Nickel-based alloy pipeline and welding method thereof

Abstract

The invention discloses a nickel-based alloy pipeline and a welding method thereof. According to the welding method of the nickel-based alloy pipeline, a 5G all-position laser welding method is adopted for welding a to-be-welded pipeline; wherein the to-be-welded pipeline comprises a first nickel-based alloy pipeline and a second nickel-based alloy pipeline which are in butt joint, and the butt joint position of the first nickel-based alloy pipeline and the second nickel-based alloy pipeline is a to-be-welded surface; the face to be welded sequentially comprises a flat welding area, a downward vertical welding area, an overhead welding area and an upward vertical welding area in the welding direction. And the laser power corresponding to the downward vertical position welding area, the overhead position welding area and the upward vertical position welding area is sequentially increased. According to the welding method, one-side welding and one-time forming can be achieved, the forming quality is excellent, and the welding production efficiency is greatly improved; and the problem of serious welding seam oxidation caused by the high-power welding process can be effectively controlled, and the mechanical property and the corrosion resistance of the nickel-based alloy pipeline joint are improved.

Description

Technical Field

[0001] The present invention relates to a nickel-based alloy pipeline and a welding method thereof. Background Art

[0002] Nickel-based alloys, especially GH3535 alloy, have excellent high-temperature performance and good corrosion resistance, and are a popular solution for the molten salt transportation pipeline materials in the fourth-generation thorium-based nuclear reactor. The all-position butt welding of medium-caliber pipelines is a common application scenario for pressure pipeline welding in the nuclear power industry. Currently, for this welding requirement, the existing technology that can achieve single-sided welding with double-sided forming of GH3535 alloy butt pipelines with an outer diameter φ of 141.3 mm and a wall thickness of 9.53 mm is as follows: adopting the arc filler wire welding method, opening a V-shaped groove, fixing the axis direction of the pipeline parallel to the ground, starting the arc from the 6 o'clock position of the pipeline butt joint, and welding from the front of the V-shaped groove to the 12 o'clock position in two half circles along the clockwise and counterclockwise directions respectively, and multi-layer and multi-pass welding is required for the left and right weld beads.

[0003] In the implementation of the existing welding technology, due to the relatively thick wall thickness of the nickel-based alloy pipeline, not less than 8 mm, the arc filler wire welding technology needs to open a groove in advance, with two welding directions, using single-sided welding and multi-layer and multi-pass welding. The welding process is complex, the operation difficulty is large, the production efficiency is low, welding defects such as excessive height and hump are likely to appear on the front of the weld, and forming defects such as collapse and weld tumor are likely to appear on the back of the weld. Summary of the Invention

[0004] Aiming at the problems such as forming defects existing in the single-sided welding of nickel-based alloy pipelines in the prior art, the present invention provides a nickel-based alloy pipeline and a welding method thereof. The welding method of the nickel-based alloy pipeline can be welded into shape at one time. No welding defects such as excessive height and hump will appear on the front of the obtained weld, and the forming quality of the back of the weld is good, without forming defects such as collapse and weld tumor; this welding method is simple and has high production efficiency.

[0005] The present invention adopts the following technical solutions to solve the above technical problems.

[0006] The present invention provides a welding method for a nickel-based alloy pipeline, which uses a 5G all-position laser welding method to weld the pipeline to be welded;

[0007] Wherein, the pipeline to be welded includes a first nickel-based alloy pipeline and a second nickel-based alloy pipeline in butt joint, and the butt joint of the first nickel-based alloy pipeline and the second nickel-based alloy pipeline is the surface to be welded; the surface to be welded is in a protective gas atmosphere, and the protective gas includes a front protective gas, a side protective gas and a back protective gas;

[0008] The surface to be welded sequentially includes a flat welding area, a downward vertical welding area, an overhead welding area and an upward vertical welding area in the welding direction;

[0009] Among them, the laser power corresponding to the downward vertical welding area, the overhead welding area, and the upward vertical welding area increases in sequence.

[0010] In the present invention, the 5G all-position laser welding method is a laser welding method for pipelines. During the welding process, the pipeline to be welded is placed horizontally and fixed (±15°), and it does not rotate during welding. Multiple welding methods such as flat welding, downward vertical welding, upward vertical welding, and overhead welding can be achieved on the surface to be welded.

[0011] In the present invention, the flat welding area refers to the area on the surface to be welded that is far from the plane where the pipeline to be welded is placed and the connection line of the two endpoints is parallel to the plane where the pipeline to be welded is placed; the overhead welding area refers to the area on the surface to be welded that is close to the plane where the pipeline to be welded is placed and the connection line of the two endpoints is parallel to the plane where the pipeline to be welded is placed; the downward vertical welding area refers to the area on the surface to be welded where the connection line of the two endpoints is perpendicular to the plane where the pipeline to be welded is placed and the welding direction is close to the plane where the pipeline to be welded is placed; the upward vertical welding area refers to the area on the surface to be welded where the connection line of the two endpoints is perpendicular to the plane where the pipeline to be welded is placed and the welding direction is away from the plane where the pipeline to be welded is placed.

[0012] In the present invention, the welding direction can be clockwise or counterclockwise.

[0013] In the present invention, the total increase value of the laser power is preferably 0.3 - 1 kW, more preferably 0.5 - 1 kW, for example, 0.75 kW or 0.8 kW.

[0014] In the present invention, preferably, the angles between the downward vertical welding area, the overhead welding area, and the upward vertical welding area and the geometric center of the surface to be welded are equal. The angle refers to the angle formed by the connection lines of the starting position and the ending position of each area and the geometric center of the surface to be welded.

[0015] In the present invention, preferably, the angle between the flat welding area and the geometric center of the surface to be welded is 20° - 100°, for example, 90°.

[0016] In the present invention, preferably, the angle between the downward vertical welding area and the geometric center of the surface to be welded is 20° - 100°, for example, 90°.

[0017] In the present invention, preferably, the angle between the overhead welding area and the geometric center of the surface to be welded is 20° - 100°, for example, 90°.

[0018] In the present invention, preferably, the angle between the upward vertical welding area and the geometric center of the surface to be welded is 20° - 100°, for example, 90°.

[0019] In the present invention, the welding may sequentially include an arc starting stage, a welding stage, and an arc ending stage according to the welding direction; the arc starting area corresponding to the arc starting stage and the arc ending area corresponding to the arc ending stage fall within the flat welding area, and the arc ending area covers the arc starting area; the welding area corresponding to the welding stage includes the area other than the arc ending area in the flat welding area, the downward vertical welding area, the overhead welding area, and the upward vertical welding area.

[0020] In some embodiments, the angle between the arc starting area and the geometric center of the surface to be welded may be 5° - 10°, preferably 8°. The angle refers to the angle formed by the connecting lines between the starting position and the ending position of the arc starting area and the geometric center of the surface to be welded respectively.

[0021] In some embodiments, the angle between the arc ending area and the geometric center of the surface to be welded may be 10° - 20°, preferably 16°. The angle refers to the angle formed by the connecting lines between the starting position and the ending position of the arc ending area and the geometric center of the surface to be welded respectively.

[0022] In some embodiments, the welding area includes a first flat welding area, a first downward vertical welding area, a second downward vertical welding area, a first overhead welding area, a second overhead welding area, a first upward vertical welding area, a second upward vertical welding area, and a second flat welding area;

[0023] The laser power corresponding to the first flat welding area, the first downward vertical welding area, the second downward vertical welding area, the first overhead welding area, the second overhead welding area, the first upward vertical welding area, the second upward vertical welding area, and the second flat welding area increases in a gradient manner.

[0024] Among them, preferably, the angle between the first flat welding area and the geometric center of the surface to be welded is 35° - 40°, such as 37°.

[0025] Among them, preferably, the angles between the first downward vertical welding area, the second downward vertical welding area, the first overhead welding area, the second overhead welding area, the first upward vertical welding area, and the second upward vertical welding area and the geometric center of the surface to be welded are equal.

[0026] Among them, preferably, the angle between the second flat welding area and the geometric center of the surface to be welded is 25° - 30°, such as 29°.

[0027] Among them, preferably, the gradient is an equal gradient.

[0028] Among them, the step size of the gradient is preferably 20 - 300W, more preferably 20 - 150W, such as 62.5W, 75W, 100W, 125W, 200W, or 250W.

[0029] Preferably, the step size of each gradient is 125 W, and the total increase value of the laser power is 1 kW.

[0030] Preferably, the step size of each gradient is 62.5 W, and the total increase value of the laser power is 500 W.

[0031] In some specific embodiments, the welding area includes a first flat welding area, a first downward vertical welding area, a second downward vertical welding area, a first overhead welding area, a second overhead welding area, a first upward vertical welding area, a second upward vertical welding area, and a second flat welding area; the laser power corresponding to the first flat welding area, the first downward vertical welding area, the second downward vertical welding area, the first overhead welding area, the second overhead welding area, the first upward vertical welding area, the second upward vertical welding area, and the second flat welding area is increased in gradients, the step size of each gradient is 125 W, and the total increase value of the laser power is 1 kW; the angles between the first downward vertical welding area, the second downward vertical welding area, the first overhead welding area, the second overhead welding area, the first upward vertical welding area, and the second upward vertical welding area and the geometric center of the surface to be welded are all 45°, the angle between the first flat welding area and the geometric center of the surface to be welded is 37°, and the angle between the second flat welding area and the geometric center of the surface to be welded is 29°.

[0032] In some specific embodiments, the welding area includes a first flat welding area, a first downward vertical welding area, a second downward vertical welding area, a first overhead welding area, a second overhead welding area, a first upward vertical welding area, a second upward vertical welding area, and a second flat welding area; the laser power corresponding to the first flat welding area, the first downward vertical welding area, the second downward vertical welding area, the first overhead welding area, the second overhead welding area, the first upward vertical welding area, the second upward vertical welding area, and the second flat welding area is increased in gradients, the step size of each gradient is 62.5 W, and the total increase value of the laser power is 500 W; the angles between the first downward vertical welding area, the second downward vertical welding area, the first overhead welding area, the second overhead welding area, the first upward vertical welding area, and the second upward vertical welding area and the geometric center of the surface to be welded are all 45°, the angle between the first flat welding area and the geometric center of the surface to be welded is 37°, and the angle between the second flat welding area and the geometric center of the surface to be welded is 29°.

[0033] In some embodiments, the welding area includes a first flat welding area, a downward vertical welding area, an overhead welding area, an upward vertical welding area, and a second flat welding area; the laser powers at the end positions of the first flat welding area, the downward vertical welding area, the overhead welding area, the upward vertical welding area, and the second flat welding area are a1, b, c, d, and a2 respectively, which satisfy: a1 < b < c ≤ d ≤ a2.

[0034] Wherein, the first flat welding area refers to the area in the surface to be welded that is far from the plane where the pipe to be welded is placed and close to the downward vertical welding area in the area where the line connecting the two endpoints is parallel to the plane where the pipe to be welded is placed; the second flat welding area refers to the area in the surface to be welded that is far from the plane where the pipe to be welded is placed and close to the upward vertical welding area in the area where the line connecting the two endpoints is parallel to the plane where the pipe to be welded is placed.

[0035] Wherein, preferably, a2 - a1 is 0.3 - 1 kW, more preferably 0.5 - 1 kW, for example 0.75 kW or 0.8 kW.

[0036] Wherein, preferably, b - a1 is 0.1 - 0.3 kW, more preferably 0.1 - 0.2 kW.

[0037] Wherein, preferably, c - b is 0.1 - 0.3 kW, more preferably 0.1 - 0.2 kW.

[0038] Wherein, preferably, b - a1 = c - b.

[0039] Wherein, preferably, c - a1 is 0.2 - 0.7 kW, for example 0.4 kW, 0.5 kW or 0.6 kW.

[0040] Wherein, preferably, a2 - c is 0 - 0.1 kW, for example 0.05 kW.

[0041] Wherein, preferably, a1 is 9 - 12 kW, for example 9.5 kW.

[0042] Wherein, preferably, a2 is 9.3 - 13 kW, for example 10 kW or 9.75 kW.

[0043] Wherein, preferably, the included angle between the first flat welding area and the geometric center of the surface to be welded is 35° - 40°, for example 37°.

[0044] Wherein, preferably, the included angles between the downward vertical welding area, the overhead welding area and the upward vertical welding area and the geometric center of the surface to be welded are equal.

[0045] Wherein, preferably, the included angle between the second flat welding area and the geometric center of the surface to be welded is 25° - 30°, for example 29°.

[0046] In some embodiments, by adjusting the power according to the welding position, the laser power is increased in the downward vertical welding area, further increased in the overhead welding area, further increased in the upward vertical welding area or the laser power at the overhead welding position is maintained, and further increased in the second flat welding area or the laser power at the upward vertical welding area is maintained, so as to obtain excellent surface forming quality. This is because in the second flat welding area, the gravity is consistent with the laser penetration direction, and the weld is prone to collapse; in the downward vertical welding area, the gravity is perpendicular to the laser penetration direction, which is likely to cause the molten metal of the weld to flow downward, resulting in the lack of the required weld reinforcement height of the formed weld; in the overhead welding area, the gravity is opposite to the laser penetration direction. In order to ensure full penetration of the weld, the power needs to be further increased on the basis of the downward vertical welding area; in the upward vertical welding area, the gravity is perpendicular to the laser penetration direction, which is likely to cause the molten metal of the weld to flow downward, resulting in too high weld reinforcement height of the formed weld.

[0047] In some specific embodiments, the welding area includes a first flat welding area, a downward vertical welding area, an overhead welding area, an upward vertical welding area and a second flat welding area; the laser power at the end position of the first flat welding area is 9.1 kW, the laser power at the end position of the downward vertical welding area is 9.4 kW, the laser power at the end position of the overhead welding area is 9.7 W, the laser power at the end position of the upward vertical welding area is 9.75 kW, and the laser power at the end position of the second flat welding area is 9.75 kW; the included angles of the downward vertical welding area, the overhead welding area and the upward vertical welding area with the geometric center of the surface to be welded are all 90°, the included angle of the first flat welding area with the geometric center of the surface to be welded is 37°, and the included angle of the second flat welding area with the geometric center of the surface to be welded is 29°.

[0048] In some specific embodiments, the welding area includes a first flat welding area, a downward vertical welding area, an overhead welding area, an upward vertical welding area and a second flat welding area; the laser power at the end position of the first flat welding area is 9.6 kW, the laser power at the end position of the downward vertical welding area is 9.8 kW, the laser power at the end position of the overhead welding area is 10 W, the laser power at the end position of the upward vertical welding area is 10 kW, and the laser power at the end position of the second flat welding area is 10 kW; the included angles of the downward vertical welding area, the overhead welding area and the upward vertical welding area with the geometric center of the surface to be welded are all 90°, the included angle of the first flat welding area with the geometric center of the surface to be welded is 37°, and the included angle of the second flat welding area with the geometric center of the surface to be welded is 29°.

[0049] In the present invention, those skilled in the art understand that the welding surfaces of the first nickel-based alloy pipe and the second nickel-based alloy pipe completely coincide, and their shapes and dimensions are identical.

[0050] In the present invention, the material of the first nickel-based alloy pipe is preferably nickel-chromium alloy, nickel-chromium-molybdenum alloy, nickel-chromium-iron alloy or nickel-chromium-molybdenum-iron alloy. The nickel-chromium-molybdenum-iron alloy is preferably Ni-16Mo-7Cr-4Fe, such as GH3535 alloy.

[0051] In the present invention, the material of the second nickel-based alloy pipe is preferably nickel-chromium alloy, nickel-chromium-molybdenum alloy, nickel-chromium-iron alloy or nickel-chromium-molybdenum-iron alloy. The nickel-chromium-molybdenum-iron alloy is preferably Ni-16Mo-7Cr-4Fe, such as GH3535 alloy.

[0052] In the present invention, the length of the first nickel-based alloy pipe can be 70 - 150 mm, for example, 90 mm.

[0053] In the present invention, the length of the second nickel-based alloy pipe can be 70 - 150 mm, for example, 90 mm.

[0054] In the present invention, preferably, the outer diameter of the pipe to be welded is 130 mm - 200 mm, more preferably 130 - 180 mm, for example, 141.3 mm.

[0055] In the present invention, preferably, the wall thickness of the pipe to be welded is 8 - 12 mm, for example, 9.53 mm or 9.1 mm. The wall thickness of the pipe to be welded refers to half of the difference between the outer diameter and the inner diameter of the pipe at the welding surface of the pipe to be welded.

[0056] In the present invention, preferably, the diameter of the laser spot for welding is 0.1 - 0.4 mm, for example, 0.4 mm.

[0057] In the present invention, the defocus amount for welding is preferably -1 to -10 mm, for example, -5 mm. Generally, the defocus amount is divided into positive defocus amount and negative defocus amount. "+" represents positive defocus amount, and "-" represents negative defocus amount.

[0058] In the present invention, the welding speed is preferably 1.8 - 3 m / min, for example, 2.4 m / min.

[0059] In the present invention, the laser beam for welding preferably adopts a perpendicular incidence method. Herein, "perpendicular incidence" means that the laser beam is incident along a direction perpendicular to the surface of the pipe to be welded.

[0060] In the present invention, the welding preferably uses a single-sided laser.

[0061] In the present invention, the laser used for welding may be an adjustable laser conventionally used in the art, preferably a fiber laser, a CO2 laser or a semiconductor laser.

[0062] In the present invention, preferably, the arcing time in the arcing stage is 0 - 1000 ms, for example, 800 ms. During the arcing time, the laser power is linearly increased from 0 kW to the laser power at the starting position of the welding stage in the arcing stage.

[0063] In the present invention, preferably, the arc extinguishing time in the arc extinguishing stage is 800 - 1500 ms, for example, 1000 ms. During the arc extinguishing time, the laser power is linearly decreased from the laser power at the end position of the welding stage to 0 kW in the arc extinguishing stage.

[0064] In the present invention, the method for preparing the pipeline to be welded preferably includes the following steps: butt - jointing and fixing the welding surfaces of the first nickel - based alloy pipeline and the second nickel - based alloy pipeline to obtain the pipeline to be welded.

[0065] In some preferred embodiments, after the butt - jointing, the gap between the welding surfaces of the first nickel - based alloy pipeline and the second nickel - based alloy pipeline is preferably 0 - 0.1 mm, more preferably 0 - 0.05 mm. The gap refers to the difference in the length direction of the welding surfaces of the first nickel - based alloy pipeline and the second nickel - based alloy pipeline.

[0066] In some preferred embodiments, after the butt - jointing, the misalignment amount between the first nickel - based alloy pipeline and the second nickel - based alloy pipeline is preferably 0 - 1 mm. The misalignment amount refers to the difference in the thickness direction of the welding surfaces of the first nickel - based alloy pipeline and the second nickel - based alloy pipeline.

[0067] In some preferred embodiments, a pretreatment step is further included before the butt - jointing. The pretreatment step is conventional in the art and generally includes the machining of the pipeline to be welded and the cleaning of the pipeline to be welded.

[0068] Among them, the purpose of the machining of the pipeline to be welded is to make the pipeline to be welded flat, so that the gap and misalignment amount between the welding surfaces of the first nickel - based alloy pipeline and the second nickel - based alloy pipeline are controlled within a certain range.

[0069] Among them, the cleaning preferably uses ethanol to wipe the welding surfaces of the first nickel - based alloy pipeline and the second nickel - based alloy pipeline. Specifically, use a non - woven fabric sprayed with ethanol to wipe the inner and outer surfaces of the pipeline within 30 mm from the butt - joint surface in one direction, and wipe the welding surface in one direction.

[0070] In some preferred embodiments, the fixing method is spot welding. Among them, the laser power for the spot welding is preferably 3 - 5 kW, such as 3.5 kW; the light output time for the spot welding is preferably 400 - 800 ms, such as 600 ms; preferably, 4 - 6 fixing points are provided for the spot welding.

[0071] In some preferred embodiments, the outer diameter of the pipe to be welded is less than 150 mm, 4 fixing points are provided for the spot welding, and the 4 fixing points equally divide the surface to be welded into four parts.

[0072] In some preferred embodiments, the outer diameter of the pipe to be welded is more than 150 mm, 6 fixing points are provided for the spot welding, and the 6 fixing points equally divide the surface to be welded into six parts.

[0073] In the present invention, along the gas outlet direction of the side protective gas, the horizontal distance between the outlet of the side protective gas and the laser beam is preferably 2 - 5 mm, more preferably 2 - 3 mm, such as 2 mm.

[0074] In the present invention, along the gas outlet direction of the front protective gas, the vertical distance between the outlet of the front protective gas and the surface of the pipe to be welded is preferably 3 - 7 mm, more preferably 3 - 5 mm, such as 3 mm.

[0075] In the present invention, the side protective gas can be provided by a side blowing protection device, and the gas outlet direction of the side blowing protection device is perpendicular to the laser beam direction; the horizontal distance between the gas outlet direction of the side blowing protection device and the welding laser beam is preferably 2 - 5 mm, such as 2 mm.

[0076] In the present invention, the front protective gas can be provided by a drag shield protection device, and the gas outlet direction of the drag shield protection device is parallel to the pipe radial direction; the vertical distance between the drag shield protection device and the surface of the pipe to be welded is preferably 3 - 7 mm, such as 3 mm. The radian at the bottom of the drag shield protection device is consistent with the radian of the pipe to be welded, ensuring to create a uniform protective gas atmosphere above the surface to be welded of the pipe to be welded.

[0077] In the present invention, the back shielding gas is provided by a back shielding device. The back shielding device is arranged by using a high-temperature resistant material to block both ends of the pipeline to be welded, and shielding gas hoses are respectively arranged at the upper and lower ends of the high-temperature resistant materials blocked on both sides. The flow of the back shielding gas can be realized by inputting and discharging the shielding gas through the hoses. In the device of the back shielding gas, the air inlet and outlet of the shielding gas hoses at the upper and lower ends of the high-temperature resistant materials blocked on both sides of the connecting pipeline should be considered according to the type of shielding gas passed. When the density of the shielding gas ≥ the density of air, the air inlet end is the lower shielding gas hose, and the air outlet end is the upper shielding gas hose. When the density of the shielding gas is less than the density of air, the air inlet end is the upper shielding gas hose, and the air outlet end is the lower shielding gas hose. Among them, the high-temperature resistant material is, for example, a high-temperature silicone foam board.

[0078] In the present invention, the types of the front shielding gas, the side shielding gas and the back shielding gas are inert shielding gases for conventional welding, preferably including one or more of nitrogen, argon and helium.

[0079] In the present invention, the shielding gas can be introduced by introducing the shielding gas into the shielding gas hoses connected to each shielding device.

[0080] In the present invention, the gas flow rate of the side shielding gas is preferably 3 - 15 L / min, for example, 10 L / min.

[0081] In the present invention, the gas flow rate of the front shielding gas is preferably 30 - 45 L / min, for example, 35 L / min.

[0082] In the present invention, before the welding, the gas flow rate of the back shielding gas is 20 - 45 L / min, for example, 40 L / min.

[0083] In the present invention, preferably, after the inside of the pipeline to be welded is filled with the shielding gas, the welding is carried out.

[0084] In the present invention, preferably, during the welding, the gas flow rate of the back shielding gas is 3 - 5 L / min, for example, 5 L / min.

[0085] In the present invention, preferably, a welding robot is used for 5G all-position laser welding.

[0086] The present invention also provides a nickel-based alloy pipeline obtained by the welding method of the nickel-based alloy pipeline as described above.

[0087] On the basis of conforming to the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0088] The reagents and raw materials used in the present invention are all commercially available.

[0089] The positive and progressive effects of the present invention are as follows:

[0090] In the present invention, by regulating the laser power of welding to sequentially experience maintaining the initial laser power unchanged, increasing, increasing, and decreasing from the starting position to the ending position, it is possible to achieve one-time forming of the 5G all-position single-sided welding of the surface to be welded of a nickel-based alloy pipe without beveling, and the forming quality is excellent. There will be no welding defects such as excessive height and humps on the front of the obtained circumferential weld, and the forming quality of the back of the circumferential weld is good, without forming defects such as collapse and weld bead; this welding method is simple and has high production efficiency; moreover, it can effectively control the serious oxidation problem of the weld caused by the high-power welding process, and improve the mechanical and corrosion resistance properties of the nickel-based alloy pipe joint. Description of the Drawings

[0091] Figure 1 It is a schematic structural diagram of the front protection device in Example 1. Reference numerals: 1 is the shielding gas hose, 2 is the side-blowing protection device, 3 is the drag shield protection device, 4 is the outlet direction of the side shielding gas, 5 is the laser beam, 6 is the horizontal distance between the side-blowing protection device and the laser beam, 7 is the vertical distance between the drag shield protection device and the surface of the pipe to be welded, and 8 is the pipe to be welded.

[0092] Figure 2 It is a schematic structural diagram of the back protection device in Example 1. Reference numerals: 9 is the high-temperature silica gel foam board, and 10 is the surface to be welded.

[0093] Figure 3 It is a schematic diagram of the positions of the starting arc area, welding area, and ending arc area of the surface to be welded in Example 3, where (A4), (A3), (A2), (A1), (A8), (A7), (A6), and (A5) are the schematic diagrams of the area positions of 0° - 45°, 45° - 90°, 90° - 135°, 135° - 180°, 180° - 225°, 225° - 270°, 270° - 315°, and 315° - 360° respectively. Reference numerals: starting arc area 101; first flat welding area 11; downward vertical welding area 12; overhead welding area 13; upward vertical welding area 14; second flat welding area 15; ending arc area 102.

[0094] Figure 4 It is an X-ray diagram of the circumferential weld of the nickel-based alloy pipe obtained by the welding method in Example 1. (4), (3), (2), (1), (8), (7), (6), and (5) are the X-ray diagrams of the circumferential weld corresponding to the areas of 0° - 45°, 45° - 90°, 90° - 135°, 135° - 180°, 180° - 225°, 225° - 270°, 270° - 315°, and 315° - 360° respectively.

[0095] Figure 5Surface forming pictures of the circumferential welds of nickel-based alloy pipes obtained by the welding method in Example 1. (A4), (A3), (A2), (A1), (A8), (A7), (A6), and (A5) are the front forming pictures of the circumferential welds corresponding to the 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° regions respectively. (a4), (a3), (a2), (a1), (a8), (a7), (a6), and (a5) are the back forming pictures of the circumferential welds corresponding to the 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° regions respectively.

[0096] Figure 6 Surface forming pictures of the circumferential welds of nickel-based alloy pipes obtained by the welding method in Example 2. (A4), (A3), (A2), (A1), (A8), (A7), (A6), and (A5) are the front forming pictures of the circumferential welds corresponding to the 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° regions respectively. (a4), (a3), (a2), (a1), (a8), (a7), (a6), and (a5) are the back forming pictures of the circumferential welds corresponding to the 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° regions respectively.

[0097] Figure 7 Surface forming pictures of the circumferential welds of nickel-based alloy pipes obtained by the welding method in Example 3. (A4), (A3), (A2), (A1), (A8), (A7), (A6), and (A5) are the front forming pictures of the circumferential welds corresponding to the 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° regions respectively. (a4), (a3), (a2), (a1), (a8), (a7), (a6), and (a5) are the back forming pictures of the circumferential welds corresponding to the 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° regions respectively.

[0098] Figure 8X-ray diagram of the circumferential weld of the nickel-based alloy pipe obtained by the welding method in Example 3. (4), (3), (2), (1), (8), (7), (6), and (5) are the X-ray diagrams of the circumferential weld corresponding to the regions of 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° respectively.

[0099] Figure 9 Surface forming pictures of the circumferential weld of the nickel-based alloy pipe obtained by the welding method in Example 4. (A4), (A3), (A2), (A1), (A8), (A7), (A6), and (A5) are the front forming pictures of the circumferential weld corresponding to the regions of 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° respectively. (a4), (a3), (a2), (a1), (a8), (a7), (a6), and (a5) are the back forming pictures of the circumferential weld corresponding to the regions of 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° respectively.

[0100] Figure 10 Surface forming pictures of the circumferential weld of the nickel-based alloy pipe obtained by the welding method in Comparative Example 1. (A4), (A3), (A2), (A1), (A8), (A7), (A6), and (A5) are the front forming pictures of the circumferential weld corresponding to the regions of 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° respectively. (a4), (a3), (a2), (a1), (a8), (a7), (a6), and (a5) are the back forming pictures of the circumferential weld corresponding to the regions of 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° respectively.

[0101] Figure 11It is a surface forming picture of the circumferential weld of a nickel-based alloy pipe obtained by the welding method in Comparative Example 2. (A4), (A3), (A2), (A1), (A8), (A7), (A6), and (A5) are the front forming pictures of the circumferential weld corresponding to the 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° regions respectively. (a4), (a3), (a2), (a1), (a8), (a7), (a6), and (a5) are the back forming pictures of the circumferential weld corresponding to the 0°-45°, 45°-90°, 90°-135°, 135°-180°, 180°-225°, 225°-270°, 270°-315°, and 315°-360° regions respectively. Detailed implementation mode

[0102] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. For the experimental methods without specific conditions in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0103] In the following examples and comparative examples, the material of the nickel-based alloy pipe used is nickel-chromium-molybdenum-iron alloy (Ni-16Mo-7Cr-4Fe), specifically GH3535 alloy.

[0104] Example 1

[0105] In this example, the test material is a GH3535 alloy pipe with an outer diameter of 141.3 mm and a wall thickness of 9.53 mm.

[0106] The welding method includes the following steps:

[0107] (1) Preparation of the pipe to be welded:

[0108] Step 1: Take two GH3535 alloy pipe segments with a length of 90 mm, an outer diameter of 141.3 mm, and a wall thickness of 9.53 mm. The butt surfaces of the two alloy pipe segments are processed flat by wire cutting and then surface milling. The inner and outer surfaces of the pipe within 30 mm from the butt surface are wiped in one direction with a non-woven fabric sprayed with alcohol reagent, and the surface to be welded 10 is wiped in one direction and dried;

[0109] Step 2: Butt-joint the cleaned and dried GH3535 alloy pipes in Step 1 (the butt-joint is the welding surface 10 to be welded) to obtain the pipes 8 to be welded. Fix the pipes 8 to be welded with a C-type clamp to ensure zero gap between the GH3535 welded pipe segments and a misalignment of 0 mm. Spot-weld and fix the pipes 8 to be welded, set 4 fixing points, divide the welding surface to be welded into four equal parts, which are the 0°, 90°, 180°, and 270° positions of the pipe-to-pipe butt-weld seam (taking the starting position of welding as 0°). The laser power for spot-welding and fixing is 3.5 kW, and the light-emitting time is 600 ms; Assemble the pipes 8 to be welded with a three-jaw chuck and fix the axis direction of the pipes horizontally with the ground. Obtain the pipes 8 to be welded.

[0110] (2) Weld using the 5G all-position laser welding method:

[0111] Step 3: Install the front protection device (side-blowing protection device and drag shield protection device) around the GH3535 alloy pipes 8 to be welded fixed in Step 2 (as Figure 1 shown). The outlet direction 4 of the side protection gas provided by the side-blowing protection device 2 is perpendicular to the direction of the laser beam 5, and the horizontal distance 6 between the side-blowing protection device and the laser beam is 2 mm; The arc of the drag shield protection device 3 should be consistent with the arc of the pipes 8 to be welded. The outlet direction of the front protection gas provided by the drag shield protection device 3 is parallel to the radial direction of the pipes 8 to be welded, and the vertical distance 7 between the drag shield protection device and the surface of the pipes 8 to be welded is 3 mm. Seal both ends of the pipes 8 to be welded with a high-temperature silicone foam board 9, and set protection gas hoses 1 at the upper and lower ends of the foam boards on both sides respectively (as Figure 2 shown). Pass nitrogen protection gas through the protection gas hoses connected to each protection device. Among them, the gas flow rate in the protection gas hose connected to the side-blowing protection device is controlled at 10 L / min, the gas flow rate in the protection gas hose 1 connected to the drag shield protection device is controlled at 35 L / min, and the gas flow rate in the protection gas hoses 1 connected to the high-temperature silicone foam boards blocking both sides of the pipes is controlled at 40 L / min before welding. Inflate for 10 min. After the pipes are filled with nitrogen protection gas, turn the protection gas flow rate to 5 L / min and then carry out welding; The inlet end of the foam boards blocking both sides of the pipes is the upper protection gas hose, and the outlet end is the lower protection gas hose.

[0112] Step 4: Select a fiber laser and use single-sided laser (the laser beam is vertically incident). The laser welding energy parameters are set as follows: the spot diameter is 0.4 mm, and the laser power is 9.5 kW; The laser welding motion parameters are set as follows: the defocus amount is -5 mm, and the welding speed is 2.4 m / min.

[0113] Step 5: Weld according to the preset laser welding parameters. The welding direction is clockwise. This welding sequentially includes the arc-starting stage, the welding stage, and the arc-ending stage according to the welding direction;

[0114] Among them, taking the starting position of welding as 0°, the laser power in the range of 8° - 344° is controlled to increase linearly from 9.5 kW to 10.5 kW. The welding areas corresponding to the welding stage successively include the first flat welding area of 8° - 45°, the first downward vertical welding area of 45° - 90°, the second downward vertical welding area of 90° - 135°, the first overhead welding area of 135° - 180°, the second overhead welding area of 180° - 225°, the first upward vertical welding area of 225° - 270°, the second upward vertical welding area of 270° - 315°, and the second flat welding area of 315° - 344°. Accordingly, the laser power is divided into 8 gradients in sequence, and the step size of each gradient is 125 W;

[0115] Among them, the starting arc area corresponding to the starting arc stage is 0° - 8°. During the starting arc stage, the starting arc program is executed until the end position of the starting arc area (denoted as 8°). The starting arc time is 800 ms. During the starting arc stage, the laser power is linearly increased from 0 kW to the welding power of 9.5 kW; When welding reaches the starting position of the finishing arc area (denoted as 344°), it enters the finishing arc stage. The finishing arc program is executed until the starting arc area corresponding to the starting arc stage is covered to complete welding (the end position can be denoted as 368°), which can achieve smooth lap joint between the finishing arc area and the starting arc area of the weld seam. The finishing arc time is 1000 ms. During the finishing arc stage, the laser power is linearly decreased from 10.5 kW to 0 kW; The entire butt joint welding of the pipeline is completed in one welding process.

[0116] After welding is completed, a nickel-based alloy pipeline is obtained.

[0117] Example 2

[0118] In this example, the test material is a GH3535 alloy pipeline with an outer diameter of 141.3 mm and a wall thickness of 9.1 mm.

[0119] There are differences between Steps 4 and 5 in the welding method and those in Example 1, and the remaining conditions are the same as those in Example 1. Specifically, Steps 4 and 5 are as follows:

[0120] Step 4: Select to use a fiber laser, adopt single-sided laser (the laser beam is vertically incident), and the laser welding energy parameters are set as: the spot diameter is 0.4 mm, and the laser power is 9.5 kW; The laser welding motion parameters are set as: the defocus amount is -5 mm, and the welding speed is 1.8 m / min.

[0121] Step 5: Weld according to the preset laser welding parameters. The welding direction is clockwise. This welding successively includes the starting arc stage, the welding stage, and the finishing arc stage in the welding direction;

[0122] Among them, taking the starting position of welding as 0°, the laser power in the range of 8° - 344° is controlled to increase linearly from 9.5 kW to 10 kW. The welding areas corresponding to the welding stage successively include a first flat welding area of 8° - 45°, a first downward vertical welding area of 45° - 90°, a second downward vertical welding area of 90° - 135°, a first overhead welding area of 135° - 180°, a second overhead welding area of 180° - 225°, a first upward vertical welding area of 225° - 270°, a second upward vertical welding area of 270° - 315°, and a second flat welding area of 315° - 344°. Accordingly, the laser power is divided into 8 gradients in sequence, and the step size of each gradient is 62.5 W;

[0123] Among them, the starting arc area corresponding to the starting arc stage is 0° - 8°. During the starting arc stage, the starting arc program is executed until the end position of the starting arc area (denoted as 8°). The starting arc time is 800 ms. During the starting arc stage, the laser power is controlled to linearly increase slowly from 0 kW to the welding power of 9.5 kW. When welding reaches the starting position of the arc extinguishing area (denoted as 344°), it enters the arc extinguishing stage. The arc extinguishing program is executed until the starting arc area corresponding to the starting arc stage is covered to complete the welding (the end position can be denoted as 368°). The smooth lap of the arc extinguishing area and the starting arc area of the weld seam can be realized. The arc extinguishing time is 1000 ms. During the arc extinguishing stage, the laser power is controlled to linearly decrease slowly from 10 kW to 0 kW; the welding of the entire pipeline butt joint is completed in one welding process.

[0124] Example 3

[0125] In this example, the test material is a GH3535 alloy pipeline with an outer diameter of 141.3 mm and a wall thickness of 9.53 mm.

[0126] There are differences between steps 4 and 5 in the welding method and those in Example 2, and the remaining conditions are the same as those in Example 2. Specifically, steps 4 and 5 are as follows:

[0127] Step 4: Select to use a fiber laser, adopt unilateral laser (the laser beam is vertically incident), and the laser welding energy parameters are set as follows: the spot diameter is 0.4 mm, and the laser power is 9 kW; the laser welding motion parameters are set as follows: the defocus amount is -5 mm, and the welding speed is 2.4 m / min.

[0128] Step 5: Weld according to the preset laser welding parameters. The welding direction is clockwise. This welding successively includes a starting arc stage, a welding stage, and an arc extinguishing stage in the welding direction;

[0129] Among them, taking the starting position of welding as 0°, the laser power in the range of 8° - 344° is controlled to increase from 9 kW to 9.75 kW. The welding areas corresponding to the welding stage successively include the first flat welding area 11 (8° - 45°), the downward vertical welding area 12 (45° - 135°), the overhead welding area 13 (135° - 225°), the upward vertical welding area 14 (225° - 315°), and the second flat welding area 15 (315° - 344°); the laser power in the first flat welding area 11 gradually rises from 9 kW to 9.1 kW, the laser power in the downward vertical welding area 12 gradually rises from 9.1 kW to 9.4 kW, the laser power in the overhead welding area 13 gradually rises from 9.4 kW to 9.7 kW, and the laser power in the upward vertical welding area 14 gradually rises from 9.7 kW to 9.75 kW; the laser power in the second flat welding area 15 remains unchanged at 9.75 kW;

[0130] Among them, the starting arc area 101 corresponding to the starting arc stage is 0° - 8°. During the starting arc stage, the starting arc program is executed until the end position of the starting arc area 101 (recorded as 8°), the starting arc time is 800 ms, and the laser power is controlled to linearly rise from 0 kW to the welding power of 9 kW during the starting arc stage; when welding reaches the starting position of the finishing arc area 102 (recorded as 344°), it enters the finishing arc stage, and the finishing arc program is executed until the starting arc area 101 corresponding to the starting arc stage is covered to complete welding (the end position can be recorded as 368°), which can realize the smooth overlap of the finishing arc area 102 and the starting arc area 101 of the weld seam. The finishing arc time is 1000 ms, and the laser power is controlled to linearly decrease from 9.75 kW to 0 kW during the finishing arc stage; the welding of the entire pipeline butt joint is completed during one welding process.

[0131] Example 4

[0132] In this example, the test material is a GH3535 alloy pipeline with an outer diameter of 141.3 mm and a wall thickness of 9.1 mm.

[0133] There are differences in Steps 4 and 5 of the welding method from Example 2, and the remaining conditions are the same as those in Example 2. Specifically, Steps 4 and 5 are as follows:

[0134] Step 4: Select to use a fiber laser, adopt single-sided laser (the laser beam is vertically incident), and the laser welding energy parameters are set as: the spot diameter is 0.4 mm, and the laser power is 9.5 kW; the laser welding motion parameters are set as: the defocus amount is -5 mm, and the welding speed is 1.8 m / min.

[0135] Step 5: Weld according to the preset laser welding parameters. The welding direction is clockwise. This welding successively includes the starting arc stage, the welding stage, and the finishing arc stage according to the welding direction;

[0136] Among them, taking the starting position of welding as 0°, the laser power in the range of 8° - 344° is increased from 9.5 kW to 10 kW. The welding areas corresponding to the welding stage successively include the first flat welding area of 8° - 45°, the downward vertical welding area of 45° - 135°, the overhead welding area of 135° - 225°, the upward vertical welding area of 225° - 315°, and the second flat welding area of 315° - 344°. The laser power in the first flat welding area is gradually increased from 9.5 kW to 9.6 kW, the laser power in the downward vertical welding area is gradually increased from 9.6 kW to 9.8 kW, the laser power in the overhead welding area is gradually increased from 9.8 kW to 10 kW, and the laser power in the upward vertical welding area and the second flat welding area remains unchanged at 10 kW.

[0137] Among them, the starting arc area corresponding to the starting arc stage is 0° - 8°. In the starting arc stage, the starting arc program is executed until the end position of the starting arc area (denoted as 8°), the starting arc time is 800 ms, and the laser power is linearly increased from 0 kW to the welding power of 9.5 kW in the starting arc stage. When welding reaches the starting position of the finishing arc area (denoted as 344°), it enters the finishing arc stage. The finishing arc program is executed until the starting arc area corresponding to the starting arc stage is covered to complete welding (the end position can be denoted as 368°), which can achieve smooth lap joint between the finishing arc area and the starting arc area of the weld. The finishing arc time is 1000 ms, and the laser power is linearly decreased from 10 kW to 0 kW in the finishing arc stage. The welding of the entire pipeline butt joint is completed in one welding process.

[0138] Comparative Example 1

[0139] The difference between this comparative example and Example 2 is that in step 5, the laser power gradient is increased in the range of 8° - 344°, and the welding area is divided into two continuous areas. Correspondingly, the laser power is divided into 2 gradients in sequence. Specifically, the laser power in the area of 8° - 180° is 9.5 kW, and the laser power in the area of 180° - 344° is 10 kW; the starting arc time is 300 ms; the other conditions are the same as those in Example 2.

[0140] Comparative Example 2

[0141] The difference between this comparative example and Example 2 is as follows: In Step 5, the laser power within the range of 8° - 344° is gradually decreased from 10.7 kW to 10.5 kW in a gradient manner. The corresponding welding areas successively include the first flat welding area of 8° - 45°, the first downward vertical welding area of 45° - 90°, the second downward vertical welding area of 90° - 135°, the first overhead welding area of 135° - 180°, the second overhead welding area of 180° - 225°, the first upward vertical welding area of 225° - 270°, the second upward vertical welding area of 270° - 315°, and the second flat welding area of 315° - 344°. Accordingly, the laser power is successively divided into 8 gradients, and the step size of each gradient is 25 W; the arc starting time is 300 ms; other conditions are the same as those in Example 2.

[0142] Effect of Example 1

[0143] (1)X-ray detection

[0144] The internal volume defects of the circumferential welds of the nickel-based alloy pipes obtained by the welding processes of the nickel-based alloy pipes in the above Examples 1 - 4 and Comparative Examples 1 - 2 were respectively obtained through X-ray detection. The X-ray diagrams of the circumferential welds obtained by the welding method in Example 1 are as Figure 4 shown, and the X-ray diagrams of the circumferential welds obtained by the welding method in Example 3 are as Figure 8 shown.

[0145] Among them, the X-ray detection was carried out with reference to the American Society of Mechanical Engineers standard ASME BPVC-V-2017, and X-ray diagrams were obtained. Specifically, with the starting position of the welding as 0°, X-ray detections were respectively carried out on the circumferential welds in the regions of 0° - 45°, 45° - 90°, 90° - 135°, 135° - 180°, 180° - 225°, 225° - 270°, 270° - 315°, and 315° - 360°, namely (4), (3), (2), (1), (8), (7), (6), and (5).

[0146] (2)Forming pictures

[0147] The surfaces (front and back) of the circumferential welds of the nickel-based alloy pipes obtained by the welding processes of the nickel-based alloy pipes in the above Examples 1 - 4 and Comparative Examples 1 - 2 were photographed to obtain the front forming pictures and the back forming pictures respectively. The front forming pictures and the back forming pictures of Examples 1 - 4 and Comparative Examples 1 - 2 are respectively as Figures 5-7 and Figures 9-11As shown. Specifically, with the starting position of welding as 0°, the surface forming pictures are taken respectively for the circumferential welds at the positions of 0° - 45°, 45° - 90°, 90° - 135°, 135° - 180°, 180° - 225°, 225° - 270°, 270° - 315° and 315° - 360° for the front sides (A4), (A3), (A2), (A1), (A8), (A7), (A6) and (A5) and the back sides (a4), (a3), (a2), (a1), (a8), (a7), (a6) and (a5).

[0148] It can be seen from Figures 4-5 that for the weld front side obtained by using the welding method in Embodiment 1 of the present invention, there are no welding defects such as excessive height and humps, and there are also no forming defects such as collapse and weld bead on the weld back side, and the forming quality is relatively high. This welding method can achieve one-time forming of 5G all-position single-sided welding of pipeline butt joints without grooving, and effectively control the forming defects on the surface and inside of the weld caused by the serious oxidation problem in the high-power welding process. Correspondingly, the obtained nickel-based alloy pipeline joints have good mechanical and corrosion resistance properties. Among them, A4 corresponds to the overlapping part obtained at the arc starting and ending positions, and the forming quality of its surface and back side is also good.

[0149] It can be seen from Figure 6 that by using the laser welding method in Embodiment 2 of the present invention, for two GH3535 alloy pipelines with a length of 90 mm, an outer diameter of 141.3 mm and a wall thickness of 9.1 mm, it is possible to achieve one-time forming of 5G all-position single-sided welding of pipeline butt joints without grooving. There are no welding defects such as excessive height and humps on the weld front side, and there are also no forming defects such as collapse and weld bead on the weld back side, and the forming quality is relatively high. Correspondingly, the obtained nickel-based alloy pipeline joints have good mechanical and corrosion resistance properties.

[0150] Although there are small arc ending pit keyholes at the overlapping positions of the arc ending area and the arc starting area of the nickel-based alloy pipelines obtained in Embodiments 1 - 2, as shown in Figure 4 (4)、 Figure 5 (A4)、(a4)and Figure 6 (A4)、(a4), and there are a small amount of spatter and undercut defects on the front side, as shown in Figure 5 in (A5)、(A6)and Figure 6 in (A7)、(A6)、(A5), but there are no welding defects such as excessive height and humps on the weld front side, and there are also no forming defects such as collapse and weld bead on the weld back side. The overall forming quality is relatively high, which is better than that of Comparative Example 1 and Comparative Example 2.

[0151] It can be seen from Figures 7-9It can be seen that the front side of the weld obtained by using the welding method in Embodiments 3-4 of the present invention does not show welding defects such as undercut, excessive height, and hump, and the back side of the weld also does not show forming defects such as collapse and overlap bead, with relatively high forming quality. This welding method can achieve one-time forming of the 5G all-position single-sided welding of the pipeline butt joint without beveling, and effectively control the forming defects on the surface and inside of the weld caused by the serious oxidation problem in the high-power welding process. Among them, A4 corresponds to the overlapping part obtained at the starting and ending arc positions, and the forming quality of its front and back sides is also good.

[0152] Compared with Embodiments 1-2, the effect at the overlapping position of the starting and ending arc regions of the nickel-based alloy pipeline obtained in Embodiments 3-4 is better, there is no ending arc pit keyhole, and there are no spatter and undercut defects on the front side, and the overall forming quality is more excellent.

[0153] It can be seen from Figures 10-11 that for the nickel-based alloy pipeline welds obtained by the welding methods in Comparative Examples 1-2, either the front side of the weld shows welding defects such as undercut, excessive height, and hump, or the back side of the weld shows forming defects such as collapse and overlap bead, with relatively poor forming quality.

[0154] Although the specific implementation manners of the present invention have been described above, those skilled in the art should understand that this is only for illustration, and the protection scope of the present invention is defined by the appended claims. Without departing from the principle and essence of the present invention, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A welding method for a nickel-based alloy pipeline, characterized in that, It uses a 5G all-position laser welding method to weld the pipeline to be welded; Among them, the pipeline to be welded includes a butt-jointed first nickel-based alloy pipeline and a second nickel-based alloy pipeline, and the butt-joint of the first nickel-based alloy pipeline and the second nickel-based alloy pipeline is the welding surface to be welded; the welding surface to be welded is in an inert gas atmosphere, and the inert gas includes a front inert gas, a side inert gas and a back inert gas; The welding surface to be welded sequentially includes a flat welding area, a downward vertical welding area, an overhead welding area and an upward vertical welding area in the welding direction; Among them, the laser powers corresponding to the downward vertical welding area, the overhead welding area and the upward vertical welding area are sequentially increased.

2. The welding method of a nickel-based alloy pipeline according to claim 1, wherein The total increase value of the laser power is 0.3-1 kW, preferably 0.5-1 kW, for example 0.75 kW or 0.8 kW; And / or, the angles between the downward vertical welding area, the overhead welding area and the upward vertical welding area and the geometric center of the welding surface to be welded are equal; And / or, the angle between the flat welding area and the geometric center of the welding surface to be welded is 20°-100°, for example 90°; And / or, the angle between the downward vertical welding area and the geometric center of the welding surface to be welded is 20°-100°, for example 90°; And / or, the angle between the overhead welding area and the geometric center of the welding surface to be welded is 20°-100°, for example 90°; And / or, the angle between the upward vertical welding area and the geometric center of the welding surface to be welded is 20°-100°, for example 90°.

3. The welding method of the nickel-based alloy pipeline according to claim 1, characterized in that, The welding sequentially includes a starting arc stage, a welding stage and an arc extinguishing stage in the welding direction; the starting arc area corresponding to the starting arc stage and the arc extinguishing area corresponding to the arc extinguishing stage fall within the flat welding area, and the arc extinguishing area covers the starting arc area; the welding area corresponding to the welding stage includes the area outside the arc extinguishing area in the flat welding area, the downward vertical welding area, the overhead welding area and the upward vertical welding area; Preferably, the angle between the starting arc area and the geometric center of the welding surface to be welded is 5°-10°, for example 8°; Preferably, the angle between the arc extinguishing area and the geometric center of the welding surface to be welded is 15°-20°, for example 16°.

4. The welding method of the nickel-based alloy pipeline according to claim 3, characterized in that, The welding area includes a first flat welding area, a downward vertical welding area, an overhead welding area, an upward vertical welding area and a second flat welding area; The laser powers at the end positions of the first flat welding area, the downward vertical welding area, the overhead welding area, the upward vertical welding area and the second flat welding area are a1, b, c, d and a2 respectively, and they satisfy: a1 < b < c ≤ d ≤ a2; among them, the a1, b, c, d and a2 preferably satisfy one or more of the following conditions: (1) a2 - a1 is 0.3-1 kW, preferably 0.5-1 kW, for example 0.75 kW or 0.8 kW; (2) b - a1 is 0.1-0.3 kW, preferably 0.1-0.2 kW; (3) c - b is 0.1-0.3 kW, preferably 0.1-0.2 kW; (4) b - a1 = c - b; (5) c - a1 is 0.2 - 0.7 kW, for example 0.4 kW, 0.5 kW or 0.6 kW; (6) a2 - c is 0 - 0.1 kW, for example 0.05 kW; (7) The a1 is 9 - 12 kW, for example 9.5 kW; (8) The a2 is 9.3 - 13 kW, for example 10 kW or 9.75 kW; (9) The included angle between the first flat welding area and the geometric center of the surface to be welded is 35° - 40°, for example 37°; (10) The included angles of the downward vertical welding area, the overhead welding area and the upward vertical welding area with the geometric center of the surface to be welded are equal; (11) The included angle between the second flat welding area and the geometric center of the surface to be welded is 25° - 30°, for example 29°; 5. The welding method of the nickel-based alloy pipeline according to claim 3, characterized in that, The welding area includes a first flat welding area, a first downward vertical welding area, a second downward vertical welding area, a first overhead welding area, a second overhead welding area, a first upward vertical welding area, a second upward vertical welding area and a second flat welding area; The laser power corresponding to the first flat welding area, the first downward vertical welding area, the second downward vertical welding area, the first overhead welding area, the second overhead welding area, the first upward vertical welding area, the second upward vertical welding area and the second flat welding area is increased in a gradient manner; Among them, preferably, the included angle between the first flat welding area and the geometric center of the surface to be welded is 35° - 40°, for example 37°; Among them, preferably, the included angles of the first downward vertical welding area, the second downward vertical welding area, the first overhead welding area, the second overhead welding area, the first upward vertical welding area and the second upward vertical welding area with the geometric center of the surface to be welded are equal; Among them, preferably, the included angle between the second flat welding area and the geometric center of the surface to be welded is 25° - 30°, for example 29°; Among them, preferably, the gradient is an equal gradient; Among them, preferably, the step size of the gradient is 20 - 300 W, more preferably 20 - 150 W, for example 62.5 W, 75 W, 100 W, 125 W, 200 W or 250 W; Among them, preferably, the step size of each gradient is 125 W, and the total increase value of the laser power is 1 kW; Among them, preferably, the step size of each gradient is 62.5 W, and the total increase value of the laser power is 500 W.

6. The welding method of the nickel-based alloy pipeline according to claim 1, characterized in that, The material of the first nickel-based alloy pipe is nickel-chromium alloy, nickel-chromium-molybdenum alloy, nickel-chromium-iron alloy or nickel-chromium-molybdenum-iron alloy. The nickel-chromium-molybdenum-iron alloy is preferably Ni-16Mo-7Cr-4Fe, such as GH3535 alloy; And / or, the material of the second nickel-based alloy pipe is nickel-chromium alloy, nickel-chromium-molybdenum alloy, nickel-chromium-iron alloy or nickel-chromium-molybdenum-iron alloy. The nickel-chromium-molybdenum-iron alloy is preferably Ni-16Mo-7Cr-4Fe, such as GH3535 alloy; And / or, the outer diameter of the pipe to be welded is 130 mm - 200 mm, preferably 130 - 180 mm, for example 141.3 mm; And / or, the wall thickness of the pipe to be welded is 8 - 12 mm, for example 9.53 mm or 9.1 mm.

7. The welding method of the nickel-based alloy pipeline according to claim 1, characterized in that, The horizontal distance between the outlet of the side protective gas and the laser beam is 2-5 mm, preferably 2-3 mm; And / or, the vertical distance between the outlet of the front protective gas and the surface of the pipeline to be welded is 3-7 mm, preferably 3-5 mm; And / or, the diameter of the laser spot for welding is 0.1-0.4 mm; And / or, the defocus amount for welding is -1 to -10 mm, for example, -5 mm; And / or, the welding speed for welding is 1.8-3 m / min, for example, 2.4 m / min; And / or, the laser beam for welding is incident vertically.

8. The welding method of the nickel-based alloy pipeline according to claim 1, characterized in that, The method for preparing the pipeline to be welded includes the following steps: butt-joining and fixing a first nickel-based alloy pipeline and a second nickel-based alloy pipeline to obtain the pipeline to be welded; Wherein, after the butt-joining, the gap between the welding surfaces of the first nickel-based alloy pipeline and the second nickel-based alloy pipeline is preferably 0-0.1 mm, more preferably 0-0.05 mm; Wherein, after the butt-joining, the misalignment amount of the welding surfaces of the first nickel-based alloy pipeline and the second nickel-based alloy pipeline is preferably 0-1 mm; Wherein, preferably, a pretreatment step is further included before the butt-joining, and the pretreatment step includes the machining of the pipeline to be welded and the cleaning step of the pipeline to be welded; Wherein, the fixing method is preferably spot welding; wherein, the laser power for the spot welding is preferably 3-5 kW, for example, 3.5 kW; the light-emitting time for the spot welding is preferably 400-800 ms, for example, 600 ms.

9. The welding method for nickel-based alloy pipelines according to claim 1, wherein The types of the front protective gas, side protective gas and back protective gas are inert protective gases, preferably including one or more of nitrogen, argon and helium; And / or, the gas flow rate of the side protective gas is 3-15 L / min; And / or, the gas flow rate of the front protective gas is 30-45 L / min; And / or, before the welding is carried out, the gas flow rate of the back protective gas is 20-45 L / min; And / or, when the welding is carried out, the gas flow rate of the back protective gas is 3-5 L / min.

10. A nickel-based alloy pipeline, characterized in that, It is obtained by the welding method for nickel-based alloy pipelines according to any one of claims 1-9.

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