Production method of wire rod for welding wire and production method of welding wire

Abstract

The invention provides a production method of a steel wire rod and a welding wire, and the production method of the steel wire rod comprises the following working procedures sequentially performed on a square billet: a heating working procedure: the square billet sequentially passes through a preheating section, a heating section and a soaking section, the temperature of the preheating section is controlled to be 820-870 DEG C, the temperature of the heating section is controlled to be 950-1000 DEG C, the temperature of the soaking section is controlled to be 1000-1040 DEG C, and the total heating time is 70-90 minutes; in the rolling procedure, rough rolling, intermediate rolling and finish rolling are conducted on the heated square billet to obtain a wire rod, the finish rolling inlet temperature is controlled to be smaller than or equal to 850 DEG C, the rolling speed is controlled to be 100-110 m / s, and the spinning temperature is controlled to be 780-810 DEG C; and a cooling process: after spinning, controlling the cooling speed to be less than or equal to 0.6 DEG C / s, and cooling the wire rod to 500-550 DEG C. According to the production method of the steel wire rod, the steel wire rod has a small-size structure, drawing is facilitated, the mechanical property of the same circle is uniform, the thickness of the oxide layer is uniform, and shelling is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of steel smelting, and in particular to a method for producing a high-uniformity, low-spatter welding wire and a method for producing a wire rod for the welding wire. Background Art

[0002] During the production process, traditional welding wires (such as ER70S-6) often suffer from inadequate process control, leading to uneven material properties. This is manifested in significant fluctuations in tensile strength along the length (often exceeding 100 MPa), which can lead to problems such as poor wire feeding and arc stability. Furthermore, the oxide scale on the wire rod surface after rolling is difficult to completely remove, and the remaining dense oxide layer, such as Fe2SiO4, easily causes spatter during welding, with spatter rates generally exceeding 8%, severely impacting welding quality and the efficiency of automated equipment. Especially in high-precision applications such as robotic welding, these defects can lead to poor weld formation and frequent adjustments to process parameters, significantly increasing production costs. While existing technologies attempt to improve uniformity through annealing or adjusting the drawing process, annealing processes are costly, and conventional drawing with excessively high compression ratios (>10%) can lead to internal stress concentration in the material, further exacerbating performance fluctuations. Therefore, there is an urgent need for a welding wire and its preparation method that combines high uniformity with low spatter and is suitable for high-speed production. Summary of the Invention

[0003] The purpose of the present application is to provide a method for producing wire rods for welding wire, which solves the problem in the prior art that it is difficult to achieve high uniformity, low spatter and high-speed production at the same time.

[0004] In order to achieve one of the above-mentioned objects of the invention, an embodiment of the present application provides a method for producing a wire rod for welding wire, comprising the following steps performed sequentially on a square billet: In the heating process, the billet is sequentially passed through the preheating section, the heating section, and the soaking section. The temperature of the preheating section is controlled at 820-870°C, the temperature of the heating section is controlled at 950-1000°C, and the temperature of the soaking section is controlled at 1000-1040°C. The total heating time is 70-90 minutes. In the rolling process, the heated billet is subjected to rough rolling, intermediate rolling and finish rolling to obtain wire rod, and the finish rolling inlet temperature is controlled to be ≤850°C, the rolling speed is controlled to be 100-110m / s, and the spinning temperature is controlled to be 780-810°C; Cooling process: After spinning, control the cooling rate to ≤0.6℃ / s and cool the wire rod to 500~550℃.

[0005] In one embodiment of the present application, in the cooling process, after the wire rod is cooled to 500~550℃, it is sent to the insulation corridor to continue cooling to below 300℃, and the cooling rate of the wire rod in the insulation corridor is greater than the cooling rate of the wire rod before reaching 500~550℃ after spinning.

[0006] In one embodiment of the present application, after the wire rod is spun in the rolling process, the forward speed of the wire rod in the cooling process is 0.9 - 1.1 m / s, and the temperature difference within the same coil of the wire rod does not exceed 50 °C.

[0007] In one embodiment of the present application, the total thickness of the oxide layer on the surface of the wire rod is 5 - 10 μm, wherein the thickness of the FeO layer accounts for no less than 50% of the total thickness of the oxide layer.

[0008] In one embodiment of the present application, the tensile strength of the wire rod is 450 - 500 MPa, and the reduction of area ≥ 80%.

[0009] The present application also provides a method for producing a welding wire, including the following processes sequentially performed on a bloom, Heating process: passing the bloom through a preheating section, a heating section, and a soaking section in sequence, controlling the temperature of the preheating section to be 820 - 870 °C, the temperature of the heating section to be 950 - 1000 °C, the temperature of the soaking section to be 1000 - 1040 °C, and the total heating time to be 70 - 90 min; Rolling process: performing rough rolling, medium rolling, and finish rolling on the heated bloom to obtain a wire rod, controlling the finish rolling inlet temperature ≤ 850 °C, controlling the rolling speed to be 100 - 110 m / s, and controlling the spinning temperature to be 780 - 810 °C; Cooling process: after spinning, controlling the cooling rate ≤ 0.6 °C / s and cooling the wire rod to 500 - 550 °C; Drawing process: without performing heat treatment after cooling, directly drawing at a drawing speed ≥ 25 m / s, with the average reduction ratio of rough drawing ≤ 5% and the average reduction ratio of fine drawing ≤ 7%.

[0010] In one embodiment of the present application, after drawing the wire rod into a welding wire, a coating is applied to the surface of the welding wire. The components of the coating include, by mass percentage: 8 - 12% polyvinyl alcohol, 1 - 3% sodium polyacrylate, 2 - 4% nanocellulose, 1 - 3% sodium molybdate, 7 - 12% graphite, 5 - 8% graphene, and the balance is water.

[0011] In one embodiment of the present application, a weld metal test is performed on the welding wire, and the welding spatter rate is 2 - 5%.

[0012] In one embodiment of the present application, the tensile strength of the weld ≥ 430 MPa, the impact at -40 °C ≥ 100 J, and the difference in tensile strength within a 100 m length of the welding wire ≤ 30 MPa.

[0013] In one embodiment of the present application, the chemical composition of the weld metal, by mass percentage, includes: C: 0.05 - 0.07%, Si: 0.40 - 0.60%, Mn: 1.10 - 1.45%, Al ≤ 0.008%, Ca ≤ 0.0010%, Mg ≤ 0.0003%, Ti ≤ 0.003%, and the balance is iron and unavoidable impurities.

[0014] One or more technical solutions provided by the present application have at least the following technical effects or advantages: The production method of the wire rod for welding wire provided by the present application makes the austenite grains refined through gradient temperature-controlled heating, multi-pass rolling, and temperature-controlled cooling, so that the tissue size after rolling and cooling is smaller, which is beneficial for drawing; at the same time, it effectively reduces the thickness of the oxide layer, improves the mechanical properties of the same coil of the wire rod and the uniformity of the oxide layer thickness, makes the oxide layer easy to remove, and reduces the welding spatter rate. Specific embodiments

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. 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 protection scope of the present invention.

[0016] The embodiment of the present application provides a production method of a wire rod for welding wire, including the following processes sequentially performed on the bloom: Heating process: The bloom is sequentially passed through a preheating section, a heating section, and a soaking section, and the temperature of the preheating section is controlled at 820 - 870 °C, the temperature of the heating section is controlled at 950 - 1000 °C, the temperature of the soaking section is controlled at 1000 - 1040 °C, and the total heating time is 70 - 90 min; Rolling process: The heated bloom is subjected to rough rolling, medium rolling, and finish rolling to obtain a wire rod. The finish rolling inlet temperature is controlled ≤ 850 °C, the rolling speed is controlled at 100 - 110 m / s, and the laying head temperature is controlled at 780 - 810 °C; Cooling process: After laying head, the cooling speed is controlled ≤ 0.6 °C / s, and the wire rod is cooled to 500 - 550 °C.

[0017] Heating ensures the homogenization of austenite and reduces grain boundary segregation; at the same time, it avoids the formation of martensite during cooling due to coarse austenite, resulting in wire breakage during the drawing process. Controlling a lower finish rolling inlet temperature can refine the grains and improve the surface quality, and controlling a reasonable rolling speed makes the structure of the core and surface of the bloom uniform.

[0018] After rolling is completed, wire is formed by laying, and the laying temperature is controlled so that the shape of the wire coils is uniform. The cooling rate is coordinated to ensure that the wire exits cooling at the aforementioned final cooling temperature (500 - 550°C) at this cooling rate, allowing sufficient time for the austenite to undergo phase transformation, and avoiding too high a final cooling temperature, which would cause the cooling rate to increase after exiting cooling and prevent the austenite from having enough time to transform into martensite.

[0019] Cooling is carried out using a Stelmor cooling line. All the insulating covers of the Stelmor cooling line are closed to control a slower cooling rate.

[0020] After Stelmor cooling, the wire is coiled and sent into a heat-insulating corridor for continued cooling. Since the space in the heat-insulating corridor is much larger than the space inside the insulating cover on the Stelmor cooling line, the cooling rate of the wire in the heat-insulating corridor is greater than that on the Stelmor cooling line, approximately 2 - 3°C / s, and the temperature of the wire is reduced to below 300°C in the heat-insulating corridor.

[0021] Through the coordination of the aforementioned rolling speed and laying temperature, the generation thickness of the oxide layer can be effectively reduced, and at the same time, the mechanical properties of the wire within the same coil and the uniformity of the oxide layer thickness are improved.

[0022] In an embodiment of the present application, the bloom is subjected to 6 passes of rough rolling, 6 passes of medium rolling, 4 passes of pre-finishing rolling, and 10 passes of finishing rolling.

[0023] Further, after laying in the rolling process, the forward speed of the wire is 0.9 - 1.1 m / s, and the temperature difference within the same coil of the wire does not exceed 50°C.

[0024] The Stelmor cooling line has a certain length. The speed of the roller table of the Stelmor cooling line, that is, the forward speed of the wire, is controlled to ensure the cooling rate and final cooling temperature of the wire. After rolling and laying, the wire forms into layers of coils one by one and advances driven by the roller table of the Stelmor cooling line. Controlling the temperature difference within the same coil of the wire can make the wire uniform and avoid a large difference in the structure between the front and back of the wire.

[0025] In an embodiment of the present application, the total thickness of the oxide layer on the surface of the wire is 5 - 10 μm, and among them, the thickness of the FeO layer accounts for no less than 50% of the total thickness of the oxide layer.

[0026] The total thickness of the oxide layer is relatively low, which is conducive to peeling. When removing the oxide layer by shelling, since the thickness of the FeO layer accounts for a relatively large proportion of the total thickness of the oxide layer, the Fe₂SiO₄ between the FeO layer and the wire matrix can be peeled off together with the FeO.

[0027] In an embodiment of the present application, the tensile strength of the wire is 450 - 500 MPa, and the reduction of area ≥ 80%.

[0028] The present application also provides a method for producing welding wire, including the following processes sequentially carried out on the bloom Heating process: The square billet is successively passed through the preheating section, heating section, and soaking section. The temperature of the preheating section is controlled at 820 - 870 °C, the temperature of the heating section is controlled at 950 - 1000 °C, the temperature of the soaking section is controlled at 1000 - 1040 °C, and the total heating time is 70 - 90 min; Rolling process: The heated square billet is rough rolled, medium rolled, and finish rolled to obtain wire rods. The temperature at the entrance of the finish rolling is controlled ≤ 850 °C, the rolling speed is controlled at 100 - 110 m / s, and the spinning temperature is controlled at 780 - 810 °C; Cooling process: After spinning, the cooling speed is controlled ≤ 0.6 °C / s, and the wire rods are cooled to 500 - 550 °C; Drawing process: After cooling, no heat treatment is carried out. The drawing speed is controlled ≥ 25 m / s for direct drawing. The average reduction ratio of rough drawing is ≤ 5%, and the average reduction ratio of fine drawing is ≤ 7%.

[0029] The production method of this welding wire is obtained by drawing the wire rods obtained from the production method of the aforementioned wire rods. Therefore, the heating, rolling, and cooling processes are the same as those in the production method of the wire rods for the aforementioned welding wire.

[0030] The wire rods are directly and rapidly drawn without heat treatment to avoid grain coarsening caused by heat treatment such as annealing. Through multiple passes of rough drawing and fine drawing, a lower reduction ratio is controlled to make the welding wire more uniform.

[0031] Furthermore, before drawing, a two-way peeling wheel combined with two passes of sand belt grinding is used to remove the oxide scale, reducing the welding spatter problem caused by incomplete removal of the oxide scale.

[0032] In an embodiment of the present application, after the wire rods are drawn into welding wires, a coating is applied to the surface of the welding wires. The components of the coating include, by mass percentage: polyvinyl alcohol 8 - 12%, sodium polyacrylate 1 - 3%, nanocellulose 2 - 4%, sodium molybdate 1 - 3%, graphite 7 - 12%, graphene 5 - 8%, and the balance is water.

[0033] Polyvinyl alcohol + sodium polyacrylate + nanocellulose fiber are used as the bonding matrix, and sodium molybdate, graphite, and graphene are added to improve lubricity and conductivity, further reducing spatter.

[0034] In an embodiment of the present application, a deposited metal test is carried out on the welding wire, and the welding spatter rate is 2 - 5%. The deposited metal test is carried out with reference to the standard GB∕T 39281 - 2020. After each pass of welding is completed, the metal spatter particles around the weld are collected, and the weight A (kg) is measured. The welding consumables consumed during the welding process are B (kg). The spatter rate calculation formula = A / B × 100%. It should be noted that during welding, a baffle is used to shield the periphery of the weld to prevent the metal spatter particles from splashing too far and being missed in collection, resulting in a lower calculated welding spatter rate.

[0035] Furthermore, the tensile strength of the weld seam is ≥ 430 MPa, the impact at -40 °C is ≥ 100 J, the difference in tensile strength within a 100 m length of the welding wire is ≤ 30 MPa, the uniformity of the welding wire is improved by more than 3 times compared with ER70S-6, the wire feeding stability is excellent, the welding arc is continuously stable, the spatter rate is significantly reduced (≤ 5%), the slag stripping property is good, and it is especially suitable for fields with strict requirements for process consistency such as robotic automated welding.

[0036] In an embodiment of the present application, the chemical components of the wire rod and the welding wire include, by mass percentage: C: 0.05 - 0.07%, Si: 0.50 - 0.70%, Mn: 1.0 - 1.7%, Al ≤ 0.008%, Ca ≤ 0.0010%, Mg ≤ 0.0003%, Ti ≤ 0.003%, and the balance is iron and inevitable impurities.

[0037] In an embodiment of the present application, the chemical components of the weld metal include, by mass percentage: C: 0.05 - 0.07%, Si: 0.40 - 0.60%, Mn: 1.10 - 1.45%, Al ≤ 0.008%, Ca ≤ 0.0010%, Mg ≤ 0.0003%, Ti ≤ 0.003%, and the balance is iron and inevitable impurities.

[0038] The technical solution of the present application will be further described below in conjunction with some specific embodiments.

[0039] Example 1 Heating: The square billet is successively passed through a preheating section (820 °C), a heating section (950 °C), and a soaking section (1000 °C), with a total heating time of 70 minutes.

[0040] Rolling: The square billet is subjected to 6 passes of rough rolling, 6 passes of medium rolling, 4 passes of pre-finishing rolling, and 10 passes of finishing rolling (the finishing rolling inlet temperature is 850 °C), and finally a φ5.5 mm wire rod is formed. The rolling speed is 100 m / s, and the laying temperature is 780 °C.

[0041] Cooling: The roller table speed of the Stelmor cooling line is 0.9 m / s, and it is cooled at a cooling rate of 0.6 °C / s to 500 °C, and then coiled and enters the heat preservation corridor for cooling to 250 °C. After cooling, the tensile strength of the wire rod is 450 MPa, the reduction of area is 80%, and the total thickness of the oxide layer is 5 μm (the FeO layer accounts for 50%).

[0042] Surface treatment: Two-way shelling wheel treatment is combined with 2 passes of sand belt grinding to thoroughly remove the oxide scale.

[0043] Drawing: Non-annealing drawing is carried out at a speed of 25 m / s. The average reduction ratio of rough drawing is 4%, and the average reduction ratio of fine drawing is 6%.

[0044] Coating preparation: Prepare the coating solution according to mass percentages (8% polyvinyl alcohol, 1% sodium polyacrylate, 2% nanocellulose fiber, 1% sodium molybdate, 7% graphite, 5% graphene, with the balance being water), and evenly coat it on the surface of the welding wire.

[0045] Example 2 Heating: Pass the bloom through the preheating section (850 °C), heating section (980 °C), and soaking section (1030 °C) in sequence, with a total heating time of 80 minutes.

[0046] Rolling: The entry temperature of the finishing mill is 840 °C, the rolling speed is 105 m / s, and the coiling temperature is 800 °C. The distribution of the remaining passes is the same as in Example 1.

[0047] Cooling: The roller table speed of the Stelmor cooling line is 1.0 m / s, and it is cooled at a cooling rate of 0.5 °C / s to 530 °C, and then coiled and sent into the heat preservation corridor for cooling to 280 °C. After cooling, the tensile strength of the wire rod is 470 MPa, the reduction of area is 85%, and the total thickness of the oxide layer is 5 μm (the FeO layer accounts for 50%).

[0048] Surface treatment: After treatment with a two-way peeling wheel, perform 2 passes of abrasive belt grinding to ensure that the oxide scale removal rate is ≥99%.

[0049] Drawing: Drawing without annealing, at a speed of 28 m / s, with an average reduction ratio of 3% for rough drawing and 5% for fine drawing.

[0050] Coating preparation: Prepare the coating solution according to mass percentages (10% polyvinyl alcohol, 2% sodium polyacrylate, 3% nanocellulose fiber, 2% sodium molybdate, 10% graphite, 7% graphene, with the balance being water), and evenly coat it on the surface of the welding wire.

[0051] Example 3 Heating: Pass the bloom through the preheating section (870 °C), heating section (1000 °C), and soaking section (1040 °C) in sequence, with a total heating time of 90 minutes.

[0052] Rolling: The entry temperature of the finishing mill is 820 °C, the rolling speed is 110 m / s, and the coiling temperature is 810 °C. The distribution of the remaining passes is the same as in Example 1.

[0053] Cooling: The roller table speed of the Stelmor cooling line is 1.1 m / s, and it is cooled at a cooling rate of 0.4 °C / s to 550 °C, and then coiled and sent into the heat preservation corridor for cooling to 300 °C. After cooling, the tensile strength of the wire rod is 505 MPa, the reduction of area is 82%, and the total thickness of the oxide layer is 10 μm (the FeO layer accounts for 60%).

[0054] Surface treatment: After treatment with a two-way peeling wheel, perform 2 passes of abrasive belt grinding to ensure that the surface roughness is ≤0.5 μm.

[0055] Drawing: Annealing-free drawing at a speed of 30 m / s, with an average reduction ratio of 5% for rough drawing and 7% for fine drawing.

[0056] Coating preparation: Prepare the coating solution according to mass percentage (12% polyvinyl alcohol, 3% sodium polyacrylate, 4% nanofibrillated cellulose, 3% sodium molybdate, 12% graphite, 8% graphene, and the balance is water), and uniformly coat it on the surface of the welding wire.

[0057] Example 4 Heating: Pass the bloom through the preheating section (830 °C), heating section (960 °C), and soaking section (1020 °C) in sequence, with a total heating time of 75 minutes.

[0058] Rolling: The entry temperature of finish rolling is 830 °C, the rolling speed is 108 m / s, and the laying temperature is 790 °C. The distribution of the remaining passes is the same as that in Example 1.

[0059] Cooling: The roller table speed of the Stelmor cooling line is 1.0 m / s, and it is cooled at a cooling rate of 0.55 °C / s to 520 °C, and then coiled and enters the heat preservation corridor for cooling to 270 °C. After cooling, the tensile strength of the wire rod is 490 MPa, the reduction of area is 80%, and the total thickness of the oxide layer is 7 μm (the proportion of the FeO layer is 52%).

[0060] Surface treatment: After treatment with a two-way peeling wheel, two passes of sand belt grinding are carried out to improve the surface finish in combination with sand belt grinding.

[0061] Drawing: Annealing-free drawing at a speed of 26 m / s, with an average reduction ratio of 4.5% for rough drawing and 6.5% for fine drawing.

[0062] Coating preparation: Prepare the coating solution according to mass percentage (9% polyvinyl alcohol, 1.5% sodium polyacrylate, 2.5% nanofibrillated cellulose, 1.5% sodium molybdate, 9% graphite, 6% graphene, and the balance is water), and uniformly coat it on the surface of the welding wire.

[0063] Example 5 Heating: Pass the bloom through the preheating section (840 °C), heating section (990 °C), and soaking section (1035 °C) in sequence, with a total heating time of 85 minutes.

[0064] Rolling: The entry temperature of finish rolling is 845 °C, the rolling speed is 107 m / s, and the laying temperature is 805 °C. The distribution of the remaining passes is the same as that in Example 1.

[0065] Cooling: The roller table speed of the Stelmor cooling line is 1.05 m / s, and it is cooled at a cooling rate of 0.45 °C / s to 540 °C, and then coiled and enters the heat preservation corridor for cooling to 290 °C. After cooling, the tensile strength of the wire rod is 484 MPa, the reduction of area is 83%, and the total thickness of the oxide layer is 9 μm (the proportion of the FeO layer is 58%).

[0066] Surface treatment: After being processed by a two-way peeling wheel, it undergoes two passes of abrasive belt grinding, combined with high-precision abrasive belt grinding.

[0067] Drawing: Non-annealed drawing is carried out at a speed of 27 m / s. The average compression ratio for rough drawing is 4.8%, and the average compression ratio for fine drawing is 6.8%.

[0068] Coating preparation: Prepare the coating solution according to mass percentages (11% polyvinyl alcohol, 2.5% sodium polyacrylate, 3.5% nanofibrillated cellulose, 2.5% sodium molybdate, 11% graphite, 7.5% graphene, and the balance is water), and evenly coat it on the surface of the welding wire.

[0069] The welding wires obtained in Examples 1 to 5 were subjected to a deposited metal test and mechanical property detection with reference to Standard GB∕T 39281-2020. The welding current was 300 ± 30 A, the voltage was 29 ± 2 V, and the heat input during welding was 13 kJ / cm. The composition of the deposited metal was tested using an ICP and a CS instrument. The results are shown in Table 1, and the mechanical properties are shown in Table 2. For each finished welding wire of each example, 100 m of continuous wire was randomly selected and divided into 400 tensile specimens, each with a length of 0.25 m. Then, the maximum tensile strength Rm max and the minimum tensile strength Rm min were statistically analyzed, and the difference △Rm = Rm max - Rm min was calculated.

[0070] After each pass of welding was completed, the metal splash particles around the weld were collected and the weight A (kg) was measured. The welding materials consumed during the welding process were B (kg). The splash rate calculation formula = A / B × 100%. The statistical results of the splash rate and the mechanical property test results are shown in Table 2.

[0071] Table 1 Chemical components of Examples 1 to 5 (%)

[0072] Table 2 Splash rate, mechanical properties, and uniformity of Examples 1 to 5

[0073] It should be understood that although this specification is described according to embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0074] The series of detailed descriptions listed above are only specific descriptions of the feasible implementation manners of this application, and they are not intended to limit the protection scope of this application. Any equivalent implementation manners or modifications made without departing from the technical spirit of this application shall be included within the protection scope of this application.

Claims

1. A production method of wire rod for welding wire, characterized in that, It includes the following processes carried out on the bloom in sequence, Heating process: The bloom is passed through the preheating section, heating section, and soaking section in sequence. The temperature of the preheating section is controlled at 820 - 870 °C, the temperature of the heating section is controlled at 950 - 1000 °C, the temperature of the soaking section is controlled at 1000 - 1040 °C, and the total heating time is 70 - 90 min; Rolling process: The heated bloom is rough-rolled, medium-rolled, and finish-rolled to obtain wire rods. The temperature at the entrance of the finish rolling is controlled ≤ 850 °C, the rolling speed is controlled at 100 - 110 m / s, and the spinning temperature is controlled at 780 - 810 °C; Cooling process: After spinning, the cooling speed is controlled ≤ 0.6 °C / s, and the wire rods are cooled to 500 - 550 °C.

2. The production method of the wire rod for welding wire according to claim 1, characterized in that, In the cooling process, after the wire rods are cooled to 500 - 550 °C, they are sent to the heat preservation corridor and continue to be cooled to below 300 °C. The cooling speed of the wire rods in the heat preservation corridor > the cooling speed of the wire rods before reaching 500 - 550 °C after spinning.

3. The production method of the wire rod for welding wire according to claim 2, characterized in that, After spinning in the rolling process, the forward speed of the wire rods in the cooling process is 0.9 - 1.1 m / s, and the temperature difference within the same coil of the wire rods does not exceed 50 °C.

4. The production method of the wire rod for welding wire according to claim 2, characterized in that, The total thickness of the oxide layer on the surface of the wire rods is 5 - 10 μm. Among them, the thickness of the FeO layer accounts for no less than 50% of the total thickness of the oxide layer.

5. The production method of the wire rod for welding wire according to claim 1, characterized in that, The tensile strength of the wire rods is 450 - 500 MPa, and the reduction of area ≥ 80%.

6. A production method of a welding wire, characterized in that, It includes the following processes carried out on the bloom in sequence, Heating process: The bloom is passed through the preheating section, heating section, and soaking section in sequence. The temperature of the preheating section is controlled at 820 - 870 °C, the temperature of the heating section is controlled at 950 - 1000 °C, the temperature of the soaking section is controlled at 1000 - 1040 °C, and the total heating time is 70 - 90 min; Rolling process: The heated bloom is rough-rolled, medium-rolled, and finish-rolled to obtain wire rods. The temperature at the entrance of the finish rolling is controlled ≤ 850 °C, the rolling speed is controlled at 100 - 110 m / s, and the spinning temperature is controlled at 780 - 810 °C; Cooling process: After spinning, the cooling speed is controlled ≤ 0.6 °C / s, and the wire rods are cooled to 500 - 550 °C; Drawing process: After cooling, no heat treatment is carried out. The drawing speed is controlled ≥ 25 m / s for direct drawing, the average reduction ratio of rough drawing ≤ 5%, and the average reduction ratio of fine drawing ≤ 7%.

7. The production method of the welding wire according to claim 6, characterized in that, After the wire rods are drawn into welding wires, a coating is applied on the surface of the welding wires. The components of the coating include, by mass percentage: polyvinyl alcohol 8 - 12%, sodium polyacrylate 1 - 3%, nanocellulose 2 - 4%, sodium molybdate 1 - 3%, graphite 7 - 12%, graphene 5 - 8%, and the balance is water.

8. The production method of the welding wire according to claim 6, characterized in that, A deposited metal test is carried out on the welding wires, and the welding spatter rate is 2 - 5%.

9. The production method of the welding wire according to claim 8, characterized in that, The tensile strength of the weld ≥ 430 MPa, the impact at - 40 °C ≥ 100 J, and the difference in tensile strength within the range of 100 m length of the welding wires ≤ 30 MPa.

10. The production method of the welding wire according to claim 8, characterized in that, The chemical composition of the weld metal includes, by mass percentage: C: 0.05 - 0.07%, Si: 0.40 - 0.60%, Mn: 1.10 - 1.45%, Al ≤ 0.008%, Ca ≤ 0.0010%, Mg ≤ 0.0003%, Ti ≤ z0.003%, and the rest is iron and inevitable impurities.

Images