Alternating current arc electrode tip heat production measurement device and method considering evaporation phase change

Abstract

The present application relates to the measuring device and method of the heat production of the end of the alternating current arc electrode considering the evaporation phase change, belongs to the technical field of arc heat processing and arc physical property measurement. Including: the power supply is connected with the base plate and the welding torch respectively, the base plate adopts the metal block with the center through hole, the inner cavity of the base plate is circularly connected with the cooling water tank, the water inlet of the base plate is provided with the first thermocouple, the water outlet of the base plate is provided with the second thermocouple, the welding torch is correspondingly arranged above the center through hole of the base plate, the calorimeter is arranged below the base plate, and the calorimeter is placed on the balance. The present application records the droplet mass by the balance, compares the mass transfer quality of the wire feeding, obtains the metal evaporation amount, and solves the electrode heat production consumed in the arc heat processing process according to the electrode heat production, which cannot be ignored in the electrode heat production, the evaluation measurement result is reliable, and the measurement precision is improved.

Description

Technical Field

[0001] This invention relates to a device and method for measuring heat generation at the electrode tip, belonging to the technical field of electric arc heat processing and electric arc physical property measurement. Background Technology

[0002] An electric arc is a gas discharge phenomenon that occurs when electricity is applied between electrodes; it is also a form of plasma. Because the discharge process generates a large amount of heat, electric arcs are often used as a heat source for the thermal processing of metallic materials, such as in arc welding and arc additive manufacturing. Alternating current (AC) arcs, due to their unique "cathode cleaning" effect, are widely used for the thermal processing of metals such as aluminum alloys. Therefore, the physical characteristics of AC arcs, such as their temperature field, flow field, magnetic field, and current density distribution, have attracted considerable attention from researchers both domestically and internationally. The heat generated at the tip of the arc electrode determines the thermal state of the heating wire and the workpiece, and is an important reference indicator in the design of arc thermal processing technologies.

[0003] The high brightness and wide spectral distribution of electric arcs hinder the application of visual monitoring in measuring the physical properties of electric arcs. Therefore, research on the physical properties of electric arcs mainly relies on numerical simulation. Numerical simulation, based on existing and mature physical and mathematical formulas, can accurately calculate some physical properties of the electric arc, such as current density, arc temperature, and internal arc flow. Existing research shows that the heat generation at the electrode tip is related to the proportion of electron and ion currents in the current density. Current density equals the sum of electron and ion currents; their heat generation mechanisms on the electrode differ, leading to significant differences in heat generation at the electrode tip under different polarities of AC arcs. Patent application CN106644177B, entitled "A Method for Measuring the Heat Output of AC Welding Arcs," employs a diode-split anode design. When the arc polarity changes, the workpiece end switches, which can easily cause arc interruption and can only be used for measuring arc heat transfer at different stages (positive and negative polarities) at the workpiece end of a non-consumable electrode AC arc. Currently, the electron flow ratio required for calculating heat generation at the electrode tip of an AC arc relies on assumptions and lacks experimental research. This is mainly because there is no practical and effective device or method for measuring heat generation at the electrode tip.

[0004] Therefore, there is an urgent need to propose a device and method for measuring heat generation at the end of an AC arc electrode that takes into account evaporation phase change, in order to solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the aforementioned problems, an alternating current arc electrode tip heat generation measurement device and method considering evaporation phase change are provided. A brief overview of the invention is given below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0006] The technical solution of the present invention: A heat measurement device for the end of an AC arc electrode considering evaporation phase change includes: a power supply connected to a substrate and a welding torch respectively; the substrate is a metal block with a central through hole; the inner cavity of the substrate is circulated with a cooling water tank; a first thermocouple is installed at the water inlet of the substrate; a second thermocouple is installed at the water outlet of the substrate; a welding torch is installed above the central through hole of the substrate; a calorimeter is installed below the substrate; and the calorimeter is placed on a balance.

[0007] Preferably, the metal block is a copper block.

[0008] Preferably, the calorimeter includes: a layer of insulating quartz wool wrapped around the outside of the temperature-sensing copper block, and a third thermocouple for the temperature-sensing copper block.

[0009] Preferably, it also includes a thermocouple acquisition card and a PC terminal, with the first thermocouple, the second thermocouple, and the third thermocouple connected to the PC terminal via the thermocouple acquisition card.

[0010] Preferably, the method using the aforementioned AC arc substrate end heat generation measurement device considering evaporation phase change includes the following steps: Step 1: Circulate water into the inner cavity of the substrate and record the temperatures of the first thermocouple and the second thermocouple; Step 2: Place a baffle above the calorimeter; Step 3: The welding torch is ignited, an arc is established between the welding torch and the substrate, and molten droplets are generated; the arc heats the water-cooled copper block, and the molten droplets fall from the central through hole; Step 4: Set the arc ignition time as follows Δt (s), and wait for the inlet and outlet water temperatures of the substrate to stabilize; Step 5: Calculate the heat transfer of the electric arc to the substrate using the temperature difference between the inlet and outlet water at the steady-state moment; Step 6: Apply a constant magnetic field below the substrate to deflect the arc tail flame and separate it from the falling trajectory of the molten droplet; Step 7: Record the mass of the solid calorimeter before the baffle is removed. m 1; Step 8: Remove the baffle to allow the measuring copper block to collect the falling molten droplets, then extinguish the arc; record the mass of the solid calorimeter. m 2; and calculate the mass of the collected molten droplets. m 2 -m 1; Step 9: Record the wire feeding speed v w Calculate the amount of metal evaporated per unit time. m s ; Step 10: Cover the surface of the solid copper block with quartz wool to reduce heat loss from the molten droplets; Step 11: When the temperature of the third thermocouple stabilizes, record the temperature rise of the copper block.

[0011] Preferably, in step one, the distance between the lower end of the welding torch nozzle and the upper surface of the substrate is 10-12mm, and the sampling rate of the data acquisition card is 2-10. In step two, the distance between the baffle and the upper surface of the calorimeter is 20-25mm; In step seven, the distance between the upper end of the calorimeter and the bottom of the substrate is 120-130 mm; In step eight, the droplet collection time is 20-22 seconds.

[0012] Preferred method: In step nine, the amount of metal evaporated per unit time is calculated according to formula (1). m s ; (1) in: R w The diameter of the wire. ρ It is the density of metallic materials; t It is the time for collecting molten droplets; In step eleven, based on the average temperature change curve Temp ave Record the temperature rise of the copper block ΔTemp ave ; (2).

[0013] Preferred options also include: Repeat steps one through eleven above three times or more to create error bars and enhance the reliability of the data. Adjust the AC arc duty cycle and repeat steps one through twelve to obtain the unit substrate heat, droplet heat and metal evaporation rate under different duty cycles.

[0014] Preferred method: By accumulating the heat generation power at different stages, rapidly changing physical quantities that cannot be directly measured are transformed into macroscopically measurable physical quantities, and the system of simultaneous equations is solved. The formula for calculating the thermal properties of the substrate is shown in (3): (3) The formula for calculating heat generation at the end of the wire is shown in (4): (4) The positive polarity stage is defined as the stage where the wire is connected to the positive electrode; at this time, the heat generation power at the wire end is ( P w ) EP The heat generation power at the substrate end is ( P b ) EP The reverse polarity stage is the stage where the wire is connected to the negative electrode; at this time, the heat generation power at the wire end is (P w ) EN The heat generation power at the substrate end is ( P b ) EN The alternating current arc period is T The positive half-cycle is T EP The negative half-cycle is T EN The droplet collection time is t , c wat The specific heat capacity of cooling water, Q wat For cooling water flow rate, H m The latent heat of molten wire, c cop The specific heat capacity of the solid copper block. m cop The mass of the solid copper block; the two unknowns in formulas (3) and (4) are used to solve the heat generation of the electrode under different polarities of the AC arc by solving the simultaneous equations based on the results of multiple sets of experiments under different duty cycles, and the reliability of the measurement results is analyzed.

[0015] Preferred materials: aluminum, magnesium, and copper wires are used.

[0016] The present invention has the following beneficial effects: 1. The first thermocouple and the second thermocouple of the present invention measure the dynamic evolution of water temperature and wait for the stabilization moment to record the temperature difference, thereby avoiding measurement errors caused by the thermal inertia of water and improving measurement accuracy.

[0017] 2. This invention uses a balance to record the mass of the molten droplet and compares it with the mass transfer mass of the wire feeding to obtain the metal evaporation amount. Based on this, the electrode heat generated by evaporation during the electric arc heat treatment process can be calculated, which is not negligible in electrode heat generation.

[0018] 3. This invention addresses the difference in heat generation at different stages of an alternating electric arc by accumulating the heat generation power at different stages, transforming a rapidly changing physical quantity that cannot be directly measured into a macroscopically measurable physical quantity, solving a system of simultaneous equations, and conducting more than two sets of experiments to solve for two variables, thereby evaluating the reliability of the measurement results. Attached Figure Description

[0019] Figure 1 This is a system diagram of an AC arc electrode tip heat generation measurement device considering evaporation phase change; Figure 2 This is a flowchart of a method for measuring heat generation at the tip of an AC arc electrode that considers evaporation phase change. Figure 3 This is a graph showing the temperature evolution of the inlet and outlet water of the water-cooled copper block. Figure 4 This is a graph showing the average temperature evolution of a solid copper block. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0021] Specific implementation method one: Combining Figure 1 This embodiment describes a heat generation measurement device at the end of an AC arc substrate considering evaporation phase change. It includes a welding torch 1, a power supply 2, and a substrate 3. The positive and negative poles of the power supply 2 are electrically connected to the substrate 3 and the welding torch 1, respectively. The substrate 3 is a metal block with a central through-hole and has an annular inner cavity. The inner cavity of the substrate 3, a water pump, and a cooling water tank 4 are circulated together. A first thermocouple 5 is installed at the water inlet of the substrate 3, and a second thermocouple 6 is installed at the water outlet. The welding torch 1 is positioned above the central through-hole of the substrate 3, and a calorimeter is positioned below the substrate 3. A coil carrying direct current can be installed between the substrate 3 and the calorimeter to generate a constant magnetic field. The substrate 3 serves as an electrode, and the calorimeter is placed on a balance 9, which can be an electronic balance.

[0022] Specific Implementation Method Two: Combining Figure 1 This embodiment describes a heat generation measuring device at the end of an AC arc substrate that considers evaporation phase change. The metal block is a copper block, and the water-cooled copper block is square when viewed from above. The water inlet and outlet of the inner cavity are located on both sides of the horizontally arranged substrate 3. The water pump fills the substrate cavity and then circulates the water.

[0023] Specific implementation method three: Combining Figure 1 This embodiment describes a heat generation measuring device at the end of an AC arc substrate that considers evaporation phase change. The calorimeter is a solid copper calorimeter, comprising: a temperature-sensing copper block 7, a heat-insulating quartz cotton layer 8, and a third thermocouple 12. The temperature-sensing copper block 7 is wrapped with the heat-insulating quartz cotton layer 8. Several third thermocouples 12 are arranged equidistantly from top to bottom on the temperature-sensing copper block 7, with the number of third thermocouples 12 being three to seven.

[0024] Specific implementation method four: Combination Figure 1 This embodiment of the AC arc substrate end heat generation measurement device considering evaporation phase change further includes a thermocouple acquisition card 10 and a PC terminal 11. The first thermocouple 5, the second thermocouple 6, and the third thermocouple 12 are electrically connected to the PC terminal 11 through the thermocouple acquisition card 10.

[0025] Specific Implementation Method Five: Combining Figure 1-4 This embodiment describes a method for measuring heat generation at the end of an AC arc substrate that considers evaporation phase change. The method utilizes the aforementioned device for measuring heat generation at the end of an AC arc substrate that considers evaporation phase change and includes the following steps: Step 1: Circulate water into the inner cavity of substrate 3 and record the temperatures of the first thermocouple 5 and the second thermocouple 6; measure the dynamic water temperature evolution of the first thermocouple 5 and the second thermocouple 6, and wait for the stabilization moment to record the temperature difference to avoid measurement errors caused by the thermal inertia of water and improve measurement accuracy. Step 2: Place a baffle above the calorimeter to isolate the effects of heat; Step 3: The welding torch 1 ignites an arc, which is established between the welding torch 1 and the substrate 3, and generates molten droplets; the arc heats the water-cooled copper block, and the molten droplets fall from the central through hole (hole); Step 4: Set the arc ignition time as follows Δt (s), and wait for the inlet and outlet water temperature curves of substrate 3 to stabilize; Step 5: Utilize the temperature difference between the inlet and outlet water at a stable moment ( Temp 2 -Temp 1) Calculate the heat transfer of the electric arc to the substrate 3, which is the substrate heat; Step 6: Apply a constant magnetic field below substrate 3 to deflect the arc tail flame and separate it from the falling trajectory of the molten droplet; by using an external magnetic field to separate the arc tail flame and the molten droplet trajectory, the arc tail flame can be prevented from heating the solid calorimeter and interfering with the measurement of the molten droplet temperature, thereby improving the accuracy of the molten droplet temperature measurement. Step 7: Place the calorimeter on the electronic balance 9, 120mm below the water-cooled copper block; observe the electronic balance and record the mass of the solid calorimeter before the baffle is removed. m 1; Step 8: Remove the baffle to allow the thermometric copper block 7 (solid copper block) to collect the falling molten droplets for 20 seconds, then extinguish the arc; observe the electronic balance and record the mass of the solid calorimeter. m 2; and calculate the mass of the collected molten droplets ( m 2 -m 1) A solid copper calorimeter is used to measure the temperature of the molten droplet. Four to eight thermocouples are arranged from top to bottom at different heights of the copper cylinder in the solid copper calorimeter. The average value of the collected temperature results is taken to avoid the adverse effects of the lag in heat conduction on the temperature measurement results. An infrared thermal imager is used to detect the temperature loss of the molten droplet after falling to a certain height, and this part of the temperature loss is compensated to the molten droplet temperature measured by the solid calorimeter to obtain a more accurate temperature value of the molten droplet itself. Step 9: Set the wire feeding speed of wire feeder 13 v w The amount of metal evaporated per unit time is calculated according to Formula 1. ms The mass of the molten droplet was recorded using a balance and compared with the mass transfer mass of the wire feeding process to obtain the metal evaporation amount. Based on this, the electrode heat generated by evaporation during the electric arc heat treatment process was calculated, which is not negligible in electrode heat generation. Step 10: Cover the surface of the solid copper block with quartz wool to reduce heat loss from the molten droplets; Step 11: Observe the third thermocouple 12. When the temperature stabilizes, record the temperature rise of the copper block. This invention utilizes a consumable electrode arc welding power source to ignite an arc and generate molten droplets between a welding wire and a water-cooled copper block with a circular hole. Thermometers are installed at the inlet and outlet of the water-cooled copper block to collect the inlet and outlet water temperatures in real time, used to calculate the heat transfer of the arc to the substrate. After the molten droplet passes through the circular hole of the water-cooled copper block, an external magnetic field is used to deflect the arc tail flame, and a solid copper calorimeter is used to measure the heat of the molten droplet. Simultaneously, a balance is used to record the mass of the solidified metal, and the evaporation rate is calculated in conjunction with the wire feeding mass. The heat generated at the welding wire end is equal to the sum of the molten droplet heat and the enthalpy change of evaporation; the heat generated at the substrate end is equal to the heat required for the temperature rise of the inlet and outlet cooling water. By adjusting the AC current waveform, the heat generated at the electrode end under different duty cycles is obtained, thereby solving the heat generation at the welding wire end and the substrate end under both positive and negative polarities.

[0026] Specific Implementation Method Six: Combination Figure 1-4 This embodiment describes a method for measuring heat generation at the end of an AC arc substrate that considers evaporation phase change. In step one, the distance between the lower end of the nozzle of the welding torch 1 and the upper surface of the substrate 3 is 10-12 mm, and the sampling rate of the data acquisition card is 2-10. In step two, the distance between the baffle and the upper surface of the calorimeter is 20-25mm; In step seven, the distance between the upper end of the calorimeter and the bottom of the substrate 3 is 120-130 mm; In step eight, the droplet collection time is 20-22 seconds.

[0027] Specific implementation method seven: Combining Figure 1-4 This embodiment describes a method for measuring heat generation at the end of an AC arc substrate that considers evaporation phase change. In step nine, the amount of metal evaporation per unit time is calculated according to formula (1). m s ; (1) in: R w The diameter of the wire. ρ It is the density of metallic materials; t It is the time for collecting molten droplets; In step eleven, when the temperature stabilizes, the average temperature change curve is used as a reference. Temp ave Record the temperature rise of the copper block ( Δ Tempave ); (2).

[0028] Specific implementation method eight: Combination Figure 1-4 This embodiment, which considers the evaporation phase change of the AC arc substrate end heat generation measurement method, further includes: Step 12: Repeat steps 1 to 11 multiple times, three times or more, to create error bars and enhance the reliability of the data; Step 13: Adjust the AC arc duty cycle and repeat steps 1 to 12 to obtain the unit heat of the inner substrate, the heat of the molten droplets, and the metal evaporation rate under different duty cycles.

[0029] Specific Implementation Method Nine: Combining Figure 1-4 This embodiment describes a method for measuring heat generation at the end of an AC arc substrate that considers evaporation phase change. It utilizes the cumulative heat generation power at different stages to transform a rapidly changing physical quantity that cannot be directly measured into a macroscopically measurable physical quantity, and then solves the system of equations. The calculation method and formulas are as follows: The formula for calculating the thermal properties of the substrate is shown in (3): (3) The formula for calculating heat generation at the end of the wire is shown in (4): (4) The positive polarity stage (EP) is defined as the stage where the wire is connected to the positive electrode; at this time, the heat generation power at the wire end is ( P w ) EP The heat generation power at the substrate end is ( P b ) EP The reverse polarity stage (EN, Electronegative) is when the wire is connected to the negative electrode; at this time, the heat generated at the wire end is ( P w ) EN The heat generation power at the substrate end is ( P b ) EN The alternating current arc period is T The positive half-cycle is T EP The negative half-cycle is T EN The droplet collection time is t , c wat The specific heat capacity of cooling water, Q wat For cooling water flow rate, H mThe latent heat of molten wire, c cop The specific heat capacity of the solid copper block. m cop The mass of the solid copper block; the two unknowns in formulas (3) and (4) are used to solve the heat generation of the electrode under different polarities of the AC arc by solving the simultaneous equations based on the results of multiple sets of experiments under different duty cycles, and to analyze the reliability of the measurement results. This invention takes into account both the heat transfer of the welding wire end and the workpiece end by the AC arc, and is applicable to both consumable and non-consumable AC arcs, making it suitable for a wider range of scenarios. It considers the melting and evaporation of the welding wire end, making the heat transfer measurement more consistent with reality and the measurement results more reliable. It adopts a calculation method that combines experimentation and theoretical derivation, and the workpiece end remains fixed during the heat generation measurement process, ensuring continuous and stable arc combustion. Therefore, this invention has higher measurement feasibility.

[0030] Specific Implementation Method Ten: Combining Figure 1-4 This embodiment describes a method for measuring heat generation at the end of an AC arc substrate that considers evaporation phase change. The welding torch 1 uses wire made of metals with low melting points, such as aluminum, magnesium, and copper.

[0031] Example 1: according to Figure 1 The illustrated AC arc substrate end-heat generation measurement device considering evaporation phase change includes a fuse system, a substrate heat measurement system, a droplet heat measurement system, and a metal evaporation measurement system. The fuse system relies on a consumable electrode arc welding power source to ignite an arc and generate a droplet between the welding wire and a water-cooled copper block with a circular hole. Thermometers are installed at the inlet and outlet of the water-cooled copper block to collect the inlet and outlet water temperatures in real time, which are used to calculate the heat transfer of the arc to the substrate. After the droplet passes through the circular hole of the water-cooled copper block, an external magnetic field is used to deflect the arc tail flame, and a solid copper calorimeter is used to measure the heat of the droplet. At the same time, a balance is used to record the mass of the solidified metal, and the evaporation amount is calculated in conjunction with the wire feeding mass. Therefore, the heat generation at the welding wire end is equal to the sum of the droplet heat and the enthalpy change of evaporation; the heat generation at the substrate end is equal to the heat required for the temperature rise of the inlet and outlet cooling water. By adjusting the alternating current waveform, the heat generation at the electrode tip under different duty cycles is obtained, thereby solving the heat generation at the welding wire tip and substrate tip under positive and negative polarities. This invention decomposes the heat generation at the welding wire tip into droplet heat and enthalpy change of vaporization, and uses a magnetic field and a perforated water-cooled copper block to achieve simultaneous measurement of both. Furthermore, by adjusting the positive and negative polarity duty cycles, the heat generation at different stages of the alternating current arc is solved. This has significant theoretical importance and value for studying the heat transfer mechanism of alternating current arcs, controlling the heat generation of arc welding and additive manufacturing, and optimizing forming and microstructure properties. The welding wire system includes: a consumable electrode arc welding power supply system, a cooling water tank 4, and a perforated water-cooled copper block (substrate 3). The consumable electrode arc welding power supply system includes: a welding machine, a wire feeder, a welding torch, and a shielding gas. The arc welding power supply ground wire is connected to the perforated water-cooled copper block, and the other wire is connected to the welding torch. The welding torch is located directly above the hole in the water-cooled copper block, and after the arc is ignited, the arc is established between the welding torch and the water-cooled copper block. The substrate thermal measurement system includes: a cooling water tank, a perforated water-cooled copper block, a first thermocouple, and a second thermocouple; the first thermocouple is located at the water inlet of the water-cooled copper block and is used to measure the water temperature evolution at the inlet; the second thermocouple is located at the water outlet of the water-cooled copper block and is used to measure the water temperature evolution at the outlet. The molten droplet heat measurement system includes: a constant magnetic field, a solid copper block, three to seven third thermocouples, quartz wool, a thermocouple acquisition card, and a PC terminal; the constant magnetic field is located below the perforated water-cooled copper block and is used to separate the arc tail flame and molten droplets; the third thermocouples are inserted into the solid copper block, and the solid copper block is wrapped with quartz wool; the thermocouple acquisition card collects the thermocouple temperatures and connects to the PC terminal to display and save the data; The metal evaporation measurement system includes: an electronic balance and a solid calorimeter to be measured, wherein the solid calorimeter includes a solid copper block, quartz wool, and a third thermocouple; the electronic balance records the total mass of the molten droplet. A device for measuring the heat generation at the tip of an AC arc electrode that considers evaporation phase change requires measuring the heat generation at the electrode tip, namely the substrate heat, the molten droplet heat, and the amount of metal evaporation during the molten wire process. according to Figure 1-4 The method for measuring heat generation at the end of an AC arc substrate considering evaporation phase change, as shown, includes the following steps during the substrate heat measurement process: Step 1: Position the welding torch directly above the cavity of the water-cooled copper block, with a nozzle 10mm away from the water-cooled copper block; place the first and second thermocouples at the inlet and outlet of the substrate respectively; turn on the water-cooled tank; start recording the thermocouple temperatures; and set the sampling rate of the data acquisition card to 10. Step 2: Place a baffle 20mm above the solid copper calorimeter to isolate the solid copper calorimeter from the heat source; Step 3: The welding torch is ignited, and an electric arc is established between the welding torch and the water-cooled copper block, producing molten droplets; the electric arc heats the water-cooled copper block, and the molten droplets fall from the hole; Step 4: Set the arc ignition time as follows Δt (s), and wait for the inlet and outlet water temperature curves of the water-cooled copper block to stabilize; Step 5: Utilize the temperature difference between the inlet and outlet water at a stable moment ( Temp 2 -Temp 1) The heat transfer from the electric arc to the water-cooled copper block is calculated, which is the heat of the substrate; The steps for measuring the heat of molten droplets and the amount of metal evaporation are as follows: Step 6: Apply a constant magnetic field below the perforated water-cooled copper block to deflect the arc tail flame and separate it from the trajectory of the falling droplet; Step 7: Place the solid copper calorimeter on the electronic balance, 120mm below the water-cooled copper block; observe the electronic balance and record the mass of the solid calorimeter before the baffle is removed. m 1; Step 7: Remove the baffle to allow the solid copper block to collect the falling molten droplets for 20 seconds, then extinguish the arc; Step 8: Observe the electronic balance and record the mass of the solid calorimeter. m 2; and calculate the mass of the collected molten droplets ( m 2 - m 1); Step 9: Record the wire feeding speed v w The amount of metal evaporated per unit time is calculated according to formula (1). m s ,in R w The diameter of the wire. ρ It is the density of metallic materials; t It is the time for collecting molten droplets; (1) Step 10: Cover the surface of the solid copper block with quartz wool to reduce heat loss from the molten droplets; Step 11: Observe the third thermocouple. When the temperature stabilizes, calculate based on the average temperature change curve. Temp ave Record the temperature rise of the copper block ( ΔTemp ave ); (2) Step 12: Repeat the above steps three or more times to create error bars and enhance the reliability of the data; Step Thirteen: Adjust the AC arc duty cycle, repeat steps one through twelve, to obtain the unit heat of the inner substrate, the heat of the molten droplets, and the amount of metal evaporation under different duty cycles; The method for calculating heat generation at the electrode tip is as follows: The positive polarity stage (EP) is defined as the stage where the wire is connected to the positive electrode; at this time, the heat generation power at the wire end is ( P w ) EP The heat generation power at the substrate end is ( P b ) EP The reverse polarity stage (EN, Electronegative) is when the wire is connected to the negative electrode; at this time, the heat generated at the wire end is ( P w )EN The heat generation power at the substrate end is ( P b ) EN The alternating current arc period is T The positive half-cycle is T EP The negative half-cycle is T EN The droplet collection time is t , c wat The specific heat capacity of cooling water, Q wat For cooling water flow rate, H m The latent heat of molten wire, c cop The specific heat capacity of the solid copper block. m cop The mass of the solid copper block is given. The formula for calculating the heat of the substrate is shown in (3), and the formula for calculating the heat generated at the wire end is shown in (4).

[0032] [( P b ) EP * T EP +( P b ) EN * T EN ] / T = c wat *Q wat * ( Temp 2 -Temp 1)(3) [( P w ) EP * T EP +( P w ) EN * T EN ] *t / T =m s *H m + c cop *m cop *ΔTemp ave (4) There are two unknowns in formulas (3) and (4). Based on the results of multiple sets of experiments under different duty cycles, the simultaneous equations are used to solve the heat generation of the electrode under different polarities of the AC arc, and the reliability of the measurement results is analyzed. To address the differences in heat generation at different stages of an alternating current arc, the rapidly changing physical quantity that cannot be directly measured can be transformed into a macroscopically measurable physical quantity by accumulating the heat generation power at different stages. A system of simultaneous equations can then be solved. Furthermore, multiple sets of experiments (more than two sets) can be conducted to solve for the two variables, which can evaluate the reliability of the measurement results.

[0033] The fused wire system relies on a consumable electrode arc welding power source to ignite an arc and generate molten droplets between the welding wire and a water-cooled copper block with a circular hole. Thermometers are installed at the inlet and outlet of the water-cooled copper block to collect the inlet and outlet water temperatures in real time, which are used to calculate the heat transfer of the arc to the substrate. After the molten droplets pass through the circular hole of the water-cooled copper block, an external magnetic field is used to deflect the arc tail flame, and a solid copper calorimeter is used to measure the heat of the molten droplets. At the same time, a balance is used to record the mass of the solidified metal, and the evaporation rate is calculated in conjunction with the mass of the wire feed. The heat generated at the welding wire end is equal to the sum of the molten droplet heat and the enthalpy change of evaporation. The heat generated at the substrate end is equal to the heat required for the temperature rise of the inlet and outlet cooling water. Finally, by adjusting the AC current waveform, the heat generated at the electrode end under different duty cycles is obtained. After multiple experiments, the heat generated at the welding wire end and the substrate end under positive and negative polarities is solved. This invention is of great significance to the fields of arc heat processing and arc physics measurement.

[0034] Example 2: Using the device from Example 1, such as Figure 1 As shown in the figure, connect the required equipment. The power source used in the additive manufacturing process is a consumable electrode arc welding power source (CMT, Cold Metal Transfer). By adjusting the relative position of the welding torch and the perforated water-cooled copper block, the hole of the perforated water-cooled copper block and the center of the welding torch are kept on the same axis. The nozzle end face is 10mm away from the upper surface of the water-cooled copper block. The method is as follows Figure 2 As shown, the specific steps include: Step 1: Position the welding torch directly above the cavity of the water-cooled copper block, with a nozzle 10mm away from the water-cooled copper block; place the first and second thermocouples at the inlet and outlet of the substrate, respectively; turn on the water-cooled tank; start recording the thermocouple temperatures; and set the sampling rate of the data acquisition card to 2. Step 2: Place a baffle 20mm above the solid copper calorimeter to isolate the solid copper calorimeter from the heat source; Step 3: The welding torch is ignited, and an electric arc is established between the welding torch and the water-cooled copper block, producing molten droplets; the electric arc heats the water-cooled copper block, and the molten droplets fall from the hole; Step 4: Set the arc ignition time as follows Δt (s), and wait for the inlet and outlet water temperature curves of the water-cooled copper block to stabilize; Step 5: Utilize the temperature difference between the inlet and outlet water at a stable moment ( Temp 2 -Temp1) The heat transfer from the electric arc to the water-cooled copper block is calculated, which is the substrate heat; the inlet and outlet water temperature evolution curves are as follows: Figure 3 As shown; Step 6: Apply a constant magnetic field below the perforated water-cooled copper block to deflect the arc tail flame and separate it from the trajectory of the falling droplet; Step 7: Place the solid copper calorimeter on the electronic balance, 120mm below the water-cooled copper block; observe the electronic balance and record the mass of the solid calorimeter before the baffle is removed. m 1; Step 7: Remove the baffle to allow the solid copper block to collect the falling molten droplets for 20 seconds, then extinguish the arc; Step 8: Observe the electronic balance and record the mass of the solid calorimeter. m 2; and calculate the mass of the collected molten droplets ( m 2 - m 1); Step 9: Record the wire feeding speed v w The amount of metal evaporated per unit time is calculated according to formula (1). m s ,in R w The diameter of the wire. ρ It is the density of metallic materials; t It is the time for collecting molten droplets; (1) Step 10: Cover the surface of the solid copper block with quartz wool to reduce heat loss from the molten droplets; Step 11: Observe thermocouples 3-7. When the temperature stabilizes, analyze the average temperature change curve. Temp ave ,like Figure 4 As shown. The temperature rise of the copper block was recorded. ΔTemp ave ); (2) Step 12: Repeat the above steps three or more times to create error bars and enhance the reliability of the data; Step Thirteen: Adjust the AC arc duty cycle, repeat steps one through twelve, to obtain the unit heat of the inner substrate, the heat of the molten droplets, and the amount of metal evaporation under different duty cycles; The positive polarity stage (EP) is defined as the stage where the wire is connected to the positive electrode; at this time, the heat generation power at the wire end is ( P w ) EP The heat generation power at the substrate end is ( P b )EP The reverse polarity stage (EN, Electronegative) is when the wire is connected to the negative electrode; at this time, the heat generated at the wire end is ( P w ) EN The heat generation power at the substrate end is ( P b ) EN The alternating current arc period is T The positive half-cycle is T EP The negative half-cycle is T EN The droplet collection time is t , c wat The specific heat capacity of cooling water, Q wat For cooling water flow rate, H m The latent heat of molten wire, c cop The specific heat capacity of the solid copper block. m cop The mass of the solid copper block is given. The formula for calculating the heat of the substrate is shown in (3), and the formula for calculating the heat generated at the wire end is shown in (4).

[0035] [( P b ) EP * T EP +( P b ) EN * T EN ] / T = c wat *Q wat * ( Temp 2 -Temp 1)(3) [( P w ) EP * T EP +( P w ) EN * T EN ] *t / T =m s *H m + c cop *mcop *ΔTemp ave (4) There are two unknowns in formulas (3) and (4). Based on the results of multiple sets of experiments under different duty cycles, the simultaneous equations are used to solve the heat generation of the electrode under different polarities of the AC arc, and the reliability of the measurement results is analyzed.

[0036] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A heat generation measuring device for the end of an AC arc substrate considering evaporation phase change, wherein a power supply (2) is connected to the substrate (3) and the welding torch (1) respectively, characterized in that: The substrate (3) is a metal block with a central through hole. The inner cavity of the substrate (3) and the cooling water tank (4) are connected in a loop. The inlet of the substrate (3) is equipped with a first thermocouple (5), and the outlet of the substrate (3) is equipped with a second thermocouple (6). A welding torch (1) is correspondingly arranged above the central through hole of the substrate (3). A calorimeter is arranged below the substrate (3) and is placed on a balance (9).

2. The AC arc substrate end heat generation measuring device considering evaporation phase change according to claim 1, characterized in that: The metal block is a copper block.

3. The AC arc substrate end heat generation measuring device considering evaporation phase change according to claim 1 or 2, characterized in that: Calorimeters include: The outer side of the temperature measuring copper block (7) is wrapped with a heat-insulating quartz wool layer (8), and the temperature measuring copper block (7) has a third thermocouple (12).

4. The AC arc substrate end heat generation measuring device considering evaporation phase change according to claim 3, characterized in that: It also includes a thermocouple acquisition card (10) and a PC terminal (11). The first thermocouple (5), the second thermocouple (6), and the third thermocouple (12) are connected to the PC terminal (11) through the thermocouple acquisition card (10).

5. A method for measuring heat generation at the end of an AC arc substrate considering evaporation phase change, characterized in that: The AC arc substrate end heat generation measuring device considering evaporation phase change as described in any one of claims 1-4 includes the following steps: Step 1: Circulate water into the inner cavity of the substrate (3) and record the temperatures of the first thermocouple (5) and the second thermocouple (6); Step 2: Place a baffle above the calorimeter; Step 3: The welding torch (1) ignites an arc, and an electric arc is established between the welding torch (1) and the substrate (3), generating molten droplets; the electric arc heats the water-cooled copper block, and the molten droplets fall from the central through hole; Step 4: Set the arc ignition time as follows Δt (s), and wait for the inlet and outlet water temperatures of the substrate (3) to stabilize; Step 5: Calculate the heat transfer of the electric arc to the substrate (3) using the temperature difference between the inlet and outlet water at the steady moment; Step 6: Apply a constant magnetic field below the substrate (3) to deflect the arc tail flame and separate it from the falling trajectory of the molten droplet; Step 7: Record the mass of the solid calorimeter before the baffle is removed. m 1; Step 8: Remove the baffle to allow the measuring copper block (7) to collect the falling molten droplets, then extinguish the electric arc; record the mass of the solid calorimeter. m 2; and calculate the mass of the collected molten droplets. m 2 -m 1; Step 9: Record the wire feeding speed v w Calculate the amount of metal evaporated per unit time. m s ; Step 10: Cover the surface of the solid copper block with quartz wool to reduce heat loss from the molten droplets; Step 11: When the temperature of the third thermocouple (12) is stable, record the temperature rise of the copper block.

6. The method for measuring heat generation at the end of an AC arc substrate considering evaporation phase change according to claim 5, characterized in that: In step one, the distance between the lower end of the nozzle of the welding gun (1) and the upper surface of the substrate (3) is 10-12mm, and the sampling rate of the data acquisition card is 2-10. In step two, the distance between the baffle and the upper surface of the calorimeter is 20-25mm; In step seven, the distance between the upper end of the calorimeter and the bottom of the substrate (3) is 120-130 mm; In step eight, the droplet collection time is 20-22 seconds.

7. The method for measuring heat generation at the end of an AC arc substrate considering evaporation phase change according to claim 5, characterized in that: In step nine, the amount of metal evaporated per unit time is calculated according to formula (1). m s ; (1) in: R w The diameter of the wire. ρ It is the density of metallic materials; t It is the time for collecting molten droplets; In step eleven, based on the average temperature change curve Temp ave Record the temperature rise of the copper block ΔTemp ave ; (2)。 8. The method for measuring end-heat generation of an AC arc substrate considering evaporation phase change according to any one of claims 5-7, characterized in that: Also includes: Repeat steps one through eleven above three times or more to create error bars and enhance the reliability of the data. Adjust the AC arc duty cycle and repeat all the above steps to obtain the unit substrate heat, droplet heat and metal evaporation amount under different duty cycles.

9. The method for measuring heat generation at the end of an AC arc substrate considering evaporation phase change according to claim 8, characterized in that: By accumulating the heat generation power at different stages, rapidly changing physical quantities that cannot be directly measured are transformed into macroscopically measurable physical quantities, and a system of simultaneous equations is solved. The formula for calculating the thermal properties of the substrate is shown in (3): (3) The formula for calculating heat generation at the end of the wire is shown in (4): (4) The positive polarity stage is defined as the stage where the wire is connected to the positive electrode; at this time, the heat generation power at the wire end is ( P w ) EP The heat generation power at the substrate end is ( P b ) EP ; The reverse polarity stage is the stage where the wire is connected to the negative electrode; at this time, the heat generation power at the wire end is ( P w ) EN The heat generation power at the substrate end is ( P b ) EN The alternating current arc period is T The positive half-cycle is T EP The negative half-cycle is T EN The droplet collection time is t , c wat The specific heat capacity of cooling water, Q wat For cooling water flow rate, H m The latent heat of molten wire, c cop The specific heat capacity of the solid copper block. m cop The mass of the solid copper block; the two unknowns in formulas (3) and (4) are used to solve the heat generation of the electrode under different polarities of the AC arc by solving the simultaneous equations based on the results of multiple sets of experiments under different duty cycles, and the reliability of the measurement results is analyzed.

10. The method for measuring heat generation at the end of an AC arc substrate considering evaporation phase change according to claim 8, characterized in that: The wire used is made of aluminum, magnesium, and copper.

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