A new method for rotary friction welding of tube-sheet and rod-sheet

Abstract

The present invention provides a novel method for rotary friction welding of tube plates and rod plates, which comprises the following steps: (a) preparation stage of welding parts; (b) clamping stage; (c) contact stage; (d) penetration stage; (e) hovering stage; (f) emergency stop stage; (g) upsetting maintenance stage; (h) end of welding; (i) post-welding treatment. In the novel method for rotary friction welding of tube plates and rod plates of the present invention, heat is generated by the high-speed friction between the welding surfaces of the tube or rod to be welded and the plate to be welded. At the same time, heat is assisted to be generated by the contact resistance between the welding surfaces of the tube or rod to be welded and the plate to be welded, so as to realize the stable solid-phase connection between the tube and the plate, and between the rod and the plate. It is particularly suitable for the connection of tube plates and rod plates between heterogeneous materials (such as aluminum and steel, aluminum and copper, aluminum and magnesium, etc.), and has simple design, convenient installation and wide applicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of friction welding, and particularly relates to a novel method for rotary friction welding of tube plates and rod plates. Background Art

[0002] Friction welding technology is a typical solid-state joining technology, which has many advantages such as good quality of welded joints, being suitable for joining the same or dissimilar materials, energy saving, pollution-free, low heat input, good microstructure and mechanical properties of welds. Especially its general applicability in the field of joining dissimilar materials has been widely used in manufacturing fields such as aviation, aerospace, shipbuilding, automobiles, and rail trains.

[0003] The Welding Institute of the United Kingdom has developed a method for welding materials with different hardnesses using embedded friction welding technology. This process is to immerse a material with higher hardness into a softer material, and then rotate the harder material. Frictional heat is generated between the two materials to make the softer material reach the thermoplastic state; the plastic material generates plastic flow at the friction interface. When the welded part cools, a metallurgical bond is formed at the interface, and the surrounding plastic metal solidifies to generate mechanical interlocking, obtaining an embedded friction welding joint. However, this technology is only suitable for rod-to-plate connection, and due to the lack of forced plastic shaping of the welded joint during the welding upsetting process, the welded joint has serious deformation and unstable quality.

[0004] The Welding Institute of the United Kingdom has also developed a new solid-phase joining technology - friction stir surfacing. Friction stir surfacing is formed by overlapping a certain number of friction stir surfacing units; during the welding process, a hole to be filled is prefabricated on the workpiece to be welded, a welding rod smaller than the diameter of the welding hole is selected for matching, the welding rod rotates at a certain speed, and welding is carried out under the action of axial pressure. Heat is generated by the friction between the welding rod and the welding hole to form a local plastic layer. The plastic metal continuously breaks away from the friction interface under the extrusion of the axial pressure and flows into the gap between the welding rod and the welding hole to fill the gap between the welding rod and the welding hole. Then the rotation stops, and a greater axial pressure is applied axially. After maintaining for a period of time, it is removed, and the welding process is completed. However, this technology is only suitable for rod-to-plate connection, and due to the lack of forced plastic shaping of the welded joint during the welding upsetting process, the welded joint has serious deformation and unstable quality.

[0005] In a Chinese patent application for invention with the publication number CN1876307A and the publication date of December 13, 2006, a method for friction welding of tube plates is disclosed, which can be used for welding various non-ferrous metals such as aluminum alloys, magnesium alloys, copper and copper alloys, and steels. However, due to the lack of forced plastic shaping of the welded joint during the welding upsetting process, the welded joint has serious deformation and unstable quality.

[0006] Therefore, in order to solve the technical problems of deformation and unstable quality of the rod-to-plate welded joint and tube-to-plate connection in the existing solid-phase joining technology, a novel method for rotary friction welding of tube plates and rod plates is proposed. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a new method for rotary friction welding of tube plates and bar plates in view of the deficiencies of the prior art. This method relies on the high-speed friction between the welding surfaces of the tube or bar to be welded and the plate to be welded to generate heat. At the same time, the contact resistance between the welding surfaces of the tube or bar to be welded and the plate to be welded is used to assist in heat generation, so as to achieve stable solid-phase connection between the tube and the plate, and between the bar and the plate.

[0008] This solution is achieved through the following technical measures: A new method for rotary friction welding of tube plates and bar plates, which includes the following steps:

[0009] (a) Welding part preparation stage: The material hardness of the plate to be welded is less than or equal to 20 HV of the microhardness value of the material of the tube or bar to be welded, and the thickness of the plate to be welded is greater than or equal to 3 mm;

[0010] (b) Clamping stage: Fix the tube or bar to be welded on the tool holder through fastening screws, and fix the plate to be welded on the base;

[0011] (c) Contact stage: After the welding surfaces of the tube or bar to be welded and the plate to be welded come into contact, the main shaft drives the tube or bar to be welded to rotate at a high speed of 300 - 2500 r / min while transmitting an axial upsetting force through the tool holder fixedly connected to it. The plate to be welded is fixed on the base and remains stationary. The tube or bar to be welded stays at this axial position for 10 - 30 s, and the heat generated by the high-speed friction between the welding surfaces of the tube or bar to be welded and the plate to be welded plasticizes the contact surface material;

[0012] (d) Penetration stage: When the contact surface material is plasticized, the tube or bar to be welded penetrates axially at a speed of 0 - 5 mm / min, and the penetration depth is less than or equal to 0.5 mm;

[0013] (e) Hovering stage: After the tube or bar to be welded penetrates in place, the tube or bar to be welded continues to rotate at this axial position for 5 - 10 s to fully plasticize the contact surface material;

[0014] (f) Emergency stop stage: After the hovering stage ends, the rotating tube or bar to be welded stops rotating within 1 s, and continues to maintain the upsetting force on the tube or bar to be welded for 5 - 15 s;

[0015] (g) Upsetting maintenance stage: After the emergency stop stage ends, continue to maintain the upsetting force on the tube or bar to be welded for 5 - 15 s;

[0016] (h) Welding end: After the upsetting and maintaining stage ends, loosen the fastening screw between the pipe or rod to be welded and the tool shank, lift the tool shank, and the welding is completed. Finally, a solid-phase connection welding joint is formed to achieve the solid-phase connection between the pipe and the plate or between the rod and the plate;

[0017] (i) Post-welding treatment: After welding is completed, remove the flash on the inner and outer sides of the welding joint of the pipe or the flash on the outer side of the welding joint of the rod.

[0018] Preferably, a mandrel is arranged inside the pipe to be welded. The mandrel is fixedly installed on the tool shank through a fastening screw. The outer contour of the cross-section of the mandrel is the same as the inner contour of the pipe to be welded. The mandrel and the pipe to be welded are in clearance fit, and the clearance is 0.03 - 0.05 mm.

[0019] Preferably, the welding surface of the rod to be welded is a plane consistent with the cross-section of the rod to be welded, or a characteristic body in the shape of a cone, frustum of a cone, or sphere is integrally formed at the welding end of the rod to be welded. The height of the characteristic body is less than or equal to 0.3 mm, and the diameter of the contact position between the characteristic body and the welding end of the rod to be welded is less than or equal to two-thirds of the inscribed circle diameter of the cross-section of the rod to be welded.

[0020] Preferably, the strength value obtained by dividing the upsetting force by the cross-sectional area of the pipe or rod to be welded is less than or equal to four-fifths of the material yield strength of the pipe or rod to be welded.

[0021] Preferably, the roughness of the welding surfaces of the pipe to be welded, the rod to be welded, and the plate to be welded is Ra6.3 - Ra50; if placed in an air environment, welding is completed within 2 hours after the roughness treatment of the welding surface; if placed in an environment with a humidity less than 60%, welding is completed within 1 day after the roughness treatment of the welding surface; if placed in an inert gas environment, welding is completed within 30 days after the roughness treatment of the welding surface.

[0022] Preferably, a support sleeve is sleeved outside the pipe or rod to be welded. The support sleeve is fixedly installed on the tool shank through a fastening screw. The inner contour of the cross-section of the support sleeve is the same as the outer contour of the pipe or rod to be welded. The pipe or rod to be welded and the support sleeve are in clearance fit, and the clearance is 0.03 - 0.05 mm.

[0023] Preferably, after welding is completed, there is a gap of 0.5 - 1 mm between the lower end surface of the support sleeve and the upper surface of the plate to be welded, and there is a gap of 0 - 0.05 mm between the lower end surface of the mandrel and the upper surface of the plate to be welded.

[0024] Preferably, the materials of the support sleeve and the mandrel are both die steel, and the surfaces of the support sleeve and the mandrel are respectively coated with ceramic coatings.

[0025] Preferably, during the welding process, the pipe or rod to be welded is connected to the positive or negative pole of the welding power source, and the plate to be welded is connected to the negative or positive pole of the welding power source. After the pipe or rod to be welded contacts the plate to be welded, power is supplied, and heat is generated through the contact resistance between the welding surface of the pipe or rod to be welded and the welding surface of the plate to be welded to assist in completing the welding;

[0026] The welding power source adopts a constant voltage control mode. During the welding process, the power-off time and the welding quality of the welded joint are determined by monitoring the current change in the circuit; when the welding current gradually increases and then stabilizes, the power supply is immediately cut off; the current value when the welding quality of the welded joint of different welding materials and welding structures is good is determined as the standard current value through experiments and built into the control system in the form of a database; after welding is completed, the measured current value in the monitoring circuit is monitored and fed back to the control system of the welding device, and the control system compares the monitored current value with the standard current value of the corresponding welding materials and welding structures to automatically detect and feedback the welding quality of the welded joint.

[0027] Preferably, the inner contour and outer contour of the cross-section of the pipe to be welded are both circular, square, rectangular, pentagonal or hexagonal, and the cross-section of the rod to be welded is circular, square, rectangular, pentagonal or hexagonal;

[0028] The main shaft is rotatably installed on the cross beam, and the upper end of the main shaft is fixedly connected to the output end of the main shaft motor, and the lower end is fixedly connected to the tool holder. The two ends of the cross beam are respectively fixed to the upper ends of the two columns, and the two columns and the base are fixed on the ground.

[0029] The beneficial effects of the present invention: In the novel tube-plate and rod-plate rotary friction welding method of the present invention, heat is generated by the high-speed friction between the welding surfaces of the pipe or rod to be welded and the plate to be welded. At the same time, heat is assisted to be generated through the contact resistance between the welding surfaces of the pipe or rod to be welded and the plate to be welded, realizing the stable solid-phase connection between the pipe and the plate, and between the rod and the plate. It is especially suitable for the connection of tube-plate and rod-plate between heterogeneous materials (such as aluminum-steel, aluminum-copper, aluminum-magnesium, etc.), and has a simple design, convenient installation and wide applicability. It can be seen that compared with the prior art, the present invention has outstanding substantive features and remarkable progress, and the beneficial effects of its implementation are also obvious. Description of the Drawings

[0030] Figure 1 It is a welding schematic diagram of the pipe or rod to be welded and the plate to be welded;

[0031] Figure 2 It is a combined schematic diagram of the pipe to be welded and the mandrel;

[0032] Figure 3 It is a structural schematic diagram of the rod to be welded;

[0033] Figure 4 It is a structural schematic diagram of the plate to be welded.

[0034] In the figure: 1 - spindle motor, 2 - spindle, 3 - tool holder, 4 - support sleeve, 5 - pipe or rod to be welded, 51 - clamping end of the pipe or rod to be welded, 52 - welding surface of the rod to be welded, 53 - feature body, 6 - plate to be welded, 61 - welding surface of the plate to be welded, 7 - base, 8 - cross beam, 9 - column, 10 - welding power source, 11 - mandrel. Specific implementation mode

[0035] To clearly illustrate the technical features of this solution, the following will elaborate on this solution through specific implementation modes and in combination with its attached drawings.

[0036] A new type of pipe - plate and rod - plate rotary friction welding method, which includes the following steps:

[0037] (a) Welding part preparation stage: To facilitate connection, the material hardness of the plate 6 to be welded is less than or equal to 20HV of the micro - hardness value of the material of the pipe or rod 5 to be welded, and the thickness of the plate 6 to be welded is greater than or equal to 3mm;

[0038] (b) Clamping stage: Fix the pipe or rod 5 to be welded on the tool holder 3 through fastening screws, fix the plate 6 to be welded on the base 7, the spindle 2 is rotatably installed on the cross beam 8, and the upper end of the spindle 2 is fixedly connected to the output end of the spindle motor 1, and the lower end is fixedly connected to the tool holder 3. The two ends of the cross beam 8 are respectively fixed to the upper ends of the two columns 9, and the two columns 9 and the base 7 are fixed on the ground;

[0039] (c) Contact stage: After the welding surface of the pipe or rod 5 to be welded contacts the welding surface of the plate 6 to be welded, the spindle 2 drives the pipe or rod 5 to be welded to rotate at a high speed of 300 - 2500 r / min through the tool holder 3 fixedly connected thereto while transmitting an axial upsetting force. The plate 6 to be welded is fixed on the base 7 and remains stationary. The pipe or rod 5 to be welded stays at this axial position for 10 - 30 s, and the heat generated by the high - speed friction between the welding surface of the pipe or rod 5 to be welded and the welding surface of the plate 6 to be welded plasticizes the contact surface material;

[0040] (d) Penetration stage: When the contact surface material is plasticized, the pipe or rod 5 to be welded penetrates axially at a speed of 0 - 5 mm / min, and the penetration depth is less than or equal to 0.5 mm;

[0041] (e) Hovering stage: After the pipe or rod 5 to be welded penetrates in place, the pipe or rod 5 to be welded continues to rotate at this axial position for 5 - 10 s to fully plasticize the contact surface material;

[0042] (f) Emergency stop stage: After the hovering stage ends, the pipe or rod 5 to be welded in a rotating state stops rotating within 1 s, and continues to apply upsetting force to the pipe or rod 5 to be welded and maintain it for 5 - 15 s;

[0043] (g) Upsetting maintenance stage: After the emergency stop stage ends, continue to apply upsetting force to the pipe or rod 5 to be welded and maintain it for 5 - 15 s;

[0044] (h) Welding completion: After the upsetting maintenance stage ends, loosen the fastening screw between the pipe or rod 5 to be welded and the tool holder 3, lift the tool holder 3, the welding is completed, and finally a solid-phase connected welded joint is formed, realizing the solid-phase connection between the pipe and the plate or between the rod and the plate, especially suitable for the connection between pipe and plate or rod and plate of heterogeneous materials;

[0045] (i) Post-welding treatment: After welding is completed, remove the flash on the inner and outer sides of the welded joint of the pipe or the flash on the outer side of the welded joint of the rod by means of less forceful techniques (such as grinding and polishing) to ensure that the welding quality of the welded joint is not affected while removing the welding flash.

[0046] Among them, a mandrel 11 is arranged inside the pipe to be welded, the mandrel 11 is fixedly installed on the tool holder 3 through a fastening screw, the outer contour of the cross-section of the mandrel 11 is the same as the inner contour of the pipe to be welded, and the inner and outer contours of the cross-section of the pipe to be welded are circular, square, rectangular, pentagonal or hexagonal. Of course, the inner and outer contours of the cross-section of the pipe to be welded can also be other required shapes. The mandrel 11 and the pipe to be welded are in clearance fit with a fit clearance of 0.03 - 0.05 mm to ensure that the main body of the pipe to be welded does not deform during the welding process and plays an auxiliary forming role.

[0047] The cross-section of the rod to be welded is circular, square, rectangular, pentagonal or hexagonal. Of course, the cross-section of the rod to be welded can also be other required shapes; the welding surface of the rod to be welded is a plane consistent with the cross-section of the rod to be welded, or a feature body 53 in the shape of a cone, frustum of a cone or sphere is integrally formed at the welding end of the rod to be welded. The feature body 53 in this structural form can increase frictional heat generation. To ensure that the feature body 53 is easy to plasticize and does not penetrate the plate 6 to be welded during the welding process, the height of the feature body 53 is less than or equal to 0.3 mm. To avoid difficult plasticization and excessive welding flash caused by the oversized feature body 53 during the welding process, the diameter of the contact position of the feature body 53 with the welding end of the rod to be welded is less than or equal to two-thirds of the inscribed circle diameter of the cross-section of the rod to be welded.

[0048] The strength value obtained by dividing the upsetting force by the cross-sectional area of the pipe or rod 5 to be welded is less than or equal to four-fifths of the material yield strength of the pipe or rod 5 to be welded to ensure that the main body of the pipe or rod 5 to be welded does not yield during the welding process so as to transmit torque and upsetting force.

[0049] To increase the heat generation effect of friction and contact resistance during the welding process, the roughness of the welding surfaces of the pipe fittings to be welded, rod parts to be welded, and plate parts 6 to be welded is Ra6.3 - Ra50 through technical means (such as mechanical and chemical corrosion). To prevent the oxidation of the welding surfaces from affecting the welding quality of the welded joints, if placed in an air environment, welding should be completed within 2 hours after the roughness treatment of the welding surfaces; if placed in an environment with a humidity less than 60%, welding should be completed within 1 day after the roughness treatment of the welding surfaces; if placed in an inert gas environment, welding should be completed within 30 days after the roughness treatment of the welding surfaces.

[0050] A support sleeve 4 is sleeved outside the pipe fitting to be welded or the rod part to be welded 5. The support sleeve 4 is fixedly installed on the tool holder 3 through fastening screws. The inner contour of the cross-section of the support sleeve 4 is the same as the outer contour of the pipe fitting to be welded or the rod part to be welded 5. The pipe fitting to be welded or the rod part to be welded 5 and the support sleeve 4 are in clearance fit with a clearance of 0.03 - 0.05 mm to ensure that the main body of the pipe fitting to be welded or the rod part to be welded 5 does not deform during the welding process.

[0051] After welding is completed, a gap of 0.5 - 1 mm is left between the lower end surface of the support sleeve 4 and the upper surface of the plate part 6 to be welded to ensure the discharge of material flash during the downward piercing process. The material of the support sleeve 4 is die steel, and a ceramic coating that does not adhere to metal materials is coated on the surface of the support sleeve 4 through technical means (such as spraying, electroplating, magnetron sputtering).

[0052] A gap of 0 - 0.05 mm is left between the lower end surface of the mandrel 11 and the upper surface of the plate part 6 to be welded to ensure the inner cavity forming during the pipe fitting welding process. The material of the mandrel 11 is die steel, and a ceramic coating that does not adhere to metal materials is coated on the surface of the mandrel 11 through technical means (such as spraying, electroplating, magnetron sputtering).

[0053] During the welding process, the pipe or rod 5 to be welded is connected to the positive or negative electrode of the welding power source 10, and the plate 6 to be welded is connected to the negative or positive electrode of the welding power source 10. After the pipe or rod 5 to be welded contacts the plate 6 to be welded, power is supplied, and heat is generated through the contact resistance between the welding surface of the pipe or rod 5 to be welded and the welding surface of the plate 6 to be welded to assist in completing the welding, so as to ensure obtaining a welding joint with stable quality. The welding power source 10 adopts a constant voltage control mode. During the welding process, the power-off time and the welding quality of the welding joint are determined by monitoring the current change in the circuit; when the welding current gradually increases and then stabilizes, the power supply is immediately cut off; the current value when the welding quality of the welding joint of different welding materials and welding structures is good is determined as the standard current value through experiments and is built into the control system in the form of a database; after welding is completed, the measured current value in the monitoring circuit is monitored and fed back to the control system of the welding device, and the control system compares the monitored current value with the standard current value corresponding to the welding material and welding structure to achieve automatic detection and feedback of the welding quality of the welding joint.

[0054] The technical features not described in the present invention can be realized by the prior art and will not be elaborated herein. The present invention is not limited to the above specific embodiments, and the changes, modifications, additions or substitutions made by those of ordinary skill in the art within the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A new method for rotary friction welding of tube plates and rod plates, characterized in that: It includes the following steps: (a) Welding part preparation stage: The material hardness of the plate to be welded is less than or equal to 20 HV of the microhardness value of the material of the tube or rod to be welded, and the thickness of the plate to be welded is greater than or equal to 3 mm; (b) Clamping stage: Fix the tube or rod to be welded on the tool holder through fastening screws, and fix the plate to be welded on the base; (c) Contact stage: After the welding surface of the tube or rod to be welded contacts the welding surface of the plate to be welded, the spindle drives the tube or rod to be welded to rotate at a high speed of 300 - 2500 r / min through the tool holder connected to it while transmitting an axial upsetting force. The plate to be welded is fixed on the base and remains stationary. The tube or rod to be welded stays at this axial position for 10 - 30 s, and the heat generated by the high-speed friction between the welding surface of the tube or rod to be welded and the welding surface of the plate to be welded plasticizes the contact surface material; (d) Penetration stage: When the contact surface material is plasticized, the tube or rod to be welded penetrates axially at a speed of 0 - 5 mm / min, and the penetration depth is less than or equal to 0.5 mm; (e) Hovering stage: After the tube or rod to be welded penetrates in place, the tube or rod to be welded continues to rotate at this axial position for 5 - 10 s to fully plasticize the contact surface material; (f) Emergency stop stage: After the hovering stage ends, the rotating tube or rod to be welded stops rotating within 1 s and continues to maintain the upsetting force of the tube or rod to be welded for 5 - 15 s; (g) Upsetting maintenance stage: After the emergency stop stage ends, continue to maintain the upsetting force of the tube or rod to be welded for 5 - 15 s; (h) Welding completion: After the upsetting maintenance stage ends, loosen the fastening screws between the tube or rod to be welded and the tool holder, lift the tool holder, and the welding is completed, finally forming a solid-phase connected welding joint to achieve the solid-phase connection between the tube and the plate or the rod and the plate; (i) Post-welding treatment: After welding is completed, remove the flash on the inner and outer sides of the welding joint of the tube or the flash on the outer side of the welding joint of the rod.

2. The new method for rotary friction welding of tube plates and rod plates according to claim 1, characterized in that: A mandrel is provided inside the tube to be welded, the mandrel is fixedly installed on the tool holder through fastening screws, the outer contour of the cross-section of the mandrel is the same as the inner contour of the tube to be welded, and the mandrel and the tube to be welded are in clearance fit with a clearance of 0.03 - 0.05 mm.

3. The new method for rotary friction welding of tube plates and rod plates according to claim 2, characterized in that: The welding surface of the rod to be welded is a plane consistent with the cross-section of the rod to be welded, or a feature body in the shape of a cone, frustum of a cone or sphere is integrally formed at the welding end of the rod to be welded. The height of the feature body is less than or equal to 0.3 mm, and the diameter of the contact position between the feature body and the welding end of the rod to be welded is less than or equal to two-thirds of the inscribed circle diameter of the cross-section of the rod to be welded.

4. The new method for rotary friction welding of tube plates and rod plates according to claim 3, characterized in that: The strength value obtained by dividing the upsetting force by the cross-sectional area of the pipe or rod to be welded is less than or equal to four-fifths of the material yield strength of the pipe or rod to be welded.

5. The novel pipe-plate and rod-plate rotary friction welding method according to claim 4, characterized in that: The roughness of the welding surfaces of the pipe, rod, and plate to be welded is Ra6.3 - Ra50; if placed in an air environment, welding shall be completed within 2 hours after the roughness treatment of the welding surface; if placed in an environment with a humidity less than 60%, welding shall be completed within 1 day after the roughness treatment of the welding surface; if placed in an inert gas environment, welding shall be completed within 30 days after the roughness treatment of the welding surface.

6. The novel pipe-plate and rod-plate rotary friction welding method according to claim 5, characterized in that: A support sleeve is sleeved outside the pipe or rod to be welded, and the support sleeve is fixedly installed on the tool shank through fastening screws. The inner contour of the cross-section of the support sleeve is the same as the outer contour of the pipe or rod to be welded. The pipe or rod to be welded and the support sleeve are in clearance fit with a fit clearance of 0.03 - 0.05 mm.

7. The novel pipe-plate and rod-plate rotary friction welding method according to claim 6, characterized in that: After welding is completed, there is a gap of 0.5 - 1 mm between the lower end surface of the support sleeve and the upper surface of the plate to be welded, and there is a gap of 0 - 0.05 mm between the lower end surface of the mandrel and the upper surface of the plate to be welded.

8. The novel pipe-plate and rod-plate rotary friction welding method according to claim 7, characterized in that: The materials of the support sleeve and the mandrel are both die steel, and the surfaces of the support sleeve and the mandrel are respectively plated with ceramic coatings.

9. The novel pipe-plate and rod-plate rotary friction welding method according to claim 8, characterized in that: During the welding process, the pipe or rod to be welded is connected to the positive or negative pole of the welding power supply, and the plate to be welded is connected to the negative or positive pole of the welding power supply. After the pipe or rod to be welded contacts the plate to be welded, power is turned on, and heat is generated through the contact resistance between the welding surface of the pipe or rod to be welded and the welding surface of the plate to be welded to assist in completing the welding; The welding power supply adopts a constant voltage control mode. During the welding process, the power-off time and the welding quality of the welded joint are determined by monitoring the current change in the circuit; when the welding current gradually increases and then stabilizes, the power supply is immediately cut off; the current value when the welding quality of the welded joint of different welding materials and welding structures is good is determined as the standard current value through tests and built into the control system in the form of a database; after welding is completed, the measured current value in the monitoring circuit is monitored and fed back to the control system of the welding device, and the control system compares the monitored current value with the standard current value of the corresponding welding materials and welding structures to achieve automatic detection and feedback of the welding quality of the welded joint.

10. The novel pipe-plate and rod-plate rotary friction welding method according to claim 9, characterized in that: The inner contour and outer contour of the cross-section of the pipe to be welded are both circular, square, rectangular, pentagonal, or hexagonal, and the cross-section of the rod to be welded is circular, square, rectangular, pentagonal, or hexagonal; The main shaft is rotatably mounted on the crossbeam, and the upper end of the main shaft is fixedly connected to the output end of the main shaft motor, and the lower end is fixedly connected to the tool holder. The two ends of the crossbeam are respectively fixed to the upper ends of the two columns, and the two columns and the base are fixed on the ground.

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