A welding structure and method for dissimilar metal structural components

Abstract

This invention relates to a welding structure and method for dissimilar metal structural components, belonging to the field of plate welding technology. It solves the technical problem of obtaining dissimilar metal structural components on the surface of equipment when direct explosive welding or hot-pressing composite fabrication is unsuitable. A welding structure for dissimilar metal structural components includes a substrate of a first metal material and metal elements of a second metal material welded onto the substrate; wherein the first metal material and the second metal material are different, being dissimilar metal materials; the welding structure includes an intermediate structural component formed by an intermediate structural layer of the second metal material and the substrate material; the welding structure also includes welding blocks. The bonding strength of the welding structure of this invention reaches at least 90% of the bonding strength of conventional through-welds of the same material, meeting the welding strength requirements of specific industrial applications.

Description

Technical Field

[0001] This invention belongs to the field of plate welding technology, and specifically relates to a welding structure and method for dissimilar metal structural components. Background Technology

[0002] Dissimilar metal structural components composed of two or more different materials, such as composite material structures used in ships and aerospace, can improve durability, reduce weight and production costs, or meet functional requirements, such as cooling. Such dissimilar metal structural components are composed of the base material of the ship or aircraft and one or more dissimilar metal materials different from the base material. Dissimilar metal structural components are part of the large structure of the ship or aircraft.

[0003] Fusion welding between dissimilar metals can result in residual stress and severe brittle intermetallic compounds, making laser and electron beam fusion welding unsuitable for joining dissimilar metals. Explosive welding and thermocompression bonding are solid-state bonding processes, commonly used to join dissimilar metals, or via riveting and bolting. Explosive welding creates the weld seam through high-speed impact on the workpiece without significantly increasing the temperature of any workpiece, thus avoiding the drawbacks of heat-dependent fusion welding. Therefore, explosive welding is considered suitable for joining dissimilar metals. However, explosive welding is limited by poor process controllability; the violent impact during explosive welding can be destructive to the welding materials. It is only suitable for the overall welding of multi-layered metal planar or cylindrical plate components within a certain size range, and is not suitable for combinations of complex surface structures or for welding assembly on the surfaces of pre-formed large or precision equipment.

[0004] Hot-pressing composite technology involves applying high pressure at a suitable temperature below the melting point of the matrix alloy. Through plastic deformation, creep, and diffusion with the matrix, the matrix and reinforcement are tightly bonded together, resulting in a fully compacted metal matrix composite material. Hot-pressing composite processes generally require the bonding surfaces to be planar or curved surfaces with minimal curvature, and are performed in high-temperature, high-pressure equipment. The bonded materials must withstand high temperatures and pressures. Therefore, for equipment with complex surface structures, or large or precision pre-fabricated equipment, it is not convenient to place them in high-temperature hot-pressing composite equipment for the fabrication of dissimilar metal structural components. Furthermore, the drilling required for riveting or bolting connections exposes the composite interface of dissimilar metals to the working environment, making the composite surface susceptible to corrosion.

[0005] Therefore, the aforementioned methods are clearly not feasible for directly fabricating dissimilar metal structural components using explosive welding or hot pressing on complex surface structures or on already formed large or precision equipment. Thus, how to assemble dissimilar metal structural components on complex surface structures or on already formed large or precision equipment becomes a technical problem to be solved. Summary of the Invention

[0006] Based on the above analysis, this invention proposes a welding structure and method for dissimilar metal structural components to solve the technical problem of installing dissimilar metal structural components with different materials from the base material on the surface of equipment when the surface structure is complex or the large or precision equipment is not suitable for direct explosive welding or hot pressing composite preparation of dissimilar metal structural components.

[0007] The objective of this invention is mainly achieved through the following technical solutions: The present invention provides a welding structure for a dissimilar metal structural component, the dissimilar metal structural component comprising a substrate of a first metal material and metal components of a second metal material welded onto the substrate; wherein the first metal material and the second metal material are different and are dissimilar metal materials. The welded structure includes an intermediate structural component formed by an intermediate structural layer of the same material as the base material and a metal element of the second metal material, wherein the intermediate structural layer side of the intermediate structural component is attached to the base side. The welded structure also includes a welded block disposed on the other side of the substrate opposite to the said one side; the welded block is formed by multiple weld points evenly distributed; the contact surface between the weld points and the substrate forms a weld, and the weld formed by each weld point is an independent closed curved surface.

[0008] Furthermore, the depth h of the solder joint area is greater than the thickness t2 of the substrate, but less than the total thickness T of the substrate and the intermediate structural layer.

[0009] Furthermore, the depth h of the solder joint area and the thickness t2 of the substrate, and the thickness t3 of the intermediate structural layer are related as follows: t2 + 0.1t3 < h < t2 + 0.8t3.

[0010] Furthermore, the shapes of the weld area include circles, ellipses, annular rings, and rectangular annular rings, and correspondingly, the shapes of the weld seams include cylindrical surfaces, elliptical cylindrical surfaces, annular cylindrical surfaces, and rectangular annular cylindrical surfaces.

[0011] Furthermore, when the shape of the solder joint area is elliptical, the diameter d of the solder joint area is the length of the major axis.

[0012] Furthermore, the multiple weld points within the welding block are arranged in a circular, elliptical, rectangular, or polygonal shape.

[0013] Furthermore, within the welding block, there is a relationship between the diameter d of the weld area, the edge spacing s between adjacent weld areas, the thickness t2 of the substrate, and the thickness t3 of the intermediate structural layer: 0.4 + 0.2t2 / t3 <d / s<1.0+0.2t2 / t3。

[0014] Furthermore, there is a relationship between the diameter d of the solder joint area, the edge spacing s between adjacent solder joint areas, the thickness t2 of the substrate, and the thickness t3 of the intermediate structural layer: 0.5 + 0.2t2 / t3 <d / s<0.9+0.2t2 / t3。

[0015] The present invention also provides a welding method for dissimilar metal structural components, comprising: first, using explosive welding or hot-pressing composite method to combine metal elements with an intermediate structural layer to form an intermediate structural component; then, using laser or electron beam welding to weld the intermediate structural layer side and the substrate side of the intermediate structural component together, wherein the welding includes welding from the opposite side of the substrate to the substrate side.

[0016] Furthermore, laser or electron beam welding includes one or more of the following: spot welding forming methods, scanning welding forming methods, and filler welding forming methods.

[0017] Compared with the prior art, the present invention can achieve at least one of the following technical effects: (1) When combining large ships or body structures with dissimilar metal structures of different materials, the technical methods of surface welding of dissimilar metals, such as explosive welding and hot pressing composite, cannot be utilized. In this invention, the intermediate structural layer and metal components are first combined into an intermediate structural component by explosive welding or hot pressing composite processes. Then, the intermediate structural component and the substrate are combined again by laser or electron beam welding. The preparation of dissimilar metal structural components is achieved by using two or more welding processes.

[0018] (2) The welding structure of the present invention connects the intermediate structural component and the base body together through several welding blocks. Each welding block consists of several welding point areas. The weld of each welding point area is an independent closed curved surface. Adjacent welding point areas and welding blocks are distributed at intervals on the base material according to certain rules. Even if cracks occur in several welding point areas, the expansion of cracks can be effectively suppressed because the base material is separated.

[0019] (3) The depth of the weld point area in the intermediate structural component area of ​​the welding structure of the present invention does not exceed the thickness of the intermediate structural layer, that is, the weld point area does not penetrate the interface between the intermediate structural layer and the metal component in the intermediate structural component, thereby suppressing the generation of intermetallic compounds during the welding process and ensuring the performance of the plate.

[0020] (4) In the welding operation of this invention, horizontal welding is performed and the weld area extends vertically downwards. The metal plate on the unwelded side of the dissimilar metal structural component can be prevented from sagging under its own weight. This structure allows for the suppression of protrusions on the unwelded side even when the material being welded is made by rough machining methods such as cast material. Therefore, welding can be performed appropriately even if the object being welded is made of cast material or the like.

[0021] (5) The bonding strength of the welded structure of the present invention reaches at least 90% of the bonding strength of conventional through-weld of the same material, which meets the requirements for welding strength in specific industrial applications.

[0022] (6) This invention provides a method for determining explosive welding process parameters by calculating the base plate spacing according to the conservation of function and the flux thickness according to the conservation of momentum. This invention opens up a new way of thinking for determining explosive welding process parameters.

[0023] Other features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0024] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0025] Figure 1 A top-view schematic diagram of a welded structure for dissimilar metal structural components; Figure 2 A longitudinal section diagram of the weld area for welding dissimilar metal structural components; Figure 3 This is a schematic diagram of a welding forming method; Figure 4 This is an assembly diagram of the intermediate structural component of the aluminum-copper composite laminar flow plate prepared by explosive welding in Example 1; Figure 5 This is a longitudinal section view of the weld area of ​​the electron beam welded aluminum-copper composite laminar flow plate in Example 1; Figure 6 This is a longitudinal section view of the weld area of ​​the laser-welded titanium-steel composite plate in Example 2; Figure 7 A longitudinal section of the weld area of ​​the electron beam welded aluminum-copper composite laminar flow plate for Comparative Example 1, and a magnified view of a portion thereof. Figure 8 The image shows a longitudinal section of the weld area of ​​the electron beam welded aluminum-copper composite laminar flow plate for Comparative Example 2. In the figure, 1-welded structure, 2-surface welded layer, 3-inner welded layer, 4-weld, 5-weld spot area, 6-welded block, 7-hull, 8-intermediate structural component, 9-metal component, 10-welding device, 11-launching part, 12-control part, 13-high-energy beam, 14-covering plate, 15-copper tube, 16-substrate. d - Diameter of solder joint area 5, s - Edge spacing between adjacent solder joint areas 5, h - Depth of solder joint area 5, T - Total thickness of surface solder layer 2 and inner solder layer 3, D - Diameter of solder block 6, t2 - Thickness of surface solder layer 2, t3 - Thickness of inner solder layer 3, a - Fixed-point welding forming method, b - Scanning welding forming method, c - Filling welding forming method, B - Width of substrate 16, L - Spacing between copper tubes 15, m - Spacing between the center line of copper tube 15 and substrate 16. Detailed Implementation

[0026] The following detailed description of a welding structure and method for dissimilar metal structural components, with reference to specific embodiments, is provided. These embodiments are for comparative and illustrative purposes only, and the present invention is not limited to these embodiments.

[0027] Composite material structures are widely used in shipbuilding and aerospace, primarily to improve durability, reduce weight and production costs, or to meet functional requirements such as cooling. These dissimilar metal structural components are formed by combining the base material of a ship or aircraft with one or more dissimilar metal materials. These dissimilar metal structural components are an integral part of the larger structure of the ship or aircraft. Welding technology is used in shipbuilding and aircraft manufacturing to connect large structures. Welding methods for connecting materials with different metallurgical properties are particularly important. For example, if the base material of an aircraft is aluminum or titanium, a steel plate needs to be connected to a portion of the aluminum or titanium base material for mechanical purposes. Laser or electron beam welding cannot directly weld dissimilar metals across the entire surface, while explosive welding and hot-pressing composite methods are difficult to use for connecting large, complex surface structures of aircraft. Riveting or bolt connections require drilling, which exposes the aluminum / steel or titanium / steel composite interfaces to the working environment, making them susceptible to corrosion. Due to the heat dissipation requirements, a certain ship needs to install a composite laminar flow plate with fluid heat dissipation pipes on the surface of a portion of the ship's aluminum plate substrate. The heat dissipation pipes are made of copper. Existing fusion welding technologies, such as laser or electron beam welding, cannot weld the copper heat dissipation pipes to the ship's aluminum plate. Explosive welding and hot-pressing composite welding, which are used for welding dissimilar metals, cannot be carried out on ships due to process and welding equipment requirements.

[0028] Therefore, this invention provides a welding structure and method for dissimilar metal structural components. The dissimilar metal structural components include a substrate of a first metal material and metal elements of a second metal material welded onto the substrate. The first metal material and the second metal material are different, being dissimilar metal materials. The welding structure 1 includes an intermediate structural component formed by an intermediate structural layer of the same material as the substrate and the metal elements of the second metal material. The intermediate structural layer side of the intermediate structural component is attached to one side of the substrate. The welding structure 1 also includes a welding block 6 disposed on the opposite side of the substrate. The welding block 6 is formed by multiple weld point areas 5 evenly distributed. The contact surface between the weld point area 5 and the substrate forms a weld seam 4, and the weld seam 4 formed by each weld point area is an independent closed curved surface. It should be noted that the substrate is a ship or aircraft hull, and the weld point area 5 is located on the exposed side of the substrate, i.e., welding is performed from one side of the substrate towards the intermediate structural layer side; that is, the substrate is the surface welding layer 2, and the intermediate structural layer is the internal welding layer 3.

[0029] Figure 1 This is a plan view of the welded structure of the dissimilar metal structural component of the present invention. It should be noted that the surface weld layer 2 of the present invention belongs to the cabin 7 of a ship or aircraft. The surface weld layer 2 is a single layer of metal, which can be a single metal or an alloy, such as iron, copper, aluminum, titanium, or their alloys, steel, etc. The inner weld layer 3 is the intermediate structural layer of the intermediate structural component 8. Below the inner weld layer 3 is a metal element 9 of a second metal material. Together, they form the intermediate structural component. The surface weld layer 2 and the inner weld layer 3 are welding substrates of the same material.

[0030] The thickness of the substrate, i.e., the surface weld layer 2, is t2, and the thickness of the intermediate structural layer, i.e., the internal weld layer 3, is t3. The thickness range of t2 and t3 is 1~30 mm, preferably 2~20 mm, where t2≤t3. The total thickness of the two is t2+t3=T. The depth h of the weld area 5 is greater than the thickness t2 of the surface weld layer 2 and less than the total thickness T of the surface weld layer 2 and the internal weld layer 3. Specifically, t2+0.1t3<h<t2+0.8t3.

[0031] Specifically, within welding block 6, the spacing 's' of weld point areas 5 represents the distance between the edges of adjacent weld point areas. The shape of weld point areas 5 is generally circular, but can also be elliptical, annular, or rectangular depending on the characteristics of the welding surface. Correspondingly, the shape of the weld includes cylindrical, elliptical cylindrical, annular cylindrical, and rectangular annular cylindrical surfaces. The maximum spacing between the contour edges of weld point areas 5 is taken as the diameter 'd' of weld point areas 5. That is, if it is elliptical, the diameter 'd' of weld point areas 5 is the length of the major axis of the ellipse; if it is rectangular annular, the diameter 'd' of weld point areas 5 is the length of the diagonal of the outer ring rectangle. The diameter 'd' of weld point areas 5 ranges from 0.5 to 80 millimeters. Furthermore, the diameter 'd' of each weld point area 5 does not need to be strictly the same.

[0032] The number of welding spot areas 5 in the welding block 6 is 2 or more, the plurality of welding spot areas 5 in the welding block 6 are uniformly distributed, generally arranged in a circular shape, and may also be oval, rectangular or polygonal, such as hexagonal or triangular lattice arrangement. Therefore, the shape of the welding block 6 formed by the welding zone boundaries of the plurality of welding spot areas 5 is generally also circular, and may of course also be oval, rectangular, a suitable curve, or polygonal. In Figure 1 , the welding block 6 is a circle with a diameter D, but can also be regarded as a square with a side length D, so as to facilitate planning the welding of welding spots according to a certain arrangement, and can also be connected dispersedly according to specific shapes.

[0033] It should be noted that for this multi-layer metal structural member welded by laser or electron beam, stress tends to concentrate at the boundary between the weld seam and the base material, therefore, cracking may occur at the boundary between the weld seam and the base material. More seriously, if simple linear welding is adopted and the boundary is in the same direction as the crack propagation direction, the crack will tend to develop further, and if this happens, the welded materials connected together may break. Therefore, in the welding block 6, there is a relationship among the diameter d of the welding spot area 5, the edge spacing s between the welding spot area 5 and the adjacent welding spot area 5, the thickness t2 of the base body, that is, the surface welding layer 2, and the thickness t3 of the intermediate structural layer, that is, the internal welding layer 3: 0.4+0.2t2 / t3<d / s<1.0+0.2t2 / t3, preferably 0.5+0.2t2 / t3<d / s<0.9+0.2t2 / t3.

[0034] When the ratio d / s of the diameter d of the welding spot area 5 to the edge spacing s between the welding spot area 5 and the adjacent welding spot area 5 is d / s≤0.4+0.2t2 / t3, the diameter d of the welding spot area 5 is too small relative to the spacing s between adjacent welding spot areas, and the welding bearing capacity per unit area is insufficient. Therefore, when a load exceeding the strength of each individual welding spot area 5 is applied, fracture may occur, and in this case, each welding spot area 5 fractures internally separately.

[0035] When d / s≥1.0+0.2t2 / t3, the diameter d of the welding spot area 5 is too large relative to the spacing s between adjacent welding spot areas, the distribution of welding spot areas 5 is too dense. Under the condition of applying a certain external load, cracks between adjacent welding spot areas are easily extended and connected to each other after being stressed, therefore, continuous fracture occurs along the periphery of the weld seam 4. At the same time, large-thickness materials require higher energy for penetration, and the composite interface is more easily affected, therefore it is necessary to reduce the density of welding spot areas 5.

[0036] When 0.4+0.2t₂ / t₃<d / s<1.0+0.2t₂ / t₃, the diameter d of the welding spot area 5 has an appropriate dimension relative to the spacing s between adjacent welding spot areas, so the propagation of cracks generated in the welding spot area 5 along the weld 4 is suppressed. Moreover, adjacent welding spot areas 5 are not too far apart, so the sharing of the mechanical load by adjacent welding spot areas 5 also suppresses the individual fracture of each welding spot area 5.

[0037] Furthermore, according to the ratio t₂ / t₃ of the thickness t₂ of the surface welding layer 2 to the thickness t₃ of the inner welding layer 3 and the diameter d of the welding spot area 5, further optimization within the above range avoids mutual influence between the weld and the composite interface, enabling the surface welding layer 2 and the inner welding layer 3 of the welded object to disperse the acting force, which helps to improve the bonding strength.

[0038] According to the area, structure and morphology of the welding surface of the dissimilar metal structural member to be welded, the welding block 6 can be divided into one or more blocks. The relative positions and distances between multiple blocks are determined according to the area, structure and morphology of the welding surface. Specifically, multiple welding blocks 6 may be arranged in parallel or alternately, etc., and the spacing between two adjacent welding blocks 6 is greater than the edge spacing s between adjacent welding spot areas 5 within the welding block 6.

[0039] The present invention also provides a welding method for dissimilar metal structural members. First, a metal element 9 made of a second metal material and an intermediate structural layer made of a first metal material are combined to form an intermediate structural member 8 by methods such as explosion welding or hot-pressing composite, and the material of the intermediate structural layer is the same as that of a base body. The base body belongs to a cabin body 7, and the cabin body 7 is composed of a single-layer or multi-layer metal including the base body.

[0040] Then, the intermediate structural layer side of the intermediate structural member 8 and one side of the base body are welded and combined by laser welding or electron beam welding, and the welding includes performing welding from the other side of the base body opposite to the one side of the base body.

[0041] Specifically, the above welding method includes: Step 1, combining the metal element 9 and an intermediate structural layer made of the same material as the base body by explosion welding or hot-pressing composite method to form the intermediate structural member 8; Step 2, fitting and welding the intermediate structural layer side of the intermediate structural member 8 and one side of the base body by laser welding or electron beam welding, performing welding from the other side of the base body opposite to the one side of the base body, so as to prepare the dissimilar metal structural member; Specifically, in step 1, the present invention provides a method for determining explosion welding process parameters, comprising the following steps: Step I, selecting the one of the metal element 9 and the intermediate structural layer with smaller mass per unit area as the cladding plate in explosion welding, and the other one with larger mass per unit area as the base plate in explosion welding, wherein the base plate and the cladding plate are arranged in parallel; Step II: Determine the impact velocity V during explosive welding based on the material parameters of the substrate and the cover plate. c The optional range; Step III: Based on the material parameters of the substrate and the cladding, determine the welding energy required for welding. Use the kinetic energy of the cladding as the welding energy source, and determine the impact velocity V of the cladding during explosive welding based on the minimum welding energy requirement. p Minimum value V pmin The range of values ​​for the collision angle θ is determined by referring to the fourth strength theory and welding energy requirements, and then the collision angle θ and the collision point velocity V are determined. c Impact velocity of the cover plate V p The specific value; Step IV: Based on the impact velocity V of the cover plate p Collision angle θ, explosive detonation velocity V d The physical parameters of the substrate and the cladding plate and the explosive are used to calculate the distance A between the substrate and the cladding plate based on the principle of conservation of energy. Step V: Based on the impact velocity V of the cover plate p Explosive detonation velocity V d Based on the physical parameters of the covering plate and explosive, and the principle of conservation of momentum, the thickness ζ of the explosive charge is calculated.

[0042] It should be noted that in step I, when the unit area mass of metal element 9 and intermediate structural layer are equal, either one can be selected as the cover plate or substrate for explosive welding.

[0043] Specifically, in step II, the velocity V at the collision point is determined. c Optional range: Collision point velocity V c Minimum value V cmin =(2R e (HV) f +HV b ) / (ρ f +ρ b )) 1 / 2 (1) In equation (1), R e HV is the Reynolds number, usually taken as 10.6; HV is the Vickers hardness. f The Vickers hardness of the cladding, HV b ρ is the Vickers hardness of the substrate. f ρ is the density of the cladding. b The density of the substrate. The collision point velocity V. c The maximum value V cmax It is the minimum of the sound velocity of the cladding and the sound velocity of the substrate.

[0044] In step III, the welding energy is directly proportional to the kinetic energy of the cladding plate, and the lower limit of the welding energy is related to the impact velocity V of the cladding plate. pMinimum value V pmin The following relationship exists between them: 1 / 2MV pmin 2 =E wmin =σ b SH f βδ (2) In equation (2), M is the mass of the cladding plate, M = SH f ρ f S is the area of ​​the cover plate, which is generally the welding area, ρ f H is the density of the cladding. f V represents the thickness of the cladding. pmin The minimum impact velocity of the cladding is 1 / 2MV. pmin 2 For the minimum kinetic energy of the impact plate, E represents the conversion rate of the impact kinetic energy of the cladding plate into welding energy. wmin σ is the lower limit of welding energy. b Where S is the tensile strength of the cladding or substrate material, S is the welding area, which is generally the area of ​​the cladding, and β is the minimum weld layer thickness as a percentage of the cladding thickness H. f The ratio, δ, represents the elongation of the weld layer, which is generally between the elongation of the cladding and the substrate. Here, σ is used. b SH f βδ roughly represents the fracture energy required to achieve the standard weld strength and minimum weld layer thickness, so it is used to approximate the minimum welding energy required for welding, i.e., the lower limit of welding energy E. wmin The minimum weld layer thickness is the minimum thickness of the weld layer when the weld reaches the standard weld strength, which is related to the physicochemical and mechanical properties of the base and cladding welding materials.

[0045] It should be noted that when the materials of the cladding plate and the substrate are the same, the standard welding strength required for welding is the tensile strength of that material, and the welding energy is the fracture energy of the minimum weld layer. As can be seen from equation (2), the impact velocity V of the cladding plate p Minimum value V pmin =[2σ b βδ / ( ρ f )] 1 / 2 It should be noted that, based on previous research, the V-shape within the welding window... pmin Approximately and σ b ρ f This implies that, within the microsecond range of explosive welding, the conversion rate of the impact kinetic energy of the cladding plate into welding energy is... The conversion rate is related to the elongation δ of the material; that is, a higher elongation results in a higher conversion rate, and a lower elongation results in a lower conversion rate. It is approximately equivalent to 2βδ, therefore we have: V pmin =(σ b / ρ f ) 1 / 2 (3).

[0046] When the substrate and cladding materials are different, there is V pmin =(σ b1 / ρ f ) 1 / 2 (4) In equation (4), σ b1 It has the highest tensile strength among base and cladding materials.

[0047] Specifically, when set in parallel configurations, the detonation velocity V of the explosive is... d and the velocity V at the point of collision c Equal, the velocity V at the point of collision c Impact velocity of the cover plate V p There is a V between them p =2V c Since the collision angle θ is small, 2sin(θ / 2) = sinθ, so generally we have V p =V c sinθ. During explosive welding, the velocity V at the point of impact. c The maximum value V cmax Minimum value V corresponding to the impact velocity of the cover plate pmin Therefore, the minimum collision angle θ is obtained. min =arcsin(V) pmin / V cmax ).

[0048] Furthermore, set V c sinθ(2-cosθ) 1 / 2 =V pmin (2-cosθ) min ) 1 / 2 V can be obtained c The correspondence between V and θ yields a V value representing the lower limit of welding energy. c The numerical lines of θ are the isoenergy lines of the lower limit of welding energy.

[0049] Set V c sinθ(2-cosθ) 1 / 2 =kV pmin (2-cosθ) min ) 1 / 2 If k is a number between 2 and 4, such as 3, then V can be obtained. c The correspondence between V and θ yields a V that represents the upper limit of welding energy. cThe numerical lines of θ are the isoenergy lines of the upper limit of welding energy. The isoenergy lines of the upper and lower limits of welding energy, and V... cmax V cmin The boundary lines together form the welding parameter window.

[0050] Furthermore, determine the specific value of the collision angle θ: Collision angle θ=θ min +n(θ) max -θ min (5) In equation (5), n is an adjustment coefficient, which is a number between 0 and 1, such as 0.5.

[0051] It should be noted that the typical collision angle θ ranges from 3° to 30°.

[0052] Furthermore, based on the already determined specific value of the collision angle θ, the explosive welding parameters V... c The velocity V at the collision point is determined within the -θ window. c The specific value.

[0053] Furthermore, based on the determined collision angle θ and the collision point velocity V... c According to formula V p =V c sinθ, the impact velocity V of the cover plate is obtained. p .

[0054] In step IV, the formula for conservation of function is: P C-J k0SA / cos(θ / 2)=1 / 2MV p 2 (6) In equation (6), P C-J denoted as CJ, where C is the pressure on the wavefront of the explosive detonation wave; k0 is the pressure adjustment coefficient, ranging from 0.6 to 0.7; S is the area of ​​the cladding plate; A is the distance between the substrate and the cladding plate; θ is the collision angle; M is the mass of the cladding plate; and V is the mass of the cladding plate. p The impact velocity of the cladding plate.

[0055] Specifically, P C-J =ρ0V d 2 / (γ+1)(7) In equation (7), ρ0 is the density of the explosive, and V d For the detonation velocity of the explosive, V d The properties of the explosive itself determine the influence of V. d Factors generally include explosive density, explosive ratio, explosive package size, moisture content, particle size, and additives; γ is the adiabatic index of the explosion products. It should be noted that when the base plate and cover plate are arranged parallel to each other, the collision point velocity V... cand the detonation velocity V of explosives d They are equal, so when choosing the explosive detonation velocity V... d Reference collision point velocity V c To make the two similar, or to refer to the detonation velocity V of explosives. d Calculate the velocity V at the point of impact. c .

[0056] In step V, the formula for conservation of momentum is ΓζSρ0V d =MV p (8) In equation (8), ζ is the thickness of the explosive charge, S is the area of ​​the covering plate, ρ0 is the density of the explosive charge, and V d V is the detonation velocity of the explosive, M is the mass of the cladding plate, and V is the mass of the cla p Let Γ be the impact velocity of the cladding plate, and Г be the ratio of the momentum of the explosive acting in the direction of the cladding plate to the total momentum of the explosive. γ is the adiabatic index of the explosion products, N is the length of the cladding plate, and N ≥ 2.25ζ is satisfied.

[0057] It should be noted that all material parameters in the above formulas are in the International System of Units (SI), and the unit of Vickers hardness HV is Pa.

[0058] In step 2, a welding block 6 is formed on the other side of the substrate. The welding block 6 is formed by multiple welding point areas 5 evenly distributed. The contact surface between the welding point area 5 and the substrate forms a weld 4. The weld 4 formed by each welding point area 5 is an independent closed curved surface. The thickness t2 of the substrate is less than or equal to the thickness t3 of the intermediate structural layer. The depth h of the solder joint area 5 is greater than the thickness t2 of the substrate and less than the total thickness T of the substrate and the intermediate structural layer. The diameter d of the solder joint area 5, the edge spacing s between adjacent solder joint areas 5, and the thicknesses t2 of the substrate and t3 of the intermediate structural layer are related by the following formula: 0.4 + 0.2t2 / t3 <d / s<1.0+0.2t2 / t3。

[0059] Specifically, the intermediate structural component 8 and the substrate are welded using laser or electron beam welding, achieved through a welding device 10. This welding device 10 includes at least one emitting section 11 and a control section 12. The control section 12 controls the emitting section 11 to emit a high-energy beam 13 at a predetermined position on the surface welding layer 2 to be welded, so that the weld point area 5 is formed at the position irradiated by the high-energy beam 13. The laser welding power range is 1000~1400W; the electron beam welding voltage range is 140~150kV, and the vacuum degree is less than 7×10⁻⁶. -2 Pa.

[0060] Figure 2 A longitudinal section diagram of the weld area for welding dissimilar metal structural components. Figure 2The cabin 7 is composed of multiple layers of metal. The bottom layer of the cabin 7 is the base. Before welding, the metal layer on the base corresponding to the welding area needs to be removed to facilitate welding from top to bottom. At the same time, the thickness t2 of the base, i.e., the surface welding layer 2, needs to meet the requirements, i.e., the range of t2 is 1~30 mm, preferably 2~20 mm. The thickness t2 of the surface welding layer 2 is not greater than the thickness t3 of the middle structural layer, i.e., the inner welding layer 3. Before welding, the surfaces of the surface welding layer 2 and the inner welding layer 3 need to be polished together.

[0061] It should be noted that if the joint surface between the internal welded layer 3 and the underlying metal element 9 in the intermediate structural component 8 is wavy, sawtooth, or other undulating, the thickness t3 of the internal welded layer 3 does not include the undulating part of the joint surface.

[0062] During welding, the weld point 5 penetrates the surface weld layer 2 and welds with the inner weld layer 3. The contact surface between the weld point 5 and the substrate is the weld seam 4. The surface weld layer 2 and the inner weld layer 3 of the materials being welded are connected together by the weld seam 4. The depth h of the weld point 5 is greater than the thickness t2 of the surface weld layer 2 and less than the total thickness T of the surface weld layer 2 and the inner weld layer 3. Specifically, t2 + 0.1t3 < h < t2 + 0.8t3. The depth h of each weld point 5 does not need to be strictly the same.

[0063] When h ≥ t2 + 0.8t3, under the high-temperature environment of welding, a new phase—intermetallic compound—may form at the interface between the inner weld layer 3 and the dissimilar metal component 9 below. Due to the uncertainty of the mechanical properties of the new phase and the discontinuity between the phases, defects and cracks are generated, which will propagate along the weld area 5, making the weld 4 more prone to failure.

[0064] When h≤t2+0.1t3, the bonding depth of the weld area 5 between the surface weld layer 2 and the inner weld layer 3 is insufficient, and the welding strength does not meet the requirements.

[0065] When t2+0.1t3<h<t2+0.8t3, the bonding depth of the weld area 5 between the surface weld layer 2 and the inner weld layer 3 is within a reasonable range, and the weld area 5 is blocked by the metal of the inner weld layer 3, so it will not form intermetallic compounds that degrade performance with the dissimilar metal components 9 under the inner weld layer 3. Even if cracks occur at the interface between the weld area 5 and the welding substrate, the substrate can absorb some of the fracture energy, thus improving the fracture resistance.

[0066] It should be noted that since the thickness ranges of t2 and t3 are 1~30 mm, and the range of 0.1t3 is 0.1~3 mm, in actual welding, the depth of the weld point area 5 entering the inner weld layer 3 needs to be selected according to the thickness of t2, but it will not exceed the range of t2+0.1t3<h<t2+0.8t3.

[0067] Furthermore, during horizontal welding operations, the weld area extends vertically downwards, and the metal components of the intermediate structural member 8 that are not involved in welding can prevent the weld area 5 from sagging under its own weight. This structure allows for the suppression of protrusions on the unwelded side, even when the material being welded is made using rough machining methods such as cast material. Therefore, welding can be performed appropriately even if the object being welded is made of cast material or the like.

[0068] The laser or electron beam welding of the present invention includes one or more of the following: a fixed-point welding forming method, a scanning welding forming method, and a filler welding forming method.

[0069] Specifically, the fixed-point welding forming method emits a high-energy beam 13 at a predetermined point on the surface welding layer 2 for a fixed period of time, causing the irradiated area to melt in a hole-like manner, thereby forming a circular weld point area 5. More specifically, the control unit 12 controls the emission unit 11 to aim the high-energy beam 13 at the predetermined position range of the weld point area 5 on the surface welding layer 2 for irradiation, forming an internally melted weld point area 5. Figure 3 Figure 'a' illustrates the fixed-point welding forming method. It should be noted that, due to the limited irradiation range of the high-energy beam, the diameter of the weld area formed by fixed-point forming is relatively small.

[0070] Specifically, the scanning welding forming method forms the weld point area 5 by scanning the outer circumference of the weld point area 5 along a circumferential path using a high-energy beam 13. More specifically, the control unit 12 controls the emission unit 11 so that the high-energy beam 13 scans the outer circumference of the predetermined weld point area 5 on the surface welding layer 2 along a circumferential path, forming a circumferentially melted annular weld point area 5. Figure 3 Figure b illustrates the scanning welding forming method, with the arrow indicating the direction of movement of the high-energy beam 13. It should be noted that the diameter of the weld area 5 is not limited by the scanning welding forming method; the direction of scanning along the circumferential path is unrestricted, and can be clockwise, counterclockwise, or a combination of both.

[0071] Specifically, the filling welding forming method involves using a high-energy beam 13 to scan the outer circumference of the weld point area 5 along a circumferential path to form an annular block. Then, the high-energy beam 13 is repeatedly oscillated and scanned to melt the annular block, filling its interior and forming a partially or completely melted weld point area 5 within the annular block. More specifically, the control unit 12 controls the emission unit 11 to cause the high-energy beam 13 to scan the outer circumference of the predetermined weld point area 5 on the surface welding layer 2 along a circumferential path to form an annular block; then, the control unit 12 controls the emission unit 11 to cause the high-energy beam 13 to repeatedly oscillate and scan to melt the annular block, filling its interior and forming a filled weld point area 5. Figure 3 Figure c illustrates the filler welding method, and the wave oscillation in the figure represents the swinging movement of the high-energy beam 13. It should be noted that, like the scanning welding method, the filler welding method allows for an unrestricted increase in the diameter of the weld area 5; the direction of scanning along the circumferential path is also unrestricted, and can be clockwise, counterclockwise, or a combination of both.

[0072] It should be noted that during actual welding, one of the above three welding forming methods can be used, or two or more of the above welding methods can be used in combination. In addition, the irradiation time of the high-energy beam should preferably be such that the depth h of the weld area 5 is greater than the thickness t2 of the surface weld layer 2, but less than the total thickness T of the surface weld layer 2 and the inner weld layer 3.

[0073] Through the above welding method, the intermediate structural component 8 and the base body are connected together by several welding blocks. Each welding block consists of several weld points. Adjacent weld points and welding blocks are distributed at intervals on the base material. Even if cracks occur in several weld points, the propagation of cracks can be effectively suppressed due to the separation of the base materials. This makes the bonding strength of the welded structure of the present invention reach at least 90% of the bonding strength of conventional through-welds of the same material, which meets the requirements for welding strength in specific industrial applications.

[0074] Example 1 A welding method for an aluminum-copper composite laminar flow plate with fluid heat dissipation pipes on a ship includes the following steps: Step 1: Using explosive welding process, an aluminum-copper composite laminar flow plate intermediate structure with fluid heat dissipation pipes is prepared by detonating an explosive-aluminum plate-gap-copper tube array-gap-aluminum plate structure from top to bottom. The top aluminum plate, i.e. the cover plate, is the intermediate structural layer. Specifically, step 1 involves determining the process parameters for explosive welding according to the following steps: Step I: In this embodiment 1, the metal element 9 is a composite structure composed of copper tubes and aluminum plates. The material and size of the intermediate structural layer are the same as those of the aluminum plate in the metal element 9. The copper tube array of the metal element 9 is sandwiched between the aluminum plate in the metal element 9 and the aluminum plate of the intermediate structural layer. The aluminum plate, copper tube array, and aluminum plate are arranged in parallel. Since the aluminum plates on both sides are the same size, in this embodiment 1, either aluminum plate can be used as a cover plate in the explosive welding process.

[0075] Specifically, the cladding plate 14 is an aluminum plate with dimensions of 200 mm × 100 mm × 4 mm; the substrate structure includes an aluminum plate serving as substrate 16 and an array of copper tubes laid on it. The copper tube array consists of 5 independent copper tubes 15, located between the cladding plate 14 and the substrate 16. The aluminum plate serving as substrate 16 has dimensions of 200 mm × 100 mm × 4 mm, meaning the width of substrate 16 is B = 100 mm. The copper tubes 15 are 200 mm long, with an outer diameter of 3 mm and a wall thickness of 1 mm. The copper tubes 15 are evenly laid on substrate 16 at a spacing of L = 10 mm. The surfaces of cladding plate 14 and substrate 16 are polished and cleaned with 400-grit sandpaper, and the copper tubes are filled with paraffin wax.

[0076] In this embodiment 1, theoretically, there are welding processes between the cladding plate and the copper tube, the copper tube and the substrate, and the cladding plate and the substrate in the explosive welding process. However, the copper tube is suspended above the substrate with a gap between them. When the cladding plate initially falls, it will not weld with the suspended copper tube. When the cladding plate contacts the substrate, the copper tube is sandwiched in it and will weld with the substrate and the cladding plate to a certain extent. However, this is different from explosive welding in the true sense. Moreover, the key point of welding aluminum-copper composite laminar flow plates is that the welding strength of the substrate and the cladding plate needs to meet the requirements. Therefore, only the process parameters required for welding the cladding plate and the substrate are calculated.

[0077] Step II: Determine the impact velocity V during explosive welding based on the material parameters of the substrate and the cover plate. c The optional range; Calculate the welding V of the cover plate and the substrate c Optional range: Collision point velocity V c Minimum value V cmin =(2R e (H) f +H b ) / (ρ f +ρ b )) 1 / 2 = (10.6 × 2 × 0.294 × 10) 9 / 2700) 1 / 2 =1520 (m / s); Collision point velocity V c The maximum value V cmax It is 6400 meters per second.

[0078] Step III: Based on the material parameters of the substrate and the cladding, determine the welding energy required for welding. Use the kinetic energy of the cladding as the welding energy source, and determine the impact velocity V of the cladding during explosive welding based on the minimum welding energy requirement. p Minimum value V pmin The range of values ​​for the collision angle θ is determined by referring to the fourth strength theory and welding energy requirements, and then the collision angle θ and the collision point velocity V are determined. c Impact velocity of the cover plate V p The specific value; Determine the impact velocity V of the cover plate p Minimum value V pmin =(σ bf / ρ f ) 1 / 2 =(1×10 8 / 2700) 1 / 2 =192 m / s; Minimum collision angle θ min =arcsin(192 / 6400)=1.72°; Given k=3, the maximum collision angle θ is obtained. max =21.6°; Determine the specific value of the collision angle θ: The collision angle θ = 1.72° + 0.51 × (21.6° - 1.72°) = 11.9°. First, according to the formula: V c2 sinθ(2-cosθ) 1 / 2 =3V pmin (2-cosθ) min ) 1 / 2 Find the velocity V at the point of collision. c2 =2766 m / s, then according to the formula: V c =1520 + 0.056 × (2766 - 1520) = 1600 m / s, find the velocity V at the point of impact. c ; Impact velocity of the cover plate V p =V c sinθ=1600×sin11.9°=330 meters / second.

[0079] Step IV: Based on the impact velocity V of the cover plate p Collision angle θ, explosive detonation velocity V d The physical parameters of the substrate and the cladding plate and the explosive are used to calculate the distance A between the substrate and the cladding plate based on the principle of conservation of energy. According to formula 1 / 2MV p 2 Calculate the kinetic energy, E, of the copper tube with a cladding and paraffin filling as it falls onto the plate. k=13656 joules, explosive density is 800 kg / m³, detonation velocity V d Referring to the above collision point velocity V c V d The value is taken as 1600 m / s, k0 is taken as 0.6, γ=2, and the explosion pressure P on the cladding plate is P=P C-J k0S=ρ0V d 2 / (γ+1)k0S=800×1600×1600×0.6×0.02 / 3=8192000 Newtons, according to the formula P C-J k0SA / cos(θ / 2)=1 / 2MV p 2 The calculation shows that the base plate spacing A = 0.002 meters. Since there is a copper tube with an outer diameter of 3 mm sandwiched in the middle, the actual base plate spacing is 5 mm. Specifically, the lower outer edge of the copper tube is 1 mm away from the substrate, that is, the center line of copper tube 15 is 2.5 mm away from the substrate. The upper outer edge of the copper tube is 1 mm away from the cover plate, that is, the center line of copper tube 15 is 2.5 mm away from the cover plate.

[0080] Step V: Based on the impact velocity V of the cover plate p Explosive detonation velocity V d The physical parameters of the covering plate and explosive are used to determine the explosive thickness ζ based on the conservation of momentum. The formula for conservation of momentum is ΓζSρ0V d =MV p , We find that ζ = 0.015 meters, which means the thickness of the medicine is 15 millimeters.

[0081] Figure 4 This is an assembly diagram of the intermediate structural component of the aluminum-copper composite laminar flow plate prepared by explosive welding in Example 1.

[0082] Step 2: Electron beam welding is used to weld the intermediate structural component of the aluminum-copper composite laminar flow plate to a large area aluminum plate of the ship's hull to obtain the aluminum-copper composite laminar flow plate.

[0083] The area where the composite laminar flow plate intermediate structural component is installed on a large aluminum plate on the ship is polished and cleaned with 400-grit sandpaper to obtain an aluminum plate layer of 200 mm × 100 mm × 2 mm as the surface welding layer 2, that is, the thickness t2 of the surface welding layer 2 is 2 mm; the inner welding layer 3 is the cover plate during the explosive welding in step 1, that is, the intermediate structural layer, with an aluminum plate of 200 mm × 100 mm × 4 mm in size, and the thickness t3 of the inner welding layer 3 is 4 mm.

[0084] Electron beam welding was used, with a voltage of 150kV and a vacuum degree of 5×10⁻⁶. -2Pa. A fixed-point welding forming method is adopted, and welding is performed from a large-area aluminum plate. The weld point area penetrates the large-area aluminum plate and enters the intermediate structural layer, thereby forming a welded block on the surface of the large-area aluminum plate. The welded structure is a rectangular welded block formed by four evenly distributed weld point areas. The side length of the welded block is 100 mm × 80 mm, and the diameter d of the weld point area is 28 mm. In the long side direction of the rectangular welded block, the distance s between adjacent weld point areas is 44 mm, and d / s is 0.64. In the short side direction of the rectangular welded block, the distance s between adjacent weld point areas is 24 mm, and d / s is 1.17. The diameter d of the weld point area is 28 mm, and the depth h of the weld point area is 5 mm. Figure 5 The image shows a longitudinal section of the weld area of ​​the electron beam welded aluminum-copper composite laminar flow plate in Example 1. As can be seen from the image, the influence range of the weld area in the depth direction is limited to the inner weld layer, and it does not have the physical conditions to generate intermetallic compounds. The weld strength was tested and found to reach 95% of the penetration weld strength of the aluminum plate.

[0085] Example 2 A welding method for large-area titanium-steel composite plates on aircraft includes the following steps: Step 1: The titanium steel intermediate structural component is prepared by hot pressing composite method. The area of ​​the titanium steel intermediate structural component is 310 mm × 270 mm. The titanium plate on one side of the titanium steel intermediate structural component is the intermediate structural layer with a thickness of 20 mm, that is, the thickness t3 of the internal welding layer is 20 mm. Step 2: Use laser welding to weld and combine the titanium-steel intermediate structural components and the large-area titanium plates on the aircraft to prepare titanium-steel composite plates; The surface of a large titanium plate on the aircraft is treated to obtain a surface welding layer 2 with dimensions of 310 mm × 270 mm × 2 mm, that is, the thickness t2 of the surface welding layer 2 is 2 mm. Welding process: Laser welding is used with a power of 1400W, a welding speed of 0.03 m / s, and a defocusing amount of +5 mm.

[0086] Welding Forming Method: A filler welding forming method is adopted, where welding is performed from a large-area titanium plate. The weld points penetrate the large-area titanium plate and enter the intermediate structural layer, thus forming a welded block on the surface of the large-area titanium plate. The welded structure is a square welded block formed by four evenly distributed weld points. The side length D of the welded block is 240 mm, the diameter d of the weld point area is 70 mm, the spacing s between adjacent weld points is 100 mm, the d / s ratio is 0.7, and the depth h of the weld point area is 10 mm. Figure 6 The image shows a longitudinal section of the weld area of ​​the laser-welded titanium-steel composite plate in Example 2. As can be seen from the image, the influence of the weld area in the depth direction is limited to the inner weld layer, and it does not have the physical conditions to generate intermetallic compounds. The welding strength was tested and found to reach 100% of the penetration weld strength of the titanium plate.

[0087] Comparative Example 1 The same materials and processes as in Example 1 were used for comparison, except that the depth h of the solder joint area was 5.8 mm, and h ≥ t2 + 0.8t3. Figure 7 The image shows a longitudinal section of the weld area of ​​the electron beam welded aluminum-copper composite laminar flow plate for Comparative Example 1, along with a magnified view of its portion. As can be seen from the image, the influence range of the weld area in the depth direction extends beyond the inner weld layer, and the heat-affected zone reaches the surface of the copper tube beneath the aluminum plate of the inner weld layer. The magnified view shows that a welding crack appeared between the contact surface of the aluminum plate and the copper tube, indicating that the hot-melt welding process damaged the aluminum-copper composite layer.

[0088] Comparative Example 2 A comparison was made using the exact same materials and processes as in Example 1, except that the weld depth h was 2.3 mm, h ≤ t2 + 0.1t3, indicating insufficient weld depth. Figure 8 The image shows a longitudinal section of the weld area of ​​the electron beam welded aluminum-copper composite laminar flow plate for Comparative Example 2. The weld strength only reached 50% of the penetration weld strength of the aluminum plate.

[0089] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A welding method for dissimilar metal structural components, characterized in that, The welding method is used to prepare a welded structure for realizing the dissimilar metal structural component. The dissimilar metal structural component includes a base material of a first metal material, an intermediate structural layer of the same material as the base material, and a metal element (9) of a second metal material. The first metal material is different from the second metal material and is a dissimilar metal material. The welded structure (1) includes an intermediate structural component (8) formed by explosive welding of the metal element (9) of the second metal material and the intermediate structural layer of the same material as the base material. The intermediate structural layer side of the intermediate structural component (8) is bonded to the base side by laser or electron beam welding. The welded structure (1) also includes a welding block (6) set on the other side of the base opposite to the first side. The welding block (6) is formed by a plurality of weld point areas (5) evenly distributed. The contact surface between the weld point area (5) and the base material forms a weld (4). The weld (4) formed by each weld point area (5) is an independent closed curved surface. The welding method includes: first, using explosive welding to combine the metal element (9) with the intermediate structural layer to form an intermediate structural component (8); then, using laser or electron beam welding to weld the intermediate structural layer side and the substrate side of the intermediate structural component (8) together, wherein the laser or electron beam welding includes welding from the opposite side of the substrate to the substrate side. When using explosive welding to form the intermediate structural component (8), the method for determining the explosive welding process parameters includes the following steps: Step 1: Select the metal component (9) and the intermediate structural layer with the smaller unit area mass as the cover plate in the explosive welding, and the other component with the larger unit area mass as the base plate in the explosive welding. The base plate and the cover plate are set in parallel. Step II, according to the material parameters of the substrate and the cladding plate, determine the collision point velocity V when explosive welding c optional range; Step III: Based on the material parameters of the substrate and the cladding, determine the welding energy required for welding. Use the kinetic energy of the cladding as the welding energy source, and determine the impact velocity V of the cladding during explosive welding based on the minimum welding energy requirement. p Minimum value V pmin V pmin =(σ b1 / ρ f ) 1 / 2 In the formula σ b1 ρ is the highest tensile strength among base and cladding materials. f The density of the cladding plate is determined, and the range of values ​​for the collision angle θ is determined with reference to the fourth strength theory and welding energy requirements. This leads to the determination of the collision angle θ and the collision point velocity V. c Impact velocity of the cover plate V p The specific value; Step IV, according to the impact velocity V of the cover plate p , the impact angle θ, the explosive detonation velocity V d , and the physical parameters of the cover plate and the explosive, the distance A between the substrate and the cover plate is calculated according to the principle of functional conservation. Step V, according to the velocity of the cover plate V p , the explosive detonation velocity V d , and the physical parameters of the cover plate and the explosive, the charge thickness ζ is calculated according to the principle of momentum conservation.

2. The welding method according to claim 1, characterized in that, The depth h of the solder joint area (5) is greater than the thickness t2 of the substrate and less than the total thickness T of the substrate and the intermediate structural layer.

3. The welding method according to claim 2, characterized in that, The depth h of the solder joint area (5) and the thickness t2 of the substrate and the thickness t3 of the intermediate structural layer are related as follows: t2+0.1t3<h<t2+0.8t3.

4. The welding method according to claim 1, characterized in that, The shape of the weld area (5) includes a circle, an ellipse, a ring and a rectangular ring, and the shape of the weld (4) corresponding to this includes a cylindrical surface, an elliptical cylindrical surface, a ring cylindrical surface and a rectangular ring cylindrical surface.

5. The welding method according to claim 4, characterized in that, When the shape of the solder joint area (5) is elliptical, the diameter d of the solder joint area (5) is the length of the major axis.

6. The welding method according to claim 1, characterized in that, The multiple weld points (5) within the welding block (6) are arranged in a circular, elliptical, rectangular or polygonal pattern.

7. The welding method according to claim 1, characterized in that, Within the welding block (6), there is a relationship between the diameter d of the weld joint area (5), the edge spacing s between adjacent weld joint areas (5), the thickness t2 of the substrate, and the thickness t3 of the intermediate structural layer: 0.4 + 0.2t2 / t3 <d / s<1.0+0.2t2 / t3。 8. The welding method according to claim 7, characterized in that, The diameter d of the solder joint area (5), the edge spacing s between adjacent solder joint areas (5), the thickness t2 of the substrate, and the thickness t3 of the intermediate structural layer are related as follows: 0.5 + 0.2t2 / t3 <d / s<0.9+0.2t2 / t3。 9. The welding method according to claim 1, characterized in that, The laser or electron beam welding includes one or more of the following: spot welding forming method, scanning welding forming method, and filler welding forming method.

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