Self-protection flux-cored wire and production method thereof

Abstract

The invention discloses a self-protection flux-cored wire and a production method thereof. The preparation method of the self-protection flux-cored wire comprises the following steps of S1, material treatment, S2, machining and treatment, S3, quality detection and S4, packaging and transportation. According to the target performance of the welding wire, a powder formula is elaborately designed, and the formula generally comprises a slag former for forming slag, protecting a molten pool, controlling metallurgical reaction of the molten pool and improving welding seam forming, a deoxidizer for removing oxygen and nitrogen in the molten pool and preventing pores and embrittlement, and a gas-making agent for generating protective gas through thermal decomposition, a gas hood is formed at the end of the flux-cored wire to isolate air, alloy elements are added into deposited metal to achieve required chemical components and performance, an arc stabilizer is used for improving arc stability, and a small amount of binder is added sometimes to improve powder fluidity or keep the shape after filling, so that the application range of the flux-cored wire is widened, and the flux-cored wire is suitable for industrial production. And the device is suitable for various working environments, and the production quality of the flux-cored wires is improved.

Description

Technical Field

[0001] This invention relates to the field of flux-cored welding wire technology, specifically to a self-shielded flux-cored welding wire and its production method. Background Technology

[0002] Welding wire is a metal wire used as filler metal or to conduct the electric arc during welding. After melting, it forms a weld to connect the workpiece. Flux-cored welding wire is a welding material with a flux-cored core material inside the tube. It protects the molten pool through a combination of gas and slag, and has the characteristics of stable arc, beautiful weld formation, and high deposition efficiency. The flux core provides arc stabilization and slag formation, forming a dual protective layer of gas and molten slag. Its tensile strength is superior to that of solid welding wire. Therefore, "the original poor filler effect and simple and quick manufacturing process of solid welding wire and flux-cored welding wire are no longer sufficient to achieve the high-quality and rapid manufacturing process of today," specifically in the following aspects: (1) When preparing flux-cored wire, due to the single material, it is not possible to make flux-cored wire with different properties for different working environments, which reduces the quality of flux-cored wire preparation; (2) When preparing flux-cored wire, the entire preparation process cannot be inspected, which reduces the environmental friendliness of the preparation process; (3) After the flux-cored wire is prepared, only a rough appearance inspection is performed, and the chemical composition, service life and weather resistance of the flux-cored wire cannot be fully inspected, which increases the defect rate of flux-cored wire. Summary of the Invention

[0003] The purpose of this invention is to provide a self-protected flux-cored wire and its production method to solve the problems mentioned in the background art regarding the current preparation of flux-cored wires: (1) When preparing flux-cored wires, due to the single material, it is not possible to make flux-cored wires with different properties for different working environments, which reduces the quality of flux-cored wire preparation; (2) When preparing flux-cored wires, the entire preparation process cannot be inspected, which reduces the environmental friendliness of the preparation process; (3) After the flux-cored wire is prepared, only a rough appearance inspection is performed, and the chemical composition, service life and weather resistance of the flux-cored wire cannot be fully inspected, which increases the defect rate of flux-cored wires.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for producing a self-shielded flux-cored welding wire, the preparation method comprising the following steps: S1, Material Handling S1.1 Steel strip preparation; ① Raw material selection; ② Uncoiling and cleaning; ③ Slitting; S1.2 Steel strip forming; The cleaned narrow steel strip is fed into the forming unit; S1.3 Powder preparation; ① Formula design, slag-forming agent, deoxidizer, gas-forming agent, alloying agent, arc stabilizer, binder; ② Powder processing; ③ Filling; S1.4 Closing and initial compaction; S2, Processing and Treatment S2.1 Drawing and reducing diameter, ① finish rolling, ② straightening, ③ surface treatment; S2.2 Finished product winding; S2.3 Sealed packaging; S3, Quality Inspection S3.1 Raw material inspection: composition, size, moisture, and cleanliness of steel strip and powder raw materials; S3.2 Process monitoring: forming size, filling rate, closing quality, drawing dimensional tolerance, surface quality, and winding quality; S3.3 Final product inspection: ① Visual inspection: diameter, ovality, and surface defects; ② Chemical composition analysis: cladding metal; ③ Welding process performance testing: arc stability and spatter size; ④ Mechanical property testing of cladding metal: tensile strength and yield strength; ⑤ Diffusible hydrogen content detection. S4. Packaging and Transportation S4.1 Packaging cleaning: ① Dust removal, ② Drying, ③ Sterilization; S4.2 Product transportation: Secure the product and store it in a dry place.

[0005] A self-shielded flux-cored welding wire, the flux formulation of which consists of 48% metal powder mixture, 42% slag-forming agent, 2% deoxidizer, 3% gas-generating agent, 1% alloying agent, 3% arc-stabilizing agent, and 1% binder.

[0006] Preferably, in step S1, the filling involves precisely metered dry powder being uniformly, continuously, and stably filled into the cavity of the shaped steel strip using a powder filling machine.

[0007] Preferably, the filling process in step S1 needs to be carried out in a dry, low-humidity environment.

[0008] Preferably, the formula for calculating the reduction in drawing area is RA = (A0 - A1) / A0 100%, in the calculation formula, A0 is the cross-sectional area of ​​the welding wire before drawing, in mm², and A1 is the cross-sectional area of ​​the welding wire after drawing, in mm².

[0009] Preferably, the formula for calculating the number of forming passes for the steel strip is n=k. (H0-Hf) / t, where n is the minimum number of forming passes, H0 is the initial width of the raw material strip in mm, Hf is the final unfolded width of the cross section in mm, t is the material thickness in mm, and k is the complexity coefficient.

[0010] Preferably, when k is taken as a coefficient, the simple cross section is 0.8~1.2 and the complex cross section is 1.5~2.5.

[0011] Preferably, the bending moment M in a single pass during the steel strip forming process is σy. b t² / 6 K.

[0012] Preferably, in the formula, σy is the yield strength of the material in MPa, b is the width of the bending zone in mm, t is the thickness of the material in mm, and K is a correction coefficient, which is taken as 1.2~1.5 to take into account the hardening effect.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, by carefully designing the flux powder formulation according to the target performance of the welding wire, typically includes: slag-forming agent: forming slag, protecting the molten pool, controlling the metallurgical reaction of the molten pool, and improving weld formation; deoxidizer: removing oxygen and nitrogen from the molten pool, preventing porosity and embrittlement; gas-generating agent: decomposing upon heating to produce protective gas, forming a gas shield at the end of the welding wire to isolate air; alloying agent: adding alloying elements to the deposited metal to achieve the required chemical composition and performance; arc stabilizer: improving arc stability; and binder: sometimes adding a small amount of binder to improve the fluidity of the flux powder or to maintain its shape after filling. This improves the applicability of flux-cored welding wire, making it suitable for various working environments and enhancing the production quality of flux-cored welding wire.

[0014] 2. This invention establishes strict quality control points at each key stage of production, monitoring the composition, size, moisture content, and cleanliness of raw materials such as steel strips and powders. It also remotely monitors forming dimensions, filling rate, closure quality, drawing tolerances, surface quality, and winding quality. Furthermore, it detects harmful substances in exhaust gases and air during production, thus monitoring the environmental impact of the production process and ensuring its environmental performance.

[0015] 3. This invention inspects the final product, detecting diameter, ovality, and surface defects. Then, it analyzes the chemical composition of the product using the deposited metal. Next, it tests the arc stability, spatter size, slag removal, and smoke using welding process performance testing. Finally, it tests the tensile strength, yield strength, elongation, and impact toughness of the product using the mechanical properties of the deposited metal. This comprehensive approach enables the inspection of the product and reduces the defect rate in production. Attached Figure Description

[0016] Figure 1 This is a flowchart of the production method of the high rust-resistant flux-cored welding wire of the present invention; Figure 2 This is a compositional diagram of the high rust-resistant flux-cored welding wire of the present invention; Figure 3 This is a partial logic code diagram of the forming unit in the production method of the high rust-resistant flux-cored welding wire of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: Please see Figures 1-3 A method for producing a self-shielded flux-cored welding wire, the preparation method comprising the following steps: S1, Material Handling S1.1 Steel strip preparation; ① Raw material selection; ② Uncoiling and cleaning; ③ Slitting; S1.2 Steel strip forming: Cleaned narrow steel strips are fed into the forming unit; S1.3 Powder preparation: ① Formula design, slag-forming agent, deoxidizer, gas-generating agent, alloying agent, arc-stabilizing agent, binder; ② Powder processing; ③ Filling; S1.4 Closing and initial compaction: Workers select cold-rolled steel strips of low-alloy steel with specific compositions. The width, thickness, and surface quality of the steel strip are crucial. The large coils of steel strip are uncoiled, and surface oil and rust are removed by a cleaning device to ensure subsequent processing. The reliable combination and purity of the flux are ensured. Then, according to the final welding wire diameter requirements, the wide steel strip is precisely cut longitudinally into narrow strips of the required width. The cleaned narrow steel strips are then fed into a forming unit. Passing through a series of precision rollers, the steel strips are gradually bent into a specific cross-sectional shape, forming an open tubular structure to hold the flux. The forming process requires extremely high precision control to ensure the stability of subsequent filling and closure. This is the core technology of self-shielded welding wire. Based on the target performance of the welding wire, the flux formulation is carefully designed. The formulation typically includes a slagging agent. Forming slag to protect the molten pool, controlling the metallurgical reaction in the molten pool, and improving weld formation; deoxidizer: removing oxygen and nitrogen from the molten pool to prevent porosity and embrittlement; gas-generating agent: decomposing upon heating to produce protective gas, forming a gas shield at the tip of the welding wire to isolate air; alloying agent: adding alloying elements to the deposited metal to achieve the required chemical composition and properties; arc stabilizer: improving arc stability; binder: sometimes adding a small amount of binder to improve the flowability of the flux powder or to maintain its shape after filling, thereby increasing the applicability of flux-cored welding wire, making it suitable for various working environments, and improving the production efficiency of flux-cored welding wire. To ensure product quality, various raw materials are weighed according to precise proportions, mixed evenly, and usually need to be crushed and ground to a specified particle size, and strictly dried to remove moisture. The precisely measured dry powder is evenly, continuously and stably filled into the cavity of the forming steel strip by a powder filling machine. The open steel strip filled with powder then enters the closing roller. The closing roller tightly rolls the edges of the open steel strip together, completely sealing the powder inside the cavity formed by the steel strip. At the same time, the closing process will initially compact the powder inside, reduce voids, and improve filling density and uniformity. S2, Processing and Treatment S2.1 Drawing and Reduction, ① Finishing Rolling, ② Straightening, ③ Surface Treatment, S2.2 Finished Product Winding, S2.3 Sealed Packaging: The closed welding wire blank enters the drawing unit. The welding wire blank passes through a series of gradually decreasing drawing dies. Under the action of strong drawing force and lubricant, the diameter of the welding wire is gradually drawn to close to the final target size. The drawing process causes the steel strip material to undergo plastic deformation and harden, while further compacting the internal flux powder. Some processes add a finishing rolling process after drawing to make the welding wire obtain a more accurate diameter tolerance, a more rounded cross-sectional shape and a smoother surface, eliminate the bending generated during drawing, and make the welding wire straight. Then, it is slightly polished or cleaned to remove the drawing lubricant and other contaminants remaining on the surface. Then, the continuously finished welding wire is wound on the welding wire reel according to the weight required by the customer. The winding must be neat, tight, without crossing, and without pressure damage to ensure smooth wire feeding during welding. S3, Quality Inspection S3.1 Raw material inspection: composition, size, moisture, and cleanliness of steel strip and powder raw materials. S3.2 Process monitoring: forming dimensions, filling rate, closure quality, drawing dimensional tolerances, surface quality, and winding quality. S3.3 Final product inspection: ① Visual inspection: diameter, ovality, surface defects; ② Chemical composition analysis: cladding metal; ③ Welding process performance testing: arc stability, spatter size; ④ Mechanical property testing of cladding metal: tensile strength, yield strength; ⑤ Diffusible hydrogen content detection. Strict quality control points are established at each key production process. The composition, size, moisture, and cleanliness of steel strip and powder raw materials are checked, and then the forming dimensions, filling rate, and closure quality are remotely monitored. The process involves testing for quantity, drawing dimensional tolerances, surface quality, and winding quality. During the manufacturing process, it also monitors the waste gas and harmful substances in the air to ensure environmental performance. The final product is then inspected, including diameter, ovality, and surface defects. Next, the chemical composition of the product is analyzed using the deposited metal. Then, the arc stability, spatter size, slag removal, and smoke emissions are tested using welding process performance testing. Finally, the tensile strength, yield strength, elongation, and impact toughness of the product are tested using the mechanical properties of the deposited metal. This comprehensive testing process reduces the product defect rate. S4. Packaging and Transportation S4.1 Packaging cleaning: ① Dust removal, ② Drying, ③ Sterilization. S4.2 Product transportation: Secure the product and store it in a dry place. Because the flux powder in self-shielded welding wire is highly susceptible to moisture absorption, moisture absorption can lead to serious porosity, increased spatter, and unstable arc during welding. The wound wire spool must be immediately placed in a sealed package containing a high-efficiency moisture-proof material, a built-in desiccant bag, and an aluminum foil moisture-proof film. This is usually a vacuum-sealed, inert gas-filled plastic bag to ensure the packaging remains sealed throughout transportation, storage, and until use.

[0019] A self-shielded flux-cored welding wire, the flux formulation of which consists of 48% metal powder mixture, 42% slag-forming agent, 2% deoxidizer, 3% gas-generating agent, 1% alloying agent, 3% arc-stabilizing agent, and 1% binder.

[0020] In this embodiment: in step S1, the filling involves precisely metered dry powder being uniformly, continuously, and stably filled into the cavity of the shaped steel strip using a powder filling machine.

[0021] In this embodiment: the filling process in step S1 needs to be carried out in a dry, low-humidity environment.

[0022] In this embodiment, the formula for calculating the drawing reduction ratio is RA = (A0 - A1) / A0 100%, in the calculation formula, A0 is the cross-sectional area of ​​the welding wire before drawing, in mm², and A1 is the cross-sectional area of ​​the welding wire after drawing, in mm².

[0023] In this embodiment: the formula for calculating the number of steel strip forming stages is n=k. (H0-Hf) / t, where n is the minimum number of forming passes, H0 is the initial width of the raw material strip in mm, Hf is the final unfolded width of the cross section in mm, t is the material thickness in mm, and k is the complexity coefficient.

[0024] In this embodiment: when k is taken as a coefficient, the simple cross section is 0.8~1.2, and the complex cross section is 1.5~2.5.

[0025] In this embodiment: the single-pass bending moment M=σy during steel strip forming b t² / 6 K.

[0026] In this embodiment: σy is the yield strength of the material in MPa, b is the width of the bending zone in mm, t is the thickness of the material in mm, and K is a correction factor, which is taken as 1.2~1.5 to take into account the hardening effect.

[0027] Example 2: As shown in the figure, unlike Embodiment 1, the self-shielded flux-cored welding wire and its production method in this embodiment include the following management steps: S1, Material Handling S1.1 Steel strip preparation; ① Raw material selection; ② Uncoiling and cleaning; ③ Slitting; S1.2 Steel strip forming; The cleaned narrow steel strip is fed into the forming unit; S1.3 Powder preparation; ② Powder processing; ③ Filling; S1.4 Closing and initial compaction.

[0028] S2, Processing and Treatment S2.1 Drawing and reducing diameter, ① precision rolling, ② straightening, ③ surface treatment, S2.2 Finished product winding, S2.3 Sealed packaging.

[0029] S3, Quality Inspection S3.1 Final product inspection: ① Visual inspection: diameter, ovality, surface defects; S3.2 Chemical composition analysis: cladding metal; S3.3 Welding process performance testing: arc stability, spatter size.

[0030] S4. Packaging and Transportation S4.1 Packaging cleaning: ① Dust removal, ② Drying, ③ Sterilization. S4.2 Product transportation: Secure the product and store it in a dry place. Because the flux powder of self-shielded welding wire is extremely prone to moisture absorption, moisture absorption will cause serious porosity, increased spatter, and unstable arc during welding. The wound wire spool must be immediately placed into a sealed package with a desiccant bag with high-efficiency moisture-proof material and an aluminum foil moisture-proof film.

[0031] In summary, compared to Example 2, Example 1 features a carefully designed flux powder formulation based on the target performance of the welding wire. This formulation typically includes: a slag-forming agent (to form slag, protect the molten pool, control the metallurgical reaction in the molten pool, and improve weld formation); a deoxidizer (to remove oxygen and nitrogen from the molten pool, preventing porosity and embrittlement); a gas-generating agent (to decompose upon heating to produce protective gas, forming a gas shield at the end of the welding wire to isolate air); an alloying agent (to add alloying elements to the deposited metal to achieve the required chemical composition and performance); an arc stabilizer (to improve arc stability); and a binder (sometimes a small amount of binder is added to improve the fluidity of the flux powder or to maintain its shape after filling). This enhances the applicability of the flux-cored welding wire, making it suitable for various working environments and improving the production quality of the flux-cored welding wire.

[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for producing a self-shielded flux-cored welding wire, characterized in that: Its preparation method includes the following steps: S1, Material Handling S1.1 Steel strip preparation; ① Raw material selection; ② Uncoiling and cleaning; ③ Slitting; S1.2 Steel strip forming; The cleaned narrow steel strip is fed into the forming unit; S1.3 Powder preparation; ① Formula design, slag-forming agent, deoxidizer, gas-forming agent, alloying agent, arc stabilizer, binder; ② Powder processing; ③ Filling; S1.4 Closing and initial compaction; S2, Processing and Treatment S2.1 Drawing and reducing diameter, ① finish rolling, ② straightening, ③ surface treatment; S2.2 Finished product winding; S2.3 Sealed packaging; S3, Quality Inspection S3.1 Raw material inspection: composition, size, moisture, and cleanliness of steel strip and powder raw materials; S3.2 Process monitoring: forming size, filling rate, closing quality, drawing dimensional tolerance, surface quality, and winding quality; S3.3 Final product inspection: ① Visual inspection: diameter, ovality, and surface defects; ② Chemical composition analysis: cladding metal; ③ Welding process performance testing: arc stability and spatter size; ④ Mechanical property testing of cladding metal: tensile strength and yield strength; ⑤ Diffusible hydrogen content detection. S4. Packaging and Transportation S4.1 Packaging cleaning: ① Dust removal, ② Drying, ③ Sterilization; S4.2 Product transportation: Secure the product and store it in a dry place.

2. A self-shielded flux-cored welding wire, based on the production method described in claim 1, characterized in that: The reagent formulation consists of 48% metal powder mixture, 42% slag-forming agent, 2% deoxidizer, 3% gas-generating agent, 1% alloying agent, 3% arc-stabilizing agent, and 1% binder.

3. The method for producing a self-shielded flux-cored welding wire according to claim 1, characterized in that: In step S1, the filling process involves precisely metered dry powder being uniformly, continuously, and stably filled into the cavity of the shaped steel strip using a powder filling machine.

4. The method for producing a self-shielded flux-cored welding wire according to claim 1, characterized in that: The filling process in step S1 must be carried out in a dry, low-humidity environment.

5. The method for producing a self-shielded flux-cored welding wire according to claim 1, characterized in that: The formula for calculating the reduction in drawing area is RA = (A0 - A1) / A0 100%, in the calculation formula, A0 is the cross-sectional area of ​​the welding wire before drawing, in mm², and A1 is the cross-sectional area of ​​the welding wire after drawing, in mm².

6. The method for producing a self-shielded flux-cored welding wire according to claim 1, characterized in that: The formula for calculating the number of steel strip forming passes is n=k. (H0-Hf) / t, where n is the minimum number of forming passes, H0 is the initial width of the raw material strip in mm, Hf is the final unfolded width of the cross section in mm, t is the material thickness in mm, and k is the complexity coefficient.

7. The method for producing a self-shielded flux-cored welding wire according to claim 6, characterized in that: When k is chosen as a coefficient, the simple cross section is 0.8~1.2, and the complex cross section is 1.5~2.

5.

8. The method for producing a self-shielded flux-cored welding wire according to claim 1, characterized in that: The single-pass bending moment M=σy in the steel strip forming process b t² / 6 K.

9. A method for producing a self-shielded flux-cored welding wire according to claim 8, characterized in that: In the formula, σy is the yield strength of the material in MPa, b is the width of the bending zone in mm, t is the thickness of the material in mm, and K is a correction factor, which is taken as 1.2~1.5 to take into account the hardening effect.

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