Welding wire for laser welding of aluminum-silicon coated plates, preparation method and application thereof

Abstract

The present invention relates to the technical field of aluminum-silicon coated plate welding, specifically a welding wire for aluminum-silicon coated plate laser welding, a preparation method and its application. The prepared welding wire includes a flux and a welding skin; the filling rate of the flux in the welding skin is 20-35%; the flux includes the following components by mass: 30-40 parts of iron powder, 3-11 parts of manganese powder, 5-9 parts of chromium powder, 4-6 parts of nickel powder, 6-12 parts of modified hexagonal boron nitride, 3-5 parts of titanium powder, 4-10 parts of copper powder, and 1-5 parts of rhenium oxide powder. The welding wire prepared by the present invention effectively improves the weld strength through the characteristics of hexagonal boron nitride itself, and at the same time, by storing carbon dioxide in hexagonal boron nitride and coating it, it plays a good protective role in the welding process.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum-silicon coated plate welding, and in particular to a welding wire for laser welding of aluminum-silicon coated plates, a preparation method and application thereof. Background Art

[0002] In recent years, with the continuous development of the automobile manufacturing industry, more and more new technologies have been applied in automobile welding. Laser welding is a new welding process in automobile manufacturing. Laser welding can automatically join and weld several steels, stainless steels, aluminum alloys, etc. of different materials, thicknesses, and coatings to form an integral plate, profile, sandwich panel, etc., to meet the different requirements of parts for material properties, and achieve lightweight equipment with the lightest weight, optimal structure, and best performance.

[0003] Aluminum-silicon coated plate is a commonly used material in the field of automobile manufacturing. As a high-strength material, it is often used in automobile anti-collision beams, B-pillars and other safety parts. The aluminum-silicon coated plate is composed of a substrate (hot-formed steel) and a coating. In order to prevent the surface of the substrate from being oxidized, a layer of aluminum-silicon coating is applied on the surface of the substrate. During the welding process, a protective gas needs to be blown in from the outside to protect the molten pool. It is greatly affected by the outside world, the operation is relatively cumbersome, and the cost is high. In addition, the chlorine element in the aluminum-silicon coated plate combines with the iron element to form an aluminum-iron intermetallic compound, which has a greater impact on the strength of the weld.

[0004] To this end, in response to the problems raised in the above background technology, technical personnel in this field have proposed a welding wire for laser welding of aluminum-silicon coated plates, a preparation method and an application thereof. Summary of the invention

[0005] The object of the present invention is to provide a welding wire for laser welding of aluminum-silicon coated plates, a preparation method and application thereof, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A welding wire for laser welding of aluminum-silicon coated plates, comprising a flux and a welding skin;

[0008] The filling rate of the flux in the solder skin is 20-35%;

[0009] The flux comprises the following components by mass:

[0010] 30-40 parts of iron powder, 3-11 parts of manganese powder, 5-9 parts of chromium powder, 4-6 parts of nickel powder, 6-12 parts of modified hexagonal boron nitride, 3-5 parts of titanium powder, 4-10 parts of copper powder, 1-5 parts of rhenium oxide powder;

[0011] The preparation method of the modified hexagonal boron nitride comprises the following steps:

[0012] S101, ultrasonically dispersing hexagonal boron nitride in 20wt% hydrogen peroxide for 0.5-2h, centrifugally filtering, washing the filtered product with sufficient deionized water and drying at room temperature, ultrasonically dispersing the filtered and dried product in 0.4-0.8wt% polyvinyl alcohol aqueous solution for 1-2h, rotary evaporating to remove water, and ball milling for 5-12h to obtain pretreated hexagonal boron nitride;

[0013] S102, placing the pretreated hexagonal boron nitride in step S101 into an autoclave filled with carbon dioxide for 1-3 hours to obtain hexagonal boron nitride loaded with carbon dioxide;

[0014] S103, ultrasonically dispersing the hexagonal boron nitride loaded with carbon dioxide obtained in step S102 into deionized water to obtain solution A, and adding styrene monomer and sodium hexadecyl sulfate into a mixed solution of deionized water and ethanol to obtain solution B;

[0015] S104, slowly adding the B solution in step S103 to the A solution and then adding potassium persulfate, stirring the reaction at 40-50° C. for 1-2 hours, then centrifuging and filtering, washing the filtered product with sufficient deionized water and then drying at room temperature to obtain modified hexagonal boron nitride.

[0016] Furthermore, in step S101, the mass ratio of hexagonal boron nitride, hydrogen peroxide and polyvinyl alcohol aqueous solution is 1:(30-45):(25-35).

[0017] Furthermore, in step S102, the pressure in the autoclave is 1-10 MPa.

[0018] Furthermore, the mass ratio of the hexagonal boron nitride loaded with carbon dioxide to deionized water in the solution A is 1:(30-40), and the mass ratio of the sodium hexadecyl sulfate, styrene monomer, deionized water and ethanol in the solution B to the hexagonal boron nitride loaded with carbon dioxide in the solution A is 1:(10-20):(60-70):(200-300):(6-10).

[0019] Furthermore, the mass ratio between the potassium persulfate in step S104 and the styrene monomer in step S103 is 1:(20-60).

[0020] Furthermore, in step S104, during the mixing reaction of solution A and solution B, carbon dioxide gas is continuously introduced into the mixed solution.

[0021] A method for preparing welding wire for laser welding of aluminum-silicon coated plates comprises the following steps:

[0022] S1. Mix iron powder, manganese powder, chromium powder, nickel powder, modified hexagonal boron nitride, titanium powder, copper powder and rhenium oxide powder in a mass ratio to obtain a flux;

[0023] S2, rolling the weld skin into a structure with a U-shaped groove by a forming machine, filling the flux in step S1 into the U-shaped groove of the weld skin, and then rolling and closing the U-shaped groove of the weld skin by a forming machine to obtain a weld skin filled with flux;

[0024] S3, drawing the weld skin filled with flux in step S2 to obtain welding wire for laser welding of aluminum-silicon coated plates.

[0025] Furthermore, the thickness of the weld skin in step S2 is 0.3 mm, and the composition of the weld skin includes 0.8 wt % carbon, 0.15 wt % manganese, 0.2 wt % silicon, 0.01 wt % sulfur, 0.02 wt % phosphorus, 0.08 wt % niobium, and the remainder is iron and unavoidable impurities in terms of mass percentage.

[0026] Furthermore, the diameter of the welding wire for laser welding of the aluminum-silicon coated plate drawn in step S3 is 1.6 mm.

[0027] The above-mentioned welding wire for laser welding of aluminum-silicon coated plates is used in welding of aluminum-silicon coated plates.

[0028] The above-mentioned welding wire for laser welding of aluminum-silicon coated plates is used in welding of aluminum-silicon coated plates.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The modified hexagonal boron nitride in the present invention captures carbon dioxide, and when the welding wire melts, it can release the captured carbon dioxide from the molten pool, thereby protecting the molten pool and ensuring the quality of the formed weld;

[0031] 2. In the present invention, polystyrene is synthesized on the outer surface of hexagonal boron nitride by an emulsion method, and the polystyrene is coated on the outer surface of the boron nitride, thereby reducing the escape of the shielding gas loaded by the modified hexagonal boron nitride before welding, and improving the protection ability of the shielding gas to the molten pool;

[0032] 3. The nickel, chromium and manganese elements of the flux of the present invention are combined with aluminum to avoid the production of brittle iron-aluminum metal parts compounds. At the same time, the modified boron nitride can decompose the boron and nitrogen elements, further improving the comprehensive mechanical properties of quilting. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The process flow chart of preparing welding wire for laser welding of aluminum-silicon coated plates according to the present invention;

[0034] Figure 2 The present invention is a process flow chart for preparing modified hexagonal boron nitride. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figure 1 to Figure 2 , the present invention provides a technical solution:

[0037] Embodiment 1:

[0038] A method for preparing welding wire for laser welding of aluminum-silicon coated plates comprises the following steps:

[0039] S1, 36g of iron powder, 10g of manganese powder, 6g of chromium powder, 5g of nickel powder, 11g of modified hexagonal boron nitride, 4g of titanium powder, 8g of copper powder, and 3g of rhenium oxide powder were mixed uniformly to obtain flux;

[0040] S2, rolling the weld skin into a structure with a U-shaped groove by a forming machine, filling the flux in step S1 into the U-shaped groove of the weld skin at a filling rate of 25%, and then rolling and closing the U-shaped groove of the weld skin by a forming machine to obtain a weld skin filled with flux;

[0041] S3. Pull the welding skin filled with flux in step S2 to obtain welding wire for laser welding of aluminum-silicon coated plates, and the diameter of the welding wire is 1.6 mm.

[0042] The preparation method of the modified hexagonal boron nitride comprises the following steps:

[0043] S101, ultrasonically dispersing 18 g of hexagonal boron nitride into 700 g of 20 wt% hydrogen peroxide and immersing for 1.4 h, centrifugally filtering, washing the filtered product with sufficient deionized water and drying at room temperature, ultrasonically dispersing the filtered and dried product into 540 g of 0.6 wt% polyvinyl alcohol aqueous solution for 1.8 h, removing water by rotary evaporation, and ball milling for 11 h to obtain pretreated hexagonal boron nitride;

[0044] S102, placing the pretreated hexagonal boron nitride in step S101 into an autoclave filled with carbon dioxide for 2.2 hours to obtain hexagonal boron nitride loaded with carbon dioxide, the pressure in the autoclave being 5 MPa;

[0045] S103, ultrasonically dispersing 16 g of hexagonal boron nitride loaded with carbon dioxide obtained in step S102 into 550 g of deionized water to obtain solution A, with an ultrasonic frequency of 50 kHz, and adding 28 g of styrene monomer and 2 g of sodium hexadecyl sulfate into a mixed solution of 130 g of deionized water and 450 g of ethanol to obtain solution B;

[0046] S104, slowly adding the B solution in step S103 to the A solution, and then adding 1.2 g of potassium persulfate, stirring the reaction at 48° C. for 1.6 h, continuously introducing carbon dioxide gas during the reaction, and then centrifugally filtering, washing the filtered product with sufficient deionized water and then drying it at room temperature to obtain modified hexagonal boron nitride.

[0047] Embodiment 2:

[0048] A method for preparing welding wire for laser welding of aluminum-silicon coated plates comprises the following steps:

[0049] S1, 45 g of iron powder, 4.5 g of manganese powder, 7.5 g of chromium powder, 6 g of nickel powder, 9 g of modified hexagonal boron nitride, 4.5 g of titanium powder, 6 g of copper powder, and 1.5 g of rhenium oxide powder were uniformly mixed to obtain a flux;

[0050] S2, rolling the weld skin into a structure with a U-shaped groove by a forming machine, filling the flux in step S1 into the U-shaped groove of the weld skin at a filling rate of 20%, and the filling rate of the flux in the weld skin is 30%, and then rolling and closing the U-shaped groove of the weld skin by a forming machine to obtain a weld skin filled with flux;

[0051] S3. Pull the welding skin filled with flux in step S2 to obtain welding wire for laser welding of aluminum-silicon coated plates, and the diameter of the welding wire is 1.6 mm.

[0052] The preparation method of the modified hexagonal boron nitride comprises the following steps:

[0053] S101, ultrasonically dispersing 16 g of hexagonal boron nitride into 480 g of 20 wt% hydrogen peroxide for 0.5 h, centrifugally filtering, washing the filtered product with sufficient deionized water and drying at room temperature, ultrasonically dispersing the filtered and dried product into 400 g of 0.4 wt% polyvinyl alcohol aqueous solution for 1 h, removing water by rotary evaporation, and ball milling for 5 h to obtain pretreated hexagonal boron nitride;

[0054] S102, placing the pretreated hexagonal boron nitride in step S101 into an autoclave filled with carbon dioxide for 1 hour to obtain hexagonal boron nitride loaded with carbon dioxide, the pressure in the autoclave being 1 MPa;

[0055] S103, ultrasonically dispersing 12 g of hexagonal boron nitride loaded with carbon dioxide obtained in step S102 into 360 g of deionized water to obtain solution A, with an ultrasonic frequency of 40 kHz, and adding 20 g of styrene monomer and 2 g of sodium hexadecyl sulfate into a mixed solution of 120 g of deionized water and 400 g of ethanol to obtain solution B;

[0056] S104, slowly adding the B solution in step S103 to the A solution, and then adding 1 g of potassium persulfate, stirring and reacting at 40-50° C. for 1 hour, continuously introducing carbon dioxide gas during the reaction, and then centrifugally filtering, washing the filtered product with sufficient deionized water and then drying it at room temperature to obtain modified hexagonal boron nitride.

[0057] Embodiment 3:

[0058] A method for preparing welding wire for laser welding of aluminum-silicon coated plates comprises the following steps:

[0059] S1, 40 g of iron powder, 11 g of manganese powder, 9 g of chromium powder, 6 g of nickel powder, 12 g of modified hexagonal boron nitride, 5 g of titanium powder, 10 g of copper powder, and 5 g of rhenium oxide powder were uniformly mixed to obtain a flux;

[0060] S2, rolling the weld skin into a structure with a U-shaped groove by a forming machine, filling the flux in step S1 into the U-shaped groove of the weld skin at a filling rate of 35%, and the filling rate of the flux in the weld skin is 45%, and then rolling and closing the U-shaped groove of the weld skin by a forming machine to obtain a weld skin filled with flux;

[0061] S3. Pull the welding skin filled with flux in step S2 to obtain welding wire for laser welding of aluminum-silicon coated plates, and the diameter of the welding wire is 1.6 mm.

[0062] The preparation method of the modified hexagonal boron nitride comprises the following steps:

[0063] S101, ultrasonically dispersing 18 g of hexagonal boron nitride into 700 g of 20 wt% hydrogen peroxide and immersing for 2 h, centrifugally filtering, washing the filtered product with sufficient deionized water and drying at room temperature, ultrasonically dispersing the filtered and dried product into 630 g of 0.8 wt% polyvinyl alcohol aqueous solution for 2 h, removing water by rotary evaporation, and ball milling for 12 h to obtain pretreated hexagonal boron nitride;

[0064] S102, placing the pretreated hexagonal boron nitride in step S101 into an autoclave filled with carbon dioxide for 3 hours to obtain hexagonal boron nitride loaded with carbon dioxide, the pressure in the autoclave being 10 MPa;

[0065] S103, ultrasonically dispersing 16 g of hexagonal boron nitride loaded with carbon dioxide obtained in step S102 into 640 g of deionized water to obtain solution A, with an ultrasonic frequency of 40 kHz, and adding 32 g of styrene monomer and 1.6 g of sodium hexadecyl sulfate into a mixed solution of 112 g of deionized water and 480 g of ethanol to obtain solution B;

[0066] S104, slowly adding the B solution in step S103 into the A solution, and then adding 0.53 g of potassium persulfate, stirring and reacting at 50° C. for 2 h, continuously introducing carbon dioxide gas during the reaction, and then centrifugally filtering, washing the filtered product with sufficient deionized water and then drying at room temperature to obtain modified hexagonal boron nitride.

[0067] Embodiment 4:

[0068] A method for preparing welding wire for laser welding of aluminum-silicon coated plates comprises the following steps:

[0069] S1, 38 g of iron powder, 8 g of manganese powder, 6 g of chromium powder, 6 g of nickel powder, 10 g of modified hexagonal boron nitride, 5 g of titanium powder, 8 g of copper powder, and 4 g of rhenium oxide powder were uniformly mixed to obtain a flux;

[0070] S2, rolling the weld skin into a structure with a U-shaped groove by a forming machine, filling the flux in step S1 into the U-shaped groove of the weld skin at a filling rate of 30%, and the filling rate of the flux in the weld skin is 40%, and then rolling and closing the U-shaped groove of the weld skin by a forming machine to obtain a weld skin filled with flux;

[0071] S3. Pull the welding skin filled with flux in step S2 to obtain welding wire for laser welding of aluminum-silicon coated plates, and the diameter of the welding wire is 1.6 mm.

[0072] The preparation method of the modified hexagonal boron nitride comprises the following steps:

[0073] S101, ultrasonically dispersing 18 g of hexagonal boron nitride into 600 g of 20 wt% hydrogen peroxide and immersing for 0.8 h, centrifugally filtering, washing the filtered product with sufficient deionized water and drying at room temperature, ultrasonically dispersing the filtered and dried product into 570 g of 0.5 wt% polyvinyl alcohol aqueous solution for 1.2 h, removing water by rotary evaporation, and ball milling for 7 h to obtain pretreated hexagonal boron nitride;

[0074] S102, placing the pretreated hexagonal boron nitride in step S101 into an autoclave filled with carbon dioxide for 1-3 hours to obtain hexagonal boron nitride loaded with carbon dioxide, the pressure in the autoclave being 8 MPa;

[0075] S103, ultrasonically dispersing 16 g of hexagonal boron nitride loaded with carbon dioxide obtained in step S102 into 500 g of a deionized water solution to obtain a solution A, with an ultrasonic frequency of 40 kHz, and adding 36 g of styrene monomer and 2 g of sodium hexadecyl sulfate into a mixed solution of 130 g of deionized water and 500 g of ethanol to obtain a solution B;

[0076] S104, slowly adding the B solution in step S103 into the A solution, then adding 1.6 g of potassium sulfate, stirring the reaction at 50° C. for 1.4 h, continuously introducing carbon dioxide gas during the reaction, then centrifugally filtering, washing the filtered product with sufficient deionized water and then drying it at room temperature to obtain modified hexagonal boron nitride.

[0077] Comparative Example 1

[0078] The difference between Comparative Example 1 and Example 1 is that step S102 is completely omitted, and the process of introducing carbon dioxide into the mixed solution in step S104 is omitted. The remaining steps are exactly the same as those in Example 1.

[0079] Comparative Example 2

[0080] The difference between Comparative Example 2 and Example 1 is that step S103 and step S104 are completely omitted, and the remaining steps are exactly the same as those in Example 1.

[0081] Comparative Example 3

[0082] The difference between Comparative Example 3 and Example 1 is that the hexagonal boron nitride used in step S101 is directly added in step S1, and the remaining steps are exactly the same as those in Example 1.

[0083] The thickness of the weld skin selected in the above embodiment is 0.3 mm, and the composition of the weld skin includes 0.8 wt % carbon, 0.15 wt % manganese, 0.2 wt % silicon, 0.01 wt % sulfur, 0.02 wt % phosphorus, 0.08 wt % niobium, and the balance is iron and unavoidable impurities;

[0084] In the above embodiment, the average particle size of the iron powder, manganese powder, chromium powder, nickel powder, titanium powder, copper powder and rhenium oxide powder is 150 μm, and the particle size of the hexagonal boron nitride used for modification in the present invention is 800 nm.

[0085] Welding experiments were performed on the welding wires prepared in Examples 1-4 and Comparative Examples 1-3:

[0086] Select an aluminum-silicon coated plate, which includes a substrate and a coating;

[0087] The thickness of the substrate is 3 mm, and the composition of the substrate includes, by mass percentage, 0.5 wt % silicon, 1.8 wt % manganese, 0.32 wt % carbon, 0.02 wt % phosphorus, 0.05 wt % sulfur, 0.3 wt % aluminum, 0.82 wt % chromium, 0.24 wt % titanium, and the balance is iron and unavoidable impurities;

[0088] The coating thickness is 20um, and the coating composition includes, by mass percentage: 88wt% aluminum, 11wt% silicon, and the remainder is iron and unavoidable impurities;

[0089] The specific welding process of the welding wire prepared in Examples 1-4 and Comparative Examples 1-3 is as follows:

[0090] Two aluminum-silicon coated plates were spliced ​​together, the weld gap between the two aluminum-silicon coated plates was 0.2 mm, and laser welding was performed. The laser power was 6000 W, the laser welding speed was 60 mm / s, the wire feeding speed was 60 mm / s, and the wire was preheated at 180°C before feeding. After the two aluminum-silicon coated plates were welded, they were kept at 850°C for 6 minutes, and then put into water at a temperature of 20°C for quenching for 20 seconds to obtain the welded aluminum-silicon coated plates (this welding process includes the first welding of the welding wire in comparative example 2);

[0091] In addition, the welding wire prepared in Comparative Example 2 was selected to perform the second, third and fourth welding on the same aluminum-silicon coated plate using the following method:

[0092] The second welding process is as follows:

[0093] Two aluminum-silicon coated plates were spliced ​​together, the weld gap between the two aluminum-silicon coated plates was 0.2 mm, and laser welding was performed. The laser welding power was 6000 W, the laser welding speed was 60 mm / s, the wire feeding speed was 60 mm / s, and the wire was not preheated before feeding. After the two aluminum-silicon coated plates were welded, they were kept at 850°C for 6 minutes, and then put into water at 20°C for quenching for 20 seconds to obtain the welded aluminum-silicon coated plates.

[0094] The third welding process is as follows:

[0095] Two aluminum-silicon coated plates were spliced ​​together, the weld gap between the two aluminum-silicon coated plates was 0.2 mm, and laser welding was performed. The laser welding power was 6000 W, the laser welding speed was 45 mm / s, the wire feeding speed was 45 mm / s, and the welding wire was not preheated before feeding. After the two aluminum-silicon coated plates were welded, they were kept at 850°C for 6 minutes, and then put into water at a temperature of 20°C for quenching for 20 seconds to obtain the welded aluminum-silicon coated plates.

[0096] The fourth welding process is as follows:

[0097] Two aluminum-silicon coated plates were spliced ​​together, the weld gap between the two aluminum-silicon coated plates was 0.2 mm, and laser welding was performed. The power of laser welding was 6000 W, the speed of laser welding was 30 mm / s, the wire feeding speed of welding wire was 30 mm / s, and the welding wire was not preheated before wire feeding. After the two aluminum-silicon coated plates were welded, they were kept at 850°C for 6 minutes, and then put into water at a temperature of 20°C for quenching for 20 seconds to obtain the welded aluminum-silicon coated plates.

[0098] A total of 10 welded aluminum-silicon coated plates were obtained by welding the welding wires prepared in the above Examples 1-4 and Comparative Examples 1-3 (including three additional welding tests of the welding wire prepared in Comparative Example 2). The welds of the 10 welded aluminum-silicon coated plates were tested for performance in accordance with the GB / T 228.1-2021 standard. The test results are shown in Table 1 below:

[0099] Table 1: Examples 1-4 and Comparative Example 1

[0100] Yield strength (MPa) Tensile strength(MPa) Elongation(%) Example 1 1284 1625 7.4 Example 2 1225 1594 6.9 Example 3 1261 1578 7.1 Example 4 1314 1616 7.2 Comparative Example 1 1092 1438 6.1 Comparative Example 2: First Welding 1151 1485 6.5 Comparative Example 2 Second Welding 1061 1377 6.0 Comparative Example 2 The third welding 1211 1554 6.8 Comparative Example 2 Fourth Welding 1226 1561 7.1 Comparative Example 3 1046 1396 5.8

[0101] By comparing Example 1 with Comparative Example 1, it can be seen that after the lack of carbon dioxide load, due to the lack of shielding gas load, the self-protection performance of the welding wire decreases, and the weld strength (yield strength, tensile strength and elongation) of the welded weld is significantly reduced. By comparing the first welding of the welding wire of Example 1 and Comparative Example 2, it can be seen that after the lack of the subsequent polystyrene synthesis step, the strength of the weld is also significantly reduced. The data of the first welding of the welding wire of Comparative Example 2 is compared with that of Comparative Example 1 (the weld strength of the first welding of the welding wire of Comparative Example 2 is still stronger than that of Comparative Example 1, which proves that it is still There is carbon dioxide to protect the welding process, but the protective effect is poorer than that in Example 1); We speculate that it may be that the synthetic polystyrene coats the surface of the boron nitride, reducing the escape of carbon dioxide loaded in the modified hexagonal boron nitride before welding (the escape of carbon dioxide includes the escape of protective gas on the surface of the modified hexagonal boron nitride caused by the preheating of the welding wire before welding, and during preheating, the escape of carbon dioxide in the modified hexagonal boron nitride is more), which improves the self-protection function of the welding wire;

[0102] At the same time, we conducted another three welding experiments using the welding wire prepared in Comparative Example 2. Compared with the first welding of the welding wire in Comparative Example 2, the welding speed and wire feeding speed of the second welding of the welding wire in Comparative Example 2 were the same, and the preheating of the welding wire was cancelled. The weld strength of the second welding of the welding wire in Comparative Example 2 was weaker than that of the first welding of the welding wire in Comparative Example 2. This is because the cancellation of preheating reduces the escape of carbon dioxide, but requires more laser energy to heat the welding wire. At this time, if the wire feeding speed of the first welding is still maintained, the melting effect of the welding wire is poor, resulting in a decrease in the quilting strength. Compared with the second welding of the welding wire in Comparative Example 2, the welding speed and wire feeding speed of the third welding of the welding wire in Comparative Example 2 were reduced, and the strength was significantly improved. This is because the preheating was cancelled and the slower At the wire feeding speed, the laser can heat and melt the welding wire better, and at the same time, the welding wire preheating process is cancelled and the escape of carbon dioxide loaded in the modified hexagonal boron nitride is reduced, so that the weld strength is significantly improved; in the fourth welding of the welding wire of Example 2 and the third welding of the welding wire of Example 2, the welding speed and the wire feeding speed are further reduced. Although the weld strength is improved, the improvement is not obvious compared with the improvement from the second welding to the third welding. Although the slower speed here can ensure that the hexagonal boron nitride that is not coated with polystyrene in the present invention can play a role in promoting the improvement of the weld strength, the welding wire preheating itself has the function of reducing stress and improving the quilting strength, the weld strength of the fourth welding of the welding wire of Example 2 is still lower than the weld strength in Example 1.

[0103] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A welding wire for laser welding of aluminum-silicon coated plates, characterized in that: Including flux and solder paste; The filling rate of the flux in the solder skin is 20-35%; The flux comprises the following components by mass: 30-40 parts of iron powder, 3-11 parts of manganese powder, 5-9 parts of chromium powder, 4-6 parts of nickel powder, 6-12 parts of modified hexagonal boron nitride, 3-5 parts of titanium powder, 4-10 parts of copper powder, 1-5 parts of rhenium oxide powder; The preparation method of the modified hexagonal boron nitride comprises the following steps: S101, ultrasonically dispersing hexagonal boron nitride in 20wt% hydrogen peroxide for 0.5-2h, centrifugally filtering, washing the filtered product with sufficient deionized water and drying at room temperature, ultrasonically dispersing the filtered and dried product in 0.4-0.8wt% polyvinyl alcohol aqueous solution for 1-2h, rotary evaporating to remove water, and ball milling for 5-12h to obtain pretreated hexagonal boron nitride; S102, placing the pretreated hexagonal boron nitride in step S101 into an autoclave filled with carbon dioxide for 1-3 hours to obtain hexagonal boron nitride loaded with carbon dioxide; S103, ultrasonically dispersing the hexagonal boron nitride loaded with carbon dioxide obtained in step S102 into deionized water to obtain solution A, and adding styrene monomer and sodium hexadecyl sulfate into a mixed solution of deionized water and ethanol to obtain solution B; S104, slowly adding the B solution in step S103 to the A solution and then adding potassium persulfate, stirring the reaction at 40-50° C. for 1-2 hours, then centrifuging and filtering, washing the filtered product with sufficient deionized water and then drying at room temperature to obtain modified hexagonal boron nitride.

2. The welding wire for laser welding of aluminum-silicon coated plates according to claim 1, characterized in that: In the step S101, the mass ratio of hexagonal boron nitride, hydrogen peroxide and polyvinyl alcohol aqueous solution is 1:(30-45):(25-35).

3. The welding wire for laser welding of aluminum-silicon coated plates according to claim 1, characterized in that: The pressure in the autoclave in step S102 is 1-10 MPa.

4. The welding wire for laser tailor welding of aluminum-silicon coated plates according to claim 1, characterized in that: The mass ratio of the hexagonal boron nitride loaded with carbon dioxide to deionized water in the solution A is 1:(30-40), and the mass ratio of the sodium hexadecyl sulfate, styrene monomer, deionized water and ethanol in the solution B to the hexagonal boron nitride loaded with carbon dioxide in the solution A is 1:(10-20):(60-70):(200-300):(6-10).

5. The welding wire for laser tailor welding of aluminum-silicon coated plates according to claim 1, characterized in that: The mass ratio of potassium persulfate in step S104 to the styrene monomer in step S103 is 1:(20-60).

6. The welding wire for laser tailor welding of aluminum-silicon coated plates according to claim 1, characterized in that: In the step S104, during the mixing reaction of solution A and solution B, carbon dioxide gas is continuously introduced into the mixed solution.

7. A method for preparing a welding wire for laser welding of aluminum-silicon coated plates according to any one of claims 1 to 6, characterized in that: The steps include: S1. Mix iron powder, manganese powder, chromium powder, nickel powder, modified hexagonal boron nitride, titanium powder, copper powder and rhenium oxide powder in a mass ratio to obtain a flux; S2, rolling the weld skin into a structure with a U-shaped groove by a forming machine, filling the flux in step S1 into the U-shaped groove of the weld skin, and then rolling and closing the U-shaped groove of the weld skin by a forming machine to obtain a weld skin filled with flux; S3, drawing the weld skin filled with flux in step S2 to obtain welding wire for laser welding of aluminum-silicon coated plates.

8. The method for preparing welding wire for laser welding of aluminum-silicon coated plates according to claim 7, characterized in that: The thickness of the weld skin in step S2 is 0.3 mm, and the composition of the weld skin includes, by mass percentage, 0.8 wt % carbon, 0.15 wt % manganese, 0.2 wt % silicon, 0.01 wt % sulfur, 0.02 wt % phosphorus, 0.08 wt % niobium, and the remainder is iron and unavoidable impurities.

9. The method for preparing welding wire for laser welding of aluminum-silicon coated plates according to claim 7, characterized in that: The diameter of the welding wire for laser welding of the aluminum-silicon coated plate drawn in step S3 is 1.6 mm.

10. Use of the welding wire for laser welding of aluminum-silicon coated plates as described in any one of claims 1 to 6 in welding of aluminum-silicon coated plates.

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