33 results about "Weld pool" patented technology

This invention provides a laser welding machine for repairing galvanized steel pipes, relating to the field of laser welding machine technology. It includes a welding station and a laser welding torch, the laser welding torch being movable on the welding station. The machine also includes a butt clamping mechanism, a welding pool, a pre-weld treatment mechanism, and a gas flow treatment mechanism. Two clamping platforms are slidably connected to the welding station, and these platforms can drive the galvanized steel pipe to rotate. The welding pool is located on the welding station between the two clamping platforms. The pre-weld treatment mechanism can perform grinding pre-treatment on the area of ​​the galvanized steel pipe to be welded. The gas flow treatment mechanism consists of clamping arm assembly one and clamping arm assembly two, rotatably connected to both sides of the pre-weld treatment mechanism. During welding, clamping arm assembly one and clamping arm assembly two can clamp the welding position of the galvanized steel pipe and use gas flow to carry away zinc vapor from the molten pool. This solves the technical problem in related technologies where zinc metal on the surface of galvanized steel pipes evaporates into zinc vapor during welding, affecting welding quality.

The application provides a welding molten pool monitoring system and method, the system comprises: an input module for obtaining a to-be-processed welding image according to a selected welding image input source; a processing module for selecting a matched welding information recognition model, inputting the to-be-processed welding image into the welding information recognition model, obtaining a welding molten pool recognition result, processing the welding molten pool recognition result by using a preset parameter algorithm to obtain a molten pool detection parameter; and an output module for pushing the molten pool detection parameter to a user. The application can obtain a to-be-processed welding image from a selected welding image input source, select a matched welding information recognition model for image recognition, process the image recognition result to obtain a molten pool detection parameter to monitor the welding effect, and has better applicability and deployment convenience.

The application provides a 650MPa-grade ultra-supercritical high-temperature steel welding electrode and a coating and deposited metal, and belongs to the field of welding materials.The raw material of the coating comprises, in weight parts, 39-43 parts of magnesia, 30-35 parts of fluorite, 3-5 parts of dolomite, 5-10 parts of ferrosilicon, 2-5 parts of sodium titanate, 10-15 parts of metallic chromium powder, 0.1-0.4 parts of chromium oxide green, 0.1-0.3 parts of aluminum-magnesium alloy and 1.5-2.5 parts of sodium alginate.Through the research on the composition of the coating, the sodium titanate and the aluminum-magnesium alloy are added to stabilize the electric arc, the electric arc has stability and concentration when high-current welding is performed, the weld pool temperature is moderate, the fluidity of the molten iron is moderate, the electric arc blowing force is stable and concentrated, and the welding operation performance is good.

This invention relates to the field of welding technology and discloses a submerged arc vertical welding method, comprising the following steps: S1, installing a forming component at the vertical butt joint gap of the workpieces to be welded to form a welding cavity; S2, extending at least two welding wires into the welding cavity and supplying welding flux into the welding cavity; S3, controlling the welding wires to ignite under the coverage of the welding flux to establish a weld pool; S4, controlling the welding wires to oscillate within the vertical butt joint gap, and controlling at least two welding wires and at least a portion of the forming component to move synchronously upward along the vertical butt joint gap. The submerged arc vertical welding method provided by this invention can achieve circumferential coverage and stable forming of the weld pool and welding flux, overcome the problem of flow and collapse caused by gravity, and achieve stable automated submerged arc welding, ensuring welding quality.

The application belongs to the field of laser welding equipment, and particularly relates to a laser welding platform for metal plates, which is aimed at the problem that the existing technology cannot adapt to different welding angles of different plates and welding pools are prone to problems, and provides a laser welding platform for metal plates, which comprises a platform main body, a support installed on the platform main body, a laser welding assembly capable of adjusting an angle installed at the upper end of the support, and a welding table matched with the welding assembly installed on the inner side of the support; the welding table is in a multi-prism structure, the plane of the edge of the welding table is used as a welding operation surface, and two welding pieces to be welded are placed on two welding operation surfaces with different angles to realize welding of the two welding pieces at different angles, so that the clamping requirements of different shapes of metal plates can be met without replacing a clamp, a heating unit is arranged between the two sets of welding tables to heat the welding pieces, welding stress is effectively reduced, internal gas is promoted to escape, and defects such as pores and cracks are avoided.

A metal inert gas arc welding process in which a multi-wire welding torch (40) is mechanized along a path to execute a predetermined weld seam on a workpiece (32, 100a, 100b, 101a, 101b), and in which a first arc (51) is generated between a first consumable wire electrode (50) and the workpiece, and a second arc (61) is generated between a second consumable wire electrode (60) and the workpiece to transfer wire electrode material into a weld pool, wherein the first wire electrode (50) is supplied by a first power source (4) and the second wire electrode (60) by a second power source (6), and at least a third wire (70) is fed directly into the weld pool, wherein the first and second wire electrodes (50, 60) and the third wire (70) are guided in the multi-wire welding torch (40) such that the wires exiting the multi-wire welding torch (40) (50, 60,70) essentially lie in a common plane (GE) and that in the common plane the first wire electrode (50) and the second wire electrode (60) form an angle of equal magnitude with opposite signs to the third wire (70), characterized in that, during the execution of the metal inert gas arc welding process, starting from a predetermined direction of movement of the multi-wire welding torch (40) to the path line, the multi-wire welding torch (40) is moved backwards on the path line without rotation of the multi-wire welding torch (40) to perform a reversal of movement, and with the beginning of the backward movement of the multi-wire welding torch (40), the third wire (70) is initially not fed into the weld pool, and thereafter, in a transition phase, a current source (5) of the third wire (70) is supplied starting from a predetermined initial operating value of at least one process parameter current,Voltage and feed rate are controlled to a predetermined steady-state operating value of at least one process parameter.

This invention relates to the field of gas-electric vertical welding technology, specifically disclosing a three-wire gas-electric vertical welding method, comprising: setting a butt joint between a first welded component and a second welded component; sealing the rear side of the butt joint; sequentially placing a first welding wire, a second welding wire, and a third welding wire from back to front in the butt joint, wherein the first welding wire and the third welding wire are respectively connected to a welding power source, and the second welding wire is not connected to a welding power source; controlling the first welding wire, the second welding wire, and the third welding wire to synchronously and periodically oscillate in the front-back direction and move upward synchronously to form a weld pool in the butt joint; controlling the wire feeding speed of the second welding wire to increase from zero to adjust the temperature of the weld pool, so that the second welding wire reaches a fusion equilibrium state. The three-wire gas-electric vertical welding method of this invention eliminates the need for beveling, avoids excessively high temperatures in the central area of ​​the weld pool, and thus improves the mechanical properties of the weld.

This application relates to a method for producing a weld blank (1), comprising: providing two pre-coated plates (2), butt-welding the pre-coated plates (2) using filler wire, wherein during butt welding, a pre-coated layer (5) completely covers at least one face (4) of each plate (2), the filler wire (20) having a carbon content of 0.01% to 0.45% by weight, and the composition of the filler wire (20) and the proportion of filler wire (20) added to the weld pool are selected such that the weld joint (22) has (a) a quenching factor FT. WJ FT WJ -0.9FT BM ≥0, where: FT BM The quenching factor of the least hardenable matrix (3), and FT WJ and FT BM The value is determined to be: FT = 128 + 1553xC + 55xMn + 267xSi + 49xNi + 5xCr - 79xAl - 2xNi 2 -1532xC 2 -5xMn 2 -127xSi 2 -40xCxNi-4xNixMn, and (b) carbon content C WJ <0.15% by weight, or if C WJ ≥0.15% by weight, then the softening factor FA WJ Make FA WJ >5000, where FA = 10291 + 4384.1xMo + 3676.9Si - 522.64xAl - 2221.2xCr - 118.11xNi - 1565.1xC - 246.67xMn. This application also relates to welded steel billets and steel components formed by welding, hot pressing, and cooling.

The application discloses underwater laser welding torch, including laser head and drain cover, laser head includes sealed shell, laser head body, welding mechanism and pressure balance mechanism, one end of the sealed shell is detachably connected with the drain cover, the laser head body is arranged at one end of the sealed shell away from the drain cover and extends into the sealed shell, the welding mechanism is arranged in the laser head body, and the pressure balance mechanism is used for balancing pressure on both sides of the sealed shell. The underwater laser welding torch can guarantee the sealing property of the torch structure under water through the arrangement of the pressure balance mechanism and the drain cover, the local dry method environment jointly created can realize stable forming under the environment of several meters of water depth, the influence of deep water pressure on the drainage effect and the dry method environment is effectively overcome, the requirements of no water and pure argon protection in the weld area are realized, underwater laser welding can be stably and reliably carried out, the welding pool can be better protected, and the weld forming is good.

This invention discloses a special welding equipment for automotive insulation connecting pipes, belonging to the field of specialized welding technology. It includes a main frame and a positioning mechanism for vertically positioning the insulation pipe end and flange during welding. The main frame is equipped with a clamping mechanism for feeding and clamping the insulation pipe end and flange to be welded, and two welding mechanisms for welding the insulation pipe end and flange. The invention features side-sealed doors on both sides of the welding box, with automatic opening and closing achieved through a linkage mechanism between a movable seat and an inward-opening door frame. When the welding torch enters the welding station, the side-sealed doors automatically close, isolating the welding area from the external environment, effectively reducing spatter, fumes, and arc light leakage, improving operational safety, and preventing external airflow from interfering with the weld pool, ensuring weld quality. After welding is completed, the side-sealed doors automatically open as the movable seat retracts, achieving fully automated control of the entire process.

A laser-arc hybrid welding apparatus includes: a laser welding unit comprising a laser beam; an arc welding unit comprising an arc welding torch; a gas shroud comprising an annular inner shell, an annular outer shell, an inner space, and an outer space; and an annular gas supply pipe comprising a protective gas inlet and a plurality of gas blowing holes, the opening direction of the plurality of gas blowing holes facing the workpiece; the laser beam passes through the inner space and is directed toward the workpiece, and the arc welding torch passes through the inner space and is directed toward the workpiece; a nozzle with a gradually decreasing size is formed at one end of the annular inner shell facing the workpiece, and the nozzle protrudes beyond the annular outer shell along the central axis; and the outer space includes an exhaust gas inlet and an exhaust gas outlet, the exhaust gas inlet being adjacent to the nozzle. Accordingly, it has the effects of protecting the weld pool, reducing insufficient weld depth or unstable weld bead, and preventing interference between the workpiece and the tip of the welding torch.

This invention discloses an Al-Cu welding wire, its preparation method, and its application, belonging to the field of laser welding technology. The welding wire is prepared by weighing various components, including aluminum, aluminum-copper master alloy, aluminum-titanium master alloy, aluminum-magnesium master alloy, aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-scandium master alloy, and aluminum-zirconium master alloy, according to a designed welding wire composition ratio. These components are then melted and cast to obtain an ingot. The ingot undergoes multi-stage homogenization treatment, followed by hot rolling and wire cutting. This invention improves the proportion of isometric regions in the weld microstructure by introducing trace amounts of Sc, Si, Ti, and Zr into a low-cost, high-Cu content weld pool system, refining the weld microstructure and enhancing mechanical properties compatible with Al-Cu-Li alloys. Furthermore, by reducing the content of the hard and brittle W phase through appropriate processes, the invention effectively ensures the machinability of the welding wire and the weld performance.

This invention belongs to the field of image data processing technology, specifically relating to a method and system for monitoring the quality of laser welding of aluminum single-panel panels. The method includes: extracting the centroid displacement of the weld pool in the aluminum single-panel welding process and denoising it to obtain an oscillation velocity sequence; constructing a state vector through phase space reconstruction and calculating the trajectory deformation degree accordingly; calculating the maximum distortion threshold by combining real-time laser power, welding speed, and duration; comparing the trajectory deformation degree with the threshold, and determining instability and cutting off the laser if the threshold is exceeded. This invention utilizes the geometric characteristics of the phase space trajectory to monitor the dynamic behavior of the weld pool and introduces a dynamic compensation mechanism for accumulated enthalpy, effectively distinguishing between natural thermal fluctuations and abnormal instability, thus achieving precise monitoring and control of welding quality.

The invention discloses a laser filler wire welding method for a high-martensite-content ultrahigh-strength stainless steel joint, welding flux and a laser welding part. Specifically, two stainless steel blank workpieces are provided to form an assembly, and filler wires are used for melting the blank assembly and welding flux under the action of a laser heat source to form a welding joint. The filler welding wire comprises elements such as C, Mn and Si, and the filler welding wire comprises, by weight, 0.01% < = C < = 0.45%, 0.5% < = Mn < = 3.0%, 0.1% < = Si < = 2.0%, 10% < = Cr, 5% < = Ni, 5% < = Mo and the balance Fe and inevitable impurities. The components of the filler wire and the specific proportion of the filler wire added into the welding pool enable the welded joint to meet the conditions that the martensite content in the welded joint is not lower than 80%, and the average microhardness of a melting zone of the welded joint is not lower than 300 HV. The welding joint has ultrahigh strength, and the strength of the welding joint can reach 80% or above of the strength of a base material at the room temperature and the high temperature (100 DEG C); and the application in environments with different assembly gaps can be met.

This invention relates to the field of industrial artificial intelligence technology, and discloses a method for constructing a welding process control model, a welding process control method, and an apparatus. The method for constructing the welding process control model includes: constructing a triplet training dataset containing multimodal inputs, physical reasoning thought chain text, and strategic intent; based on the training dataset, supervising fine-tuning a pre-trained visual-language-action large model to obtain a fine-tuned large model; constructing positive and negative sample reasoning path pairs, and using a direct preference optimization algorithm to perform preference alignment training on the fine-tuned large model to obtain the welding process control model. This invention performs supervised fine-tuning and preference alignment training on the visual-language-action large model, enabling the model to possess a deep physical cognition ability of the dynamic behavior of the weld pool. It can generate thought chain text containing phenomenon observation, physical attribution, and strategic intent based on multimodal perception information, thereby realizing the understanding of the physical state of the welding process and causal reasoning of the causes of defects.

This invention provides a Hastelloy pipe welding method. Before welding, degreasing is performed using sulfur-free acetone or ethanol. High-purity argon gas is used during welding. A large angle and small blunt edge are selected for the bevel. Welding is performed using low welding heat input, a short arc, and minimal or no oscillation. This invention effectively prevents the addition of carbon, oxygen, and hydrogen to the weld, thus preventing porosity and cracks and reducing the mechanical properties of the weld metal. It reduces the number and probability of porosity caused by harmful gases. It effectively addresses the poor fluidity and wettability of the weld pool and shallow penetration of nickel-based alloys, which easily lead to defects such as incomplete fusion and incomplete penetration. It effectively prevents defects such as incomplete fusion and inclusions caused by the high melting point of the oxide layer on the surface of nickel-based alloys. It prevents impurities such as sulfur, phosphorus, and carbon from entering the weld and forming welding hot cracks. It improves the utilization rate of expensive nickel-based alloy materials. It reduces labor time and improves welding efficiency and quality.

A method for laser welding bipolar plates includes laser welding two at least partly overlapping joining partners along a specified welding path in order to produce an overlapping connection between the two joining partners, during the laser welding, observing whether, following a process zone, at least one undulating structure forms in a weld pool, based on the observing, initiating a measure for preventing or handling an incomplete connection of the two joining partners along at least one section of the welding path.

The application discloses a kind of multifunctional clamps of welding pool online monitoring platform, belong to welding production line clamp technical field, this multifunctional clamp includes protective cover, installation seat is equipped in protective cover, monitoring component is equipped on installation seat, monitoring component can be rotated relative to installation seat, independent monitoring structure is equipped in protective cover, independent monitoring structure is separately adjusted the monitoring angle of any one sensor in monitoring component, synchronous monitoring structure is equipped in protective cover, and the monitoring angle of all sensors in monitoring component is synchronously adjusted by synchronous monitoring structure.The application is adjusted by independent monitoring structure for the monitoring angle of laser tracking sensor, pool monitoring sensor and workpiece temperature detection sensor alone, and the monitoring angle of laser tracking sensor, pool monitoring sensor and workpiece temperature detection sensor is adjusted by synchronous monitoring structure simultaneously driven.

This invention provides a laser-induced longitudinal dual-arc composite flexible heat source method for high-efficiency welding of thick plates with narrow gaps. It employs a laser, a wire feeder, and two independent welding power sources. The two arc welding torches and the laser beam are positioned (or not) within the same vertical welding plane, maintaining a certain angle and distributed one in front of the other on the same side of the laser beam; the welding wire is distributed on the other side of the laser beam. The angles and distances between each heat source can be adjusted individually. This spatial arrangement of heat sources improves the accessibility and stability of welding thick plates with narrow gaps. Before welding, the spatial angles and distances between the two arc welding torches, the laser beam, and the welding wire are adjusted; during welding, welding parameters are adjusted to control the coupled plasma energy density within the narrow gap space, allowing for real-time control of the molten droplet transfer behavior and weld pool flow characteristics. Compared to traditional arc welding, this invention can achieve an energy density of 10... 3 W•cm ‑2 ~10 6 W•cm ‑2 It is flexible and adjustable, with a welding deposition rate of 3.67 kg / h, increasing the deposition efficiency by more than 15 times.

A weld quality inspection system for indicating a quality of a weld during a welding process on at least one work piece. The weld quality inspection system includes an infrared camera configured to provide visual data of a weld pool. A microphone is configured to provide audio data of an arc of a welder. At least one operational technology (OT) data source is configured to provide OT data. A controller is configured to receive the visual data, the sound data and the OT data to determine if conditions associated with a bad weld are met and to provide feedback to an operator or robot in response to a detection that the conditions are met.

The utility model discloses an explosion -proof gas protection device of hydrogen fuel tank laser welding, including the welding head body, the bottom fixed mounting of welding head body has the light -passing circle, the side of light -passing circle is provided with the gas pipe joint, the bottom of light -passing circle is provided with the air jet mouth, the middle part sealed rotation of light -passing circle is connected with the rotating circle, the outer periphery of light -passing circle fixed mounting has the circular slide rail in the rotating circle upside and downside, the circular slide rail top fixed mounting of upper portion has the regulating motor, the opposite side sliding connection of two circular slide rails has the moving block, the top fixed mounting of upper portion moving block has the gear ring, the output of regulating motor fixed mounting has the gear. Can form the better protection gas atmosphere in the weld pool area and the uncooled area after the solidification of molten pool, forms the effective gas protection to the whole welding process of laser welding weld, thereby has improved the quality of weld.

A method for laser-welding at least two conductor pieces includes providing an elongated first conductor piece having a first end portion and a first end face, and providing an elongated second conductor piece having a second end portion and a second end face. The first end face is arranged adjacent to the second end face. The method further includes producing a first laser spot on the first end face to produce a first weld pool, and producing a second laser spot on the second end face to produce a second weld pool. The first laser spot and the second laser spot are produced simultaneously. The first weld pool and the second weld pool subsequently merge to form a common weld pool.

The present invention provides an oscillating laser-submerged arc hybrid welding method for single—sided welding and double-sided forming of medium-thick plates and a device. By combining the high penetration capability of a ten-kilowatt—class laser heat source with the high deposition efficiency of a submerged arc heat source, efficient and high—quality welding of medium—thick plates can be achieved. The welding method specifically includes the steps of: employing a Y-shaped groove on butt joint faces of two plates to be welded; positioning the oscillating laser heat source in front along a welding direction, followed by the submerged are heat source behind, with both heat sources aligned on the same straight line and sharing a common weld pool; and melting a submerged arc welding wire into the weld pool under the joint action of the oscillating laser heat source and the submerged are heat source during welding, and welding a singlesided groove. FIG. 1

The application discloses a kind of aluminum alloy variable polarity TIG deep penetration welding penetration prediction method and system, comprising: collecting welding pool image, input pre-trained type convolutional neural network to carry out pool state identification;If it is positive polarity stage, then the image is input to pre-trained semantic segmentation type convolutional neural network, the shadow area caused by pool area and small hole is marked, and the segmentation result image is obtained;Approximate depth of pool width and small hole is calculated based on the segmentation result image;The pool width and the approximate depth of small hole are input into the pre-trained integrated learning prediction model to predict the current penetration;The system includes image acquisition device, pool state identification module, feature region segmentation module, feature size calculation module and penetration prediction module;The application can realize the real-time prediction of aluminum alloy blind hole type deep penetration welding weld penetration, and provide support for energy control and process optimization of welding process.

The present invention discloses a segmented welding method for aero-engine welding components. Specifically, the method involves determining a model, including: fabricating a test piece, obtaining original welding parameters, arbitrarily selecting a weld point P0 on the weld, determining a first volume V0, and selecting a weld point Px on the weld with a thickness T. X Take the J1*T in front of the weld pool of the Px solder joint. X The length of the first volume V0 is used to determine the second volume Vx, and the model is determined based on the second volume Vx and the first volume V0. The initial weld point Pz0 and the adjacent weld point Pz1 of the weld seam of the part are determined. The original parameters and mathematical model obtained by the test piece are used to determine the welding voltage, current and speed. The first and second parameters are input into the programming software to control the CNC welding machine to complete the welding between the parts. It can ensure the consistency of weld formation and improve the welding quality under the condition of changes in weld cross-section and thickness.

This application relates to a method for producing a weld blank (1), comprising: providing two pre-coated plates (2), butt-welding the pre-coated plates (2) using filler wire, wherein during butt welding, a pre-coated layer (5) completely covers at least one face (4) of each plate (2), the filler wire (20) having a carbon content of 0.01% to 0.45% by weight, and the composition of the filler wire (20) and the proportion of filler wire (20) added to the weld pool are selected such that the weld joint (22) has (a) a quenching factor FT. WJ FT WJ -0.9FT BM ≥0, where: FT BM The quenching factor of the least hardenable matrix (3), and FT WJ and FT BM The value is determined to be: FT = 128 + 1553xC + 55xMn + 267xSi + 49xNi + 5xCr - 79xAl - 2xNi 2 -1532xC 2 -5xMn 2 -127xSi 2 -40xCxNi-4xNixMn, and (b) carbon content C WJ <0.15% by weight, or, if C WJ ≥0.15% by weight, then the softening factor FA WJ Make FA WJ >5000, where FA=10291+4384.1xMo+3676.9Si-522.64xAl-2221.2xCr-118.11xNi-1565.1xC-246.67xMn. This application also relates to welded steel billets and steel components formed by welding, hot pressing and cooling.

A device for use with welding systems and processes, comprising an encapsulating apparatus configured to encapsulate a welding torch nozzle at the tip thereof, wherein the apparatus includes an upper body portion which mounts on the nozzle; and a lower body portion which extends beyond the tip of the nozzle toward a work surface; and wherein during a welding process the apparatus encapsulates a welding electrode passing through the tip of the nozzle, an arc generated by the welding torch, and a weld pool surface directly above the work surface during deposition of the weld pool, and wherein the encapsulating apparatus prevents atmospheric gases from entering the weld pool during the welding process and reduces the shielding gas requirements compared to current gas shielded torch apparatuses, and wherein derivatives of the lower body portion are configured to accommodate unique welding grooves, joint designs, and DED additive manufacturing work piece geometries.

The present application relates to a kind of multi-path powder feeding wire and powder coupling MIG welding device and method, belong to welding technical field.Water level electric ball screw guide rail is connected with single-axis motion controller, and the control of linear motion of water level electric ball screw guide rail is realized by single-axis motion controller;Work platform is fixedly connected with water level electric ball screw guide rail, pressing plate is fixedly connected with work platform, and the fixation of welding workpiece is realized by the compression fixation function of pressing plate;Clamp connecting plate is fixedly connected with vertical electric ball screw guide rail, and used to support the weight of entire welding torch structure.Coaxial multi-channel mode is used to uniformly deliver alloy powder material to welding pool, so that powder material and wire material are melted and deposited in welding pool under the action of arc, and the effect of coupling is achieved.The composite process proposed in the present application greatly increases the space for improving welding structure performance.Protective gas support cover is provided, so that MIG welding device can smoothly carry out welding operation outdoors.

Title: Welding Device Comprising a Contamination Guard. Welding device (1) arranged to perform welding between at least two parts to be welded (2), the welding device comprising: a welding unit (3) arranged to perform welding along the junction (4) of two parts to be welded, generating a weld pool (5) at a weld zone (10); a contamination guard (6) arranged to be placed, in particular movable, in contact with the parts to be welded (2) such that the welding unit (3) and the contamination guard (6) encompass the entire weld pool (5) and that any half-line (7) extending from the weld pool intersects either the contamination guard or the welding unit, the welding device (1) being arranged in particular to move the weld zone (10) relative to the parts to be welded during welding. Figure for the abstract: Fig. 1

The application discloses a back protection tool for deep penetration welding of a low-temperature liquid tank container cylinder, which comprises a back gas protection assembly arranged at a welding pool position on the back of a butt joint welding seam of the cylinder, wherein the back gas protection assembly comprises a bladeless fan, a ring-shaped air guide chamber butted on a ring-shaped air outlet on the front end of the bladeless fan, an air inlet box sleeved on the outer circle of the handle part of the bladeless fan and used for surrounding the air inlet on the outer circle of the handle part of the bladeless fan, and a rear end sealing baffle arranged at the rear end of the bladeless fan and used for sealing the rear part of the hollow part of the bladeless fan; the rear end sealing baffle is connected with a first protection gas supply pipe which is communicated with the hollow part of the bladeless fan; the air inlet box is connected with a second protection gas supply pipe which is communicated with the inside of the air inlet box; and the ring-shaped air guide chamber is provided with a ring-shaped air guide opening, and the protection gas direction of the ring-shaped air guide opening is towards the back of the welding pool. The application improves the welding stability and the welding seam quality of the deep penetration argon arc welding.