Plasma welder for construction work

Abstract

The application relates to a plasma welding machine for construction engineering, which comprises a rack, two supporting units are arranged on the rack at intervals, clamping and positioning mechanisms are arranged on the supporting units to clamp two to-be-welded profile steels, and a rotary welding mechanism is arranged between the two supporting units and is sleeved on the outside of the butt joint of the profile steels. The rotary welding mechanism comprises a C-shaped frame which is rotationally assembled on the rack and has lateral openings in the circumferences, and a rotary driving mechanism which drives the C-shaped frame to rotate at intervals. A guide frame is fixed in the C-shaped frame, a sliding block is slidably arranged on the guide frame, the sliding block is driven by a welding stroke driving mechanism to reciprocate and carries a welding head. After the C-shaped frame is rotated to make the sliding block parallel to one side surface of the profile steel, the welding head carries out linear guide welding. The mechanical rigidity is greatly improved, and the problems of trajectory instability and jamming during the profile steel circumferential welding are solved.

Description

Technical Field

[0001] This invention relates to the field of welding technology for building profiles, and specifically to a plasma welding machine for building engineering. Background Technology

[0002] In modern building engineering and bridge construction, with the increasing number of high-rise buildings and large-span spatial structures, rectangular steel sections are widely used as core load-bearing components. These steel sections typically need to be segmented and joined on the ground or in a prefabrication yard, and the circumferential all-position welding of the joints is a crucial process step to ensure the overall tensile and shear strength of the steel structure.

[0003] Traditional welding methods rely on manual operation of hand-held welding torches, which not only requires a high level of skill from the welder, but also easily produces welding defects such as slag inclusions, incomplete fusion, or porosity when facing welding dead corners such as the bottom and back sides of the steel profile, affecting construction efficiency and increasing quality and safety risks.

[0004] A welding device for building construction disclosed in Chinese invention patent document CN118060816A uses a notched collar and a notched toothed ring fitted on the outer wall of a steel profile. The notched toothed ring is driven to rotate continuously within the collar by a transmission mechanism, thereby driving the welding head installed on it to perform 360° circumferential welding around the joint of the steel profile.

[0005] However, when this type of continuous rotary welding equipment is applied to rectangular steel sections with large length-to-width ratios in building construction, significant structural limitations are revealed:

[0006] Because rectangular steel sections have geometric symmetry and varying lengths and widths, if a fully enclosed or notched 360° continuous rotation structure is used, the distance between the spatial radius of rotation and the steel surface is prone to periodic fluctuations when the welding head rotates to different side lengths and rounded transition sections, thus affecting the energy density of the plasma arc. Furthermore, to adapt to dimensional changes, passive compensation often relies on complex long-stroke springs and return slip ring mechanisms; however, long-stroke springs lead to structural instability and poor welding accuracy. Summary of the Invention

[0007] The purpose of this invention is to provide a plasma welding machine for construction engineering, which solves the technical problems of structural instability and poor welding accuracy of existing welding devices for profiles with different aspect ratios.

[0008] The technical solution of the present invention is as follows:

[0009] A plasma welding machine for construction engineering includes:

[0010] frame;

[0011] Two support units are arranged horizontally at intervals on the frame to support two steel sections to be welded.

[0012] Clamping and positioning mechanisms are respectively installed on the support unit for clamping and releasing the steel profiles;

[0013] A rotary welding mechanism, positioned between two support units and fitted over the outside of the butt joint of the two steel sections, includes:

[0014] The C-shaped frame is rotatably mounted on the machine frame and has circumferential openings for radial insertion and removal of steel profiles;

[0015] A rotary drive mechanism is arranged between the C-frame and the support unit to drive the C-frame to rotate intermittently at a fixed angle around the circumference;

[0016] The guide frame is fixed inside the C-frame;

[0017] The slider and guide slide are mounted on the guide frame;

[0018] The welding stroke drive mechanism is connected between the guide frame and the slider, driving the slider to reciprocate on the guide frame;

[0019] The welding head is mounted on the slider, with its end facing the butt joint of the steel section;

[0020] After the rotary drive mechanism drives the C-frame to rotate intermittently by a set angle so that the sliding direction of the slider is parallel to the butt joint on one side surface of the steel section, the welding stroke drive mechanism drives the welding head to move so that the welding head welds the butt joint on that side.

[0021] Furthermore, the circumferential extension arc of the C-frame and the guide edge is not less than 270 degrees;

[0022] The rotary drive mechanism includes an external gear ring fixed to the outer circumferential surface of the C-frame, and a drive gear rotatably mounted on the frame or support unit and meshing with the external gear ring. It also includes a rotary servo motor that drives the C-frame to rotate intermittently in a first direction and continuously in a second direction, wherein the first direction and the second direction are arranged in opposite directions.

[0023] Furthermore, the cross-section of the steel profile is rectangular, and in the first direction, the rotary servo motor drives the C-shaped frame to rotate intermittently along a step of 90°.

[0024] Furthermore, the outer wall of the C-shaped frame is provided with a guide edge extending in a C-shape, and the support unit is provided with a semi-circular guide groove for sliding engagement of the guide edge.

[0025] Furthermore, each of the support units includes an outer support seat and an inner support seat arranged at intervals along the extension direction of the steel section, the rotary welding mechanism is disposed between the two inner support seats, and the C-shaped frame is rotatably assembled on the inner support seat.

[0026] Furthermore, it also includes a vertical compensation component, which is disposed between the slider and the welding head, and is used to adjust the distance between the welding head and the surface of the steel section in a direction perpendicular to the surface of the steel section.

[0027] Furthermore, the vertical compensation component includes a vertical slide rail fixed to the slider, a vertical slide plate that slides with the vertical slide rail, and a compensation screw and nut pair and a compensation servo motor for driving the vertical slide plate to rise and fall. The welding head is mounted on the vertical slide plate. The welding machine also includes a controller and a distance sensor arranged on the welding head. The controller is connected to the distance sensor for sampling and to the compensation servo motor for control, so as to adjust the distance between the end of the welding head and the surface of the weld seam in real time after detecting the distance signal of the distance sensor.

[0028] Furthermore, the welding head includes a rear base rotatably mounted on the vertical slide plate, a semi-gear ring fixed to the outside of the rear base, and an active yaw motor mounted on the vertical slide plate for driving the semi-gear ring to rotate. The welding head is mounted on the rear base, and the controller is connected to the active yaw motor to adjust the orientation of the welding head to be in the same direction as the normal of the rounded corner when passing through the rounded corner path of the profile.

[0029] Furthermore, the welding stroke drive mechanism includes a transverse lead screw mounted on a guide frame and a feed motor that drives the transverse lead screw to rotate, with the slider threadedly connected to the transverse lead screw.

[0030] Furthermore, the clamping and positioning mechanism includes two grippers symmetrically arranged perpendicular to the extension direction of the steel section, and a two-way lead screw or two-way cylinder for driving the two grippers to move towards or away from each other.

[0031] The beneficial effects of this application are: two support units and a clamping and positioning mechanism are arranged at intervals on the frame, a C-shaped frame is rotatably assembled on the frame and has a circumferential opening for radial insertion and removal of steel profiles, and a guide frame, a slider and a welding stroke drive mechanism are installed inside the C-shaped frame.

[0032] The C-frame design with openings allows long strips of steel to be welded to be placed directly into the welding station from the radial direction, improving the convenience of on-site installation and disassembly.

[0033] The rotary drive mechanism drives the C-shaped frame to rotate intermittently at a fixed angle, which in turn drives the slider to move back and forth in a linear motion. In the actual welding process, it is not necessary to perform a continuous 360-degree full-circle rotation. Only a few intermittent rotations are needed to achieve full welding of the entire surface of the rectangular steel section in conjunction with the linear reciprocating motion.

[0034] The combination of intermittent fixed-angle indexing and linear reciprocating welding eliminates the risk of accumulated mechanical springback and jamming during dynamic motion. It ensures absolute operational stability under conditions of intense heat radiation and splashing, enabling efficient, high-precision, all-position automated welding of complex irregular cross-section steel structures, demonstrating outstanding substantive features and significant progress.

[0035] Furthermore, it can achieve integral welding of butt joints for steel sections with different aspect ratios, or even large aspect ratios. It is easy to adjust, has a simple structure, and is highly versatile. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a specific embodiment of a plasma welding machine for construction engineering according to the present invention.

[0037] Figure 2 for Figure 1 Schematic diagram of the structure of the Chinese and foreign support bases;

[0038] Figure 3 for Figure 1 Assembly diagram of the inner support base and the C-frame;

[0039] Figure 4 for Figure 3 Another perspective illustration;

[0040] Figure 5 for Figure 4 A cross-sectional view of the C-frame;

[0041] Figure 6 for Figure 4 Longitudinal sectional view of the C-frame;

[0042] Figure 7 for Figure 6 Enlarged view of a portion of point A in the middle;

[0043] Figure 8 for Figure 5 Welding posture diagram of the welding joint on the arc path;

[0044] Figure 9 for Figure 5 Welding posture diagram of the welding joint to the first facade;

[0045] In the diagram: 1-Frame; 11-Steel section; 12-Butt joint;

[0046] 2-Outer support base; 21-Double-direction lead screw; 22-Gripper; 23-Clamping motor;

[0047] 3-Inner support seat; 31-Semi-circular guide groove;

[0048] 4-C-frame; 41-Opening; 42-External gear ring; 43-Guide edge;

[0049] 5 - Rotary servo motor; 51 - Drive gear;

[0050] 6-Guide frame; 61-Transverse linear guide rail; 62-Slider;

[0051] 7-Horizontal lead screw; 71-Feed motor;

[0052] 8-Welding head; 81-Rear base; 811-Half gear ring; 82-Distance sensor;

[0053] 9-Vertical slide rail; 91-Vertical slide plate; 92-Compensating lead screw and nut pair; 93-Compensating servo motor;

[0054] 10 - Active yaw motor. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0056] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0057] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0059] A specific embodiment of the plasma welding machine for construction engineering of the present invention: as follows Figures 1 to 9 As shown, the machine includes a frame 1, on which two sets of support units are arranged at intervals along the horizontal extension direction of the steel section 11. The two sets of support units respectively support two steel sections 11 to be connected located on both sides of the butt joint 12 gap.

[0060] The support unit includes an outer support seat 2 and an inner support seat 3 arranged at intervals along the extension direction of the steel section 11. The outer support seat 2 and the inner support seat 3 form a two-point support array, which can effectively counteract the bending moment generated by the steel section 11 in the cantilever state and ensure that the two steel sections 11 at the joint 12 are in a coaxial state.

[0061] Each support unit is equipped with a clamping and positioning mechanism for clamping and releasing the steel profile 11. This clamping and positioning mechanism specifically consists of two grippers 22 symmetrically arranged axially perpendicular to the steel profile 11, a bidirectional lead screw 21 that drives the two grippers 22 to move synchronously towards or away from each other, and a clamping motor 23. Alternatively, a bidirectional cylinder can be used to directly drive the relative movement of the grippers 22.

[0062] After the steel section 11 to be welded is hoisted and placed on the outer support 2 and the inner support 3, the control system outputs a clamping signal to the clamping motor 23 of the bidirectional lead screw 21. The two grippers 22 move closer together until they abut against the side wall of the steel section 11. This achieves automatic alignment and centering. After the welding process is completed, the mechanism is reversed to quickly release the grippers 22 and enter the next work cycle. The entire clamping and releasing process requires no manual intervention, improving the efficiency of on-site construction.

[0063] A rotary welding mechanism is suspended between the two support units. Specifically, it is arranged between the two inner support seats 3 and sleeved on the outside of the butt joint 12 of the two steel sections 11. The rotary welding mechanism includes a C-shaped frame 4 that is rotatably mounted on the inner support seat 3. The C-shaped frame 4 has an opening 41 in its circumference with a width greater than the maximum diagonal dimension of the steel section 11 to be welded. The opening 41 can be radially inserted into or removed from the working area where the butt joint 12 is located from the side of the steel section 11.

[0064] The outer wall of the C-frame 4 has an integrally formed or high-strengthly bolted guide edge 43 extending in a C-shape along its arc trajectory. The inner support base 3 is provided with a semi-circular guide groove 31 for the guide edge 43 to be inserted and slidably fitted. In order to prevent the C-frame 4 with the opening 41 from derailing or losing its center of gravity during rotation because the opening 41 crosses the semi-circular guide groove 31, the circumferential extension arc of the solid frame of the C-frame 4 and the guide edge 43 is not less than 270 degrees, so that the guide edge 43 always has an effective arc length of more than 180 degrees covering the constraint range of the semi-circular guide groove 31.

[0065] Between the C-frame 4 and the support unit, a rotary drive mechanism is arranged to provide rotational power for the C-frame 4. The rotary drive mechanism includes a high-precision external gear ring 42 fixed on the outer circumferential surface of the C-frame 4, a drive gear 51 rotatably mounted on the inner support seat 3 and located on the bottom side of the external gear ring 42 and meshing with the external gear ring 42 with no backlash, and a rotary servo motor 5 that is driven in conjunction with the drive gear 51.

[0066] The rotary servo motor 5 is programmed to drive the C-shaped frame 4 to rotate intermittently with high-frequency start and stop along a first direction, and to rotate continuously and uniformly along a second direction arranged in the opposite direction to the first direction. When performing full butt welding on the steel section 11 with a rectangular or square cross-section, the rotary servo motor 5 drives the C-shaped frame 4 to rotate intermittently in 90-degree step steps.

[0067] A guide frame 6 is fixedly installed in the internal cavity of the C-frame 4. The guide frame 6 includes a transverse linear guide rail 61 that is parallel to and fixed inside the C-frame 4. A slider 62, which carries the welding tool, is guided and slidably mounted on the guide frame 6. The slider 62 is guided and engaged with the transverse linear guide rail 61. A welding stroke drive mechanism is also connected between the guide frame 6 and the slider 62. This mechanism mainly includes a transverse lead screw that is parallel to the transverse linear guide rail 61, and a feed motor 71 installed at one end of the C-frame 4 to drive the transverse lead screw to rotate at high speed. When the feed motor 71 receives a pulse command to drive the transverse lead screw to rotate, the slider 62 is driven to make extremely smooth linear reciprocating movements on the guide frame 6 through the motion conversion of the threaded pair.

[0068] A plasma welding head 8 is mounted on the slider 62, with the end of its plasma arc compression nozzle pointing towards the location of the butt joint 12 of the steel section 11.

[0069] In the initial welding state, the rotary servo motor 5 positions the C-frame 4 at a specific spatial angle. At this time, the axis of the transverse lead screw fixed inside the C-frame 4 is adjusted to be parallel to the butt joint 12 on the upper surface of the steel profile 11. As the system issues an arc-starting command, the plasma welding head 8 establishes a stable penetrating molten pool. Simultaneously, the feed motor 71 starts, driving the transverse lead screw to rotate at a uniform speed. The slider 62 carries the plasma welding head 8 along a straight trajectory parallel to the top surface of the steel profile 11, guiding and sliding. During this process, it is a one-dimensional linear feed, shielding the mechanical jitter and algorithm delay caused by any spatial curve interpolation. The plasma welding head 8 welds through the butt joint 12 on the top surface of the steel profile 11 with an extremely stable speed and posture until it reaches the starting point of the edge rounded corner on that side.

[0070] At this moment, the linear feed motor 71 pauses, and the rotary servo motor 5 of the rotary drive mechanism starts instantly, driving the C-shaped frame 4 to rotate precisely 90 degrees sequentially along the first direction with extremely high angular acceleration. After this instantaneous fixed-angle intermittent rotation is completed, the axes of the guide frame 6 and the transverse lead screw rotate with the space of the C-shaped frame 4, switching to the first side elevation parallel to the steel profile 11. Subsequently, the feed motor 71 reverses and moves back to the initial position for welding, or welds are performed during the direct reverse movement.

[0071] Similarly, after the welding stroke drive mechanism completes the straight-line welding of one side, the rotary drive mechanism drives the C-shaped frame 4 to rotate intermittently by a set angle, i.e., 90 degrees, so that the sliding direction of the slider 62 is parallel to the next side, i.e., the bottom surface, of the steel section 11, and straight-line welding is performed again until the final 90-degree rotation completes the welding of the second side. This dynamic and static combination of the rotary drive mechanism driving the C-shaped frame 4 to rotate intermittently by a set angle of 90 degrees and the welding stroke drive mechanism driving the welding head 8 to move linearly can achieve high-quality full welding of all surfaces of the rectangular steel section 11 through just three basic intermittent rotations.

[0072] In actual steel structure construction sites, due to inherent manufacturing tolerances in the steel rolling process, slight distortion caused by long-distance transportation of the steel section 11, and the intense thermal expansion and contraction and thermal deformation generated during plasma penetration welding, the actual surface of the steel section 11 often deviates from its theoretical height, exhibiting local unevenness at the millimeter or even centimeter level. To overcome these defects, a vertical compensation component is provided between the slider 62 and the welding head 8. This component is used to dynamically adjust the distance between the welding head 8 and the surface of the steel section 11 in real time along a direction perpendicular to the current surface of the steel section 11. Specifically, the vertical compensation component includes a vertical slide rail 9 vertically mounted on the slider 62, a vertical slide plate 91 that slides with the vertical slide rail 9, and a compensation screw nut pair and a compensation servo motor 93 for driving the vertical slide plate 91 to rise and fall. The welding head 8 is mounted on the vertical slide plate 91.

[0073] A non-contact distance sensor 82 is arranged on the plasma welding head 8. The system is also equipped with a controller, which is connected to the distance sensor 82 for real-time sampling and simultaneously controlled by a compensation servo motor 93. During the transverse linear scanning welding process of the plasma welding head 8 along the surface of the steel section 11, the distance sensor 82 measures the actual physical distance between the end of the welding head 8 and the weld surface at an extremely high frequency, and feeds back this distance analog or digital signal to the controller in real time. The controller outputs pulse commands to instruct the compensation servo motor 93 to rotate, driving the compensation screw nut pair to move the vertical slide plate 91 and the welding head 8 up and down to maintain a constant distance. Regardless of the unevenness of the surface of the steel section 11, the plasma arc length can be locked within the optimal process window, greatly improving the internal metallurgical quality and aesthetic appearance of the weld, and avoiding arc breakage or tungsten adhesion shutdown accidents caused by uncontrolled arc length.

[0074] The four sides of the rectangular steel section 11 have rounded corner transition paths at their intersections. A yaw welding head 8 assembly is further superimposed and integrated on the vertical slide plate 91. This yaw welding head 8 assembly includes a rear base 81 rotatably mounted on the vertical slide plate 91. A semi-circular or specific central angle semi-gear ring 811 is provided on the outer surface of the rear base 81. On the opposite fixed surface of the vertical slide plate 91, a yaw motor for outputting deflection torque to the semi-gear ring 811 is firmly installed. The plasma welding head 8 is rigidly mounted on the rear base 81.

[0075] The controller is connected to the active yaw motor 10. During the routine planar straight welding phase, the active yaw motor 10 is in a stationary self-locking state, the rear base 81 remains relatively fixed, and the plasma welding head 8 maintains a stable forward movement perpendicular to the current plane. When the welding head 8 is about to enter the rounded corner transition path on the side of the steel section 11, the controller synchronously sends high-frequency interpolation pulse commands to the lateral feed motor 71, the vertical compensation servo motor 93, and the active yaw motor 10 based on the pre-recorded or real-time scanned mathematical model of the rounded corner radius. In the microseconds of passing through the rounded corner path of the profile, the horizontal slider 62 continues to feed very slowly along the tangent direction. The vertical compensation component drives the vertical slide plate 91 to track the downward curve of the rounded corner profile. The active yaw motor 10 drives the half gear ring 811 to drive the rear base 81 to rotate continuously at small angles according to the derivative of the normal equation of the rounded corner surface. This ensures that the tilt angle of the plasma welding head 8 is dynamically adjusted in real time when it sweeps across the small arc of the rounded corner surface, so that the orientation of the plasma welding gun nozzle is in the same direction as the normal of the rounded corner.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A plasma welding machine for construction engineering, characterized in that, include: frame; Two support units are arranged horizontally at intervals on the frame to support two steel sections to be welded. Clamping and positioning mechanisms are respectively installed on the support unit for clamping and releasing the steel profiles; A rotary welding mechanism, positioned between two support units and fitted over the outside of the butt joint of the two steel sections, includes: The C-shaped frame is rotatably mounted on the machine frame and has circumferential openings for radial insertion and removal of steel profiles; A rotary drive mechanism is arranged between the C-frame and the support unit to drive the C-frame to rotate intermittently at a fixed angle around the circumference; The guide frame is fixed inside the C-frame; The slider and guide slide are mounted on the guide frame; The welding stroke drive mechanism is connected between the guide frame and the slider, driving the slider to reciprocate on the guide frame; The welding head is mounted on the slider, with its end facing the butt joint of the steel section; After the rotary drive mechanism drives the C-frame to rotate intermittently by a set angle so that the sliding direction of the slider is parallel to the butt joint on one side surface of the steel section, the welding stroke drive mechanism drives the welding head to move so that the welding head welds the butt joint on that side.

2. The plasma welding machine for construction engineering according to claim 1, characterized in that, The circumferential extension arc of the C-frame and the guide edge is not less than 270 degrees; The rotary drive mechanism includes an external gear ring fixed to the outer circumferential surface of the C-frame, and a drive gear rotatably mounted on the frame or support unit and meshing with the external gear ring. It also includes a rotary servo motor that drives the C-frame to rotate intermittently in a first direction and continuously in a second direction, wherein the first direction and the second direction are arranged in opposite directions.

3. The plasma welding machine for construction engineering according to claim 2, characterized in that, The cross-section of the steel profile is rectangular. In the first direction, the rotary servo motor drives the C-shaped frame to rotate intermittently along a step of 90°.

4. The plasma welding machine for construction engineering according to claim 2, characterized in that, The outer wall of the C-shaped frame is provided with a guide edge extending in a C-shape, and the support unit is provided with a semi-circular guide groove for sliding engagement of the guide edge.

5. The plasma welding machine for construction engineering according to claim 2, characterized in that, Each support unit includes an outer support seat and an inner support seat arranged at intervals along the extension direction of the steel section. The rotary welding mechanism is located between the two inner support seats, and the C-shaped frame is rotatably assembled on the inner support seat.

6. The plasma welding machine for construction engineering according to claim 1, characterized in that, It also includes a vertical compensation component, which is disposed between the slider and the welding head, and is used to adjust the distance between the welding head and the surface of the steel section in a direction perpendicular to the surface of the steel section.

7. The plasma welding machine for construction engineering according to claim 6, characterized in that, The vertical compensation component includes a vertical slide rail fixed to the slider, a vertical slide plate that slides with the vertical slide rail, and a compensation screw and nut pair and a compensation servo motor for driving the vertical slide plate to rise and fall. The welding head is mounted on the vertical slide plate. The welding machine also includes a controller and a distance sensor arranged on the welding head. The controller is connected to the distance sensor for sampling and to the compensation servo motor for control, so as to adjust the distance between the end of the welding head and the surface of the weld seam in real time after detecting the distance signal of the distance sensor.

8. The plasma welding machine for construction engineering according to claim 7, characterized in that, The welding head includes a rear base rotatably mounted on the vertical slide plate, a semi-gear ring fixed to the outside of the rear base, and an active yaw motor mounted on the vertical slide plate for driving the semi-gear ring to rotate. The welding head is mounted on the rear base, and the controller is connected to the active yaw motor to adjust the orientation of the welding head to be in the same direction as the normal of the rounded corner when passing through the rounded corner path of the profile.

9. The plasma welding machine for construction engineering according to claim 1, characterized in that, The welding stroke drive mechanism includes a transverse lead screw mounted on a guide frame and a feed motor that drives the transverse lead screw to rotate. The slider is threadedly connected to the transverse lead screw.

10. The plasma welding machine for construction engineering according to claim 1, characterized in that, The clamping and positioning mechanism includes two jaws symmetrically arranged perpendicular to the extension direction of the steel profile, and a two-way lead screw or two-way cylinder for driving the two jaws to move towards or away from each other.

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