Manufacturing method of medium and large size double-layer stainless steel thick plate complex curved surface structural member

Abstract

The invention relates to a manufacturing method of a medium and large size double-layer stainless steel thick plate complex curved surface structural member. The manufacturing method comprises the following steps: respectively forming an outer shell, an inner shell, a rib plate, a supporting column and a taper sleeve; the four side faces of the peripheries of the inner shell and the outer shell, welding grooves and supporting column mounting holes are machined, welding grooves of rib plates are machined, and the rib plates comprise outer rib plates close to the outer side and T-shaped rib plates located inside; a T-shaped rib plate is welded on the inner side surface of the inner shell; carrying out low-temperature annealing treatment on the welded inner shell and the T-shaped rib plate; a taper sleeve is welded on the inner shell, and then a shielding block is welded on the taper sleeve; finish machining is conducted on a groove, welded to the shell, of the T-shaped rib plate; riveting the shell and the supporting column, and fixing by spot welding; welding the shell and the supporting column, firstly performing backing weld by using laser welding, and then performing filling by using TIG (Tungsten Inert Gas) welding; vibration aging; by means of the method, the welding efficiency is improved, welding deformation is reduced, and the overall profile precision is guaranteed.

Description

Technical Field

[0001] The invention belongs to the field of manufacturing technology, and in particular relates to a method for manufacturing a medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural part. Background Art

[0002] In the fields of nuclear power and chemical equipment, there are a large number of stainless steel double-layer containers with special curved surfaces. Due to their large size, these parts need to be manufactured in sections. The double-layer stainless steel thick plate complex curved surface structural parts formed after segmentation have complex surfaces and high requirements for weld quality and surface accuracy. They are difficult to manufacture.

[0003] Taking the nuclear fusion vacuum chamber as an example, the nuclear fusion vacuum chamber is a double-layer D-section annular spherical structure with a support column in the middle of the interlayer and a shielding block welded and fixed on the support column. After segmented production, a single component is a double-layer stainless steel thick plate complex curved surface structure. The structure is an inner and outer double-layer complex curved surface structure, which is connected by a rib plate and a support column in the middle. There is a shielding block in the interlayer, which is welded and fixed by a support column. The inner and outer shells are generally 316 series stainless steel thick plates with a thickness of not less than 40mm. The surface accuracy of the inner and outer complex curved surfaces is required to be within ±3mm, the welds are required to be fully penetrated, and the weld quality must meet the highest ISO5817 B-level standard.

[0004] For the ISO5817 B-level standard weld quality requirements of the double-layer stainless steel thick plate complex curved surface structural parts, it is difficult to meet the weld quality requirements by using conventional MAG welding (metal active gas shielded arc welding), and the weld repair rate is very high. However, for plates 40mm and above, the welding efficiency is very low and the welding deformation is very large when using TIG welding (non-metal inert gas shielded arc welding) with high welding quality. Especially when welding the outer shell, due to structural reasons, only single-sided welding and double-sided forming can be performed, and the difficulty of controlling welding deformation will be increased to another level. It is difficult to achieve the surface accuracy requirement of ±3mm for complex curved surface structural parts of the order of 10 meters.

[0005] Based on the above surface accuracy and weld quality requirements, a manufacturing method for double-layer stainless steel thick plate complex curved surface structural parts is urgently needed to solve the above problems. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a manufacturing process method for medium and large-sized double-layer stainless steel thick plate complex curved surface structural parts, which solves the problem of surface accuracy control after welding of double-layer stainless steel thick plate complex curved surface structural parts, and avoids the technical problems of low welding efficiency, excessive deformation, or difficult to control the quality of single MAG welding seam of thick plates.

[0007] The technical solution of the present invention to solve the above technical problems is as follows: A method for manufacturing a medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural part, comprising the following steps: Step 1, respectively forming an outer shell, an inner shell, a rib plate, a support column and a cone sleeve, wherein the outer shell is cut and formed in sections, and the inner shell is integrally molded, and the rib plate includes an outer rib plate close to the outside and a T-shaped rib plate located inside; Step 2: Process the four sides of the inner shell and the outer shell, the welding groove, the support column mounting hole, and the welding groove of the rib plate; Step 3, welding a T-shaped rib plate on the inner side of the inner shell; Step 4, performing low temperature annealing treatment on the welded inner shell and T-shaped rib plate; Step 5, welding the cone sleeve on the inner shell, and then welding the shielding block on the cone sleeve; Step 6, finishing the groove on the T-shaped rib plate welded to the shell; Step 7, rivet the shell and support column, and fix them by spot welding; Step 8, welding the shell and support column, first use laser welding for base welding, and then use TIG welding for filling; Step 9, vibration aging; Step 10: Grind and polish the inner and outer surfaces.

[0008] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: The manufacturing method provided in the present application solves the problem of full penetration of the rib plate weld and the welding and fixing problem of the order of support columns and the shielding block under the spatial curved surface structure by using the outer shell segmentation, the cone sleeve structure and the inner shell positioning with special tooling. Through the welding method of laser welding primer + laser welding filling, laser welding primer with less deformation and a rigid body of a certain thickness are used, and then TIG welding is performed, which not only improves the welding efficiency, but also reduces the welding deformation and ensures the overall surface accuracy.

[0009] Based on the above solution, this application can also be optimized and improved as follows: Preferably, in step 2, a processing allowance is left at the welding grooves between the two sides of the T-shaped rib plate and the shell.

[0010] Preferably, in step 3, the inner shell is pre-fixed with a rigid fixture, and then the T-shaped rib plate is welded.

[0011] Preferably, in step 4, the inner shell and the T-shaped rib plate are annealed at a temperature recommended by the RCC-MR standard, and the temperature is not higher than 425°C.

[0012] Preferably, in step 5, the axial direction of the support column is consistent with the normal direction of the corresponding contact area between the inner shell and the outer shell. Preferably, in step 5, after the cone sleeve is welded, 100% VT and PT tests are performed. After the tests are qualified, the interlayer between the inner shell and the outer shell is cleaned, and then the shielding block is welded. After the shielding block is welded, the interlayer is cleaned again. Preferably, in step 6, the groove processing accuracy of the T-shaped rib is within 0.2 mm.

[0013] Preferably, in step 7, the housing and the support column are riveted to ensure that the assembly clearance between the housing and the T-shaped rib plate is within 0.5 mm, the step difference is within 1 mm, and the clearance between the support column and the mounting hole is within 0.5 mm.

[0014] Preferably, in step 8, laser welding is first used for base welding, and the welding thickness is not less than 20 mm.

[0015] Preferably, after filling with TIG welding, 100% VT, PT and PAUT testing is performed, and the weld quality requirements must meet the ISO5817B grade standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the structure of a medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural member after it is manufactured according to an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the structure from another perspective; Figure 3 Schematic diagram of the structure of the weld groove for laser welding primer and TIG filling. DETAILED DESCRIPTION

[0017] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0018] The present application provides a method for manufacturing a medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural part, which comprises the following steps: Step 1, according to the part structure and the requirements of full penetration of the weld, the components of the complex curved surface structural parts of medium and large-sized double-layer stainless steel thick plates are formed, that is, the outer shell 1, the inner shell 2, the rib plate, the support column 5 and the cone sleeve 7 are formed respectively, wherein the outer shell 1 is cut and formed in sections to form a plurality of independent sheet structures, and the inner shell 2 is integrally molded, and the rib plate includes an outer rib plate 3 close to the outside and a T-shaped rib plate 4 located inside.

[0019] Step 2, process the four sides of the inner shell 2 and the outer shell 1, the welding groove, the support column mounting hole, and the welding groove of the rib plate.

[0020] A machining allowance is left at the welding grooves between the two sides of the T-shaped rib plate 4 and the shell 1 to ensure that the riveting accuracy of the remaining shell 1 can be ensured through subsequent fine machining.

[0021] Step 3, welding the T-shaped rib plate 4 on the inner side of the inner shell 2. The structure of the T-shaped rib plate 4 welded on the inner side of the inner shell 2 is shown in FIG. Figure 1 and 2 shown.

[0022] Among them, the inner shell is fixed in advance with a rigid tooling. Specifically, the anti-deformation tooling is spot welded on the inner side of the inner shell 2 for rigid fixation to control welding deformation. After welding, 100% VT, PT and PAUT inspections are carried out, and the weld quality requirements meet the ISO5817 B-level standard.

[0023] VT stands for Visual Testing, which is a non-destructive testing method that observes the product surface with the naked eye or auxiliary tools (such as magnifying glasses, microscopes, etc.) to check whether the product has visible defects such as scratches, cracks, deformation, etc.

[0024] PT stands for Penetrant Testing, which is a non-destructive testing technology used to detect open defects on the surface of materials, such as cracks, pores, etc. It usually involves applying a penetrant containing a fluorescent or colorant to the surface of the material, and the penetrant will penetrate into the open defect. Then remove the excess penetrant and apply a developer to make the penetrant that has penetrated into the defect visible, thereby detecting the defect.

[0025] PAUT stands for Phased Array Ultrasonic Testing, which is an advanced ultrasonic testing technology that forms and controls the shape, direction and focus of the ultrasonic beam by controlling multiple ultrasonic transmitting and receiving elements to achieve more efficient testing.

[0026] ISO 5817 B-level standard is the quality requirements for molten metal welds of metal materials. It is an international standard applicable to the welding of metal materials including steel, aluminum, titanium and nickel alloys; ISO 5817 B-level weld inspection requirements are that the appearance of the weld should be free of defects, the dimensional error should meet the requirements, there should be no cracks, slag inclusions and holes, the intermetallic inclusions should meet the regulations, there should be no internal defects, and the welding residual stress should meet the requirements.

[0027] Step 4, low-temperature annealing treatment is performed on the welded inner shell 2 and T-shaped rib plate 4, and the temperature is appropriately set in the range of 410±15°C to eliminate part of the welding stress; preferably, annealing is performed at the temperature recommended by the RCC-MR standard, which is not higher than 425°C; the RCC-MR standard provides design and construction rules for mechanical components used under high temperature conditions and affected by significant creep, especially size rules for thin shells.

[0028] Step 5, welding the cone sleeve 7 on the inner shell 2, and then welding the shielding block 6 on the cone sleeve 7. Specifically, the cone sleeve 7 is welded on the inner shell 2 to weld and fix the shielding block 6. The cone sleeve 7 is positioned by a special tooling to ensure the positioning accuracy of the cone sleeve 7. After the cone sleeve 7 is welded, 100% VT and PT tests are performed. After passing the test, the interlayer is cleaned. Then the shielding block 6 is welded on the cone sleeve 7. After the welding is completed, the interlayer is cleaned again.

[0029] Among them, the axial directions of the support columns on the complex curved surface are all normal to the curved surface. Due to structural limitations, the support columns 5 need to be welded last, and the cone sleeve 7 structure is designed for welding the shielding block 6, and is positioned with designed tooling.

[0030] Step 6, fine-machining the groove on the T-shaped rib plate 4 welded to the shell 1; wherein the machining accuracy of the groove on the side of the T-shaped rib is within 0.2 mm.

[0031] Step 7, rivet the shell 1 and the support column 5, and fix them by spot welding; specifically, the shell 1 and the support column 5 are riveted to ensure that the assembly clearance between the shell 1 and the T-shaped rib plate 4 is within 0.5mm, the step difference is within 1mm, and the clearance between the support column 5 and the mounting hole is within 0.5mm, so as to ensure the requirements of the subsequent laser welding for the assembly clearance and step difference.

[0032] Step 8, welding the shell 1 and the support column 5, first use laser welding for base welding, and then use TIG welding for filling; after welding, 100% VT, PT and PAUT inspection are carried out, and the weld quality is required to meet the ISO5817 B-level standard. The welding groove of laser welding base welding + TIG filling is V-shaped, and the angle is about 55°. Figure 3 shown.

[0033] Step 9, vibration aging; Vibrating Stress Relief (VSR) is a technology used to reduce and adjust the residual stress inside the material. It controls the excitation frequency of the vibrator to make the workpiece resonate, produce appropriate alternating motion and absorb part of the energy, resulting in microscopic viscoelastic-plastic mechanical changes inside the workpiece, thereby reducing the local peak stress of the workpiece and homogenizing the residual stress field of the workpiece, especially the stress concentration area on the surface.

[0034] Step 10: Grind and polish the inner and outer surfaces.

[0035] The ribs inside the sandwich between the inner shell 2 and the outer shell 1 are designed as T-shaped ribs for butt welding with the outer shell, while the ribs close to the four sides can be welded on one side through the gap in the sandwich.

[0036] The structural diagram of the medium and large size double-layer stainless steel thick plate complex curved surface structural parts after forming in this application is as follows Figure 1 shown.

[0037] The above manufacturing method solves the problem of full penetration of the rib plate weld and the welding and fixing problem of the order of support columns and the shielding block under the spatial curved surface structure by segmenting the outer shell 1, the cone sleeve 7 structure and the inner shell 2 using special tooling for positioning. Through the welding method of laser welding primer + laser welding filling, laser welding primer with less deformation is used, and a rigid body of a certain thickness is formed, and then TIG welding is performed, which not only improves the welding efficiency, but also reduces the welding deformation and ensures the overall surface accuracy.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts, characterized in that: The steps include: Step 1, respectively forming an outer shell, an inner shell, a rib plate, a support column and a cone sleeve, wherein the outer shell is cut and formed in sections, and the inner shell is integrally molded, and the rib plate includes an outer rib plate close to the outside and a T-shaped rib plate located inside; Step 2, processing the four sides of the inner shell and the outer shell, the welding grooves, the support column mounting holes, and the welding grooves of the rib plates, wherein the rib plates include the outer rib plates close to the outside and the T-shaped rib plates located inside; Step 3, welding a T-shaped rib plate on the inner side of the inner shell; Step 4, performing low temperature annealing treatment on the welded inner shell and T-shaped rib plate; Step 5, welding the cone sleeve on the inner shell, and then welding the shielding block on the cone sleeve; Step 6, finishing the groove on the T-shaped rib plate welded to the shell; Step 7, rivet the shell and support column, and fix them by spot welding; Step 8, welding the shell and support column, first use laser welding for base welding, and then use TIG welding for filling; Step 9, vibration aging; Step 10: Grind and polish the inner and outer surfaces.

2. The method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts according to claim 1 is characterized in that: In step 2, a processing allowance is left at the welding grooves between the two sides of the T-shaped rib plate and the shell.

3. The method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts according to claim 1, characterized in that: In step 3, the inner shell is fixed in advance with a rigid tooling, and then the T-shaped rib plate is welded.

4. The method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts according to claim 1, characterized in that: In step 4, the inner shell and the T-shaped rib plate are annealed according to the temperature recommended by the RCC-MR standard, and the temperature is not higher than 425°C.

5. The method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts according to claim 1, characterized in that: In step 5, the axial direction of the support column is consistent with the normal direction of the corresponding contact area between the inner shell and the outer shell.

6. The method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts according to claim 1, characterized in that: In step 5, after the cone sleeve is welded, 100% VT and PT tests are performed. After the tests are qualified, the interlayer between the inner shell and the outer shell is cleaned, and then the shielding block is welded. After the shielding block is welded, the interlayer is cleaned again.

7. The method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts according to claim 1, characterized in that: In step 6, the groove processing accuracy of the T-shaped rib is within 0.2mm.

8. The method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts according to claim 1, characterized in that: In step 7, the housing and the support column are riveted together to ensure that the assembly clearance between the housing and the T-shaped rib plate is within 0.5 mm, the step difference is within 1 mm, and the clearance between the support column and the mounting hole is within 0.5 mm.

9. The method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts according to claim 1, characterized in that: In step 8, laser welding is first used for base welding, and the welding thickness is not less than 20 mm.

10. The method for manufacturing medium-to-large-sized double-layer stainless steel thick plate complex curved surface structural parts according to claim 9, characterized in that: After filling with TIG welding, 100% VT, PT and PAUT testing is carried out, and the weld quality requirements must meet the ISO5817B grade standard.

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