A continuous annealing production method for an extra thin gauge flux cored wire steel

Abstract

The application discloses a continuous annealing production method for an extremely thin specification flux-cored wire steel, and discloses control processes and control parameters of each working procedure of the continuous annealing production method. The continuous annealing production method for the extremely thin specification flux-cored wire steel is realized through the process control, the stable and smooth production line can be ensured, and production accidents can be avoided.

Description

Technical Field

[0001] This invention relates to the field of heat treatment technology for materials, and in particular to a continuous annealing production method for steel used in ultra-thin flux-cored welding wire. Background Technology

[0002] The smaller the diameter of the flux-cored welding wire, the better its penetration, which helps control the welding depth. Smaller diameter flux-cored welding wires are mainly used for welding thin plates and have a wide range of applications. To meet the application requirements of small-diameter flux-cored welding wires, steel mills need to develop thinner special steel strips for welding wires, with a thickness range of 0.30-0.35mm. This specification poses challenges to the heat treatment of the production line, with risks of furnace warping, strip breakage, and wrinkling. It is necessary to conduct necessary inspections of the production line and reasonably control factors such as annealing temperature, production line speed, and looper quantity. This invention provides a continuous annealing production method for ultra-thin low-carbon flux-cored welding wire steel to ensure stable and smooth operation of the production line and avoid production accidents. Summary of the Invention

[0003] Continuous annealing of steel with a diameter of 0.3 to 0.35 mm is difficult and can easily lead to risks such as warping, breakage, and wrinkling in the furnace area. The purpose of this invention is to provide a continuous annealing production method for steel with an ultra-thin diameter flux-cored welding wire, which can ensure the stable and smooth operation of the production line and avoid production accidents.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] This invention discloses a continuous annealing production method for steel used in ultra-thin flux-cored welding wire, comprising:

[0006] (1) Before annealing, the cold-rolled strip steel is inspected with a surface inspection instrument. The surface is not allowed to have serious oxides, inclusions, glaze marks, holes, edge cracks or serrated edge defects. The middle waviness shall not be greater than 50 I-Units and the edge waviness shall not be greater than 100 I-Units. Steel strips with such defects shall be returned in time.

[0007] (2) Check the number of welding cycles of the welding wheel, and replace and grind it in time when the replacement cycle is reached; use narrow lap welding, with thickness transitions of 0.45mm, 0.4mm, 0.35mm, and 0.3mm, and welding speed of 8-12m / min;

[0008] (3) The inlet looper volume should be maintained at 60%-80%, and the filling speed should be ≤200m / min;

[0009] (4) The outlet temperature of the heating section and the soaking section is 730-750℃, and the furnace speed is 115-145m / min;

[0010] (5) The amount of looper used for export should be maintained at 10%-20%, and the filling speed should be 115-145m / min;

[0011] (6) The elongation of the leveling machine is 0.045%-0.055%, the rolling force of the leveling machine is controlled at 1500-3000KN, and the speed of the leveling machine is ≤200m / min;

[0012] (7) Inspect the blades of the disc shears and replace any defective blades in a timely manner. The cutting edge amount on the drive side and the operating side should be controlled at 7-10mm.

[0013] (8) Place the paper sleeve on the winding mandrel, the same width as the steel strip, such as... Figure 1 As shown, after the steel coil is wound and slit, it is placed in a paper sleeve for winding again.

[0014] Furthermore, the paper sleeve has a diameter of 610 mm and a wall thickness of 20 mm.

[0015] Furthermore, the annealing process for steel used in ultra-thin 0.3-0.35mm low-carbon flux-cored welding wire is stabilized and runs smoothly.

[0016] Furthermore, the steel strip is welded to 0.45mm and 0.4mm flux-cored welding wires at a welding speed of 10m / min; the inlet looper fills 70%-80% of the material, with a filling speed of 80-200m / min; the outlet temperature of the heating and soaking sections is controlled at 745-750℃, with a furnace speed of 120-130m / min; the outlet looper fills 10% of the material, with a punching speed of 120-130m / min; the leveler elongation is 0.5%, the rolling force is 1886-2815KN, and the leveler speed is 20-200m / min; the disc shearing edge is 7-8mm; there is no wire jamming during the steel strip production process; and the paper sleeve width is 1160mm. The finished product has a yield strength of 175MPa, a tensile strength of 311MPa, an elongation of 47.0%, and exhibits good drawing performance.

[0017] Furthermore, the steel strip is welded to 0.35mm flux-cored welding wire at a welding speed of 11m / min; the inlet looper fills 70%-80% of the material, with a filling speed of 60-180m / min; the outlet temperature of the heating and soaking sections is controlled at 735-740℃, with a furnace speed of 130-145m / min; the outlet looper fills 10% of the material, with a punching speed of 120-130m / min; the leveler elongation is 0.5%, the rolling force is 1957-3000KN, and the leveler speed is 20-180m / min; the disc shearing edge is 9mm; there is no wire jamming during the steel strip production process; and the paper sleeve width is 1160mm. The finished product has a yield strength of 199MPa, a tensile strength of 321MPa, an elongation of 46.5%, and exhibits good drawing performance.

[0018] Furthermore, the steel strip is welded to 0.35mm flux-cored welding wire at a welding speed of 12m / min; the inlet looper fills 70%-80% of the material, with a filling speed of 60-180m / min; the outlet temperature of the heating and soaking sections is controlled at 730℃, with a furnace speed of 115m / min; the outlet looper fills 10% of the material, with a punching speed of 115m / min; the leveler elongation is 0.5%, the rolling force is 1675-2881KN, and the leveler speed is 20-180m / min; the disc shearing margin is 10mm; there is no wire jamming during the steel strip production process; and the paper sleeve width is 1160mm. The finished product has a yield strength of 203MPa, a tensile strength of 327MPa, an elongation of 45.5%, and exhibits good drawing performance.

[0019] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0020] The beneficial effect of this invention is that it achieves stable and smooth annealing of steel for ultra-thin 0.3-0.35mm low-carbon flux-cored welding wire through standardized operation and process design, thus avoiding production accidents. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] Figure 1 It is a paper sleeve photograph. Detailed Implementation

[0023] A method for continuous annealing of steel for ultra-thin flux-cored welding wire, comprising:

[0024] (1) Since the steel strip is thin, surface defects or plate defects can easily lead to accidents in the furnace area. Therefore, before annealing, the cold-rolled strip is inspected with a surface inspection instrument. The surface is not allowed to have serious oxides, inclusions, dents, holes, edge cracks or serrated edge defects. The middle waviness should not be greater than 50 I-Units and the edge waviness should be greater than 100 I-Units. Steel strips with such defects should be returned in time.

[0025] (2) Welding quality is the foundation for ensuring continuous production of steel strip. A detailed inspection of the welding process is necessary, including checking the number of welds made by the welding wheel and replacing and grinding it promptly when the replacement cycle is reached. The steel strip specifications are 0.3–0.35 mm, requiring transition materials of the same width, gradually transitioning from a thickness of 0.45 mm to 0.3 mm. The transition material specifications are 0.45 mm, 0.4 mm, 0.35 mm, and 0.3 mm respectively. Narrow lap welding should be performed at a medium speed of 8–12 m / min.

[0026] (3) The inlet looper serves to store steel strip and can coordinate continuous production between the furnace area and welding. If welding fails, it can still ensure that the strip steel runs normally in the furnace area for a short time. Therefore, the looper should be kept in full at all times, with the looper capacity maintained at 60% to 80%. The filling speed should be moderate to achieve the purpose of stable operation of the strip steel. The filling speed should be ≤200m / min.

[0027] (4) In the continuous annealing furnace zone, the strip heated in the preheating section enters the radiant tube heating furnace and the soaking furnace. All furnace chambers are filled with a nitrogen-hydrogen mixture to prevent the strip from oxidizing inside the furnace. Radiant tube heating mainly involves the combustion of fuel gas inside the radiant tubes, which heats the tubes themselves. The radiant tubes use thermal radiation to heat the strip to the predetermined annealing temperature and maintain it in the soaking furnace for a period of time to achieve the annealing purpose. To prevent the strip from wrinkling or even breaking in the furnace, the furnace zone temperature should not be too high and the speed should not be too fast. The outlet temperature of the heating section and the soaking section should be controlled at 730-750℃, and the furnace zone speed should be 115-145m / min.

[0028] (5) During normal production, the outlet looper is kept in an empty state with a looping amount of 10% to 20% to ensure that there is enough time for the outlet winding and cutting process, and the filling speed is kept stable at 115 to 145 m / min.

[0029] (6) Excessive rolling pressure causes waviness, while insufficient pressure easily produces feather marks. The rolling force should be mainly to meet the elongation requirement, so that the strip steel can obtain good shape and surface quality, as well as good mechanical properties. For steel used for flux-cored welding wire with specifications of 0.3~0.35mm, the elongation of the leveling machine should be 0.045~0.055%, the rolling force of the leveling machine should be controlled at 1500~3000KN, and the leveling machine speed should be ≤200m / min.

[0030] (7) The transverse position of the cutter head is adjusted by a controlled AC motor to achieve the required strip width. Before switching strip width, the weld seam must be punched at the crescent-shaped cutter in front of the disc shear. Inspect the disc shear blades and replace any defective blades promptly. When changing blades, the rotary table must be moved to the offline position before rotating to change blades. After changing blades, re-enter the line to reach the set value. When maintaining or replacing a cutter head in standby mode, the operator must lock the cutter head on the control panel to ensure safety. Observe the strip width at the leveler exit at all times. The cutting edge amount on the drive side and the operating side should be controlled between 7 and 10 mm to prevent the strip from narrowing and causing wire jamming.

[0031] (8) Due to the thinness of the strip steel, the core is prone to collapse after the steel coil is cut. Therefore, a paper sleeve with a diameter of 610mm, a wall thickness of 20mm, and the same width as the steel strip is first placed on the winding mandrel. Figure 1 As shown, after the steel coil is wound and slit, it is placed in a paper sleeve for winding again.

[0032] Example 1

[0033] Composition by weight percentage: [C]: 0.019%; [Si]: 0.004%; [Mn]: 0.24%; [P]: 0.009%; [S]: 0.005%; [Al]: 0.032%; [N]: 0.0023%, balance being Fe and impurities.

[0034] The finished steel for flux-cored welding wire has a specification of 0.35×1160mm. The raw material surface is free of oxides, inclusions, dents, holes, edge cracks, or serrated edge defects, and there are no central or edge wavinesses. The steel strip is welded to 0.45mm and 0.4mm flux-cored welding wire steel at a welding speed of 10m / min. The inlet looper fills 70%–80% of the area, with a filling speed of 80–200m / min. The outlet temperature of the heating and soaking sections is controlled at 745–750℃, and the furnace speed is 120–130m / min. The outlet looper fills 10% of the area, with a punching speed of 120–130m / min. The leveler has an elongation of 0.5%, a rolling force of 1886–2815KN, and a leveler speed of 20–200m / min. The disc shearing edge is 7–8mm. There is no wire jamming during the steel strip production process, and the paper sleeve width is 1160mm. The finished product has a yield strength of 175 MPa, a tensile strength of 311 MPa, and an elongation of 47.0%, and the product exhibits good drawing performance.

[0035] Example 2

[0036] Composition by weight percentage: [C]: 0.019%; [Si]: 0.005%; [Mn]: 0.25%; [P]: 0.008%; [S]: 0.006%; [Al]: 0.031%; [N]: 0.0012%, balance being Fe and impurities.

[0037] The finished steel for flux-cored welding wire has a specification of 0.30×1160mm. The raw material surface is free of oxides, inclusions, dents, holes, edge cracks, or serrated edge defects, and there are no central or edge wavinesses. The steel strip is welded to the 0.35mm flux-cored welding wire steel at a welding speed of 11m / min. The inlet looper fill weight is 70%–80%, and the filling speed is 60–180m / min. The outlet temperature of the heating and soaking sections is controlled at 735–740℃, and the furnace speed is 130–145m / min. The outlet looper fill weight is 10%, and the filling speed is 120–130m / min. The leveling mill has an elongation of 0.5%, a rolling force of 1957–3000KN, and a leveling mill speed of 20–180m / min. The disc shearing edge allowance is 9mm. There is no wire jamming during the steel strip production process, and the paper sleeve width is 1160mm. The finished product has a yield strength of 199 MPa, a tensile strength of 321 MPa, and an elongation of 46.5%, and the product exhibits good drawing performance.

[0038] Example 3

[0039] Composition by weight percentage: [C]: 0.018%; [Si]: 0.004%; [Mn]: 0.21%; [P]: 0.010%; [S]: 0.005%; [Al]: 0.029%; [N]: 0.0014%, balance being Fe and impurities.

[0040] The finished steel for flux-cored welding wire has a specification of 0.30×1160mm. The raw material surface is free of oxides, inclusions, dents, holes, edge cracks, or serrated edge defects, and there are no central or edge wavinesses. The steel strip is welded to the 0.35mm flux-cored welding wire steel at a welding speed of 12m / min. The inlet looper fills 70%–80% of the area, with a filling speed of 60–180m / min. The outlet temperature of the heating and soaking sections is controlled at 730℃, and the furnace speed is 115m / min. The outlet looper fills 10% of the area, with a punching speed of 115m / min. The leveling mill has an elongation of 0.5%, a rolling force of 1675–2881KN, and a leveling mill speed of 20–180m / min. The disc shearing edge allowance is 10mm. There is no wire jamming during the steel strip production process, and the paper sleeve width is 1160mm. The finished product has a yield strength of 203 MPa, a tensile strength of 327 MPa, and an elongation of 45.5%, and the product exhibits good drawing performance.

[0041] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for continuous annealing of steel for ultra-thin flux-cored welding wire, characterized in that, include: (1) Before annealing, the cold-rolled strip steel is inspected with a surface inspection instrument. The surface is not allowed to have serious oxides, inclusions, glaze marks, holes, edge cracks or serrated edge defects. The middle waviness shall not be greater than 50 I-Units and the edge waviness shall not be greater than 100 I-Units. Steel strips with such defects shall be returned in time. (2) Check the number of welding cycles of the welding wheel, and replace and grind it in time when the replacement cycle is reached; use narrow lap welding, with thickness transitions of 0.45mm, 0.4mm, 0.35mm, and 0.3mm, and welding speed of 8-12m / min; (3) The inlet looper volume should be maintained at 60%-80%, and the filling speed should be ≤200m / min; (4) The outlet temperature of the heating section and the soaking section is 730-750℃, and the furnace speed is 115-145m / min; (5) The amount of looper used for export should be maintained at 10%-20%, and the filling speed should be 115-145 m / min; (6) The elongation of the leveling machine is 0.045%-0.055%, the rolling force of the leveling machine is controlled at 1500-3000KN, and the speed of the leveling machine is ≤200m / min; (7) Inspect the blades of the disc shears and replace any defective blades in a timely manner. The cutting edge amount on the drive side and the operating side should be controlled at 7-10mm. (8) Place the paper sleeve on the winding mandrel, which is the same width as the steel strip. After the steel coil is wound and cut, place the paper sleeve again for winding.

2. The continuous annealing production method for ultra-thin flux-cored welding wire steel according to claim 1, characterized in that, The paper sleeve has a diameter of 610 mm and a wall thickness of 20 mm.

3. The continuous annealing production method for ultra-thin flux-cored welding wire steel according to claim 1, characterized in that, Achieve stable and smooth annealing process for steel used in ultra-thin 0.3-0.35mm low-carbon flux-cored welding wire.

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