Ultra-large-cylinder-diameter hydraulic support stand column circular seam deep groove narrow gap welding method

Abstract

The invention discloses a narrow gap welding method for a circular seam deep groove of an ultra-large-cylinder-diameter hydraulic support stand column. The narrow gap welding method comprises the steps of preheating and welding. The rotating motor drives the gear to rotate so that the contact tube rod can rotate, the electric arc at the tip of the welding wire can be driven to swing, and then the side wall fusion depth is increased by setting the parameter relation between the electric arc swing angle and the groove depth. In the welding process, a welding current feedback self-adjusting method is adopted to adjust the dry extension length of a welding wire so as to ensure stable output of welding current, and then the stability of fusion depth is improved; the downward fusion depth and the fusion depth of the side wall can be further improved by adopting a right welding method. The narrow gap welding method has the advantages that compared with a traditional narrow gap welding method, the welding penetration depth and stability can be improved, and the narrow gap welding effect of the circular seam deep groove of the ultra-large-cylinder-diameter hydraulic support stand column is more ideal.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of welding, and particularly relates to a narrow-gap welding method for a ring seam deep groove of an ultra-large cylinder hydraulic support stand column. BACKGROUND

[0002] Coal is the main energy source in China, and hydraulic support is an important supporting equipment for fully mechanized coal mining in coal mines, which mainly provides a safe working space for the coal mining machine and the scraper conveyor. The column in the hydraulic support is a key component that bears a large load, and the column cylinder and the cylinder bottom are connected together by narrow-gap ring seam welding. With the increase of the supporting height of the hydraulic support, the column diameter and the wall thickness gradually increase, and the groove depth of the ring seam welding also increases. The groove depth of the ring seam of the ultra-large cylinder hydraulic support column with an outer cylinder inner hole diameter of greater than or equal to 500 mm and a length of greater than or equal to 2 m can reach 50-100 mm. In order to ensure the bearing capacity of the deep groove column, ER76-G high-strength welding wire is usually used. The traditional narrow-gap welding uses the bending mode of the welding wire to realize the swing of the welding wire, which is particularly prone to produce the side wall unmelted defect, the main reasons are as follows: the strength of the ER76-G welding wire is high, the swing amplitude, swing speed and side wall residence time of the welding wire are not easy to control by using the bending mode of the welding wire, which leads to small side wall penetration and poor stability of the side wall penetration, and even the phenomenon of side wall unmelted occurs; the traditional narrow-gap welding adopts the left welding method, and the downward penetration and the side wall penetration are small; due to the influence of machining precision and clamping precision, the coaxiality of the groove and the welding machine is poor, the dry elongation of the welding wire is easy to change during the welding process, and then the welding arc is unstable, which affects the welding quality.

[0003] In order to improve the quality of the deep groove narrow-gap ring seam welding, the patent for invention with the authorization publication number CN115533259B discloses a coal mine hydraulic support oil cylinder narrow-gap welding seam defect suppression method, which uses heat treatment preheating before welding, optimizes the flame preheating method and the temperature measurement position, optimizes the parameters of the protective gas, optimizes the clamping mode, and adopts the welding method of swing+side wall residence, so that the porosity defect of the oil cylinder ring seam welding is reduced, the residual stress after welding is reduced, and the fusion on both sides of the groove is increased. However, the method still has the problems of poor bending effect of the high-strength welding wire, unstable swing amplitude of the welding arc, slow swing speed, unstable side wall residence time and poor side wall fusion.

[0004] In order to solve the above problems, an ideal technical solution is needed. SUMMARY

[0005] The application is aimed at the above problems, and provides a welding method which can stably control the bending angle of the welding wire, the welding current, the swing angle of the welding arc and the welding penetration.

[0006] In order to achieve the above object, the application discloses a kind of super cylinder hydraulic support column ring seam deep slope narrow gap welding method, the groove size of the ring seam is R4 (delta=1.5~2.5 °), and the groove depth H1=50~100mm;Including the following steps: S1: preheating: preheating temperature 100~250 ℃, preheating range is the both sides of groove;S2: welding: welding process uses right welding method, and is divided into bottom welding, filling welding, cover welding, the welding process uses the way that conductive nozzle reciprocating swing in groove is welded, the axis direction of the conductive nozzle relative to conductive nozzle rod is inclined, and the inclination angle alpha=10~12 °, and conductive nozzle rod rotates and then drives the arc of welding wire tip to swing;The process parameters of the bottom welding are as follows: welding current 220~260 A, welding voltage 24~28 V, welding speed 230~260 mm / min, side wall dwell time 0.2~0.3 s, swing speed 40~50 mm / s, swing angle 11~16 °;The process parameters of the filling welding and cover welding are as follows: welding current 270~310 A, welding voltage 26~31 V, welding speed 260~300 mm / min, side wall dwell time 0.3~0.4 s, swing speed 50~60 mm / s, and the swing angle of filling welding and cover welding is determined by the following relationship parameters: the axis of conductive nozzle rod is midline, the swing angle of arc towards the side wall of groove is beta, the reciprocating swing amplitude of arc is L1, the position depth of arc in groove is H2, and the swing angle beta of filling welding and cover welding is arcsin [(H1-H2-4) x tan delta / 5.35+(1~1.5) / 5.35]; The welding current is adjusted by the following way: real-time acquisition of welding current and comparison with design current, adjusting the length of wire dry extension, and then changing the welding current.

[0007] Further, the preheating range is within 75mm and within the both sides of welding groove.

[0008] The present application sets a specific preheating range, which can achieve the actual preheating effect and avoid energy waste caused by overall preheating.

[0009] Further, the conductive nozzle rod is rotated by the first gear and the second gear driven by the rotary motor.

[0010] The present application uses the combination of rotary motor and gear to drive the rotation of conductive nozzle rod, which has the characteristics of simple structure and practicality.

[0011] Furthermore, the welding current adopts a feedback self-adjustment method: a welding current detector is installed in the welding machine. When the welding current equals the design current, the welding torch height does not need to be adjusted, and the wire extension length remains unchanged. When the welding current exceeds the design current, the welding torch height is increased, the wire extension length is increased, and the welding current is reduced to the set current. When the welding current is less than the design current, the welding torch height is decreased, the wire extension length is reduced, and the welding current is increased to the set current.

[0012] This solution utilizes a welding current feedback self-adjustment method to ensure stable current output during the welding process, thereby improving arc stability and resulting in more stable weld penetration.

[0013] Furthermore, the specific form of the right welding method is as follows: looking from the tail of the cylinder to the cylinder opening, the cylinder rotates counterclockwise, and the direction of cylinder rotation is such that the conductive nozzle rod is located directly above the center line of the bevel and is horizontally offset in the opposite direction of cylinder rotation, with an offset distance L2 = 5~8mm, thereby forming a welding travel angle θ, where θ = 11~15°.

[0014] Compared to traditional narrow-gap welding, this solution can further improve the downward penetration depth and the penetration depth of the bevel sidewall, thereby improving the welding effect of deep bevel narrow-gap welds on the circumferential seam of ultra-large cylinder diameter hydraulic support columns and ensuring the safety of the hydraulic support columns.

[0015] Furthermore, the welding method uses 1.2mm ER76-G welding wire and the shielding gas is 80% argon + 20% carbon dioxide.

[0016] The ER76-G welding wire used in this solution can meet the load-bearing capacity requirements of the hydraulic support column with ultra-large cylinder diameter due to its excellent performance.

[0017] Furthermore, the welding speed for the root pass is equal to the welding current minus 10 ± 10 (mm / min), and the welding speed for the fill pass and cover pass is equal to the welding current ± 10 (mm / min).

[0018] This solution improves the stability of the welding process by setting a relationship between welding speed and welding current.

[0019] Furthermore, by controlling the matching relationship between the welding current and the welding speed, the dwell time and oscillation speed of the arc on the sidewall are determined, ultimately ensuring the weld thickness range of each layer: 4-5 mm for the root pass and 4.5-5.5 mm for the fill pass.

[0020] This method ensures that the weld thickness of each layer remains within a certain range by matching the welding current and welding speed. Welds within this range exhibit relatively good stability in sidewall penetration. Since the arc width is 4-5 mm, if each weld layer is thicker than 5.5 mm, the weld pool becomes too large, preventing the arc from penetrating the entire pool. The furthest point from the arc is the sidewall between layers, where the penetration depth is almost zero, resulting in poor sidewall fusion between layers. Conversely, if each weld layer is less than 4 mm thick, the welding speed becomes too fast. When the welding wire oscillates to one side of the bevel, it needs to travel a long distance to reach the opposite sidewall, making the opposite sidewall prone to incomplete fusion. Furthermore, by controlling the relationship between the welding current and oscillation speed, the arc's dwell time on the sidewall and the oscillation speed can be determined, thereby controlling the arc trajectory. When the welding current is high and the welding speed is fast, a faster oscillation speed is required. This is because at high welding speeds, the welding wire needs to oscillate a longer distance from one bevel sidewall to the other, making it prone to incomplete fusion when it reaches the other sidewall. Increasing the oscillation speed reduces the interval between oscillations, thus improving the fusion of the other sidewall and ensuring the stability of the weld penetration. However, if the oscillation speed is too fast, the arc becomes unstable, the downward weld penetration during oscillation decreases, and arc interruption may even occur. Therefore, the oscillation speed must be adapted to the welding speed and welding current.

[0021] Furthermore, by controlling the swing angle β, the distance between the welding wire tip and the bevel sidewall can be controlled to be within the range of 2.5 to 3 mm.

[0022] This solution can improve the sidewall penetration depth while ensuring that the arc does not deviate towards the sidewall. Because the arc width is 4-5mm, when the distance between the welding wire and the bevel is less than 2.5mm, the arc is closer to the sidewall than to the bottom, causing the arc to drift towards the sidewall and resulting in incomplete fusion at the bottom. When the distance between the welding wire and the bevel is greater than 3mm, the arc is too far from the sidewall, the arc's penetration effect on the sidewall weakens, the sidewall penetration depth will decrease significantly, and incomplete fusion may even occur.

[0023] In summary, the advantages of this invention over the prior art are: 1. By setting the relationship parameters between the oscillation angle and the bevel depth, the matching relationship between welding current, welding speed, sidewall dwell time, and oscillation speed can be improved, and the distance between the arc and the bottom of the bevel and the sidewall of the bevel can be controlled, thereby increasing the sidewall penetration depth.

[0024] 2. By using a welding current feedback self-adjustment method, the height of the welding torch is controlled, thereby controlling the wire extension and welding current, improving arc stability and penetration stability, and mitigating the problem of unstable sidewall penetration caused by the difference in coaxiality between the bevel and the welding machine.

[0025] 3. By optimizing the structure and position of the contact tip and adopting the right-hand welding method, the downward penetration depth and the sidewall penetration depth are further improved, thereby enhancing the welding quality. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the conductive nozzle swinging according to the present invention; Figure 2 This is a schematic diagram of the bevel structure of the present invention; Figure 3 This is a schematic diagram of the conductive nozzle of the present invention driving the electric arc to oscillate inside the bevel; Figure 4 This is a schematic diagram of the right-side welding method used in this invention; Figure 5 This is a schematic diagram of the left welding method using bent welding wire; Figure 6 This is a photograph of a welded joint with a large weld thickness and shallow penetration. Figure 7 A photograph of a welded joint with sidewall incomplete fusion defects; Figure 8 A photograph of a welded joint with deep penetration and no defects; In the diagram: 1. Rotary motor, 2. First gear, 3. Second gear, 4. Conductive nozzle rod, 5. Conductive nozzle, 6. Welding wire tip, 7. Bevel, 8. Bevel sidewall, 9. Bevel bottom, 10. Rotation direction of hydraulic cylinder, 11. Welding travel direction, 12. Weld trajectory, 13. Welding wire bending, 14. Hydraulic cylinder. Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0028] This invention provides a method for welding a deep bevel and narrow gap circumferential joint of a hydraulic support column with an ultra-large cylinder diameter, such as... Figure 2 , Figure 3As shown, the bevel 7 of the circumferential seam has a size of R4×(δ=1.5°~2.5°) and a bevel depth H1=50~100mm; the process includes the following steps: S1: Preheating: the preheating temperature is 100~250℃, and the preheating range is both sides of the bevel 7; S2: Welding: the welding process adopts the right-hand welding method, which is divided into root pass welding, filler weld, and cover weld. The welding process is carried out by the conductive nozzle 5 reciprocating in the bevel 7. The conductive nozzle 5 is tilted relative to the axis of the conductive nozzle rod 4, with an tilt angle α=10~12°. The conductive nozzle rod 4 rotates, thereby causing the arc of the welding wire tip 6 to oscillate; the process parameters for the root pass welding are: welding current 220~260A, welding voltage 24~28V, welding speed 230~260mm / min, sidewall dwell time 0.2~0.3s, oscillation speed 40~50mm / s, and oscillation... The oscillation angle is 11-16°; the process parameters for the filler and capping welds are: welding current 270-310A, welding voltage 26-31V, welding speed 260-300mm / min, sidewall dwell time 0.3-0.4s, and oscillation speed 50-60mm / s. The oscillation angle for the filler and capping welds is determined by the following parameters: with the axis of the conductive nozzle rod 4 as the center line, the oscillation angle of the arc towards the bevel sidewall 8 is β, the arc reciprocating oscillation amplitude is L1, and the arc position depth in the bevel 7 is H2. The oscillation angle β for the filler and capping welds is β=arcsin[(H1-H2-4)×tanδ / 5.35+(1-1.5) / 5.35]; the welding current is adjusted by: real-time acquisition of the welding current and comparison with the design current, adjusting the length of the welding wire extension, and thus changing the welding current.

[0029] Furthermore, the preheating range is 75mm or less on both sides of the welding bevel 7.

[0030] Furthermore, such as Figure 1 As shown, the conductive nozzle rod 4 rotates by driving the first gear 2 and the second gear 3 to rotate via the rotary motor 1.

[0031] Furthermore, the welding current adopts a feedback self-adjustment method: a welding current detector is installed in the welding machine. When the welding current equals the design current, the welding torch height does not need to be adjusted, and the wire extension length remains unchanged. When the welding current exceeds the design current, the welding torch height is increased, the wire extension length is increased, and the welding current is reduced to the set current. When the welding current is less than the design current, the welding torch height is decreased, the wire extension length is reduced, and the welding current is increased to the set current.

[0032] Furthermore, such as Figure 4As shown, the specific form of the right welding method is as follows: looking from the tail of the cylinder 14 towards the cylinder opening, the cylinder 14 rotates counterclockwise, the rotation direction of the cylinder is 10, the conductive nozzle rod 4 is located directly above the center line of the bevel 7 and is horizontally offset in the opposite direction of the cylinder rotation direction 10, the offset distance L2=5~8mm, thereby forming a welding travel angle θ, θ=11~15°, the welding travel direction is 11, and the weld trajectory is 12.

[0033] Furthermore, the welding method uses 1.2mm ER76-G welding wire and the shielding gas is 80% argon + 20% carbon dioxide.

[0034] Furthermore, the welding speed for the root pass is equal to the welding current minus 10 ± 10 (mm / min), and the welding speed for the fill pass and cover pass is equal to the welding current ± 10 (mm / min).

[0035] Furthermore, by controlling the matching relationship between the welding current and the welding speed, the dwell time and oscillation speed of the arc on the sidewall are determined, ultimately ensuring the weld thickness range of each layer: 4-5 mm for the root pass and 4.5-5.5 mm for the fill pass.

[0036] Furthermore, by controlling the swing angle β, the distance between the welding wire tip 6 and the bevel sidewall 8 is controlled to be within the range of 2.5 to 3 mm.

[0037] To make the invention clearer, the welding effect of the invention will be demonstrated below through specific welding implementation schemes.

[0038] Example 1: The cylinder barrel base material is made of 30CrMnSi alloy steel, the cylinder bottom base material is made of 30CrMnSi alloy steel, the cylinder outer diameter is Φ636mm, the wall thickness is 108mm, the bevel depth is H1=100mm, the radius of the bottom of the bevel 9 is R=4mm, and the inclination angle of the bevel sidewall 8 is δ=1.5°.

[0039] Welding using the welding method of this invention, with specific welding process parameters as follows: preheating temperature 200℃, preheating range within 75mm on both sides of the welding groove; narrow gap welding using a conductive nozzle oscillation, shielding gas of 80% argon + 20% carbon dioxide, and welding wire of Φ1.2mm ER76-G high-strength welding wire; a welding current feedback self-adjustment method, with an actual current error of ±3A and an actual voltage error of ±0.2V; conductive nozzle tip tilt angle α = 11°, conductive nozzle offset distance L2 = 8mm, and welding travel angle θ = 11~13°; for the root pass welding, welding current 250A, welding voltage 26V, welding speed 250mm / min, sidewall dwell time 0.2s, oscillation speed 45mm / s, and oscillation angle 14°; for the fill and cover passes welding, welding current 290A, welding voltage 29.5V, welding speed 290mm / min, sidewall dwell time 0.3s, and oscillation speed 55mm / s.

[0040] The filler welding requires a total of 18 layers. The relationship between the distance H2 from the welding wire tip 6 to the bevel surface and the arc oscillation angle β is as follows: For the first layer, H2=90mm, β=15°; for the second layer, H2=85mm, β=16°; for the third layer, H2=80mm, β=17°; for the fourth layer, H2=75mm, β=18.5°; for the fifth layer, H2=70mm, β=20°; for the sixth layer, H2=65mm, β=21.5°; for the seventh layer, H2=60mm, β=23°; for the eighth layer, H2=55mm, β=24.5°; for the ninth layer, H2=50mm, β=26°; for the tenth layer, ... H2=45mm, β=27.5°; when filling the 11th layer, H2=40mm, β=29°; when filling the 12th layer, H2=35mm, β=30.5°; when filling the 13th layer, H2=30mm, β=32°; when filling the 14th layer, H2=25mm, β=33.5°; when filling the 15th layer, H2=20mm, β=35°; when filling the 16th layer, H2=15mm, β=36°; when filling the 17th layer, H2=10mm, β=37°; when filling the 18th layer, H2=5mm, β=38°.

[0041] During the cover welding process, the relationship between the distance H2 from the tip of the welding wire 6 to the bevel surface and the oscillation angle β is: H2=0mm, β=39°.

[0042] Example 2: The cylinder barrel base material is made of S890 steel, the cylinder bottom base material is made of 30CrMnSi alloy steel, the cylinder outer diameter is Φ456mm, the wall thickness is 55mm, the bevel depth is H1=50mm, the radius of the bottom of the bevel 9 is R=4mm, and the inclination angle of the bevel sidewall 8 is δ=2.5°.

[0043] Welding using the welding method of this invention, with specific welding process parameters: preheating temperature 200℃, preheating range within 75mm on both sides of the welding groove; narrow gap welding using a conductive nozzle oscillation, shielding gas of 80% argon + 20% carbon dioxide, welding wire of Φ1.2mm ER76-G high-strength welding wire; a welding current feedback self-adjustment method, with an actual current error of ±2.5A and an actual voltage error of ±0.15V; conductive nozzle tip tilt angle α = 11°, conductive nozzle offset distance L2 = 5mm, welding travel angle θ = 12~14°; for the root pass welding, welding current 255A, welding voltage 26.3V, welding speed 255mm / min, sidewall dwell time 0.3s, oscillation speed 50mm / s, and oscillation angle 12°; for the fill and cover passes welding, welding current 295A, welding voltage 30V, welding speed 295mm / min, sidewall dwell time 0.3s, and oscillation speed 60mm / s.

[0044] The filler welding requires a total of 8 layers. The relationship between the distance H2 from the tip of the welding wire 6 to the bevel surface and the arc oscillation angle β is as follows: When filling the first layer, H2=40mm, β=15°; when filling the second layer, H2=35mm, β=17.5°; when filling the third layer, H2=30mm, β=20°; when filling the fourth layer, H2=25mm, β=23°; when filling the fifth layer, H2=20mm, β=26°; when filling the sixth layer, H2=15mm, β=29°; when filling the seventh layer, H2=10mm, β=32°; when filling the eighth layer, H2=5mm, β=35°.

[0045] During the cover welding process, the relationship between the distance H2 from the tip of the welding wire 6 to the bevel surface and the oscillation angle β is: H2=0mm, β=38°.

[0046] Example 3: The cylinder barrel base material is made of S890 steel, the cylinder bottom base material is made of S890 steel, the cylinder outer diameter is Φ746mm, the wall thickness is 68mm, the bevel depth is H1=65mm, the radius of the bevel bottom 9 is R=4mm, and the inclination angle of the bevel sidewall 8 is δ=2°.

[0047] Welding using the welding method of this invention, with specific welding process parameters as follows: preheating temperature 120℃, preheating range within 70mm on both sides of the welding groove; narrow gap welding using a conductive nozzle oscillation, shielding gas of 80% argon + 20% carbon dioxide, welding wire of Φ1.2mm ER76-G high-strength welding wire; welding current feedback self-adjustment method, with an actual current error of ±3A and an actual voltage error of ±0.2V; conductive nozzle tip tilt angle α = 11°, conductive nozzle offset distance L2 = 5mm, welding travel angle θ = 11~13°; for the root pass welding, welding current 260A, welding voltage 28V, welding speed 260mm / min, sidewall dwell time 0.3s, oscillation speed 50mm / s, and oscillation angle 16°; for the fill and cover passes welding, welding current 310A, welding voltage 31V, welding speed 300mm / min, sidewall dwell time 0.4s, and oscillation speed 60mm / s.

[0048] The filler welding requires a total of 11 layers. The relationship between the distance H2 from the tip of the welding wire 6 to the bevel surface and the arc oscillation angle β is as follows: When filling the first layer, H2=55mm, β=18°; when filling the second layer, H2=50mm, β=20°; when filling the third layer, H2=45mm, β=22°; when filling the fourth layer, H2=40mm, β=24°; when filling the fifth layer, H2=35mm, β=26°; when filling the sixth layer, H2=30mm, β=28°; when filling the seventh layer, H2=25mm, β=30°; when filling the eighth layer, H2=20mm, β=32°; when filling the ninth layer, H2=15mm, β=34°; when filling the tenth layer, H2=10mm, β=36°; when filling the eleventh layer, H2=5mm, β=38°.

[0049] During the cover welding process, the relationship between the distance H2 from the tip of the welding wire 6 to the bevel surface and the oscillation angle β is: H2=0mm, β=40°.

[0050] like Figure 5 As shown, traditional narrow-gap circumferential welding typically employs a left-hand welding method, using a 13-degree bend in the welding wire to achieve the arc oscillation effect. However, in actual use, ER76-G high-strength welding wire is usually selected. Continuing to use the wire bending method makes it difficult to control the oscillation amplitude, oscillation speed, and sidewall dwell time, resulting in shallow sidewall penetration, poor sidewall penetration stability, and even incomplete sidewall fusion.

[0051] The sidewall penetration depth can be measured using metallographic methods, and welding defects can be initially detected using UT flaw detection, with the final defect type determined by metallographic methods. By measuring the sidewall penetration depth values ​​and comparing the welding methods of the present invention with those of traditional welding methods, it is evident that the present invention can significantly improve the sidewall penetration depth and its stability, and reduce sidewall incomplete fusion defects. See Table 1 for a comparison of penetration depth values ​​in specific embodiments.

[0052] Table 1: Comparison of traditional welding methods and the present invention

[0053] like Figure 6 As shown, a mismatch between welding current and welding speed can result in a thicker weld but shallower penetration. Figure 7 As shown, a mismatch between welding current and welding speed can lead to defects such as incomplete fusion of the sidewalls. Figure 8 As shown, the welding method of the present invention can produce welds with large penetration depth and no defects.

[0054] In summary, this invention, by setting the relationship parameters between the distance H2 from the welding wire tip 6 to the bevel surface and the arc oscillation angle β, and simultaneously controlling the matching relationship between welding current and welding speed, ultimately ensures that the weld thickness of each layer is within the range of 4-5 mm for the root pass and 4.5-5.5 mm for the fill pass, with good stability of the sidewall penetration depth. By employing a welding current feedback self-adjustment method to control the welding torch height, and thus the length of the welding wire extension, the welding current is stabilized within the design current range, ultimately ensuring arc stability and solving the problem of unstable sidewall penetration depth caused by poor coaxiality between the bevel and the welding machine. By improving the traditional narrow-gap welding method and adopting a right-hand welding method with a welding travel angle θ of 11-15°, the downward penetration depth and sidewall penetration depth are further improved.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for welding a deep bevel and narrow gap circumferential joint of a hydraulic support column with an ultra-large cylinder diameter, wherein the bevel (7) of the circumferential joint has a size of R4×(δ=1.5°~2.5°) and a bevel depth H1=50~100mm; characterized in that: Includes the following steps: S1: Preheating: Preheating temperature 100~250℃, preheating range is both sides of the bevel (7); S2: Welding: The welding process adopts the right welding method, which is divided into root welding, fill welding and cover welding. The welding process is carried out by the conductive nozzle (5) reciprocating in the groove (7). The conductive nozzle (5) is tilted relative to the axis of the conductive nozzle rod (4) with an inclination angle α = 10~12°. The conductive nozzle rod (4) rotates, which in turn drives the arc of the welding wire tip (6) to oscillate. The process parameters for the root pass welding are: welding current 220-260A, welding voltage 24-28V, welding speed 230-260mm / min, sidewall dwell time 0.2-0.3s, oscillation speed 40-50mm / s, and oscillation angle 11-16°. The process parameters for the filler weld and cover weld are: welding current 270-310A, welding voltage 26-31V, welding speed 260-300mm / min, side wall dwell time 0.3-0.4s, and oscillation speed 50-60mm / s. The oscillation angle of the filler weld and cover weld is determined by the following parameters: with the axis of the conductive nozzle rod (4) as the center line, the oscillation angle of the arc toward the bevel side wall (8) is β, the arc reciprocating oscillation amplitude is L1, and the arc position depth in the bevel (7) is H2. The oscillation angle β of the filler weld and cover weld is arcsin[(H1-H2-4)×tanδ / 5.35+(1-1.5) / 5.35]; The welding current is adjusted by: collecting the welding current in real time and comparing it with the design current, adjusting the length of the welding wire extension, and thus changing the welding current.

2. The method for welding a deep bevel and narrow gap circumferential seam of an ultra-large cylinder diameter hydraulic support column according to claim 1, characterized in that: The preheating range is 75mm or less on both sides of the welding bevel (7).

3. The method for welding a deep bevel and narrow gap circumferential seam of an ultra-large cylinder diameter hydraulic support column according to claim 1, characterized in that: The conductive nozzle rod (4) rotates by driving the first gear (2) and the second gear (3) to rotate via the rotary motor (1).

4. The method for welding a deep bevel and narrow gap circumferential seam of an ultra-large cylinder diameter hydraulic support column according to claim 1, characterized in that: The welding current adopts a feedback self-adjustment method: a welding current detector is installed in the welding machine. When the welding current equals the design current, the welding torch height does not need to be adjusted, and the wire extension length remains unchanged. When the welding current exceeds the design current, the welding torch height is increased, the wire extension length is increased, and the welding current is reduced to the set current. When the welding current is less than the design current, the welding torch height is decreased, the wire extension length is reduced, and the welding current is increased to the set current.

5. The method for welding a deep bevel and narrow gap circumferential seam of an ultra-large cylinder diameter hydraulic support column according to claim 1, characterized in that: The specific form of the right welding method is as follows: looking from the tail of the cylinder (14) towards the cylinder opening, the cylinder (14) rotates counterclockwise, the rotation direction of the cylinder is (10), the conductive nozzle rod (4) is located directly above the center line of the bevel (7) and is horizontally offset in the opposite direction of the rotation direction of the cylinder (10), the offset distance L2=5~8mm, thereby forming a welding travel angle θ, θ=11~15°, the welding travel direction is (11), and the weld trajectory is (12).

6. The method for welding a deep bevel and narrow gap circumferential seam of an ultra-large cylinder diameter hydraulic support column according to claim 1, characterized in that: The welding method uses 1.2mm ER76-G welding wire and a shielding gas of 80% argon + 20% carbon dioxide.

7. The method for welding a deep bevel and narrow gap circumferential seam of an ultra-large cylinder diameter hydraulic support column according to claim 1, characterized in that: The welding speed for the root pass is equal to the welding current minus 10 ± 10 (mm / min), and the welding speed for the fill pass and cover pass is equal to the welding current minus 10 (mm / min).

8. The method for welding a deep bevel and narrow gap circumferential joint of an ultra-large cylinder diameter hydraulic support column according to claim 7, characterized in that: By controlling the matching relationship between the welding current and the welding speed, the dwell time and oscillation speed of the arc on the sidewall are determined, ultimately ensuring the weld thickness range of each layer: 4-5 mm for the root pass and 4.5-5.5 mm for the fill pass.

9. The method for welding a deep bevel and narrow gap circumferential seam of an ultra-large cylinder diameter hydraulic support column according to claim 1, characterized in that: By controlling the swing angle β, the distance between the welding wire tip (6) and the bevel sidewall (8) is controlled to be within the range of 2.5 to 3 mm.

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