Electron beam welding method for space intersecting structure of nozzle and hyperbolic shell

Abstract

The present invention discloses an electron beam welding method for a spatial intersecting structure of a pipe and a hyperbolic shell, which belongs to the field of welding of metal material structural parts, and specifically includes the following steps: S1: opening a hole in the hyperbolic shell; S2: pipe processing: the pipe can be prepared by forging processing or sheet rolling welding according to the thickness of the pipe wall; a process boss is set in the intersecting area of ​​the pipe and the hyperbolic shell; S3: intersecting structure assembly: assembling the pipe and the hyperbolic shell; S4: welding: performing zone welding according to the circumferential thickness curve of the intersecting weld to be welded. The present invention uses an electron beam welding method to design the welding area form of the pipe and the hyperbolic shell in a targeted manner and develop a welding process, and uses a vacuum electron beam welding process for welding of unequal thickness space welds in the intersecting area of ​​the pipe and the hyperbolic shell, which greatly improves the welding efficiency, is not prone to internal welding defects, and realizes high-quality, efficient and low-cost welding of the pipe and head plug-in welds on the end cover of a large-size titanium alloy heat exchanger.

Description

Technical Field

[0001] The invention belongs to the field of welding of metal material structural parts, and in particular relates to an electron beam welding method for a spatial intersecting structure of a nozzle and a hyperbolic shell. Background Art

[0002] Titanium alloy heat exchangers are increasingly widely used in many fields such as petroleum, chemical industry, refrigeration, and shipbuilding due to their outstanding advantages such as low density, high specific strength, non-magnetic, corrosion resistance to various media, and good weldability. With the large-scale and high-parameterization of modern process equipment, titanium alloy heat exchangers also tend to be large-scale and develop in the direction of high temperature and high pressure. For titanium alloy heat exchangers, the tube side is generally the high-pressure side, and the end cover is the pressure boundary of the high-pressure side, which bears high-pressure fatigue, impact, scouring, corrosion, vibration and other loads, and the service environment is relatively harsh.

[0003] In order to ensure better pressure bearing and sealing effects, the thickness of parts is usually large. For large-sized titanium alloy heat exchangers, the thickness of the head and the pipe can reach more than 60 mm. Especially when the pipe on the end cover is non-radially arranged, the actual welding depth of the outer area of ​​the intersecting plug-in weld between the pipe and the head can even reach more than 1.5 times the thickness of the head, which results in a very large amount of welding between the pipe and the head on the end cover.

[0004] This kind of spatially intersecting uneven thickness plug-in structure is difficult to weld using conventional automated welding processes. The existing technology usually uses manual welding with groove opening. This kind of spatial variable thickness intersecting groove weld welding is difficult to process with grooves, requires a large amount of welding fill, consumes a lot of welding materials, and requires very high technical skills of welding workers. In addition, when a large amount of welding fill is used and multi-layer and multi-pass welding is used, the welding efficiency is very low, the welding stress and deformation are large, and defects such as unfused side walls, pores, and cracks are prone to occur. If the defect is located in the middle area of ​​the weld, welding repair is also difficult to implement. Summary of the invention

[0005] In view of this, the conventional welding process for the intersecting through-weld plug-in welds between the pipe and the head on the end cover of a large-sized titanium alloy heat exchanger has the problems of great difficulty in groove processing, large welding filling volume, high requirements on the technical skills of the welding workers, low welding efficiency, serious welding stress and deformation, and easy occurrence of welding defects. The present invention uses an electron beam welding method for the spatial intersecting structure of the pipe and the hyperbolic shell to target the design of the welding area of ​​the pipe and the hyperbolic shell and develop the welding process, and uses the vacuum electron beam welding process for the welding of unequal thickness space welds in the intersecting area between the pipe and the hyperbolic shell, which greatly improves the welding efficiency.

[0006] An electron beam welding method for a space intersecting structure of a nozzle and a hyperbolic shell comprises the following steps:

[0007] S1: Hyperbolic shell opening: opening a pipe hole on the hyperbolic shell by machining;

[0008] S2: Pipe processing: Pipes can be prepared by forging or plate welding according to the pipe wall thickness; a process boss is set in the intersection area between the pipe and the hyperbolic shell;

[0009] S3: Intersecting structure assembly: assembling nozzles and hyperbolic shells;

[0010] S4: Welding: The intersecting welds between the tube and the hyperbolic shell are welded from the inside of the hyperbolic shell by using a vacuum electron beam welding process. The intersecting welds to be welded are divided into zones according to the circumferential thickness curve. The electron beam flow curve and the electron beam focal length curve in each zone change according to a linear function.

[0011] Furthermore, the relationship between the opening radius of the pipe hole and the radius of the corresponding pipe is as follows: R 接管孔 =R 接管 +T, where T is the thickness of the process boss added in the intersecting area between the connecting pipe and the hyperbolic shell.

[0012] Furthermore, the process boss is specifically a circular ring-shaped boss surrounding the connecting area between the connecting pipe and the hyperbolic shell.

[0013] Furthermore, the thickness T of the process boss is 2-4 mm, and the height H of the process boss is related to the fitting position of the connecting pipe and the insertion area of ​​the hyperbolic shell.

[0014] Furthermore, the assembly matching dimensions of the connecting pipe and the hyperbolic shell are ensured by machining, wherein the assembly clearance between the connecting pipe and the hyperbolic shell is ≯0.1 mm, and the misalignment is ≯0.5 mm.

[0015] Furthermore, a special space annular bottom locking tool is installed at the position where the connecting pipe is close to the outer wall of the hyperbolic shell, wherein the thickness of the space annular bottom locking tool is 30-60 mm, the width is 20-50 mm, and its material is the same as that of the hyperbolic shell.

[0016] Furthermore, the fitting surface between the spatial annular lock bottom tooling and the hyperbolic shell is processed by matching processing, and the fitting clearance between the spatial annular lock bottom tooling and the connecting pipe after processing is ≯0.5mm, and the fitting clearance between the spatial annular lock bottom tooling and the outer surface of the hyperbolic shell is ≯1mm.

[0017] Furthermore, the intersection area of ​​the hyperbolic shell and the nozzle is divided into 8 partitions, with each partition being 45°.

[0018] Furthermore, two adjacent connecting pipes are arranged on the hyperbolic shell, and the 0° starting point of the circumferential welding is the position where the thickness of the circumferential weld between the two connecting pipes and the hyperbolic shell is the thinnest.

[0019] Furthermore, the circumferential welding 0° is the welding starting point, and the welding direction is the direction from thin to thick of the circumferential weld.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1) The present invention adopts targeted design and welding process development for the welding area of ​​the tube and the hyperbolic shell, and uses the vacuum electron beam welding process for welding of unequal thickness space welds in the intersecting area of ​​the tube and the hyperbolic shell, which greatly improves the welding efficiency, makes internal welding defects less likely to occur, and the welding stress and deformation are much lower than those of conventional manufacturing processes.

[0022] 2) The present invention uses electron beam welding to weld the intersecting joint of the pipe and the hyperbolic shell instead of manual welding by beveling in the prior art, thereby saving processing costs, labor costs and welding material costs, and achieving high-quality, efficient and low-cost welding of the joint weld between the pipe and the head on the end cover of a large-sized titanium alloy heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the intersecting structure of the connecting pipe and the hyperbolic shell of the present invention;

[0024] Figure 2 It is a front view of the structure of the connecting pipe and the hyperbolic shell intersecting the present invention;

[0025] Figure 3 For the present invention Figure 2 A partial enlarged view of the A part;

[0026] Figure 4 For the present invention Figure 2 A partial enlarged view of the B area;

[0027] Figure 5 For the present invention Figure 2 A partial enlarged view of the middle C area;

[0028] Figure 6 This is a schematic diagram of the pipe welding of the present invention;

[0029] Figure 7 For the present invention Figure 6 A partial enlarged view of the D part;

[0030] Figure 8 This is a schematic diagram of electron beam welding of the present invention;

[0031] Fig. 9 It is a schematic diagram of the circumferential partitioning and related parameter changes of the structure of the connecting pipe and the hyperbolic shell of the present invention.

[0032] Reference numerals:

[0033] Hyperbolic shell 1, spatial annular bottom locking tooling 12; pipe hole 2, pipe 3, first pipe 31, second pipe 32; first partition 41, second partition 42, third partition 43, fourth partition 44, fifth partition 45, sixth partition 46, seventh partition 47, eighth partition 48. DETAILED DESCRIPTION

[0034] A method for electron beam welding of a nozzle and a hyperbolic shell intersecting structure comprises the following steps:

[0035] S1: Opening a hole in the hyperbolic shell 1: opening a pipe hole 2 on the hyperbolic shell 1 by machining;

[0036] Specifically, the opening center of the pipe hole 2 and the center of the pipe 3 are at the same theoretical installation position, and the opening radius of the pipe hole 2 and the corresponding radius of the pipe 3 are in the following relationship: R 接管孔 =R 接管 +T, where T is the thickness of the process boss added in the plug-in intersection area between the pipe 3 and the hyperbolic shell 1;

[0037] S2: Processing of the pipe 3: The pipe 3 can be processed by forging or by plate welding according to the wall thickness of the pipe 3; a process boss is set in the intersecting area of ​​the pipe 3 and the hyperbolic shell 1;

[0038] See attached for details Figures 2 to 5 The process boss is specifically a circular boss surrounding the plug-in area of ​​the connecting pipe 3 and the hyperbolic shell 1, wherein the thickness T of the process boss is 2-4 mm, and the height H of the process boss is related to the fitting position of the connecting pipe 3 and the hyperbolic shell 1 in the plug-in area.

[0039] Regardless of the process used to prepare the connecting pipe 3, it is necessary to consider leaving a processing allowance for the process boss in the plug-in area between the connecting pipe 3 and the hyperbolic shell 1, and the process boss should be added when cutting and processing the raw material of the connecting pipe 3.

[0040] S3: Intersecting structure assembly: assembling the nozzle 3 and the hyperbolic shell 1;

[0041] The assembly matching dimensions of the connecting pipe 3 and the hyperbolic shell 1 are ensured by machining, wherein the assembly clearance is ≯0.1 mm and the misalignment is ≯0.5 mm.

[0042] As attached Figure 6 As shown, during the assembly process, the connecting pipe 3 and the hyperbolic shell 1 are placed inverted, the electron beam is injected vertically, and a special space ring locking bottom tooling 12 is assembled at the position where the connecting pipe 3 is close to the outer wall of the hyperbolic shell 1, wherein the thickness S of the space ring locking bottom tooling 12 is 30~60mm, the width W is 20~50mm, and its material is the same as that of the hyperbolic shell 1.

[0043] The fitting surface between the spatial annular bottom lock tooling 12 and the hyperbolic shell 1 is processed by matching processing. After processing, the fitting gap between the spatial annular bottom lock tooling 12 and the pipe 3 is a≯0.5mm, and the fitting gap between the spatial annular bottom lock tooling 12 and the outer surface of the hyperbolic shell 1 is b≯1mm.

[0044] After the pipe 3 and the hyperbolic shell 1 are assembled, the spatial annular bottom lock fixture 12 and the hyperbolic shell 1 are fixed by manual TIG spot welding.

[0045] S4: Welding: The intersecting welds between the tube 3 and the hyperbolic shell 1 are welded from the inside of the hyperbolic shell 1 by using a vacuum electron beam welding process. The intersecting welds to be welded are divided into zones according to the circumferential thickness curve. The electron beam current and the electron beam focal length in each zone vary according to a linear function.

[0046] During the welding process, the electron beam welding process performs reasonable zoning according to the circumferential thickness of the intersecting welds to be welded. For areas with different circumferential thicknesses, the required electron beam current and electron beam focal length are different: for thick areas, the electron beam current and electron beam focal length are increased to ensure weld penetration; for thin areas, the electron beam current and electron beam focal length need to be adaptively reduced to ensure welding quality.

[0047] In actual situations, the desired welding effect can be obtained by specifically refining the partitions and the electron beam current variation function according to the circumferential thickness variation of the weld to be welded, such as Figures 8-9 As shown, the intersection area of ​​the hyperbolic shell 1 and the tube 3 is divided into 8 partitions, each 45° is a partition, and the electron beam current and the electron beam focal length in each partition change with the partition according to a linear function law, wherein the circumferential welding 0° starting point of the two tubes 3 is the position where the circumferential weld thickness of the two tubes and the hyperbolic shell is the thinnest; specific welding direction: the circumferential welding 0° is the welding starting point, and the welding direction is the direction from thin to thick circumferential weld thickness.

[0048] According to the actual circumferential thickness of the intersecting welds to be welded, reasonable partitioning is performed, and fully automatic welding is achieved through the welding positioner; the size of the electron beam current is set to ensure that the thickness to be welded is fully penetrated, and the root of the electron beam melting zone is located inside the space annular bottom lock tooling 12. The welding sequence is as follows: Figure 8 As shown, the circumference is divided into 8 partitions from the joint between the connecting tube 3 and the hyperbolic shell 1, and welding is started from 0° of the first partition 41, and electron beam welding is performed in the order of the first partition 41 to the eighth partition 48. From 0 to 180°, the electron beam current and the electron beam focus are synchronously adaptively increased according to the actual change of welding thickness. At 180°, the welding thickness, electron beam current and electron beam focal length all reach the maximum value; from 180 to 360°, the electron beam current and the electron beam focus also need to be synchronously adaptively reduced according to the change of actual welding thickness.

[0049] After the electron beam welding is completed, the space annular bottom lock tooling 12 is removed, and the front and back sides of the weld are mechanically polished to clean the spatter and the poorly formed area near the surface, and then the conventional manual TIG welding process is used to perform the decoration and beautification welding of the inner and outer surfaces of the weld and to make necessary fillet welds.

[0050] Example 1

[0051] The present invention's tube and hyperbolic shell intersecting structure and its electron beam welding method have been put into practical mass production in the processing and manufacturing of a large titanium alloy heat exchanger end cover. The process method is stable and feasible, greatly improving the welding efficiency, not prone to internal welding defects, and the welding stress and deformation are much lower than the conventional manufacturing process. The manufacturing cycle can be reduced by more than 80% compared with the traditional process route, saving processing fees, labor costs and welding material costs. The welding process is changed from manual to mobile, reducing labor intensity and improving the level of automation. High-quality, efficient and low-cost welding of the tube and head plug-in weld on the end cover of a large-scale titanium alloy heat exchanger is achieved, which has significant economic and social benefits and promotion and application value.

[0052] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. An electron beam welding method for a space intersecting structure between a nozzle and a hyperbolic shell, characterized in that: The following steps are involved: S1: opening a hole in the hyperbolic shell (1): opening a pipe connection hole (2) in the hyperbolic shell (1) by machining; S2: Processing of the connecting pipe (3): The connecting pipe (3) can be prepared by forging or sheet metal rolling according to the wall thickness of the connecting pipe (3); a process boss is provided in the intersecting region between the connecting pipe (3) and the hyperbolic shell (1); the process boss is specifically a circular boss surrounding the plug-in region between the connecting pipe (3) and the hyperbolic shell (1); the thickness T of the process boss is 2 to 4 mm; the height H of the process boss is related to the fitting position of the plug-in region between the connecting pipe (3) and the hyperbolic shell (1); S3: Intersecting structure assembly: Assembling the connecting pipe (3) and the hyperbolic shell (1); during the assembly process, the connecting pipe (3) and the hyperbolic shell (1) are placed upside down, and the electron beam is injected vertically, and a special space ring-shaped bottom locking tool (12) is assembled at a position where the connecting pipe (3) is close to the outer wall of the hyperbolic shell (1), wherein the thickness of the space ring-shaped bottom locking tool (12) is 30 to 60 mm, the width is 20 to 50 mm, and the material thereof is the same as that of the hyperbolic shell (1). The fitting surfaces of the spatial annular bottom locking tooling (12) and the hyperbolic shell (1) are processed by matching processing, and the fitting clearance between the spatial annular bottom locking tooling (12) and the pipe (3) after processing is ≯0.5mm, and the fitting clearance between the spatial annular bottom locking tooling (12) and the outer surface of the hyperbolic shell (1) is ≯1mm; S4: Welding: A vacuum electron beam welding process is used to weld the intersecting weld between the pipe (3) and the hyperbolic shell (1) from the inside of the hyperbolic shell (1). The weld is divided into 8 zones according to the circumferential thickness curve of the intersecting weld to be welded, with each zone being 45°. The electron beam current curve and the electron beam focal length curve in each zone change according to a linear function. From the range of 0 to 180°, the electron beam current and the electron beam focus increase in synchronization with the actual change in weld thickness. From the range of 180 to 360°, the electron beam current and the electron beam focus decrease in synchronization with the actual change in weld thickness.

2. The electron beam welding method according to claim 1, characterized in that: The relationship between the opening radius of the connecting pipe hole (2) and the radius of the corresponding connecting pipe (3) is as follows: R 接管孔 =R 接管 +T, wherein T is the thickness of the process boss added in the plug-in intersection area between the connecting pipe (3) and the hyperbolic shell (1).

3. The electron beam welding method according to claim 1, characterized in that: The assembly matching dimensions of the connecting pipe (3) and the hyperbolic shell (1) are ensured by machining, wherein the assembly clearance between the connecting pipe (3) and the hyperbolic shell (1) is ≯0.1 mm, and the misalignment is ≯0.5 mm.

4. The electron beam welding method according to claim 1, characterized in that: Two adjacent connecting pipes (3) are arranged on the hyperbolic shell (1), and the 0° circumferential welding starting point is the position where the circumferential weld thickness of the two connecting pipes (3) and the hyperbolic shell (1) is the thinnest.

5. The electron beam welding method according to claim 4, characterized in that: The circumferential welding 0° is the welding starting point, and the welding direction is the direction from thin to thick of the circumferential weld.

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