Pretreatment process and device for cold heading finished wire

Abstract

The invention discloses a pretreatment process and device for cold-heading finished wires, which comprises the following steps of: loosening a wire coil to loosen the wire coil, feeding the wire coil into a pretreatment device for heat treatment, and introducing nitrogen in the preheating process to completely replace original air, the method comprises the following steps: firstly, introducing a mixture of nitrogen and hydrogen in the processes of heating, heat preservation and slow cooling, and finally carrying out natural cooling, so that after the wire rod is loosened, the high temperature can enter the inner wall of the wire rod more easily, the heating uniformity is improved, and the high temperature can further enter the wire rod more easily due to the fact that heat flow is driven by ventilation.

Description

Technical Field

[0001] The present invention relates to the technical field of heat treatment, and particularly to a pretreatment process and device for cold-heading finished wire. Background Art

[0002] Bolts are usually prepared by cutting steel wires into appropriate lengths, cold-heading the screw heads, and then threading them. The storage and transportation of steel wires usually coil them into annular wire coils to increase the length of the steel wires within a limited area.

[0003] In the production of bolts, it is necessary to heat-treat the steel wire raw materials first. In the prior art, the wire coils are usually stacked directly in the heat treatment furnace body, which causes the steel wires inside the stack to be heated slowly, resulting in uneven heating and cooling inside and outside, and uneven heat treatment effects. Summary of the Invention

[0004] In order to solve the above deficiencies in the prior art, the present invention provides a pretreatment process and device for cold-heading finished wire.

[0005] In order to achieve the above technical effects, the present invention adopts the following solutions:

[0006] A pretreatment process for cold-heading finished wire includes:

[0007] S1. Loosening the material: rebinding the wire coil with a bundling tape and then cutting off the original bundling tape to make the wire coil more loose;

[0008] S2. Loading: feeding the loosened wire coil into the pretreatment device and hanging it in the pretreatment device for heat treatment;

[0009] S3. Preheating: gradually raising the temperature from room temperature to 400 °C at a heating rate not greater than 150 °C / h, and continuously introducing nitrogen to completely displace the air at a flow rate of 10 cubic meters per hour;

[0010] S4. Heating to spheroidization: after preheating, continue to heat to 750 °C at a heating rate not greater than 100 °C / h. During this process, switch to introducing a mixed gas of nitrogen and hydrogen at a flow rate of 15 cubic meters per hour;

[0011] S5. Insulation: keep the temperature constant at 750 °C for 3 hours, and maintain the introduction of the mixed gas of nitrogen and hydrogen at a flow rate of 10 cubic meters per hour;

[0012] S6. Slow cooling: gradually lower the temperature to 600 °C at a cooling rate of 15 °C / h, and maintain the introduction of the mixed gas of nitrogen and hydrogen at a flow rate of 8 cubic meters per hour;

[0013] S7. Natural cooling: The temperature is gradually cooled to room temperature by natural cooling, and ventilation stops during this stage.

[0014] S8. Unloading: Take out the heat-treated wire coil from the pretreatment device.

[0015] A pretreatment device includes:

[0016] A furnace body, with a furnace door matching on one side of the furnace body, and a first heating component is arranged inside the furnace body.

[0017] A support frame, which is installed in the middle of the furnace body and rotates through a rotating table. The rotating table is driven to rotate by a first driving mechanism. At least two suspension rods extend outwards towards the surroundings at the upper end of the support frame.

[0018] An air supply pipe, one end of the air supply pipe is connected to the furnace body, and the other end of the air supply pipe is respectively connected to a nitrogen gas tank and a hydrogen gas tank through a nitrogen gas pipe and a hydrogen gas pipe. A first flow valve and a second flow valve are respectively arranged on the nitrogen gas pipe and the hydrogen gas pipe. An air pump and a second heating component are arranged on the air supply pipe.

[0019] An exhaust pipe, one end of the exhaust pipe is connected to the furnace body.

[0020] In a preferred technical solution, the outer end of the suspension rod tilts upwards.

[0021] In a preferred technical solution, the first driving mechanism includes a first motor. The rotating table is rotatably installed at the bottom of the furnace body. The first motor is installed at the lower end of the furnace body, and the output end of the first motor is fixedly connected to the rotation center of the rotating table.

[0022] In a preferred technical solution, the first heating component includes a plurality of electric heating tubes installed on the inner wall of the furnace body, and the length of the electric heating tubes is set vertically.

[0023] In a preferred technical solution, the second heating component includes a plurality of electric heating wires arranged on the air supply pipe.

[0024] In a preferred technical solution, a first temperature sensor is arranged inside the furnace body, and a second temperature sensor is arranged on the air supply pipe.

[0025] In a preferred technical solution, a preheating component is arranged on the air supply pipe. The preheating component is located in the direction away from the furnace body of the second heating component. The preheating component includes a preheating box in the middle of the air supply pipe. Independent air inlet chambers and air outlet chambers are respectively arranged at the left and right ends of the preheating box. The air inlet chamber and the air outlet chamber are respectively communicated with the air supply pipes at the left and right ends. The air inlet chamber and the air outlet chamber are communicated through a plurality of heat exchange tubes passing through the preheating box. Air inlet pipes and air outlet pipes are respectively arranged at the upper and lower ends of the preheating box. The air inlet pipe is connected to the other end of the exhaust pipe.

[0026] In a preferred technical solution, a spiral air passage portion is provided on the air supply pipe, and a plurality of convex blocks are provided on both inner walls of the spiral air passage portion along the spiral extension direction.

[0027] Compared with the prior art, the beneficial effects are as follows:

[0028] 1. In the present invention, the bundled wire rod coils are re-bundled first to make the wire rod coils looser, so that hot air can more easily enter the interior of the wire rod coils, thereby increasing the contact area between the wire rod coils and air and improving the uniformity of heating and cooling. In addition, during the heat treatment process, air is supplied, and the flow of the gas will drive the high temperature through the wire rod coils, further making it easier for the high temperature to enter the interior of the wire rod coils.

[0029] 2. In the present invention, the wire rod coils of the steel wire are sent into the furnace body and suspended on the suspension rods. Only one coil of the wire rod coils of the steel wire is suspended on each suspension rod, so as to separate multiple coils of wire rod coils, reduce stacking and extrusion, thereby increasing the heating area and improving the uniformity of heating and cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic cross-sectional view of the present invention.

[0031] Reference numerals: 1. Furnace body; 2. Furnace door; 3. Rotary table; 4. Support frame; 5. Suspension rod; 6. First motor; 7. Electric heating tube; 8. First temperature sensor; 9. Air supply pipe; 10. Electric heating wire; 11. Second temperature sensor; 12. Air pump; 13. First flow valve; 14. Nitrogen tank; 15. Second flow valve; 16. Hydrogen tank; 17. Preheating box; 18. Air outlet chamber; 19. Air inlet chamber; 20. Heat exchange tube; 21. Wire rod coil; 22. Spiral air passage portion; 23. Convex block. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0033] A pre-treatment process and device for cold-heading finished wire, wherein the process includes:

[0034] S1. Loosening the material, re-bundling the wire rod coils 21 with a bundling tape, and then cutting off the original bundling tape to make the wire rod material looser;

[0035] S2. Loading the material, sending the loosened wire rod material into the pre-treatment device and suspending it in the pre-treatment device for heat treatment;

[0036] S3. Preheat, gradually increase the temperature from room temperature to 400 °C at a heating rate not exceeding 150 °C / h, and simultaneously continuously introduce nitrogen to completely displace the air at a flow rate of 10 cubic meters per hour.

[0037] S4. Heat up to spheroidize. After preheating is completed, continue to heat up to 750 °C at a heating rate not exceeding 100 °C / h. During this process, switch to introducing a mixed gas of nitrogen and hydrogen at a flow rate of 15 cubic meters per hour.

[0038] S5. Insulate, maintain a constant temperature of 750 °C for 3 hours, and continue to introduce the mixed gas of nitrogen and hydrogen at a flow rate of 10 cubic meters per hour.

[0039] S6. Slowly cool, gradually reduce the temperature to 600 °C at a cooling rate of 15 °C / h, and continue to introduce the mixed gas of nitrogen and hydrogen at a flow rate of 8 cubic meters per hour.

[0040] S7. Naturally cool, gradually cool the temperature to room temperature by natural cooling, and stop gas introduction at this stage.

[0041] S8. Unload the material, take out the heat-treated wire rod coil from the pretreatment device.

[0042] In this process, first re-bundle the bundled wire rod coils 21 of steel wire to make the wire rod coils 21 looser, so that hot air can more easily enter the interior of the wire rod coils 21, thereby increasing the contact area between the wire rod coils 21 and the air and improving the uniformity of heating and cooling. In addition, during the heat treatment process, gas is supplied, and the flow of the gas will drive the high temperature through the wire rod coils 21, further making it easier for the high temperature to enter the interior of the wire rod coils 21.

[0043] The pretreatment device includes: a furnace body 1, a support frame 4, a gas supply pipe 9, and an exhaust pipe.

[0044] A furnace door 2 is correspondingly arranged on one side of the furnace body 1, and a first heating component is arranged inside the furnace body 1 to heat the inside of the furnace body 1 through the heating component.

[0045] The support frame 4 is installed in the middle of the furnace body 1 to rotate through a rotating table 3, the rotating table 3 is driven to rotate by a first driving mechanism, and at least two suspension rods 5 are arranged at the upper end of the support frame 4 and extend towards the surroundings for suspending the wire rod coils 21 of steel wire.

[0046] One end of the gas supply pipe 9 is connected to the furnace body 1. The gas supply pipe 9 is connected to the lower end of the furnace body 1. The other end of the gas supply pipe 9 is respectively connected to the nitrogen gas tank 14 and the hydrogen gas tank 16 through the nitrogen gas pipe and the hydrogen gas pipe. The first flow valve 13 and the second flow valve 15 are respectively arranged on the nitrogen gas pipe and the hydrogen gas pipe. An air pump 12 and a second heating component are arranged on the gas supply pipe 9. Separate nitrogen gas or a mixed gas of nitrogen gas and hydrogen gas is sent into the furnace body 1 through the gas supply pipe 9. The ratio of nitrogen gas to hydrogen gas is adjusted through the low flow valve and the second flow valve 15. The gas in the gas supply pipe 9 is heated to the same temperature as the furnace body 1 by the second heating component and then sent into the furnace body 1 to avoid uneven temperature distribution in the furnace body 1 caused by the sent gas.

[0047] One end of the exhaust pipe is connected to the furnace body 1. The exhaust pipe is connected to the upper end of the furnace body 1. Exhaust gas is discharged through the exhaust pipe.

[0048] The wire rod coil 21 of the steel wire is sent into the furnace body 1 by a forklift and suspended on the suspension rod 5. When suspending, the rotating table 3 is rotated to change the direction of the support frame 4. The wire rod coil 21 is hung on each suspension rod 5. Preheating and heating are carried out through the first heating component. The first flow valve 13 and the second flow valve 15 are opened to supply nitrogen gas and hydrogen gas, which are sent into the furnace body 1 through the gas supply pipe 9, and the gas sent into the furnace body 1 is heated by the second heating component.

[0049] Only one coil of the wire rod coil 21 of the steel wire is suspended on each suspension rod 5, so as to separate multiple coils of wire rod coils 21, reduce stacking and extrusion, thereby increasing the heating area. And during the heating process, the support frame 4 drives the wire rod coil 21 to rotate, improving the uniformity of heating and cooling.

[0050] At the same time, gas is continuously sent into the furnace body 1 through the gas supply pipe 9 and discharged from the exhaust pipe, driving the flow of the high-temperature gas in the furnace body 1. The high temperature is more likely to enter the inside of the wire rod coil 21, further improving the heating uniformity.

[0051] In a preferred technical solution, the outer end of the suspension rod 5 tilts upward to form a limit to prevent the wire rod coil 21 suspended on the suspension rod 5 from falling off.

[0052] In a preferred technical solution, the first driving mechanism includes a first motor 6. The rotating table 3 is rotatably installed at the bottom of the furnace body 1. The first motor 6 is installed at the lower end of the furnace body 1. The output end of the first motor 6 is fixedly connected to the rotation center of the rotating table 3. The first motor 6 drives the rotating table 3 to rotate, and then drives the support frame 4 to rotate.

[0053] In a preferred technical solution, the first heating component includes a plurality of electric heating tubes 7 installed on the inner wall of the furnace body 1. The length of the electric heating tube 7 is arranged vertically.

[0054] Preferred technical solution: The second heating component includes a plurality of heating wires 10 provided on the gas supply pipe 9.

[0055] Preferred technical solution: A first temperature sensor 8 is provided in the furnace body 1, and a second temperature sensor 11 is provided on the gas supply pipe 9.

[0056] Preferred technical solution: A preheating component is provided on the gas supply pipe 9. The preheating component is located in the direction away from the furnace body 1 of the second heating component. The preheating component includes a preheating box 17 located in the middle of the gas supply pipe 9. An independent intake chamber 19 and an outlet chamber 18 are respectively provided at the left and right ends of the preheating box 17. The intake chamber 19 and the outlet chamber 18 are respectively communicated with the gas supply pipes 9 at the left and right ends. The intake chamber 19 and the outlet chamber 18 are communicated through a plurality of heat exchange pipes 20 passing through the preheating box 17. An intake pipe and an outlet pipe are respectively provided at the upper and lower ends of the preheating box 17. The other ends of the intake pipe and the exhaust pipe are connected.

[0057] Directly discharging the high-temperature gas discharged from the exhaust pipe will cause waste of heat. The high-temperature gas is sent into the preheating box 17. When the gas in the gas supply pipe 9 passes through a plurality of heat exchange pipes 20, it exchanges heat with the high-temperature gas in the preheating box 17, thereby performing preheating.

[0058] Preferred technical solution: The gas supply pipe 9 has a spiral air duct portion 22. A plurality of convex blocks 23 are provided on both inner walls of the spiral air duct portion 22 along the spiral extension direction. When the mixed gas of nitrogen and hydrogen enters the spiral air duct portion 22, due to spiral transportation, turbulence is easily generated, so that nitrogen and hydrogen are evenly mixed. Moreover, the convex blocks 23 on both sides of the spiral air duct portion 22 will block the air flow velocity at both sides, thereby causing the air flow velocity in the middle to be greater than that at both sides. The velocity difference will generate turbulence, further making nitrogen and hydrogen evenly mixed.

[0059] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0061] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

Claims

1. A pre-treatment process for cold heading finished wire, characterized in that: include: S1, loosening the wire rod (21), re-binding the wire rod with a binding tape, and then cutting off the original binding tape to make the wire rod looser; S2, feeding, feeding the loosened wire coil into the pre-treatment device, and hanging it in the pre-treatment device for heat treatment; S3, preheating, gradually raising the temperature from room temperature to 400°C, with a heating rate of no more than 150°C / h, and continuously introducing nitrogen to completely replace the air, with a ventilation flow rate of 10 cubic meters / hour; S4, heating to spheroidization, after preheating, continue to heat to 750 ° C, the heating rate is not more than 100 ° C / h, during this process, switch to a mixed gas of nitrogen and hydrogen, the flow rate of ventilation is 15 cubic meters / hour; S5, heat preservation, constant temperature of 750 ° C for 3 hours, maintaining the introduction of a mixed gas of nitrogen and hydrogen, the flow rate of ventilation is 10 cubic meters / hour; S6, slowly cooling, the temperature gradually decreases to 600°C, the cooling rate is 15°C / h, and the mixed gas of nitrogen and hydrogen is maintained to be introduced, and the flow rate of the ventilation is 8 cubic meters / hour; S7, natural cooling, the temperature is cooled to room temperature by natural cooling, and ventilation is stopped at this stage; S8, unloading, taking out the heat-treated wire coil from the pre-treatment device.

2. A pre-processing device as claimed in claim 1, characterized in that: include: A furnace body (1), one side of the furnace body (1) is matched with a furnace door (2), and a first heating component is arranged inside the furnace body (1); A support frame (4), the support frame (4) is mounted on the middle part of the furnace body (1) via a rotating platform (3) for rotation, the rotating platform (3) is driven to rotate by a first driving mechanism, and the upper end of the support frame (4) is extended in all directions and is provided with at least two suspension rods (5); A gas supply pipe (9), one end of the gas supply pipe (9) is connected to the furnace body (1), and the other end of the gas supply pipe (9) is connected to a nitrogen tank (14) and a hydrogen tank (16) through a nitrogen pipe and a hydrogen pipe, respectively, a first flow valve (13) and a second flow valve (15) are provided on the nitrogen pipe and the hydrogen pipe, respectively, and an air pump (12) and a second heating component are provided on the gas supply pipe (9); An exhaust pipe, one end of which is connected to the furnace body (1).

3. The pre-treatment process and device for cold heading finished wire according to claim 1, characterized in that: The outer end of the hanging rod (5) is tilted upward.

4. The pre-treatment process and device for cold heading finished wire according to claim 1, characterized in that: The first driving mechanism comprises a first motor (6); the rotating table (3) is rotatably mounted on the bottom of the furnace body (1); the first motor (6) is mounted on the lower end of the furnace body (1); and the output end of the first motor (6) is fixedly connected to the rotation center of the rotating table (3).

5. The pre-treatment process and device for cold heading finished wire according to claim 1, characterized in that: The first heating component comprises a plurality of electric heating tubes (7) mounted on the inner wall of the furnace body (1), and the length of the electric heating tubes (7) is arranged vertically.

6. The pre-treatment process and device for cold heading finished wire according to claim 1, characterized in that: The second heating component comprises a plurality of electric heating wires (10) arranged on the air supply pipe (9).

7. The pre-treatment process and device for cold heading finished wire according to claim 1, characterized in that: A first temperature sensor (8) is provided in the furnace body (1), and a second temperature sensor (11) is provided on the gas supply pipe (9).

8. The pre-treatment process and device for cold heading finished wire according to claim 1, characterized in that: The air supply pipe (9) is provided with a preheating component, and the preheating component is located in a direction away from the furnace body (1) of the second heating component. The preheating component includes a preheating box (17) located in the middle of the air supply pipe (9). The left and right ends of the preheating box (17) are respectively provided with independent air inlet chambers (19) and air outlet chambers (18). The air inlet chambers (19) and the air outlet chambers (18) are respectively connected to the air supply pipes (9) at the left and right ends. The air inlet chambers (19) and the air outlet chambers (18) are connected through a plurality of heat exchange pipes (20) passing through the preheating box (17). The upper and lower ends of the preheating box (17) are respectively provided with an air inlet pipe and an air outlet pipe, and the air inlet pipe is connected to the other end of the exhaust pipe.

9. The pre-treatment process and device for cold heading finished wire according to claim 1, characterized in that: The air supply pipe (9) is provided with a spiral airway portion (22), and inner walls on both sides of the spiral airway portion (22) are provided with a plurality of protrusions (23) along the spiral extension direction.

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