Composite welding method for austenitic stainless steel plate

Abstract

The present invention relates to the field of welding processing technology for steel, and discloses a composite welding method for austenitic stainless steel plates. The method comprises the following steps: Step 1: Prepare two plate materials, and U-shaped grooves and I-shaped grooves are formed at the ends of each plate material; Step 2: Assemble the groove ends of the two plate materials to form an assembly, and the I-shaped grooves of the two plate materials are arranged in a fitting manner; Step 3: Place the assembly in a working chamber, heat the assembly to a preset temperature, and evacuate the working chamber to a preset vacuum degree; Step 4: Weld the assembly by electron beam welding; Step 5: Machine the reinforcement of the electron beam weld seam to smoothly transition the transition position between the U-shaped groove and the I-shaped groove; Step 6: Perform filler wire welding at the U-shaped groove of the assembly. Thus, by combining the welding methods of electron beam welding and filler wire welding to weld the two plate materials, the welding requirements for large thickness (such as plate materials with a thickness of more than 160 mm) can be met, and the welding efficiency and the weld quality can be improved.

Description

Technical Field

[0001] The present application relates to the field of steel welding processing technology, and in particular to a composite welding method for austenitic stainless steel plates. Background Art

[0002] At present, austenitic stainless steel is widely used in petroleum, chemical industry, nuclear power, fusion reactor and other fields due to its excellent corrosion resistance and high strength. A large number of equipment use thick austenitic stainless steel plates as supporting structures, and the plate thickness is generally greater than 80mm. To achieve the welding of such thick austenitic stainless steel plates, it is necessary to overcome the difficulties of large welding deformation, easy cracking, complex process and low operating efficiency.

[0003] In the related art, thick stainless steel plates are usually welded by manual argon arc welding, metal electrode gas shielded welding, laser wire welding, laser welding and vacuum electron beam welding.

[0004] Among them, the greater the thickness of the stainless steel plate, the greater the difficulty of welding. In some schemes, in order to improve the quality of the weld, austenitic stainless steel is welded by laser welding combined with laser wire welding. However, laser welding requires double-sided welding when welding thick stainless steel plates with higher plate thickness, so quality defects are prone to occur at the double-sided weld positions and are difficult to remedy. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present application is to propose a composite welding method for austenitic stainless steel plates, which can improve welding efficiency and weld quality and achieve efficient welding of austenitic stainless steel plates.

[0006] The composite welding method of austenitic stainless steel plates according to the embodiment of the present application includes the following steps: step 1: preparing two sheets, and the end of each sheet is processed to form a U-shaped groove and an I-shaped groove; step 2: assembling the groove ends of the two sheets to form an assembly, and the I-shaped grooves of the two sheets are arranged in a fitting manner; step 3: placing the assembly in a working room, and heating the assembly to a preset temperature, and evacuating the working room to a preset vacuum degree; step 4: welding the assembly by electron beam welding; step 5: processing the electron beam welding weld excess height formed by electron beam welding, and smoothly transitioning the transition position of the U-shaped groove and the I-shaped groove; step 6: performing filler wire welding on the U-shaped groove of the assembly.

[0007] According to some embodiments of the present application, step two also includes: fixing a gasket on a side of the assembly away from the U-shaped groove, and respectively assembling an arc starting plate and an arc ending plate at both ends of the I-shaped groove.

[0008] According to some embodiments of the present application, the composite welding method of the austenitic stainless steel plate further includes Step Seven: disassembling the gasket fixed to the assembly and cleaning the surface of the laser wire filling weld seam of the wire filling weld.

[0009] According to some embodiments of the present application, in Step Three, the preset temperature is above 100°C, and the preset vacuum degree is lower than 5×10 -2 Pa.

[0010] According to some embodiments of the present application, in Step Four, welding the assembly by electron beam welding includes: performing electron beam positioning welding on the I-shaped groove of the assembly with first preset parameters, and the focal position is the surface focus; welding the assembly along the weld seam of the electron beam positioning welding with second preset parameters, and the focal position is the lower focus.

[0011] According to some embodiments of the present application, the first preset parameters include: using a beam current intensity of 5 mA - 15 mA, a surface moving speed of 3 mm / s, a voltage of 150 kV, and a working distance of 600 mm - 1000 mm; the second preset parameters include: using a beam current intensity of 180 mA - 230 mA, a surface moving speed of 3 mm / s, a voltage of 150 kV, and a working distance of 600 mm - 1000 mm.

[0012] According to some embodiments of the present application, after welding the assembly by electron beam welding in Step Four, it further includes: cooling the assembly in the working chamber for a preset time.

[0013] According to some embodiments of the present application, the preset time is not less than 12 h.

[0014] According to some embodiments of the present application, the wire filling welding process in Step Six is one of the laser wire filling welding process and the submerged arc welding process.

[0015] According to some embodiments of the present application, the thickness of the sheet material is L, and it satisfies the relationship: L≥80 mm; and / or, the thickness of each sheet material at the U-shaped groove is L1, and it satisfies the relationship: L1≥30 mm; and / or, the thickness of each sheet material at the I-shaped groove is L2, and it satisfies the relationship: L2≥50 mm.

[0016] In summary, the composite welding method of the austenitic stainless steel plate according to the embodiments of the present application has at least the following advantages compared with the prior art:

[0017] (1) The composite welding method combining electron beam welding and laser wire filling welding can achieve the welding of austenitic stainless steel sheet materials with a thickness of more than 160 mm;

[0018] (2) The welding of the sheet metal at the I-shaped groove is achieved by vacuum electron beam welding. Without multi-layer and multi-pass welding, the welding efficiency can be improved. Moreover, vacuum electron beam welding can avoid the influence of multiple heat inputs, improve the quality of the weld joint, and does not require the filling of deposited metal, saving the consumption of welding materials, reducing the welding cost. At the same time, the vacuum electron beam welding has a small linear energy and a fast welding speed, resulting in small welding deformation.

[0019] (3) The welding of the assembly at the U-shaped groove is completed by laser wire filling welding, with small heat input and deformation and excellent weld quality.

[0020] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. Description of the Drawings

[0021] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, where:

[0022] Figure 1 is a schematic assembly diagram of two sheet metals according to an embodiment of the present application;

[0023] Figure 2 is a schematic diagram of the cooperation of the sheet metal with the gasket, starting plate, and ending plate according to an embodiment of the present application;

[0024] Figure 3 is a schematic diagram of the electron beam weld and the laser wire filling weld according to an embodiment of the present application;

[0025] Figure 4 is an electron beam weld diagram according to an embodiment of the present application;

[0026] Figure 5 is the microscopic metallographic inspection result according to an embodiment of the present application;

[0027] Figure 6 is the tensile test result according to an embodiment of the present application;

[0028] Figure 7 is the bending test result according to an embodiment of the present application;

[0029] Figure 8 is the impact test result according to an embodiment of the present application;

[0030] Figure 9 is a flowchart of the composite welding method according to an embodiment of the present application.

[0031] Reference Signs:

[0032] Sheet 1; I-shaped groove 2; U-shaped groove 3; backing 4; starting plate 51; ending plate 52; electron beam welding seam 6; laser filler wire welding seam 7. Specific embodiments

[0033] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0034] Reference is made below Figures 1-9 to describe a composite welding method for austenitic stainless steel plates according to an embodiment of the present application. The above composite welding method can be applied to the welding of austenitic stainless steel plates to improve welding efficiency and weld quality and achieve efficient welding of austenitic stainless steel plates.

[0035] Specifically, the composite welding method at least includes the following steps: Step 1: Prepare two sheets 1, and U-shaped grooves 3 and I-shaped grooves 2 are formed at the ends of each sheet 1; Step 2: Assemble the grooved ends of the two sheets 1 to form an assembly, and the I-shaped grooves 2 of the two sheets 1 are arranged in contact; Step 3: Place the assembly in a working chamber, heat the assembly to a preset temperature, and evacuate the working chamber to a preset vacuum degree; Step 4: Weld the assembly by electron beam welding; Step 5: Machine the reinforcement of the electron beam welding seam 6 formed by electron beam welding to smoothly transition the transition position between the U-shaped groove 3 and the I-shaped groove 2; Step 6: Perform filler wire welding on the U-shaped groove 3 of the assembly.

[0036] Refer to Figure 1 As shown, during the welding process, first prepare two sheets 1. Each sheet 1 is a stainless steel sheet made of austenitic stainless steel, and U-shaped grooves 3 and I-shaped grooves 2 are formed at the welding ends of the two sheets 1. When it is necessary to arrange the two sheets 1 in the welding mating position, the I-shaped grooves 2 of the two sheets 1 are arranged in contact, that is, there is no gap between the I-shaped grooves 2 of the two sheets 1, to improve the mating tightness between the two sheets 1 and form an assembly by mating the two sheets 1.

[0037] Furthermore, place the assembly in a working chamber and heat the assembly through a heating device so that the assembly reaches a preset temperature, and then further adjust the vacuum degree of the working chamber to the preset vacuum degree by evacuation to prepare for the subsequent electron beam welding of the assembly.

[0038] It should be noted that the above "working chamber" refers to the accommodation space for arranging the assembly, and functions such as heating the assembly and adjusting the vacuum degree can be realized in this accommodation space, and at the same time, electron beam welding operations can be performed on the assembly.

[0039] Among them, in the welding process of electron beam welding, the two sheet materials 1 only need to be closely attached at the I-shaped groove 2 to meet the welding requirements, reducing the need for the sheet material 1 to be grooved, and significantly reducing the amount of welding consumables, saving costs and welding time while improving welding efficiency.

[0040] After the assembly is processed by the electron beam welding process, the electron beam weld 6 formed by the electron beam welding can be processed, so that the assembly can smoothly transition in the adjacent transition region between the I-shaped groove 2 and the U-shaped groove 3, facilitating the filler wire welding at the U-shaped groove 3 of the assembly and ensuring the welding effect at the U-shaped groove 3 of the assembly.

[0041] It can be understood that the processing method for the reinforcement height of the electron beam weld 6 formed by the electron beam welding can be machining, specifically, it can be processed by machining processes such as milling the edge, and the processing method is not limited here, as long as the reinforcement height of the electron beam weld 6 can be processed and the adjacent region between the U-shaped groove 3 and the I-shaped groove 2 can be smoothly transitioned.

[0042] Thus, in the welding process of austenitic stainless steel plates, the two sheet materials 1 are first welded by the electron beam welding method, and then the assembly composed of the two sheet materials 1 is further welded by the filler wire welding method (such as laser filler wire welding), so that the heat affected zones of the welds (including the electron beam weld 6 and the laser filler wire weld 7) of the two sheet materials 1 are narrow, and the grain structures of the welds and the heat affected zones are fine, and the joint performance is excellent. That is to say, by combining the two welding processes, the processing requirements for the groove during the welding of the sheet material 1 can be reduced, and the welding efficiency can be improved.

[0043] It should be noted that currently, stainless steel thick plates are usually welded by welding methods such as manual argon arc welding, gas metal arc welding, laser filler wire welding, laser welding, and vacuum electron beam welding. In the related art, the greater the thickness of the stainless steel plate, the greater the welding difficulty. In some solutions, laser welding combined with laser filler wire welding is used to weld austenitic stainless steel to improve the weld quality. However, when laser welding is used to weld stainless steel thick plates with a relatively high thickness, double-sided welding is required, resulting in quality defects at the double-sided weld positions and great difficulty in remedying them, and thus unable to meet the welding requirements for stainless steel plates with a relatively large thickness.

[0044] In the present application, during the welding process of the two sheet materials 1 (austenitic stainless steel sheet materials), first, the two sheet materials 1 are welded by the electron beam welding method, and then the filler wire welding is further used to fill the solder at the U-shaped groove 3 of the assembly composed of the two sheet materials 1 and perform welding, so as to meet the welding requirements for the sheet material 1 with a relatively large thickness (such as a thickness greater than 160 mm, etc.).

[0045] Specifically, by performing electron beam welding in a working chamber with a certain degree of vacuum, multi-layer and multi-pass welding is not required, saving welding steps and improving welding efficiency. At the same time, the electron beam welding has a small linear energy, a high welding speed, and small welding deformation, which can ensure the welding quality. Meanwhile, compared with laser welding, the electron beam welding has a higher double-sided welding efficiency and can avoid the influence of multiple heat inputs, thereby improving the quality of the weld joint. At the same time, there is no need to fill the deposited metal between the two plates 1, which can save the amount of welding materials.

[0046] Combined with Figure 1 and Figure 2 As shown, in some embodiments of the present application, step two further includes: fixedly arranging a backing 4 on the side of the assembly away from the U-shaped groove 3, and respectively assembling a starting plate 51 and an ending plate 52 at both ends of the I-shaped groove 2.

[0047] It can be understood that by arranging the backing 4 on the assembly, it can effectively prevent the back of the assembly (i.e., the side of the assembly away from the U-shaped groove 3) from having welding leakage and collapse, improving the reliability and safety of the welding process. At the same time, by respectively arranging the starting plate 51 and the ending plate 52 at both ends of the I-shaped groove 2, the welding quality at the starting and ending positions of the weld can be improved.

[0048] In a further embodiment of the present application, the composite welding method further includes step seven: disassembling the backing 4 fixed to the assembly and cleaning the surface of the laser filler wire weld 7 of the filler wire welding.

[0049] It can be understood that after welding the assembly by filler wire welding, the welding operation of the assembly is completed, that is, there is no need to protect the assembly through the backing 4, and the backing 4 can be disassembled from the assembly to facilitate further cleaning of the laser filler wire weld 7 formed by the filler wire welding.

[0050] In some embodiments of the present application, in the above step three, the preset temperature is above 100 °C, and the preset vacuum degree is lower than 5×10 -2 Pa.

[0051] It should be noted that the preset temperature can be a range parameter, such as: 100 °C - 150 °C. When the preset temperature is within the above parameter range, the vacuum degree of the working chamber can be adjusted so that the vacuum degree of the vacuum chamber is lower than 5×10 - 2 Pa to achieve vacuum electron beam welding of the assembly and improve the welding effect of the assembly at the I-shaped groove 2.

[0052] In some embodiments of the present application, in step four, further including welding the assembly by electron beam welding: performing electron beam tack welding on the V-groove 2 of the assembly with a first preset parameter, and the focus position is the surface focus; welding the assembly along the weld of the electron beam tack welding with a second preset parameter, and the focus position is the lower focus.

[0053] That is to say, during the process of electron beam welding the assembly, there are two welding operations. First, perform electron beam tack welding on the assembly with a first preset parameter, and the focus of the electron beam tack welding is located on the surface of the assembly, so as to position the two sheet metals 1; second, the positioned assembly is further welded by electron beam with a second preset parameter to achieve the welding fit of the two sheet metals 1 at the V-groove 2, and the focus of the electron beam welding is the lower focus, which can ensure the welding depth of the electron beam welding and improve the welding effect of the two sheet metals 1 at the V-groove 2.

[0054] In some embodiments of the present application, the first preset parameter includes: using a beam current intensity of 5 mA - 15 mA, a surface moving speed of 3 mm / s, a voltage of 150 kV, and a working distance of 600 mm - 1000 mm; the second preset parameter includes: using a beam current intensity of 180 mA - 230 mA, a surface moving speed of 3 mm / s, a voltage of 150 kV, and a working distance of 600 mm - 1000 mm.

[0055] Wherein, the above-mentioned "surface moving speed" refers to the moving speed of the welding equipment relative to the assembly; the above-mentioned "working distance" refers to the distance between the output end of the equipment emitting the electron beam and the assembly.

[0056] In some embodiments of the present application, after welding the assembly by electron beam welding in step four, it further includes: cooling the assembly in the working chamber for a preset time to improve the weld microstructure properties.

[0057] It can be understood that the composite welding method in the present application is applicable to the sheet metal 1 with a relatively large thickness. Since the welding thickness dimension of the sheet metal 1 at the V-groove 2 is relatively large, by slowly cooling the assembly in the vacuum environment formed in the working chamber, the grains can be refined, the weld microstructure properties can be improved, and the welding effect of the electron beam welding on the assembly can be enhanced.

[0058] In a further embodiment of the present application, the preset time is not less than 12 h, so as to achieve sufficient cooling of the assembly.

[0059] Wherein, the assembly can be cooled by natural cooling, and the cooling environment of the assembly is the working chamber, so that the assembly after electron beam welding cools slowly in a vacuum state, thereby enhancing the effect of refining grains and improving the weld microstructure properties.

[0060] In some embodiments of the present application, the wire filling welding process in step six is one of the laser wire filling welding process and the submerged arc welding process to meet the welding requirements of the assembly at the U-shaped groove 3.

[0061] Among them, the laser wire filling welding process refers to: adding a welding wire during the laser welding process, so that the welding process has the high energy density and fast welding speed of the laser, and has the metallurgical reaction and molten pool formation of the arc, which helps to improve the weld performance; the submerged arc welding process refers to: melting the welding wire, flux and base metal by arc heating and filling them between the workpieces, and forming a weld after cooling to connect the workpieces together, and has the advantages of high welding efficiency, good welding quality, no arc light and less smoke and dust.

[0062] In a specific embodiment of the present application, taking the laser wire filling welding process as an example. In the laser wire filling welding process, the laser power is 4 kw - 7 kw, the welding speed is 6 mm / s - 11 mm / s, the defocus amount is 40 mm - 70 mm, and N2 (nitrogen) is used as the shielding gas, the nitrogen concentration ≥ 99.99%, the flow rate is 40 L / min - 70 L / min, and an austenitic stainless steel welding wire with a diameter of φ1.6 mm is used for laser wire filling welding, and the wire feeding speed is 140 cm / min - 260 cm / min. It should be noted that the laser wire filling welding process is not limited to the above parameters, and the specific parameters can be adjusted adaptively according to the actual welding requirements.

[0063] In some embodiments of the present application, the thickness of the sheet 1 is L, and satisfies the relationship: L ≥ 80 mm.

[0064] In some embodiments of the present application, the thickness of each sheet 1 at the U-shaped groove 3 is L1, and satisfies the relationship: L1 ≥ 30 mm.

[0065] In some embodiments of the present application, the thickness of each sheet 1 at the I-shaped groove 2 is L2, and satisfies the relationship: L2 ≥ 50 mm.

[0066] Among them, the sheet 1 applying the composite welding method of the embodiments of the present application can simultaneously meet the above multiple groups of parameters. For example: L is 160 mm, L1 is 60 mm, L2 is 100 mm, etc.

[0067] It should be noted that the composite welding method of the austenitic stainless steel plate according to the embodiments of the present application can meet the welding requirements of the sheet 1 with a larger thickness (such as: L ≥ 160 mm) through the welding method combining vacuum electron beam welding and laser wire filling welding.

[0068] In a specific embodiment of applying the above composite welding method: the beam current intensity used in electron beam welding is 180 - 230 mA, the surface moving speed is 3 mm / s, the voltage is 150 kV, the working distance is 600 - 1000 mm, the focus position is the lower focus, and the assembly is slowly cooled in a vacuum state for 12 hours after electron beam welding. The reinforcement of the electron beam weld 6 formed by electron beam welding is machined by mechanical processing to make the transition position between the U-shaped groove 3 and the I-shaped groove 2 smooth, so as to improve the fusion quality of laser wire filling welding and the electron beam weld.

[0069] Therefore, compared with the traditional manual argon arc welding and gas metal arc welding methods, the welding efficiency and weld quality are improved, and the high-efficiency welding of thick stainless steel plates is realized.

[0070] At the same time, combined with Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 the analysis of the welded product effect obtained by the composite welding method of this application. Referring to Figure 4 , in the weld cross-section diagram formed by electron beam welding, the weld is uniform and the fusion effect is good; referring to Figure 5 , in the results of microscopic metallographic inspection, no microcracks are found in the weld; referring to Figure 6 , in the results of the tensile test, the tensile strength at the weld is greater than that of the base metal; referring to Figure 7 , in the results of the bending test, the welded joint has no cracks when bent 180° laterally; referring to Figure 8 , in the results of the impact test, the impact absorption energy is greater than 60 J (joules).

[0071] Therefore, using the composite welding method in the embodiment of this application can make the welding between the sheet materials 1 stable, and the tensile strength of the welded joint (at room temperature, such as: 23 °C) is greater than that of the base metal. The side bending test and impact test of the welded joint both meet the specification requirements.

[0072] In summary, the composite welding method of austenitic stainless steel plates according to the embodiment of this application has at least the following advantages compared with the prior art:

[0073] (1) The composite welding method combining electron beam welding and laser wire filling welding can realize the welding of austenitic stainless steel sheet materials with a thickness of more than 160 mm;

[0074] (2) The welding of sheet materials at the I-shaped groove is realized by vacuum electron beam welding, without multi-layer and multi-pass welding, which can improve the welding efficiency. And vacuum electron beam welding can avoid the influence of multiple heat inputs, improve the quality of the weld joint, and does not require filling of welding metal, saving the consumption of welding materials, reducing the welding cost. At the same time, the vacuum electron beam welding has a small linear energy and a fast welding speed, and the welding deformation is small.

[0075] (3) The assembly is welded at the U-groove by laser wire filling welding, which has small heat input and deformation and excellent weld quality.

[0076] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application 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. Therefore, it should not be construed as a limitation to the present application.

[0077] In the description of the present application, the "first feature" and "second feature" may include one or more of such features.

[0078] In the description of the present application, the meaning of "a plurality" is two or more.

[0079] In the description of the present application, that the first feature is "above" or "below" the second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but in contact through additional features therebetween.

[0080] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0081] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A composite welding method for austenitic stainless steel plates, characterized in that: The following steps are involved: Step 1: preparing two sheets of sheet metal, and processing the ends of each sheet of sheet metal to form a U-shaped groove and an I-shaped groove; Step 2: Assembling the groove ends of the two sheets to form an assembly, and arranging the I-shaped grooves of the two sheets in a close fit; Step 3: placing the assembly in a working chamber, heating the assembly to a preset temperature, and evacuating the working chamber to a preset vacuum degree; Step 4: welding the assembly by electron beam welding, and cooling the assembly by natural cooling in the vacuum environment formed in the studio for a preset time, and the preset time is not less than 12 hours; Step 5: Processing the electron beam welding weld excess height formed by electron beam welding to smoothly transition the transition position between the U-shaped groove and the I-shaped groove; Step 6: Perform wire-filling welding on the U-shaped groove of the assembly; Wherein, the sheet thickness is L, and satisfies the relationship: L≥80mm; And / or, the thickness of each of the plates at the U-shaped groove is L1, and satisfies the relationship: L1 ≥ 30 mm; And / or, the thickness of each of the plates at the I-shaped groove is L2, and satisfies the relationship: L2≥50mm.

2. The composite welding method of austenitic stainless steel plate according to claim 1, characterized in that: The step 2 also includes: A liner is fixedly arranged on one side of the assembly body away from the U-shaped groove, and an arc starting plate and an arc closing plate are respectively arranged on both ends of the I-shaped groove.

3. The composite welding method of austenitic stainless steel plate according to claim 2, characterized in that: Also includes step seven: The gasket fixed to the assembly body is disassembled, and the surface of the filler wire weld of the filler wire weld is cleaned.

4. The composite welding method of austenitic stainless steel plate according to claim 1, characterized in that: In step 3, the preset temperature is above 100°C and the preset vacuum degree is lower than 5×10 -2 Pa.

5. The composite welding method of austenitic stainless steel plate according to claim 1, characterized in that: In the step 4, welding the assembly by electron beam welding comprises: Electron beam tack welding is performed on the I-shaped groove of the assembly with first preset parameters, and the focal position is the surface focal point; The assembly is electron beam welded along the electron beam welding seam of the electron beam tack welding with second preset parameters, and the focus position is the lower focus.

6. The composite welding method of austenitic stainless steel plate according to claim 5, characterized in that: The first preset parameters include: using a beam intensity of 5mA-15mA, a surface moving speed of 3mm / s, a voltage of 150kV, and a working distance of 600mm-1000mm; The second preset parameters include: a beam intensity of 180 mA-230 mA, a surface moving speed of 3 mm / s, a voltage of 150 kV, and a working distance of 600 mm-1000 mm.

7. The composite welding method of austenitic stainless steel plate according to claim 1, characterized in that: The filler wire welding process in step six is ​​one of a laser filler wire welding process and a submerged arc welding process.

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