Flexible protection tool for back of argon arc welding seam and manufacturing method thereof

Abstract

The application discloses an argon arc welding seam back flexible protection tool and a manufacturing method thereof. The tool comprises a shell, a bottom cover, a breather pipe, a rack, tin paper and a steel wire mesh. The shell extends along the welding seam to form a continuous, circumferentially closed and axially open space region, and the bottom cover is connected to and seals the first axially open end surface of the shell. The breather pipe penetrates through the bottom cover, and one end of the breather pipe is located in the space region formed by the shell. A plurality of racks are distributed on the outer side of the shell along the circumferential direction to form a flexible framework of a windproof screen. The tin paper covers the two surfaces of the racks, which are opposite to the welding seam back and away from the welding seam back. The steel wire mesh is arranged in the space region formed by the shell. The protection tool can be manufactured and adjusted on site according to the shape characteristics of the parts to be welded, ensures close contact with the welding seam back before welding, forms a gap with almost consistent size during the welding process, thereby forming a stable protection gas flow field and improving the surface quality after welding.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of argon arc welding of titanium alloy, high-temperature alloy and stainless steel, and particularly relates to a flexible protection tool for the back of an argon arc welding seam and a manufacturing method thereof. BACKGROUND

[0002] As a main welding method in the fields of aviation, aerospace, ship, automobile and chemical industry, the quality of a welding seam determines the quality of a product.

[0003] In actual production, the back of the welding seam is not well protected, and the molten metal and the surrounding air interact intensively, so that the content of oxygen and nitrogen in the welding seam metal increases. At the same time, the elements such as manganese and carbon decrease due to burning loss and evaporation, which causes the plasticity and toughness of the welding seam metal to sharply decrease. In order to improve the quality of the welding seam metal, the content of harmful impurities in the welding seam should be reduced as much as possible, and the burning loss of beneficial alloy elements should be reduced, so that the welding seam metal can have a proper chemical composition. Therefore, the metal in the welding area should be protected to prevent the molten pool metal from being affected by oxidation, nitriding and other air effects.

[0004] The fatigue behavior of the welding seam is greatly related to the appearance of the welding seam. Generally speaking, the greater the degree of geometric size mutation, the lower the fatigue strength. For argon arc welding, if the back of the welding seam is not well protected, the metal compounds formed by oxidation become inclusions in the welding seam, and the inclusions affect the turbulent effect of the fluid driving force (buoyancy, Lorentz force, shear stress caused by the surface tension gradient of the molten pool, shear stress caused by the action of the arc plasma on the surface of the molten pool) in the molten pool, which causes the back of the welding seam to be uneven and the shape to be sharp, and forms a serious notch effect.

[0005] The product of an aero-engine has a very high requirement for cleanliness. If the welding seam is seriously oxidized, the surface oxide layer will form a redundant material in the subsequent vibration process, which affects the use of the engine system.

[0006] The welding of a thin plate belongs to the welding of a deformable component. When the tooling design is unreasonable, a method of hand-holding a gas pipe for tracking protection is used in production. The general operation mode is that a welder performs flat position welding from the front, and a sheet metal worker looks up at the molten pool and synchronously tracks argon. The operation is not only inconvenient, but also causes the eyes to be burned by the arc for a long time, which leads to photophthalmia. In addition, two people are needed to perform welding on one welding seam, which consumes a large amount of labor.

[0007] As a solution, the welding protection blanket is a flexible welding protection device that can isolate and protect the welding seam. However, the protection blanket has a problem, that is, the protection of the back of the welding seam. Because of the welding position and the installation position of the protection blanket, the protection blanket will contact the welding pool, high-temperature reaction will form inclusions, and the glass fiber on the protection blanket will fall into the container to form a redundant material after long-term use. The welding of a product with high cleanliness requirement cannot meet the demand.

[0008] In order to overcome the above problems, the general solution is to improve the structure of the welding protection tooling, but there is a major problem in the design of the protection tooling, that is, the deformation of the sheet during welding occurs synchronously with the welding, and the welding deformation of the part cannot be accurately predicted at the beginning. When the weld is long or the welding needs to be implemented multiple times and cannot be completed at one time, the current protection tooling is designed according to the ideal state of the part after welding, which leads to uneven gaps in the tooling that cannot adapt to the deformation during the entire welding process, and uneven gaps can cause uneven distribution of protective gas and form turbulent flow, thereby introducing air to cause local oxidation of the weld, and cannot completely isolate and protect the back of the weld. SUMMARY

[0009] In view of the problems in the background art, the present application aims to provide an argon arc welding weld back flexible protection tooling and a manufacturing method thereof. The wind shield of the tooling can adjust the shape in time according to the welding deformation of the part, ensure that the wind shield can tightly adhere to the back of the weld before each welding, and form a stable protective gas flow field with the back of the weld during the welding process, avoid the introduction of air from the outside environment due to the disorder of the flow field, solve the problem of weld oxidation, and improve the production efficiency and product quality. In addition, the tooling is easy to manufacture and has strong adjustability, can be processed according to the shape characteristics of the weld, has low material requirements, and the manufacturing process is simple.

[0010] To solve the above problems, the present application adopts the following solutions:

[0011] The argon arc welding weld back flexible protection tooling comprises,

[0012] A shell, the shell extends along the weld direction to form a continuous, circumferentially closed, axially open space region, and the back of the weld is completely located in the space region;

[0013] A bottom cover, the bottom cover is connected and sealed to the first axially open end surface of the shell;

[0014] An air pipe, the air pipe passes through the bottom cover, and one end of the air pipe is located in the space region formed by the shell, and the other end is in communication with a protective gas source;

[0015] A rack, a plurality of racks are distributed on the outer side of the shell along the circumference of the shell to form a flexible skeleton of the wind shield, one end of the rack is connected at the second axially open end surface of the shell, and the other end extends away from the shell;

[0016] Tinfoil, the tinfoil covers the two surfaces of the rack facing the back of the weld and facing away from the back of the weld.

[0017] Further, the flexible protection tool for the back of the argon arc welding seam further comprises a steel wire mesh, at least one layer of the steel wire mesh is arranged in the space region formed by the shell, and the steel wire mesh covers one end of the vent pipe located in the shell, and the mesh holes of the steel wire mesh are not parallel to the axial direction.

[0018] Further, the connection between the bottom cover and the axially open end surface of the shell is covered with tin paper.

[0019] Further, the vent pipe is provided with exhaust holes at one end of the shell, and the exhaust holes are uniformly distributed on the circumferential surface of the vent pipe.

[0020] Further, the junction between the vent pipe and the bottom cover is covered with tin paper.

[0021] Further, the vent pipe is provided with a top cover at the end surface of one end of the shell.

[0022] Further, the rack is rectangular, the sizes of adjacent racks are the same, and the intervals between adjacent racks are equal.

[0023] The manufacturing method of the flexible protection tool for the back of the argon arc welding seam comprises,

[0024] The manufacturing steps of the shell and the wind shield are as follows: taking a rectangular sheet as a blank, cutting a plurality of equal-width gaps on one side of the rectangular blank at equal intervals to form a plurality of racks, then bending the racks to form a wind shield, and then bending the rectangular blank along the welding seam to make the two parallel sides of the rectangular blank overlap and be welded to form a closed space region, and the racks are located outside the space region.

[0025] The manufacturing steps of the bottom cover and the vent pipe are as follows: cutting the outer contour of the bottom cover according to the shape of the end surface of one end of the space region formed after the shell is curled, then opening a connecting hole on the bottom cover, and machining the exhaust holes on the circumferential surface of the vent pipe in a central symmetric manner.

[0026] The welding steps of the shell, the bottom cover, the vent pipe and the top cover are as follows: positioning and welding the bottom cover on the axially open end surface of the shell away from the wind shield, positioning and welding the top cover on the end surface of one end of the vent pipe, and then inserting the vent pipe into the connecting hole of the bottom cover and positioning and welding to fix.

[0027] The laying step of the steel wire mesh is as follows: laying and fixing the steel wire mesh inside the space region formed by the shell, and the steel wire mesh covers the vent pipe.

[0028] The installation step of the tin paper is as follows: pasting tin paper on the two surfaces of the wind shield facing the back of the welding seam and away from the back of the welding seam to form a seal, and pasting tin paper on the spot welding between the shell and the bottom cover and the positioning and welding between the bottom cover and the vent pipe to form a seal.

[0029] The adjusting step of the windproof screen is to tightly adhere the windproof screen to the surface opposite to the weld back surface, observe the gap between the two surfaces, if the gap is too large, then adjust the rack in the position area with too large gap alone, bend or twist the whole rack up, down, left and right, or bend or twist part of the rack up, down, left and right (here, part refers to the length of the rack), so that the rack is adhered to the weld back surface.

[0030] Further, in the welding step of the shell, the bottom cover, the vent pipe and the top cover, argon arc spot welding is used for positioning welding, and the welding spots are uniformly distributed, wherein no welding wire is added in the argon arc spot welding of the shell and the bottom cover, and welding wire is added in the argon arc spot welding of the vent pipe and the bottom cover and the top cover.

[0031] Further, in the manufacturing step of the shell and the windproof screen, the space area formed by the shell covers the weld back surface and the weld heat affected zone.

[0032] Compared with the prior art, the present application has the following advantages:

[0033] (1) The windproof screen uses a flexible deformable rack as the framework and tin paper as the sealing layer, the deformation of the rack drives the deformation of the tin paper, so that the windproof screen is significantly different from general flexible windproof structures, and is an adjustable structure between flexibility and rigidity. Since one end of the rack is fixed and the other end is a free end (without constraint), and there is no constraint between adjacent racks, the windproof screen can actively and freely deform or passively and freely deform, active and free deformation means that the windproof screen can be manually adhered to the weld back surface by the operator before each welding to adjust the rack to adapt to the shape characteristics of the part, and passive and free deformation means that the rack can passively adapt to the shape deformation characteristics of the part during the welding process to maintain the relative positional relationship between the two, the two free deformations enable the tool to form a gap with a similar cross section when the protective gas is introduced, so that a stable protective gas pressure is formed, avoiding the situation that the protective gas pressure is unstable due to the inconsistent gap size, and external air is introduced to cause local oxidation.

[0034] (2) The wind shield is composed of multiple independent racks, which can adapt to local deformation and overall deformation during the welding process of the part, and adjacent racks almost do not affect each other. When welding deformation occurs locally, only the corresponding rack and the tin paper will deform to adjust the gap between the wind shield and the back of the weld. Considering that the shape of the rack and the tin paper is adjusted according to the initial shape of the part and closely attached to the back of the weld at the beginning of welding, the shape of the wind shield can almost change synchronously according to the welding deformation. For welding that cannot be completed at one time, the rack can be manually adjusted and the tin paper can be driven to make a relatively large adjustment (adapt to the larger post-weld deformation characteristics of the part) every time the previous welding is completed and the next welding is continued, and a relatively small adjustment is realized by the deformation of the rack and the tin paper itself (the combined action of the pressure of the protective gas flow and the deformation of the welded part) during the welding process.

[0035] (3) The deformation adjustment sensitivity of the wind shield can be adjusted by the length, width, thickness, material properties of the rack and the interval distance of adjacent racks, which is very convenient, has a wide range of applications and is easy to operate. For example, when the thickness of the rack is very thin, the tin paper sealing layer can have very sensitive deformation characteristics. When the thickness of the rack is larger, it can adapt to the situation where the deformation during welding is not large. For example, for the case where the welding deformation area is obviously uneven, multiple racks with different widths can be used. The narrower rack is used for the position with larger deformation amplitude, and the wider rack is used for the position with smaller deformation amplitude, thereby solving the protection problem of different areas when welding irregular deformation.

[0036] (4) The wind shield does not cause the tin paper to contact the weld pool during the welding process due to the rigid support of the rack, and does not introduce excess material. The position of the wind shield is away from the weld pool, which avoids the probability of introducing impurities caused by direct contact.

[0037] (5) The manufacturing process of the wind shield is simple, can be adjusted according to the shape characteristics of the welded part, and the material used has no special requirements, which can be manufactured on site in most processing enterprises. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a schematic diagram of the appearance of the welded joint;

[0039] Figure 2 is a schematic diagram of the assembly method of the back protection tool at the welded joint;

[0040] Figure 3 is a schematic diagram of the appearance of the shell blank;

[0041] Figure 4 is a schematic diagram of the appearance of the bottom cover;

[0042] Figure 5 is a schematic diagram of the forming of the shell and the wind shield;

[0043] Figure 6 is the schematic diagram of the post-welded shape of the shell and the bottom cover;

[0044] Figure 7 is the schematic diagram of the post-welded shape of the vent pipe and the top cover;

[0045] Figure 8 is the schematic diagram of the position of the tin foil on the tooling;

[0046] In the figure: 1 - first piece to be welded, 2 - weld, 3 - second piece to be welded, 4 - argon gas pressure, 5 - air pressure, 6 - shell, 7 - bottom cover, 8 - vent pipe, 9 - inlet argon, 10 - wind shield, 11 - steel wire mesh, 12 - top cover, 13 - tin paper. DETAILED DESCRIPTION

[0047] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments, but should not be understood as limiting the scope of the subject matter described herein to the following embodiments, and any modifications, substitutions and changes made according to ordinary technical knowledge and conventional means in the art without departing from the above technical idea of the present application are included within the scope of the present application.

[0048] As shown in Figure 1 , the joint parts to be welded in the present embodiment include a first piece to be welded 1 as a thin plate panel, a second piece to be welded 3 as a joint nozzle, and a circular weld 2 between them. As shown in Figure 2 , the first piece to be welded 1 around the weld 2 is deformed in a wave shape due to welding.

[0049] As shown in Figures 2 to 8 , the argon arc welding weld back flexible protection tooling designed in the present application specifically includes a shell 6, a bottom cover 7, a vent pipe 8, a rack, a tin paper 13 and a steel wire mesh 11. The shell 6 extends along the weld direction to form a continuous, circumferentially closed, axially open space region, and the weld back is completely located in the space region; the bottom cover 7 connects and blocks the first axially open end surface of the shell 6; the vent pipe 8 passes through the bottom cover 7, and one end of the vent pipe 8 is located in the space region formed by the shell 6, and the other end is in communication with the protective gas source; a plurality of said racks are distributed along the circumference of the shell 6 and form a flexible framework of the wind shield 10 on the outside of the shell 6, one end of the rack is connected at the second axially open end surface of the shell 6, and the other end extends away from the shell 6; the tin paper 13 covers the two surfaces of the rack facing the weld back and facing away from the weld back. Two layers of steel wire mesh 11 are arranged in the space region formed by the shell 6, and the steel wire mesh 11 covers the one end of the vent pipe 8 located in the shell 6, and the mesh holes of the steel wire mesh 11 are axially non-parallel.

[0050] A method for manufacturing a flexible protective fixture for the back side of an argon arc weld includes the following steps:

[0051] Step 1: Press Figure 1 The shape of the weld back protection fixture is set according to the size of the weld joint. The fixture mainly consists of a shell 6, a bottom cover 7, a vent pipe 8, and a top cover 12, with a total height of about 30mm.

[0052] Step 2: Cut the outer shapes of the shell 6, bottom cover 7, vent pipe 8, and top cover 12. The shell 6 is cut according to... Figure 3 Multiple toothed strips are cut out. The protective area of ​​the shell 6 covers the heat-affected zone of the weld by 30mm. The windproof screen 10 designed on the shell 6 is 15mm wide (i.e., the length of the toothed strips). The spacing between any two adjacent toothed strips is 0.5mm, and the width of the toothed strips is 3mm. For example... Figure 4 The bottom cover 7 has two Φ8mm connecting holes, spaced 900mm apart. 2 ~1600 mm 2 The area is increased by one. The vent pipe 8 is 40mm long, has an outer diameter of Φ8mm, and a wall thickness of 0.5mm. Eight symmetrically distributed small holes of Φ0.5mm are provided on the vent pipe 8.

[0053] Step 3: Press Figure 5 , Figure 6 The shell 6 is bent and closed to form a shape (the specific bending shape is as follows). Figure 1 Taking the direction of weld 2 as a reference (in this embodiment, weld 2 is circular, so the shell 6 is bent into a cylindrical shape), and according to... Figure 6 , Figure 7 The shell 6, bottom cover 7, vent pipe 8, and top cover 12 are tack welded together using argon arc welding. No welding wire is added during the argon arc welding of the shell 6 and bottom cover 7; a locating tack weld is performed every 15 mm. Welding wire is added during the locating welds of the vent pipe 8 to the bottom cover 7 and top cover 12; the number of welds is 3, and they are symmetrically distributed.

[0054] Step 4: Press Figure 8 The seams between the spot-welded parts of the housing 6, bottom cover 7, and vent pipe 8 are sealed with aluminum foil 13. The windproof screen 10 area on the housing 6 is also sealed with aluminum foil 13 on both sides of the rack.

[0055] Step 5: Press Figure 2 Two layers of wire mesh 11 are laid on the bottom inner side of the shell 6, and the wire mesh 11 is fixed with tin foil 13 or small steel sheets. The mesh openings of the wire mesh 11 are not parallel in axis, so that different mesh openings can point to different positions on the back of the weld, such as... Figure 2 The image shows multiple upward arrows pointing to different directions.

[0056] Step 6: Press Figure 2Place the flexible protective tool on the back of the welding part, and visually check whether there is a large gap between the wind shield 10 of the tool and the welding part 1, and if there is a large gap, manually adjust the rack corresponding to the position of the gap.

[0057] During use of the protective tool, press the windproof strip 10 of the tool against the welding part 1, and then press the windproof strip 10 of the tool against the welding part 1. Figure 2 Fill argon into the breather pipe 8, and the argon is dispersed for the first time through the exhaust hole of the breather pipe 8 (in the left-right direction), and then dispersed for the second time through the two layers of steel wire meshes 11, so that the argon is in a uniform dispersed state, forms laminar argon to exclude air, and flows to the position of the wind shield 10 to form a stable argon gas pressure 4, which can completely prevent the invasion of the external environmental air pressure 5. Figure 2

[0058] The flexible protective tool of the present application is made of steel, has good rigidity, is durable, and has a windproof strip in structure, and has a flexible clamping protection function for the back of the weld of a thin-walled and easily deformed welding part. The flexible protective tool of the present application is placed on the back of the weld of a part, and protects the back of the weld from oxidation. For a pressure vessel, the protection requirement for the back of the weld is very high, and if oxidation occurs, fuel and lubricating oil will be contaminated during use, thereby affecting the engine.

[0059] The above only describes a specific embodiment of the present application, but the protection scope of the present application is not limited to this, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.​

Claims

1. A method for manufacturing a flexible protection tool for the back of an argon arc welding seam, characterized in that: the flexible protection tool for the back of an argon arc welding seam comprises, a shell (6) extending along the welding seam to form a continuous, circumferentially closed, axially open space region, and the back of the welding seam is completely located in the space region; a bottom cover (7) connected to and sealing the first axially open end surface of the shell (6); a vent pipe (8) penetrating the bottom cover (7), one end of the vent pipe (8) being located in the space region formed by the shell (6), and the other end being in communication with a source of protective gas; a plurality of racks distributed along the circumference of the shell (6) and extending outward from the shell (6) to form a flexible framework of a wind shield (10), one end of the rack being connected to the second axially open end surface of the shell (6), and the other end extending away from the shell (6); tin paper (13) covering both surfaces of the rack facing the back of the welding seam and the back of the welding seam; and a steel mesh (11) arranged in the space region formed by the shell (6), and the steel mesh (11) covering one end of the vent pipe (8) located in the shell (6), the mesh holes of the steel mesh (11) being axially non-parallel; the manufacturing method comprises, a manufacturing step of the shell (6) and the wind shield (10), using a rectangular sheet as a blank, cutting a plurality of equal-width gaps on one side of the rectangular blank to form a plurality of racks, then bending the racks by 90 degrees to form the wind shield (10), and then bending the rectangular blank along the welding seam to make the two parallel sides of the rectangular blank overlap and be welded to form a closed space region, and the racks are located outside the space region; a manufacturing step of the bottom cover (7) and the vent pipe (8), cutting the outer contour of the bottom cover (7) according to the shape of the end surface of the space region formed after the shell (6) is curled, then opening a connecting hole in the bottom cover (7), and machining exhaust holes on the circumferential surface of the vent pipe (8) in a center-symmetrical manner; a welding step of the shell (6), the bottom cover (7), the vent pipe (8), and the top cover (12), positioning and welding the bottom cover (7) to the axially open end surface of the shell (6) away from the wind shield (10), positioning and welding the top cover (12) to the end surface of the vent pipe (8), and then inserting the vent pipe (8) into the connecting hole of the bottom cover (7) and positioning and welding to fix; a laying step of the steel mesh (11), laying the steel mesh (11) inside the space region formed by the shell (6) and fixing it, and the steel mesh (11) covers the vent pipe (8); and a mounting step of the tin paper (13), pasting the tin paper (13) on the two surfaces of the wind shield (10) facing the back of the welding seam and the back of the welding seam to form a seal, and pasting the tin paper (13) on the spot welding between the shell (6) and the bottom cover (7) and the positioning and welding between the bottom cover (7) and the vent pipe (8) to form a seal. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The adjusting step of the wind shield (10) is to tightly adhere the surface of the wind shield (10) opposite to the weld back to the weld back, observe the gap between the two surfaces, if the gap is too large, adjust the rack in the position area with too large gap alone, bend or twist the whole rack up, down, left and right, or bend or twist part of the rack up, down, left and right, so that the rack adheres to the weld back.

2. The method of claim 1, wherein: In the welding step of the shell (6), the bottom cover (7), the vent pipe (8) and the top cover (12), argon arc spot welding is used for positioning welding, and the welding spots are uniformly distributed, wherein no welding wire is added in the argon arc spot welding of the shell (6) and the bottom cover (7), and welding wire is added in the argon arc spot welding of the vent pipe (8), the bottom cover (7) and the top cover (12).

3. The method of claim 1, wherein the flexible backing is formed by: In the manufacturing step of the shell (6) and the wind shield (10), the space area formed by the shell (6) covers the weld back and the weld heat affected zone.

4. The method of claim 1, wherein: The connection between the bottom cover (7) and the axially open end face of the shell (6) is covered with tin paper (13).

5. The method of claim 1, wherein: The vent pipe (8) is provided with exhaust holes at one end of the shell (6), and a plurality of exhaust holes are uniformly distributed on the circumferential surface of the vent pipe (8).

6. The method of claim 1, wherein: The junction between the vent pipe (8) and the bottom cover (7) is covered with tin paper (13).

7. The method of claim 1, wherein: The vent pipe (8) is provided with a top cover (12) at one end of the shell (6).

8. The method of claim 1, wherein: The rack is rectangular, the sizes of adjacent racks are the same, and the intervals between adjacent racks are equal.

Images