Explosive welding method suitable for large-area metal foil / substrate

Abstract

The explosive welding method suitable for the large-area metal foil / substrate comprises the steps that threads are prefabricated on the periphery of the substrate, holes are formed in the symmetrical positions of the periphery of a wave impedance layer, and a metal foil plate is bonded to the lower surface of a wave impedance plate; the substrate, the supporting plate, the wave impedance plate, the heat absorption layer, the explosive and the detonator are sequentially installed from bottom to top. Wherein the metal foil plate, the wave impedance plate and the heat absorption layer jointly form a combined compound plate; a supporting plate is used for supporting the combined compound plate, a traction wire is adopted to penetrate through a hole in the wave impedance plate, and the traction wire is fixed to a fastener; after prepared explosives are laid on the upper side of the heat absorption layer, fastening pieces are screwed on the base plate, and the tensile force of the traction wires is adjusted through the screwing depth of the fastening pieces till the supporting plate in the middle can be smoothly drawn out; and a detonator is arranged at a detonating point of the explosive. According to the method, the problems of breakage, wrinkling, deformation and ablation of the metal foil plate caused by gap supporting in an explosive welding method are solved; and the welding quality of the metal foil plate and the substrate is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of explosion welding, and in particular relates to an explosion welding method suitable for large-area metal foil / substrate. Background Art

[0002] Explosive welding technology is a solid-phase welding technology that uses explosives to drive metal plates to perform high-speed oblique collision motion, and ultimately forms a metallurgical bond between two metals. The main device for explosive welding consists of a base plate, a composite plate, a gap support, and explosives. Driven by the energy of the explosive, the composite plate is continuously accelerated between the gaps and finally collides with the base plate at high speed to produce a metal jet. The metal jet is accompanied by metal melting, mutual diffusion between atoms, and other phenomena during its movement, ultimately forming a metallurgical bond between the two metals. Among them, the collision speed strictly depends on the collision spacing, so in actual explosive welding operations, highly consistent gap supports are used to ensure consistent spacing.

[0003] Metal foil generally refers to a metal plate with a thickness of less than 200μm. Compared with traditional metal plate explosion welding, metal foil saves materials significantly in the use of metals, especially precious metals, and the use of metal foil can well control production costs. In the actual explosion welding process of metal foil / substrate, the shock wave generated by the explosion of explosives can easily form stress concentration on the surface of the metal foil, which can cause the metal foil to deform or even break. The tensile wave can also cause defects such as cracks, pores, and wrinkles; the high temperature environment at the moment of the explosion can also easily ablate the surface of the metal foil. In this regard, the currently disclosed patents provide some solutions. A patent for a multi-layer tungsten foil explosion welding method for preparing a layered composite material (application number 202210753384.9) replaces the entire tungsten plate with multi-layer tungsten foil. Replacing the tungsten plate with a multi-layer tungsten foil can reduce the kinetic energy loss of the interface, thereby reducing the plastic deformation of the interface. Welding multiple layers of tungsten foil at one time can obtain a thicker tungsten coating; however, this method is complicated and has better implementation devices for other non-hard and brittle metals. Patented method for explosive welding of tungsten foil (application number: 202011236548.8) adds a protective plate on the tungsten foil. The protective plate is made of a metal material with a larger wave impedance than the metal foil. The protective plate can effectively reduce the destructive effect of the tensile wave, but the size of the protective plate is too large compared to the tungsten foil, and more explosives are required, which increases the risk of welding failure to a certain extent. Patented explosive welding device for foil with added pressure transfer layer (application number: 202210035330.9) adds a pressure transfer layer between the explosive and the metal foil, and uses the pressure transfer layer to transfer the energy generated by the explosion to the foil. The main material of the pressure transfer layer is salt. In the high temperature environment of explosive welding, the salt vaporizes and absorbs heat to effectively protect the surface of the metal foil from being burned. At the same time, the pressure transfer layer is simple to make and the cost of salt is low. However, the salt will quickly vaporize during the explosive welding process, and the exposed metal foil is still not enough to withstand the impact load of the explosive welding process. The problem of easy deformation and fracture of the metal foil cannot be effectively solved. At the same time, the gap support also has a certain impact on the quality of the bonding interface.

[0004] The traditional explosion welding method of metal plates uses gap supports to ensure the uniformity of spacing. After the explosion welding is completed, the gap supports generally remain in the bonding interface. However, because the base and composite plates are thick enough and strong enough, the actual impact on the interface bonding performance is relatively small. However, for metal foil plates, due to the thin nature of the metal foil, the gap supports will cause defects such as pores and cracks in the interface, and even interface rupture. The current patent solves the problem of the metal foil surface being easily ablated during the explosion welding process of the metal foil plate, and also reduces the phenomenon of defects such as cracks, pores, and wrinkles on the surface. For small-sized metal foil plates, the metal foil plates are often bonded to the protective plate to ensure the uniformity of the spacing, which can avoid the adverse effects of gap supports. Large-area metal foil plates generally refer to plates with a surface area of ​​more than 1m 2Even if this type of metal foil plate is bonded to the protective plate, the problem of bending and sagging of the metal foil composite plate will only be more serious because the mass of the protective plate is much larger than that of the metal foil plate. Summary of the invention

[0005] The purpose of the present invention is to provide an explosive welding method suitable for large-area metal foil / substrate, which stretches the metal foil composite plate through a strong constraint device to ensure the uniformity of the spacing during the welding process and eliminate the gap support; the welding quality of the composite plate is ensured by installing a functional protective layer; and the amount of explosives is reduced by establishing parameter design criteria.

[0006] The technical solution to achieve the purpose of the present invention is:

[0007] An explosive welding method suitable for large-area metal foil / substrate, comprising:

[0008] Prefabricate threads around the base plate, open holes symmetrically around the wave impedance layer, and bond the metal foil plate to the lower surface of the wave impedance plate;

[0009] The base plate, support plate, wave impedance plate, heat absorption layer, explosives and detonators are installed in sequence from bottom to top; the metal foil plate, wave impedance plate and heat absorption layer together form a composite composite plate; the composite composite plate is supported by the support plate, and a traction wire is passed through the holes on the wave impedance plate, and the traction wire is fixed on the fastener; after laying the configured explosives on the upper side of the heat absorption layer, the fastener is screwed on the base plate, and the tension of the wire is adjusted by the depth of the fastener until the middle support plate can be smoothly pulled out; the detonator is installed at the detonation point of the explosive.

[0010] Compared with the prior art, the present invention has the following significant advantages:

[0011] 1) The wave impedance layer is stretched by a strong constraint device to ensure that the entire composite composite plate will not bend or sag, and the influence of the gap support is eliminated. 2) The installed functional protection layer avoids the deformation and fracture of the metal foil plate caused by sparse waves and impact loads, and also reduces the surface ablation of the metal foil plate. 3) A design criterion for explosive welding parameters suitable for large-area metal foil and substrates is designed to optimize the amount of explosives. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the explosion welding of the metal foil / substrate of the present invention.

[0013] Figure 2 It is a top view of the metal foil / substrate explosion welding device of the present invention.

[0014] Figure 3 It is a graph of the collision velocity of the complex plate changing with time.

[0015] Figure 4 This is a diagram of the explosive welding of Hastelloy foil and steel composite plate.

[0016] In the figure, 1 is foundation, 2 is base plate, 3 is metal foil plate, 4 is support plate, 5 is screw, 6 is iron wire, 7 is wave impedance layer, 8 is heat absorption layer, 9 is explosive, and 10 is detonator. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0018] The present invention proposes an explosive welding method suitable for large-area metal foil / substrate, the main steps of which are as follows:

[0019] Step 1: Before the test, threads need to be prefabricated around the substrate 2, and holes need to be opened symmetrically around the wave impedance layer 7. The substrate 2, support plate 4, wave impedance plate 7 and metal foil plate 3 are polished clean, and the metal foil plate can be polished with sandpaper, and then the surfaces of the substrate 2, metal foil plate 3 and support plate 4 are cleaned with ethanol solution, and then the metal foil plate 3 is bonded to the lower surface of the wave impedance plate 7 with double-sided tape.

[0020] Step 2: Refer to the attached Figure 1 , according to the order of base plate 2, support plate 4, wave impedance plate 7, heat absorption layer 8, explosive 9, and detonator 10, they are installed from bottom to top on the flat foundation 1, wherein the metal foil plate 3, wave impedance plate 7, and heat absorption layer 8 together constitute a combined composite plate; during the process, the combined composite plate is supported by the support plate 4, and the iron wire 6 is passed through the holes on the wave impedance plate 7 and is wound around the screw 5 according to the direction in which the screw 5 is turned; after laying the pre-configured explosive 9 on the upper side of the heat absorption layer 8, the screw 5 is screwed on the base plate 2, and the tension of the iron wire 6 is adjusted by the depth of the screw 5 until the middle support plate 4 can be smoothly pulled out, which indicates that the entire combined composite plate does not bend or sag, and then the detonator 10 is installed at the center edge detonation point.

[0021] Step 3: Explosive configuration, minimum collision velocity of metal jets produced by collision of the same metals Minimum collision pressure σ b is the tensile strength of the metal material, ρ is the density of the metal material, and c is the sound velocity of the metal material; the minimum collision velocity when dissimilar metal materials collide to produce a metal jet In order to ensure that the metal jet is generated by the collision of dissimilar metals, the minimum collision pressure p min The minimum collision pressure p when different metal materials collide to produce metal jet is required min1 and p min2 The maximum value among them, that is, p min =max(p min1 , pmin2 ), c1, c2 are the material sound velocities of the dissimilar metals, ρ1, ρ2 are the material densities of the dissimilar metals; the curve of the actual collision velocity changing with time is a variable acceleration curve, refer to the attached Figure 3 Considering the thinness of the metal foil and the actual forming effect, V pmin 90% of V p , min =90%V pmin As the minimum collision velocity to determine the actual height of the explosive. According to Gurney's formula Determine the mass ratio R of explosive and composite plate, where R = m 炸 / (m 箔 +m 阻 +m 热 ), m 炸 、m 箔 、m 阻 、m 热 They are the masses of explosives, metal foil, wave impedance layer, and heat absorption layer; Gurney energy V D is the detonation velocity of the explosive; γ is a polytropic exponent, which is 3 for emulsion explosives, and m can be obtained. 炸 , the explosive is laid on the heat absorbing layer, and its length and width are the same as the heat absorbing layer. The density of the explosive is known, so the height h of laying the explosive can be obtained immediately. 炸 ; The distance between the metal foil and the substrate is H = 0.2 (h 炸 +h 箔 ), where h 箔 is the thickness of the metal foil plate 3 .

[0022] Step 4: detonate the explosives to complete the explosion welding.

[0023] Wherein, the diameter of the holes on the wave impedance layer is 1 to 2 mm larger than the diameter of the iron wire.

[0024] The number of openings on each side of the wave impedance layer is n=L / 200, where L is the side length of the wave impedance layer, mm. First, holes are opened at the four corners of the wave impedance layer, and a total of n equidistant holes are opened on each side.

[0025] The depth of the threaded hole on the substrate does not exceed the thickness h of the substrate. 基 , the relationship between the external thread diameter d1 of the screw and the combined plate is: mm; m 炸 、m 箔 、m 阻 、m 热 They are the masses of explosive, metal foil, wave impedance layer, and heat absorption layer, kg / m 3 ; Coefficient k1 = 3~8; N is the total number of screws.

[0026] Wherein, the threaded hole is located 50 to 150 mm away from the wave impedance hole.

[0027] Among them, the screw length l1 and the substrate thickness h 基 The relationship is: l1 = h 基 +l0,l0=20~40mm.

[0028] The wave impedance layer is a light, high wave impedance material. The optional high wave impedance metal materials include copper, steel, etc., and its thickness d1 is the same as the thickness of the metal foil plate h. 箔 The relationship is d2=k2h 箔 , coefficient k2=3~10.

[0029] The heat absorbing layer is a cheap material that is easy to decompose, evaporate and melt at high temperature. It can be made of salt, limestone, graphite and other materials. Its thickness d2 is the same as the thickness of the metal foil h. 箔 The relationship is d3=k3h 箔 , coefficient k3=10~30.

[0030] Example

[0031] As attached Figure 1 The schematic diagram of metal foil explosion welding is shown. The base plate 2 is made of steel with a size of 1700mm*1500mm*5mm; the metal foil plate 3 is made of Hastelloy with a size of 1200mm*1000mm*0.2mm; the wave impedance layer 7 is made of steel with a size of 1500mm*1300mm*1mm; the heat absorption layer 8 is made of coarse salt with a size of 1400mm*1200mm*2mm; the explosive 9 is an emulsion explosive with a detonation velocity of about 2800m / s and a density of 0.8g / cm 3 ; The support plate 4 is made of steel, the size of the edge support plate is 1400mm*40mm*2.2mm, the size of the middle support plate is 1700mm*50mm*2mm, and the support plates are installed along the short side of the wave impedance layer; According to the formula in the technical solution, the laying height of the explosives is 10mm and the gap height is 2mm.

[0032] Before installing the explosive welding device, the substrate, wave impedance plate and support plate are polished. The metal foil can be polished with sandpaper to remove the oxide layer on the metal surface; at the same time, the surface of the base and composite plate is cleaned with ethanol solution. The coarse salt is packaged with thin cardboard and tape, and the silver foil plate and wave impedance plate, wave impedance plate and coarse salt plate are bonded in turn with double-sided tape. Before the start of the experiment, one hole is prefabricated at the four corners of the wave impedance plate, a total of 8 pairs of equidistant holes are prefabricated on the long side, and a total of 7 pairs of equidistant holes are prefabricated on the short side. The hole diameter is 3mm, and screw holes suitable for standard M6 screws are prefabricated on the corresponding substrate. The M6 ​​screw is 30mm long, and a trapezoidal thread with a pitch of 2mm needs to be prefabricated on the upper half, and the thread on the lower half remains unchanged. Then follow the attached Figure 1 Install them from bottom to top in the order of 2mm wire 6 through the hole and wrap the two ends tightly around the upper half of the M6 ​​screw. The winding direction is the same as the screw turning direction. After laying the explosives, tighten the screws until the middle support plate can be smoothly pulled out. After pulling out the support plate, ignite the detonator 10 to detonate the explosives.

[0033] After the explosion welding was completed, the Hastelloy alloy and steel were successfully welded. The excess parts were cut off and the surface of the Hastelloy alloy foil was observed. No large-scale fractures, deformations, wrinkles, or ablation were found on the surface of the metal foil.

[0034] The embodiments described in the present invention are only some embodiments of the present invention, not all embodiments, and the patent of the present invention is not limited to the scope described. Based on the content of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of patent protection of the present invention.

Claims

1. An explosive welding method suitable for large-area metal foil / substrate, characterized in that: include: Prefabricate threads around the base plate, open holes symmetrically around the wave impedance layer, and bond the metal foil plate to the lower surface of the wave impedance plate; The base plate, support plate, wave impedance plate, heat absorption layer, explosive and detonator are installed in sequence from bottom to top; the metal foil plate, wave impedance plate and heat absorption layer together form a composite composite plate; the wave impedance layer is used to reduce the destructive effect of the rarefaction wave generated during the welding process and prevent the metal foil plate from deformation and fracture; the heat absorption layer is used to absorb the heat generated by the explosion of the explosive and prevent the metal foil from being burned; Use a support plate to support the combined composite plate, use a traction wire to pass through the holes on the wave impedance plate, and fix the traction wire on the fastener; after laying the configured explosives on the upper side of the heat absorption layer, screw the fasteners on the base plate, and adjust the tension of the traction wire by the depth of tightening the fasteners until the middle support plate can be smoothly pulled out; install detonators at the detonation point of the explosives.

2. The explosive welding method for large-area metal foil / substrate according to claim 1, characterized in that the height h of the explosive is 炸 Obtained through the following process: According to Gurney formula Determine the mass ratio R of explosive and composite plate; Where R = m 炸 / (m 箔 +m 阻 +m 热 ), Gurney V p , min =0.9*V pmin Where V p , min is the minimum collision velocity at the actual explosive height, V pmin is the minimum collision velocity when dissimilar metal materials collide to produce metal jet, p min is the minimum collision pressure, c1 and c2 are the material sound velocities of the dissimilar metals, ρ1 and ρ2 are the material densities of the dissimilar metals, respectively; V D is the detonation velocity of explosives; γ is the polytropic index; m 炸 、m 箔 、m 阻 、m 热 They are the masses of explosive, metal foil, wave impedance layer, and heat absorption layer respectively; Find m 炸 , the length and width of the explosive are the same as the heat absorbing layer, and the height h of laying explosives is obtained 炸 .

3. The explosive welding method for large-area metal foil / substrate according to claim 2 is characterized in that: The height of the gap between the metal foil and the substrate is H = 0.2 (h 炸 +h 箔 ), where h 箔 is the thickness of the metal foil.

4. The explosive welding method for large-area metal foil / substrate according to claim 1 is characterized in that: The fastener is a screw, and the relationship between the external thread diameter d1 of the screw and the combined composite plate is: Coefficient k1 = 3~8; N is the total number of screws.

5. The explosive welding method applicable to large-area metal foil / substrate according to claim 4 is characterized in that: Screw length l1 and substrate thickness h 基 The relationship is: l1 = h 基 +l0, coefficient l0=20~40mm.

6. The explosive welding method applicable to large-area metal foil / substrate according to claim 1, characterized in that: The thickness of the wave impedance plate d1 and the thickness of the metal foil plate h 箔 The relationship is d2=k2h 箔 , coefficient k2=3~10.

7. The explosive welding method applicable to large-area metal foil / substrate according to claim 1, characterized in that: Heat absorption layer thickness d2 and metal foil thickness h 箔 The relationship is d3=k3h 箔 , coefficient k3=10~30.

8. The explosive welding method applicable to large-area metal foil / substrate according to claim 1, characterized in that: The diameter of the holes on the wave impedance layer is 1 to 2 mm larger than the diameter of the traction wire.

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