Mixed gas shielded solid welding wire with tensile strength larger than or equal to 1150Mpa and preparation method and application of mixed gas shielded solid welding wire

Abstract

The invention relates to the technical field of welding materials, in particular to a mixed gas shielded solid welding wire with the tensile strength larger than or equal to 1150Mpa and a preparation method and application of the mixed gas shielded solid welding wire. The preparation method comprises the steps that S1, surface pretreatment, drawing treatment and annealing treatment are conducted on wire rod steel, and an intermediate wire is obtained; s2, carrying out surface treatment on the intermediate wire, and then carrying out drawing treatment; s3, the drawn intermediate wire is subjected to annealing treatment, and then the operation in the step S2 is repeated to obtain a semi-finished product; and S4, copper plating treatment, sizing and polishing treatment are conducted on the semi-finished product, and a welding wire finished product is obtained after wire winding. By means of the preparation method and adjustment of the adding proportion of all the components in a welding material alloy system, the welding wire finished product with excellent wire feeding stability is prepared and can fully meet the requirement of continuous welding operation of a robot for wire feeding stability, the splashing phenomenon in the welding process is effectively reduced, and the welding quality is improved. The welding quality and the welding efficiency are improved; and meanwhile, the welding wire can have excellent equal-strength matching performance.

Description

Technical Field

[0001] The present invention relates to the technical field of welding materials, and in particular to a mixed gas solid welding wire with a tensile strength of ≥1150 MPa, and a preparation method and application thereof. Background Art

[0002] Ultra-high-strength steel with a yield strength of 960 MPa and above is increasingly being used in a wide range of fields, including construction machinery, coal mining machinery, and port machinery, thanks to its superior performance, driven by a comprehensive approach encompassing optimized structural design, reduced equipment weight, increased load-bearing capacity, simplified transportation and installation, and cost control. However, the widespread application of ultra-high-strength steel requires the support of compatible welding consumables. The use of ultra-high-strength steel plates with a yield strength of 960 MPa and above requires welding consumables of comparable strength. Currently, the maximum yield strength of gas-shielded solid welding wire on the market is insufficient to match that of ultra-high-strength steel plates. Under the current design model, which relies on wire strength for stress calculations, ultra-high-strength steel plates such as Q1030 and Q1100 can only be used in low-stress or compressive stress zones, limiting their application and preventing them from fully realizing their performance advantages. Furthermore, the industry is placing higher demands not only on the mechanical properties of welding consumables but also on the process performance of welding wires, aiming to achieve both improved production efficiency and product quality.

[0003] Patent publication number CN103331529A discloses a mixed gas shielded welding wire with a tensile strength ≥1100MPa. Although the welding wire is micro-alloyed with Ti+V+B, which can make the weld metal obtain uniform and fine acicular ferrite, thereby strengthening the weld metal; however, Ti+V+B micro-alloy strengthening will lead to a large amount of oxides on the weld surface, which is prone to produce a large amount of surface oxides during multi-layer and multi-pass welding, making arc starting difficult, increasing the weld defect rate, and low operability, making it unsuitable for use in robot automatic welding.

[0004] Patent publication number CN118951483A discloses an 1100MPa-grade solid gas shielded welding wire. Among the components of this welding wire, V is a strong carbide-forming element. The carbides formed are stable below 650°C and have a certain age-hardening effect. However, V easily forms refractory oxides, which are prone to defects during gas shielded welding. In addition, the impact energy of the weld of this welding wire at -40°C is low, at 28-55J, which means that in low-temperature environments, the impact resistance of the weld is poor and brittle fracture is prone to occur. The process window of this welding wire is also narrow, the control requirements for welding parameters are extremely strict, and the on-site operability is low, which to a certain extent limits its large-scale promotion and application.

[0005] The present invention provides a mixed gas solid welding wire with a tensile strength of ≥1150Mpa and a preparation method and application thereof, so as to solve the problems of poor equal strength matching and unstable process performance of existing welding wires in the prior art. Summary of the Invention

[0006] The purpose of the present invention is to provide a mixed gas solid welding wire with a tensile strength of ≥1150Mpa and its preparation method and application, so as to solve the problems of poor equal strength matching and unstable process performance of existing welding wires in the prior art.

[0007] The technical solution of the present invention is: a method for preparing a mixed gas solid welding wire with a tensile strength of ≥1150 MPa, comprising the following steps: S1. Surface pretreatment of the wire rod steel is performed, followed by drawing and annealing to obtain an intermediate wire; S2, performing surface treatment on the intermediate filament, and then performing re-drawing treatment; S3, annealing the drawn intermediate wire, and then repeating the operation of step S2 to obtain a semi-finished product; S4, copper plating the semi-finished product, then sizing and polishing it, and then winding it to obtain the finished welding wire; Measured by weight percentage, the chemical composition of the wire rod steel is: C: 0.06%-0.10%, Si: 0.70%-0.80%, Mn: 1.70%-1.90%, Cr: 0.40%-0.60%, Ni: 3.00%-3.50%, Mo: 0.50%-0.70%, Ti: 0.05%-0.15%, B: 0.0008%-0.002%, Zr: 0.005%-0.010%, Nb: 0.03%-0.07%, P, S≤0.015%, O, N≤50ppm, and the balance is Fe.

[0008] Preferably, in step S1, the surface pretreatment includes peeling treatment, grinding treatment, cleaning treatment, boron coating treatment, and drying treatment in sequence; In step S2, the surface treatment includes fine grinding, cleaning, boron coating, and drying in sequence.

[0009] Preferably, the grinding process is performed using a 60-140 mesh sand belt; the fine grinding process is performed using a 120-180 mesh sand belt; the cleaning process includes a pickling process and a water washing process; The treatment temperature of the boron coating treatment is 85-95°C.

[0010] Preferably, in step S1 and step S3, the annealing temperature of the annealing treatment is 600-720° C., the protective atmosphere is nitrogen, and the holding time is 8-12 hours; during the re-drawing process, the drawing die entrance angle is 10-12°.

[0011] Preferably, in step S4, the copper plating treatment is to treat the semi-finished product with a copper plating bath; in the copper plating bath, the concentration of H2SO4 is 70-80g / L, and the concentration of Fe 2＋ The concentration of Cu does not exceed 60g / L, 2＋ The concentration is 30-40g / L; The semi-finished product needs to be rinsed with high-pressure hot water before and after the copper plating treatment.

[0012] Preferably, the relaxed diameter of the finished welding wire is not less than 800 mm, and the warp distance is not more than 5 mm.

[0013] The present application also provides a mixed gas solid welding wire with a tensile strength ≥1150 MPa, which is prepared using the above-mentioned preparation method.

[0014] The present application also provides an application of the above-mentioned welding wire, including: under the protection of a mixed atmosphere, using the welding wire and a flux matching the welding wire to perform welding processing on a test plate.

[0015] Preferably, the mixed atmosphere comprises 80% argon + 20% carbon dioxide; The groove of the test plate uses a double V groove; the test plate includes a Q1030 steel plate.

[0016] Preferably, during the welding process, the preheating temperature is 80-120°C, the welding heat input is ≤10KJ / cm, and the processing temperature of the post-heat treatment is 250°C.

[0017] Compared with the prior art, the advantages of the present invention are: (1) The present invention provides a mixed gas solid welding wire with a tensile strength of ≥1150Mpa and its preparation method and application. Through the preparation method and combined with the adjustment of the addition ratio of each component in the alloy system of Mn, Cr, Ni, Mo, Ti, Nb, Zr, etc., a welding wire product with excellent wire feeding stability can be prepared, so that the welding wire product can fully meet the requirements of robot continuous welding operation for wire feeding stability, effectively reduce the spattering phenomenon during welding, and improve welding quality and welding efficiency; at the same time, it can also make the welding wire have excellent equal strength matching, so that the welding joint formed by the welding wire product after welding has excellent mechanical properties; the tensile strength of the welding joint is significantly improved, and it can withstand high-intensity tensile loads without being damaged, ensuring the reliability of the welding structure; and the welding joint has excellent toughness at -40℃, effectively avoiding the risk of low-temperature brittle fracture; solving the problems of poor equal strength matching and unstable process performance of existing welding wires in the prior art.

[0018] (2) The present invention provides a mixed gas solid welding wire with a tensile strength ≥1150Mpa, and its preparation method and application. The finished welding wire prepared by the preparation method has excellent equal strength matching performance and can be equal strength matched with Q1030 steel plates; and when the finished welding wire is used to weld Q1030 steel plates under the welding process parameters provided in the present application, the mechanical properties of the deposited metal can meet Rp0.2≥1150Mpa, Rm≥1030Mpa, elongation ≥14%, KV2≥47J at -40℃; the performance of the weld is excellent, which can effectively solve the problem of high crack sensitivity of high-strength welds and improve the weld qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic structural diagram of the upper bevel of the test plate according to the present invention; Figure 2 This is a waveform diagram corresponding to the welding wire product obtained in Example 1 of the present invention during continuous welding; Figure 3 This is a waveform diagram corresponding to the continuous welding of the finished welding wire obtained in Example 2 of the present invention; Figure 4 This is the waveform diagram corresponding to the continuous welding of the finished welding wire obtained in Example 3 of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be described in further detail below with reference to specific embodiments: A method for preparing a mixed gas solid welding wire with a tensile strength of ≥1150 MPa, comprising the following steps: S1. Select wire rod steel with specific components and perform surface pretreatment on the wire rod steel, that is, first perform shelling treatment on the wire rod steel to remove the rust layer on the surface of the wire rod steel; then use a 60-140 mesh sand belt to grind the wire rod steel to effectively remove the iron oxide scale on the surface of the wire rod steel and ensure the smoothness of the surface of the wire rod steel; then, perform pickling treatment, water washing treatment and other cleaning treatments on the wire rod steel in sequence to thoroughly remove the dirt and impurities remaining on the surface of the wire rod steel; then, perform boron coating treatment on the wire rod steel at a temperature of 85-95℃ to improve the surface lubricity of the welding wire, which is more conducive to the subsequent drawing process; and after the boron coating treatment is completed, it is dried to provide good conditions for subsequent processing. After surface pretreatment, the wire rod is then transferred to a drawing die for drawing to produce a smaller diameter wire. Finally, the drawn wire rod is annealed in an inert atmosphere at 600-720°C for 8-12 hours to eliminate internal stress and improve the microstructure. This annealing treatment results in an intermediate wire with stable performance. Annealing in a nitrogen atmosphere effectively reduces oxide deposition on the intermediate wire surface, improving the welding performance of the resulting finished wire.

[0021] In this application, the welding material alloy system is designed to be a Mn-Cr-Ni-Mo-Ti alloy system, that is, the chemical composition of the wire rod steel is, by weight percentage: C: 0.06%-0.10%, Si: 0.70%-0.80%, Mn: 1.70%-1.90%, Cr: 0.40%-0.60%, Ni: 3.00%-3.50%, Mo: 0.50%-0.70%, Ti: 0.05%-0.15%, B: 0.0008%-0.002%, Zr: 0.005%-0.010%, Nb: 0.03%-0.07%, P, S≤0.015%, O, N≤50ppm, and the balance is Fe. By designing the welding material alloy system as a Mn-Cr-Ni-Mo-Ti alloy system, the synergistic strengthening effects of alloy solid solution strengthening, fine grain strengthening mechanisms, and the precipitation phases of microalloying elements and dislocation substructures can be comprehensively utilized to ensure the high strength characteristics of the deposited metal. At the same time, the formation of hardened microstructures is effectively prevented, significantly improving the crack resistance of the weld. By rationally adjusting the ratios of the main alloys such as Mn, Ni, Mo, and Cr, the plasticity and toughness of the weld can be optimized. The addition of trace elements such as B, Nb, and Zr in appropriate amounts, and strict control of the contents of elements such as S, P, O, and N, can further improve the material properties. Based on the research on the metallurgical behavior of each alloying element and their interaction, this system ensures that the ideal microstructure composed mainly of low-carbon tempered martensite and low-carbon tempered bainite is obtained after welding.

[0022] The microalloying elements Ti, Zr, and Nb in this alloy system play a vital role, specifically as follows: The addition of appropriate amounts of Ti and Zr microalloying elements to the weld metal of MAG welds of low-alloy high-strength steels can significantly optimize welding process performance. On the one hand, these elements effectively improve the transition morphology of the weld droplet, reduce the weld spatter rate, and enhance wire feedability and arc stability. Furthermore, due to the strong affinity between Ti and O and N, and between Zr and O and C, Ti and Zr microalloying elements can achieve dual purification effects during welding by forming stable oxides / nitrides, assisting in deoxidation and nitrogen fixation. Furthermore, TiO, TiN, ZrO, and ZrC, generated during the high-temperature welding process, can serve as heterogeneous nucleation nuclei for the α-phase and preferentially precipitate within the primary austenite grains. By refining the grain size and optimizing the microstructure, they achieve a synergistic strengthening effect, enhancing weld metal strength and improving low-temperature impact toughness. The optimal Ti addition level in the weld metal requires dynamic adjustment, taking into account the synergistic effects of coexisting alloying elements and the actual oxygen content.

[0023] In weld metal, Nb exists primarily in two forms: First, some Nb atoms are distributed in solid solution within the ferrite matrix. Due to their significant differences in atomic radius and electronegativity from Fe, they cause lattice distortion and increase crystallization resistance, thereby inhibiting grain coarsening. Second, Nb combines with carbon and nitrogen to form nanoscale second-phase Nb(C,N) particles. Some Nb(C,N) particles are uniformly dispersed within the austenite grains, acting as heterogeneous nucleation sites that promote grain refinement and produce dispersion strengthening. Other Nb(C,N) particles are concentrated at austenite grain boundaries, strengthening the austenite by pinning dislocations. However, excessive precipitation can lead to grain boundary embrittlement and a loss of ductility and toughness. Based on these mechanisms, to achieve a balanced balance between strength and toughness, the Nb content must be strictly controlled below 0.07% to avoid degradation of microstructure and properties caused by excessive precipitation of the second phase.

[0024] S2. Surface treatment is performed on the intermediate wire obtained, i.e., fine grinding is first performed on the intermediate wire using a 120-180 mesh abrasive belt. The fine mesh abrasive belt can effectively remove the surface iron oxide and reduce the scratches on the surface of the welding wire, which is beneficial to the subsequent drawing; followed by pickling, water washing and other cleaning treatments; then, the wire rod is subjected to boron coating at a temperature of 85-95°C; and after the boron coating is completed, it is dried. After that, the surface-treated intermediate wire is conveyed to a drawing die for re-drawing, wherein the inlet angle of the drawing die is preferably 10-12°, which helps to make the internal and external deformation of the welding wire more uniform and reduce wire breakage.

[0025] S3. Annealing the drawn intermediate filament in an inert atmosphere at 600-720° C. for several hours, and then repeating step S2 to obtain a semi-finished product.

[0026] S4. First, the semi-finished product is rinsed with high-pressure hot water to remove impurities on the surface of the semi-finished wire; then, the semi-finished wire is transported to the copper plating tank and copper-plated under the action of the copper plating tank liquid; then, the semi-finished wire after the copper plating is washed with water to remove the copper plating tank liquid remaining on the surface of the semi-finished wire; wherein, the quality of copper plating not only affects the surface quality of the welding wire, but also directly affects the customer's use process, and further affects the welding quality of the customer's product; and the copper plating quality depends on the copper plating tank liquid; therefore, it is necessary to strictly control the content of each component in the copper plating tank liquid; preferably, in the copper plating tank liquid, the concentration of H2SO4 is 70-80g / L, Fe 2＋ The concentration of Cu does not exceed 60g / L, 2＋ The concentration is 30-40g / L. The washed semi-finished wire is then sized and polished, and finally wound to produce the finished welding wire. This preparation method requires only two annealing steps, significantly improving production efficiency while ensuring product quality and performance, while effectively reducing material waste and achieving high process economics.

[0027] The present application also provides a mixed gas solid welding wire with a tensile strength of ≥1150Mpa, which is prepared using the above-mentioned preparation method; the relaxed diameter of the welding wire is controlled to be ≥800mm, and the warp distance is controlled to be ≤5mm, which helps to ensure the stability of wire feeding.

[0028] This application also provides the use of the aforementioned mixed gas solid welding wire with a tensile strength of ≥1150 MPa, comprising: welding a test plate using the wire and a matching flux under the protection of a mixed atmosphere, in accordance with the requirements of GB / T 39281-2020. The deposited metal mechanical properties must meet the following requirements: Rp0.2 ≥1150 MPa, Rm ≥1030 MPa, elongation ≥14%, and KV2 ≥47 J at -40°C. The test plate is a Q1030 steel plate, a Q1100 steel plate, or the like; the thickness of the test plate is preferably no more than 10 mm; the mixed atmosphere is preferably a protective atmosphere formed by a combination of 80% Ar and 20% CO2; during the welding process, the welding heat input is ≤10 kJ / cm, and the calculation formula for the welding heat input is: E=IUη / v, wherein I is the welding current in amperes; U is the arc voltage in volts; η is the welding thermal efficiency (dimensionless, usually between 0.6-0.9), and in the application, η=0.8; v is the welding speed in mm / s.

[0029] Furthermore, during the welding process, Figure 1As shown in the figure, the test plate groove uses a double V groove, and the preferred single-side angle is 30°; the preheating temperature of the butt-jointed test plate is 80℃-120℃, and the interlayer temperature of the butt-jointed test plate is not lower than the preheating temperature and not higher than 180℃; after welding is completed, the butt-jointed test plate is flame-heated to 250℃, and then slowly cooled with insulation cotton to effectively reduce the occurrence of hydrogen-induced cracking.

[0030] Example 1

[0031] The chemical composition of wire rod steel, by weight percentage, is: C: 0.09%, Si: 0.7%, Mn: 1.75%, Cr: 0.45%, Ni: 3.2%, Mo: 0.5%, Ti: 0.07%, B: 0.0012%, Zr: 0.008%, Nb: 0.05%, P: 0.008%, S: 0.007%, and the balance is Fe and unavoidable impurities.

[0032] S1. A wire rod steel having a diameter of 5.5 mm is sequentially subjected to a shelling treatment, a grinding treatment using a 60-mesh abrasive belt, an electrolytic pickling treatment using sulfuric acid, a cleaning treatment using pure water, a boron coating treatment at a temperature of 85° C., and a subsequent drying treatment. Thereafter, the surface pretreated wire rod steel is drawn to a diameter of 3.95 mm. Subsequently, the wire rod steel having a diameter of 3.95 mm is annealed under nitrogen protection at 600° C. and kept warm for 12 hours to obtain an intermediate wire. S2. Finely polish the intermediate wire using a 120-grit abrasive belt, then electrolytically pickle it with sulfuric acid and clean it with pure water. Boron-coated it at 85°C and then dried. The surface-treated intermediate wire is then conveyed to a drawing die at an entrance angle of 12° for redrawing, and the diameter of the intermediate wire is drawn to 3.15 mm. S3. Annealing the intermediate filament with a diameter of 3.15 mm at 650° C. under nitrogen protection for 8 h, and then repeating step S2 once to obtain a semi-finished product. S4, firstly wash the semi-finished product with high pressure water, then use H2SO4 with a concentration of 72g / L, Fe 2＋ The concentration is 32g / L and Cu 2＋ The semi-finished wire material after water washing is copper-plated with a copper plating bath solution with a concentration of 31g / L, and then it is washed with water to remove the residual copper plating bath solution on the surface. After that, it is sizing and polishing, and the finished welding wire with a diameter of φ1.2mm is obtained after winding. The relaxed diameter of the finished welding wire is 1000mm and the warp distance is 2mm.

[0033] An automatic welding robot was used to test the wire feeding stability of the finished wire during long-term welding, and continuous welding was performed for 5 minutes at 260A and 25V.

[0034] A Q1030 steel plate with a thickness of 10 mm was used; the groove adopted a double V-groove with a V-groove angle of 60° and a groove assembly gap of 1-2 mm; the protective atmosphere was a combination of 80% Ar and 20% CO2; the preheating temperature was 100°C; the welding heat input was 5.2 kJ / cm2; multi-layer and multi-pass submerged arc welding was used for welding, with the interpass temperature controlled at 100-180°C; after welding, the flame was heated to 250°C and thermal insulation cotton was used for slow cooling; finally, the welded product was obtained.

[0035] Example 2

[0036] The difference between this embodiment and Example 1 is that, in terms of weight percentage, the chemical composition of the wire rod steel is: C: 0.08%, Si: 0.8%, Mn: 1.80%, Cr: 0.40%, Ni: 3.0%, Mo: 0.5%, Ti: 0.09%, B: 0.0015%, Zr: 0.005%, Nb: 0.04%, P: 0.010%, S: 0.008%, and the balance is Fe and unavoidable impurities.

[0037] The difference between this embodiment and embodiment 1 is that: an 80-mesh sand belt is used for grinding, and a 140-mesh sand belt is used for fine grinding; in step S1, the annealing temperature is 620°C and the holding time is 10 hours; in step S3, the annealing temperature is 680°C and the holding time is 8 hours; the treatment temperature of the boron coating treatment is 90°C; in step S2, during the re-drawing process, the inlet angle of the drawing die is 11°; in the copper plating process, the concentration of H2SO4 in the copper plating bath is 75g / L, and the concentration of Fe 2＋ The concentration is 34g / L and Cu 2＋ The concentration of 34g / L was obtained. Finally, the finished welding wire had a relaxed diameter of 1200mm, a warp distance of 1mm, and a diameter of 1.2mm.

[0038] An automatic welding robot was used to test the wire feeding stability of the finished wire during long-term welding, and continuous welding was performed for 5 minutes at 260A and 25V.

[0039] A Q1030 steel plate with a thickness of 10 mm was used. The gas shielded welding groove adopted a double V-shaped groove with a V-shaped groove angle of 60° and a groove assembly gap of 1-2 mm. The protective atmosphere was a combination of 80% Ar and 20% CO2. The preheating temperature was 90°C. The welding heat input was 7.68 kJ / cm2. Multi-layer and multi-pass submerged arc welding was used for welding, with the interpass temperature controlled at 90-180°C. After welding, the flame was heated to 250°C and thermal insulation cotton was used for slow cooling. Finally, the welded product was obtained.

[0040] Example 3

[0041] The difference between this embodiment and Example 1 is that, in terms of weight percentage, the chemical composition of the wire rod steel is: C: 0.10%, Si: 0.7%, Mn: 1.70%, Cr: 0.55%, Ni: 3.4%, Mo: 0.6%, Ti: 0.10%, B: 0.0009%, Zr: 0.005%, Nb: 0.03%, P: 0.011%, S: 0.005%, and the balance is Fe and unavoidable impurities.

[0042] The difference between this embodiment and embodiment 1 is that: a 60-mesh sand belt is used for grinding, and a 180-mesh sand belt is used for fine grinding; in step S1, the annealing temperature is 650°C and the holding time is 12 hours; in step S3, the annealing temperature is 700°C and the holding time is 8 hours; the treatment temperature of the boron coating treatment is 85°C; in step S2, during the re-drawing process, the inlet angle of the drawing die is 10°; in the copper plating process, the concentration of H2SO4 in the copper plating bath is 76g / L, and the concentration of Fe 2＋ The concentration is 41g / L and Cu 2＋ The concentration of 35g / L was finally obtained, and the finished welding wire had a relaxed diameter of 1250mm, a warp distance of 1.5mm, and a diameter of 1.2mm.

[0043] An automatic welding robot was used to test the wire feeding stability of the finished wire during long-term welding, and continuous welding was performed for 5 minutes at 260A and 25V. A Q1030 steel plate with a thickness of 10 mm was used; the gas shielded welding groove adopted a double V-shaped groove with a V-shaped groove angle of 60° and a groove assembly gap of 1-2 mm; the protective atmosphere was a combination of 80% Ar and 20% CO2; the preheating temperature was 110°C; the welding heat input was 9.54 kJ / cm2; multi-layer and multi-pass submerged arc welding was used for welding, and the interpass temperature was controlled at 90-180°C; after welding, the flame was heated to 250°C and thermal insulation cotton was used for slow cooling; finally, the welded product was obtained.

[0044] In order to comprehensively evaluate the performance of the finished welding wires prepared in Examples 1-3, various performances were tested during and after continuous welding. The wire loosening resistance and wire feeding speed discrete deviation of the finished welding wires prepared in Examples 1-3 after 5 minutes of continuous welding are shown in Table 1, and the corresponding waveforms are shown in Table 1. Figure 2 、 Figure 3 、 Figure 4 As shown in the figure. The data dispersion standard deviation is an important indicator used to measure the degree of data dispersion in a data set. It reflects the average deviation of data points from the mean. When the standard deviation is larger, it means that the deviation of data points from the mean is greater, and the overall dispersion of the data is also higher.

[0045] Table 1. Numerical table of the finished welding wires prepared in Examples 1-3 after continuous welding for 5 minutes

[0046] From Table 1 and Figure 2 、 Figure 3 、 Figure 4 It can be seen that the discrete degrees of the key parameters of the finished welding wires prepared in Examples 1-3 during the automatic welding wire feeding process are all within a relatively reasonable range, the wire feeding is smooth, the wire feeding stability is good, and the requirements of long-term welding of the automatic welding robot are fully met; furthermore, the preparation method of the welding wire provided in this application is explained. By adjusting the addition ratio of components such as Mn, Cr, Ni, Mo, Ti, Nb, and Zr and combining it with the preparation method provided in this application, a finished welding wire with excellent wire feeding stability can be prepared. Specifically, in terms of the wire feeding resistance F, the data discrete standard deviation of the finished welding wire prepared in Example 2 is significantly smaller than the data discrete standard deviation of the finished welding wires prepared in Examples 1 and 2; the smaller the value, the more concentrated the data and the higher the stability; thus, it can be seen that the wire feeding resistance data discrete degree of the finished welding wire prepared in Example 2 is the smallest, and the wire feeding resistance performance is relatively more stable. Similarly, in terms of the wire feed port speed S1, the finished welding wire prepared in Example 2 has the smallest standard deviation, indicating that its data fluctuation in wire feed port speed is the smallest and the wire feed port speed stability is the best. In terms of the wire outlet speed S2, the finished welding wire prepared in Example 1 has a relatively small data discrete standard deviation, a more concentrated data distribution of the wire outlet speed, and a slightly better stability than the finished welding wires prepared in Examples 2 and 3; however, the finished welding wire prepared in Example 2 also has good stability of the wire outlet speed, which can meet the requirements of long-term welding by the automatic welding robot.

[0047] In order to evaluate the various post-weld properties of the finished welding wires prepared in Examples 1-3 above, the finished welded wires obtained in Examples 1-3 above were respectively subjected to tensile tests according to GB / T 228.1 and impact tests according to GB / T 229; and the mechanical properties of the welded joints were tested. The test results are shown in Table 2.

[0048] Table 2. Welding joint performance test results of the finished welding wires prepared in Examples 1-3.

[0049]

[0050] As can be seen from Table 2, after the finished welding wires prepared in Examples 1-3 were welded to the test plates using the above-mentioned welding parameters, the tensile strength of the welded joints was significantly higher than the index requirement of 1150 MPa, and the fracture locations all occurred on the base material, that is, on the test plates; in particular, the finished welding wire prepared in Example 2 had a tensile strength of more than 1300 MPa; this fully demonstrates that the welding wire prepared by the method provided in this application has an excellent tensile strength in its welded joint and can effectively withstand large tensile loads without breaking.

[0051] The welds of the finished welded products obtained in Examples 1-3 all have certain fluctuations in impact energy at -40°C; however, the welds of the finished welded products obtained in Examples 1-3 all have impact energy at -40°C significantly higher than the 47J requirement, especially the welds of the finished welded products obtained in Examples 1 and 2 all have impact energy of more than 60J at -40°C; this indicates that the welds on the finished welded products obtained in Examples 1-3 have better toughness at low temperatures. Similarly, the welds of the finished welded products obtained in Examples 1-3 all have impact energy at -40°C higher than the 47J requirement; this indicates that the welds on the finished welded products obtained in Examples 1-3 all have excellent toughness at low temperatures, that is, the toughness at the junction of the weld and the base material is higher; welding under the welding wire products and welding process parameters provided in Examples 1-3 can obtain welded products with better comprehensive mechanical properties.

[0052] In summary, when welding is performed according to the welding process provided by the present invention, the welding joint of the finished welding wire prepared by the preparation method provided by the present invention can fully meet the requirements of tensile strength ≥1150Mpa and -40℃ impact energy ≥47J, has reliable performance, and can function stably in complex working environments.

[0053] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and they are not intended to limit the scope of protection of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. A method for preparing a mixed gas solid welding wire with a tensile strength of ≥1150 MPa, characterized in that: The following steps are involved: S1. Surface pretreatment of the wire rod steel is performed, followed by drawing and annealing to obtain an intermediate wire; S2, performing surface treatment on the intermediate filament, and then performing re-drawing treatment; S3, annealing the drawn intermediate wire, and then repeating the operation of step S2 to obtain a semi-finished product; S4, copper plating the semi-finished product, then sizing and polishing it, and then winding it to obtain the finished welding wire; Measured by weight percentage, the chemical composition of the wire rod steel is: C: 0.06%-0.10%, Si: 0.70%-0.80%, Mn: 1.70%-1.90%, Cr: 0.40%-0.60%, Ni: 3.00%-3.50%, Mo: 0.50%-0.70%, Ti: 0.05%-0.15%, B: 0.0008%-0.002%, Zr: 0.005%-0.010%, Nb: 0.03%-0.07%, P, S≤0.015%, O, N≤50ppm, and the balance is Fe.

2. The method for preparing a mixed gas solid welding wire with a tensile strength of ≥1150 MPa according to claim 1, characterized in that: In step S1, the surface pretreatment includes peeling, grinding, cleaning, boron coating, and drying in sequence; In step S2, the surface treatment includes fine grinding, cleaning, boron coating, and drying in sequence.

3. The method for preparing a mixed gas solid welding wire with a tensile strength of ≥1150 MPa according to claim 2, characterized in that: The grinding process is performed using a 60-140 mesh sand belt; the fine grinding process is performed using a 120-180 mesh sand belt; the cleaning process includes a pickling process and a water washing process; The treatment temperature of the boron coating treatment is 85-95°C.

4. The method for preparing a mixed gas solid welding wire with a tensile strength of ≥1150 MPa according to claim 1, characterized in that: In step S1 and step S3, the annealing temperature of the annealing treatment is 600-720° C., the protective atmosphere is nitrogen, and the holding time is 8-12 hours; during the re-drawing process, the drawing die entrance angle is 10-12°.

5. The method for preparing a mixed gas solid welding wire with a tensile strength of ≥1150 MPa according to claim 1, characterized in that: In step S4, the copper plating treatment is to treat the semi-finished product with a copper plating bath; in the copper plating bath, the concentration of H2SO4 is 70-80g / L, Fe 2＋ The concentration of Cu does not exceed 60g / L, 2＋ The concentration is 30-40g / L; The semi-finished product needs to be rinsed with high-pressure hot water before and after the copper plating treatment.

6. The method for preparing a mixed gas solid welding wire with a tensile strength of ≥1150 MPa according to claim 1, characterized in that: The relaxed diameter of the finished welding wire is not less than 800 mm and the warp distance is not more than 5 mm.

7. A mixed gas solid welding wire with a tensile strength of ≥1150 MPa, characterized in that: The welding wire is prepared by the preparation method according to any one of claims 1 to 6.

8. The use of the mixed gas solid welding wire with a tensile strength of ≥1150 MPa as claimed in claim 7, characterized in that: include: Under the protection of the mixed atmosphere, the test plate is welded using the welding wire.

9. The use of the mixed gas solid welding wire with a tensile strength of ≥1150 MPa according to claim 8, characterized in that: The mixed atmosphere includes 80% argon + 20% carbon dioxide; The groove of the test plate uses a double V groove; the test plate includes a Q1030 steel plate.

10. The use of the mixed gas solid welding wire with a tensile strength of ≥1150 MPa according to claim 8, characterized in that: During the welding process, the preheating temperature is 80-120°C, the welding heat input is ≤10KJ / cm, and the processing temperature of the post-heat treatment is 250°C.

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