Welding method for stainless steel precise semi-curved surface seal

Abstract

The invention relates to the technical field of curved surface welding, in particular to a welding method for stainless steel precise semi-curved surface sealing. According to the welding method, firstly, a stainless steel packaging plate is manufactured according to the semi-curved-surface shape of the semi-curved-surface sealing body, welding seams of the packaging plate are reserved on the side face and the end face, then a semi-curved-surface welding and fixing rib tool is manufactured according to the stainless steel packaging plate, and the radian of the curved surface of the welding and fixing rib tool is slightly different from that of the stainless steel packaging plate; the packaging plate is tightly pressed on the sealing body through the clamping device, during welding, side welding seams are welded firstly, then end face side welding seams are welded, then end face back welding seams are welded, and finally end face concave welding seams are welded. By designing the shape of the encapsulation plate, the position of a welding seam, a welding fixing rib tool and the welding sequence and mode, the heat of a welding heat affected zone is effectively controlled, the purpose of controlling welding deformation is achieved, and it is ensured that the encapsulation fitting degree precision after encapsulation welding meets the requirement on the basis that the encapsulation airtightness is met.

Description

Technical Field

[0001] The invention relates to the technical field of curved surface welding, and in particular to a welding method for stainless steel precision semi-curved surface sealing. Background Art

[0002] Components made of stainless steel-coated special material enclosures are often used in specific fields such as aerospace and shipbuilding. The stainless steel enclosure plate fits tightly with the concave curved surface components made of special materials, achieving the corrosion resistance and dimensional accuracy of the components. For semi-curved enclosures, when welding the stainless steel enclosure plate, the concave surface is thermally deformed and bulged, resulting in a large gap between the enclosure and the stainless steel enclosure plate. The dimensional tolerance is a technical problem that needs to be solved in the preparation of this component.

[0003] In the prior art, the welding process is often stabilized by setting a clamping tool. For example, Chinese patent CN106425220A discloses a large curved thin plate welding anti-deformation device and method, in which an inner clamping component and an outer clamping component are provided, and the inner clamping component and the outer clamping component are respectively set on the inner and outer sides of the curved surface of the curved thin plate, and a plurality of outer arc plates and inner arc plates with the same curvature as the curved thin plate are symmetrically provided on the inner and outer clamping components, which can be used to deal with the problem of easy deformation of large curved thin plates during welding. However, when the curvature of the clamping member is the same as that of the thin plate, the holding pressure is relatively uniform, and the gap between the encapsulation body and the stainless steel encapsulation plate cannot be further reduced; Chinese patent CN114571022A discloses a conformal welding method for a planar microstrip plate and a curved metal carrier, which is realized by the following technical scheme: preparing a pre-forming tool and a three-stage elastic pressing tool, the structure is relatively complex, the device has a specific application object, and the gap between the encapsulation body and the stainless steel encapsulation plate cannot be further reduced.

[0004] Therefore, there is a need to provide a simple and easy welding method that can solve the problem that the semi-curved stainless steel package is easy to deform during welding, resulting in poor fit between the package plate and the package body. Summary of the invention

[0005] In order to solve the problems in the prior art of easy deformation of semi-curved stainless steel encapsulation during welding and poor fit between the encapsulation plate and the encapsulation body, the present invention proposes a welding method for stainless steel precision semi-curved encapsulation.

[0006] The method includes sealingly covering a stainless steel encapsulation plate on a semi-curved sealing body, and comprises the following steps:

[0007] Step 1: According to the semi-curved shape of the semi-curved sealing body, a stainless steel encapsulation plate is manufactured, wherein the stainless steel encapsulation plate comprises a stainless steel concave curved surface, a stainless steel back curved surface and two stainless steel end surfaces, wherein the stainless steel concave curved surface comprises a concave surface and two side straight surfaces, wherein the curvature of the stainless steel concave curved surface is R1, and the curvature of the stainless steel back curved surface is R2; welding grooves are reserved on all edges of the stainless steel encapsulation plate; adjacent welding grooves between different stainless steel encapsulation plates form welds, wherein the welds comprise side welds, end face side welds, end face back welds and end face concave welds;

[0008] Step 2: A semi-curved surface welding fixed rib tooling is manufactured according to the stainless steel encapsulation plate, wherein the semi-curved surface welding fixed rib tooling includes a concave fixed rib, a back fixed rib and a straight seam fixed rib, wherein the curvature R3 of the concave fixed rib is greater than R1, and the curvature R4 of the back fixed rib is less than R2;

[0009] Step 3: The stainless steel encapsulation plate is sealed to cover the semi-curved surface sealing body, and the gap between the stainless steel encapsulation plate and the semi-curved surface sealing body at any point is not greater than α0, α0 = 0.05 mm.

[0010] Step 4: The semi-curved surface welding fixed rib tooling is placed close to the stainless steel encapsulation plate, and the semi-curved surface welding fixed rib tooling is clamped by an external clamping device to ensure that the gap between the semi-curved surface sealing body and the stainless steel encapsulation plate at any point is less than α, and α is less than α0;

[0011] Step 5: The welding sequence is to weld the side weld first, then the end face side weld, then the end face back weld, and finally the end face concave weld. After welding, the gap between the stainless steel encapsulation plate and the semi-curved sealing body at any position is no more than 0.05mm, and the air leakage rate is no more than 5x10 -10 Pa m 3 / s.

[0012] Furthermore, in step 1, the thickness of the stainless steel encapsulating plate is 2 mm, the size of the welding groove is 2 mm x 2 mm, the bending accuracy of the stainless steel encapsulating plate is ±0.05 mm, and the bending angle arc is R=4 mm.

[0013] Furthermore, in step 2, the arc length corresponding to R3 is 5-10 mm larger than that of R1, and the arc length corresponding to R4 is 5-10 mm smaller than that of R2.

[0014] Furthermore, in step 4, the distance between the weld and the semi-curved surface welding fixing rib tooling is maintained within the range of 3-5 mm.

[0015] Furthermore, in step 5, the side welds and the end face side welds are welded by a method of first symmetrical spot welding and then symmetrical interval welding, and the end face back welds and the end face concave welds are welded by a method of symmetrical interval welding. The interval welding is to first weld a weld of a certain length, then weld a weld of the same length with a gap of the same distance, and then symmetrically weld the remaining welds after cooling.

[0016] The beneficial effects of the present invention are:

[0017] (1) First, the shape of the stainless steel encapsulating plate is designed to set the weld on the side and end, and the weld is away from the curved concave surface, so as to reduce the conduction of welding waste heat to the semi-curved concave surface of the encapsulating plate during welding, thereby reducing the welding bulging deformation of the stainless steel concave encapsulating plate and ensuring the fitting accuracy;

[0018] (2) Secondly, a semi-curved surface welding fixing rib tooling is designed to ensure that the encapsulation plate and the sealing body can be tightly fitted and fixed to prepare for the welding step. The curvature of the concave surface and the back surface has a certain curvature difference from the stainless steel encapsulation plate, so that it can be pressed more tightly on the stainless steel encapsulation plate, and the gap between it and the semi-curved surface sealing body can be controlled to be smaller; at the same time, the relative position of the semi-curved surface welding fixing rib tooling and the weld is controlled so that the semi-curved surface welding fixing rib tooling is always located in the heat affected zone of the weld, effectively conducting the residual heat of the heat affected zone, reducing welding deformation, and ensuring the fitting accuracy;

[0019] (3) Finally, by first welding the side weld, then the end face back weld, and finally the end face concave weld, the order of the weld heat affected zone is regulated, thereby utilizing the tensile stress of thermal shrinkage deformation. By welding the side weld 1, the back curved surface b shrinks and deforms to be subjected to tensile stress, and the fit with the encapsulation is improved. By welding the end face side weld 2 to fix the end face cover plate, similarly, first welding the end face back weld 3 to utilize the shrinkage deformation to generate tensile stress, and the fit with the encapsulation is improved.

[0020] The method of the present invention is simple, and the prepared semi-curved surface welding fixed rib tooling structure is simple and easy to obtain. By designing the shape of the encapsulation plate, the position of the weld, the welding fixed rib tooling, the welding sequence and method, the heat of the welding heat affected zone can be effectively controlled, and the purpose of controlling the welding deformation is achieved, ensuring that the encapsulation fit accuracy after the encapsulation welding also meets the dimensional accuracy assembly requirements on the basis of meeting the air tightness of the encapsulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The embodiments of the present invention are further described below with reference to the accompanying drawings, in which:

[0022] Figure 1 A schematic diagram of a cross section of a semi-curved sealing body is shown;

[0023] Figure 2 A schematic cross-sectional view of a stainless steel encapsulation plate is shown;

[0024] Figure 3 The semi-curved surface welding fixed rib tooling structure (1) is shown as a cross-sectional schematic diagram and (2) as a three-dimensional schematic diagram;

[0025] Figure 4 A schematic diagram of the welding sequence of the stainless steel encapsulation plate is shown.

[0026] Among them, stainless steel concave surface-a, stainless steel back curved surface-b, stainless steel end face-c, concave fixed ribs-d, back fixed ribs-e, straight seam fixed ribs-f, side weld-1, end face side weld-2, end face back weld-3, end face concave weld-4. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] In one embodiment, the shape data of the semi-curved sealing body is first measured to establish a three-dimensional model and a data tolerance range.

[0029] Step 1: According to the semi-curved shape of the semi-curved sealing body, a stainless steel encapsulation plate is made of 2mm thick 304L stainless steel, wherein the stainless steel encapsulation plate includes a stainless steel concave surface a, a stainless steel back surface b and two stainless steel end surfaces c, wherein the two stainless steel end surfaces c are the upper end surface and the lower end surface respectively. The concave curved surface a of the stainless steel includes a concave surface and two side straight surfaces, the curvature (corresponding arc length) of the concave curved surface of the stainless steel is R1=1980mm, and the curvature (corresponding arc length) of the back curved surface of the stainless steel is R2=2093mm; all edges of the stainless steel encapsulation plate are provided with a 2mmx2mm welding groove, which is an equilateral 2mm triangular inclined surface, and there will be a welding groove (2mmx2mm triangular gap) when two inclined surfaces are connected, and the gap is filled fully during welding; the bending accuracy of the stainless steel encapsulation plate is ±0.05mm, and the bending angle arc R=4mm ensures the fit; the adjacent welding grooves between different stainless steel encapsulation plates form welds, and the welds include side welds 1, end face side welds 2, end face back welds 3 and end face concave welds 4;

[0030] Step 2: A pure copper semi-curved surface welding fixed rib tooling is made according to the stainless steel encapsulation plate, wherein the semi-curved surface welding fixed rib tooling includes a concave fixed rib d, a back fixed rib e and a straight seam fixed rib f, wherein the curvature (corresponding arc length) of the concave fixed rib is R3=1987 mm, and the curvature (corresponding arc length) of the back fixed rib is R4=2087 mm;

[0031] Step 3: The stainless steel encapsulation plate is sealed to cover the semi-curved surface sealing body, and the gap between the stainless steel encapsulation plate and the semi-curved surface sealing body at any point is not greater than α0=0.05 mm.

[0032] Step 4: Place the semi-curved surface welding fixed rib tooling close to the stainless steel encapsulation plate, keep a distance of 3-5 mm between all welds and the corresponding fixed ribs, and clamp the semi-curved surface welding fixed rib tooling through an external clamping device to ensure that the gap between the semi-curved surface sealing body and the stainless steel encapsulation plate at any point is less than α0;

[0033] Step 5: Use argon arc welding, welding current 50-55A, welding wire is made of 304L material with a diameter of 1.2mm, argon gas pressure is 0.1Mpa, the welding order is to weld the side weld 1 first, then weld the end face side weld 2, end face back weld 3 and end face concave weld 4 of the upper end face in sequence, and finally weld the end face side weld 2, end face back weld 3 and end face concave weld 4 of the lower end face in sequence. The side weld 1 and the end face side weld 2 are first symmetrically spot welded and then symmetrically welded at intervals. The end face back weld 3 and the end face concave weld 4 are welded symmetrically at intervals. The intermittent welding method is to first weld a 50mm long weld, then weld at intervals of 50mm, and then weld the remaining 50mm interval welds after cooling. After welding is completed, the gap between the stainless steel encapsulation plate and the semi-curved sealing body at any position is not greater than 0.05mm, and the gas leakage rate is not greater than 5x10 -10 Pa m 3 / s.

[0034] The present invention realizes effective control of the heat of the welding heat affected zone and achieves the purpose of controlling welding deformation by designing the shape of the encapsulation plate, the position of the weld, the welding fixing rib tooling, the welding sequence and method, thereby ensuring that the encapsulation fit accuracy after the encapsulation welding meets the dimensional accuracy assembly requirements while meeting the air tightness of the encapsulation.

[0035] Some exemplary embodiments of the present invention are described above. It can be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention. The features in these embodiments can be recombined in a suitable manner, and the scheme obtained thereby is still within the protection scope required by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without making creative work, that is, all modifications, equivalent substitutions and improvements made within the spirit and principles of this application, fall within the protection scope required by the present invention.

Claims

1. A welding method for stainless steel precision semi-curved surface sealing, wherein the stainless steel sealing plate is sealed and coated on the semi-curved surface sealing body, characterized in that: The following steps are involved: Step 1: According to the semi-curved shape of the semi-curved sealing body, a stainless steel encapsulation plate is manufactured, wherein the stainless steel encapsulation plate comprises a stainless steel concave curved surface (a), a stainless steel back curved surface (b) and two stainless steel end surfaces (c), wherein the stainless steel concave curved surface (a) comprises a concave surface and two side straight surfaces, the curvature of the stainless steel concave curved surface (a) is R1, and the curvature of the stainless steel back curved surface (b) is R2; adjacent welding grooves between different stainless steel encapsulation plates form welds, wherein the welds comprise side welds (1), end face side welds (2), end face back welds (3) and end face concave welds (4); Step 2: A semi-curved surface welding fixed rib tooling is manufactured according to the stainless steel encapsulation plate, wherein the semi-curved surface welding fixed rib tooling comprises a concave fixed rib (d), a back fixed rib (e) and a straight seam fixed rib (f), wherein the curvature R3 of the concave fixed rib (d) is greater than R1, and the curvature R4 of the back fixed rib (e) is less than R2; Step 3: The stainless steel encapsulation plate is sealed to cover the semi-curved surface sealing body, and the gap between the stainless steel encapsulation plate and the semi-curved surface sealing body at any point is not greater than α0, α0 = 0.05 mm; Step 4: The semi-curved surface welding fixed rib tooling is placed close to the stainless steel encapsulation plate, and the semi-curved surface welding fixed rib tooling is clamped by an external clamping device to ensure that the gap between the semi-curved surface sealing body and the stainless steel encapsulation plate at any point is less than α, and α is less than α0; Step 5: The welding sequence is to first weld the side weld (1), then weld the end face side weld (2), then weld the end face back weld (3), and finally weld the end face concave weld (4). After welding is completed, the gap between the stainless steel encapsulation plate and the semi-curved sealing body at any position is no more than 0.05 mm, and the gas leakage rate is no more than 5x10 -10 Pa m 3 / s.

2. A stainless steel precision semi-curved surface sealing welding method according to claim 1, characterized in that: In step 1, the thickness of the stainless steel encapsulating plate is 2 mm, the size of the welding groove is 2 mm x 2 mm, the bending accuracy of the stainless steel encapsulating plate is ±0.05 mm, and the bending angle arc R=4 mm.

3. A stainless steel precision half-curved surface sealing welding method according to claim 1, characterized in that: In step 2, the arc length corresponding to R3 is 5-10 mm larger than that of R1, and the arc length corresponding to R4 is 5-10 mm smaller than that of R2.

4. A stainless steel precision half-curved surface sealing welding method according to claim 1, characterized in that: In step 4, the distance between the weld and the semi-curved surface welding fixing rib tooling is maintained within a range of 3-5 mm.

5. A stainless steel precision semi-curved surface sealing welding method according to claim 1, characterized in that: In step 5, the side weld (1) and the end face side weld (2) are welded by a method of first symmetrical spot welding and then symmetrical interval welding, and the end face back weld (3) and the end face concave weld (4) are welded by a method of symmetrical interval welding. The interval welding is to first weld a weld of a certain length, then weld a weld of the same length with a gap of the same distance, and then symmetrically weld the remaining welds after cooling.

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