A wire softening furnace for continuous drawing and a softening method thereof

Abstract

This invention relates to a metal wire softening furnace for continuous drawing and its softening method, belonging to the field of metal material processing and forming technology. The technical solution includes a furnace cover (11) and a furnace body (12). The furnace body (12) is rectangular, with a metal wire inlet and a metal wire outlet on opposite sides. A positioning wheel (2) is located near the metal wire inlet and outlet inside the furnace body (12), and several guide wheels (6) are located between the two positioning wheels (2). The two positioning wheels (2) and the guide wheels (6) cause the metal wire to form an S-shape inside the furnace body (12), and the S-shaped metal wire passes through several sets of induction coils (4). The furnace body (12) is composed of an outer steel plate (14), a middle layer of refractory bricks (15), and an inner layer of refractory cotton (16). The beneficial effects of this invention are: it can soften the metal wire during the drawing process, ensuring efficient and continuous production, while avoiding the disadvantage of large footprint of conventional tubular furnaces.

Description

Technical Field

[0001] This invention relates to a metal wire softening furnace for continuous drawing and a softening method thereof, belonging to the field of metal material processing and forming technology in the metallurgical industry. Background Technology

[0002] Metals possess plasticity and can be shaped and strengthened through cold working. Metal wire utilizes this property, using a cold drawing process to obtain cold-drawn wires with specific dimensions and mechanical properties, such as welding wire and steel wire. Because metal materials exhibit work hardening, they gradually harden during cold deformation. When hardening reaches a certain level, it can affect the drawing process, leading to jamming, breakage, and other accidents. Therefore, depending on the material, different softening treatments are required during the drawing process.

[0003] Currently, the conventional production process for welding wire is as follows: wire rod → softening treatment in a pit furnace / bogie hearth furnace → surface treatment → drawing → softening treatment → drawing → finished welding wire. However, because the softening treatment cannot be performed continuously, it must be done offline in a tube furnace, resulting in discontinuous production, significantly extending the growth time and reducing production efficiency. Furthermore, conventional tube furnaces are quite long, typically 10-40 meters, occupying a large area and wasting valuable space. Summary of the Invention

[0004] The purpose of this invention is to provide a metal wire softening furnace and its softening method for continuous drawing, which can soften the metal wire during the drawing process, ensuring efficient and continuous production, while avoiding the disadvantage of large footprint of conventional tube furnaces, and solving the problems existing in the background art.

[0005] The technical solution of this invention is:

[0006] A metal wire softening furnace for continuous drawing includes a furnace cover and a furnace body. The furnace body is rectangular, with a metal wire inlet and a metal wire outlet on opposite sides of the furnace body. A positioning wheel is provided near the metal wire inlet and the metal wire outlet inside the furnace body, and several guide wheels are provided between the two positioning wheels. The two positioning wheels and the several guide wheels cause the metal wire to form an S-shape inside the furnace body, and the S-shaped metal wire passes through several sets of induction coils.

[0007] The furnace body is composed of an outer steel plate, a middle layer of refractory bricks, and an inner layer of refractory cotton.

[0008] The furnace cover is fixed to the furnace body with high-temperature resistant bolts.

[0009] The furnace cover is equipped with a furnace cover lifting ring.

[0010] There are four guide wheels between the two positioning wheels, with one positioning wheel and two guide wheels forming a row, for a total of two rows.

[0011] The induction coil through which the S-shaped metal wire passes is ten groups, and the ten groups of induction coils are divided into two columns, five groups in each column.

[0012] The furnace body is provided with a gas protection device and a temperature measuring device.

[0013] The diameter of the metal wire is 1.9-2.1mm.

[0014] The gas protection device and the temperature measuring device on the furnace body are both well-known technical contents in the art. The gas protection device can adjust the type and flow of the gas sent to ensure that the metal wire is in an inert atmosphere in the furnace to prevent oxidation; the temperature measuring device is used to measure the temperature in the furnace.

[0015] A metal wire softening method for continuous drawing is operated according to the following steps:

[0016] Step one: when the drawing strength of the drawn metal wire reaches 2000MPa or more, a metal wire softening furnace defined above is used to soften the drawn metal wire;

[0017] Step two: when the drawn metal wire is softened, the softening furnace parameters are set according to the following formula according to the subsequent drawing strength requirements;

[0018] R=(642186*exp(-TEMP / 129.6)+637.9)*(0.01659*exp(-t / 6.9487)+0.9937)*(0.076*exp(-Z / 2.747)+0.998)

[0019] In the formula: R is the strength after annealing, unit MPa;

[0020] TEMP is the internal temperature of the softening furnace, unit ℃;

[0021] t is the residence time of the metal wire in the furnace, unit min;

[0022] Z is the number of groups of induction coils to be opened, unit group.

[0023] When the drawn metal wire is softened, the gas protection device is used to introduce a protective atmosphere into the softening furnace for 3-5min to ensure the inert atmosphere in the furnace.

[0024] The beneficial effects of the present application are:

[0025] 1) Avoiding offline softening treatment during the drawing process of the metal wire, achieving the purpose of continuous drawing, greatly improving the drawing processing efficiency of the metal wire, and reducing the production cost;

[0026] 2) The softening furnace is simple, occupies small area, and saves site resources;

[0027] 3) Based on the characteristics and requirements of the metal wire, the softening furnace can adjust the softening process at any time by adjusting parameters such as gas flow rate and heating power. The annealing furnace has a fast heating speed, does not require preheating, and has the characteristics of flexible and simple operation. Attached Figure Description

[0028] Figure 1 This is a structural diagram of the present invention;

[0029] Figure 2 This is the front view of the present invention;

[0030] Figure 3 This is a top view of the present invention;

[0031] Figure 4 This is a schematic diagram of the furnace wall structure of the present invention;

[0032] In the diagram: 1. Metal wire; 2. Positioning wheel; 3. Gas protection device; 4. Induction coil; 5. Partial magnification; 6. Guide wheel; 7. Furnace wall; 9. Temperature measuring device; 10. Furnace cover lifting ring; 11. Furnace cover; 12. Furnace body; 13. High-temperature resistant bolt; 14. Outer steel plate of softening furnace; 15. Middle refractory brick layer; 16. Inner refractory cotton layer. Implementation

[0033] The invention will be further described below with reference to the accompanying drawings and examples.

[0034] See attached document Figures 1-4 A metal wire softening furnace for continuous drawing includes a furnace cover 11 and a furnace body 12. The furnace body 12 is rectangular, and a metal wire inlet and a metal wire outlet are respectively provided on the corresponding two sides of the furnace body 12. A positioning wheel 2 is provided inside the furnace body 12 near the metal wire inlet and the metal wire outlet, and a number of guide wheels 6 are provided between the two positioning wheels 2. The two positioning wheels 2 and the number of guide wheels 6 make the metal wire form an S-shape inside the furnace body 12. The S-shaped metal wire passes through a number of sets of induction coils 4.

[0035] See attached document Figure 4 The furnace wall of the softening furnace has three layers: an outer layer of steel plate, a middle layer of refractory bricks, and an inner layer of refractory cotton.

[0036] See attached document Figure 2 , 3 The furnace cover 11 is fixed to the furnace body 12 by several high-temperature resistant bolts 13, and the furnace cover 11 is provided with a furnace cover lifting ring 10.

[0037] See attached document Figure 1 The positioning wheel 2 and guide wheel 6 are made of high-temperature resistant material. There are four guide wheels 6 between the two positioning wheels 2. One positioning wheel 2 and two guide wheels 6 form a row, and there are two rows in total. There are 10 sets of induction coils 4. The ten sets of induction coils 4 are divided into two rows, with five sets in each row. Each set is controlled independently.

[0038] The gas protection device 3 can adjust the type and flow of the gas to ensure that the wire is in an inert atmosphere in the furnace to prevent oxidation.

[0039] The specific treatment process of the wire is as follows:

[0040] ① When the wire is drawn to 2000-2100 MPa, annealing is arranged;

[0041] ② The annealing time t is determined according to the production rhythm, and the annealing temperature TEMP is determined according to the material properties;

[0042] According to the formula:

[0043] R=(642186×exp(-TEMP / 129.6)+637.9)×(0.01659×exp(-t / 6.9487)+0.9937)×(0.076×exp(-Z / 2.747)+0.998)

[0044] Determine the number of coil groups Z that need to be opened;

[0045] In the formula, R is the strength after annealing, unit MPa; TEMP is the display temperature detected by the temperature measuring device, unit ℃; t is the residence time of the wire in the furnace, unit min; Z is the number of coil groups that need to be opened, unit group;

[0046] ③ Set the annealing furnace parameters according to the parameter values calculated in step ②;

[0047] ④ Loosen the fastening bolt 13, use the crown block to pass through the furnace cover lifting ring 10, lift the furnace cover 11, pass the drawn wire 1 through the directional wheel 2, and then pass through the induction coil 4 and the guide wheel 6, and then pass out of the wire softening furnace into the next drawing;

[0048] ⑤ Close the furnace cover 11, close the furnace body by the fastening bolt 13 to ensure the sealing of the furnace;

[0049] ⑥ Pass the protective atmosphere 3-5 min through the gas protection device 13 to ensure the inert atmosphere in the furnace.

[0050] The above method is suitable for wires with a diameter of 1.9-2.1 mm. Example 1

[0051] The wire to be treated is a 2.0 mm diameter high-strength stainless steel wire. After the last drawing, the strength of the wire is 2070 MPa. The drawing process appears to be broken due to the high strength. The strength needs to be reduced to 680-720 MPa to meet the subsequent drawing and product strength requirements.

[0052] Refer to the attached Figure 1According to the production rhythm, the annealing time is determined as 10 min;

[0053] According to the material characteristics, the annealing temperature is determined as 1200℃;

[0054] In order to meet the subsequent drawing strength requirements, according to the formula: R=(642186*exp(-TEMP / 129.6)+637.9)*(0.01659*exp(-t / 6.9487)+0.9937)*(0.076*exp(-Z / 2.747)+0.998)

[0055] The required number of open coil groups is determined as 10 groups.

[0056] According to the calculated parameter values, the annealing furnace parameters are set, the protective atmosphere is introduced through the gas protection device 13 for 3 min, and the inert atmosphere in the furnace is ensured.

[0057] The strength of the annealed metal wire is 702 MPa, which meets the subsequent processing requirements. Example 2

[0058] The metal wire to be processed is a 1.9 mm diameter metal wire. After the last drawing, the strength of the metal wire is 2095 MPa. The strength needs to be reduced to 900-950 MPa to meet the subsequent drawing and finished product strength requirements.

[0059] Referring to the attached Figure 1 According to the production rhythm, the annealing time is determined as 5 min;

[0060] According to the material characteristics, the annealing temperature is determined as 1000℃;

[0061] In order to meet the subsequent drawing strength requirements, according to the formula: R=(642186*exp(-TEMP / 129.6)+637.9)*(0.01659*exp(-t / 6.9487)+0.9937)*(0.076*exp(-Z / 2.747)+0.998)

[0062] The required number of open coil groups is determined as 5 groups.

[0063] According to the calculated parameter values, the annealing furnace parameters are set, the protective atmosphere is introduced through the gas protection device 13 for 4 min, and the inert atmosphere in the furnace is ensured.

[0064] The strength of the annealed metal wire is 920 MPa, which meets the subsequent processing and finished product requirements. Example 3

[0065] The wire to be treated is a 2.1 mm diameter wire. After the previous drawing pass, the wire strength is 2003 MPa. The strength needs to be reduced to 1300-1350 MPa to meet the subsequent drawing and finished product strength requirements.

[0066] Referring to the attached drawings Figure 1 According to the production rhythm, the annealing time is determined to be 1 min;

[0067] According to the material properties, the annealing temperature is determined to be 900°C;

[0068] To meet the subsequent drawing strength requirements, according to the formula: R = (642186 x exp(-TEMP / 129.6) + 637.9) x (0.01659 x exp(-t / 6.9487) + 0.9937) x (0.076 x exp(-Z / 2.747) + 0.998)

[0069] The number of coil groups required to be opened is determined to be 2 groups.

[0070] According to the calculated parameter values, the annealing furnace parameters are set, the protective atmosphere is introduced through the gas protection device 13 for 5 min, and the inert atmosphere in the furnace is ensured.

[0071] The strength of the wire after annealing is 1310 MPa. It meets the subsequent processing and finished product requirements.

Claims

1. A method for softening of wire for continuous drawing, characterized in that: Operation is carried out according to the following steps: Step one: when the drawing strength of the drawn metal wire reaches 2000 MPa or more, the drawn metal wire is softened by using a metal wire softening furnace; the metal wire softening furnace comprises a furnace cover (11) and a furnace body (12), the furnace body (12) is rectangular, the furnace body (12) is provided with a metal wire inlet and a metal wire outlet on the corresponding two sides respectively, a positioning wheel (2) is arranged in the furnace body (12) near the metal wire inlet and the metal wire outlet respectively, a plurality of guide wheels (6) are arranged between the two positioning wheels (2), and the two positioning wheels (2) and the plurality of guide wheels (6) form an S-shaped metal wire in the furnace body (12), and the S-shaped metal wire passes through a plurality of groups of induction coils (4); Step two: when the drawn metal wire is softened, the softening furnace parameters are set according to the following formula according to the subsequent drawing strength requirements; R=(642186*exp(-TEMP / 129.6)+637.9)*(0.01659*exp(-t / 6.9487)+0.9937)*(0.076*exp(-Z / 2.747)+0.998) In the formula: R is the strength after annealing, unit: MPa; TEMP is the internal temperature of the softening furnace, unit: ℃; t is the residence time of the metal wire in the furnace, unit: min; Z is the number of groups of induction coils required to be opened, unit: group. When the drawn metal wire is softened, the gas protection device (3) is used to introduce a protective atmosphere into the softening furnace for 3-5 min to ensure the inert atmosphere in the furnace. The furnace body (12) is composed of a softening furnace outer steel plate outer wall (14), a middle layer of refractory brick layer (15) and an inner layer of refractory cotton layer (16). The furnace cover (11) is fixed on the furnace body (12) by high-temperature resistant bolts (13).

2. A method for softening of wire for continuous drawing according to claim 1, characterized in that: The furnace cover (11) is provided with a furnace cover lifting ring (10).

3. A method for softening of wire for continuous drawing according to claim 1, characterized in that: There are four guide wheels (6) between the two positioning wheels (2), one positioning wheel (2) and two guide wheels (6) constitute a row, and there are two rows in total.

4. A method for softening of wire for continuous drawing according to claim 3, characterized in that: The induction coil (4) through which the S-shaped metal wire passes is ten groups, and the ten groups of induction coils (4) are divided into two columns, five groups in each column.

5. A method for softening of wire for continuous drawing according to claim 4, characterized in that: The furnace body (12) is provided with a gas protection device (3) and a temperature measuring device (9).

6. A method for softening wire for continuous drawing according to claim 1, characterized in that: The diameter of the metal wire is 1.9-2.1 mm.

7. A method for softening of wire for continuous drawing as claimed in claim 3 wherein: ​ 8. A method for softening of wire for continuous drawing as claimed in claim 1 wherein: ​ 9. A method for softening of wire for continuous drawing as claimed in claim 1 wherein: ​

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