler roller 4 are mounted on a height adjustment device, and their vertical height is adjustable to ensure that the immersion depth of each steel wire 3 in the quenching liquid is 1~3cm.

[0023] Taking the heat treatment process of 1.55mm diameter 86 carbon cold-drawn steel wire as an example, a total of 48 heat-treated steel wires are processed. The quenching tank 2 is 1.5m wide, the wire spacing H is set to 1.5cm, and the diameter of grooves a5 and b6 is 3mm. The dimensions of d1 in groove b6 and d2 in groove a5 are 80mm and 50mm respectively. High-molecular-weight water quenching fluid is used, and the temperature is controlled at 90±5℃. The heights of the first and second rollers 1 and 4 are controlled so that the immersion depth of the wires in groove b6 is 1~1.5cm, while the immersion depth of the wires in groove a5 is 2.5~3cm. Both types of wires meet the immersion depth requirement of 1~3cm. Figure 3 Compared with the existing technology used in this invention, Figure 4 The distance between the steel wires was increased by 41%.

[0024] Example 2

[0025] like Figure 1 and Figure 2 As shown, this invention discloses a heat treatment device for cold-drawn steel wire, including a quenching tank 2. A first roller 1 and a second roller 4 are respectively arranged on the front and rear sides of the quenching tank 2. The first roller 1 and the second roller 4 are of the same size and are arranged parallel to each other in the horizontal direction. Grooves a5 and b6 are alternately arranged on both the first roller 1 and the second roller 4 along the axial direction, and the total number of grooves is consistent with the number of steel wires 3 being heat-treated in the furnace. Let the number of steel wires be M, and the diameter of the steel wires 3 be between 0.9 and 2.5 mm. The sum of the number of grooves a and b on the first roller and the second roller is M, and M ranges from 40 to 50.

[0026] This invention features two different types of grooves, with groove a5 having a smaller radial diameter than groove b6. The radial diameter of groove a5 is d2, and the radial diameter of groove b6 is d1, satisfying 2cm ≤ d1 - d2 ≤ 3cm. The distance between adjacent grooves a5 and b6 is H, satisfying H ≥ 1.5cm. A portion of the steel wire 3 first passes through groove a5 on the first idler roller 1, then is immersed in the quenching liquid in the quenching tank 2, and finally passes through groove a5 on the second idler roller 4. Another portion of the steel wire 3 first passes through groove b6 on the first idler roller 1, then is immersed in the quenching liquid in the quenching tank 2, and finally passes through groove b6 on the second idler roller 4. The steel wire 3 passing through groove a5 and the steel wire 3 passing through groove b6 are misaligned vertically, increasing the distance between two adjacent steel wires 3. The first idler roller 1 and the second idler roller 4 are mounted on a height adjustment device, and their vertical height is adjustable to ensure that the immersion depth of each steel wire 3 in the quenching liquid is 1~3cm.

[0027] Taking the heat treatment process of 1.55mm diameter 82 carbon cold-drawn steel wire as an example, a total of 48 heat-treated steel wires are processed. The quenching tank 2 is 1.5m wide, the wire spacing H is set to 1.5cm, and the diameter of grooves a5 and b6 is 3mm. The dimensions of d1 in groove b6 and d2 in groove a5 are 80mm and 60mm respectively. High-molecular-weight water quenching fluid is used, and the temperature is controlled at 90±5℃. The heights of the first and second rollers 1 and 4 are controlled so that the immersion depth of the wires in groove b6 is 1~1.5cm, while the immersion depth of the wires in groove a5 is 2.5~3cm. Both types of wires meet the immersion depth requirement of 1~3cm. Figure 3 Compared with the existing technology used in this invention, Figure 4 The distance between the steel wires has been increased by 20%.

[0028] Comparative Example 1

[0029] The difference between Comparative Example 1 and Example 1 is that the Comparative Example uses a conventional idler roller with only one type of groove. A schematic diagram of the cross-section of the steel wire in the quenching liquid is shown below. Figure 3 As shown, taking the heat treatment process of 1.55mm diameter 86 carbon cold-drawn steel wire as an example, the entire batch of heat-treated steel wires totals 48. The quenching tank width is 1.5m, the wire spacing H is set to 1.5cm, the groove diameter is 3mm, and the diameter of the groove in the idler roller is 80mm. The quenching fluid used is a high-molecular-weight water quenching fluid, and the quenching fluid temperature is controlled at 90±5℃. The heights of the first and second idler rollers are controlled to ensure that the immersion depth of the steel wire located in the groove is 1~3cm.

[0030] Comparative Example 2

[0031] The difference between Comparative Example 2 and Example 2 is that the Comparative Example uses a conventional idler roller with only one type of groove. A schematic diagram of the cross-section of the steel wire in the quenching liquid is shown below. Figure 3 As shown, taking the heat treatment process of 1.55mm diameter 82 carbon cold-drawn steel wire as an example, the entire batch of heat-treated steel wires totals 48. The quenching tank width is 1.5m, the wire spacing H is set to 1.5cm, the groove diameter is 3mm, and the groove diameter in the idler roller is 80mm. The quenching fluid used is a high-molecular-weight water quenching fluid, and the quenching fluid temperature is controlled at 90±5℃. The heights of the first and second idler rollers are controlled to ensure that the immersion depth of the steel wire located in the groove is 1~3cm.

[0032] Table 1 Comparison of test results between embodiments of the present invention and comparative examples

[0033]

[0034] Table 1 presents statistical data on the strength of steel wires after heat treatment in Examples 1 and 2 of the present invention and in conventional techniques. According to the data in Table 1, the strength variation of the entire batch of steel wires after heat treatment in the embodiments of the present invention is small. This proves that the present invention can increase the spacing between steel wires without changing the overall size of the quenching tank, reduce the temperature field interference between adjacent steel wires when the steel wires are cooled in the coolant, thereby improving the strength variation of the entire batch of steel wires and ensuring the strength stability of the steel wires.

[0035] 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 principle 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 heat treatment apparatus for cold-drawn steel wire, characterized in that: The quenching tank (2) includes a first roller (1) and a second roller (4) on its front and rear sides respectively. The first roller (1) and the second roller (4) are the same size and are arranged in parallel in the horizontal direction. The first roller (1) and the second roller (4) are provided with grooves a (5) and grooves b (6) alternately along the axial direction. The radial diameter of groove a (5) is smaller than that of groove b (6). A portion of the steel wire (3) first passes through the groove a (5) on the first roller (1), then is immersed in the quenching liquid in the quenching tank (2), and finally passes through the groove a (5) on the second roller (4). Another portion of the steel wire (3) first passes through the groove b (6) on the first roller (1), then is immersed in the quenching liquid in the quenching tank (2), and finally passes through the groove b (6) on the second roller (4).

2. The heat treatment apparatus for cold-drawn steel wire according to claim 1, characterized in that: The number of steel wires (3) is M, and the sum of the number of grooves a (5) and grooves b (6) on the first roller (1) and the second roller (4) is M, where M ranges from 40 to 50.

3. The heat treatment apparatus for cold-drawn steel wire according to claim 1, characterized in that: The diameter of the steel wire (3) is between 0.9 and 2.5 mm.

4. The heat treatment apparatus for cold-drawn steel wire according to claim 1, characterized in that: The radial diameter of the groove a (5) is d2, and the radial diameter of the groove b (6) is d1, satisfying 2cm≤d1-d2≤3cm.

5. The heat treatment apparatus for cold-drawn steel wire according to claim 1, characterized in that: The distance between adjacent grooves a (5) and b (6) is H, which satisfies H≥1.5cm.

6. The heat treatment apparatus for cold-drawn steel wire according to claim 1, characterized in that: The steel wire (3) is immersed in the quenching liquid in the quenching tank (2) to a depth of 1~3cm.

7. The heat treatment apparatus for cold-drawn steel wire according to claim 1, characterized in that: The first idler (1) and the second idler (4) are mounted on the height adjustment device.

8. The heat treatment apparatus for cold-drawn steel wire according to claim 1, characterized in that: The quenching tank (2) has a width of 1.5m, and the temperature of the quenching liquid in the quenching tank (2) is controlled at 90±5℃.

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