A high alloy large diameter pipeline welding method and argon filling protection device

Abstract

The present invention relates to a high-alloy large-diameter pipeline welding method and an argon filling protection device thereof, which comprises: a V-shaped air chamber, an electromagnet and a power cord; the V-shaped air chamber as a whole is an arc-shaped structure matching the pipeline, and the two ends of the V-shaped air chamber are not connected. The cross-sectional structure of the V-shaped air chamber comprises a V-shaped portion, a first side edge, a second side edge and a shaping strip, the first side edge and the second side edge are respectively connected to the left and right sides of the upper edge of the V-shaped portion, and the first side edge and the second side edge are both perpendicular to the vertical center axis of the V-shaped portion. The shaping strip is an arc-shaped structure with the same curvature as the first side edge and the second side edge, and is fixed on the lower surface of the side edge. A plurality of electromagnets are evenly fixed on the lower surfaces of the first side edge and the second side edge, and each electromagnet is connected to a power cord. The device can effectively solve the problem that a special air chamber needs to be made for GTAW back-side argon filling welding of large-diameter pipelines, and argon needs to be continuously provided, which is easy to block the valve during the operation of the unit.

Description

Technical Field

[0001] The invention relates to the technical field of high-alloy large-diameter pipeline welding, and in particular to a high-alloy large-diameter pipeline welding method and an argon filling protection device thereof. Background Art

[0002] The information disclosed in the background of the invention is only intended to enhance the understanding of the overall background of the invention and should not be necessarily regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] During the welding process of certain pipes with high alloy content, it is necessary to adopt the method of back-filling argon to ensure that the welding on the back of the weld is not oxidized to ensure the welding quality. The conventional welding method is to fill the entire pipeline with argon, or use water-soluble paper or cardboard to stick and fix it in the pipeline to make a closed air chamber of about 20 cm filled with argon, and continue to maintain the flow rate of argon to ensure the purity of argon until the base layer welding is completed. However, the existing problems with this type of method are: (1) The method is complicated to operate, time-consuming and labor-intensive. (2) This method cannot ensure the tightness of the air chamber and there is a risk of leakage. (3) This method wastes argon very seriously. (4) The air chamber made by this method cannot be recycled, which is easy to cause valve blockage during the unit trial operation, requiring the unit to be shut down for maintenance, which consumes a lot of manpower and material resources. Summary of the invention

[0004] In view of the above-mentioned shortcomings, the present invention provides a high-alloy large-diameter pipeline welding method and an argon filling protection device thereof, which can effectively solve the problems that the back-side argon filling welding of large-diameter pipelines GTAW requires the preparation of a special gas chamber and the continuous supply of argon gas, which is easy to block the valve during the operation of the unit, and is not conducive to saving construction costs, energy conservation and environmental protection, and low construction efficiency. In order to achieve the above-mentioned invention purpose, the technical means adopted by the present invention are as follows.

[0005] First, the present invention discloses an argon-filled protective device for welding high-alloy large-diameter pipelines, comprising: a V-shaped air chamber, an electromagnet and a power cord; wherein the V-shaped air chamber as a whole is an arc-shaped structure that matches the pipeline, and the two ends of the V-shaped air chamber are not connected. The cross-sectional structure of the V-shaped air chamber includes a V-shaped portion, a first side edge, a second side edge and a shaping strip, wherein the first side edge and the second side edge are respectively connected to the left and right sides of the upper edge of the V-shaped portion, and the first side edge and the second side edge are both perpendicular to the vertical center axis of the V-shaped portion. The shaping strip is an arc-shaped structure with the same curvature as the first side edge and the second side edge, and is fixed on the lower surface of the side edge. A plurality of the electromagnets are evenly fixed on the lower surfaces of the first side edge and the second side edge, and each electromagnet is connected to the power cord.

[0006] Furthermore, the V-shaped portion, the first side edge, and the second side edge are all made of refractory graphite felt, which has good high temperature resistance and is easy to adapt to the high temperature environment caused by welding.

[0007] Furthermore, the shaping strip is a steel strip, which is fixed to the lower surface of the side edge by screwing or riveting. Preferably, there are two steel strips, which are fixed to the lower surface of the first side edge and the lower surface of the second side edge respectively. The steel strip is used to form a circular arc structure of the non-rigid refractory graphite felt so as to match the circular cross-sectional shape of the pipeline.

[0008] Optionally, each of the steel strips is composed of two semicircular steel strips, and the two semicircular steel strips are connected at the connection point by an elastic steel strip 9, so as to better ensure the curvature and deviation of the air chamber.

[0009] Furthermore, the electromagnet is fixed in the opening on the shaping strip to ensure the firmness of the electromagnet.

[0010] Furthermore, the side edge of the electromagnet is thinned to ensure the suction force of the electromagnet.

[0011] Furthermore, the total width of the V-shaped air chamber is 110-150 mm, wherein the widths of the first side edge and the second side edge are both 30-45 mm, and the depth / height of the V-shaped portion is 15-20 mm.

[0012] Furthermore, it also includes a main power line, and the power line connected to each electromagnet is connected to the main power line.

[0013] Furthermore, it also includes a pulling rope connected to the V-shaped air chamber and parallel to the power line, preferably a thin steel wire rope, so as to pull out the V-shaped air chamber from the power line side of the pipeline after welding is completed.

[0014] Secondly, the present invention discloses a high-alloy large-diameter pipeline welding method, comprising the following steps:

[0015] (1) Place the above-mentioned protective device into a pipeline, with the V-shaped portion located below the groove of the pipeline, and the first side edge and the second side edge located on both sides of the groove of the pipeline, so that the V-shaped air chamber covers the welding part of the pipeline; then energize the electromagnet to make it tightly adsorbed on the inner wall of the pipeline, and detect the air tightness of the V-shaped air chamber. After no problem, disconnect the power supply of the electromagnet, dock the two ends of the V-shaped air chamber and leave a gap, and then energize the electromagnet again to make it tightly adsorbed on the inner wall of the pipeline to complete the closure of the air chamber.

[0016] (2) Use argon arc welding for base welding. During welding, place the welding gun at the groove to allow argon to be filled into the groove to meet the argon flow and purity requirements of the gas chamber on the back of the weld before welding.

[0017] (3) When starting welding, place the welding wire in the gap of the groove, and keep the welding gun at a set angle to the direction of welding until the welding is completed.

[0018] Furthermore, in step (2), the forward gas supply time of the welding gun is not less than 60s.

[0019] Furthermore, in step (2), the welding gun stays at the groove for 20s-30s.

[0020] Furthermore, in step (2), the set angle is between 60° and 70°, which is conducive to blowing argon gas onto the weld to form protection and avoid oxidation on the back of the weld.

[0021] Furthermore, in step (2), the groove can be sealed from the outer surface of the pipe with tape before welding, leaving only an area of ​​100mm-200mm in length along the welding direction. During the welding process, a small amount of tape is removed and welding is immediately carried out until the entire process is completed. This ensures the airtightness of the gas chamber and the purity of the argon protection on the back of the weld.

[0022] Compared with the prior art, the beneficial technical effects achieved by the present invention mainly include the following parts:

[0023] (1) When argon arc welding is used to prime the joints of high-alloy large-diameter pipes, the V-shaped gas chamber is small and closed, which not only helps to prevent the loss of argon gas, but also can use the back-blowing effect of the argon gas flow in the welding gun to protect the molten pool on the back of the weld. Therefore, even if direct welding is performed, it will not cause oxidation and slag on the back of the base weld, thus ensuring the welding quality, saving the amount of argon gas and improving the construction efficiency.

[0024] (2) When the protective device of the present invention is used, after welding is completed, it is only necessary to disconnect the power supply of the electromagnet, and then pull out the V-shaped air chamber from the power line side of the pipeline. Since the inner wall of the pipeline is smooth, it will not form an obstacle when the air chamber is pulled out, thereby solving the problem that the air chamber made by the existing method cannot be recycled, which easily causes valve blockage during the trial operation of the unit, requiring the unit to be shut down for maintenance, which consumes a lot of manpower and material resources.

[0025] (3) The protective device of the present invention can save a large amount of argon gas, improve construction progress, save labor costs, ensure the tightness of the gas chamber, improve welding quality, and the protective device can be reused, which is energy-saving and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0027] Figure 1It is a cross-sectional view of an argon filling protection device for high alloy large diameter pipeline welding in an embodiment of the present invention.

[0028] Figure 2 1 is a top view of the side edge in an embodiment of the present invention.

[0029] Figure 3 It is a schematic diagram of the structure of the argon filling protection device for high alloy large diameter pipeline welding in an embodiment of the present invention.

[0030] The marks in the above drawings represent respectively: 1-V-shaped air chamber, 1.1-V-shaped portion, 1.2-first side edge, 1.3-second side edge, 1.4-forming strip; 2-electromagnet; 3-power cord; 4-main power cord; 5-pipeline; 6-groove; 7-welding gun; 8-welding wire; 9-elastic steel belt. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element needs to have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0034] Terminology explanation section: The terms "install", "connect", "connect", "fixed" and the like in the present invention should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral whole; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements, or an interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0035] refer to Figure 1-3, an example of a high alloy large diameter pipeline welding argon filling protection device, comprising: a V-shaped gas chamber 1, an electromagnet 2, a power line 3 and a main power line 4; wherein:

[0036] The V-shaped air chamber 1 is an arc-shaped structure that matches the pipeline as a whole, and the two ends of the V-shaped air chamber 1 are not connected. Specifically, the cross-sectional structure of the V-shaped air chamber 1 includes: a V-shaped portion 1.1, a first side edge 1.2, a second side edge 1.3 and a shaping strip 1.4. The first side edge 1.2 and the second side edge 1.3 are respectively connected to the left and right sides of the upper edge of the V-shaped portion 1.1, and the first side edge 1.2 and the second side edge 1.3 are both perpendicular to the vertical center axis of the V-shaped portion 1.1.

[0037] The V-shaped portion 1.1, the first side edge 1.2, and the second side edge 1.3 are all made of refractory graphite felt, which has good high temperature resistance and is easy to adapt to the high temperature environment caused by welding. The shaping strip 1.4 is an arc-shaped structure with the same arc as the first side edge 1.2 and the second side edge 1.3, and is fixed on the lower surface of the side edge.

[0038] The main function of the electromagnet 2 is to fix the V-shaped air chamber 1 tightly on the inner wall of the pipe to ensure the tightness of the air chamber. A plurality of electromagnets 2 are evenly fixed on the lower surface of the first side edge 1.2 and the second side edge 1.3, and each electromagnet 2 is connected to the power line 3, and the power line 3 connected to each electromagnet 2 is connected to the main power line 4.

[0039] Furthermore, in some other embodiments, the shaping strip 1.4 is a steel strip, and there are two steel strips, which are respectively fixed on the lower surfaces of the first side edge 1.2 and the second side edge 1.3. Each of the steel strips is composed of two semicircular steel strips, and the two semicircular steel strips are connected at the connection point by a 0.2 mm thick elastic steel strip 9 to better ensure the curvature and deviation of the air chamber. The steel strip is used to form a circular arc structure of the non-rigid refractory graphite felt to match the circular cross-sectional shape of the pipe.

[0040] Furthermore, in another embodiment, the electromagnet 2 is fixed on the opening of the shaping strip 1.4 to ensure the firmness of the electromagnet 2.

[0041] Furthermore, in another embodiment, the side edge of the electromagnet 2 is thinned to ensure the suction force of the electromagnet 2 .

[0042] Further, in another embodiment, the protection device of the above embodiment is used to weld a high-alloy large-diameter pipe, wherein the total width of the V-shaped air chamber 1 is 120 mm, wherein the widths of the first side edge 1.2 and the second side edge 1.3 are both 40 mm, and the depth / height of the V-shaped portion 1.1 is 15 mm. Specifically, the welding process includes the following steps:

[0043] (1) The grooves 6 of the two sections of the pipe 5 to be welded are butted together and the pipes are fixed to prevent the pipes from moving or dislocating during welding. Then the above-mentioned protective device is placed in the pipe, and the V-shaped portion 1.1 is located below the groove of the pipe, and the first side edge 1.2 and the second side edge 1.3 are located on both sides of the groove 6 of the pipe 5, so that the V-shaped air chamber 1 covers the welding part of the pipe. Then, the electromagnet 2 is energized to make it tightly adsorbed on the inner wall of the pipe, and the air tightness of the V-shaped air chamber 1 is tested. If there is no problem, the power supply of the electromagnet 2 is disconnected, and the two ends of the V-shaped air chamber 1 are butted together to leave a gap, and then the electromagnet 2 is energized again to make it tightly adsorbed on the inner wall of the pipe to complete the closure of the air chamber.

[0044] (2) Before welding, the groove 6 can be sealed from the outer surface of the pipe with tape, leaving only an area of ​​100mm-200mm in length along the welding direction. During the welding process, a small amount of tape is removed and welding is immediately completed until it is all completed. This ensures the airtightness of the gas chamber and the purity of the argon protection on the back of the weld.

[0045] (3) Use argon arc welding for base welding, set the forward gas supply time of welding gun 7 to 60s, and place welding gun 7 at groove 6 for 30s during welding to fill the groove with argon to achieve the argon gas flow and purity requirements of the gas chamber on the back of the weld before welding.

[0046] (4) When welding begins, the welding wire 8 is placed in the gap of the groove 6. This is to prevent part of the welding arc from damaging the V-shaped gas chamber. The angle between the welding gun and the welding direction is maintained between 60° and 70°. This is conducive to blowing argon gas onto the weld to form protection and avoid oxidation on the back of the weld until welding is completed.

[0047] When argon arc welding is used for base welding, since the V-shaped gas chamber is small and closed, it is not conducive to the loss of argon gas. The backblowing effect of the argon gas flow in the welding gun can be used to protect the molten pool on the back of the weld. Direct welding will not cause oxidation and slag on the back of the base weld, thereby ensuring the welding quality, saving argon gas consumption and improving construction efficiency. After welding, it is only necessary to cut off the power supply of the electromagnet and pull the V-shaped gas chamber out of the power line side of the pipeline through the wire rope. Since the inner wall of the pipeline is smooth, it will not form an obstacle when the special gas chamber is pulled out, thus avoiding the problem that the gas chamber made by the existing method cannot be recycled, which is easy to cause valve blockage during the unit trial operation, requiring the unit to be shut down for maintenance, and consuming a lot of manpower and material resources.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An argon-filled protection device for high-alloy large-diameter pipeline welding, characterized in that: include: The V-shaped air chamber is an arc-shaped structure that matches the pipeline, and the two ends of the V-shaped air chamber are not connected; The cross-sectional structure of the V-shaped air chamber comprises: a V-shaped portion, a first side edge, a second side edge and a shaping strip, wherein: the first side edge and the second side edge are respectively connected to the left and right sides of the upper edge of the V-shaped portion, and the first side edge and the second side edge are both perpendicular to the vertical center axis of the V-shaped portion; the shaping strip is an arc-shaped structure with the same curvature as the first side edge and the second side edge, and is fixed on the lower surface of the first side edge and the second side edge; Electromagnets, a plurality of electromagnets are evenly fixed on the lower surfaces of the first side edge and the second side edge; A power cord, each of the electromagnets is connected to the power cord; The electromagnet is fixed in the opening on the shaping strip; The side edge of the electromagnet is thinned.

2. The argon-filling protection device for high-alloy large-diameter pipeline welding according to claim 1 is characterized in that: The V-shaped portion, the first side edge and the second side edge are all made of refractory graphite felt.

3. The argon-filling protection device for high-alloy large-diameter pipeline welding according to claim 1 is characterized in that: The shaping strip is a steel strip, which is fixed to the lower surface of the side edge by screwing or riveting.

4. The argon-filling protection device for high-alloy large-diameter pipeline welding according to claim 3 is characterized in that: The steel strips are two in number and are respectively fixed on the lower surfaces of the first side edge and the second side edge.

5. The argon-filling protection device for high-alloy large-diameter pipeline welding according to claim 4 is characterized in that: Each of the steel strips is composed of two semicircular steel strips, and the two semicircular steel strips are connected at the connection point by an elastic steel strip.

6. The argon-filling protection device for high-alloy large-diameter pipeline welding according to any one of claims 1 to 4, characterized in that: The total width of the V-shaped air chamber is 110-150 mm, wherein the widths of the first side edge and the second side edge are both 30-45 mm, and the depth / height of the V-shaped portion is 15-20 mm.

7. The argon-filling protection device for high-alloy large-diameter pipeline welding according to any one of claims 1 to 4, characterized in that: It also includes a main power line, and the power line connected to each electromagnet is connected to the main power line.

8. The argon-filling protective device for high-alloy large-diameter pipeline welding according to any one of claims 1 to 4, characterized in that: The utility model also comprises a pulling rope connected to the V-shaped air chamber and parallel to the power line.

9. The argon-filling protection device for high-alloy large-diameter pipeline welding according to claim 8 is characterized in that: The pulling rope is a thin steel wire rope.

10. A high alloy large diameter pipeline welding method, characterized in that: The high alloy large diameter pipeline welding argon filling protection device according to any one of claims 1 to 5 is used to perform the process, comprising the following steps: (1) Place the above-mentioned protective device into a pipeline, with the V-shaped portion located below the groove of the pipeline, and the first side edge and the second side edge located on both sides of the groove of the pipeline, so that the V-shaped air chamber covers the welding part of the pipeline; then energize the electromagnet to make it tightly adsorb on the inner wall of the pipeline, and detect the air tightness of the V-shaped air chamber. After no problem, disconnect the power supply of the electromagnet, dock the two ends of the V-shaped air chamber and leave a gap, and then energize the electromagnet again to make it tightly adsorb on the inner wall of the pipeline to complete the closure of the air chamber; (2) Use argon arc welding to prime, and place the welding gun at the groove during welding; (3) When starting welding, place the welding wire in the gap of the groove, and keep the welding gun at a set angle to the direction of welding until the welding is completed.

11. The high alloy large diameter pipeline welding method according to claim 10, characterized in that: In step (2), the forward gas supply time of the welding gun is not less than 60s.

12. The high alloy large diameter pipeline welding method according to claim 10, characterized in that: In step (2), the welding gun stays at the groove for 20s-30s.

13. The high alloy large diameter pipeline welding method according to claim 10, characterized in that: In step (2), the set angle is between 60° and 70°.

14. The high alloy large diameter pipeline welding method according to any one of claims 10 to 13, characterized in that: In step (2), before welding, the groove is sealed from the outer surface of the pipe with tape, leaving only an area of ​​100mm-200mm in length along the welding direction. During the welding process, part of the tape is removed and welding is immediately continued until the entire area is completed.

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