Welding method for stainless steel pipeline used in air conditioner

Abstract

The present invention relates to the field of welding technology, and particularly to a welding method for stainless steel pipelines used in air conditioners, including: pretreating the copper pipe and the stainless steel pipe, flaring the two ends of the stainless steel port, and inserting the ports of the copper pipe into the two ends of the stainless steel pipe respectively; sleeving a welding ring at the welding joint and heating to form a brazed joint. Among them, the welding infrared image is collected in real time to determine the temperature change area, and then the temperature difference degree and change synchronization are determined to predict the flow rate of the welding ring solder; the welding area image is collected in real time to determine the flow state of the welding ring, and the heating power or heating time is adjusted according to the flow rate, flow state, thermal conductivity of the welding ring and pipe material parameters, and the position of the welding ring during the next welding is adjusted according to the flow state; the present invention can optimize the welding parameters in time according to the actual welding situation, make the welding ring flow evenly to fill the weld seam, form a smooth and dense brazed joint, and improve the welding quality.

Description

Technical Field

[0001] The present invention relates to the field of welding technology, and particularly to a welding method for stainless steel pipelines used in air conditioners. Background Art

[0002] In existing air conditioner pipelines, the forms of all copper or copper + aluminum pipes (with a thermoplastic pipe wrapped outside) are often used. However, the price of copper is high, which will increase the production cost of air conditioners. Moreover, due to its fast heat dissipation characteristic, it will affect the gas-liquid separation effect, resulting in the compressor sucking in liquid refrigerant, reducing the compressor efficiency, and ultimately causing a low coefficient of performance (COP) of the air conditioner, affecting the cooling and heating efficiency of the air conditioner and increasing energy consumption. The copper-aluminum connecting pipe is not environmentally friendly, and due to the different densities of copper and aluminum, a primary battery will be formed in an electrolyte environment, posing a risk of galvanic corrosion, which will further increase air conditioner failures.

[0003] Chinese Patent Publication No.: CN107127467A discloses a welding method for shock-absorbing pipes used in air conditioners, an air conditioner pipeline system, and an air conditioner. The welding method for the shock-absorbing pipe used in the air conditioner includes: providing a shock-absorbing pipe; the shock-absorbing pipe includes a pipe body and pipe joints welded and fixed at both ends of the pipe body, and the welding temperature of the pipe joint and the pipe body is T1; welding and fixing one end of the pipe joint away from the pipe body to the air conditioner pipeline; the welding temperature of the pipe joint and the air conditioner pipeline is T2, and T2 and T1 satisfy the relationship: T2 < T1. It can be seen that although the above technical solution can achieve the welding of the pipe joint and the pipe body as well as the pipe joint and the air conditioner pipeline, it does not consider the adaptability problem of welding different materials. For example, the differences in thermal conductivity and melting point of different materials will affect heat transfer and welding effects. Summary of the Invention

[0004] Therefore, the present invention provides a welding method for stainless steel pipelines used in air conditioners to overcome the problems in the prior art that during the welding of air conditioner pipelines, the welding material dissipates heat too fast, the manufacturing cost is high, which affects the performance of the air conditioner, and at the same time, the material characteristics of the welding material are not considered during welding, which affects the welding quality.

[0005] To achieve the above object, the present invention provides a welding method for stainless steel pipelines used in air conditioners, including:

[0006] Step S1, preprocessing the ports of the copper pipe to be welded and the ports of the stainless steel pipe;

[0007] Step S2, flaring the two ends of the stainless steel port, and inserting the ports of the copper pipe into the two ends of the flared stainless steel pipe respectively to form a welding joint;

[0008] Step S3, evenly applying a brazing flux on the surface of the welding joint, then sleeving a welding ring on the welding joint, and heating the welding joint to form a brazed joint;

[0009] Among them, during the heating process, the welding infrared image is collected in real time to determine the temperature change area, the temperature difference degree of the temperature change area is determined according to the area and temperature range of the temperature change area, and the change synchronization is determined according to the number of temperature change areas;

[0010] The flow rate of the solder ring solder is predicted according to the temperature difference degree, the change synchronization, and the real-time flow rate of the solder ring solder within a preset time period;

[0011] The welding area image is collected in real time to determine whether the flow state of the solder ring is uniform flow or non-uniform flow;

[0012] The heating power or heating time is adjusted according to the flow rate, flow state, thermal conductivity of the solder ring, and pipe material parameters, and the position of the solder ring during the next welding is adjusted according to the flow state;

[0013] Among them, the pipe material parameters include the thermal conductivity of red copper and the thermal conductivity of stainless steel.

[0014] Furthermore, the temperature change area of the welding area is divided based on the temperature distribution of the welding infrared image, and the temperature difference degree is determined based on the area of the temperature change area and the corresponding temperature range.

[0015] Furthermore, the number of temperature change areas is determined according to the temperature distribution corresponding to the temperature change area, and the change synchronization is determined according to the number change curve of the number of temperature change areas.

[0016] Furthermore, the correlation between the temperature difference degree and the flow rate is determined according to the temperature difference degree and the preset difference degree threshold, and a flow rate prediction model is constructed according to the temperature difference degree, the real-time flow rate, the correlation, and the change synchronization to predict the flow rate of the solder ring solder;

[0017] Among them, the change synchronization is positively correlated with the flow rate.

[0018] Furthermore, determining the correlation includes:

[0019] If the temperature difference degree is less than or equal to the preset difference degree threshold, the temperature difference degree is positively correlated with the flow rate;

[0020] If the temperature difference degree is greater than the preset difference degree threshold, the temperature difference degree is negatively correlated with the flow rate.

[0021] Furthermore, the contour points of the solder ring are determined according to the welding area image, and the contour point distance is determined based on the solder ring contour points and the initial solder ring contour points to determine the flow state;

[0022] Among them, a set of real-time welding ring contour points is determined according to the welding ring contour points, and a set of initial welding ring contour points is determined according to the initial welding ring contour points;

[0023] Match the welding ring contour points in the set of real-time welding ring contour points with the initial welding ring contour points in the set of initial welding ring contour points;

[0024] Calculate the distances between each pair of contour points after matching to obtain a distance set, compare the contour point distances with a distance segmentation threshold, and determine the flow state according to the comparison results.

[0025] Furthermore, determine the adjustment method for the heating power or heating time according to the flow state, and determine the adjustment of the welding ring position during the next welding. Among them,

[0026] If the flow state is uniform flow and the flow velocity exceeds the preset flow velocity range, then reduce the heating power or shorten the heating time;

[0027] If the flow state is uniform flow and the flow velocity is lower than the preset flow velocity range, then increase the heating power or extend the heating time;

[0028] If the flow state is uniform flow and the flow velocity conforms to the preset flow velocity range, then do not adjust the heating power and heating time;

[0029] If the flow state is non-uniform flow, then adjust the welding ring position during the next welding according to the circumferential spacing at several positions between the welding ring and the copper tube during the next welding.

[0030] Furthermore, determine an adjustment coefficient according to the preset flow velocity range and the flow velocity, and determine the power adjustment amount of the heating power according to the adjustment coefficient, the thermal conductivity of the welding ring, the thermal conductivity of copper, the thermal conductivity of stainless steel, and the preset heating power.

[0031] Furthermore, determine the heat gap corresponding to the velocity gap according to the preset flow velocity range and the flow velocity, and determine the time adjustment amount of the heating time based on the heat gap and the actual heating power;

[0032] Among them, the flow velocity is positively correlated with the heat.

[0033] Furthermore, determine the spacing consistency according to the circumferential spacing at the several positions to adjust the welding ring position during the next welding.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention uses stainless steel and red copper to form an air-conditioning pipeline, reducing production costs, energy conservation and emission reduction. At the same time, the present invention collects the images of the welding area and the infrared welding images in real time, obtains the temperature difference degree, the temperature change synchronization and the solder ring flow state through image analysis, predicts the flow rate of the solder in the solder ring based on this, and flexibly adjusts the heating power or heating time in combination with factors such as the solder ring material and the pipe material. By optimizing the welding parameters in a timely manner according to the actual welding situation, welding defects such as solder ball accumulation and weld lack of filling are avoided, the solder ring flows evenly and fills the weld fully, forming a smooth, dense and perfectly fused brazed joint, thereby further improving the welding quality and stability, enhancing the strength and sealing performance of the welded part of the stainless steel pipeline for air conditioners, and ensuring the reliable operation of the air-conditioning pipeline system.

[0035] Further, the present invention determines the correlation between the temperature difference degree and the flow rate according to the temperature difference degree and the preset difference degree threshold, which is convenient for the model to capture the influence of temperature change on the solder flow rate. Secondly, the temperature difference degree, the real-time flow rate and the correlation are incorporated into the model construction, fully considering the flow state of the solder and the dynamic change of the flow rate in actual welding. Moreover, the change synchronization is introduced, enabling the model to more comprehensively reflect the real welding phenomenon, thereby more accurately predicting the flow rate of the solder in the solder ring at different stages, providing strong support for the precise control of the welding process, improving the welding quality, and reducing welding defects caused by abnormal solder flow.

[0036] Further, the present invention determines the adjustment method for the heating power or heating time according to the flow state and the flow rate, and determines the adjustment of the solder ring position during the next welding, so that after the solder ring reaches the appropriate melting state, the heating is stopped in time to avoid excessive flow, or the heating power is increased and the heating time is extended to improve the fluidity of the solder ring. At the same time, the present invention adjusts the solder ring position during the next welding, which can avoid too large local weld spacing, so that the solder ring flows evenly and fills the weld fully, forming a smooth, dense and perfectly fused brazed joint, improving the welding quality and stability.

[0037] Further, the present invention precisely adjusts the solder ring position according to the weld distance between the solder ring and the red copper pipe, improving the accuracy and uniformity of the solder ring position, reducing welding defects and quality problems caused by improper solder ring position, thereby improving the welding quality and stability, enhancing the strength and sealing performance of the welded part of the stainless steel pipeline for air conditioners, and ensuring the reliable operation of the air-conditioning pipeline system. Description of the Drawings

[0038] Figure 1 It is a half-sectional view of the stainless steel pipeline for air conditioners according to the embodiment of the present invention;

[0039] Figure 2It is a step diagram of the welding method for the stainless steel pipeline of the air conditioner in the embodiment of the present invention;

[0040] Figure 3 It is a step diagram of adjusting the heating parameters and the position of the welding ring during the welding process in the embodiment of the present invention;

[0041] Figure 4 It is a step diagram of determining the flow rate of the welding ring solder in the embodiment of the present invention;

[0042] In the figure: 1, stainless steel pipe; 2, copper pipe; 3, welding ring. Specific embodiments

[0043] In order to make the purpose and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention and do not limit the protection scope of the present invention.

[0045] It should be noted that in the description of the present invention, the terms indicating the direction or positional relationship such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0046] Please refer to Figure 1 , Figure 2 , Figure 3 as shown, Figure 1 It is a half-sectional view of the stainless steel pipeline for the air conditioner in the embodiment of the present invention; Figure 2 It is a step diagram of the welding method for the stainless steel pipeline of the air conditioner in the embodiment of the present invention; Figure 3 It is a step diagram of adjusting the heating parameters and the position of the welding ring during the welding process in the embodiment of the present invention.

[0047] Specifically, the present invention provides a welding method for a stainless steel pipeline for an air conditioner, including:

[0048] Step S1, pre-treat the ports of the copper pipe 2 and the stainless steel pipe 1 to be welded;

[0049] Step S2, flare the two ends of the stainless steel port, and insert the ports of the copper pipe 2 into the two ends of the flared stainless steel pipe 1 respectively to form a welded joint;

[0050] Step S3: After evenly applying a soldering flux on the surface of the welded joint, slip the solder ring 3 onto the welded joint and heat the welded joint to form a soldered joint;

[0051] Among them, during the heating process, step S3 includes:

[0052] Step S31: Collect welding infrared images in real time to determine the temperature change area, determine the temperature difference degree of the temperature change area according to the area and temperature range of the temperature change area, and determine the change synchronization according to the number of temperature change areas;

[0053] Step S32: Predict the flow rate of the solder in the solder ring according to the temperature difference degree, the change synchronization, and the real-time flow rate of the solder in the solder ring within a preset time period;

[0054] Step S33: Collect welding area images in real time to determine whether the flow state of the solder ring 3 is uniform flow or non-uniform flow;

[0055] Step S34: Adjust the heating power or heating time according to the flow rate, flow state, thermal conductivity of the solder ring, and pipe material parameters, and adjust the position of the solder ring 3 during the next welding according to the flow state;

[0056] Among them, the pipe material parameters include the thermal conductivity of red copper and the thermal conductivity of stainless steel.

[0057] It can be understood that before welding, the two ends of the pipe orifices of the red copper pipe 2 and the stainless steel pipe 1 are pretreated to remove impurities and oxide layers, which can ensure a good welding foundation. Then, the stainless steel pipe 1 is flared and inserted into the red copper pipe 2 to form a welded joint, which can increase the welding area. The pressure resistance effect of stainless steel is 3 times higher than that of red copper, which can improve the service life. The heat dissipation of stainless steel is 3 times worse than that of red copper, and the heat preservation effect is good, which can improve the compression air separation rate and the air conditioner cop (energy efficiency ratio). Moreover, replacing red copper with stainless steel can reduce costs, avoid resource consumption, and achieve energy conservation and emission reduction.

[0058] It can be understood that during the welding process, temperature is the key factor determining the state of the solder ring. As the temperature rises, the solder ring 3 undergoes a transformation from solid state to liquid state. Different temperature distributions and change trends directly affect the melting speed and fluidity of the solder ring 3. For example, when the temperature distribution in the welding area is uniform and rises slowly, the solder ring 3 can be evenly heated, slowly melted, and flow smoothly; on the contrary, if the local temperature is too high, the solder ring 3 will quickly melt in this area, which may lead to too fast flow or even splashing; if the temperature is too low, the solder ring 3 will melt slowly, showing poor fluidity and easily causing insufficient weld filling. By analyzing the temperature distribution, difference degree, and change trend, the melting state and flow trend of the solder ring 3 can be inferred, and thus the welding quality can be indirectly determined, and the heating parameters can be adjusted in a timely manner.

[0059] It can be understood that the respective characteristics of the material of the welding ring 3 and the pipe material play important roles in the welding process. Different materials of the welding ring 3 have different melting points, surface tensions, fluidities, etc. Different pipe materials also have different thermal conductivities and melting points. These parameters will affect the temperature distribution in the welding area. Therefore, adjusting the heating power and time in combination with the material characteristics can meet the welding requirements of different material combinations and achieve good welding effects.

[0060] In a specific embodiment, the value range of the preset time period is 0.5 s to 2 s. Preferably, the value of the preset time period is 1 s. The Vickers hardness value range of the stainless steel pipe 1 is 130 to 150. The material of the welding ring 3 is brass. In practice, the value range and the preferred value of the preset time period can be determined according to the actual situation, and no specific limitation is made here and will not be elaborated further.

[0061] The present invention uses stainless steel and red copper to be connected to form an air-conditioning pipeline, reducing production costs, energy conservation and emission reduction. At the same time, the present invention collects the welding area image and the welding infrared image in real time, obtains the temperature difference degree, the temperature change synchronism and the flow state of the welding ring 3 through image analysis, thereby predicting the flow rate of the welding ring solder, and combining factors such as the material of the welding ring 3 and the pipe material, flexibly adjusting the heating power or the heating time. By optimizing the welding parameters in time according to the actual welding situation, welding defects such as weld bead accumulation and weld seam lack of filling are avoided, so that the welding ring 3 flows evenly and fills the weld seam sufficiently, forming a smooth, dense and perfectly fused brazed joint, thereby further improving the welding quality and stability, enhancing the strength and sealing performance of the welded part of the stainless steel pipeline for air conditioners, and ensuring the reliable operation of the air-conditioning pipeline system.

[0062] Specifically, the temperature change area of the welding area is divided based on the temperature distribution of the welding infrared image, and the temperature difference degree is determined based on the area of the temperature change area and the corresponding temperature range.

[0063] It can be understood that during the welding process, since the welding ring 3 is annular, the temperatures of different parts are different. The infrared image can reflect the temperature distribution during the welding heating process, and the entire welding area can be divided into different temperature change areas according to the temperature level and change trend to determine the temperature difference degree. Moreover, the larger the area of the temperature change area, it indicates that a relatively large area is in this temperature state during the welding process, which will have a relatively greater impact on the welding quality and affect the welding effect. Therefore, comprehensively considering the area of the temperature change area and the corresponding temperature range can comprehensively evaluate the temperature difference degree in the welding area, which is convenient for subsequent evaluation of the flow rate of the welding ring solder.

[0064] In a specific embodiment, a welding infrared image can be collected by an infrared thermal imager. Different colors or gray values in the infrared image correspond to different temperatures. An image segmentation algorithm is used to process the welding infrared image. Based on principles such as pixel similarity and clustering analysis, regions with similar temperatures can be divided into a temperature-changing region. The area of the temperature-changing region is determined by counting the number of pixel points within the temperature-changing region. The temperature range within the temperature-changing region can be determined by obtaining the highest temperature and the lowest temperature within the temperature-changing region. The sum of the weighted temperature values of all temperature-changing regions = , where n is the number of temperature-changing regions, and i = 1, 2,.., n. The temperature characterization value of a single temperature-changing region is the average of the highest temperature and the lowest temperature within the single temperature-changing region. The degree of temperature difference is:

[0065] , it can be understood that the greater the degree of temperature difference, the higher the temperature difference degree of the welding region. In practice, the technical means for determining the temperature-changing region can be selected according to the actual situation, which is not specifically limited here and will not be elaborated further.

[0066] Specifically, the number of temperature-changing regions is determined according to the temperature distribution corresponding to the temperature-changing region, and the change synchronization is determined according to the number change curve of the number of temperature-changing regions.

[0067] It can be understood that if the number of temperature-changing regions gradually decreases, it indicates that the temperature of the welding region tends to be unified. If the number of temperature-changing regions gradually increases, it indicates that the temperature difference in the welding region is relatively large, which will affect the solder flow and welding quality of the solder ring 3. Therefore, based on the number of temperature-changing regions of the temperature-changing region, the change synchronization of the temperatures of each temperature-changing region can be determined.

[0068] In a specific embodiment, at different times, the welding infrared image is collected by an infrared thermal imager and segmented to determine the number of temperature-changing regions at the corresponding time. Taking the acquisition time as the abscissa and the corresponding number of temperature-changing regions as the ordinate, a number change curve is constructed, and the slope of the number change curve is used as the change synchronization.

[0069] Please refer to Figure 4 shown, which is a step diagram for determining the solder flow rate of the solder ring in an embodiment of the present invention; specifically, the correlation between the temperature difference degree and the flow rate is determined according to the temperature difference degree and the preset difference degree threshold. A flow rate prediction model is constructed based on the temperature difference degree, the real-time flow rate, the correlation, and the change synchronization to predict the solder flow rate of the solder ring;

[0070] Among them, the change synchronization is positively correlated with the flow rate.

[0071] It can be understood that under certain conditions, the degree of temperature difference is positively correlated with the flow rate of the solder in the solder ring, but not absolutely. Therefore, under the limitation of the relationship between the preset difference degree threshold and the degree of temperature difference, determining the correlation between the degree of temperature difference and the flow rate plays a key role in constructing the flow rate prediction model. And the change synchrony characterizes the consistency of temperature change over time in each temperature change region. When the change synchrony is good, it indicates that the temperature of the entire welding area rises or falls uniformly, and the melting and flow of each part of the solder ring 3 are relatively uniform and coordinated, and the fluidity is relatively good. On the contrary, if the change synchrony is poor, it will affect the smooth flow of the solder in the solder ring, and then lead to a decrease in the flow rate of the solder in the solder ring. The real-time flow rate is the result of the combined action of the degree of temperature difference and the change synchrony, and can be used as an important basis when constructing the prediction model.

[0072] In a specific embodiment, the value range of the preset difference degree threshold is 2 to 3. Preferably, the value of the preset difference degree threshold is 2.5. A mathematical model is established with the degree of temperature difference, change synchrony, and corresponding time points as input features, the correlation and the positive correlation between change synchrony and flow rate as limiting conditions, and the real-time flow rate within a preset time period as the output feature. A neural network model is used to establish the flow rate prediction model to determine the specific functional relationship between the degree of temperature difference, real-time flow rate, and the relationship between change synchrony and flow rate, and obtain the predicted flow rate of the solder in the solder ring. In practice, the value range and preferred value of the preset difference degree threshold can be determined according to the actual situation, and no specific limitation is made here, nor will it be elaborated further.

[0073] The present invention determines the correlation between the degree of temperature difference and the flow rate according to the degree of temperature difference and the preset difference degree threshold, which facilitates the model to capture the influence of temperature change on the flow rate of the solder. Secondly, the degree of temperature difference, real-time flow rate, and correlation are incorporated into the model construction, fully considering the flow state of the solder and the dynamic change of the flow rate in actual welding. Furthermore, the change synchrony is introduced, enabling the model to more comprehensively reflect the real welding phenomenon, thereby more accurately predicting the flow rate of the solder in the solder ring at different stages, providing strong support for the precise control of the welding process, improving the welding quality, and reducing welding defects caused by abnormal solder flow at the same time.

[0074] Specifically, determining the said correlation includes:

[0075] If the degree of temperature difference is less than or equal to the preset difference degree threshold, the degree of temperature difference and the flow rate are positively correlated;

[0076] If the degree of temperature difference is greater than the preset difference degree threshold, the degree of temperature difference and the flow rate are negatively correlated.

[0077] It can be understood that when there is a temperature difference, heat will transfer from the high-temperature region to the low-temperature region, which will cause the melting degree and speed of the solder in the solder ring to be different at different positions. The greater the degree of temperature difference, the greater the temperature difference between the high-temperature region and the low-temperature region, and the greater the thermal driving force. Under the action of the thermal driving force, the solder will flow from the high-temperature region to the low-temperature region to achieve thermal equilibrium. Therefore, in this case, the degree of temperature difference is positively correlated with the flow velocity.

[0078] It can be understood that if the degree of temperature difference is too large and exceeds the preset difference degree threshold, the excessive temperature difference will cause the solder ring 3 to overheat in a local area, resulting in changes in the physical properties of the solder ring 3, such as increased viscosity, intensified oxidation, etc. These factors will instead hinder the solder flow and reduce the flow velocity. In addition, if the degree of temperature difference is too large, it may also cause unstable phenomena such as eddy currents and turbulence in the process of solder flow, which will also affect the flow velocity of the solder. Therefore, in this case, the degree of temperature difference is negatively correlated with the flow velocity.

[0079] Specifically, determine the solder ring contour points according to the welding area image, and determine the contour point distance based on the solder ring contour points and the initial solder ring contour points to judge the flow state;

[0080] Among them, determine the real-time solder ring contour point set according to the solder ring contour points, and determine the initial solder ring contour point set according to the initial solder ring contour points;

[0081] Match the solder ring contour points in the real-time solder ring contour point set with the initial solder ring contour points in the initial solder ring contour point set;

[0082] Calculate the distance between each pair of contour points after matching to obtain a distance set, and compare the contour point distance with the distance segmentation threshold, and determine the flow state according to the comparison result.

[0083] It can be understood that when the solder ring 3 is not melted, its shape is a regular ring. As the temperature rises, the solder ring 3 begins to melt, and the edge of the solder ring 3 will become blurred and the shape will change. By extracting the contour information of the solder ring 3 and comparing the contour shapes at different times, it can be judged whether the solder ring 3 has started to melt and the degree of melting.

[0084] In a specific embodiment, an initial weld ring contour can be extracted based on the initially captured image of the welding area. After graying and noise reduction processing of the welding area image, according to the gray difference between the welding area and the background, the OTSU threshold method is used to segment the image into two parts: the welding area and the background. Then, edge detection is performed on the segmented image, such as using edge detection operators like Sobel and Canny, to determine the gradient values and directions of each pixel point in the welding area image, and further find the pixel points with larger gray value changes as edge points. Subsequently, a contour extraction algorithm, such as a contour tracking algorithm based on chain codes, is used to extract the complete weld ring contour from the edge points. After refining the weld ring contour, redundant points on the contour are removed to obtain a set of weld ring contour points. In practice, the method for determining the weld ring contour points can be selected according to the actual situation, which is not specifically limited here and will not be elaborated further.

[0085] In another specific embodiment, for the set of weld ring contour points and the set of initial weld ring contour points at a certain moment, the nearest neighbor matching algorithm is used to match the current contour points with the points that are the closest in distance among the initial contour points. By calculating the distances between each pair of contour points after matching, a corresponding distance set can be obtained. The Euclidean distance can be used to determine the contour point distance for each pair of contour points. The contour point distances determined at the same moment are compared with a distance segmentation threshold, and the flow state is determined according to the comparison result. The distance segmentation threshold is the mean value of the contour point distances at the same moment. If the number of contour point distances greater than or equal to the distance segmentation threshold determined based on the welding area image is greater than a preset number threshold, the flow state is determined to be uniform flow; otherwise, it is non-uniform flow. The value range of the preset number threshold is 4 / 6 to 5 / 6 of the number of weld ring contour points determined for the corresponding welding area image, and the value of the preset number threshold is 9 / 12 of the number of weld ring contour points determined for the corresponding welding area image. In practice, the value ranges and preferred values of the distance segmentation threshold and the preset number threshold can be determined according to the actual situation, which is not specifically limited here. As long as it is ensured that the preset number threshold is determined according to the number of weld ring contour points determined for the welding area image, it will not be elaborated further here.

[0086] Specifically, according to the flow state, the adjustment method for the heating power or heating time is determined, and the adjustment of the position of the weld ring 3 during the next welding is determined, where

[0087] If the flow state is uniform flow and the flow velocity exceeds the preset flow velocity range, the heating power is reduced or the heating time is shortened;

[0088] If the flow state is uniform flow and the flow velocity is lower than the preset flow velocity range, the heating power is increased or the heating time is extended;

[0089] If the flow state is uniform flow and the flow velocity conforms to the preset flow velocity range, the heating power and heating time are not adjusted;

[0090] If the flow state is non-uniform flow, the position of the solder ring 3 during the next welding is adjusted according to the circumferential spacing at several positions between the solder ring 3 and the copper pipe 2 during the next welding.

[0091] It can be understood that an appropriate flow velocity can make the solder uniformly fill the weld gap between the stainless steel and the copper. If the flow velocity is too fast, the solder will be unevenly distributed in the weld, resulting in local accumulation or incomplete filling, which will affect the strength and sealing performance of the welded joint. If the flow velocity is too slow, the solder will not be able to fill the weld in time, forming voids or gaps, reducing the welding quality. When the flow velocity of the solder in the solder ring is too fast, it may be that the heating power is too high, resulting in too high a temperature of the solder ring 3 and a decrease in viscosity, thus having strong fluidity. At this time, the heating power should be reduced to reduce the input heat, thereby slowing down the flow velocity. At the same time, reducing the heating time can also prevent the solder ring 3 from being overheated. For some solder ring 3 materials with strong thermal sensitivity, too long a heating time will cause its fluidity to increase sharply. If the flow velocity of the solder in the solder ring is too slow, it may be that the heating power is insufficient, resulting in the solder ring 3 not melting. Increasing the heating power can increase the heat input and promote the flow of the solder in the solder ring. Similarly, extending the heating time can also ensure sufficient heat transfer and melt the solder ring 3.

[0092] It can be understood that if the flow state is non-uniform, it means that the axes of the solder ring 3 and the welded pipe are not on the same axis at the beginning, which is likely to cause the situation of too large or too small local weld spacing. Adjusting the position of the solder ring 3 before welding can improve the welding quality.

[0093] In a specific embodiment, the preset flow velocity range is 2 mm / s to 6 mm / s. Preferably, the preset flow velocity range is 3 mm / s to 5 mm / s. In practice, the value range of the preset flow velocity range can be determined according to the specific material of the solder ring 3, which is not specifically limited here and will not be elaborated further.

[0094] The present invention determines the adjustment method of the heating power or heating time according to the flow state and flow velocity, and determines the adjustment of the position of the solder ring 3 during the next welding, so that after the solder ring 3 reaches the appropriate melting state, the heating is stopped in time to avoid too fast flow, or the heating power is increased and the heating time is extended to improve the fluidity of the solder ring 3. At the same time, the present invention adjusts the position of the solder ring 3 during the next welding, which can avoid too large local weld spacing, so that the solder in the solder ring 3 flows uniformly and fills the weld fully, forming a smooth, dense and perfectly fused brazed joint, improving the welding quality and stability.

[0095] Specifically, an adjustment coefficient is determined according to the preset flow velocity range and the flow velocity. The power adjustment amount of the heating power is determined according to the adjustment coefficient, the thermal conductivity of the welding ring, the thermal conductivity of copper, the thermal conductivity of stainless steel, and the preset heating power.

[0096] In a specific embodiment, the preset flow velocity characterization value is the average of the highest flow velocity and the lowest flow velocity in the preset flow velocity range. The adjustment coefficient = , and the power adjustment amount of the heating power = adjustment coefficient × preset heating power × . The average of the thermal conductivity of copper and the thermal conductivity of stainless steel is the average thermal conductivity. The value range of the preset heating power is 500W - 800W. Preferably, the value of the preset heating power is 600W - 700W. In practice, the value range and the preferred value of the preset heating power and the adjustment coefficient can be determined according to the actual situation, and no specific limitation is made here and will not be elaborated further.

[0097] Specifically, the heat gap corresponding to the speed gap is determined according to the preset flow velocity range and the flow velocity. Based on the heat gap and the actual heating power, the time adjustment amount of the heating time is determined;

[0098] wherein, the flow velocity is positively correlated with the heat.

[0099] It can be understood that if the flow state is uniform but the speed is slow, it indicates that the overall heat is insufficient and the heating time needs to be extended. On the contrary, if the flow velocity is fast, it means that the heat is excessive and the heating time can be appropriately shortened.

[0100] In a specific embodiment, the time adjustment amount of the heating time is the ratio of the heat gap to the actual heating power. Based on the heat conduction formula, the heat range corresponding to the preset flow velocity range can be obtained. According to the flow velocity and the heat conduction formula, the actual heat corresponding to the flow velocity can be determined. The heat gap is the difference between the average of the heat range and the actual heat range.

[0101] Specifically, the spacing consistency is determined according to the circumferential spacing at the several positions to adjust the position of the welding ring 3 during the next welding.

[0102] It can be understood that by adjusting the position of the welding ring 3, the distribution of the welding ring 3 in the circumferential direction can be made more uniform and reasonable, which helps to achieve uniform welding and reduce welding defects caused by the position deviation of the welding ring 3. If the position of the welding ring 3 is deviated and not on the same axis as the position of the welded pipe, it is likely to affect the welding quality and cause defect problems such as weld seams.

[0103] In a specific embodiment, a high-precision measuring instrument, such as a laser rangefinder or an optical measuring device, is adopted to accurately measure the gap distance, i.e., the circumferential pitch, between the copper tube 2 and the welding ring 3 corresponding to several positions. The pitch consistency is determined by calculating the average value of several circumferential pitches. If the number of circumferential pitches exceeding the average value is greater than 1 / 2 of the total number of circumferential pitches, the position of the welding ring 3 during the next welding is adjusted, and the adjustment direction is determined according to the circumferential pitch to reduce the pitch deviation and make the circumferential pitch as uniform as possible.

[0104] The present invention accurately adjusts the position of the welding ring 3 according to the weld distance between the welding ring 3 and the copper tube 2, improves the accuracy and uniformity of the position of the welding ring 3, reduces welding defects and quality problems caused by improper position of the welding ring 3, thereby improving the welding quality and stability, enhancing the strength and sealing performance of the welded joint of the stainless steel pipeline for air conditioners, and ensuring the reliable operation of the air conditioner pipeline system.

[0105] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A welding method for stainless steel pipes for air conditioners, characterized in that: include: Step S1, pre-treating the copper tube port and the stainless steel tube port to be welded; Step S2, expanding both ends of the stainless steel port, and inserting the copper tube port into the expanded ports at both ends of the stainless steel tube, respectively, to form a welding joint; Step S3, after evenly applying the brazing flux on the surface of the welding joint, putting the welding ring on the welding joint, and heating the welding joint to form a brazed joint; In the heating process, the welding infrared image is collected in real time to determine the temperature change area, the temperature difference degree of the temperature change area is determined according to the area and temperature range of the temperature change area, and the change synchronization is determined according to the number of temperature change areas; Predicting the flow velocity of the solder ring solder according to the degree of temperature difference, the synchronization of the change and the real-time flow velocity of the solder ring solder within a preset time period; Real-time acquisition of welding area images to determine whether the flow state of the welding ring is uniform flow or non-uniform flow; Adjusting the heating power or heating time according to the flow velocity, flow state, thermal conductivity of the welding ring and pipe parameters, and determining the welding ring position before the next welding according to the flow state; Wherein, the pipe material parameters include the thermal conductivity of copper and the thermal conductivity of stainless steel; The adjustment coefficient is determined according to the preset flow velocity range and the flow velocity, and the power adjustment amount of the heating power is determined according to the adjustment coefficient, the thermal conductivity of the welding ring, the thermal conductivity of the copper, the thermal conductivity of the stainless steel and the preset heating power; the adjustment coefficient = The power adjustment amount of the heating power = adjustment coefficient × preset heating power × The average of the thermal conductivity of copper and the thermal conductivity of stainless steel is the average of the thermal conductivity, and the preset flow velocity characterization value is the average of the highest flow velocity and the lowest flow velocity in the preset flow velocity range.

2. The welding method for stainless steel pipes for air conditioners according to claim 1, characterized in that: The welding area is divided into temperature change areas based on the temperature distribution of the welding infrared image, and the degree of temperature difference is determined based on the area of ​​the temperature change area and the corresponding temperature range.

3. The welding method for stainless steel pipes for air conditioners according to claim 2, characterized in that: The number of temperature change regions is determined according to the temperature distribution corresponding to the temperature change regions, and the change synchronization is determined according to the number change curve of the number of temperature change regions.

4. The welding method for stainless steel pipes for air conditioners according to claim 3, characterized in that: Determine the correlation between the temperature difference degree and the flow velocity according to the temperature difference degree and the preset difference degree threshold, and construct a flow velocity prediction model according to the temperature difference degree, the real-time flow velocity, the correlation and the change synchronization to predict the flow velocity of the solder ring; The change synchronization is positively correlated with the flow speed.

5. The welding method for stainless steel pipes for air conditioners according to claim 4, characterized in that: Determining the correlation includes: If the temperature difference is less than or equal to the preset difference threshold, the temperature difference is positively correlated with the flow velocity; If the temperature difference is greater than the preset difference threshold, the temperature difference is negatively correlated with the flow velocity.

6. The welding method for stainless steel pipes for air conditioners according to claim 1, characterized in that: Determine a weld ring contour point according to the weld area image, and determine a contour point distance based on the weld ring contour point and an initial weld ring contour point to determine a flow state; Wherein, a real-time weld ring contour point set is determined according to the weld ring contour points, and an initial weld ring contour point set is determined according to the initial weld ring contour points; Matching the weld ring contour points in the real-time weld ring contour point set with the initial weld ring contour points in the initial weld ring contour point set; The distance between each pair of contour points after matching is calculated to obtain a distance set, and the contour point distance is compared with a distance segmentation threshold, and the flow state is determined according to the comparison result.

7. The welding method for stainless steel pipes for air conditioners according to claim 6, characterized in that: Determine the adjustment method of heating power or heating time according to the flow state, and adjust the welding ring position before the next welding, including: If the flow state is uniform flow and the flow speed exceeds the preset flow speed range, reducing the heating power or shortening the heating time; If the flow state is uniform flow and the flow speed is lower than the preset flow speed range, increasing the heating power or extending the heating time; If the flow state is uniform flow and the flow speed is within the preset flow speed range, the heating power and the heating time are not adjusted; If the flow state is non-uniform flow, the position of the welding ring before the next welding is determined according to the circumferential spacing between the welding ring and the copper tube at several positions during the next welding.

8. The welding method for stainless steel pipes for air conditioners according to claim 7, characterized in that: Determine a heat difference corresponding to the speed difference according to the preset flow speed range and the flow speed, and determine a time adjustment amount of the heating time based on the heat difference and the actual heating power; The flow velocity and heat are positively correlated.

9. The welding method for stainless steel pipes for air conditioners according to claim 7, characterized in that: The spacing consistency is determined based on the circumferential spacing at a plurality of positions so as to adjust the welding ring position during the next welding.

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