Arcing welding method for magnesium alloy stud

Abstract

The invention relates to the technical field of arcing stud welding, in particular to a magnesium alloy stud arcing welding method. Comprising the following steps: preparing a magnesium alloy stud: selecting an AZ31 magnesium alloy or an AZ61 magnesium alloy as a preparation base material of the magnesium alloy stud, and molding and manufacturing; the welding spot position of the magnesium alloy product to be welded is subjected to surface cleaning; introducing high-purity inert gas for protection in the whole process; arc discharge welding process parameters are set, wherein the arc discharge welding process parameters comprise a protective gas conveying time parameter, an arc discharge welding current parameter and an arc discharge welding time parameter; and welding operation is conducted, specifically, the magnesium alloy stud and the cleaned magnesium alloy to-be-welded product are accurately positioned, the gas supply state of the introduced protective gas is maintained, arc discharge welding is conducted according to the set arc discharge welding technological parameters, and a welded finished product is obtained. Therefore, the technical problems that in the prior art, the pseudo soldering phenomenon occurs frequently, the connection reliability of a welding joint is seriously affected, and the actual use requirement of a magnesium alloy structural part cannot be met are solved.

Description

Technical Field

[0001] This application relates to the field of arc welding technology for studs, and more particularly to an arc welding method for magnesium alloy studs. Background Technology

[0002] Arc welding of studs is a highly efficient welding method that uses an electric arc to heat and apply pressure to quickly connect studs to metal sheets. It has advantages such as high welding efficiency, good joint stability, and high degree of automation. It is currently widely used in the automotive, rail transportation, aerospace, and electronics industries for connecting aluminum alloy products.

[0003] However, arc welding technology for magnesium alloy studs has not yet been developed and applied. Nevertheless, as the lightweight advantages of magnesium alloys become more prominent, their application in various structural components is becoming increasingly widespread. In practical use, magnesium alloy structural components often require the use of welded studs to achieve functions such as wire harness mounting, fixing cover parts, or connecting other accessories.

[0004] Currently, to meet the aforementioned welding requirements of magnesium alloy structural components, the industry can only use aluminum alloy studs to perform arc welding with magnesium alloy products. However, due to the significant differences between aluminum alloy and magnesium alloy in terms of melting point, thermal conductivity, coefficient of linear expansion, and chemical activity, incomplete fusion and poor interface bonding are prone to occur during welding, leading to frequent instances of cold welds. This severely affects the reliability of the welded joint and fails to meet the actual usage requirements of magnesium alloy structural components. Summary of the Invention

[0005] The purpose of this application is to provide a method for arc welding of magnesium alloy studs, so as to achieve reliable welding of magnesium alloy products and magnesium alloy studs, thereby solving the technical problem that the existing magnesium alloy products can only be arc welded with aluminum alloy studs, resulting in frequent false welds, which seriously affects the connection reliability of the welded joints and cannot meet the actual use requirements of magnesium alloy structural parts.

[0006] This application provides a method for arc welding of magnesium alloy studs, comprising the following steps: S10, prepare magnesium alloy studs, select AZ31 magnesium alloy or AZ61 magnesium alloy as the base material for preparing magnesium alloy studs and form them. S20, perform surface cleaning on the weld points of magnesium alloy products to be welded; S30, high-purity inert gas protection throughout the entire process, high-purity inert gas is introduced into the welding area between the magnesium alloy stud and the magnesium alloy product to be welded for full protection during the entire arc welding process. S40, set the arc welding process parameters, including shielding gas delivery time parameters, arc welding current parameters, and arc welding time parameters; S50, Welding operation: The magnesium alloy stud prepared in step S10 is precisely positioned with the magnesium alloy product to be welded after being cleaned in step S20, and the protective gas supply in step S30 is maintained. Arc welding is carried out according to the arc welding process parameters set in step S40 to obtain the welded product.

[0007] Furthermore, in step S40, the protective gas delivery time parameter is set to 900-1000ms, the arc welding current parameter is set to 650-800mA, and the arc welding time parameter is set to 11-13ms.

[0008] Furthermore, in step S20, the surface of the weld joint of the magnesium alloy product to be welded is cleaned with a special cleaning agent, which is one or more of organic solvent cleaning agents, weak alkaline composite cleaning agents, or weak acid complexing cleaning agents.

[0009] Furthermore, the organic solvent cleaning agent is one or more of anhydrous ethanol, isopropanol, and acetone.

[0010] Furthermore, in step S20, after cleaning is completed, step S11 is also included, in which anhydrous ethanol is used to wipe the solder joints of the magnesium alloy product to be welded to remove cleaning agent residue.

[0011] Furthermore, in step S30, the high-purity inert gas is high-purity argon, or a mixture of high-purity argon and high-purity helium.

[0012] Furthermore, the purity of the high-purity argon gas is ≥99.99%, and the purity of the high-purity helium gas is ≥99.99%.

[0013] Furthermore, if the high-purity inert gas is a mixture of high-purity argon and high-purity helium, then the volume percentage of high-purity helium in the mixture is 10% to 30%, with the remainder being high-purity argon.

[0014] Furthermore, after step S50, step S60 is also included: after welding is completed, torque test is performed on the welded joint between the obtained magnesium alloy stud and the magnesium alloy product to be welded to check whether the joint is reliably connected.

[0015] Furthermore, the magnesium alloy product to be welded is made of AZ91 magnesium alloy sheet.

[0016] Compared with existing technologies, the magnesium alloy stud arc welding method provided in this application firstly involves arc welding a magnesium alloy stud made from a base material of AZ31 or AZ61, which has similar physical properties to the base material of the magnesium alloy product to be welded. Since they are from the same material source, their melting points, thermal conductivity, and coefficients of thermal expansion are very close, reducing problems such as heat input mismatch caused by dissimilar materials and lowering the tendency to crack. Under the same welding parameters, the two can basically achieve synchronous melting and solidification, forming a good metallurgical bond with low thermal stress and less susceptibility to hot cracks caused by inconsistent expansion and contraction. This solves the problems of incomplete welding and poor bonding caused by welding magnesium alloy products with aluminum alloy studs in existing technologies, achieving a reliable connection between magnesium alloy products and magnesium alloy studs, while meeting the actual use requirements of magnesium alloy products.

[0017] Furthermore, magnesium alloys have a strong affinity for oxygen at high temperatures, especially in the molten state, making them highly susceptible to oxidation and combustion. This instantaneous reaction generates black oxides (MgO), severely contaminating the weld and even causing burning spatter. This is one reason why aluminum alloy studs are traditionally used in arc welding. To address this challenge, the magnesium alloy stud arc welding method provided in this application utilizes a continuous high-purity inert gas shielding throughout the entire process. This gas shielding is not limited to the moment of welding but is maintained before arc ignition, during welding, and after the molten pool solidifies. This effectively isolates the metal from air, ensuring that the high-temperature metal remains isolated from air throughout the entire melting and cooling process. This effectively prevents magnesium from reacting with oxygen at high temperatures, ensuring welding safety and joint purity, and improving the welding reliability of magnesium alloy products using magnesium alloy stud arc welding.

[0018] Furthermore, the magnesium alloy stud arc welding method provided in this application first cleans the surface of the weld point of the magnesium alloy product to be welded before proceeding with subsequent steps. This first cleans away the loose oxide film on the surface of the weld point of the magnesium alloy product, preventing it from hindering the fusion process and preventing it from absorbing moisture from the air, thereby effectively preventing the formation of weld porosity. At the same time, it also cleans away grease, stains and other impurities on the surface of the weld point of the magnesium alloy product, preventing them from affecting the stability of the arc welding, thereby further ensuring the reliability of the connection between the magnesium alloy product and the magnesium alloy stud. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1This is a flowchart of the magnesium alloy stud arc welding method provided in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the magnesium alloy stud provided in the embodiment of this application.

[0021] Figure label: 100-Magnesium Alloy Stud. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0027] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] like Figure 1 and Figure 2 As shown in the figure, this application provides a method for arc welding of magnesium alloy studs, including the following steps: Step S10: Prepare the magnesium alloy stud 100. AZ31 or AZ61 magnesium alloy is selected as the base material for the magnesium alloy stud 100 and it is then formed and manufactured. Figure 2 As shown, after the magnesium alloy stud 100 is manufactured, its surface is not subjected to additional treatment. The structural shape of the magnesium alloy stud 100 is consistent with that of the aluminum alloy stud, which facilitates its widespread standardized matching application.

[0030] This application embodiment uses a magnesium alloy stud 100, made from AZ31 or AZ61 base material with similar physical properties to the magnesium alloy product to be welded, for arc welding. Since they are from the same material source, their melting points, thermal conductivity, and coefficients of thermal expansion are very close, reducing problems such as heat input mismatch caused by dissimilar materials and lowering the tendency to crack. Under the same welding parameters, the two can basically achieve synchronous melting and solidification, forming a good metallurgical bond with low thermal stress and less susceptibility to hot cracks caused by inconsistent expansion and contraction. This solves the problems of incomplete welding and poor bonding caused by using aluminum alloy studs to weld magnesium alloy products in the prior art, achieving a reliable connection between the magnesium alloy product and the magnesium alloy stud 100, while meeting the actual use requirements of the magnesium alloy product.

[0031] Step S20: Clean the surface of the weld points on the magnesium alloy product to be welded.

[0032] The process cleans away the loose oxide film, grease, and stains on the surface of the weld joints of the magnesium alloy product, preventing the oxide film from hindering fusion and absorbing moisture from the air, thus effectively preventing the formation of weld porosity. It also cleans away grease, stains, and other impurities on the surface of the magnesium alloy to prevent them from affecting the stability of arc welding, thereby further ensuring the reliability of the connection between the magnesium alloy product and the magnesium alloy stud 100.

[0033] Step S30: High-purity inert gas is introduced for protection throughout the entire arc welding process. High-purity inert gas is introduced into the welding area between the magnesium alloy stud 100 and the magnesium alloy product to be welded for full protection.

[0034] Because magnesium alloys have a strong affinity for oxygen at high temperatures, especially in the molten state, they are very easy to oxidize and burn, instantly generating black oxides (MgO), which seriously contaminate the weld and may even cause burning spatter. This is one of the reasons why aluminum alloy studs are traditionally used in arc welding.

[0035] To address this challenge, the magnesium alloy stud arc welding method provided in this application utilizes a continuous high-purity inert gas supply throughout the entire welding process. This gas supply is not limited to the moment of welding but is maintained before arc ignition, during welding, and after the molten pool solidifies. This effectively isolates the metal from air, ensuring that the high-temperature metal remains isolated from air throughout the entire melting and cooling process. This effectively prevents magnesium from reacting with oxygen at high temperatures, ensuring a safe welding process and a clean joint, and improving the welding reliability of magnesium alloy products to be welded using magnesium alloy stud 100 arc welding.

[0036] Step S40: Set the arc welding process parameters, including the shielding gas delivery time parameter, the arc welding current parameter, and the arc welding time parameter. Specifically, the shielding gas delivery time parameter can be set to 900–1000 ms, such as 1000 ms; the arc welding current parameter can be set to 650–800 mA, such as 800 mA; and the arc welding time parameter can be set to 11–13 ms, such as 12 ms.

[0037] Because the welding window of magnesium alloys is very narrow, insufficient heat will lead to poor fusion, while excessive heat will cause severe oxidation, evaporation, spatter, or even burn-through. Prolonged welding time will expand the heat-affected zone, resulting in coarse grains and decreased performance.

[0038] This application embodiment sets an extremely short arc welding time (i.e., 11~13ms), minimizing the heat-affected zone. The welding process ends before heat can diffuse to the surrounding area, thus maximally suppressing grain coarsening and thermal deformation. It also minimizes the oxidation reaction time; with the aid of shielding gas, the time the high-temperature metal is exposed to residual oxygen is compressed to a very short period, minimizing the degree of oxidation. Furthermore, it suppresses the formation of weld porosity. Due to the extremely short duration of the molten pool, hydrogen does not have enough time to dissolve and accumulate, preventing the formation of weld porosity, thereby obtaining a dense weld and improving welding reliability.

[0039] Furthermore, the moderate arc welding current (650~800mA) compared to the extremely short arc welding time provides just enough energy to melt the stud end face and the local base material to form a molten pool, without causing excessive evaporation or spatter. In addition, ample shielding gas delivery time ensures a stable shielding gas environment is established before arc ignition and continues to provide protection after stud upsetting and complete molten pool solidification until the joint cools to a temperature below which oxidation is less likely, achieving full protection.

[0040] Step S50, welding operation: The magnesium alloy stud 100 prepared in step S10 and the magnesium alloy product to be welded cleaned in step S20 are precisely positioned, and the protective gas supply state of step S30 is maintained. Arc welding is carried out according to the arc welding process parameters set in step S40 to obtain the welded product.

[0041] Step S60: After welding is completed, torque test is performed on the welded joint between the obtained magnesium alloy stud 100 and the magnesium alloy product to be welded to check whether the joint is reliably connected.

[0042] In a further embodiment, in step S10, specifically, the surface of the weld joint of the magnesium alloy product to be welded is cleaned with a special cleaning agent. The special cleaning agent is one or more of an organic solvent cleaning agent, a weak alkaline composite cleaning agent, or a weak acid complexing cleaning agent. The organic solvent cleaning agent is one or more of anhydrous ethanol, isopropanol, and acetone, which can effectively dissolve and remove the loose oxide film, grease, stains, and other impurities on the surface of the magnesium alloy.

[0043] After cleaning, step S11 is included, in which anhydrous ethanol is used to wipe the solder joints of the magnesium alloy product to be welded to remove cleaning agent residue. Anhydrous ethanol can evaporate quickly, carrying away residual cleaning agent and water molecules, ensuring that the solder joint area is in an absolutely dry, residue-free, and hydrogen-free clean state, cutting off the main source of hydrogen from the source and effectively preventing the formation of porosity.

[0044] In one specific embodiment, in step S30, the high-purity inert gas can be high-purity argon or a mixture of high-purity argon and high-purity helium. Preferably, the purity of the high-purity argon is ≥99.99%, and the purity of the high-purity helium is ≥99.99%. The extremely low impurity content of high-purity argon and helium means extremely low oxygen and water content, ensuring the inert nature of the protective gas.

[0045] Preferably, if the high-purity inert gas is a mixture of high-purity argon and high-purity helium, the volume percentage of high-purity helium in the mixture is preferably 10% to 30%, with the remainder being high-purity argon. Since helium is lighter and has higher thermal conductivity than argon, adding 10% to 30% helium can increase the arc temperature and heat input, which is beneficial for welding thick magnesium alloy plates with high thermal conductivity or areas with rapid heat dissipation. It also improves the coverage of the shielding gas.

[0046] This application takes the magnesium alloy product to be welded using AZ91 magnesium alloy sheet as an example, and provides a specific embodiment to further describe the magnesium alloy stud arc welding method provided in this application. The specific operation steps are as follows: S10, Design and Manufacturing of Magnesium Alloy Stud 100: AZ31 magnesium alloy was selected as the base material for the magnesium alloy stud 100. After forming and manufacturing, the surface of the magnesium alloy stud 100 is not subjected to additional treatment. The structural shape of the magnesium alloy stud 100 is as follows: Figure 2 As shown, the magnesium alloy stud preferably adopts the M6 ​​specification size.

[0047] S20, AZ91 magnesium alloy sheet surface cleaning: Use acetone cleaner to clean the surface of the AZ91 magnesium alloy sheet. After cleaning, use anhydrous ethanol to wipe the weld points of the AZ91 magnesium alloy sheet to remove residual acetone and impurities on the surface, ensuring that the weld point area is clean and free of contaminants.

[0048] S30, Shielding gas introduction: Throughout the entire arc welding process, high-purity argon gas is used to protect the welding area between the AZ31 magnesium alloy stud and the AZ91 magnesium alloy plate, and the purity of the high-purity argon gas is ≥99.99%.

[0049] S40, Arc Welding Process Parameter Adaptation Settings: Set the welding shielding gas delivery parameters to 1000ms, the arc welding current to 800mA, and the arc welding time to 12ms.

[0050] S50, Welding operation: The AZ31 magnesium alloy stud prepared in step S10 and the AZ91 magnesium alloy plate cleaned in step S20 are precisely positioned, the high-purity argon gas supply in step S30 is maintained, and the two are subjected to arc welding according to the arc welding process parameters set in step S40, and finally a welded product with excellent welded joint performance is obtained.

[0051] S60. After welding, the torque of the welded joint between the M6 ​​specification AZ31 magnesium alloy stud and the AZ91 magnesium alloy plate was tested. The test showed that the torque of the welded joint was >3.5 N·m, indicating that the joint prepared by this welding method has excellent connection reliability and meets the preset usage requirements.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for arc welding of magnesium alloy studs, characterized in that, Includes the following steps: S10, prepare magnesium alloy studs, select AZ31 magnesium alloy or AZ61 magnesium alloy as the base material for preparing magnesium alloy studs and form them. S20, perform surface cleaning on the weld points of magnesium alloy products to be welded; S30, high-purity inert gas protection throughout the entire process, high-purity inert gas is introduced into the welding area between the magnesium alloy stud and the magnesium alloy product to be welded for full protection during the entire arc welding process. S40, set the arc welding process parameters, including shielding gas delivery time parameters, arc welding current parameters, and arc welding time parameters; S50, Welding operation: The magnesium alloy stud prepared in step S10 is precisely positioned with the magnesium alloy product to be welded after being cleaned in step S20, and the protective gas supply in step S30 is maintained. Arc welding is carried out according to the arc welding process parameters set in step S40 to obtain the welded product.

2. The magnesium alloy stud arc welding method according to claim 1, characterized in that, In step S40, the protective gas delivery time parameter is set to 900-1000ms, the arc welding current parameter is set to 650-800mA, and the arc welding time parameter is set to 11-13ms.

3. The magnesium alloy stud arc welding method according to claim 1, characterized in that, In step S20, the surface of the weld joint of the magnesium alloy product to be welded is cleaned with a special cleaning agent, which is one or more of organic solvent cleaning agents, weak alkaline composite cleaning agents, or weak acid complexing cleaning agents.

4. The magnesium alloy stud arc welding method according to claim 3, characterized in that, The organic solvent cleaning agent is one or more of anhydrous ethanol, isopropanol, and acetone.

5. The method for arc welding magnesium alloy studs according to claim 3 or 4, characterized in that, In step S20, after cleaning is completed, step S11 is also included, in which anhydrous ethanol is used to wipe the solder joints of the magnesium alloy product to be welded to remove cleaning agent residue.

6. The method for arc welding magnesium alloy studs according to claim 1, characterized in that, In step S30, the high-purity inert gas is high-purity argon, or a mixture of high-purity argon and high-purity helium.

7. The magnesium alloy stud arc welding method according to claim 6, characterized in that, The purity of the high-purity argon gas is ≥99.99%, and the purity of the high-purity helium gas is ≥99.99%.

8. The method for arc welding magnesium alloy studs according to claim 6 or 7, characterized in that, If the high-purity inert gas is a mixture of high-purity argon and high-purity helium, then the volume percentage of high-purity helium in the mixture is 10% to 30%, with the remainder being high-purity argon.

9. The method for arc welding magnesium alloy studs according to claim 1, characterized in that, After step S50, step S60 is also included: after welding is completed, torque test is performed on the welded joint between the obtained magnesium alloy stud and the magnesium alloy product to be welded to check whether the joint is reliably connected.

10. The method for arc welding magnesium alloy studs according to claim 1, characterized in that, The magnesium alloy product to be welded uses AZ91 magnesium alloy sheet.

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