Method of making a welded joint, welding wire, welded joint

Abstract

This application relates to a method for preparing a welded joint, a welding wire, and a welded joint. The preparation method includes the following steps: S1, welding the welding wire to be adjusted to the base material to prepare a welded joint to be adjusted, and determining the dilution rate of the weld in the welded joint to be adjusted; S2, formulating a composition adjustment scheme for the welding wire to be adjusted; S3, preparing a weld simulation sample according to the dilution rate of the weld in the welded joint to be adjusted and the composition adjustment scheme for the welding wire to be adjusted; S4, measuring the self-corrosion potential difference between the weld simulation sample and the base material, and determining whether the self-corrosion potential difference is within the target potential difference range: if the self-corrosion potential difference is within the target potential difference range, preparing a target welding wire according to the composition adjustment scheme for the welding wire to be adjusted, and welding the target welding wire to the base material to prepare a target welded joint; if the self-corrosion potential difference is outside the target potential difference range, returning to step S2. The above preparation method can improve the corrosion resistance of the welded joint.

Description

Technical Field

[0001] This application relates to the field of welding technology, and in particular to a method for preparing a welded joint, a welding wire, and a welded joint. Background Technology

[0002] Aluminum alloys are widely used in fusion welding products in industries such as automotive, shipbuilding, aerospace, and construction. The corrosion resistance of aluminum alloy welded joints has a significant impact on their service life.

[0003] Because the welding wire and the base material have different compositions, there is often a potential difference between the weld and the base material. Electrochemical corrosion is likely to occur in corrosive environments such as seawater, which leads to a significant decrease in the corrosion resistance of the welded joint.

[0004] Traditional techniques improve the corrosion resistance of welded joints by optimizing the welding wire composition, modifying the weld surface (such as milling, rolling, shot peening, laser impact, etc.), or applying a corrosion-resistant coating to the weld surface.

[0005] However, the optimization of welding wire composition is mostly aimed at standard welding wire types, which is difficult to apply to welding joints with arbitrary composition combinations or new material systems. Moreover, the development cycle is long and the cost is high. Surface modification processes have problems such as low surface stability, surface roughness and poor equipment accessibility. Coating protection methods are prone to insufficient adhesion. When local areas peel off, the corrosion pits in the local area of ​​the weld surface will expand rapidly, resulting in a significant deterioration of the corrosion resistance of the weld. Summary of the Invention

[0006] Therefore, it is necessary to provide a method for preparing a welded joint, a welding wire, and a welded joint to solve the above-mentioned technical problems.

[0007] A first aspect of this application provides a method for preparing a welded joint, the method comprising the following steps: S1, welding a welding wire to be adjusted to a base material to prepare a welded joint to be adjusted, and determining the dilution rate of the weld in the welded joint to be adjusted; S2, formulating a composition adjustment scheme for the welding wire to be adjusted; S3, preparing a weld simulation sample according to the dilution rate of the weld in the welded joint to be adjusted and the composition adjustment scheme for the welding wire to be adjusted; S4, measuring the self-corrosion potential difference between the weld simulation sample and the base material, and determining whether the self-corrosion potential difference is within the target potential difference range: if the self-corrosion potential difference is within the target potential difference range, preparing a target welding wire according to the composition adjustment scheme for the welding wire to be adjusted, and welding the target welding wire to the base material to prepare a target welded joint; if the self-corrosion potential difference is outside the target potential difference range, returning to step S2.

[0008] In some embodiments, in step S4, the target potential difference range includes a first target potential difference range and a second target potential difference range; wherein, the first target potential difference range is 0 mV to a mV, the second target potential difference range is 0 mV to b mV, and a <b。

[0009] In some embodiments, the step of determining whether the self-corrosion potential difference is within the target potential difference range specifically includes the following steps: if the self-corrosion potential difference is within the first target potential difference range, prepare the target welding wire according to the composition adjustment scheme of the welding wire to be adjusted, and weld the target welding wire to the base material to prepare the target weld joint; if the self-corrosion potential difference is outside the first target potential difference range but within the second target potential difference range, return to step S2, and in the revised composition adjustment scheme of the welding wire to be adjusted, the added alloying elements and their contents include the types and contents of the newly added alloying elements in the previous cycle; if the self-corrosion potential difference is outside the second target potential difference range, return to step S2, and in the revised composition adjustment scheme of the welding wire to be adjusted, the added alloying elements and their contents do not include the types and contents of the newly added alloying elements in the previous cycle.

[0010] In some implementations, a is 10 and b is 20.

[0011] In some embodiments, after step S1, the following step is also included: measuring the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted.

[0012] In some embodiments, the step of returning to step S2 in the first cycle further includes the following steps: comparing the self-corrosion potential difference of the first cycle with the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted: if the self-corrosion potential difference of the first cycle is less than or equal to the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted, the alloying elements and their contents added in the second cycle in the revised composition adjustment scheme of the welding wire to be adjusted include the types and contents of the alloying elements newly added in the first cycle; if the self-corrosion potential difference of the first cycle is greater than the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted, the alloying elements and their contents added in the second cycle in the revised composition adjustment scheme of the welding wire to be adjusted do not include the types and contents of the alloying elements newly added in the first cycle.

[0013] In some embodiments, in the Nth cycle, returning to step S2 further includes the following steps: comparing the self-corrosion potential difference of the Nth cycle with the self-corrosion potential difference of the (N-1)th cycle, where N≥2: if the self-corrosion potential difference of the Nth cycle is less than or equal to the self-corrosion potential difference of the (N-1)th cycle, in the revised composition adjustment scheme for the welding wire to be adjusted, the alloying elements and their contents added in the (N+1)th cycle include the types and contents of the alloying elements newly added in the Nth cycle; if the self-corrosion potential difference of the Nth cycle is greater than the self-corrosion potential difference of the (N-1)th cycle, in the revised composition adjustment scheme for the welding wire to be adjusted, the alloying elements and their contents added in the (N+1)th cycle do not include the types and contents of the alloying elements newly added in the Nth cycle.

[0014] In some embodiments, in step S1 or step S4, the welding method is metal consumable electrode inert gas shielded welding.

[0015] In some implementations, in step S1, the joint to be welded is a full penetration butt joint.

[0016] In some implementations, in step S1, the base material is a 6xxx series aluminum alloy.

[0017] In some implementations, in step S1, the welding wire to be adjusted is an aluminum alloy welding wire.

[0018] In some implementations, in step S3, the weld simulation sample is a cast sample.

[0019] A second aspect of this application provides a welding wire, which is a target welding wire prepared using the welding joint preparation method provided in the first aspect above.

[0020] A third aspect of this application provides a welded joint, which is a target welded joint prepared by the preparation method of the welded joint provided in the second aspect above.

[0021] Compared with traditional technologies, this application has at least the following beneficial effects:

[0022] The method for preparing welded joints provided in some embodiments of this application first determines the dilution rate of the weld in the weld joint to be adjusted through the weld joint to be adjusted prepared in step S1, thereby obtaining the compositional relationship between the welding wire and the weld in the weld joint. Based on the dilution rate parameter, after formulating the composition adjustment scheme of the welding wire to be adjusted in step S2, the weld composition corresponding to the composition adjustment scheme is quantitatively calculated in step S3, and a weld simulation sample is prepared accordingly. Finally, in step S4, the feasibility of the composition adjustment scheme of the welding wire to be adjusted is determined by measuring the electrochemical performance of the weld simulation sample, and it is decided whether to adopt the composition adjustment scheme or return to step S2 for a new round of iteration.

[0023] The above-mentioned method for preparing welded joints establishes a cyclic adjustment mechanism for the composition of welding wire in steps S2 to S4 based on the dilution rate parameter in step S1. This indirectly adjusts the composition of the weld until the self-corrosion potential difference between the weld and the base material is within the target potential difference range. During the cyclic adjustment process, the addition of alloying elements improves the strength and thickness of the weld surface corrosion resistance, enhances the ability of the weld and heat-affected zone to resist rapid deterioration of local pitting corrosion, and thus improves the overall corrosion resistance of the welded joint.

[0024] Furthermore, the above-mentioned preparation method optimizes the alloy composition of the weld itself, bringing the self-corrosion potential difference between the weld and the base metal into a preset target range, thus fundamentally solving the corrosion resistance problem of the welded joint. More importantly, this preparation method replaces the traditional physical welding test method with simulation verification, greatly shortening the R&D cycle for welding wire selection and corrosion resistance optimization, reducing costs, and improving the optimization efficiency of welded joint corrosion resistance. At the same time, the above-mentioned preparation method does not rely on any specific standard welding wire or base metal system, and has a wide range of applications. It is not only applicable to improving the corrosion resistance of various homogeneous and dissimilar metal welded joints and preparing corrosion-resistant welding wires, but also applicable to other situations requiring interface potential matching for improving the corrosion resistance of joints, such as cold joining of dissimilar metals.

[0025] Furthermore, the above preparation method, by preparing weld simulation samples, results in more uniform sample composition, reducing the measurement errors caused by the difficulty of weld sampling and the unevenness of alloying elements in conventional welding methods. This allows the electrochemical measurement results to more accurately reflect the corrosion resistance characteristics of the weld joint. Attached Figure Description

[0026] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0027] Figure 1 This is a schematic flowchart of a method for preparing a welded joint according to one embodiment of this application. Detailed Implementation

[0028] Reference will now be made to detailed embodiments of this application, one or more of which are described below. Each example is provided for explanation and not for limitation of this application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to this application without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0029] Therefore, this application is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of this application are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of this application.

[0030] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0031] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0032] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0033] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0034] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0035] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0036] The first aspect of this application provides a method for preparing a welded joint, such as... Figure 1 As shown, the preparation method includes the following steps:

[0037] S1. Weld the welding wire to be adjusted to the base material to prepare the welding joint to be adjusted, and determine the dilution rate of the weld in the welding joint to be adjusted.

[0038] S2. Develop a composition adjustment plan for the welding wire to be adjusted.

[0039] S3. Prepare a weld simulation sample based on the dilution rate of the weld in the joint to be adjusted and the composition adjustment scheme of the welding wire to be adjusted.

[0040] S4. Measure the self-corrosion potential difference between the simulated weld sample and the base material, and determine whether the self-corrosion potential difference is within the target potential difference range:

[0041] When the self-corrosion potential difference is within the target potential difference range, the target welding wire is prepared according to the composition adjustment scheme of the welding wire to be adjusted, and the target welding wire is welded to the base material to prepare the target weld joint;

[0042] If the self-corrosion potential difference is outside the target potential difference range, return to step S2.

[0043] The method for preparing welded joints provided in some embodiments of this application first determines the dilution rate of the weld in the weld joint to be adjusted through the weld joint to be adjusted prepared in step S1, thereby obtaining the compositional relationship between the welding wire and the weld in the weld joint. Based on the dilution rate parameter, after formulating the composition adjustment scheme of the welding wire to be adjusted in step S2, the weld composition corresponding to the composition adjustment scheme is quantitatively calculated in step S3, and a weld simulation sample is prepared accordingly. Finally, in step S4, the feasibility of the composition adjustment scheme of the welding wire to be adjusted is determined by measuring the electrochemical performance of the weld simulation sample, and it is decided whether to adopt the composition adjustment scheme or return to step S2 for a new round of iteration.

[0044] The above-mentioned method for preparing welded joints establishes a cyclic adjustment mechanism for the composition of welding wire in steps S2 to S4 based on the dilution rate parameter in step S1. This indirectly adjusts the composition of the weld until the self-corrosion potential difference between the weld and the base material is within the target potential difference range. During the cyclic adjustment process, the addition of alloying elements improves the strength and thickness of the weld surface corrosion resistance, enhances the ability of the weld and heat-affected zone to resist rapid deterioration of local pitting corrosion, and thus improves the overall corrosion resistance of the welded joint.

[0045] Furthermore, the above-mentioned preparation method optimizes the alloy composition of the weld itself, bringing the self-corrosion potential difference between the weld and the base metal into a preset target range, thus fundamentally solving the corrosion resistance problem of the welded joint. More importantly, this preparation method replaces the traditional physical welding test method with simulation verification, greatly shortening the R&D cycle for welding wire selection and corrosion resistance optimization, reducing costs, and improving the optimization efficiency of welded joint corrosion resistance. At the same time, the above-mentioned preparation method does not rely on any specific standard welding wire or base metal system, and has a wide range of applications. It is not only applicable to improving the corrosion resistance of various homogeneous and dissimilar metal welded joints and preparing corrosion-resistant welding wires, but also applicable to other situations requiring interface potential matching for improving the corrosion resistance of joints, such as cold joining of dissimilar metals.

[0046] Furthermore, the above preparation method, by preparing weld simulation samples, results in more uniform sample composition, reducing the measurement errors caused by the difficulty of weld sampling and the unevenness of alloying elements in conventional welding methods. This allows the electrochemical measurement results to more accurately reflect the corrosion resistance characteristics of the weld joint.

[0047] In this article, "self-corrosion potential difference" refers to the absolute value of the difference in self-corrosion potential between the weld or weld simulation sample and the base material.

[0048] In some implementations, in step S4, the target potential difference ranges from 0 mV to 20 mV.

[0049] In some implementations, in step S4, the target potential difference ranges from 0 mV to 10 mV.

[0050] In some embodiments, step S4 includes a first target potential difference range and a second target potential difference range. The first target potential difference range is from 0 mV to a mV, and the second target potential difference range is from 0 mV to b mV, where a... <b。

[0051] Thus, by setting two target potential difference ranges, the iterative results of the composition adjustment scheme of the welding wire to be adjusted can be evaluated more precisely.

[0052] In some embodiments, the step of determining whether the self-corrosion potential difference is within the target potential difference range specifically includes the following steps:

[0053] When the self-corrosion potential difference is within the range of the first target potential difference, the target welding wire is prepared according to the composition adjustment scheme of the welding wire to be adjusted, and the target welding wire is welded to the base material to prepare the target welded joint.

[0054] If the self-corrosion potential difference is outside the first target potential difference range but within the second target potential difference range, return to step S2, and in the revised composition adjustment plan for the welding wire to be adjusted, the added alloying elements and their contents include the types and contents of alloying elements newly added in the previous cycle.

[0055] If the self-corrosion potential difference is outside the range of the second target potential difference, return to step S2, and in the revised composition adjustment plan for the welding wire to be adjusted, the added alloying elements and their contents do not include the types and contents of alloying elements newly added in the previous cycle.

[0056] In this way, by setting two target potential difference ranges and based on the test data of self-corrosion potential difference, different adjustment strategies can be established for the composition adjustment scheme of the welding wire to be adjusted under different conditions, thereby reducing trial and error costs and improving R&D efficiency.

[0057] In some specific implementations, a is 10 and b is 20.

[0058] In some embodiments, after step S1, the preparation method further includes the following step: measuring the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted.

[0059] In some embodiments, during the first cycle, the process returns to step S2, and the preparation method further includes the following steps:

[0060] The self-corrosion potential difference of the first cycle is compared with the self-corrosion potential difference between the weld and the base material in the joint to be welded:

[0061] If the self-corrosion potential difference in the first cycle is less than or equal to the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted, the alloying elements and their contents added in the second cycle in the revised composition adjustment scheme of the welding wire to be adjusted include the types and contents of the alloying elements newly added in the first cycle.

[0062] If the self-corrosion potential difference in the first cycle is greater than the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted, the alloying elements and their contents added in the second cycle in the revised composition adjustment plan for the welding wire to be adjusted do not include the types and contents of the alloying elements newly added in the first cycle.

[0063] In this way, by comparing the self-corrosion potential difference of the first cycle with the self-corrosion potential difference between the weld and the base material in the joint to be adjusted, a corresponding adjustment strategy is established for the subsequent formulation of the composition adjustment scheme of the welding wire to be adjusted, thereby reducing trial and error costs and improving R&D efficiency.

[0064] In some embodiments, in the Nth cycle, the process returns to step S2, and the preparation method further includes the following steps:

[0065] Compare the self-corrosion potential difference of the Nth cycle with the self-corrosion potential difference of the (N-1)th cycle, where N≥2:

[0066] If the self-corrosion potential difference in the Nth cycle is less than or equal to the self-corrosion potential difference in the N-1th cycle, the alloying elements and their contents added in the N+1th cycle in the revised composition adjustment scheme for the welding wire to be adjusted include the types and contents of the alloying elements newly added in the Nth cycle.

[0067] If the self-corrosion potential difference in the Nth cycle is greater than that in the N-1th cycle, the alloying elements and their contents added in the N+1th cycle in the revised composition adjustment scheme for the welding wire to be adjusted do not include the types and contents of the alloying elements newly added in the Nth cycle.

[0068] In this way, by comparing the self-corrosion potential difference of the Nth cycle with the self-corrosion potential difference of the N-1th cycle, a corresponding adjustment strategy is established for the subsequent formulation of the composition adjustment scheme of the welding wire to be adjusted, thereby reducing trial and error costs and improving R&D efficiency.

[0069] In some embodiments, after step S1, the preparation method further includes the following steps:

[0070] Measure the self-corrosion current density of the weld joint to be adjusted, as well as the weld and base material in the weld joint.

[0071] In some embodiments, step S4, the preparation method further includes the following steps:

[0072] The self-corrosion current density of the weld was measured in a simulated weld sample.

[0073] Further, in step S4, the preparation method also includes the following steps:

[0074] The corrosion resistance of the weld simulation sample is evaluated by comparing the self-corrosion current density of the weld in the weld joint to be adjusted.

[0075] In some embodiments, the preparation method further includes the following steps:

[0076] Measure the self-corrosion current density of the target welded joint.

[0077] Further, in step S4, the preparation method also includes the following steps:

[0078] The corrosion resistance of the target weld joint is evaluated by comparing the self-corrosion current density of the target weld joint with the self-corrosion current density of the weld joint to be adjusted and the base material.

[0079] Thus, by introducing self-corrosion current density as a measurement index, the corrosion resistance of materials can be evaluated more comprehensively and accurately.

[0080] It is understood that this application does not limit the method for determining the dilution rate of the weld in the joint to be adjusted in step S1.

[0081] In some embodiments, the dilution rate of the weld in the joint to be welded is determined by the metallographic area method. The metallographic area method calculates the dilution rate by analyzing the metallographic image of the weld cross-section and measuring the ratio of the area formed by the melting of the base material to the total weld area.

[0082] In other embodiments, the dilution rate of the weld in the joint to be adjusted is determined by chemical composition analysis. Chemical composition analysis calculates the dilution rate (D) of the weld in the joint by accurately measuring the actual concentration of a tracer element in the weld region and combining this with the known concentrations of that element in the welding wire and base material. The formula is: D = (C 焊缝 -C 焊丝 ) / (C 母材 -C 焊丝 ).

[0083] In some implementations, step S2 specifically includes the following steps:

[0084] Alloying elements are added based on single-factor variables.

[0085] Thus, the single-factor variable method simplifies experimental design, establishes a causal relationship between a specific alloying element and its effect on the self-corrosion potential difference, makes the optimization process logically clear and easy to analyze, and reduces the uncertainty caused by multi-factor coupling.

[0086] In some implementations, step S2 further includes the following steps:

[0087] Add alloying elements in at least three content gradients.

[0088] In this way, by setting multiple content gradients, the optimal content of the selected alloying element can be determined.

[0089] In some implementations, step S3 specifically includes the following steps:

[0090] S31. Based on the dilution rate of the weld in the joint to be adjusted, the composition adjustment scheme of the welding wire to be adjusted, and the composition of the base material, calculate the simulated composition of the weld.

[0091] S32. Prepare a weld simulation sample based on the weld simulation composition.

[0092] It is understandable that the process of calculating the simulated weld composition in step S31 is based on the fundamental principle that the weld metal is formed by the fusion of the welding wire metal and the base metal during the welding process. The weld dilution rate (D) represents the mass percentage or volume percentage of the molten base metal in the entire weld metal.

[0093] Therefore, the final concentration (C) of any alloying element (i) in the weld is... 焊缝 (i) can be calculated using the following formula: C 焊缝 (i)=C 焊丝 (i)×(1-D)+C 母材 (i)×D.

[0094] Among them, C 焊缝 (i) represents the target composition content of element i in the weld (unit: wt%); C 焊丝 (i) The content (in wt%) of element i in the composition adjustment scheme of the welding wire to be adjusted as specified in step S2; C 母材 (i) is the content of element i in the known base material (unit: wt%); D is the weld dilution rate of the weld joint to be adjusted determined in step S1.

[0095] In some implementations, in step S1 or step S4, the welding method is metal arc welding (MIG welding).

[0096] In some implementations, in step S1, the joint to be welded is a full penetration butt joint.

[0097] In some implementations, in step S1, the base material is a 6xxx series aluminum alloy.

[0098] In some implementations, in step S1, the welding wire to be adjusted is an aluminum alloy welding wire.

[0099] In some implementations, in step S3, the weld simulation sample is a cast sample.

[0100] Thus, when the weld simulation sample is a cast sample, the preparation of the weld simulation sample can be achieved by using the small furnace casting method, which is time-saving, easy to operate, and speeds up the verification of the composition adjustment scheme. At the same time, during the casting process, the alloying elements are fully mixed in the liquid metal, resulting in good chemical homogeneity of the weld simulation sample and reducing the error of subsequent electrochemical tests.

[0101] A second aspect of this application provides a welding wire, which is a target welding wire prepared using the welding joint preparation method provided in the first aspect above.

[0102] A third aspect of this application provides a welded joint, which is a target welded joint prepared by the preparation method of the welded joint provided in the second aspect above.

[0103] A fourth aspect of this application provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements at least one step in the method for preparing a welded joint as described in any example of the first aspect of this application. This facilitates the rapid and efficient establishment of databases containing various types of high corrosion-resistant welding wire compositions, weld compositions, and welded joint properties, and provides data support for the development of corresponding simulation models and big data machine learning models.

[0104] The present application will be further described below with reference to specific embodiments and comparative examples.

[0105] Example 1

[0106] This embodiment provides a method for preparing a welded joint, a welding wire, and a welded joint.

[0107] (a) Prepare the welding joint to be adjusted and determine the weld dilution rate.

[0108] Commercially available 6082 (T6) aluminum alloy was selected as the base material, and commercially available ER4047 welding wire was used as the welding wire to be adjusted. The MIG welding process was used to prepare the weld joint to be adjusted without obvious welding defects. The corrosion potential of the base material, the weld and the weld joint to be adjusted were measured and the self-corrosion current density was calculated in sequence according to the electrochemical testing standards. The test results are shown in Table 1.

[0109] Table 1

[0110]

[0111] Table 1 shows that there is a self-corrosion potential difference of 47.7 mV between the weld and the base metal in the joint to be adjusted, indicating a high risk of corrosion. Simultaneously, the self-corrosion current density of the joint to be adjusted is 2.069*10⁻⁶. -6 A / cm 2 This is far higher than the self-corrosion current density of the base material, which is 1.7480*10. -7 A / cm 2 This indicates that its overall corrosion resistance is poor.

[0112] The cross-section of the aforementioned weld joint to be adjusted was analyzed by metallographic method, and the dilution rate D of the weld was calculated to be 53.13% under this welding process.

[0113] (ii) Iterative cycle for welding wire composition and weld composition.

[0114] In this embodiment, the target potential difference ranges from 0 mV to 20 mV.

[0115] First loop:

[0116] (1) Based on the composition of the welding wire ER4047 to be adjusted, a scheme for adding Mg element with different content gradients was formulated.

[0117] (2) Based on the dilution rate, base material composition, and composition adjustment scheme of each welding wire to be adjusted, use formula C 焊缝 (i)=C 焊丝 (i)×(1-D)+C 母材 (i)×D calculates the simulated composition of the weld, and based on the simulated composition of the weld, a casting sample is prepared by small furnace casting method, which is the simulated weld sample.

[0118] (3) According to the test, the self-corrosion potential difference between the simulated weld sample and the base material corresponding to the composition adjustment scheme of 2.8% Mg content in one group of welding wires was 30.46 mV, which was significantly lower than the self-corrosion potential difference of 47.7 mV between the weld and the base material in the weld joint to be adjusted, proving that adding Mg element is an effective optimization direction.

[0119] Second cycle:

[0120] (1) Based on the Mg element added in the first cycle (Mg content in the welding wire is 2.8% w%), an adjustment scheme for adding Cu element with different content gradients was formulated.

[0121] (2) Calculate the simulated composition of the weld according to the aforementioned formula, and prepare a casting sample by small furnace casting method based on the simulated composition of the weld, which is the simulated weld sample.

[0122] (3) The test results are shown in Table 2. The self-corrosion potential difference between the weld simulation sample and the base material corresponding to the composition adjustment scheme with 0.5% Cu content in the welding wire is 19.5 mV, which is lower than the 30.46 mV self-corrosion potential difference between the weld simulation sample and the base material in the first cycle and is within the target potential difference range. At the same time, the self-corrosion current density of the weld simulation sample is also significantly reduced.

[0123] Table 2

[0124]

[0125] (III) Preparation of target welding wire and target welded joint

[0126] The target welding wire was prepared according to the composition adjustment scheme of the welding wire to be adjusted in the second cycle, and the target welding wire was used to prepare a full penetration weld joint without obvious welding defects as the target welding joint. The self-corrosion current density of the target welding wire weld joint is shown in Table 3.

[0127] Table 3

[0128]

[0129] As shown in Table 3, the self-corrosion current density of the target welded joint is 4.9371*10. -7 A / cm 2 Compared to the 2.069×10⁻ welded joint to be adjusted 6 A / cm 2 The self-corrosion current density has been significantly reduced and is very close to that of the base material (1.7480 × 10⁻⁶). -7 The self-corrosion current of A / cm² proves that the welding joint preparation method in this embodiment successfully prepared a welding joint with excellent corrosion resistance.

[0130] Example 2

[0131] This embodiment provides a method for preparing a welded joint, a welding wire, and a welded joint.

[0132] (a) Prepare the welding joint to be adjusted and determine the weld dilution rate.

[0133] Commercially available 6082 (T6) aluminum alloy was selected as the base material, and commercially available ER5356 welding wire was used as the welding wire to be adjusted. The MIG welding process was used to prepare the weld joint to be adjusted without obvious welding defects. The corrosion potential of the base material, the weld and the weld joint to be adjusted were measured and the self-corrosion current density was calculated in sequence according to the electrochemical testing standards. The test results are shown in Table 4.

[0134] Table 4

[0135]

[0136] Table 4 shows that there is a self-corrosion potential difference of 32.7 mV between the weld and the base metal in the joint to be adjusted, indicating a high risk of corrosion. Simultaneously, the self-corrosion current density of the joint to be adjusted is 1.069*10⁻⁶ mV. -6 This is far higher than the self-corrosion current density of the base material, which is 1.7480*10. -7 This indicates that its overall corrosion resistance is poor.

[0137] The cross-section of the aforementioned weld joint to be adjusted was analyzed by metallographic method, and the dilution rate D of the weld was calculated to be 56.18% under this welding process.

[0138] (ii) Iterative cycle for welding wire composition and weld composition.

[0139] In this embodiment, the target potential difference range includes a first target range and a second target range. The first target range is 0 mV to 10 mV, and the second target range is 0 mV to 20 mV.

[0140] First loop:

[0141] (1) Based on the composition of the welding wire ER5356 to be adjusted, a scheme for adding Mg element with different content gradients was formulated.

[0142] (2) Based on the dilution rate, base material composition, and composition adjustment scheme of each welding wire to be adjusted, use formula C 焊缝 (i)=C 焊丝 (i)×(1-D)+C 母材 (i)×D calculates the simulated composition of the weld, and based on the simulated composition of the weld, a casting sample is prepared by small furnace casting method, which is the simulated weld sample.

[0143] (3) According to the test, the self-corrosion potential difference between the simulated weld sample and the base material corresponding to the composition adjustment scheme of 5.5% Mg content in one group of welding wires was 23.4 mV, which is lower than the self-corrosion potential difference of 32.7 mV between the weld and the base material in the weld joint to be adjusted, proving that adding Mg element is an effective optimization direction.

[0144] Second cycle:

[0145] (1) Based on the Mg element added in the first cycle (Mg content in the welding wire is 5.5%), an adjustment scheme for adding Mn element with different content gradients was formulated.

[0146] (2) Calculate the simulated composition of the weld according to the aforementioned formula, and prepare a casting sample by small furnace casting method based on the simulated composition of the weld, which is the simulated weld sample.

[0147] (3) According to the test, the self-corrosion potential difference between the weld simulation sample and the base material corresponding to the composition adjustment scheme of 0.65% Mn content in one group of welding wires was 16.42 mV, which was lower than the self-corrosion potential difference of 23.4 mV between the weld simulation sample and the base material in the first cycle and within the range of the second target potential difference, proving that adding Mn element on the basis of adding Mg element is an effective optimization direction.

[0148] Third cycle:

[0149] (1) Based on the Mg and Mn elements added in the second cycle (Mg content in the welding wire is 5.5% and Mn content is 0.65%), an adjustment scheme for adding Cu elements with different content gradients was formulated.

[0150] (2) Calculate the simulated composition of the weld according to the aforementioned formula, and prepare a casting sample by small furnace casting method based on the simulated composition of the weld, which is the simulated weld sample.

[0151] (3) The test results are shown in Table 5. In one group of welding wire composition adjustment schemes with 0.45% Cu content, the self-corrosion potential difference between the weld simulation sample and the base material was 5.5 mV, which was lower than the 23.4 mV self-corrosion potential difference between the weld simulation sample and the base material in the second cycle and was within the first target potential difference range. At the same time, the self-corrosion current density of the weld simulation sample was also significantly reduced.

[0152] Table 5

[0153]

[0154] (III) Preparation of target welding wire and target welded joint

[0155] The target welding wire was prepared according to the composition adjustment scheme of the welding wire to be adjusted in the third cycle, and the target welding wire was used to prepare a full penetration weld joint without obvious welding defects as the target welding joint. The self-corrosion current density of the target welding wire weld joint is shown in Table 6.

[0156] Table 6

[0157]

[0158] As shown in Table 6, the self-corrosion current density of the target welded joint is 3.8371*10. -7 A / cm 2 Compared to the 1.069*10 welded joint to be adjusted -6 A / cm 2 The self-corrosion current density has been significantly reduced and is very close to that of the base material (1.7480*10). -7 The self-corrosion current of A / cm² proves that the welding joint preparation method in this embodiment successfully prepared a welding joint with excellent corrosion resistance.

[0159] Comparative Example 1

[0160] This comparative example provides a method for preparing a welded joint, a welding wire, and a welded joint.

[0161] (a) Prepare the welding joint to be adjusted and determine the weld dilution rate.

[0162] In this comparative example, the welding wire to be adjusted, the base material, and the welding joint to be adjusted are the same as in Example 1.

[0163] (ii) Iterative cycle for welding wire composition and weld composition.

[0164] In this comparative example, the target potential difference ranges from 0 mV to 20 mV.

[0165] First loop:

[0166] (1) Based on the composition of the welding wire ER4047 to be adjusted, a scheme for adding Si elements with different content gradients was developed.

[0167] (2) Based on the dilution rate, base material composition, and composition adjustment scheme of each welding wire to be adjusted, use formula C 焊缝 (i)=C 焊丝 (i)×(1-D)+C 母材 (i)×D calculates the simulated composition of the weld, and based on the simulated composition of the weld, a casting sample is prepared by small furnace casting method, which is the simulated weld sample.

[0168] (3) According to the test, the self-corrosion potential difference between the weld simulation sample and the base material corresponding to the composition adjustment scheme of 7.5% Si content in one group of welding wires was 39.6 mV, which was significantly lower than the self-corrosion potential difference of 47.7 mV between the weld and the base material in the welding joint to be adjusted, proving that adding Si element is an effective optimization direction.

[0169] Second cycle:

[0170] (1) Based on the Si element added in the first cycle (the Si content in the welding wire is 7.5%), an adjustment scheme for adding Cu element with different content gradients was formulated.

[0171] (2) Calculate the simulated composition of the weld according to the aforementioned formula, and prepare a casting sample by small furnace casting method based on the simulated composition of the weld, which is the simulated weld sample.

[0172] (3) The test results are shown in Table 7. In one group of welding wire composition adjustment schemes with 0.8% Cu content, the self-corrosion potential difference between the simulated weld sample and the base material was 57 mV, which was not only outside the target range but also higher than the 39.6 mV in the first cycle. Therefore, it can be seen that the composition adjustment scheme of adding Cu on the basis of adding Si is an ineffective optimization path, and other elements should be selected for addition.

[0173] Table 7

[0174]

[0175] Comparative Example 2

[0176] (a) Prepare the welding joint to be adjusted and determine the weld dilution rate.

[0177] In this comparative example, the welding wire to be adjusted, the base material, and the welding joint to be adjusted are the same as in Example 2.

[0178] (ii) Iterative cycle for welding wire composition and weld composition.

[0179] In this comparative example, the target potential difference range includes a first target range and a second target range. The first target range is 0 mV to 10 mV, and the second target range is 0 mV to 20 mV.

[0180] First loop:

[0181] (1) Based on the composition of the welding wire ER5356 to be adjusted, a scheme for adding Si elements with different content gradients was developed.

[0182] (2) Based on the dilution rate, base material composition, and composition adjustment scheme of each welding wire to be adjusted, use formula C 焊缝 (i)=C 焊丝 (i)×(1-D)+C 母材 (i)×D calculates the simulated composition of the weld, and based on the simulated composition of the weld, a casting sample is prepared by small furnace casting method, which is the simulated weld sample.

[0183] (3) According to the test, the self-corrosion potential difference between the weld simulation sample and the base material corresponding to the composition adjustment scheme of 3.2% Si content in one group of welding wires was 28.4 mV, which is lower than the self-corrosion potential difference of 32.7 mV between the weld and the base material in the welding joint to be adjusted, proving that adding Si element is an effective optimization direction.

[0184] Second cycle:

[0185] (1) Based on the Si element added in the first cycle (the Si content in the welding wire is 3.2%), an adjustment scheme for adding Cu element with different content gradients was formulated.

[0186] (2) Calculate the simulated composition of the weld according to the aforementioned formula, and prepare a casting sample by small furnace casting method based on the simulated composition of the weld, which is the simulated weld sample.

[0187] (3) The test results are shown in Table 8. In one group of welding wire composition adjustment schemes with 0.93% Cu content, the self-corrosion potential difference between the simulated weld sample and the base material was 55 mV, which was not only outside the second target range, but also higher than the 28.4 mV in the first cycle. It can be seen that the composition adjustment scheme of adding Cu on the basis of adding Si is an ineffective optimization path, and other elements should be selected for addition.

[0188] Table 8

[0189]

[0190] Comparing Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2, it can be seen that not any combination of elements can be successful in adjusting the composition of the welding wire. The welding joint preparation methods provided in some embodiments of this application, through iterative cycles, electrochemical measurements, and judgment, can effectively identify and discard ineffective optimization paths, thereby reducing R&D costs and improving R&D efficiency.

[0191] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0192] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method of producing a welded joint, characterized in that Includes the following steps: S1. Weld the welding wire to be adjusted to the base material to prepare the welding joint to be adjusted, and determine the dilution rate of the weld in the welding joint to be adjusted. S2. Develop a composition adjustment plan for the welding wire to be adjusted; S3. Prepare a weld simulation sample according to the dilution rate of the weld in the joint to be adjusted and the composition adjustment scheme of the welding wire to be adjusted; S4. Measure the self-corrosion potential difference between the simulated weld sample and the base material, and determine whether the self-corrosion potential difference is within the target potential difference range: When the self-corrosion potential difference is within the target potential difference range, a target welding wire is prepared according to the composition adjustment scheme of the welding wire to be adjusted, and the target welding wire is welded to the base material to prepare a target weld joint; If the self-corrosion potential difference is outside the target potential difference range, return to step S2; Step S3 specifically includes the following steps: S31. Based on the dilution rate of the weld in the joint to be adjusted, the composition adjustment scheme of the welding wire to be adjusted, and the composition of the base material, calculate the simulated composition of the weld. S32. Prepare a weld simulation sample based on the simulated weld composition; In step S4, the target potential difference range includes a first target potential difference range and a second target potential difference range; Wherein, the first target potential difference ranges from 0 mV to a mV, the second target potential difference ranges from 0 mV to b mV, and a <b; The step of determining whether the self-corrosion potential difference is within the target potential difference range specifically includes the following steps: When the self-corrosion potential difference is within the range of the first target potential difference, a target welding wire is prepared according to the composition adjustment scheme of the welding wire to be adjusted, and the target welding wire is welded to the base material to prepare a target weld joint; If the self-corrosion potential difference is outside the first target potential difference range but within the second target potential difference range, return to step S2, and in the revised composition adjustment scheme of the welding wire to be adjusted, the added alloying elements and their contents include the types and contents of alloying elements newly added in the previous cycle. If the self-corrosion potential difference is outside the range of the second target potential difference, return to step S2, and in the revised composition adjustment scheme of the welding wire to be adjusted, the added alloying elements and their contents do not include the types and contents of alloying elements newly added in the previous cycle.

2. The method of producing a welded joint according to claim 1, characterized in that, a is 10, b is 20.

3. The method of producing a welded joint according to claim 1, characterized in that, Following step S1, the following steps are also included: Measure the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted.

4. The method of producing a welded joint according to claim 3, characterized in that, In the first loop, returning to the step of executing step S2 also includes the following steps: The self-corrosion potential difference of the first cycle is compared with the self-corrosion potential difference between the weld and the base material in the joint to be adjusted: If the self-corrosion potential difference in the first cycle is less than or equal to the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted, the alloying elements and their contents added in the second cycle in the revised composition adjustment scheme of the welding wire to be adjusted include the types and contents of the alloying elements newly added in the first cycle. If the self-corrosion potential difference in the first cycle is greater than the self-corrosion potential difference between the weld and the base material in the weld joint to be adjusted, the alloying elements and their contents added in the second cycle in the revised composition adjustment scheme of the welding wire to be adjusted do not include the types and contents of the alloying elements newly added in the first cycle.

5. The method of producing a welded joint according to claim 1, characterized in that, In the Nth iteration, returning to the step of executing step S2 also includes the following steps: Compare the self-corrosion potential difference of the Nth cycle with the self-corrosion potential difference of the (N-1)th cycle, where N≥2; If the self-corrosion potential difference in the Nth cycle is less than or equal to the self-corrosion potential difference in the N-1th cycle, in the revised composition adjustment scheme of the welding wire to be adjusted, the alloying elements and their contents added in the N+1th cycle include the types and contents of the alloying elements newly added in the Nth cycle. If the self-corrosion potential difference in the Nth cycle is greater than that in the (N-1)th cycle, the alloying elements and their contents added in the (N+1)th cycle in the revised composition adjustment scheme of the welding wire to be adjusted do not include the types and contents of the alloying elements newly added in the Nth cycle.

6. The method of producing a welded joint according to any one of claims 1 to 5, characterized in that, At least one of the following conditions must be met: (1) In step S1 or step S4, the welding method is metal consumable electrode inert gas shielded welding; (2) In step S1, the welding joint to be adjusted is a full penetration butt joint; (3) In step S1, the base material is a 6xxx series aluminum alloy; (4) In step S1, the welding wire to be adjusted is an aluminum alloy welding wire; (5) In step S3, the weld simulation sample is a cast sample.

7. A welding wire characterized by, The welding wire is the target welding wire prepared by the method for preparing a welding joint as described in any one of claims 1 to 6.

8. A welded joint, characterized by The target welded joint is prepared by the method for preparing welded joints as described in any one of claims 1 to 6.

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