Resistance spot welding control method and equipment, storage medium and product

Abstract

The invention discloses a resistance spot welding control method and device, a storage medium and a product, and relates to the technical field of resistance spot welding.The method comprises the steps that in the first stage of pre-energization, constant-current energization is conducted on a workpiece based on a first preset current value, and foreign matter removal on the surface of the workpiece is completed; in the second pre-electrifying stage, constant-current electrifying is conducted on the workpiece based on a second preset current value, and surface softening of the workpiece is completed; wherein the second preset current value is smaller than the first preset current value; under the condition that pre-electrification is completed, the workpiece is electrified according to a target strategy until welding is completed; wherein the target strategy is used for controlling workpiece formation and enlarging plastic rings and weld nuggets. According to the method, the pre-electrifying stages are split according to needs, and different electrifying modes are adopted, so that foreign matter removal and surface softening are independently carried out without interference, the pretreatment effect is improved, incomplete foreign matter removal or surface ablation is avoided, and a foundation is laid for better formation and expansion of a plastic ring and a weld nugget in the subsequent welding process.

Description

Technical Field

[0001] This application relates to the field of plate spot welding technology, and in particular to a spot welding control method, equipment, storage medium and product. Background Technology

[0002] In related technologies, resistance spot welding typically employs direct welding or two-stage energized welding. Two-stage energized welding generally includes two stages: pre-energization and secondary energization.

[0003] In the pre-energization process, related technologies often use a constant current to energize the surface. However, this can lead to inconsistent levels of surface foreign matter removal and may also result in liquid metal splashing, increasing the probability of defects in the final product.

[0004] Therefore, improving welding precision and reducing product defect rates are urgent problems that need to be solved. Summary of the Invention

[0005] The main objective of this application is to provide a spot welding control method, equipment, storage medium, and product, which aims to solve the technical problem of how to avoid the explosion of the weld nugget during resistance spot welding while taking into account the weld nugget diameter.

[0006] To achieve the above objectives, this application proposes a spot welding control method, which includes: In the first stage of pre-energization, the workpiece is energized by constant current based on the first preset current value to remove foreign objects from the surface of the workpiece. In the second pre-energization stage, the workpiece is subjected to constant current based on the second preset current value to soften the surface of the workpiece; wherein, the second preset current value is less than the first preset current value; With pre-energization completed, a target strategy is used to energize the workpiece until welding is completed; the target strategy is used to control the formation and expansion of the plastic ring and weld nugget on the workpiece.

[0007] In some embodiments, the first preset current value is greater than or equal to 8 kA and less than or equal to 14 kA.

[0008] In some embodiments, the difference between the second preset current value and the first preset current value is less than or equal to 5 kiloamperes.

[0009] In some embodiments, the resistance spot welding control method further includes: The difference between the second preset current value and the first preset current value is determined based on the workpiece's model and / or thickness.

[0010] In some embodiments, after pre-energization is completed, a target strategy is used to energize the workpiece until welding is completed, including: When pre-energization is completed, a uniformly varying and / or constant current is applied to the workpiece during a first preset time period to expand the plastic ring and form a weld nugget; wherein, at the end of the first preset time period, the real-time value of the current is equal to the first current value. During a second preset time period, a uniformly varying and / or constant current is applied to the workpiece to expand the weld nugget; wherein, at the end of the second preset time period, the real-time value of the current is equal to the second current value, and the second current value is greater than the first current value. A constant current is applied to the workpiece during the third preset time period to further expand the weld nugget until welding is completed; wherein, the magnitude of the constant current is the third current value, and the third current value is greater than or equal to the second current value.

[0011] In some embodiments, after the surface of the workpiece has been softened, the workpiece is energized with a continuously increasing current until welding is completed. The resistance spot welding control method further includes: Based on the workpiece model and / or thickness, a target strategy is determined, wherein the target strategy includes the duration of a first preset time period, a second preset time period, and a third preset time period, as well as a first current value, a second current value, and a third current value.

[0012] In some embodiments, a constant current is applied to the workpiece to further expand the weld nugget until a third preset time is reached. After welding is completed, the resistance spot welding control method further includes: After welding is completed, assess whether the weld nugget diameter of the welded workpiece meets the preset requirements; If the weld nugget diameter of the workpiece does not meet the preset requirements, return to the step of applying a uniformly varying and / or constant current to the workpiece to expand the plastic ring until the weld nugget diameter of the workpiece meets the preset requirements.

[0013] In addition, to achieve the above objectives, this application also proposes a spot welding control device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the spot welding control method as described above.

[0014] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the spot welding control method described above.

[0015] In addition, to achieve the above objectives, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the spot welding control method described above.

[0016] One or more technical solutions proposed in this application have at least the following technical effects: The pre-energizing stage is divided into two phases: the first phase uses a first preset current value to continuously energize the workpiece to remove foreign matter; the second phase uses a second preset current value, lower than the first preset value, to continuously energize the surface to soften it. By splitting the pre-energizing stage as needed and using different energizing methods, foreign matter removal and surface softening can be carried out independently without interference, thereby improving the pretreatment effect, avoiding incomplete foreign matter removal or surface ablation, and laying the foundation for better formation and expansion of the plastic ring and weld nugget during subsequent welding. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic flowchart of a resistance spot welding control method provided in an embodiment of this application is shown; Figure 2 This illustration shows a schematic diagram of a mapping relationship presented in tabular form according to an exemplary embodiment of this application; Figure 3 A schematic diagram of the structure of a resistance spot welding control device provided in an embodiment of this application is shown.

[0020] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0022] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0023] The main solution of this application embodiment is as follows: In the first pre-energization stage, the workpiece is subjected to constant current based on a first preset current value to remove foreign matter from the workpiece surface; in the second pre-energization stage, the workpiece is subjected to constant current based on a second preset current value to soften the workpiece surface; wherein, the second preset current value is less than the first preset current value; when the pre-energization is completed, the workpiece is energized using a target strategy until welding is completed; wherein, the target strategy is used to control the formation and expansion of the plastic ring and weld nugget in the workpiece.

[0024] In related technologies, resistance spot welding typically employs direct welding or two-stage energized welding. Two-stage energized welding generally includes two stages: pre-energization and secondary energization.

[0025] In the pre-energization process, related technologies often use a constant current to energize the surface. However, this can lead to inconsistent levels of surface foreign matter removal and may also result in liquid metal splashing, increasing the probability of defects in the final product.

[0026] In summary, improving welding precision and reducing product defect rates are urgent issues that need to be addressed.

[0027] Based on this, this application provides a solution that breaks down the pre-energization process of resistance spot welding into multiple stages, with different current values ​​used for different stages. This results in better removal of foreign matter and more effective surface softening that better meets actual needs, improving the precision of resistance spot welding, laying the foundation for subsequent welding, and reducing the defect rate of the welded product.

[0028] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or a spot welding control device capable of performing the above functions. The following description uses a spot welding control device as an example to illustrate this embodiment and the subsequent embodiments.

[0029] Reference Figure 1 , Figure 1 A schematic flowchart of a resistance spot welding control method according to an embodiment of this application is shown. The resistance spot welding control method can be applied to resistance spot welding control equipment and includes the following steps S110 to S130: Step S110: In the first pre-energization stage, the workpiece is energized with constant current based on the first preset current value to remove foreign matter from the workpiece surface.

[0030] Resistance spot welding is a welding method that uses resistance heat to connect metal workpieces at localized points. It involves applying pressure to the workpiece through electrodes and passing a certain current through it. At the contact point, high heat is generated due to resistance, causing the metal to melt and form a connection, thus creating a welded part.

[0031] Resistance spot welding typically includes five stages: startup, pre-pressure, pre-energization, welding, and output. These five stages will be described in detail below.

[0032] ①Startup Phase In this embodiment, the resistance spot welding control equipment may include electrodes. The startup phase involves connecting the electrodes to the designated welding position on the workpiece and setting the relevant welding parameters. The welding parameters can be obtained by looking up relevant mapping relationships. It is understood that welding typically involves welding multiple workpieces (e.g., plates) together. Different workpiece combinations have different resistance spot welding characteristics, resulting in different welding parameters to be used during the resistance spot welding process. In this embodiment, for workpieces of various types and / or sizes, relevant tests can be conducted in advance to obtain the welding parameters for the following stages, forming a mapping relationship, which is then presented in the form of tables, etc.

[0033] In some implementations, for the same workpiece model and / or size, there can be multiple sets of welding parameters. Each set of welding parameters can complete the corresponding resistance spot welding, but there are certain differences between them. For example, the total welding time corresponding to multiple sets of welding parameters can be different, and the workpiece gaps applicable to multiple sets of welding parameters can be different.

[0034] Based on this, users can select a suitable set of parameters from multiple options to execute, according to the required duration of the entire welding process. For example, assume workpiece 1 is model A with size a; workpiece 2 is model B with size b; and workpiece 3 is model C with size c. This resistance spot welding requires welding A, B, and C together. By looking up A, B, C, a, b, and c in a table, two sets of welding parameters are found to meet this condition. The first set has a total welding time of X, suitable for welding workpiece gaps less than 2 mm; the second set has a total welding time of Y, suitable for welding workpiece gaps less than 1.5 mm. In one example, the worker finds that the planned total time for this resistance spot welding is Z, which is greater than X and less than Y. Therefore, to ensure timely completion of the resistance spot welding, the worker can choose to use the first set of welding parameters. In another example, the worker finds that the gap between the workpieces is 1.7 mm, and thus chooses to use the first set of welding parameters.

[0035] ②Pre-compression stage Understandably, welding typically involves joining multiple workpieces (such as plates) together, and gaps may exist between these workpieces. Resistance spot welding, however, aims to minimize these gaps and maximize the contact area at the welding point to prevent localized arcing or burn-through caused by these gaps.

[0036] Different workpieces have different surface conditions, therefore the applied pressure varies depending on the workpiece. As mentioned earlier, resistance spot welding tests can be performed on workpieces of different models and sizes (e.g., sheet metal thickness) in advance, and the test results can be statistically analyzed. Based on the statistical results, the pre-pressure value and pre-pressure time for workpieces of different models and sizes can be determined and added to the mapping relationship mentioned above.

[0037] In practical applications, when resistance spot welding is required, the pre-compression pressure and time can be directly determined by matching the model and size of the workpiece to be welded. Specifically, for every 1 mm increase in plate thickness, the pre-compression pressure can be increased by approximately 500 N.

[0038] ③ Pre-energization stage After the pre-pressure is completed, there may be some surface foreign matter on the workpiece surface, so it is necessary to remove the surface foreign matter through the pre-energization stage.

[0039] Specifically, surface foreign matter refers to oxide films or oil layers present on the surface of metal workpieces, such as the aluminum oxide film on aluminum alloys and the zinc oxide film on galvanized steel. These surface foreign matter have high resistivity and instability, which can easily cause drastic fluctuations in current density during subsequent welding processes, thereby causing spatter or uneven weld nuggets, seriously affecting the quality of the welded product.

[0040] In this embodiment, the pre-energizing stage may include a first stage and a second stage. In the first pre-energizing stage, a first preset current can be used to continuously energize the workpiece to remove foreign matter from the workpiece surface.

[0041] The first preset current can be set to less than or equal to 14 kA and greater than or equal to 8 kA. It is understood that the first preset current needs to penetrate the surface foreign matter on the workpiece to achieve removal. However, due to differences in the model and size of the workpiece, the surface foreign matter that needs to be penetrated will vary, thus affecting the first preset current. Therefore, as mentioned earlier, pre-testing is performed on workpieces of different types and sizes to determine the first preset current corresponding to each of the aforementioned groups, and this is added to the aforementioned mapping relationship. For example, the first preset current in the first group of welding parameters is 12 kA, while the first preset current in the second group of welding parameters is 11 kA.

[0042] It is understandable that, since the initial preset current for breaking down surface foreign objects is usually quite large, if the duration is too long, the workpiece may melt prematurely before reaching the welding stage, potentially leading to spatter or uneven weld nugget formation. Therefore, in this embodiment, the energizing time of the initial preset current for each group can be set to approximately one cycle, and not exceeding two cycles (abbreviated as cyc, where one cyc corresponds to one cycle of a 50Hz power grid, i.e., one cycle is 1 / 50th of a second), thereby preventing the workpiece from melting. In some feasible implementations, the energizing time of the initial preset current can also be set to other values, which can be adjusted adaptively by the operator as needed; this embodiment does not impose such limitations.

[0043] It is understandable that only when the electric field strength instantaneously exceeds the critical value can the surface foreign matter be broken down. Therefore, to ensure the removal effect of foreign matter, this embodiment directly uses a constant current to ensure that the surface foreign matter can be stably broken down during the energizing process.

[0044] Step S120: In the second pre-energization stage, the workpiece is subjected to constant current based on the second preset current value to complete the surface softening of the workpiece; wherein, the second preset current value is less than the first preset current value.

[0045] In the second stage of pre-energization, foreign objects on the surface have been removed and pre-pressed, and the surface of the workpiece is relatively close, but there are still some gaps. Therefore, in this embodiment, the surface of the workpiece is designed to be softened in the second stage.

[0046] Specifically, the workpiece can be energized with a second preset current. This second preset current can be lower than the first preset current because high-resistivity foreign matter on the surface has been removed, and maintaining a higher first preset current might cause further breakdown of the workpiece. In this embodiment, the difference between the second and first preset currents can be between 3 and 6 amperes, preferably controlled at around 5 kA. If it is lower than 5 kA, the weld nugget may form before the plastic ring, affecting the welding effect.

[0047] As mentioned earlier, the second preset current can be different for different groups. After the selected second preset current is applied to the workpiece, the workpiece surface softens due to heat, resulting in a tighter fit between the electrode and the workpiece surface. This establishes a stable, low-impedance electrical contact path, preventing spatter caused by localized overheating during the main welding stage.

[0048] Understandably, the second preset current is also energized using a constant current method and maintained for a certain duration, with the energizing duration controlled between one and three cycles, so that the softening of the workpiece surface can be more uniform.

[0049] For materials with high electrical conductivity and fast thermal conductivity, such as aluminum alloys, the current can be appropriately increased, for example, to 7-10KA, thereby improving heat input efficiency and accelerating softening to eliminate gaps.

[0050] This concludes the pre-energizing stage. During the pre-energizing process, surface foreign matter between the electrodes and the workpiece, and between the workpieces themselves, is first removed. Then, a slightly lower current is used to soften the workpiece surface, resulting in a tighter fit between the workpieces. Compared to related technologies that use a constant current throughout the pre-energizing stage, this embodiment divides the pre-energizing stage into a first stage and a second stage according to the desired function. This clear division of labor prevents both insufficient current leading to poor foreign matter removal and excessive current causing splashing, thus achieving a better pre-treatment effect.

[0051] Step S130: With pre-energization completed, the workpiece is energized using the target strategy until welding is completed.

[0052] After the pre-energization stage is completed, the welding stage begins. During the welding stage, different workpiece types and / or thicknesses require different target strategies. These target strategies control the formation and expansion of the plastic ring and weld nugget. Specifically, based on the multiple stages defined below, the target strategies may include the durations of the first, second, and third preset time periods, as well as the first, second, and third current values. The target strategy for each stage can be obtained through the aforementioned mapping relationship, which will not be elaborated further here.

[0053] Understandably, workers can determine the target strategy to be adopted in the aforementioned stage ① by matching the workpiece model and / or size in the mapping relationship.

[0054] ④ Welding stage In this embodiment, the welding stage is further subdivided into multiple sub-stages 1.1 to 1.3 according to the functions to be implemented.

[0055] 1.1: Plastic ring expansion stage.

[0056] The plastic ring refers to the solid metal region that has undergone high-temperature plastic deformation before it melts, after the formal entry into the welding stage. The plastic ring surrounds the molten metal, and the molten metal in it further forms a weld nugget during the welding process.

[0057] In this embodiment, after pre-energization is completed, a uniformly varying and / or constant current is applied to the workpiece during a first preset time period to expand the plastic ring and form a weld nugget; wherein, at the end of the first preset time period, the real-time value of the current is equal to the first current value.

[0058] Understandably, after the metal begins to melt and form a plastic ring, a weld nugget can form within the plastic ring. A good welding process requires the plastic ring to surround the weld nugget. By controlling the current during the first preset time period, the amount of input energy is controlled, causing the diameter of the plastic ring to expand uniformly. At the same time, the weld nugget is initially formed inside the plastic ring, laying the foundation for the growth of the weld nugget in subsequent stages.

[0059] In this embodiment, uniform change can include uniform rise and uniform fall. Constant, uniform rise, and uniform fall can be used individually or in combination, depending on the type and size of the workpiece.

[0060] As an example, by consulting a table, the current can be increased uniformly from the value at the end of stage ③ (e.g., 6.0 kA) to a first current value (e.g., 6.8 kA) over a first preset time period (e.g., 5 cycles). As another example, by consulting a table, the current can also be switched directly from the value at the end of stage ③ (e.g., 7.0 kA) to the first current value (e.g., 6.4 kA) and kept constant until the first preset time period (e.g., 1 cycle) is reached. As yet another example, after uniformly changing to a specified first current value, the first current value can be maintained for a specified duration.

[0061] Understandably, suddenly applying a large, constant current can easily lead to a sharp increase in local temperature, causing the metal to melt rapidly and spatter. To avoid this, as a preferred implementation, a method of uniformly varying the current can be used during the expansion stage of the plastic ring, allowing the local temperature to rise slowly, the plastic ring to expand steadily, and the molten metal to remain stably within the plastic ring to initially form a weld nugget, thereby avoiding spatter.

[0062] In addition, for plates with high hardness values ​​such as high-strength steel, which are difficult to plastically deform, the duration of the first preset time period can be extended in this embodiment. For example, the first preset time period can be extended to 11 cycles to ensure that the plastic ring and the formation / expansion rhythm of the weld nugget match, and to avoid the weld nugget growth being limited due to excessive material hardness.

[0063] 1.2: Weld nugget growth stage.

[0064] In this embodiment, a uniformly varying and / or constant current can be applied to the workpiece during a second preset time period to expand the weld nugget.

[0065] Understandably, as the temperature rises, the weld nugget and the plastic ring expand synchronously with the melting of more metal. Since the molten metal may overflow (or spill out) from the plastic ring due to thermal expansion, causing spatter, in a preferred embodiment, after determining the duration of the second preset time period and the corresponding second current value by looking up a table, the current is increased from the first current value to the second current value within the duration of the second preset time period using a uniform variation method. This ensures that no spatter caused by a surge in heat is generated. Simultaneously, using a uniform variation method can also limit the expansion rate of the weld nugget, preventing it from expanding too quickly and exceeding the range of the plastic ring. This ensures that the molten metal remains within the plastic ring, and that both the plastic ring and the weld nugget expand slowly and synchronously, thereby ensuring that the molten metal is in a controllable state. Specifically, to ensure that the plastic ring and the weld nugget are in an expanding state, the second current value can be greater than the first current value.

[0066] In some feasible implementations, a method of first uniformly changing the current and then maintaining a constant current can also be adopted. It is understood that, similar to the relevant section in stage 1.1 above, the selection of the current change pattern is related to the model and / or size of the workpiece being resistively welded, and is determined by the operator based on results obtained from a table. In this embodiment, the overall goal is to ensure that the weld nugget and the plastic ring expand synchronously during the weld nugget growth stage, and that the weld nugget does not exceed the range of the plastic ring.

[0067] 1.3: Weld nugget expansion stage.

[0068] In this embodiment, a constant current can be applied to the workpiece during a third preset time period to further expand the weld nugget until welding is completed.

[0069] In process 1.1-1.2, a uniformly varying current flow is used, which may result in areas at the edge of the plastic ring where weld nuggets cannot form. Specifically, because the current increases slowly over a long period, some of the heat generated by the current flow is gradually conducted from the edge of the plastic ring to the entire conductor (i.e., the workpiece). This causes a semi-molten area to appear at the edge of the plastic ring due to insufficient temperature. This semi-molten area cannot form a weld nugget, which effectively limits the expansion of the weld nugget.

[0070] To further expand the diameter of the weld nugget, this embodiment sets the duration of constant current energization during the weld nugget expansion stage, specifically the third preset time period. Specifically, since steps 1.1-1.2 have already stably expanded the edge of the plastic ring, forming a relatively standardized weld nugget, a constant current can be used in step 1.3 to increase energy density to a certain extent, accelerate the melting of the semi-molten region, reduce the semi-molten region at the edge of the plastic ring, and provide sufficient heat for weld nugget growth, thus further expanding the weld nugget diameter. It is understood that to ensure further expansion of the weld nugget diameter, the third current value should be greater than or equal to the second current value.

[0071] It should be noted that any of the above stages (including ①-④ and 1.1-1.3) can have multiple sub-stages. Within each sub-stage, the current can be controlled using either uniform variation or constant current. For example, in the weld nugget growth stage (1.2), there can be five sub-stages: the first sub-stage uses uniform variation, the second sub-stage uses constant current, the third sub-stage continues with uniform variation, the fourth sub-stage remains constant, and the fifth sub-stage further uses uniform variation. It is understood that workers can divide each stage into different numbers and durations of sub-stages according to actual needs; this embodiment does not impose such limitations.

[0072] It should be noted that for plates with a thickness of 3 mm or more, a transition stage can be added after stage ④, in which a constant current (7-7.5 kA) is applied to the plate within 1-3 cycles to avoid uneven weld nugget growth due to thickness.

[0073] ⑤ Output stage.

[0074] Having completed stages ①-④, the welding of the workpiece in this round is now complete. In this embodiment, after welding is completed, it can be evaluated whether the weld nugget diameter of the welded workpiece meets the preset requirements.

[0075] The preset requirements could include whether the weld nugget diameter meets a predetermined limit, which can be set in advance by the staff. Understandably, if the preset requirements are not met, the workpiece needs further processing until they are satisfied.

[0076] Specifically, if the diameter of the weld nugget on the workpiece does not meet the preset requirements, return to step ④ above to further enlarge the plastic ring and weld nugget until the weld nugget can meet the preset requirements.

[0077] In some implementations, a post-weld heat treatment stage may be included between the weld nugget expansion stage ④ and the output stage ⑤. The post-weld heat treatment stage typically includes six sub-stages, each employing different currents and energizing methods. The purpose of the post-weld heat treatment stage is to improve the performance of the weld joint, and it usually includes heat treatment processes such as tempering and slow cooling.

[0078] During tempering, a lower current is required, and the weld joint's toughness and fatigue resistance are improved through prolonged secondary heating. During slow cooling, a continuous current is applied to maintain the weld nugget's temperature and extend the cooling time, thereby reducing porosity, improving the uniformity of the weld nugget's solidification structure, and increasing the welding strength.

[0079] For plates with high hardness, such as high-strength steel, a low current can be continuously applied for an extended period during post-weld heat treatment to reduce stress concentration. For materials with high electrical and thermal conductivity, such as aluminum alloys, a higher current and shorter application time can be used to match their rapid heat dissipation characteristics and ensure that the weld nugget diameter expands as expected.

[0080] In some implementations, for plates with a thickness of 0.5 mm or less, the six stages can be combined into four or five stages while keeping the total duration of the post-weld heat treatment stage unchanged. This simplifies the control logic by reducing the number of segments and avoids fluctuations in heat input.

[0081] In some implementations, the current can be controlled in a step-by-step increasing manner during each sub-stage of the post-weld heat treatment process. Specifically, the current can increase by 0.5 kA every three sub-stages; for example, the current is 9 kA for the first three sub-stages, and then increases to 9.5 kA for the fourth to sixth sub-stages. This small current of 0.5 kA compensates for heat loss during the welding process, promoting uniform weld nugget growth from the center to the edge.

[0082] For welding applications requiring high toughness (such as automotive chassis components), a "constant + pulsed" current control approach can be introduced during post-weld heat treatment. Specifically, a 0.3kA pulsed current lasting 0.5 cycles can be superimposed every two cycles. By intermittently superimposing pulsed currents, the grains within the molten pool can be refined using pulsed disturbances, reducing porosity defects and thus improving the fatigue strength of the welded joint.

[0083] This embodiment provides a resistance spot welding control method that divides the pre-energizing stage into two stages: the first stage uses a first preset current value to continuously energize the workpiece to remove foreign matter; the second stage uses a second preset current value lower than the first preset value to continuously energize the workpiece to achieve surface softening. By dividing the pre-energizing stage as needed and using different energizing methods, foreign matter removal and surface softening can be carried out independently without interference, thereby improving the pretreatment effect, avoiding incomplete foreign matter removal or surface ablation, and laying the foundation for better formation and expansion of the plastic ring and weld nugget during subsequent welding.

[0084] To aid in understanding the implementation process of the resistance spot welding control method obtained by combining this embodiment with the above embodiments, an exemplary embodiment is provided here.

[0085] Assuming that a mapping relationship has been pre-established through preliminary experiments and statistics, presented in tabular form, multiple parameter combinations corresponding to each workpiece type and size have been added to the table.

[0086] In practical applications, the staff first determines the workpiece to be resisted spot welded according to the work order. The workpiece includes three plates: plate 1 (model A01, thickness 0.65), plate 2 (model A02, thickness 1.60), and plate 3 (model A03, thickness 1.30).

[0087] Based on the type (model) and size (thickness) of these three plates, a table shows three possible parameter combinations. The staff, considering the overall production process, selected the first parameter combination to perform resistance spot welding.

[0088] During the startup phase, the operator starts the resistance spot welding control equipment. The equipment's display interface shows multiple stages, each corresponding to an input box. The operator fills in the parameters from the table into the corresponding input boxes, and then starts the resistance spot welding control equipment to begin the welding process.

[0089] During the pre-pressing stage, the resistance spot welding control equipment moves the electrode to the designated position on the workpiece surface and then applies pressure to the electrode, using a force of 3430N to apply pressure to the electrode for 10 cycles.

[0090] During the pre-energizing and welding stages, the current changes can be as follows: Figure 2 As shown.

[0091] In ①, the energizing time is 1 cycle, and a constant current of 12KA is used to eliminate surface foreign matter. In ②, the energizing time is 2 cycles, and a constant current of 6KA is used to soften the surface of the board. In ③, the energizing time is 5 cycles, and the current is increased from 6KA to 6.8KA in a uniform rising manner to initially control the heat and make initial preparations for the formation of the plastic ring; In step ④, the energizing time is 4 cycles, and the current is increased from 6.8KA to 7.2KA in a uniform rising manner; after step ④, the current is maintained at 7.2KA for 1 cycle, so that the plastic ring and weld nugget are initially formed. In step ⑤, the energizing time is 3 cycles, and the current is increased from 7.2KA to 7.6KA in a uniform rising manner; after step ⑤, the current is maintained at 7.6KA for 1 cycle to refine heat control and enhance the molding effect. In step ⑥, the energizing time is 2 cycles, and the current is increased from 7.6KA to 7.8KA using a uniform rising method; In step ⑦, the energizing time is 2 cycles, and the current is increased from 7.8KA to 8.2KA using a uniform rising method; through steps ⑥ and ⑦, the current is smoothly transitioned to step ⑧. In step ⑧, the energizing time is 2 cycles, and the current is kept at 8.2KA using a constant current method to increase the weld nugget diameter.

[0092] Wherein, ① corresponds to the first pre-energization stage in the aforementioned embodiments, ② corresponds to the second pre-energization stage in the aforementioned embodiments, ③-④ correspond to the plastic ring expansion stage in the aforementioned embodiments, ⑤-⑦ correspond to the weld nugget growth stage in the aforementioned embodiments, and ⑧ corresponds to the weld nugget expansion stage in the aforementioned embodiments.

[0093] After the welding stage is completed, the output stage is entered for inspection to determine whether the current weld nugget diameter meets the preset requirements. If the preset requirements are met, the process returns to the aforementioned welding stage (i.e., returns to the previous step). Figure 2 (③) until the weld nugget diameter meets the preset requirements.

[0094] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the resistance spot welding control method of this application. Any simple modifications based on this technical concept are within the protection scope of this application.

[0095] This application provides a resistance spot welding control device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the resistance spot welding control method in the first embodiment described above.

[0096] The following is for reference. Figure 3The diagram illustrates a structural schematic suitable for implementing the resistance spot welding control device of the embodiments of this application. The resistance spot welding control device in the embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), vehicle terminals (e.g., vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 3 The resistance spot welding control device shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0097] like Figure 3 As shown, the resistance spot welding control device 100 may include a processing unit 110 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 120 or a program loaded from a storage device 130 into a random access memory (RAM) 140. The RAM 140 also stores various programs and data required for the operation of the resistance spot welding control device. The processing unit 110, ROM 120, and RAM 140 are interconnected via a bus 150. An input / output (I / O) interface 160 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 160: input devices 170 including, for example, a touchscreen, touchpad, keyboard, mouse, image sensor, microphone, accelerometer, gyroscope, etc.; output devices 180 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; storage devices 130 including, for example, magnetic tape, hard disk, etc.; and communication devices 190. Communication device 190 allows the resistance spot welding control equipment to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows resistance spot welding control equipment with various systems, it should be understood that implementation or possession of all the systems shown is not required. More or fewer systems may be implemented alternatively.

[0098] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 130, or installed from ROM 120. When the computer program is executed by processing device 110, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0099] The resistance spot welding control equipment provided in this application, employing the resistance spot welding control method in the above embodiments, can solve the technical problem of how to improve welding precision and reduce product defect rate. Compared with the prior art, the beneficial effects of the resistance spot welding control equipment provided in this application are the same as those of the resistance spot welding control method provided in the above embodiments, and other technical features of this resistance spot welding control equipment are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0100] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0101] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0102] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the resistance spot welding control method in the above embodiments.

[0103] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0104] The aforementioned computer-readable storage medium may be included in the resistance spot welding control equipment; or it may exist independently and not assembled into the resistance spot welding control equipment.

[0105] The aforementioned computer-readable storage medium carries one or more programs that, when executed by the resistance spot welding control device, enable the resistance spot welding control device to write computer program code for performing the operations of this application in one or more programming languages ​​or a combination thereof. These programming languages ​​include object-oriented programming languages—such as Java, Smalltalk, and C++—and conventional procedural programming languages—such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0106] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0107] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0108] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described resistance spot welding control method, which can solve the technical problem of how to improve welding precision and reduce product defect rate. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as the beneficial effects of the resistance spot welding control method provided in the above embodiments, and will not be repeated here.

[0109] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the resistance spot welding control method described above.

[0110] The computer program product provided in this application can solve the technical problem of how to improve welding precision and reduce product defect rate. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the resistance spot welding control method provided in the above embodiments, and will not be repeated here.

[0111] The above description is only a part of the embodiments of this application and does not limit the scope of protection of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for controlling resistance spot welding, characterized in that, The resistance spot welding control method includes: In the first pre-energization stage, the workpiece is energized with constant current based on the first preset current value to remove foreign matter from the surface of the workpiece. In the second pre-energization stage, the workpiece is subjected to constant current based on a second preset current value to soften the surface of the workpiece; wherein, the second preset current value is less than the first preset current value; With pre-energization completed, the workpiece is energized using a target strategy until welding is completed; wherein, the target strategy is used to control the formation and expansion of the plastic ring and weld nugget on the workpiece.

2. The resistance spot welding control method as described in claim 1, characterized in that, The first preset current value is greater than or equal to 8 kA and less than or equal to 14 kA.

3. The resistance spot welding control method as described in claim 2, characterized in that, The difference between the second preset current value and the first preset current value is less than or equal to 5 kiloamperes.

4. The resistance spot welding control method according to any one of claims 1-3, characterized in that, The resistance spot welding control method further includes: The difference between the second preset current value and the first preset current value is determined based on the model and / or thickness of the workpiece.

5. The resistance spot welding control method as described in claim 4, characterized in that, The step of applying a target strategy to energize the workpiece after pre-energization is completed, until welding is completed, includes: When pre-energization is completed, a uniformly varying and / or constant current is applied to the workpiece during a first preset time period to expand the plastic ring and form the weld nugget; wherein, at the end of the first preset time period, the real-time value of the current is equal to the first current value; During a second preset time period, a uniformly varying and / or constant current is applied to the workpiece to expand the weld nugget; wherein, at the end of the second preset time period, the real-time value of the current is equal to the second current value, and the second current value is greater than the first current value. A constant current is applied to the workpiece during a third preset time period to further expand the weld nugget until the welding is completed; wherein, the magnitude of the constant current is a third current value, and the third current value is greater than or equal to the second current value.

6. The resistance spot welding control method as described in claim 5, characterized in that, The resistance spot welding control method further includes, after the surface of the workpiece has been softened, applying a continuously increasing current to the workpiece until welding is completed: The target strategy is determined based on the model and / or thickness of the workpiece, wherein the target strategy includes the duration of a first preset time period, a second preset time period, and a third preset time period, as well as a first current value, a second current value, and a third current value.

7. The resistance spot welding control method as described in claim 6, characterized in that, After the constant current is applied to the workpiece to further expand the weld nugget until a third preset time is reached and the welding is completed, the resistance spot welding control method further includes: After the welding is completed, evaluate whether the weld nugget diameter of the welded workpiece meets the preset requirements; If the weld nugget diameter of the workpiece does not meet the preset requirement, return to the step of passing a uniformly varying and / or constant current through the workpiece to expand the plastic ring until the weld nugget diameter of the workpiece meets the preset requirement.

8. A resistance spot welding control device, characterized in that, The resistance spot welding control device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the resistance spot welding control method as described in any one of claims 1 to 7.

9. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the resistance spot welding control method as described in any one of claims 1 to 7.

10. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the steps of the resistance spot welding control method as described in any one of claims 1 to 7.

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