Titanium alloy pipe welding method

Abstract

The invention discloses a titanium alloy pipe welding method. The titanium alloy pipe welding method comprises the following steps that the two ends of a round pipe to be welded are covered with a first sealing cover and a second sealing cover correspondingly; a to-be-welded circular pipe is rotatably arranged on the support; the gas inlets in the welding gun, the dragging cover and the first sealing cover are connected with the corresponding gas channels correspondingly; a first aluminum foil adhesive tape and a second aluminum foil adhesive tape are respectively adhered to the bracket and the dragging cover; protective gas is input into the welding gun, the dragging cover and the round pipe to be welded through the corresponding gas channels; and after air in the to-be-welded round pipe is emptied, the to-be-welded round pipe is rotated, and formal welding is conducted in cooperation with a welding gun and a welding wire. Wherein the circular tube to be welded and the welding gun are arranged in an inclined mode by 60-80 degrees, the welding gun and the welding wire are arranged in an inclined mode by 80-90 degrees, and meanwhile, the welding gun, the welding wire and the center face of a welding seam are located on the same plane. The front face and the back face of the weld joint can be comprehensively and effectively protected during welding, welding defects can be reduced, and the welding quality is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a titanium alloy pipe welding method. Background Art

[0002] Titanium alloy materials have good characteristics of high temperature resistance, corrosion resistance, wear resistance, fatigue resistance, and lightweight. As a marine material, they have broad prospects. Due to the high chemical activity of titanium, ordinary arc welding, gas welding, and CO2 gas shielded welding cannot be used. At present, titanium alloy tubes use non-melting electrode argon arc welding gas to protect only the arc range, and other parts are in the air. When the welding arc moves forward, the weld is still in a high temperature state without argon protection. At this time, the weld is easily contaminated by air, moisture, and oxide scale, and impurities such as oxygen, nitrogen, hydrogen, and carbon are absorbed from the surface, causing the comprehensive mechanical properties of the material to deteriorate sharply, affecting the performance of its structure and failing to meet the use requirements. In order to correctly formulate the welding process of titanium alloys and improve the welding quality, it is necessary to have a deep understanding of the welding characteristics of titanium alloys. Therefore, it is urgent to invent a titanium alloy tube welding method to solve the above problems. Summary of the invention

[0003] The object of the present invention is to provide a titanium alloy pipe welding method, which can not only realize comprehensive and effective protection of the front and back sides of the weld during welding, but also reduce welding defects and ensure the quality of welding.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A titanium alloy tube welding method comprises the following steps:

[0006] Step S1: providing a bracket, a welding gun, a drag cover, a welding wire, a first aluminum foil tape, a second aluminum foil tape, a first sealing cover, a second sealing cover and two titanium alloy tubes;

[0007] Step S2: butting the two titanium alloy tubes and performing tack welding to form a round tube to be welded, respectively covering the two ends of the round tube to be welded with the first sealing cover and the second sealing cover, and respectively opening an air inlet and an air outlet on the first sealing cover and the second sealing cover;

[0008] Step S3: rotatably disposing one end of the round tube to be welded close to the second sealing cover on the bracket, wherein the bracket is provided with a socket for inserting the round tube to be welded;

[0009] Step S4: connecting the welding gun, the hood and the gas inlet to the first gas channel, the second gas channel and the third gas channel for inputting the shielding gas respectively;

[0010] Step S5: setting the drag cover on the outside of the circular tube to be welded, and the bottom of the drag cover is provided with an arc-shaped groove; bonding the first aluminum foil tape to the bracket, the first aluminum foil tape is set on the outer circumference of the circular tube to be welded and is not bonded to the circular tube to be welded, and the first aluminum foil tape is provided with a notch for exposing the weld; pasting the second aluminum foil tape on the gap formed between the arc-shaped groove and the circular tube to be welded, and the second aluminum foil tape is not bonded to the circular tube to be welded;

[0011] Step S6: introducing protective gas into the first gas channel, the second gas channel and the third gas channel respectively, so that the air in the circular tube to be welded is discharged from the exhaust port;

[0012] Step S7: After the air in the circular tube to be welded is exhausted, the welding gun is installed on the drag cover, the muzzle of the welding gun is pointed to the weld, and the welding wire is arranged on the outside of the circular tube to be welded; then, the circular tube to be welded and the welding gun are arranged at an angle α, the range of the angle α is 60 degrees to 80 degrees, and the welding gun and the welding wire are arranged at an angle β, the range of the angle β is 80 degrees to 90 degrees, and at the same time, the welding gun, the welding wire and the weld center plane of the circular tube to be welded are on the same plane; wherein the weld center plane is a plane formed by a line connecting the weld root and the midpoint of the weld surface, and the plane extends along the length direction of the weld;

[0013] Step S8: Continuously introduce shielding gas into the first gas channel, the second gas channel and the third gas channel, rotate the round tube to be welded, and then perform formal welding with the welding gun and the welding wire.

[0014] As a preferred embodiment of the present invention, in the step S2, before butting the two titanium alloy tubes and performing tack welding, a welding groove is processed at the butt joint between the two titanium alloy tubes.

[0015] As a preferred embodiment of the present invention, a plurality of positioning welds are provided on the weld of the circular tube to be welded, and the plurality of positioning welds are evenly spaced along the circumferential direction of the circular tube to be welded.

[0016] As a preferred embodiment of the present invention, the welding material used in the tack welding process is consistent with that used in the formal welding.

[0017] As a preferred embodiment of the present invention, in step S8, before formal welding, the welding groove and the oxidized portion of the welding wire are removed and cleaned.

[0018] As a preferred embodiment of the present invention, in step S8, when the arc is temporarily extinguished or welding is stopped during the formal welding process, the first gas channel, the second gas channel and the third gas channel stop introducing the shielding gas after a delay of 5 to 8 seconds.

[0019] As a preferred solution of the present invention, the protective gas introduced into the first gas channel, the second gas channel and the third gas channel is argon gas with a purity greater than 99.999%.

[0020] As a preferred solution of the present invention, in step S8, before formal welding, the gas shielding system of the welding torch is inspected using a titanium test plate.

[0021] As a preferred solution of the present invention, a pressure gauge and a flow meter are provided on the first gas channel, the second gas channel and the third gas channel.

[0022] As a preferred embodiment of the present invention, in step S6, before the shielding gas is introduced, a sponge block is inserted into the circular tube to be welded, and the sponge block is close to one side of the air inlet.

[0023] Compared with the prior art, the titanium alloy tube welding method provided by the present invention has the following beneficial effects:

[0024] (1) Before the formal welding, the two titanium alloy tubes are butt-jointed and tack-welded to form a circular tube to be welded, so that the welding part of the circular tube to be welded can be fixed in an appropriate position to ensure the accuracy and stability of the subsequent formal welding process; during the formal welding, the protective gas is introduced into the welding gun and the drag hood respectively through the first gas channel and the second gas channel, and the welding gun is used in conjunction with the welding wire to weld the weld of the circular tube to be welded, and the protective gas can be blown directly above the molten pool, so that an inert atmosphere is quickly formed near the front of the weld, and the cooling and solidification of the molten weld is accelerated; the protective gas is introduced into the circular tube to be welded through the third gas channel, so that the back of the weld in the tube can be fully protected to prevent oxidation of the back of the weld. At the same time, by setting the first aluminum foil tape and the second aluminum foil tape, the front of the weld of the circular tube to be welded can be always in a protected state, effectively preventing the rotating circular tube to be welded so that the welded area is exposed to the air and oxidized.

[0025] (2) During the formal welding, the welding gun and the round tube to be welded are arranged at an angle of 60 to 80 degrees, and the welding gun and the welding wire are arranged at an angle of 80 to 90 degrees. At the same time, the welding gun, the welding wire and the weld center plane of the round tube to be welded are located on the same plane, which can facilitate the observation of the fusion of the molten pool and the size of the weld, which is helpful for gas shielding the weld and can also make the weld beautiful. Otherwise, it will lead to poor gas protection and easily produce defects such as pores and weld deviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0027] Figure 1 It is a welding schematic diagram of a titanium alloy tube welding method provided by an embodiment of the present invention;

[0028] Figure 2 It is Figure 1 A cross-sectional view taken along line AA of the structure shown.

[0029] Markings in the figure:

[0030] 1. Bracket; 2. Welding gun; 3. Drag hood; 4. Welding wire; 5. First aluminum foil tape; 51. Notch; 6. Second aluminum foil tape; 7. First sealing cover; 71. Air inlet; 8. Second sealing cover; 81. Exhaust port; 9. Round tube to be welded; 10. First gas channel; 11. Second gas channel; 12. Third gas channel; 13. Pressure gauge; 14. Flow meter. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0032] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. It should be understood that the terms "first", "second", etc. are used in the present invention to describe various information, but such information should not be limited to these terms, which are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, "first" information may also be referred to as "second" information, and similarly, "second" information may also be referred to as "first" information.

[0033] See also Figure 1 to Figure 2 The preferred embodiment of the present invention provides a titanium alloy tube welding method, which comprises the following steps:

[0034] Step S1: providing a bracket 1, a welding gun 2, a drag cover 3, a welding wire 4, a first aluminum foil tape 5, a second aluminum foil tape 6, a first sealing cover 7, a second sealing cover 8 and two titanium alloy tubes;

[0035] Step S2: butting the two titanium alloy tubes and performing tack welding to form a round tube 9 to be welded, and respectively covering the two ends of the round tube 9 to be welded with the first sealing cover 7 and the second sealing cover 8, and respectively opening an air inlet 71 and an air outlet 81 on the first sealing cover 7 and the second sealing cover 8;

[0036] Step S3: rotatably disposing one end of the circular tube 9 to be welded close to the second sealing cover 8 on the bracket 1, wherein the bracket 1 is provided with an insertion hole for inserting the circular tube 9 to be welded;

[0037] Step S4: connecting the welding gun 2, the drag hood 3 and the gas inlet 71 to the first gas channel 10, the second gas channel 11 and the third gas channel 12 for inputting the shielding gas respectively;

[0038] Step S5: the drag cover 3 is arranged on the outer side of the circular tube 9 to be welded, and an arc-shaped groove is provided at the bottom of the drag cover 3; the first aluminum foil tape 5 is bonded to the bracket 1, the first aluminum foil tape 5 is arranged on the outer periphery of the circular tube 9 to be welded and is not bonded to the circular tube 9 to be welded, and a notch 51 for exposing the weld is provided on the first aluminum foil tape 5; the second aluminum foil tape 6 is bonded to the gap formed between the arc-shaped groove and the circular tube 9 to be welded, and the second aluminum foil tape 6 is not bonded to the circular tube 9 to be welded;

[0039] Step S6: introducing protective gas into the first gas channel 10, the second gas channel 11 and the third gas channel 12 respectively, so that the air in the circular tube 9 to be welded is discharged from the exhaust port 81;

[0040] Step S7: After the air in the circular tube 9 to be welded is exhausted, the welding gun 2 is installed on the drag cover 3, the muzzle of the welding gun 2 is pointed to the weld, and the welding wire 4 is arranged on the outside of the circular tube 9 to be welded; then, the circular tube 9 to be welded is arranged at an angle α with the welding gun 2, the angle α is in the range of 60 degrees to 80 degrees, and the welding gun 2 is arranged at an angle β with the welding wire 4, the angle β is in the range of 80 degrees to 90 degrees, and at the same time, the welding gun 2, the welding wire 4 and the weld center plane of the circular tube 9 to be welded are on the same plane; wherein the weld center plane is a plane formed by a line connecting the weld root and the midpoint of the weld surface, and the plane extends along the length direction of the weld;

[0041] Step S8: Continue to introduce shielding gas into the first gas channel 10 , the second gas channel 11 and the third gas channel 12 , rotate the round tube 9 to be welded, and then perform formal welding with the welding gun 2 and the welding wire 4 .

[0042] In the titanium alloy tube welding method of the present invention, before formal welding, the two titanium alloy tubes are butt-jointed and position-welded to form a circular tube 9 to be welded, and the welding part of the circular tube 9 to be welded can be fixed in an appropriate position to ensure the accuracy and stability of the subsequent formal welding process; during formal welding, protective gas is introduced into the welding gun 2 and the drag hood 3 respectively through the first gas channel 10 and the second gas channel 11, and the welding gun 2 cooperates with the welding wire 4 to weld the weld of the circular tube 9 to be welded, and the protective gas can be directly blown above the molten pool, so that an inert atmosphere is quickly formed near the front of the weld, and the cooling and solidification of the molten weld is accelerated; protective gas is introduced into the circular tube 9 to be welded through the third gas channel 12, which can achieve all-round protection of the back of the weld in the tube to prevent oxidation of the back of the weld. At the same time, by setting the first aluminum foil tape 5 and the second aluminum foil tape 6, the front of the weld of the circular tube 9 to be welded can be always in a protected state, effectively preventing the rotating circular tube 9 from exposing the welded area to the air and oxidizing. In addition, during formal welding, the welding gun 2 and the circular tube 9 to be welded are arranged at an angle of 60 to 80 degrees, and the welding gun 2 and the welding wire 4 are arranged at an angle of 80 to 90 degrees. At the same time, the welding gun 2, the welding wire 4 and the weld center planes of the circular tube 9 to be welded are located on the same plane, which makes it easy to observe the fusion of the molten pool size weld, helps gas shielded welds, and can also make the welds beautiful. Otherwise, it will lead to poor gas protection and easily produce defects such as pores and weld deviation.

[0043] Exemplarily, in order to improve the welding quality and strength, in the step S2, before the two titanium alloy tubes are butt-jointed and tack-welded, the welding groove is processed at the butt joint between the two titanium alloy tubes. When performing tack welding, a plurality of tack welds are provided on the weld of the circular tube 9 to be welded, and the plurality of tack welds are evenly spaced along the circumferential direction of the circular tube 9 to be welded. In this embodiment, the tack welding length is preferably 5 mm, and the tubes with a diameter of 8 to 38 mm are three-spot welds staggered by 120°, and the tubes with a diameter of 38 to 257 mm are four-spot welds staggered by 90°. Among them, the tack welds shall not have defects such as cracks, pores, slag inclusions, etc., otherwise they shall be removed and re-welded in time, and re-welding shall be performed in the nearby area; the tack welds shall remove the oxide layer on their surfaces, and make their two ends smoothly transition to facilitate arc connection, otherwise they shall be trimmed; to ensure the welding quality, the tack welding process shall be consistent with the welding materials used for formal welding.

[0044] For example, in step S8, before the formal welding, the weld groove and the oxidized part of the welding wire 4 are removed and cleaned. Such operation can effectively avoid defects such as pores, lack of fusion, slag inclusion, etc. during welding, and ensure the welding quality. In this embodiment: (1) the oil, water, dust and other dirt and oxide scale on the surface of the welding wire 4, the welding groove surface and the two sides within 20mm to 50mm should be removed. 5-10% sodium hydroxide solution or industrial propylene copper can be used to remove the residual grease and other dirt on the parent material and the surface of the welding wire 4, in order to remove the influence of carbon; (2) the cleaned welding wire 4 and weldment should be kept clean and dry to avoid re-contamination. The oxidized part of the end should be cut off. If there is oxidation on the surface of the welding wire 4, chemical cleaning should be carried out; (3) before welding, a stainless steel wire brush should be used to brush the parent material within at least 25mm from the edge of the weld, and clean it with a clean white silk cloth (cotton cloth or cotton yarn shall not be used) and acetone to remove all water rust, paint, dirt, metal powder, dust and other debris. The end face of the welding groove should be flat, and no cracks, burrs, pits, scratches and other defects are allowed. Welding should be carried out within 4 hours after cleaning, otherwise it should be cleaned again.

[0045] For example, in step S8, when the arc is temporarily extinguished or welding is stopped during the formal welding process, the first gas channel 10, the second gas channel 11 and the third gas channel 12 are delayed for 5 to 8 seconds before stopping the introduction of the shielding gas. Such an operation can ensure that the welding pool can still be fully protected even if the arc is extinguished or welding is stopped during the welding process, thereby improving the welding quality.

[0046] Exemplarily, the shielding gas introduced into the first gas channel 10, the second gas channel 11 and the third gas channel 12 is argon gas with a purity greater than 99.999%, which can reduce welding defects, reduce impurity content, and improve welding quality.

[0047] Exemplarily, in step S8, before formal welding, the gas shielding system of the welding torch is checked using a titanium test plate. If the weld surface is smooth and free of oxidation color, and the surfaces of the titanium test plates on both sides of the weld maintain a silvery luster, it means that the gas shielding system is working properly, the coverage of the shielding gas is good, the welding environment meets the requirements, and the inspection result is qualified; if oxidation color (such as blue, purple or yellow) appears on the weld surface, or obvious oxidation marks appear on the surfaces of the titanium test plates on both sides of the weld, it means that there is a problem with the gas shielding system, the coverage of the shielding gas is not good, the welding environment is polluted, and the inspection result is unqualified, then it is necessary to check whether the purity and flow of the shielding gas meet the requirements and whether there is leakage or blockage in the gas channel, and clean the welding wire 44 and retest until the inspection result is qualified.

[0048] Exemplarily, in order to better control the input of the protective gas, a pressure gauge 13 and a flow meter 14 are provided on the first gas channel 10 , the second gas channel 11 and the third gas channel 12 .

[0049] Exemplarily, in step S6, before the shielding gas is introduced, a sponge block is inserted into the circular tube 9 to be welded, and the sponge block is close to the side of the air inlet 71. Thus, the provision of the sponge block enables the shielding gas to be evenly filled in the circular tube 9 to be welded, forming an inert atmosphere.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A titanium alloy tube welding method, characterized in that: The steps include: Step S1: providing a bracket, a welding gun, a drag cover, a welding wire, a first aluminum foil tape, a second aluminum foil tape, a first sealing cover, a second sealing cover and two titanium alloy tubes; Step S2: butting the two titanium alloy tubes and performing tack welding to form a round tube to be welded, respectively covering the two ends of the round tube to be welded with the first sealing cover and the second sealing cover, and respectively opening an air inlet and an air outlet on the first sealing cover and the second sealing cover; Step S3: rotatably disposing one end of the round tube to be welded close to the second sealing cover on the bracket, wherein the bracket is provided with a socket for inserting the round tube to be welded; Step S4: connecting the welding gun, the hood and the gas inlet to the first gas channel, the second gas channel and the third gas channel for inputting the shielding gas respectively; Step S5: setting the drag cover on the outside of the circular tube to be welded, and the bottom of the drag cover is provided with an arc-shaped groove; bonding the first aluminum foil tape to the bracket, the first aluminum foil tape is set on the outer circumference of the circular tube to be welded and is not bonded to the circular tube to be welded, and the first aluminum foil tape is provided with a notch for exposing the weld; pasting the second aluminum foil tape on the gap formed between the arc-shaped groove and the circular tube to be welded, and the second aluminum foil tape is not bonded to the circular tube to be welded; Step S6: introducing protective gas into the first gas channel, the second gas channel and the third gas channel respectively, so that the air in the circular tube to be welded is discharged from the exhaust port; Step S7: After the air in the circular tube to be welded is exhausted, the welding gun is installed on the drag cover, the muzzle of the welding gun is pointed to the weld, and the welding wire is arranged on the outside of the circular tube to be welded; then, the circular tube to be welded and the welding gun are arranged at an angle α, the range of the angle α is 60 degrees to 80 degrees, and the welding gun and the welding wire are arranged at an angle β, the range of the angle β is 80 degrees to 90 degrees, and at the same time, the welding gun, the welding wire and the weld center plane of the circular tube to be welded are on the same plane; wherein the weld center plane is a plane formed by a line connecting the weld root and the midpoint of the weld surface, and the plane extends along the length direction of the weld; Step S8: Continuously introduce shielding gas into the first gas channel, the second gas channel and the third gas channel, rotate the round tube to be welded, and then perform formal welding with the welding gun and the welding wire.

2. The titanium alloy tube welding method according to claim 1, characterized in that: In the step S2, before butting the two titanium alloy tubes and performing tack welding, a welding groove is processed at the butt joint between the two titanium alloy tubes.

3. The titanium alloy tube welding method according to claim 2, characterized in that: A plurality of positioning welds are arranged on the weld of the circular tube to be welded, and the plurality of positioning welds are evenly spaced along the circumferential direction of the circular tube to be welded.

4. The titanium alloy tube welding method according to any one of claims 1 to 3, characterized in that: The welding materials used in positioning welding are consistent with those used in formal welding.

5. The titanium alloy tube welding method according to claim 2, characterized in that: In the step S8, before the formal welding, the welding groove and the oxidized part of the welding wire are removed and cleaned.

6. The titanium alloy tube welding method according to claim 1, characterized in that: In the step S8, when the arc is temporarily extinguished or welding is stopped during the formal welding process, the first gas channel, the second gas channel and the third gas channel stop introducing the shielding gas after a delay of 5 to 8 seconds.

7. The titanium alloy tube welding method according to claim 1, characterized in that: The protective gas introduced into the first gas channel, the second gas channel and the third gas channel is argon gas with a purity greater than 99.999%.

8. The titanium alloy tube welding method according to claim 1, characterized in that: In step S8, before formal welding, the gas shielding system of the welding torch is inspected using a titanium test plate.

9. The titanium alloy tube welding method according to claim 1, characterized in that: The first gas channel, the second gas channel and the third gas channel are all provided with a pressure gauge and a flow meter.

10. The titanium alloy tube welding method according to claim 1, characterized in that: In the step S6, before the shielding gas is introduced, a sponge block is inserted into the circular tube to be welded, and the sponge block is close to one side of the gas inlet.

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