A flame heating method for welding thick plate drum welds

Abstract

The present invention relates to a flame heating method for the weld of a thick plate drum in the field of crane manufacturing technology, which includes the following steps: Step 1: Place the drum on the workbench of the welding equipment and adjust the position of the drum so that the weld is directly above; Step 2: According to the length of the drum, arrange multiple flame guns on the top frame of the flame heating equipment, and then place the flame heating equipment horizontally and centrally in the inner cavity of the drum; Step 3: Adjust the height of the top frame through the adjusting device of the flame heating equipment so that the distance between the inner top wall of the drum and the flame gun is a specific height; The present invention arranges multiple flame guns at specific horizontal and vertical intervals, and makes the top frame move longitudinally back and forth in the drum to form a heat diffusion area, ensuring a more uniform temperature distribution during the preheating and post-heat treatment processes of the drum weld area, and helping to reduce welding quality problems caused by local overheating or insufficient heating.

Description

Technical Field

[0001] The present invention relates to the technical field of crane manufacturing, and in particular to a flame heating method for welding thick plate drum welds. Background Technique

[0002] The drum is a key stressed component in hoisting and transporting machinery. The welded drum has the advantages of light self-weight and strong bearing capacity, so most of the drums of current large-scale hoisting and transporting equipment adopt welded drums.

[0003] Welding quality has a crucial impact on the safety performance of hoisting machinery and the service life of equipment. For welding thick plate drums in a low-temperature environment, preheating is required during the welding process to ensure welding quality.

[0004] At present, the commonly used heating methods during the welding process of large welded drums are divided into flame heating and far-infrared heating. The existing flame heating method is as follows: a fixed frame is used to clamp the torch, the heating points are fixed, and the temperature of the heating area is uneven.

[0005] Therefore, we have designed a flame heating method for welding thick plate drum welds. Summary of the Invention

[0006] In order to overcome the deficiencies in the background technique, the present invention discloses a flame heating method for welding thick plate drum welds.

[0007] To achieve the above-mentioned invention purpose, the present invention adopts the following technical solutions:

[0008] A flame heating method for welding thick plate drum welds includes the following steps:

[0009] Step 1: Place the drum on the welding equipment workbench and adjust the position of the drum so that the weld is directly above.

[0010] Step 2: According to the length of the drum, arrange multiple flame guns on the top frame of the flame heating equipment with a horizontal spacing W of 160 - 180 mm and a vertical spacing L of 450 - 500 mm, and then place the flame heating equipment horizontally and centered in the drum cavity.

[0011] Step 3: Adjust the height of the top frame through the adjusting device of the flame heating equipment so that the distance H from the inner top wall of the drum to the flame gun is 145 - 155 mm.

[0012] Step 4: Ignite the flame gun and start the driving device of the flame heating equipment. The driving device drives the top frame to reciprocate longitudinally within a moving stroke S, where S = L - L / 10 mm.

[0013] Step 5: When the temperature of the workpiece welding area reaches the specified preheating temperature T_1, start the welding operation until completion, where during the welding process, the temperature of the workpiece welding area is between the specified preheating temperature T_1 and the interpass temperature T_2;

[0014] Step 6: Adjust the gas flow rate of the flame gun so that the temperature of the workpiece welding area quickly rises to the established post-weld hydrogen removal heat treatment temperature T_3 and maintain for the established time t;

[0015] Step 7: Turn off the flame gun and the flame heating equipment, cover the weld area with asbestos cloth for heat preservation and slow cooling until room temperature.

[0016] Preferably, the specified preheating temperature T_1 is 80 - 120 °C.

[0017] Preferably, the established post-weld hydrogen removal heat treatment temperature T_3 is 250 - 300 °C.

[0018] Preferably, the established time t = 30 + k(D - 20) min, where k is a constant between 1.8 and 2.2, and D is the wall thickness of the drum.

[0019] Preferably, the temperature of the workpiece welding area in Step 5 and Step 6 is monitored in real time by an infrared thermometer installed on the top frame.

[0020] Preferably, the flame heating equipment includes:

[0021] A bottom frame for horizontally placing inside the drum to be welded;

[0022] An intermediate frame longitudinally movably arranged on the top of the bottom frame;

[0023] A driving device arranged on the bottom frame for driving the intermediate frame to reciprocate;

[0024] A sliding fit structure arranged between the bottom frame and the intermediate frame for ensuring the stability and sliding performance of the intermediate frame;

[0025] A top frame located above the intermediate frame and whose height can be adjusted by an adjusting device;

[0026] Multiple flame guns equally spaced on both sides of the top frame for flame heating of the drum;

[0027] An infrared thermometer installed on the top frame for monitoring the temperature.

[0028] Preferably, support crossbars are provided at positions near both ends of the bottom surface of the bottom frame to adapt to the welding operations of drums with different diameters;

[0029] The supporting cross bar includes a fixed sleeve and a movable insertion rod. The movable insertion rod is axially and movably inserted into the fixed sleeve and its position is locked by a locking bolt.

[0030] Preferably, the driving device includes a reduction motor installed on the bottom frame, a radial rotating rod arranged on the output shaft of the reduction motor, a rotating shaft and a strip-shaped frame arranged at the end of the radial rotating rod. The strip-shaped frame is correspondingly connected to the intermediate frame, and its inner cavity is movably matched with the shaft body of the rotating shaft, so that the reduction motor drives the radial rotating rod to rotate, and then drives the rotating shaft to move in a circular motion, causing the strip-shaped frame to reciprocate or swing, realizing the reciprocating movement of the intermediate frame;

[0031] Wherein, the strip-shaped frame is vertically arranged and is fixedly connected to the intermediate frame correspondingly.

[0032] Or one end of the strip-shaped frame is correspondingly hinged to the bottom frame and is movably connected to the intermediate frame through a movable shaft penetrating its inner cavity.

[0033] Preferably, the adjusting device includes a screw rod and a pressing nut. The lower end of the screw rod is fixedly connected to the intermediate frame, and the upper end penetrates the top frame. The pressing nut is located below the top frame and is in threaded cooperation with the screw rod.

[0034] Preferably, the infrared thermometer is located at the middle position between two adjacent flame guns in the longitudinal direction.

[0035] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects:

[0036] 1. By arranging multiple flame guns at specific horizontal and vertical intervals, and enabling the top frame to perform longitudinal reciprocating movement in the drum, a heat diffusion area is formed, ensuring more uniform temperature distribution during the preheating and post-heat treatment processes of the drum weld area, and helping to reduce welding quality problems caused by local overheating or insufficient heating;

[0037] 2. Using the infrared thermometer to monitor the temperature of the workpiece welding area in real time, the gas flow rate of the flame gun can be adjusted according to the actual situation, thereby realizing precise control of the temperature of the workpiece welding area, ensuring that the temperature conditions during the welding process meet the requirements, and improving the welding quality;

[0038] 3. The setting of the supporting cross bar enables this flame heating device to be applicable to drum welding operations with different diameters and sizes, not only increasing the application range of the device, but also improving the flexibility and convenience of operation.

[0039] 4. The design of the sliding fit structure ensures the stability of the intermediate frame during the movement process. At the same time, the height of the top frame can be precisely adjusted through the adjusting device to meet the requirements of different welding positions. These characteristics work together to ensure the stable and reliable operation of this flame heating device during the entire heating process. Brief Description of the Drawings

[0040] Figure 1 This is a schematic structural diagram of the flame heating device in the present invention;

[0041] Figure 2 This is the front view of the flame heating device in use in the present invention;

[0042] Figure 3 This is a partial assembly schematic diagram of the bottom frame, middle frame and driving device in the present invention;

[0043] Figure 4 is Figure 3 right view of;

[0044] Figure 5 This is a partial assembly schematic diagram of another structure of the bottom frame, middle frame and driving device in the present invention.

[0045] In the figure: 1, bottom frame; 2, support cross bar; 21, fixed sleeve; 22, movable insertion rod; 23, locking bolt; 3, middle frame; 4, driving device; 41, reduction motor; 42, radial rotating rod; 43, rotating shaft; 44, strip-shaped frame; 45, movable shaft; 5, sliding fit structure; 51, linear chute; 52, roller; 6, top frame; 7, adjusting device; 71, screw rod; 72, top pressure nut; 8, flame gun; 9, infrared thermometer. Detailed Description of the Invention

[0046] The present invention can be explained in detail through the following embodiments. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "front", "rear", "left", "right", etc. indicating the orientation or position relationship, it is only corresponding to the drawings of the present application for the convenience of describing the present invention; it should be understood that if there are terms such as "end", "side", "end part", "side part", "transverse", "longitudinal", etc. indicating the orientation or position relationship, it is only corresponding to the length and width of the corresponding component, that is, the "end part" indicates the head and tail regions in the length direction of the corresponding component, and the "side part" indicates the head and tail regions in the width direction of the corresponding component; it is for the convenience of describing the present invention rather than indicating or implying that the device or element referred to must have a specific orientation.

[0047] Embodiment 1, in combination with the attached Figures 1-5 , a flame heating method for welding the weld of a thick plate drum includes the following steps:

[0048] Step 1: Place the drum on the workbench of the welding equipment and adjust the position of the drum so that the weld is directly above.

[0049] Step 2: According to the length of the reel, a plurality of flame guns 8 are arranged on the top frame 6 of the flame heating device with a horizontal spacing W of 160 - 180 mm and a vertical spacing L of 450 - 500 mm, and then the flame heating device is horizontally centered and placed in the inner cavity of the reel.

[0050] That is to say: The flame guns 8 have two rows and multiple columns. The distance between the flame guns 8 in two rows is 160 - 180 mm, and the distance between two adjacent columns of flame guns 8 in the same row is 450 - 500 mm; specifically, the number of flame guns 8 in each row is related to the length of the reel, so the number of flame guns 8 in each row is not specifically limited.

[0051] It should be noted that: The flame heating device is horizontally centered and placed in the inner cavity of the reel can be understood as: The center of the flame heating device and the center of the reel are on the same vertical line. At this time, the horizontal distance between the flame gun 8 and the weld is 80 - 90 mm.

[0052] To reduce the height of the flame heating device, or in other words, to better adapt to reels of different diameters, a support crossbar 2 that can axially expand and contract is horizontally spanned at the bottom of the flame heating device; by adjusting the expansion and contraction of the support crossbar 2 to use reels of different diameters, the bottom of the flame heating device is made to be as close as possible to the horizontal diameter position of the reel; that is to say, the height of the flame heating device located in the inner cavity of the reel can be increased as much as possible.

[0053] Furthermore, the support crossbar 2 includes a fixed sleeve 21 installed on the bottom surface of the bottom frame 1, and movable insertion rods 22 are axially and movably inserted at both ends of the fixed sleeve 21; among them, a locking bolt 23 is screwed at the end of the fixed sleeve 21, and the movable insertion rod 22 is locked by squeezing the movable insertion rod 22 with the locking bolt 23.

[0054] Step 3: Adjust the height of the top frame 6 through the adjusting device 7 of the flame heating device so that the height H between the inner top wall of the reel and the flame gun 8 is 145 - 155 mm.

[0055] Furthermore, since the top frame 6 needs to move longitudinally back and forth, an intermediate frame 3 that is vertically movably matched with the top frame 6 is also provided on the flame heating device, and the height of the top frame 6 is adjusted through the intermediate frame 3.

[0056] Specifically, the intermediate frame 3 has an adjusting device 7 for adjusting the height of the top frame 6.

[0057] In a possible implementation manner, the adjusting device 7 can be a jack.

[0058] In a possible implementation manner, the adjusting device 7 can be a screw rod 71 whose lower end is rotatably connected to the intermediate frame 3. The rod body of the screw rod 71 penetrates through the top frame 6 and is threadedly engaged with the top frame 6.

[0059] In a possible implementation, in combination with the attached Figure 2 , the adjusting device 7 can be a screw rod 71 fixedly connected to the lower end of the middle frame 3. The rod body of the screw rod 71 passes through the top frame 6, and a pressing nut 72 is provided at a position of the rod body of the screw rod 71 below the top frame 6.

[0060] As required, at least three adjusting devices 7 are provided. When there are three adjusting devices 7, they are distributed in a triangular shape to ensure the stability of the top frame 6. When there are four adjusting devices 7, they are four distributed in a rectangular shape.

[0061] Step Four: Light the flame gun 8 and start the driving device 4 of the flame heating device. The driving device 4 drives the top frame 6 to reciprocate longitudinally within the moving stroke S, where S = L - L / 10 mm; with this setting, longitudinally, the area between the two flame guns 8 with a length of L / 10 mm is the area not directly heated by the flame guns 8, that is, the heat diffusion area; since after the flame gun 8 moves to the extreme position, due to the need to change the moving direction, the drum at this position is heated for a longer time than other positions, which easily causes the temperature to be higher than the welding interlayer temperature T_2. The existence of the heat diffusion area can absorb the heat at this position, thereby ensuring the temperature balance of the workpiece welding area and preventing the temperature at this position from being higher than the welding interlayer temperature T_2 and affecting the welding quality.

[0062] Further, the driving device 4 drives the middle frame 3 to reciprocate longitudinally, driving the top frame 6 to reciprocate longitudinally.

[0063] Even further, in combination with the attached Figures 3-5 , the driving device 4 includes a reduction motor 41. A radial rotating rod 42 is installed on the output shaft of the reduction motor 41. One end of the radial rotating rod 42 is provided with a rotating shaft 43. The rotating shaft 43 is engaged with a strip-shaped frame 44, and the strip-shaped frame 44 is correspondingly connected to the middle frame 3. Specifically, the rotating shaft 43 is engaged with the inner cavity of the strip-shaped frame 44. More specifically, the rotating shaft 43 can move along the length direction of the strip-shaped frame 44. Specifically, the central axis direction of the output shaft of the reduction motor 41 is perpendicular to the moving direction of the middle frame 3. Preferably, the central axis direction of the output shaft of the reduction motor 41 is the horizontal direction.

[0064] In a possible implementation, in combination with the attached Figure 5 , the strip-shaped frame 44 is fixedly connected to the middle frame 3; that is, the operation of the reduction motor 41 can drive the radial rotating rod 42 to rotate, and then drive the rotating shaft 43 to move in a circular motion along the circumference of the output shaft of the reduction motor 41. Then, the rotating shaft 43 drives the strip-shaped frame 44 to reciprocate, realizing the function of driving the middle frame 3 to reciprocate.

[0065] In another possible implementation, in combination with the attached Figures 3-4, one end of the strip-shaped frame 44 is correspondingly connected and hinged to the bottom frame 1, and the intermediate frame 3 is provided with a movable shaft 45 inserted into the inner cavity of the strip-shaped frame 44. That is, the operation of the reduction motor 41 can drive the radial rotating rod 42 to rotate, and then drive the rotating shaft 43 to move in a circular motion along the output shaft of the reduction motor 41. Then, the rotation drives the strip-shaped frame 44 to swing reciprocally, and then drives the movable shaft 45 to move reciprocally, realizing the function of driving the intermediate frame 3 to move reciprocally. In this embodiment, the rotation center of the strip-shaped frame 44 and the output shaft of the reduction motor 41 are in the same vertical plane.

[0066] To reduce the length of the radial rotating rod 42, the rotation center of the strip-shaped frame 44 and the movable shaft 45 are respectively located on both sides of the rotating shaft 43.

[0067] As required, a sliding fit structure 5 is provided between the bottom of the intermediate frame 3 and the top of the bottom frame 1; further, the sliding fit structure 5 can be a slide rail pair in the prior art, or a linear chute 51 provided on the top surface of the bottom frame 1 and a roller 52 provided on the bottom surface of the intermediate frame 3, where the roller 52 rolls in the cavity of the linear chute 51; among them, at least two rollers 52 are provided along the longitudinal direction of the bottom surface of the sliding fit structure 5.

[0068] Furthermore, to ensure the stability of the intermediate frame 3, a sliding fit structure 5 is provided on each side of the bottom frame 1 and the intermediate frame 3.

[0069] Step Five: When the temperature of the workpiece welding area reaches the specified preheating temperature T_1, start the welding operation until completion, where during the welding process, the temperature of the workpiece welding area is between the specified preheating temperature T_1 and the interlayer welding temperature T_2;

[0070] To better control the temperature of the workpiece welding area, the temperature of the workpiece welding area can be monitored in real time by an infrared thermometer 9 provided on the top frame 6, and the purpose of controlling the temperature of the workpiece welding area can be achieved by adjusting the gas flow rate of the flame gun 8.

[0071] As required, the infrared thermometer 9 is located at the middle position between two adjacent flame guns 8 in the longitudinal direction.

[0072] Further, the specified preheating temperature T_1 is 80~120°C; specifically, the specified preheating temperature T_1 is related to the ambient temperature, the thickness of the thick plate, and the material of the thick plate, and no specific limitation is made here.

[0073] In the example, when the ambient temperature is -5°C, the material of the thick plate is Q355C, and the thickness of the thick plate is 25mm, the specified preheating temperature is 80°C; when the ambient temperature is 10°C, the material of the thick plate is 35# steel, and the thickness of the thick plate is 42mm, the specified preheating temperature is 100°C; when the ambient temperature is 20°C, the material of the thick plate is Q690B, and the thickness of the thick plate is 60mm, the specified preheating temperature is 120°C.

[0074] It should be noted that the interpass temperature T_2 of welding is 230 °C.

[0075] In this step, to prevent the temperature of the welding area of the workpiece from being lower than the specified preheating temperature T_1 or higher than the interpass temperature T_2 of welding, it is necessary to adjust the gas flow rate of the flame gun 8. The specific adjustment method is as follows: when the temperature of the welding area of the workpiece is rising and the temperature of the welding area of the workpiece is higher than T_2 - (T_2 - T_1) / 5 °C, the gas flow rate of the flame gun 8 is reduced to lower the temperature of the welding area of the workpiece; when the temperature of the welding area of the workpiece is falling and the temperature of the welding area of the workpiece is lower than T_1 + (T_2 - T_1) / 5 °C, the gas flow rate of the flame gun 8 is increased to raise the temperature of the welding area of the workpiece.

[0076] For easy understanding, taking the ambient temperature of -5 °C, the thick plate material of Q355C, and the thick plate thickness of 25 mm as an example, when the temperature of the welding area of the workpiece is rising and the temperature of the welding area of the workpiece is higher than 200 °C, the gas flow rate of the flame gun 8 is reduced; when the temperature of the welding area of the workpiece is falling and the temperature of the welding area of the workpiece is lower than 110 °C, the gas flow rate of the flame gun 8 is increased.

[0077] Step Six: Adjust the gas flow rate of the flame gun 8 to quickly raise the temperature of the welding area of the workpiece to the established post-weld hydrogen removal heat treatment temperature T_3 and maintain it for the established time t; as required, the established post-weld hydrogen removal heat treatment temperature T_3 is 250 - 300 °C.

[0078] Furthermore, the established time t = 30 + k(D - 20) min, where k is a constant of 1.8 - 2.2 and D is the wall thickness of the drum.

[0079] To better control the temperature of the welding area of the workpiece, the temperature of the welding area of the workpiece can be monitored in real time by the infrared thermometer 9 installed on the top frame 6, and the temperature of the welding area of the workpiece can be controlled by adjusting the gas flow rate of the flame gun 8.

[0080] The specific method of adjusting the gas flow rate of the flame gun 8 is as follows: when the temperature of the welding area of the workpiece is rising and the temperature of the welding area of the workpiece is higher than the upper limit of T_3 - (the upper limit of T_3 - the lower limit of T_3) / 5 °C, that is, when the temperature of the welding area of the workpiece is higher than 290 °C, the gas flow rate of the flame gun 8 is reduced to lower the temperature of the welding area of the workpiece; when the temperature of the welding area of the workpiece is falling and the temperature of the welding area of the workpiece is lower than the lower limit of T_3 + (the upper limit of T_3 - the lower limit of T_3) / 5 °C, that is, when the temperature of the welding area of the workpiece is lower than 260 °C, the gas flow rate of the flame gun 8 is increased to raise the temperature of the welding area of the workpiece.

[0081] Step Seven: Turn off the flame gun 8 and the flame heating device, cover the weld area with asbestos cloth for heat preservation and slow cooling until room temperature;

[0082] Among them, the flame heating device also has a bottom frame 1, and two support cross bars 2 are arranged at both ends of the bottom of the bottom frame 1.

[0083] The parts not detailed in the present invention are the prior art. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and are intended to include all changes falling within the meaning and scope of the equivalent elements within the present invention.

Claims

1. A flame heating method for welding thick plate coil welds, characterized in that: The following steps are involved: Step 1: Place the reel on the welding equipment workbench and adjust the reel position so that the weld is directly above; Step 2: according to the length of the roll, a plurality of flame guns (8) are arranged on the top frame (6) of the flame heating device in a manner such that the horizontal spacing W is 160-180 mm and the vertical spacing L is 450-500 mm, and then the flame heating device is horizontally and centrally placed in the inner cavity of the roll; Step 3: adjusting the height of the top frame (6) by means of the adjusting device (7) of the flame heating device so that the height H between the top wall of the roll and the flame gun (8) is 145-155 mm; Step 4: Ignite the flame gun (8) and start the driving device (4) of the flame heating device, the driving device (4) drives the top frame (6) to move back and forth longitudinally within a moving stroke S, where S=LL / 10mm; Step 5: When the temperature of the welding area of ​​the workpiece reaches the specified preheating temperature T_1, the welding operation is started until it is completed, wherein during the welding process, the temperature of the welding area of ​​the workpiece is between the specified preheating temperature T_1 and the welding interlayer temperature T_2; Step 6: Adjust the gas flow rate of the flame gun (8) so that the temperature of the welding area of ​​the workpiece rises rapidly to a predetermined post-weld dehydrogenation heat treatment temperature T_3 and is maintained for a predetermined time t; Step 7: Turn off the flame gun (8) and the flame heating device, cover the weld area with asbestos cloth to keep it warm and slowly cool it down to room temperature; Wherein, the flame heating equipment comprises: A bottom frame (1) is used to be placed horizontally in the inner cavity of the reel to be welded; An intermediate frame (3) is disposed on the top of the bottom frame (1) in a longitudinally movable manner; A driving device (4) is provided on the bottom frame (1) and is used to drive the middle frame (3) to move back and forth; A sliding matching structure (5) is provided between the bottom frame (1) and the middle frame (3) and is used to ensure the stability and sliding performance of the middle frame (3); A top frame (6) located above the middle frame (3) and having a height adjustable by an adjustment device (7); A plurality of flame guns (8) are arranged at equal intervals on both sides of the top frame (6) for performing flame heating on the roll; An infrared thermometer (9) is mounted on the top frame (6) to monitor the temperature.

2. The flame heating method for welding thick plate drum weld according to claim 1 is characterized in that: The prescribed preheating temperature T_1 is 80~120°C.

3. The flame heating method for welding thick plate drum weld according to claim 1 is characterized in that: The predetermined post-weld dehydrogenation heat treatment temperature T_3 is 250~300°C.

4. The flame heating method for welding thick plate drum weld according to claim 1 is characterized in that: The predetermined time t=30+k(D-20)min, wherein k is a constant of 1.8-2.2, and D is the wall thickness of the roll.

5. The flame heating method for welding thick plate drum weld according to claim 1, characterized in that: The temperature of the welding area of ​​the workpiece in step five and step six is ​​monitored in real time by an infrared thermometer (9) arranged on the top frame (6).

6. The flame heating method for welding thick plate drum weld according to claim 1, characterized in that: The bottom surface of the bottom frame (1) is provided with supporting cross bars (2) near both ends to accommodate welding operations of coils with different diameters; The supporting crossbar (2) comprises a fixed sleeve (21) and a movable insertion rod (22); the movable insertion rod (22) is axially movably inserted into the fixed sleeve (21) and is locked in position by a locking bolt (23).

7. The flame heating method for welding thick plate drum weld according to claim 1, characterized in that: The driving device (4) comprises a reduction motor (41) mounted on the bottom frame (1), a radial rotating rod (42) arranged on the output shaft of the reduction motor (41), a rotating shaft (43) arranged at the end of the radial rotating rod (42), and a strip frame (44); the strip frame (44) is correspondingly connected to the middle frame (3), and the inner cavity and the shaft body of the rotating shaft (43) are movably matched, so that the reduction motor (41) drives the radial rotating rod (42) to rotate, thereby driving the rotating shaft (43) to move in a circle, so that the strip frame (44) reciprocates or swings, thereby realizing the reciprocating movement of the middle frame (3); The strip frame (44) is arranged vertically and fixedly connected to the middle frame (3). Alternatively, one end of the strip frame (44) is hinged to the bottom frame (1) and is movably connected to the middle frame (3) via a movable shaft (45) that passes through its inner cavity.

8. The flame heating method for welding thick plate drum weld according to claim 1, characterized in that: The adjusting device (7) comprises a screw rod (71) and a pressing nut (72); the lower end of the screw rod (71) is fixedly connected to the middle frame (3) and the upper end passes through the top frame (6); the pressing nut (72) is located below the top frame (6) and is threadably matched with the screw rod (71).

9. The flame heating method for welding thick plate drum weld according to claim 1, characterized in that: The infrared thermometer (9) is located in the middle of two flame guns (8) adjacent to each other in the longitudinal direction.

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