An automatic welding method and welding system for air-conditioning pipelines

Abstract

The present invention relates to an automatic welding method and welding system for air-conditioning pipelines. The method includes arc starting stage welding: determining arc starting welding parameters according to the first physical parameters and the first environmental parameters, and performing arc starting stage welding; self-adjusting stage welding includes: determining an adjustment strategy according to the second physical parameters, and performing real-time adjustment of the welding parameters according to the adjustment strategy to carry out self-adjusting stage welding; arc ending stage welding includes: determining arc ending welding parameters according to the welding parameters in the self-adjusting stage, and performing arc ending stage welding. In the welding process of the present invention, relevant parameters are collected in real time and the welding parameters of automatic welding are adjusted in real time according to the relevant parameters. By collecting relevant parameters of the molten pool, current, voltage and other parameters in real time and dynamically adjusting the welding energy input, the thermal conductivity difference between copper and stainless steel can be effectively overcome, the occurrence probability of defects such as pores and cracks can be reduced, and the reliability of automatic welding can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic welding, and particularly to an automatic welding method and welding system for air-conditioning pipelines. Background Art

[0002] The pipelines of air conditioners and heat exchangers generally use copper tubes, aluminum tubes and iron tubes. These materials not only have high procurement costs, but also have poor corrosion resistance and pressure resistance. At present, there is also a solution to use stainless steel to replace copper products to manufacture composite tubes by welding, but the welding method is relatively simple and not mature enough.

[0003] For example, Chinese Patent Publication No. CN114110284A discloses a stainless steel air-conditioning pipeline, which includes a welded stainless steel pipe body (the materials include SUS304 / 304L, SUS436 / 436J1L, SUS409 / 409L). A copper connecting pipe and a stainless steel connecting pipe are welded above the welded stainless steel pipe body, or copper connecting pipes and stainless steel connecting pipes are welded at both ends respectively. It can be applied in various pipelines, and can greatly reduce the use of copper tubes. It can be applied to stainless steel gas (water) collecting pipes, mufflers, filters, three-way pipes, U-shaped pipes, and has a wide range of applications. The stainless steel pipe has good corrosion resistance, strong pressure resistance and tensile strength. It can greatly reduce the manufacturing cost and improve the service life of the product. Adopting a unique welding technology ensures that the metal filler metal forms good wettability and spreadability, increases the strength and sealing performance of the weld, the weld formation is beautiful, does not leak, the product has strong corrosion resistance and high pressure resistance, effectively reduces the use of copper tubes on the air-conditioning pipeline, greatly reduces the manufacturing cost, has high social and economic benefits and strong practicability. Thus, the existing technology replaces copper with stainless steel and welds to produce composite pipes through welding technology, but its welding process or procedure only simply sets relevant physical parameters or electrical parameters, and welds according to the set parameters during the whole welding process, without considering that the states of the copper tube and the stainless steel tube change during the welding process, and the same or preset parameters cannot adapt to the state changes of the copper tube and the stainless steel tube and the whole welding process flow, resulting in defects such as cracks and pores in the welding, and low reliability. Summary of the Invention

[0004] Therefore, the present invention provides an automatic welding method and welding system for air-conditioning pipelines to overcome the problems in the prior art that the welding process flow cannot be adjusted according to the real-time state changes of the copper tube and the stainless steel tube during the welding process, resulting in unstable welding strength and low reliability.

[0005] To achieve the above object, the present invention provides an automatic welding method for air-conditioning pipelines, including:

[0006] Obtain the first physical parameters and the first environmental parameters of the copper tube to be welded and the stainless steel tube to be welded. Among them, the first physical parameters include the thickness of the welded part of the stainless steel tube, the thickness of the welded part of the copper tube, and the wire diameter, and the first environmental parameters include air humidity, air temperature, and the concentration of acidic gases in the air;

[0007] Determine the starting arc welding parameters according to the first physical parameters and the first environmental parameters, and perform welding in the starting arc stage according to the starting arc welding parameters;

[0008] When the welding in the starting arc stage is completed, perform welding in the self-adjustment stage,

[0009] Obtain the second physical parameters of the molten pool in real time. Among them, the second physical parameters include the surface temperature of each position of the molten pool;

[0010] Determine the characteristics of the welding molten pool according to the second physical parameters, and judge whether to adjust the welding parameters in real time based on the molten pool parameters corresponding to the characteristics of the welding molten pool. Perform welding in the self-adjustment stage according to the welding parameters adjusted in real time. Among them, the characteristics of the welding molten pool include the first boundary of the molten pool close to the copper tube side and the second boundary of the molten pool close to the stainless steel tube side, and the molten pool parameters include the surface area of the molten pool and the surface temperature of the molten pool;

[0011] When the welding in the self-adjustment stage is completed, enter the arc extinguishing stage for welding. Determine the arc extinguishing welding parameters according to the welding parameters in the self-adjustment stage, and perform welding in the arc extinguishing stage according to the arc extinguishing welding parameters.

[0012] Further, the process of determining the starting arc welding parameters according to the first physical parameters and the first environmental parameters includes:

[0013] Determine the starting arc voltage according to the thickness of the welded part of the stainless steel tube and the thickness of the welded part of the copper tube, determine the starting arc current according to the wire diameter, determine the starting arc length according to the starting arc voltage and the starting arc current, and determine the initial wire feeding speed according to the starting arc current;

[0014] Determine the nozzle diameter of the shielding gas according to the starting arc current, the starting arc voltage, and the starting arc length;

[0015] Determine the initial shielding gas flow rate according to the air humidity, the air temperature, the concentration of acidic gases in the air, and the nozzle diameter.

[0016] Further, the process of determining the starting arc voltage according to the thickness of the welded part of the stainless steel tube and the thickness of the welded part of the copper tube includes:

[0017] Determine the average thickness of the welded part according to the thickness of the welded part of the stainless steel tube and the thickness of the welded part of the copper tube;

[0018] Determine the welding proportionality coefficient according to the average thickness;

[0019] Determine the starting arc voltage based on the welding ratio coefficient and the base voltage.

[0020] Further, the process of determining the starting arc current according to the wire diameter includes: determining the distribution coefficient according to the thickness of the welded part of the stainless steel pipe and the thickness of the welded part of the copper pipe, and determining the starting arc current according to the current coefficient per unit thickness, the distribution coefficient, and the wire diameter.

[0021] Further, the process of determining the initial protective gas flow rate according to the air humidity, air temperature, and concentration of acidic gas in the air includes:

[0022] Determine the base flow rate of the protective gas according to the welding speed and the nozzle diameter, determine the humidity correction value, temperature correction value, and acidic gas correction value respectively according to the air humidity, air temperature, and concentration of acidic gas in the air, and determine the initial protective gas flow rate according to the base flow rate, humidity correction value, temperature correction value, and acidic gas correction value.

[0023] Further, the process of determining the welding pool characteristics of the molten pool includes:

[0024] Identify the isotherms on the copper pipe side and the isotherms on the stainless steel pipe side corresponding to the molten pool respectively, take the isotherm corresponding to the first temperature on the copper pipe side as the first boundary of the molten pool, take the isotherm corresponding to the second temperature on the stainless steel pipe side as the second boundary of the molten pool, and determine the surface area of the molten pool according to the first boundary and the second boundary of the molten pool.

[0025] Uniformly set a number of monitoring points between the center of the molten pool and the first boundary and the second boundary of the molten pool and obtain the temperatures of the monitoring points, and determine the surface temperature of the molten pool according to the temperatures of the monitoring points.

[0026] Further, the process of determining whether to adjust the welding parameters in real time based on the molten pool parameters corresponding to the welding molten pool characteristics includes:

[0027] Determine whether to adjust the welding current and / or welding speed according to the comparison result between the surface temperature of the molten pool and the preset temperature range;

[0028] Determine whether to adjust the welding voltage and / or arc length according to the comparison result between the surface area of the molten pool and the preset area range.

[0029] Further, it also includes: adjusting the wire feeding speed according to the welding speed and welding current in the self-adjustment stage, and dynamically adjusting the current protective gas flow rate according to the welding speed, the surface temperature of the molten pool, and the initial protective gas flow rate in the self-adjustment stage.

[0030] Further, the process of determining the arc extinguishing welding parameters according to the welding parameters in the self-adjustment stage includes:

[0031] Determine the arc extinguishing current according to the welding current in the self - adjustment stage, where the arc extinguishing current is positively correlated with the welding current in the self - adjustment stage. Determine the arc extinguishing voltage according to the welding voltage in the self - adjustment stage, where the arc extinguishing voltage is positively correlated with the welding voltage in the self - adjustment stage.

[0032] On the other hand, the present invention also provides an automatic welding system for air - conditioning pipelines, including:

[0033] A data acquisition module for acquiring the first physical parameters and the first environmental parameters of the copper pipe and the stainless - steel pipe to be welded, and for acquiring the second physical parameters of the molten pool in real - time;

[0034] An arc - starting welding parameter determination module connected to the data acquisition module for determining the arc - starting welding parameters according to the first physical parameters and the first environmental parameters;

[0035] A self - adjustment strategy analysis module connected to the data acquisition module for determining the characteristics of the welding molten pool according to the second physical parameters, and for judging whether it is necessary to adjust the welding parameters in real - time based on the molten pool parameters corresponding to the characteristics of the welding molten pool;

[0036] An arc - extinguishing welding parameter determination module connected to the data acquisition module for determining the arc - extinguishing welding parameters according to the welding parameters in the self - adjustment stage;

[0037] An automatic welding device respectively connected to the arc - starting welding parameter determination module, the self - adjustment strategy analysis module, and the arc - extinguishing welding parameter determination module for welding the copper pipe to be welded and the stainless - steel pipe to be welded according to the welding parameters in the arc - starting stage, the self - adjustment stage, and the arc - extinguishing stage.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0039] The automatic welding method and welding system for air - conditioning pipelines of the present invention use stainless steel to replace copper and weld to produce composite pipes through automatic welding technology. During the welding process, relevant parameters are collected in real - time and the welding parameters of the automatic welding are adjusted in real - time according to the relevant parameters. By collecting relevant parameters such as the parameters of the molten pool, current, and voltage in real - time and dynamically adjusting the welding energy input, the thermal conductivity difference between copper and stainless steel can be effectively overcome, the occurrence probability of defects such as pores and cracks can be reduced, and the reliability of automatic welding can be improved.

[0040] Furthermore, the present invention matches the gas flow rate through environmental parameters and nozzle diameter, which can effectively isolate moisture and acidic gases in the air, avoid hydrogen embrittlement, nitridation, or sulfide pollution of the molten pool. By matching the nozzle diameter and flow rate, the waste caused by excessive gas supply during the arc - starting stage can be avoided, and at the same time, the protection failure caused by insufficient flow rate can be prevented. During the welding process, the flow rate of the shielding gas is dynamically adjusted according to the welding speed and the surface temperature of the molten pool, significantly reducing the porosity and surface oxidation.

[0041] Furthermore, the thermal conductivity of stainless steel and copper varies significantly. In the present invention, stainless steel and copper are welded. Based on the average thickness, the starting arc voltage is corrected by a proportionality coefficient to dynamically balance the heat requirements of stainless steel and copper, avoiding insufficient penetration on the copper side due to excessive heat dissipation and preventing intergranular corrosion caused by overheating on the stainless steel side.

[0042] Furthermore, the present invention adjusts the welding current and / or welding speed based on the surface temperature of the molten pool. The surface temperature of the molten pool directly reflects the heat input. When it is detected that the temperature exceeds the preset range, it indicates that the temperature is too high, and the welding current and / or welding speed are automatically adjusted to reduce the heat input per unit length and avoid burn-through or grain coarsening. When the temperature is too low, reverse adjustment is performed to ensure that the penetration meets the standard.

[0043] Furthermore, the present invention adjusts the welding voltage and / or arc length based on the surface area of the molten pool. The surface area of the molten pool reflects the state of arc energy distribution. An overly large surface area indicates that the arc is divergent. The voltage is reduced or the arc length is shortened to increase the arc energy density and suppress the excessive spreading of the molten pool. When the surface area is too small, reverse adjustment is performed to avoid incomplete fusion defects.

[0044] Furthermore, the method and system of the present invention obtain the second physical parameters of the molten pool in real time through a data acquisition module. When deformation is caused by the difference in the thermal expansion coefficients of copper / steel, the welding parameters can be automatically compensated to ensure the stability and quality of welding.

[0045] Furthermore, the air-conditioning pipeline of the present invention uses stainless steel instead of copper, significantly reducing the material cost. Combining real-time parameter adjustment reduces the rejection rate of products, and cooperating with automatic welding control achieves synergistic optimization of cost reduction and efficiency improvement. Description of the Drawings

[0046] Figure 1 is the overall flowchart of the method of the embodiment of the present invention;

[0047] Figure 2 is the adjustment flowchart of determining the welding current and / or welding speed according to the surface temperature of the molten pool and the preset temperature range in the embodiment of the present invention;

[0048] Figure 3 is the adjustment flowchart of determining the welding voltage and / or arc length according to the surface area of the molten pool and the preset area range in the embodiment of the present invention;

[0049] Figure 4 is the adjustment flowchart of determining the welding current and / or welding speed according to the temperature of the molten pool and the preset temperature range in the embodiment of the present invention;

[0050] Figure 5 is the adjustment flowchart of determining the welding speed and / or welding current according to the length of the molten pool and the preset length range in the embodiment of the present invention;

[0051] Figure 6 This is a flowchart for adjusting the welding voltage and / or arc length according to the molten pool width and a preset width range in an embodiment of the present invention;

[0052] Figure 7 This is a flowchart for adjusting the welding current and / or welding speed according to the molten pool depth and a preset depth range in an embodiment of the present invention;

[0053] Figure 8 This is a schematic diagram of the system structure in an embodiment of the present invention;

[0054] Figure 9 This is a block diagram of the structure of an electronic device in an embodiment of the present invention. Detailed implementation manners

[0055] In order to make the objectives and advantages of the present invention more clear and understandable, 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.

[0056] The preferred implementation manners of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0057] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships 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.

[0058] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0059] In the welding method referred to in the present invention, the copper pipe to be welded and the stainless steel pipe to be welded are both round pipes. The movement mode of the welding rod is circular movement, and the angle between the axis of the welding rod and the tangent direction of the weld is 75° - 85°.

[0060] Please refer to Figure 1 As shown, an embodiment of the present invention provides an automatic welding method for air-conditioning pipelines, including:

[0061] Step S1, obtain the first physical parameters and the first environmental parameters of the copper pipe to be welded and the stainless steel pipe to be welded. Among them, the first physical parameters include the thickness of the welding part of the stainless steel pipe, the thickness of the welding part of the copper pipe, and the wire diameter, and the first environmental parameters include air humidity, air temperature, and the concentration of acidic gases in the air;

[0062] Step S2, determine the starting arc welding parameters according to the first physical parameters and the first environmental parameters, and perform welding in the starting arc stage according to the starting arc welding parameters;

[0063] Step S3, when the welding in the starting arc stage is completed, perform welding in the self-adjustment stage. Among them,

[0064] Step S31, obtain the second physical parameters of the molten pool in real time. Among them, the second physical parameters include the surface temperature of each position of the molten pool;

[0065] Step S32, determine the characteristics of the welding molten pool according to the second physical parameters, and judge whether to adjust the welding parameters in real time based on the molten pool parameters corresponding to the characteristics of the welding molten pool. Perform welding in the self-adjustment stage according to the welding parameters adjusted in real time. Among them, the characteristics of the welding molten pool include the first boundary of the molten pool close to the copper pipe side and the second boundary of the molten pool close to the stainless steel pipe side, and the molten pool parameters include the molten pool surface area and the molten pool surface temperature;

[0066] Step S4, when the welding in the self-adjustment stage is completed, enter the arc extinguishing stage for welding. Determine the arc extinguishing welding parameters according to the welding parameters in the self-adjustment stage, and perform welding in the arc extinguishing stage according to the arc extinguishing welding parameters.

[0067] The automatic welding method and welding system for air-conditioning pipelines of the present invention use stainless steel to replace copper and weld and produce composite pipes through automatic welding technology. During the welding process, relevant parameters are collected in real time and the welding parameters of the automatic welding are adjusted in real time according to the relevant parameters. By collecting relevant parameters of the molten pool, parameters such as current and voltage in real time and dynamically adjusting the welding energy input, the thermal conductivity difference between copper and stainless steel can be effectively overcome, the occurrence probability of defects such as pores and cracks can be reduced, and the reliability of the automatic welding can be improved.

[0068] The air-conditioning pipelines of the present invention use stainless steel to replace copper, which significantly reduces the material cost. Combining real-time parameter adjustment reduces the scrap rate of products, and cooperating with automatic welding control realizes the collaborative optimization of cost reduction and efficiency improvement.

[0069] Specifically, in step S1, the first physical parameters of the copper pipe to be welded and the stainless steel pipe to be welded can be obtained by measuring the dimensions of the copper pipe to be welded, the stainless steel pipe to be welded, and the welding wire. The first environmental parameters can be measured by setting a number of corresponding sensors.

[0070] Specifically, in step S2, the process of determining the arc starting welding parameters according to the first physical parameter and the first environmental parameter includes:

[0071] Step S21, determining the arc starting voltage according to the thickness of the welded joint of the stainless steel pipe and the thickness of the welded joint of the copper pipe, determining the arc starting current according to the wire diameter, determining the arc starting length according to the arc starting voltage and the arc starting current, and determining the initial wire feeding speed according to the arc starting current;

[0072] Step S22, determining the nozzle diameter of the shielding gas according to the arc starting current, the arc starting voltage and the arc starting length;

[0073] Step S23, determining the initial shielding gas flow rate according to the air humidity, the air temperature, the concentration of acidic gas in the air and the nozzle diameter.

[0074] Specifically, in step S21, the process of determining the arc starting current according to the wire diameter includes: determining the distribution coefficient according to the thickness of the welded joint of the stainless steel pipe and the thickness of the welded joint of the copper pipe, and determining the arc starting current according to the current coefficient per unit thickness, the distribution coefficient and the wire diameter.

[0075] In one embodiment, the distribution coefficient is determined according to the thickness of the welded joint of the stainless steel pipe and the thickness of the welded joint of the copper pipe. Let the thickness of the welded joint of the stainless steel pipe be , in mm, and the thickness of the welded joint of the copper pipe be , in mm. Then the distribution coefficient of the stainless steel pipe is , and the distribution coefficient of the copper pipe is , is the current coefficient per unit thickness of stainless steel (30 - 40 A / mm), is the current coefficient per unit thickness of copper (80 - 150 A / mm). Then the arc starting current calculation formula is as follows:

[0076]

[0077] Among them, is the steel pipe correction value, taking 20, is the copper pipe correction value, taking 30. The correction value takes a positive value for thin plates and a negative value for thick plates. For example, if the thickness of the welded joint of the stainless steel pipe is 3 mm and the thickness of the welded joint of the copper pipe is 5 mm, then is 20, is -30, and d is the wire diameter, in mm.

[0078] Specifically, in step S21, the process of determining the arc starting voltage according to the thickness of the welded joint of the stainless steel pipe and the thickness of the welded joint of the copper pipe includes:

[0079] Determine the average thickness of the welded joint based on the thickness of the welded joint of the stainless steel pipe and the thickness of the welded joint of the copper pipe. Determine the welding proportionality coefficient based on the average thickness, and determine the starting arc voltage based on the welding proportionality coefficient and the base voltage.

[0080] In one embodiment, the thickness of the welded joint of the stainless steel pipe is and the thickness of the welded joint of the copper pipe is , then the average thickness of the welded joint is . Preset an average thickness range, and the two endpoint values of the average thickness range are respectively taken as the minimum value and the maximum value of the thickness data of the air-conditioning pipeline with qualified historical welding. Determine the welding proportionality coefficient according to the average thickness of the welded joint and the average thickness range , The value range is 0.05 - 0.15 V / A. Determine the proportionality coefficient according to the position of the average thickness of the welded joint in the average thickness range . For example, if the average thickness of the welded joint is the median of the average thickness range, then the proportionality coefficient takes the median value of the value range 0.05 - 0.15 V / A, which is 0.10 V / A. The base voltage C is the no-load voltage of the automatic welding equipment, then the starting arc voltage is the sum of the base voltage C and the product of the proportionality coefficient and the starting arc current.

[0081] It can be understood that there are differences in the thermal conductivity of stainless steel and copper. When the present invention welds the stainless steel pipe and the copper pipe, based on the average thickness, the starting arc voltage is corrected through the proportionality coefficient, which can dynamically balance the thermal requirements of stainless steel and copper, avoid insufficient penetration on the copper side due to excessive heat dissipation, and prevent intergranular corrosion caused by overheating on the stainless steel side.

[0082] Specifically, in step S21, determine the starting arc length according to the starting arc voltage and the starting arc current.

[0083] In one embodiment, the starting arc length is calculated according to the following formula:

[0084]

[0085] where is the starting arc length, with the unit of mm, is the proportionality constant, with the unit of A / V, and the value range is 0.1 - 0.3, is the starting arc voltage, with the unit of V, is the starting arc current, with the unit of A, is the material current coefficient of stainless steel, taking 1.0, is the material current coefficient of copper, taking 1.8, is the humidity correction coefficient, with a value range of 0.05 to 0.15. A higher value is taken for humidity-sensitive materials. When the welding material is sensitive to humidity (moisture) in the air, the value of the humidity correction coefficient should be selected as the larger value within its value range (0.05 to 0.15) (i.e., close to 0.15), and is the relative humidity of the air.

[0086] Specifically, in step S21, the initial wire feeding speed is determined according to the arc starting current.

[0087] In one embodiment, the initial wire feeding speed is the arc starting current (unit: A) divided by the wire melting coefficient (unit: A·min / m). Among them, the wire melting coefficient is usually 2 to 6 A·min / m, depending on the wire material and diameter. In this embodiment, the wire material is preferably a steel wire with a diameter of 0.001 m, and the wire melting coefficient takes .

[0088] Specifically, after the arc starting voltage and arc starting current in the arc starting stage are determined, the initial welding speed in the arc starting stage can be determined according to the arc starting voltage and arc starting current. Specifically, the initial welding speed in the arc starting stage is calculated according to the following formula:

[0089]

[0090] Among them, is the initial welding speed in the arc starting stage, P is the comprehensive correction coefficient (determined through process tests, typical range ), is the arc starting current, is the arc starting voltage, is the average thermal conductivity of the material, taking the average value of the thermal conductivities of stainless steel and copper. h is the average thickness of the material, in mm, taking the average thickness at the welding joint. The thickness of the welding joint of the stainless steel pipe is , and the thickness of the welding joint of the copper pipe is , then the average thickness of the welding joint is .

[0091] Specifically, in step S22, the process of determining the nozzle diameter of the shielding gas according to the arc starting current, arc starting voltage, and arc starting length includes:

[0092] The arc starting current and arc starting voltage determine the initial heat input during welding. The nozzle diameter determines the coverage range of the shielding gas. The higher the heat input, the larger the coverage range required, and the nozzle diameter needs to be increased. The larger the arc starting length, the smaller the coverage range of the shielding gas required, and thus the nozzle diameter can be reduced. Therefore, the nozzle diameter is positively correlated with the heat input, that is, the product of the arc starting current and arc starting voltage, and negatively correlated with the arc starting length.

[0093] In one embodiment, the nozzle diameter is the product of the arc starting voltage and the arc starting current multiplied by the comprehensive process coefficient and then divided by the arc starting length. The comprehensive process coefficient needs to be calibrated through experiments, and the recommended initial value is 0.02 - 0.05 ).

[0094] Among them, the comprehensive process coefficient can be calibrated through multi-variable orthogonal experiments. Design multiple combinations of arc starting voltage, arc starting current, and arc starting length, such as a 3×3×3 orthogonal experiment table. Fit the average value and confidence interval of the comprehensive process coefficient through a large amount of experimental data to eliminate the single variable error.

[0095] Specifically, in step S23, the process of determining the initial shielding gas flow rate according to the air humidity, air temperature, concentration of acidic gases in the air, and the nozzle diameter includes:

[0096] Determine the basic flow rate of the shielding gas according to the welding speed and the nozzle diameter, determine the humidity correction value, temperature correction value, and acidic gas correction value according to the air humidity, air temperature, and concentration of acidic gases in the air respectively, and determine the initial shielding gas flow rate according to the basic flow rate, humidity correction value, temperature correction value, and acidic gas correction value.

[0097] In one embodiment, the initial shielding gas flow rate Q is as follows:

[0098]

[0099] Among them, is the automatic welding correction coefficient, with the unit of mm, taking 0.8, is the nozzle diameter, with the unit of mm, is the initial welding speed, with the unit of mm / s, is the humidity correction value, is the temperature correction value, is the acidic gas correction value, is the air humidity, is the difference between the air temperature and the standard temperature (25°C), is the concentration of acidic gases.

[0100] More specifically, for the humidity correction value , set the humidity critical threshold. When , start humidity correction, =0.02.

[0101] For the temperature correction value , implement segmented correction. When , take 0.1. When , take 0. When 15°C , Take 0.05.

[0102] For the correction value of acid gas , piecewise correction is implemented. When 5 ppm, take 0.1. When 5 20 ppm, take 0.3. When --, take 0.5.

[0103] It can be understood that the above humidity correction value, temperature correction value, and acid gas correction value are also used to eliminate the dimensions of humidity, temperature, and acid gas concentration.

[0104] The present invention matches the gas flow through environmental parameters and nozzle diameter, can effectively isolate moisture and acid gas in the air, avoid hydrogen embrittlement, nitridation, or sulfide pollution of the molten pool, and avoid waste caused by excessive gas supply during the arc starting stage through the matching of nozzle diameter and flow rate. At the same time, it prevents the protection from failing due to insufficient flow rate. During the welding process, the flow rate of the shielding gas is dynamically adjusted according to the welding speed and the surface temperature of the molten pool, significantly reducing the porosity and surface oxidation.

[0105] Specifically, in step S32, determining the characteristics of the welding molten pool includes:

[0106] Using an infrared thermal imager to photograph the molten pool, respectively identifying the isotherms on the copper tube side and the stainless steel tube side corresponding to the molten pool, taking the isotherm corresponding to the first temperature on the copper tube side as the first boundary of the molten pool, taking the isotherm corresponding to the second temperature on the stainless steel tube side as the second boundary of the molten pool, and determining the surface area of the molten pool according to the first boundary and the second boundary of the molten pool.

[0107] Evenly setting a number of monitoring points between the center of the molten pool and the first boundary and the second boundary of the molten pool and obtaining the temperatures of the monitoring points, and determining the surface temperature of the molten pool according to the temperatures of the monitoring points.

[0108] Specifically, the first temperature is the melting point of the copper tube, and the melting point of copper, about 1083 °C, can be taken. The second temperature is the melting point of the stainless steel tube, and the melting point of stainless steel, about 1450 °C, is taken. The first boundary and the second boundary are the boundaries on both sides of the molten pool. The front and rear boundaries of the molten pool are the third boundary and the fourth boundary respectively. The third boundary is the solidification boundary of the welding wire (using the isotherm corresponding to the third temperature as the third boundary of the molten pool, and the third temperature usually takes the melting point of the welding wire), and the fourth boundary is the current welding position. The area enclosed by the first boundary and the second boundary of the molten pool and the closed area formed by the third boundary and the fourth boundary is determined as the surface of the molten pool. After determining the surface of the molten pool, the specific surface area of the molten pool can be obtained based on machine vision.

[0109] It is understandable that since the two sides of the welding in the present invention are made of different metals and there are differences in their physical properties, therefore, in identifying the size of the molten pool area, corresponding temperature identification boundaries are adopted to distinguish the welding affected area from the molten pool area, so that the range of the molten pool boundary can be accurately obtained, the identification accuracy of the molten pool size is improved, and thus the adjustment accuracy of adjusting the welding parameters based on the molten pool characteristics in the present invention is enhanced.

[0110] When welding dissimilar metals, such as copper and stainless steel in the present application, there is a large difference in the thermal conductivity between copper and stainless steel. The traditional optical method is easily interfered by thermal deformation and it is difficult to uniformly calibrate the molten pool boundary. While the method of dividing temperature thresholds can independently adapt to different material characteristics. The present invention delimits the molten pool boundary through the isotherm corresponding to the melting point, avoiding misjudging the heat affected zone as the molten pool, and can independently calibrate the true melting range on both material sides.

[0111] The accurate calibration of the molten pool boundary in the present invention is the premise for determining whether the interface of dissimilar metals is fully melted. And accurate control of the molten pool surface area can avoid incomplete fusion or excessive penetration. Real-time monitoring of the molten pool surface area and temperature gradient can quantify the thermal state of the molten pool, avoiding brittle phases (coarse grains) or microcracks (deformation or burn-through, the molten pool fails to cover the welding path, resulting in incomplete fusion or discontinuous welds) at the interface caused by uneven temperature. By setting the molten pool boundary through the temperature threshold method, the identification accuracy of the molten pool characteristics in the welding of dissimilar metals is significantly improved, and then the dynamic optimization of welding parameters is realized, improving the welding quality.

[0112] Specifically, the average value of the temperatures of several monitoring points is used as the molten pool surface temperature data.

[0113] Specifically, the process of determining whether to adjust the welding parameters in real time based on the molten pool parameters corresponding to the welding molten pool characteristics includes:

[0114] Determining the adjustment of the welding current and / or welding speed according to the comparison result between the molten pool surface temperature and the preset temperature range;

[0115] Determining the adjustment of the welding voltage and / or arc length according to the comparison result between the molten pool surface area and the preset area range.

[0116] Please refer to Figure 2 , in one embodiment, determining the adjustment of the welding current and / or welding speed according to the molten pool surface temperature and the preset temperature range includes:

[0117] If the molten pool surface temperature is greater than the maximum value of the preset temperature range, then on the basis of the existing welding current, the welding current is reduced by 5% - 10% each time and / or on the basis of the existing welding speed, the welding speed is increased by 10 - 20 cm / min each time until the molten pool surface temperature drops within the preset temperature range;

[0118] If the surface temperature of the molten pool is less than the minimum value of the preset temperature range, the welding current is increased by 5% - 10% each time on the basis of the existing welding current and / or the welding speed is decreased by 10 - 20 cm / min each time on the basis of the existing welding speed until the surface temperature of the molten pool rises within the preset temperature range.

[0119] If the surface temperature of the molten pool is within the preset temperature range, the current welding current and welding speed are maintained.

[0120] As an implementation manner, the preset temperature range is determined according to the average temperature of the molten pool during the welding process without welding defects such as cracks and pores in the historical automatic welding of air-conditioning pipelines. During the welding process of each copper pipe to be welded and stainless steel pipe to be welded, the second physical parameters of the molten pool include: the surface temperature of the molten pool and the surface area of the molten pool, which are both detected, recorded and saved in real time. After the first N automatic weldings are completed, the finished products are inspected. For the n qualified finished products (n ≤ N) (without welding defects such as cracks and pores), the average value of the surface temperature of the molten pool during the welding process of the n finished products is taken to form a temperature set. The maximum value in the temperature set is taken as the upper limit value of the preset temperature range, and the minimum value in the set is taken as the lower limit value of the preset temperature range. According to this preset temperature range, the (N + 1)-th automatic welding is carried out. After the welding is completed, if the finished product passes the quality inspection (without welding defects such as cracks and pores), the average value of the surface temperature of the molten pool during this welding process is added to the above temperature set for updating, and then the preset temperature range is determined again.

[0121] The present invention adjusts the welding current and / or welding speed based on the surface temperature of the molten pool. The surface temperature of the molten pool directly reflects the heat input. When it is detected that the temperature exceeds the preset range, it indicates that the temperature is too high, and the welding current and / or welding speed are automatically adjusted to reduce the heat input per unit length and avoid burn-through or grain coarsening. When the temperature is too low, reverse adjustment is carried out to ensure that the penetration meets the standard.

[0122] It can be understood that whether to adjust the welding current and / or welding speed is determined according to the comparison result between the surface temperature of the molten pool and the preset temperature range. Adjusting the welding current and / or welding speed can both achieve the adjustment and control of the surface temperature of the molten pool. One welding parameter of the welding current and welding speed can be adjusted only, or both the welding current and welding speed can be adjusted.

[0123] In one embodiment, the adjustment of the welding voltage and / or arc length according to the surface area of the molten pool and the preset area range includes:

[0124] If the surface area of the molten pool is greater than the maximum value of the preset area range, the welding voltage is decreased in steps of 2 - 3 V on the basis of the existing welding voltage, and / or the arc length is shortened in steps of 0.1 - 0.2 mm until the surface area of the molten pool drops within the preset area range;

[0125] If the surface area of the molten pool is less than the minimum value of the preset area range, the welding voltage is increased in steps of 2-3 V on the basis of the existing welding voltage, and / or the arc length is extended in steps of 0.1-0.2 mm until the surface area of the molten pool rises within the preset area range.

[0126] If the surface area of the molten pool is within the preset area range, the current welding voltage and arc length are maintained.

[0127] As an implementation method, the preset area range is determined according to the average surface area of the molten pool during the welding process without welding defects such as cracks and pores in the historical automatic welding process of the air-conditioning pipeline. During the welding process of the copper pipe to be welded and the stainless-steel pipe to be welded each time, the second physical parameters of the molten pool include: the surface temperature of the molten pool and the surface area of the molten pool are both detected, recorded and saved in real time. After the first N automatic weldings are completed, the finished products are inspected. For the n qualified finished products (n≤N) (without welding defects such as cracks and pores), the average value of the surface areas of the molten pool during the welding process of the n finished products is taken to form a surface area set. The maximum value in the surface area set is taken as the upper limit value of the preset area range, and the minimum value in the set is taken as the lower limit value of the preset area range. According to this preset area range, the (N + 1)-th automatic welding is carried out. After the welding is completed, if the finished product passes the quality inspection (without welding defects such as cracks and pores), the average value of the surface area of the molten pool during this welding process is added to the above surface area set for updating, and then the preset area range is determined again.

[0128] Based on the adjustment of the welding voltage and / or the arc length according to the surface area of the molten pool, the surface area of the molten pool reflects the state of the arc energy distribution. If the surface area is too large, it indicates that the arc is divergent. Reducing the voltage or shortening the arc can increase the arc energy density and inhibit the excessive spreading of the molten pool. If the surface area is too small, the reverse adjustment is made to avoid the lack of fusion defect.

[0129] It can be understood that determining whether to adjust the welding voltage and / or the arc length according to the comparison result between the surface area of the molten pool and the preset area range, and adjusting the welding voltage and / or the arc length can both realize the adjustment and control of the surface temperature of the molten pool. One of the welding parameters of the welding voltage and the arc length can be adjusted, or both the welding voltage and the arc length can be adjusted.

[0130] The present invention also provides another implementation method. The second physical parameters of the molten pool include: the molten pool temperature (the surface temperature of the molten pool), the molten pool length (determined according to the third boundary and the fourth boundary, and taking the average value of the distance between the third boundary and the fourth boundary), the molten pool width (determined according to the first boundary and the second boundary, and taking the average value of the distance between the first boundary and the second boundary), and the molten pool depth (the maximum value of the molten pool thickness);

[0131] The determination of the adjustment strategy according to the second physical parameters includes:

[0132] Determine the adjustment of the welding current and / or welding speed according to the molten pool temperature and the preset temperature range;

[0133] Determine the adjustment of the welding speed and / or welding current according to the molten pool length and the preset length range;

[0134] Determine the adjustment of the welding voltage and / or arc length according to the molten pool width and the preset width range;

[0135] Determine the adjustment of the welding current and / or welding speed according to the molten pool depth and the preset depth range.

[0136] It can be understood that for the second physical parameters, namely the molten pool temperature, molten pool length, molten pool width, and molten pool depth, the molten pool temperature can be directly measured or indirectly measured by an infrared pyrometer, thermal imager, spectrometer, etc. For the molten pool geometric parameters, after using the infrared thermal imager to photograph the molten pool and determining the first boundary, second boundary, third boundary, and fourth boundary, the molten pool length and molten pool width can be determined, or they can also be directly measured or indirectly measured by means such as the cooperation of a high-speed camera and a filter system, a coaxial vision system, and ultrasonic detection.

[0137] The molten pool temperature is a key parameter in the welding process, directly affecting the weld formation, metallurgical reaction, and welding quality. The molten pool temperature is approximately linearly positively correlated with the welding current and inversely proportional to the welding speed. Therefore, the present invention monitors the molten pool temperature in real time during the welding process and adjusts the molten pool temperature in a timely manner by controlling the welding current and welding speed.

[0138] Please refer to Figure 4 , in one embodiment, determining the adjustment of the welding current and / or welding speed according to the molten pool temperature and the preset temperature range includes:

[0139] If the molten pool temperature is greater than the upper limit value of the preset temperature range, then each time the welding current is reduced by 5% - 10% based on the existing welding current and / or the welding speed is increased by 10 - 20 cm / min each time based on the existing welding speed until the molten pool temperature drops within the preset temperature range;

[0140] If the molten pool temperature is less than the lower limit value of the preset temperature range, then each time the welding current is increased by 5% - 10% based on the existing welding current and / or the welding speed is reduced by 10 - 20 cm / min each time based on the existing welding speed until the molten pool temperature rises within the preset temperature range.

[0141] As an implementation manner, the preset temperature range is determined according to the average temperature of the molten pool during the welding process in the historical automatic welding of the air-conditioning pipeline without welding defects such as cracks and pores. During the welding process of the copper pipe to be welded and the stainless-steel pipe to be welded each time, the second physical parameters of the molten pool include: the molten-pool temperature, the molten-pool length, the molten-pool width, and the molten-pool depth, which are all detected, recorded, and saved in real time. After the first N automatic weldings are completed, the finished products are inspected. For the n qualified finished products (n ≤ N) (without welding defects such as cracks and pores), the average value of the molten-pool temperatures during the welding process of the n finished products is taken to form a temperature set. The maximum value in the temperature set is taken as the upper limit value of the preset temperature range, and the minimum value in the set is taken as the lower limit value of the preset temperature range. According to this preset temperature range, the (N + 1)-th automatic welding is carried out. After the welding is completed, if the finished product is qualified in quality inspection (without welding defects such as cracks and pores), the average value of the molten-pool temperature during this welding process is added to the above temperature set for updating, and then the preset temperature range is determined again.

[0142] The molten pool extends beyond the range of the weld groove, resulting in an enlarged heat-affected zone, which may cause deformation or burn-through (for thin pipes). The molten pool fails to cover the welding path, resulting in lack of fusion or discontinuous welds. The molten-pool length is directly related to the welding speed. The faster the speed, the shorter the molten pool; conversely, the longer the molten pool. Therefore, the present invention monitors the molten-pool length during the welding process in real time and adjusts the molten-pool length in a timely manner by controlling the welding speed.

[0143] Please refer to Figure 5 , in an embodiment, determining the adjustment of the welding speed and / or the welding current according to the molten-pool length and the preset length range includes:

[0144] If the molten-pool length is greater than the upper limit value of the preset length range, the welding speed is increased by an increment of 5 - 10 cm / min each time on the basis of the existing welding speed until the molten-pool length drops within the preset length range. During the process of increasing the welding speed, if the molten-pool depth is less than the lower limit value of the preset depth range, the welding current is increased by 5 - 10 A for every 10 cm / min increase in the welding speed until the molten-pool depth rises within the preset depth range;

[0145] If the molten-pool length is less than the lower limit value of the preset length range, the welding speed is decreased by an increment of 5 - 10 cm / min each time on the basis of the existing welding speed until the molten-pool length rises within the preset length range. During the process of decreasing the welding speed, if the molten-pool depth is greater than the upper limit value of the preset depth range, the welding current is decreased by 5 - 10 A for every 10 cm / min decrease in the welding speed until the molten-pool depth drops within the preset depth range.

[0146] As an implementation manner, the preset length interval is determined according to the average length of the molten pool during the welding process without welding defects such as cracks and pores in the historical automatic welding process of the air-conditioning pipeline. During the welding process of the copper pipe and the stainless steel pipe to be welded each time, the second physical parameters of the molten pool include: the molten pool temperature, the molten pool length, the molten pool width, and the molten pool depth are all detected, recorded, and saved in real time. After the first N automatic weldings are completed, the finished products are inspected. For the n qualified finished products (n ≤ N) (without welding defects such as cracks and pores), the average value of the molten pool lengths during the welding processes of the n finished products is taken to form a length set. The maximum value in the length set is taken as the upper limit value of the preset length interval, and the minimum value in the set is taken as the lower limit value of the preset length interval. According to this preset length interval, the (N + 1)-th automatic welding is carried out. After the welding is completed, if the finished product passes the quality inspection (without welding defects such as cracks and pores), the average value of the molten pool length during this welding process is added to the above length set for updating, and then the preset length interval is re-determined.

[0147] If the molten pool width is too wide, it indicates that too much heat diffuses laterally, the weld surface is sunken, and the grains in the heat-affected zone are coarsened. If it is too narrow, there will be poor fusion, the weld formation is narrow and high, and it is easy to produce undercut or slag inclusion. The molten pool width is determined by the arc energy distribution and is directly affected by the welding voltage and the arc length. Therefore, the present invention monitors the molten pool width during the welding process in real time and adjusts the molten pool width by controlling the welding voltage and the arc length.

[0148] Please refer to Figure 6 , in an embodiment, the determination of the welding voltage and / or the adjustment of the arc length according to the molten pool width and the preset width interval includes:

[0149] If the molten pool width is greater than the maximum value of the preset width interval, the welding voltage is reduced in steps of 2 - 3V based on the existing welding voltage, and / or the arc length is shortened in steps of 0.1 - 0.2mm until the molten pool width drops within the preset width interval;

[0150] If the molten pool width is less than the minimum value of the preset width interval, the welding voltage is increased in steps of 2 - 3V based on the existing welding voltage, and / or the arc length is extended in steps of 0.1 - 0.2mm until the molten pool width rises within the preset width interval.

[0151] As an implementation manner, the preset width interval is determined according to the diameter of the welding wire. The lower limit value of the preset width interval is × the diameter of the welding wire, and the upper limit value of the preset width interval is × the diameter of the welding wire.

[0152] In an embodiment, = 2, = 3.

[0153] The molten pool depth is an important indicator of welding quality, directly affecting the penetration, mechanical properties, and defect control of the weld seam. The molten pool depth is approximately linearly positively correlated with the current and inversely proportional to the welding speed. Therefore, the present invention monitors the molten pool depth during the welding process in real time and adjusts the molten pool width in a timely manner by controlling the welding current and welding speed.

[0154] Please refer to Figure 7 , in one embodiment, determining the adjustment of the welding current and / or welding speed according to the molten pool depth and a preset depth range includes:

[0155] If the molten pool depth is greater than the maximum value of the preset depth range, the welding current is reduced in steps of 10 - 20 A based on the existing welding current, and / or the welding speed is increased by 10% - 20% until the molten pool depth drops within the preset depth range;

[0156] If the molten pool depth is less than the minimum value of the preset depth range, the welding current is increased in steps of 10 - 20 A based on the existing welding current, and / or the welding speed is reduced by 10% - 20% until the molten pool depth rises within the preset depth range.

[0157] As an implementation method, the preset depth range is determined according to the average depth of the molten pool during the welding process of the historical air-conditioning pipeline automatic welding without welding defects such as cracks and pores. During the welding process of each copper pipe to be welded and stainless steel pipe to be welded, the second physical parameters of the molten pool, including the molten pool temperature, molten pool length, molten pool width, and molten pool depth, are detected, recorded, and saved in real time. After the first N automatic weldings are completed, the finished products are inspected. For the n qualified finished products (n ≤ N) (without welding defects such as cracks and pores), the average value of the molten pool depth during the welding process of the n finished products is taken to form a depth set. The maximum value in the depth set is taken as the upper limit value of the preset depth range, and the minimum value in the set is taken as the lower limit value of the preset depth range. According to this preset depth range, the (N + 1)-th automatic welding is carried out. After the welding is completed, if the finished product passes the quality inspection (without welding defects such as cracks and pores), the average value of the molten pool depth during this welding process is added to the above depth set for updating, and then the preset depth range is re-determined.

[0158] Specifically, it further includes: adjusting the wire feeding speed according to the welding speed and welding current during the self-adjustment stage.

[0159] In one embodiment, adjusting the wire feeding speed according to the welding speed and welding current includes: adjusting the wire feeding speed according to the collaborative adjustment formula of the welding speed and welding current, and the formula is as follows:

[0160]

[0161] Among them, is the wire feeding speed, is the welding current, with the unit of A, is the wire melting coefficient, is the cross-sectional area of the weld seam, with the unit of , is the wire diameter, with the unit of mm, is the welding speed, with the unit of mm / s, is the material density, is the deposition efficiency. For steel wires, , , with the unit of g / min, .

[0162] As an implementation manner, the data parameters involved in the above wire feeding speed calculation formula of the present invention are all converted through data format conversion to eliminate the dimension difference. For example, different dimension data are converted into data under the same dimension through standardization.

[0163] Specifically, it further includes: dynamically adjusting the current shielding gas flow according to the welding speed, the molten pool surface temperature, and the initial shielding gas flow during the self-adjustment stage.

[0164] In one embodiment, dynamically adjusting the current shielding gas flow according to the welding speed, the molten pool surface temperature, and the initial shielding gas flow includes: integrating the welding speed and the temperature effect, constructing a dynamic adjustment formula, and dynamically adjusting the shielding gas flow according to the dynamic adjustment formula. The dynamic adjustment formula is as follows:

[0165]

[0166] Among them, is the shielding gas flow, with the unit of L / min, Q is the initial shielding gas flow, with the unit of L / min, is the reference welding speed, with the range of 300 mm / min to 1000 mm / min, is the welding speed, with the unit of mm / min, is the molten pool surface temperature, with the unit of °C, is the standard temperature (taking 50% of the higher melting point of the welding material, that is, 50% of the melting point of stainless steel), with the unit of °C, is the speed sensitivity coefficient, taking 0.5 to 1.5, is the temperature sensitivity coefficient, taking 0.2 to 0.5.

[0167] Specifically, the process of determining the arc extinguishing welding parameters according to the welding parameters in the self-adjustment stage includes:

[0168] Determine the arc-extinguishing current according to the welding current in the self-adjustment stage, and the arc-extinguishing current is positively correlated with the welding current in the self-adjustment stage. Determine the arc-extinguishing voltage according to the welding voltage in the self-adjustment stage, and the arc-extinguishing voltage is positively correlated with the welding voltage in the self-adjustment stage.

[0169] In one embodiment, the arc-extinguishing current = the average value of the welding current in the adjustment stage , and the arc-extinguishing voltage = the average value of the welding voltage in the adjustment stage .

[0170] As an implementation method, the division methods of the arc-starting stage, the self-adjustment stage, and the arc-extinguishing stage are as follows: the range from 0.1 s to 0.5 s after the start of welding is the arc-starting stage, the arc-extinguishing stage is entered when the distance from the end of the weld seam is 2 mm to 5 mm, and the self-adjustment stage is between the arc-starting stage and the arc-extinguishing stage.

[0171] Please refer to Figure 8 , on the other hand, the present invention also provides an automatic welding system for air-conditioning pipelines, including:

[0172] A data acquisition module for acquiring the first physical parameters and the first environmental parameters of the copper pipe and the stainless steel pipe to be welded, and for acquiring the second physical parameters of the molten pool in real time;

[0173] An arc-starting welding parameter determination module, which is connected to the data acquisition module and is used to determine the arc-starting welding parameters according to the first physical parameters and the first environmental parameters;

[0174] A self-adjustment strategy analysis module, which is connected to the data acquisition module and is used to determine the characteristics of the welding molten pool according to the second physical parameters, and to judge whether it is necessary to adjust the welding parameters in real time based on the molten pool parameters corresponding to the characteristics of the welding molten pool;

[0175] An arc-extinguishing welding parameter determination module, which is connected to the data acquisition module and is used to determine the arc-extinguishing welding parameters according to the welding parameters in the self-adjustment stage;

[0176] An automatic welding device, which is respectively connected to the arc-starting welding parameter determination module, the self-adjustment strategy analysis module, and the arc-extinguishing welding parameter determination module, and is used to weld the copper pipe to be welded and the stainless steel pipe to be welded according to the welding parameters in the arc-starting stage, the self-adjustment stage, and the arc-extinguishing stage.

[0177] It should be understood that since the setting of each of the above modules is only for explaining the functional units of the system of the present disclosure, the physical devices corresponding to these modules can be the processor itself, or a part of the software in the processor, a part of the hardware, or a part of the combination of software and hardware. Therefore, the number of each module in the figure is only illustrative.

[0178] The various embodiments of the systems and techniques described above in this document can be implemented in digital electronic circuitry, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-chips (SOCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special-purpose or general-purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit the data and instructions to the storage system, the at least one input device, and the at least one output device.

[0179] To solve the above technical problems, an embodiment of the present invention further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps of a method for automatic welding of air-conditioning pipelines as described above.

[0180] As Figure 9 shown, the computer / electronic device includes a memory, a processor, and a network interface that are communicatively connected to each other through a system bus. It should be noted that only a computer device with components such as a memory, a processor, a network interface, and an operating system is shown in the figure. However, it should be understood that it is not required to implement all the shown components, and more or fewer components can be alternatively implemented. Among them, those skilled in the art of this technology can understand that the computer / electronic device here is a device that can automatically perform numerical calculations and / or information processing according to pre-set or stored instructions, and its hardware includes but is not limited to microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), embedded devices, etc.

[0181] The computer / electronic device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The computer / electronic device can interact with the user through means such as a keyboard, a mouse, a remote control, a touchpad, or a voice control device.

[0182] The memory can be one or more, and at least includes one type of readable storage medium, which includes flash memory, hard disk, multimedia card, card-type memory (such as SD or DX memory, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disc, etc. In some embodiments, the memory can be an internal storage unit of the computer device, such as the hard disk or memory of the computer device. In other embodiments, the memory can also be an external storage device of the computer device, such as the plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, FlashCard, etc. equipped on the computer device. Of course, the memory can also include both the internal storage unit and the external storage device of the computer device. In this embodiment, the memory is generally used to store the operating system and various application software installed in the computer device, such as the program code for an automatic welding method of air-conditioning pipelines. In addition, the memory can also be used to temporarily store various types of data that have been output or will be output.

[0183] In some embodiments, the processor can be a central processing unit (CPU), controller, microcontroller, microprocessor or other data processing chip. The processor is generally used to control the overall operation of the computer device. In this embodiment, the processor is used to run the program code stored in the memory or process data, such as running the program code for an automatic welding method of air-conditioning pipelines.

[0184] The network interface can include a wireless network interface and / or a wired network interface, which is generally used to establish a communication connection between the computer device and other electronic devices.

[0185] The present invention also provides another implementation manner, that is, to provide a 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 an automatic welding method for air-conditioning pipelines as described above.

[0186] So far, the technical solution of the present invention has been described in combination 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 all fall within the protection scope of the present invention.

[0187] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention; for those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An automatic welding method for air-conditioning pipelines, characterized in that, Including: Obtain the first physical parameters and the first environmental parameters of the copper pipe to be welded and the stainless steel pipe to be welded. Among them, the first physical parameters include the thickness of the welded part of the stainless steel pipe, the thickness of the welded part of the copper pipe, and the wire diameter. The first environmental parameters include air humidity, air temperature, and the concentration of acidic gases in the air; Determine the arc-starting welding parameters according to the first physical parameters and the first environmental parameters, and perform welding in the arc-starting stage according to the arc-starting welding parameters. Among them, determine the arc-starting voltage according to the thickness of the welded part of the stainless steel pipe and the thickness of the welded part of the copper pipe, determine the arc-starting current according to the wire diameter, determine the arc-starting length according to the arc-starting voltage and the arc-starting current, and determine the initial wire feeding speed according to the arc-starting current; Determine the nozzle diameter of the shielding gas according to the arc-starting current, arc-starting voltage, and arc-starting length; Determine the initial shielding gas flow rate according to air humidity, air temperature, the concentration of acidic gases in the air, and the nozzle diameter; When the welding in the arc-starting stage is completed, perform welding in the self-adjustment stage, Obtain the second physical parameters of the molten pool in real time. Among them, the second physical parameters include the surface temperature of each position of the molten pool; Identify the isotherm on the copper pipe side and the isotherm on the stainless steel pipe side corresponding to the molten pool respectively. Take the isotherm corresponding to the first temperature on the copper pipe side as the first boundary of the molten pool, and take the isotherm corresponding to the second temperature on the stainless steel pipe side as the second boundary of the molten pool. Determine the surface area of the molten pool according to the first boundary and the second boundary of the molten pool; Uniformly set a number of monitoring points between the center of the molten pool and the first boundary and the second boundary of the molten pool, and obtain the temperatures of the monitoring points. Determine the surface temperature of the molten pool according to the temperatures of the monitoring points; Judge whether to adjust the welding parameters in real time based on the surface area and surface temperature of the molten pool, and perform welding in the self-adjustment stage according to the welding parameters adjusted in real time; When the welding in the self-adjustment stage is completed, enter the arc-ending stage welding. Determine the arc-ending welding parameters according to the welding parameters in the self-adjustment stage, and perform welding in the arc-ending stage according to the arc-ending welding parameters.

2. The automatic welding method for an air-conditioning pipeline according to claim 1, wherein The process of determining the arc-starting voltage according to the thickness of the welded part of the stainless steel pipe and the thickness of the welded part of the copper pipe includes: Determine the average thickness of the welded part according to the thickness of the welded part of the stainless steel pipe and the thickness of the welded part of the copper pipe; Determine the welding proportionality coefficient according to the average thickness; Determine the arc-starting voltage according to the welding proportionality coefficient and the base voltage.

3. The automatic welding method for air-conditioning pipelines according to claim 1, wherein The process of determining the arc-starting current according to the wire diameter includes: Determine the distribution coefficient according to the thickness of the welded part of the stainless steel pipe and the thickness of the welded part of the copper pipe, and determine the arc-starting current according to the current coefficient per unit thickness, the distribution coefficient, and the wire diameter.

4. The automatic welding method for an air-conditioning pipeline according to claim 1, characterized in that The process of determining the initial shielding gas flow rate according to air humidity, air temperature, and the concentration of acidic gases in the air includes: Determine the base flow rate of the shielding gas according to the welding speed and the nozzle diameter. Determine the humidity correction value, temperature correction value, and acidic gas correction value according to air humidity, air temperature, and the concentration of acidic gases in the air respectively. Determine the initial shielding gas flow rate according to the base flow rate, humidity correction value, temperature correction value, and acidic gas correction value.

5. The automatic welding method for an air-conditioning pipeline according to claim 1, characterized in that, The process of judging whether to adjust the welding parameters in real time based on the surface area and surface temperature of the molten pool includes: Determine whether to adjust the welding current and / or welding speed according to the comparison result between the molten pool surface temperature and the preset temperature range; Determine whether to adjust the welding voltage and / or arc length according to the comparison result between the molten pool surface area and the preset area range.

6. The automatic welding method for air-conditioning pipelines according to claim 1, characterized in that It further includes: During the self-adjustment stage, adjust the wire feeding speed according to the welding speed and welding current, and dynamically adjust the current shielding gas flow according to the welding speed, the molten pool surface temperature, and the initial shielding gas flow.

7. The automatic welding method for air-conditioning pipelines according to claim 1, characterized in that, The process of determining the arc-extinguishing welding parameters according to the welding parameters in the self-adjustment stage includes: Determine the arc-extinguishing current according to the welding current in the self-adjustment stage, and the arc-extinguishing current is positively correlated with the welding current in the self-adjustment stage; determine the arc-extinguishing voltage according to the welding voltage in the self-adjustment stage, and the arc-extinguishing voltage is positively correlated with the welding voltage in the self-adjustment stage.

8. An automatic welding system for air-conditioning pipelines, which is applied to the automatic welding method for air-conditioning pipelines according to any one of claims 1-7, is characterized in that, It includes: A data acquisition module for acquiring the first physical parameters and the first environmental parameters of the copper pipe and the stainless steel pipe to be welded, and for acquiring the second physical parameters of the molten pool in real time; An arc-starting welding parameter determination module connected to the data acquisition module for determining the arc-starting welding parameters according to the first physical parameters and the first environmental parameters; A self-adjustment strategy analysis module connected to the data acquisition module for determining the characteristics of the welding molten pool according to the second physical parameters, and for determining whether to adjust the welding parameters in real time based on the molten pool parameters corresponding to the molten pool surface area and the molten pool surface temperature; An arc-extinguishing welding parameter determination module connected to the data acquisition module for determining the arc-extinguishing welding parameters according to the welding parameters in the self-adjustment stage; An automatic welding device respectively connected to the arc-starting welding parameter determination module, the self-adjustment strategy analysis module, and the arc-extinguishing welding parameter determination module for welding the copper pipe and the stainless steel pipe to be welded according to the welding parameters in the arc-starting stage, the self-adjustment stage, and the arc-extinguishing stage.

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