A design method of explosive welding process parameters

Abstract

The present application relates to a kind of explosive welding process parameter design method, belong to explosive welding technical field, solve the technical problem of reasonable determination base cladding spacing and charge thickness in explosive welding process.A kind of explosive welding process parameter design method, including the following steps: step 1, according to the mass of unit area of welding material determines the base layer and cladding in explosive welding, and the base layer and cladding are arranged in parallel;Step 2, determine the optional range of collision point speed V c When explosive welding;Step 3, determine the minimum value V p Of cladding impact velocity V pmin , and determine the value range of collision angle θ, further determine the specific value of collision angle θ, collision point speed V c And cladding impact velocity V p ;Step 4, determine the spacing A between base layer and cladding based on the principle of conservation of function;Step 5, determine the charge thickness ζ based on the principle of conservation of momentum.The present application opens up a kind of new path to determine base cladding spacing and charge thickness, more scientific than existing empirical formula.

Description

Technical Field

[0001] This invention belongs to the field of explosive welding technology, and specifically relates to a method for designing explosive welding process parameters. Background Technology

[0002] Explosive welding is a process that uses the energy impact of an explosive explosion to fuse two metal plates together. Explosive welding is a solid-state welding process; the weld seam is created through high-speed impact on the workpiece without significantly increasing the temperature of any workpiece, and the substrate does not undergo large-scale melting. In contrast, fusion welding, used for joining dissimilar metals, produces residual stress and severe brittle intermetallic compounds, making it unsuitable for welding dissimilar metals. Therefore, explosive welding can weld not only the same type of metal but also offers unique advantages over fusion welding for welding dissimilar metals.

[0003] Based on the current research status of explosive welding, the design of explosive welding process parameters is still in the exploratory stage, and most of them are empirical formulas. The designed process parameters have uncertainty for the welding effect. For example, the welding effect is unstable with changes in the type and / or size of the welding material, explosives, etc. Summary of the Invention

[0004] In view of the current research status of explosive welding, this invention proposes a design method for explosive welding process parameters to solve the technical problem of rationally determining the substrate-coating spacing and flux thickness in explosive welding process, and provides a new approach for those skilled in the art.

[0005] The objective of this invention is mainly achieved through the following technical solutions:

[0006] This invention provides a method for designing explosive welding process parameters, comprising the following steps:

[0007] Step 1: Determine the base layer and cladding layer in explosive welding based on the unit area mass of the welding material, and set the base layer and cladding layer in parallel.

[0008] Step 2: Determine the impact velocity V during explosive welding based on the material parameters of the base layer and the coating layer. c The optional range;

[0009] Step 3: Based on the material parameters of the base layer and the cladding layer, determine the welding energy required for welding. Use the kinetic energy of the cladding layer as the welding energy source, and determine the impact velocity V of the cladding layer 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 and coating impact velocity V p The specific value;

[0010] Step 4: Based on the coating impact velocity V p Collision angle θ, explosive detonation velocity V d The physical parameters of the base layer and the explosive are used to determine the spacing A between the base layer and the base layer based on the conservation of function.

[0011] Step 5: Based on the coating impact velocity V p Explosive detonation velocity V d The physical parameters of the coating and explosive are used to determine the thickness ζ of the explosive charge based on the conservation of momentum.

[0012] Furthermore, in step 1, a flat plate or round tube with a smaller unit area mass is selected as the cladding layer in explosive welding, and a flat plate or round tube with a larger unit area mass is selected as the base layer in explosive welding. When the unit area mass of the flat plate or round tube is equal, either one is selected as the cladding layer or base layer in explosive welding.

[0013] Furthermore, in step 2, the velocity V at the point of collision c Minimum value V cmin satisfy:

[0014] V cmin =(2R) e (HV f +HV b ) / (ρ f +ρ b )) 1 / 2

[0015] In the formula: R e Here is the Reynolds number, with a value of 10.6; HV f HV represents the Vickers hardness of the coating, measured in Pascals (HV). b ρ is the Vickers hardness of the substrate, measured in Pascals; f ρ is the density of the coating, expressed in kilograms per cubic meter. b The density of the base layer is expressed in kilograms per cubic meter.

[0016] Collision point velocity V c The maximum value V cmax This is the minimum sound velocity of the overlay and the base layer, expressed in meters per second.

[0017] Furthermore, in step 3, the welding energy and the kinetic energy of the cladding are directly proportional, and the lower limit of the welding energy and the impact velocity V of the cladding are related. p Minimum value V pmin The following conditions must be met:

[0018] 1 / 2MV pmin 2 η = E wmin =σ b SHf βδ

[0019] Where: M is the mass of the coating, in kilograms; S is the area of ​​the coating, in square meters; ρ f H represents the density of the coating, expressed in kilograms per cubic meter. f Coating thickness, in meters; 1 / 2MV pmin 2 E represents the minimum kinetic energy of the cladding impact, measured in joules; η represents the conversion rate of the minimum kinetic energy of the cladding impact into welding energy. wmin The lower limit of welding energy is expressed in joules; σ b β represents the tensile strength of the cladding or base layer material, measured in Pascals; β is the minimum weld layer thickness as a percentage of the cladding thickness H. f The ratio, δ, is the elongation of the weld layer, expressed as a percentage and dimensionless.

[0020] Furthermore, in step 3, the stress failure criterion of the fourth strength theory is (σ 2 +3τ 2 ) 1 / 2 ≥σ S σ represents the dynamic compressive normal stress between the cladding and the base layer, measured in Pascals. σ and the impact velocity V of the cladding are also mentioned. p Longitudinal velocity component V perpendicular to the base layer p cos(θ / 2) is directly proportional to the stress; τ is the shear stress between the cladding and the base layer, in Pascals; τ is related to the impact velocity V of the cladding. p lateral velocity component V parallel to the base layer p sin(θ / 2) is directly proportional; where θ is the collision angle; (σ 2 +3τ 2 ) 1 / 2 The dynamic compressive equivalent stress is expressed in Pascals; σ S The maximum dynamic yield strength in the cladding and base layer is expressed in Pascals.

[0021] Furthermore, when V p (2-cosθ) 1 / 2 ≥V pmin (2-cosθ min ) 1 / 2 At that time, the dynamic compression equivalent stress (σ) 2 +3τ 2 ) 1 / 2 The dynamic yield strength σ of the overcoat and base layer has been reached or exceeded. S ;

[0022] Among them, V p V is the impact velocity of the coating. pmin The impact velocity of the coating is V pThe minimum value, in meters per second; θ is the collision angle, θ min The minimum collision angle is expressed in degrees.

[0023] Furthermore, the maximum value of the dynamic compressive equivalent stress is the dynamic yield strength σ corresponding to the lower limit of the welding energy. S 2 to 4 times.

[0024] Furthermore, in step 4, the formula for the conservation of function is P. C-J k0SA / cos(θ / 2)=1 / 2MV p 2 In the formula P C-J V is the pressure on the wavefront CJ of the explosive detonation wave, in Pascals; k0 is the pressure adjustment coefficient, ranging from 0.6 to 0.7; S is the cladding area, in square meters; A is the distance between the base layer and the cladding layer, in meters; θ is the impact angle, in degrees; M is the cladding mass, in kilograms; V p The value represents the impact velocity of the coating, measured in meters per second.

[0025] Furthermore, in step 5, the formula for conservation of momentum is ΓζSρ0V. d =MV p In the formula, ζ is the thickness of the explosive charge, in meters; S is the area of ​​the coating, in square meters; ρ0 is the density of the explosive, in kilograms per cubic meter; V d V is the detonation velocity of the explosive, measured in meters per second; M is the cladding mass, measured in kilograms; V p Γ represents the impact velocity of the cladding layer, measured in meters per second; Γ is the ratio of the momentum of the explosive acting in the direction of the cladding layer to the total momentum of the explosive.

[0026] Furthermore, In the formula, γ is the adiabatic index of the explosive products, which is dimensionless; ζ is the thickness of the explosive charge, in meters; N is the length of the coating, in meters, and N≥2.25ζ.

[0027] Compared with the prior art, the present invention can achieve at least one of the following technical effects:

[0028] (1) This invention designs explosive welding process parameters based on energy balance and applies welding energy to analyze the energy conversion problem in explosive welding, providing a new approach for determining explosive welding technical parameters.

[0029] (2) In this invention, the kinetic energy of the coating is used as the welding energy source for explosive welding. The impact velocity of the coating during explosive welding is determined according to the welding energy requirements. The welding energy and the kinetic energy of the coating are proportional. The range of values ​​for the collision angle θ is determined with reference to the fourth strength theory and the welding energy requirements.

[0030] (3) This invention proposes the concepts of lower limit and upper limit of welding energy, clarifies the energy range for explosive welding, and defines the explosive welding parameter V. c The -θ window provides a basis for its creation.

[0031] (4) The present invention determines the cladding impact velocity V based on measurable welding energy. p Then, based on the impact velocity V of the coating p Explosive detonation velocity V d The methods for determining the spacing between the base layer and the explosive based on the conservation of energy and the determination of the explosive thickness based on the conservation of momentum are more scientific than existing empirical formulas.

[0032] (5) Explosive welding was achieved by the method provided by the present invention, which verifies the feasibility of the method.

[0033] 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

[0034] 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.

[0035] Figure 1 This is a schematic diagram of the parallel explosive welding process of the present invention;

[0036] Figure 2 This is a schematic diagram of the stress state of the impact-resistant base layer of the present invention;

[0037] Figure 3 The explosive welding parameter V of the present invention c -θ window diagram;

[0038] Figure 4 This is a schematic longitudinal section diagram of the assembly of a planar component prepared by explosive welding according to Embodiment 1 of the present invention;

[0039] Figure 5 This is a cross-sectional view of the assembly of the cylindrical component prepared by explosive welding according to Embodiment 2 of the present invention;

[0040] Figure 6 This is an assembly diagram of the aluminum-copper composite laminar flow plate structure prepared by explosive welding in Embodiment 3 of the present invention.

[0041] In the diagram, V c V is the velocity at the point of collision. p V is the impact velocity of the coating, θ is the impact angle, and V d For maximum speed, Vp cos(θ / 2) is V p The longitudinal velocity component perpendicular to the base layer, V p sin(θ / 2) is V p The transverse velocity component parallel to the base layer, σ is the dynamic compressive normal stress between the overlay and the base layer, τ is the shear stress between the overlay and the base layer, and Ⅱ is the minimum impact angle θ. min Ⅳ is the maximum collision angle θ max Lines I and IV represent the minimum velocity V at the point of impact. cmin Lines II and III represent the maximum velocity V at the point of impact. cmax Lines I and II are the lower limit isoenergy lines for welding energy; lines III and IV are the upper limit isoenergy lines for welding energy; 1-substrate, 2-sealing plate, 3-covering plate, 4-supporting cover plate, 5-gasket mechanism, 6-explosive composition, 7-compression resistant material, 8-supporting container, 9-welding site foundation, 10-detonation system, 11-hollow channel, 12-base layer, 13-covering layer, 14-covering plate, 15-copper tube, 16-substrate, 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

[0042] The following detailed description of a method for designing explosive welding process parameters, with reference to specific embodiments, is provided. These embodiments are for comparison and explanation purposes only, and the present invention is not limited to these embodiments.

[0043] Metal welding is essentially a process in which two or more similar or dissimilar materials are joined together through the bonding and diffusion between atoms or molecules. The methods that induce this bonding and diffusion between atoms and molecules are heating or pressurizing, or both simultaneously. Therefore, the energy required for the bonding and diffusion between metal atoms and molecules during welding is called welding energy. Welding is the process by which the metal converts absorbed energy into welding energy. The total welding energy required depends on the properties of the same or different metals being welded, the weld area, the weld depth, and the weld strength. Whether welding can be achieved depends on the welding energy obtained by the metal per unit area and per unit time, called welding energy density. If the welding energy density obtained by the metal is lower than the minimum energy required for the bonding and diffusion between metal atoms and molecules—that is, if atoms and molecules cannot diffuse across the interface between the two metals—then welding cannot occur. Therefore, the minimum energy required for the bonding and diffusion between metal atoms and molecules is called the lower limit of the welding energy density of the same or two metals being welded. Similarly, if the welding energy density obtained by the metal is too high, the energy supply exceeds the objective needs for the bonding and diffusion between the metal atoms or molecules used for welding on a microscopic level. Macroscopically, this may manifest as a welding temperature far exceeding the melting point of one or both metals, resulting in energy waste or poor welding performance. Therefore, the highest energy required for bonding and diffusion between the metal atoms and molecules used for welding is called the upper limit of the welding energy density for the same or two metals being welded. Likewise, if the welding energy density is higher than the lower limit of the metal's welding energy density, but the excess is too small, it will take a very long time to complete the welding, resulting in low welding efficiency. This is also impractical. Similar impractical situations can occur near the upper limit of the welding energy density. Therefore, an appropriate welding energy density range must be selected between the lower and upper limits.

[0044] Another factor that determines the weld depth and weld strength is the welding time or welding speed. A determined weld depth and weld strength means a determined welding energy. The welding energy per unit weld area is the product of the welding energy density and the time. Therefore, theoretically, the design of welding process parameters is the combination of welding energy density and welding speed within the selectable welding energy density range.

[0045] Modern welding relies on a variety of energy sources, including fusion welding processes that depend solely on heat energy such as gas flame, electric arc, laser, and electron beam; cold pressure welding that depends solely on pressure; and explosive welding, friction welding, ultrasonic welding, and resistance welding that depend on both pressure and heat energy. In short, all these external pressures and / or heat energies must be converted into welding energy to be effective in welding.

[0046] Explosive welding is a welding process that is completed instantaneously within microseconds. It is also a welding process that involves both pressure and heat energy. Therefore, from an energy perspective, the kinetic energy of the cladding impacting the base layer is instantly converted into the plastic deformation energy of the base and cladding metals. 90-95% of the plastic deformation energy is then converted into heat energy. At the same time, pressure and heat energy are further converted into welding energy. And within a certain range of welding energy density and time required for welding to occur, this is the inherent meaning of explosive welding.

[0047] Therefore, based on energy conversion and energy balance, this invention proposes a method for designing explosive welding process parameters, including the following steps:

[0048] Step 1: Determine the base layer and cladding layer in explosive welding based on the unit area mass of the welding material, and set the base layer and cladding layer in parallel.

[0049] Step 2: Determine the impact velocity V during explosive welding based on the material parameters of the base layer and the coating layer. c The optional range;

[0050] Step 3: Based on the material parameters of the base layer and the cladding layer, determine the welding energy required for welding. Use the kinetic energy of the cladding layer as the welding energy source, and determine the impact velocity V of the cladding layer 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 and coating impact velocity V p The specific value;

[0051] Step 4: Based on the coating impact velocity V p Collision angle θ, explosive detonation velocity V d The physical parameters of the base layer and the explosive are used to determine the spacing A between the base layer and the base layer based on the conservation of function.

[0052] Step 5: Based on the coating impact velocity V p Explosive detonation velocity V d The physical parameters of the coating and explosive are used to determine the thickness ζ of the explosive charge based on the conservation of momentum.

[0053] It should be noted that the process parameters for explosive welding are divided into static parameters and dynamic parameters. Static parameters mainly include the properties and quantity of the explosive, the physicochemical and mechanical properties of the base layer and the cladding layer, the placement state between the base layer and the cladding layer, and the physical state of the buffer layer and the foundation, etc. Dynamic parameters include the bending angle, impact angle, impact velocity of the cladding layer, impact point velocity, and detonation velocity of the explosive, etc. However, once the explosive and the base and cladding layers are selected, the static parameters only refer to the quantity of explosive, i.e., the thickness of the explosive charge and the spacing between the base and the cladding layer. Moreover, once the static parameters are determined, the corresponding dynamic parameters are also determined accordingly. Therefore, the process parameters that need to be determined in this invention are the spacing between the base and the cladding layer and the thickness of the explosive charge. However, as mentioned above, the realization of explosive welding depends on these dynamic parameters. Therefore, it is necessary to use the dynamic parameters as basic data to deduce the static parameters. Designing appropriate dynamic parameters and establishing a scientific relationship between dynamic and static parameters is naturally the premise and condition for determining the static parameters. Ultimately, the effect and quality of explosive welding depend on whether the determination of the static parameters is reasonable.

[0054] Currently, typical explosive welding processes include welding of flat plates with parallel upper and lower layers and welding of circular tubes with parallel inner and outer layers. Specifically, in step 1, a flat plate or circular tube with a smaller unit area mass is selected as the cladding layer in explosive welding, and a flat plate or circular tube with a larger unit area mass is selected as the base layer. When the unit area mass of the flat plate or circular tube is equal, either one can be selected as the cladding layer or the base layer in explosive welding.

[0055] It should be noted that in steps 2 and 3, the welding energy originates from the impact kinetic energy of the cladding layer. That is, a portion of the impact kinetic energy of the cladding layer is converted into the welding energy required for welding. The impact kinetic energy of the cladding layer, in turn, originates from the work done by the explosive explosion on the cladding layer. Although explosive welding is very fast, it is still a process in which the interface caused by the collision between the cladding layer and the base layer gradually advances in a wave-like pattern. The formation of the collision interface wave originates from the ZND theory of explosive detonation. The ZND theory of explosive detonation posits that the explosion process is a process of continuous superposition of several explosion reaction zones along the explosion direction. The detonation wave and the pressure of the explosion products in each reaction zone do work outward according to a certain wave-like pattern. If the cladding layer is considered to be composed of countless particles, then each particle experiences different pressures due to the influence of the wave-like pattern of the explosion reaction, resulting in different velocities and different impact pressures on the base layer. This leads to the formation of a wave-like bond at the base-cladding interface. The width of the detonation wave reaction zone is determined by the properties of the explosive itself, ranging from 0.1 to 1.0 mm. The wavelength of the interface wave between the cladding layer and the base layer also falls within this range.

[0056] If we divide the trough and two crests of the interface wave between the base and cladding layers into a period, the trough, also known as the collision point, is the stationary point of the collision and is caused by the particle with the highest kinetic energy in the cladding layer, while the crest is caused by the particle with the lowest kinetic energy in the cladding layer. If we use one collision point to represent one period of the interface wave, then explosive welding is a continuous welding process that follows the movement of the collision point. The sum of the energy of welding at countless collision points is the welding energy of the entire weld. Under uniform flux distribution, we can approximate the welding energy at each collision point as equal, that is, the welding energy of each period of the interface wave is considered equal. This is equivalent to the welding energy per unit area and per unit time mentioned earlier, i.e., the welding energy density mentioned earlier. The wavelength of the interface wave determines the unit area of ​​the welding energy density, and the period of the interface wave is the unit time of the welding energy density. Due to the instantaneous nature of explosive welding, the unit time corresponding to the welding energy density is the welding time. Therefore, the welding energy density is the welding energy at each collision point. The weld layer between the base and cladding extends along the path of the interface wave. The wave height of the interface wave represents the thickness of the weld layer. However, within each collision point, i.e. within one wavelength range of the interface wave, the welding energy on the weld layer is not equal everywhere. Instead, it is periodically distributed along the wavelength and wave height directions according to certain rules based on the physicochemical and mechanical properties of the base and cladding materials. For example, the welding energy is relatively high in the wave crests and troughs. Therefore, the welding energy within a collision point, i.e. within one cycle of the interface wave, is the sum of the welding energies of all points in the weld layer. It is conceivable that the distribution law of welding energy along the interface can be written in the form of a Fourier series wave function.

[0057] Furthermore, practice has proven that a well-developed base-cladding wave interface in explosive welding is usually a prerequisite for achieving high weld strength. The wave interface increases the area of ​​the welding surface between the base and cladding, providing favorable conditions for the conversion of cladding kinetic energy into welding energy. Studies show that the total welding energy within the weld layer is positively correlated with wave height and wavelength. When both wave height and wavelength are small, the total welding energy is low; when both wave height and wavelength are large, the total welding energy is high. As mentioned earlier, welding strength is positively correlated with welding energy. Maintaining uniform and stable welding energy in the weld layer means that the weld layer is composed of a stable and regular wave-like morphology. Therefore, it is necessary to control the wavelength and wave height of the interface wave within a certain range. The sole external cause of the waveform interface between the base and cladding layers in explosive welding is the explosive detonation, which is also the prerequisite and condition for the generation of interface waves. After selecting the explosive, the detonation velocity is directly related to the explosive detonation among the dynamic parameters of explosive welding. The detonation velocity is positively correlated with the impact point velocity. When the base and cladding layers are set in parallel, the detonation velocity equals the impact point velocity, i.e., the welding speed. The cladding impact velocity is also positively correlated with the impact point velocity; that is, the explosive detonation velocity determines the cladding impact velocity and the welding speed. The internal cause of the waveform interface between the base and cladding layers in explosive welding is related to the properties of the base and cladding metal materials, such as strength and density. Studies show that for a given base and cladding metal material, the complete wave shape will only be clearly exhibited when the explosive detonation velocity reaches a certain value. Therefore, achieving welding necessarily requires the welding speed to reach a certain critical value, which is the impact point velocity V. c Minimum value V cmin .

[0058] However, when the velocity at the point of impact exceeds the speed of sound in the material, a strong compressive wave phenomenon similar to a shock wave is generated. This causes abrupt and discontinuous changes in the material's physical properties such as pressure, temperature, and density, causing the welding material to deviate from a stable and uniform physical and mechanical state, thus affecting the welding process. Therefore, the speed of sound in the material is taken as the velocity at the point of impact, V. c The maximum value V cmax .

[0059] Specifically, in step 2, the velocity V at the collision point is determined. c Optional range:

[0060] 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 HV represents the Vickers hardness of the coating, measured in Pascals (HV).b ρ is the Vickers hardness of the substrate, measured in Pascals; f ρ is the density of the coating, expressed in kilograms per cubic meter. b The density of the base layer is expressed in kilograms per cubic meter. The velocity at the point of impact, V. c The maximum value V cmax This is the minimum sound velocity of the overlay and the base layer, expressed in meters per second.

[0061] Furthermore, the welding energy originates from the impact kinetic energy of the cladding layer. This impact kinetic energy is provided by two parts of energy from the explosion reaction: most of it comes from the detonation wave pressure generated during the explosion reaction, and a small part comes from the pressure of the explosion reaction products. The propagation speed of the detonation wave is (γ+1) times the propagation speed of the explosion products, where γ is the adiabatic index of the explosion products. For condensed explosives, γ is generally 3. Due to the conservation of mass before and after the chemical reaction, the energy of the detonation wave is (γ+1) times the energy of the explosion products. 2 The impact of the base layer and cladding layer is converted into plastic deformation energy at the bonding interface. 90-95% of this plastic deformation energy is then converted into heat energy, and the remaining small portion of plastic deformation energy is stored inside the deformed material as distortion energy; this portion of energy is called stored energy. After the base and cladding layer impact bonding, some of the remaining energy from the detonation wave and explosion products is converted into pressure after the base and cladding layer bonding. Then, the heat energy converted from plastic deformation energy and the pressure are combined and further converted into welding energy. As mentioned earlier regarding the waveform distribution of the welding interface, the energy ratio of the combined heat energy and pressure also exhibits a wave-like pattern. Therefore, explosive welding is a welding method that combines fusion welding, pressure welding, and diffusion welding.

[0062] Specifically, in step 3, the welding energy is directly proportional to the kinetic energy of the cladding layer, and the lower limit of the welding energy is related to the impact velocity V of the cladding layer. p Minimum value V pmin The following conditions must be met:

[0063] (1 / 2MV pmin 2 )η=E wmin =σ b SH f In equation (2), M is the cladding mass in kilograms, and M = SH f ρ f S represents the area of ​​the cladding layer, in square meters, which is generally the welding area; ρ f H represents the density of the coating, expressed in kilograms per cubic meter. f V represents the coating thickness, in meters. pmin This represents the minimum impact velocity of the coating, expressed in meters per second; 1 / 2MV pmin 2E represents the minimum kinetic energy of the cladding impact, measured in joules; η is the conversion rate of the cladding impact kinetic energy into welding energy. wmin The lower limit of welding energy is expressed in joules; σ b The tensile strength of the cladding or base material is expressed in Pascals; S is the weld area, which is generally the area of ​​the cladding; 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, expressed as a percentage, dimensionless, and generally falling between the elongation of the cladding layer and the base layer. 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, 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.

[0064] Specifically, when the materials of the cladding and the base layer are the same, the standard welding strength required for welding is the tensile strength of that material, and the welding energy is the minimum fracture energy of the weld layer. As can be seen from equation (2), the impact velocity V of the cladding is... p Minimum value V pmin =2σ b βδ / (ηρ 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 means that within the microsecond range of explosive welding, the conversion rate η of the cladding impact kinetic energy into welding energy is related to the material elongation δ. That is, a higher material elongation results in a higher conversion rate, and a lower material elongation results in a lower conversion rate. At this point, the conversion rate η is approximately equal to 2βδ, therefore: V pmin =(σ b / ρ f ) 1 / 2 (3).

[0065] When the base material and cladding material are different, the standard weld strength required is generally the average of the tensile strengths of the base material and cladding material. However, due to differences in the physicochemical properties of dissimilar metals, welding dissimilar metals is usually more difficult than welding homologous metals. Moreover, besides the influence of their own physicochemical properties on weldability, the differences in their material properties have a greater impact, such as differences in melting point, coefficient of linear expansion, thermal conductivity, and specific heat. The greater the difference, the more difficult the welding. On the other hand, the crystallization chemical properties between dissimilar metals are also important factors affecting weldability, such as unlimited solid solution, limited solid solution, intermetallic compounds, and immiscibility. Therefore, research on dissimilar metal welding should be conducted on a case-by-case basis. However, the energy consumed in welding dissimilar metals or homogeneous metals is the same. The only difference lies in the amount of energy consumed and how much of that energy actually contributes to strengthening the bond between the dissimilar metals. For example, some energy may contribute to the connection, but the bonding strength is weak, such as in intermetallic compounds. Furthermore, these effective, ineffective, and even negatively effective energy expenditures occur simultaneously during welding, making separation difficult. Therefore, the actual energy consumed in welding dissimilar metals should be the sum of all these factors, with the true welding energy being only a portion. Of course, the welding energy of dissimilar metals can also be assessed using fracture energy. However, if the standard welding strength is the average of the tensile strengths of the base layer and cladding, it clearly does not represent the actual energy consumed in welding dissimilar metals. That is, the actual energy consumed in welding dissimilar metals is greater than the true welding energy and fracture energy. Therefore, the higher tensile strength of the base layer and cladding materials is used to calculate the minimum welding energy, which is the minimum impact velocity for welding the cladding to dissimilar metals.

[0066] V pmin =(σ b1 / ρ f ) 1 / 2 (4)

[0067] In equation (4), σ b1 It has the highest tensile strength among base and coating materials.

[0068] It should be noted that the heat energy required for welding comes from plastic deformation energy. The occurrence of plastic deformation first requires the base and cladding to yield under the impact of the cladding. Plastic deformation occurs within the microsecond range of explosive welding. The dynamic yield strength under such high strain rate is much higher than the static yield strength of the material. Depending on the specific mechanical properties of the base and cladding materials, the dynamic yield strength is 1 to 3 orders of magnitude higher than the static yield strength.

[0069] Figure 1 This is a schematic diagram of the parallel explosive welding process of the present invention. Figure 1The intermediate cladding layer 13 impacts the cladding layer 12 at an angle θ. In the dynamic parameters of explosive welding, angle θ is called the impact angle, measured in degrees. When arranged in parallel, the explosive detonation velocity V... d and the velocity V at the point of collision c Equal, the velocity V at the point of collision c and coating impact velocity V p There is a V between them p =2V c sin(θ / 2), since the collision angle θ is small, we have 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 coating pmin Therefore, the minimum collision angle θ is obtained. min =arcsin(V pmin / V cmax The impact velocity V of the coating p Orthogonally decomposed into longitudinal velocity component V perpendicular to the base layer p cos(θ / 2) and the lateral velocity component V parallel to the base layer p sin(θ / 2), according to the principle of conservation of momentum, the dynamic compressive normal stress σ between the overcoat and the base layer and the longitudinal component of the overcoat impact velocity perpendicular to the base layer V p cos(θ / 2) is directly proportional to the shear stress τ between the overcoat and the base layer, and the impact velocity of the overcoat is parallel to the transverse component V of the base layer. p It is directly proportional to sin(θ / 2) Figure 2 This is a schematic diagram of the stress state of the impact-resistant base layer of the present invention.

[0070] For the yielding phenomenon of materials under dynamic impact compression, the fourth strength theory of materials in static conditions can be referred to. When the distortion energy density of the kinetic energy converted from the impact of the coating exceeds the material's limit value (1+ν)σ, S 2 At / 3E, the material undergoes plastic yielding, where ν is the Burson-Stokes ratio and σ is the tensile strength. S Let E be the dynamic yield strength and E be the elastic modulus. Since welding energy is derived from plastic deformation energy, the minimum welding energy corresponds to the critical distortion energy at which yielding occurs. Therefore, the minimum impact velocity V corresponding to reaching the lower limit of welding energy is... pmin It is also the minimum impact velocity V of the coating material when the base and coating materials yield. pmin Similarly, referring to the stress failure criterion of the fourth strength theory: (σ 2 +3τ 2 ) 1 / 2 ≥σ S , where (σ 2+3τ 2 ) 1 / 2 For dynamic compression equivalent stress, σ S For the larger dynamic yield strength in the overcoat and base course, calculations show that when V p (2-cosθ) 1 / 2 ≥V pmin (2-cosθ min ) 1 / 2 At that time, the dynamic compressive equivalent stress reached or exceeded the larger dynamic yield strength σ in the overlay and base layer. S Plastic deformation occurs. Furthermore, let 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.

[0071] Furthermore, as the impact velocity of the coating increases, the dynamic yield strength of the material also increases. However, when the impact velocity exceeds a certain range, the internal temperature of the material gradually rises with the increase of plastic deformation. When the softening effect, such as temperature rise, exceeds the hardening effect, such as strain and strain rate, the dynamic yield strength of the material begins to decrease, leading to deformation instability and the formation of an adiabatic shear band. Severe adiabatic shear phenomena can cause material failure. Therefore, the dynamic yield strength at which adiabatic shear failure begins to occur is taken as the maximum dynamic compressive equivalent stress of explosive welding. Studies have shown that the dynamic yield strength at which adiabatic shear failure occurs is positively correlated with the material's ability to absorb plastic deformation energy and fracture work under impact load, i.e., the impact work Ak. The greater the impact work, the greater the dynamic yield strength; the smaller the impact work, the smaller the dynamic yield strength.

[0072] Furthermore, if localized heat accumulation occurs in the material before adiabatic shear failure, causing the welding energy at certain points on the weld layer to exceed the upper limit of the required welding energy density, metal overmelting will occur. For welding of the same metal, appropriate overmelting has a relatively small impact on weld quality. However, for welding of dissimilar metals, overmelting can easily generate harmful intermetallic compounds, reducing weld strength. Therefore, the dynamic compressive equivalent stress when metal overmelting occurs is also considered as the maximum dynamic compressive equivalent stress in explosive welding.

[0073] In summary, due to the differences in the physicochemical and mechanical properties of metallic materials, the maximum dynamic compressive equivalent stress in explosive welding varies depending on the base and cladding materials. Therefore, based on the specific actual conditions, the maximum dynamic compressive equivalent stress in explosive welding is generally related to the dynamic yield strength σ corresponding to the lower limit of the welding energy. S The value is taken from a relatively high range, and the highest value of the dynamic compressive equivalent stress caused by the impact of the cladding is set as the dynamic yield strength σ corresponding to the lower limit of the welding energy. S The value is k times the value of the maximum dynamic compressive equivalent stress, where k is a number between 2 and 4, such as 3. The corresponding welding energy obtained under the maximum dynamic compressive equivalent stress is the upper limit of the welding energy E. wmax .

[0074] Similarly, set V c sinθ(2-cosθ) 1 / 2 =kV pmin (2-cosθ min ) 1 / 2 V can be obtained c The correspondence between V and θ yields a V that represents the upper limit of welding energy. c The 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.

[0075] Figure 3 The explosive welding parameter V of the present invention c -θ window diagram. In the figure, II represents the minimum collision angle θ. min Ⅳ is the maximum collision angle θ max Lines I and IV represent the minimum velocity V at the point of impact. cmin Lines II and III represent the maximum velocity V at the point of impact. cmax Lines I and II are the lower limit isoenergy lines for welding energy; lines III and IV are the upper limit isoenergy lines for welding energy. The I, II, III, and IV windows represent the optional explosive welding V. c -θ parameter range.

[0076] Furthermore, determine the specific value of the collision angle θ:

[0077] Collision angle θ = θ min +n(θ max -θ min (5), where n is an adjustment coefficient, which is a number between 0 and 1, such as 0.5.

[0078] It should be noted that the typical collision angle θ ranges from 3° to 30°.

[0079] Furthermore, based on the already determined specific value of the collision angle θ, the explosive welding parameters V... cThe velocity V at the collision point is determined within the -θ window. c The specific value.

[0080] Specifically, in the explosive welding parameter V c The collision angle θ corresponding to point I is calculated on the isoenergetic line of the lower limit of the welding energy in the -θ window. Ⅰ On the isoenergy line of the upper limit of welding energy, the collision angle θ corresponding to point III is calculated. Ⅲ .

[0081] (1) If θ≤θ Ⅰ And θ≤θ Ⅲ :

[0082] First, according to the formula: V c1 sinθ(2-cosθ) 1 / 2 ) = V pmin (2-cosθ min ) 1 / 2 Find the velocity V at the point of collision. c1 Then, according to the formula: V c =V c1 +y(V cmax -V c1 (6) Calculate the velocity V at the collision point. c ;

[0083] (2) If θ Ⅲ ≤θ≤θ Ⅰ :

[0084] First, according to the formula: V c1 sinθ(2-cosθ) 1 / 2 =V pmin (2-cosθ min ) 1 / 2 Find the velocity V at the point of collision. c1 Then, according to the formula: V c2 sinθ(2-cosθ) 1 / 2 =kV pmin (2-cosθ min ) 1 / 2 Find the velocity V at the point of collision. c2 Finally, according to the formula: V c =V c1 +y(V c2 -V c1 (7) Calculate the velocity V at the collision point. c ;

[0085] (3) If θ Ⅰ ≤θ≤θ Ⅲ :

[0086] According to the formula: V c =Vcmin +y(V cmax -V cmin (8) , calculate the velocity V at the collision point. c ;

[0087] (4) If θ Ⅰ ≤θ, and θ Ⅲ ≤θ:

[0088] First, according to the formula: V c2 sinθ(2-cosθ) 1 / 2 =kV pmin (2-cosθ min ) 1 / 2 Find the velocity V at the point of collision. c2 Then, according to the formula: V c =V cmin +y(V c2 -V cmin (9) Calculate the velocity V at the collision point. c ;

[0089] In equations (6), (7), (8), and (9) above, y is an adjustment coefficient, which is a number between 0 and 1, such as 0.5.

[0090] 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 coating is obtained p .

[0091] It should be noted that in steps 4 and 5, the existing technology uses a method that correlates the base, cladding spacing, and explosive thickness for calculation, employing the Gryllium energy balance calculation method. Gryllium energy calculation originated in military applications and is a method for calculating the initial velocity of fragments. A key concern of Gryllium energy calculation is how to most effectively convert the energy released during explosive detonation into the kinetic energy of the metal within a sealed metal casing. However, the reality of explosive welding differs significantly. Explosive welding involves laying explosives flat on the cladding surface in a relatively open environment. The explosive detonation wave front is perpendicular to the cladding surface, i.e., the detonation wave slips during incidence. This differs from the actual situation in Gryllium energy calculation, and the Gryllium energy of the explosive is an unknown constant, making it unsuitable for practical technical parameter design. Therefore, the inventors calculated the base, cladding spacing, and explosive thickness separately. In the calculation of the base and cladding spacing, the existing calculation method was simplified to a function conservation calculation method. For calculating the thickness of the explosive charge, since a large amount of heat is released during the explosion, firstly, the heat of explosion cannot be calculated accurately, and secondly, the work done on the cladding layer by the sliding incident explosive wave is limited to one side, and the explosive energy in other directions cannot be statistically calculated. Therefore, it is not suitable to use energy conservation to calculate it. Instead, a momentum conservation calculation method is adopted according to the area distribution of the explosive explosion.

[0092] Specifically, in step 4, the formula for conservation of function is:

[0093] P C-J k0SA / cos(θ / 2)=1 / 2MV p 2 (10)

[0094] In equation (10), P C-J V is the pressure on the wavefront CJ of the explosive detonation wave, in Pascals; k0 is the pressure adjustment coefficient, ranging from 0.6 to 0.7; S is the cladding area, in square meters; A is the distance between the base layer and the cladding layer, in meters; θ is the impact angle, in degrees; M is the cladding mass, in kilograms; V p The value represents the impact velocity of the coating, measured in meters per second.

[0095] Specifically, P C-J =ρ0V d 2 / (γ+1)(11)

[0096] In equation (11), ρ0 is the density of the explosive, 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.

[0097]

[0098] For condensed explosives, the general value is 3,c. p c is the isobaric heat capacity of the explosion products. v Let c be the isochoric heat capacity of the explosion products. When the explosion products are considered as ideal gases, c p / c v =1.25; n i γ is the amount of substance (mol) of component i in the explosion products. i Let V be the adiabatic index of component i in the explosion products. It should be noted that when the base layer and cladding layer are arranged in parallel, the explosive detonation velocity V... d and the velocity V at the point of collision c 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 .

[0099] It should be noted that in this invention, the explosive ramming pressure is approximated as the pressure on the detonation wave front CJ as the average pressure of the detonation wave, because detonation theory believes that the pressure on the detonation wave front CJ is the pressure expression when the explosion state is stable.

[0100] Furthermore, when explosives are laid flat on the cladding layer and the detonation wave moves parallel to the cladding surface, the wavefront of the detonation wave is perpendicular to the cladding surface, i.e., the incident angle is 90°. After impacting the cladding, the detonation wave is reflected back as an expansion wave; this phenomenon is called Prandtl-Mayer expansion. The calculation of the cladding surface pressure in the Prandtl-Mayer expansion zone is related to the impact compression characteristics of the cladding metal. The impact compression curve reflects the relationship between pressure, density, wave velocity, particle velocity, and specific internal energy of a substance under high-speed impact and high pressure. Compared with industrial explosions, the detonation velocity and detonation pressure of explosive welding are relatively low. In addition, the adiabatic index γ of the explosion products is also a decisive factor affecting the cladding surface pressure. Summarizing existing data, under slip detonation, the pressure of the cladding is less than the pressure on the detonation wavefront CJ, approximately P. C-J The pressure adjustment coefficient k0 is 0.6 to 0.7 times that of the pressure adjustment coefficient, i.e., the pressure adjustment coefficient k0 is 0.6 to 0.7.

[0101] Specifically, in step 5, the formula for the conservation of momentum is ΓζSρ0V. d =MV p In equation (12), ζ is the thickness of the explosive charge in meters; S is the area of ​​the coating in square meters; ρ0 is the density of the explosive in kilograms per cubic meter; V d V is the detonation velocity of the explosive, measured in meters per second; M is the cladding mass, measured in kilograms; V pΓ represents the impact velocity of the cladding layer, measured in meters per second; Γ is the ratio of the momentum of the explosive acting in the direction of the cladding layer to the total momentum of the explosive.

[0102] It should be noted that the charge thickness ζ calculated in this invention refers to the charge thickness that reaches or exceeds the stable detonation zone, that is, the charge thickness is greater than the critical thickness of the explosive, and the detonation velocity V is within the stable detonation zone. d It can propagate at a constant speed.

[0103] Specifically, the cladding layer is N meters long and μ meters wide, N≥μ, S=Nμ, the detonation direction is along the length direction, and a section with the same cladding width and explosive thickness ζ is taken for calculation, that is, the cross-sectional area of ​​the explosive is ζ×ζ, the length is N (N equals the length of the web), and satisfies N≥2.25ζ.

[0104] According to the principle of conservation of momentum, we have the following equation:

[0105]

[0106] It can be seen that Г is:

[0107]

[0108] In equation (13), γ is the adiabatic index of the explosion products, which is generally 3 for condensed explosives. Substituting equation (13) into equation (12), we can obtain the thickness ζ of the explosive charge.

[0109] It should be noted that the above calculation data comes from the impulse received by the rigid wall of the charge end under the conditions of absolutely rigid cylindrical charge and shell-less cylindrical charge in the existing technology. Then, according to the principle of conservation of momentum, it is simplified to four directions in a two-dimensional state, that is, the resultant momentum of the four directions is zero overall, and the resultant momentum of the opposite pair of directions is zero. Assuming that the sidewall of the semicircular tube is rigidly constrained, the overall impulse of the sidewall of the semicircular tube is obtained after data comparison and processing.

[0110] In this invention, a portion with equal cladding width and charge thickness ζ is used for calculation. The explosive shape is a cube with two opposite square faces, which is fitted to the cylindrical charge in the prior art. The side length of the square is equal to the diameter of the cylinder. In comparison, the charge of the cube is 27% more than that of the cylinder. Furthermore, the impulse in the prior art is for an incompressible, absolutely rigid body, while the actual cladding is a compressible metal. The compressibility of different materials reduces the impulse by 5-20% compared to an absolutely rigid body. Moreover, there is no constraint on the two explosive end faces of the long side of the cladding in this invention, unlike the cylindrical charge. However, this is limited to the sparseness on the two end faces, and the sparseness does not exist in the interior between the two end faces. The impulse reduced by these two parts is precisely compensated by the aforementioned extra 27% charge.

[0111] 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.

[0112] Example 1

[0113] In this embodiment, a planar component with complex hollow channels is prepared by explosive welding of composite materials. Figure 4 This is a longitudinal sectional view of the explosive welding assembly. Specifically, the complex hollow channel substrate 1 is a steel block with a rectangular groove, the plate size is 300mm×200mm×40mm, and the groove machined in the middle is 300mm×20mm×20mm and machined in the middle of the plate; the rectangular groove sealing plate 2 is made of the same steel as the substrate 1, the shape is a rectangular plate, the size is 300mm×20mm×10mm; the cover plate 3 is a copper plate with high thermal conductivity, the size is 280mm×180mm×1mm; the supporting cover plate 4 is an aluminum plate with a thickness of 350mm×250mm×1mm; the explosive composition 6 is a sensitized industrial explosive welding explosive.

[0114] A composite welding method for composite materials with complex hollow channels includes the following steps:

[0115] Step T1: Electron beam welding process with the following parameters: accelerating voltage 140kV, scanning shape O-type, and vacuum pressure less than 5×10⁻⁶. -2 Pa, the rectangular groove on the substrate 1 is welded together with the rectangular groove sealing plate 2 to form a complex hollow channel 11 with circumferential metallurgical sealing, and at the same time, it is combined to form the base layer 12.

[0116] Step T2: Process the welding surface of the base layer 12 into a smooth surface with no oxide layer and a roughness of less than 3 micrometers, and clean the inner surface.

[0117] Step T3: Place the support container 8 on the welding site foundation 9. Fill the support container 8 with anti-compression material 7—water. Then immerse the base layer 12 in the support container 8 so that the water fills the hollow channel 11, but the welding surface of the base layer 12 is not submerged in the water and is exposed to the outside.

[0118] Step T4: Set a cover plate 3 opposite to the welding surface of the base layer 12, and glue a support cover plate 4 to the back of the welding surface of the cover plate 3. The periphery of the support cover plate 4 extends beyond the periphery of the cover plate 3. Set a gasket mechanism 5 at the part of the support cover plate 4 that extends beyond the periphery of the cover plate 3. The gasket mechanism 5 uses aluminum washers, is placed on the complex hollow structure base 1, and is located at the edge of the material. The gasket mechanism 5 is used to support the cover plate 3 and the support cover plate 4, so that there are no obstacles between the cover plate 3 and the base layer 12, and the two maintain a basically uniform interval distance.

[0119] Step T5: Arrange the explosive composition 6 on the outer surface of the support cover plate 4;

[0120] Step T6: Detonation is controlled by detonation system 10 connected to explosive composition 6. The explosion proceeds along the groove direction to achieve explosive welding of base layer 12 and cover plate 3.

[0121] Step T7: After welding, the water has been drained from the cavity. The excess part of the complex hollow structure material after explosive welding is cut off and processed to the required size by machining and polishing.

[0122] Specifically, the explosive welding process is determined according to the following steps:

[0123] Step 1: A steel block with a rectangular groove and a rectangular groove sealing plate are combined to form a base layer, and a copper plate is used as a cover plate, i.e., a cladding layer. The base layer and the cover plate are set in parallel.

[0124] Step 2: Determine the impact velocity V during explosive welding based on the material parameters of the base steel block and the copper cladding plate. c The optional range;

[0125] Collision point velocity V c Minimum value V cmin =(2R) e (H f +H b ) / (ρ f +ρ b )) 1 / 2 = (2×10.6×(0.833×10)) 9 +3.136×10 9 ) / (8900+7800)) 1 / 2 = 2245 (m / s);

[0126] Collision point velocity V c The maximum value V cmax It is 4700 meters per second.

[0127] Step 3: Based on the material parameters of the base steel block and the cladding copper plate, determine the welding energy required for welding. Use the cladding kinetic energy as the welding energy source, and determine the cladding impact velocity V 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 and coating impact velocity V p The specific value;

[0128] Determine the impact velocity V of the cover plate p The minimum values ​​are: V pmin =(σ b1 / ρ f )1 / 2 = (1.03 × 10 9 / 8900) 1 / 2 = 340 m / s;

[0129] Minimum collision angle θ min =arcsin(340 / 4700)=4.15°;

[0130] The maximum value of the dynamic compressive equivalent stress caused by the cladding impact is set as the dynamic yield strength σ corresponding to the lower limit of the welding energy. S 3 times, maximum collision angle θ max =25.7°;

[0131] θ Ⅰ = 8.7°, θ Ⅲ =12.4°

[0132] Determine the specific value of the collision angle θ:

[0133] The collision angle θ = 4.15° + 0.3 × (25.7° - 4.15°) = 10.6°.

[0134] Due to θ Ⅰ ≤θ≤θ Ⅲ According to the formula: V c =2245 + 0.226 × (4700 - 2245) = 2800 m / s.

[0135] Impact velocity of the cover plate V p =V c sinθ=2800×sin10.6°=515 meters / second;

[0136] Step 4: Based on the impact velocity V of the copper-clad plate p Collision angle θ, detonation velocity V of the explosive composition d The physical parameters of the copper plate and the explosive composition are used to determine the spacing A between the base steel block and the copper plate in parallel arrangement based on the conservation of function.

[0137] According to formula 1 / 2MV p 2 Calculate the kinetic energy E of the cover plate when it is dropped. k = 59490 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 2800 m / s, k0 is taken as 0.60, γ = 2.5, and the explosion pressure P on the cladding plate is P = P C-J k0S=ρ0V d 2 / (γ+1)k0S=800×2800×2800×0.6×0.0504 / 3.5=5.419×10 7 Newton, according to the formula P C-J k0SA / cos(θ / 2)=1 / 2MV p 2 The calculation shows that the spacing between the base and the cover plates is A = 0.001 meters.

[0138] Step 5: Based on the impact velocity V of the copper-clad plate p Explosive composition detonation velocity V d The physical parameters of the copper cladding plate and the explosive composition are used to determine the explosive thickness ζ based on the conservation of momentum.

[0139] The formula for conservation of momentum is ΓζSρ0V d =MV p , The result shows that ζ = 0.007 meters, which means the thickness of the medicine application is 7 millimeters.

[0140] Example 2

[0141] Figure 5 This is a cross-sectional view of the assembly of a cylindrical component prepared by explosive welding according to Embodiment 2 of the present invention.

[0142] The complex hollow channel substrate 1 is made of a copper rod with a length of 200mm and an outer radius R2 of 25mm. A serpentine rectangular groove with dimensions of 250mm in length × 10mm in width × 10mm in depth is machined on the surface of the copper rod using a milling machine. The rectangular groove sealing plate 2 is made of the same material as the substrate 1 and is 1mm thick. The cover plate 3 is made of a copper plate with a length of 200mm and an inner radius R2 of 25mm. 20 27mm, outer radius R 10 The aluminum tube is 29mm thick; the support cover plate 4 is a 0.5mm thick aluminum plate; the explosive composition 6 is a sensitized industrial explosive welding explosive.

[0143] A welding method for cylindrical composite materials with complex hollow channels includes the following steps:

[0144] Step 1: Using laser welding fusion welding process, the hollow channel groove on the outer surface of the cylindrical substrate 1 is sealed with a hollow channel groove sealing plate 2. The laser welding power is 1500W. A complex hollow channel 11 with circumferential metallurgical sealing is formed by flat-head butt welding, and at the same time, it is combined to form the base layer 12.

[0145] Step 2: Grind the welding surface of the base layer 12 with a grinding wheel to obtain a smooth surface with a roughness of less than 3 micrometers and no oxide layer.

[0146] Step 3: Fill the hollow channel 11 with the anti-compression material 7—the water matrix 1, with the end face of the cylinder facing upwards, and place it on the welding site foundation 9;

[0147] Step 4: Cover plate 3 is a cylindrical tube wrapped around the cylindrical body 1. The inner surface of the cylindrical tube and the base 12 are opposite welding surfaces. Support cover plate 4 is a cylindrical tube glued to the outer surface of the cylindrical tube. In the axial length, the support cover plate 4 extends beyond the cylindrical tube. Four gasket mechanisms 5 are evenly arranged in the circumference of the support cover plate 4 extending beyond the cylindrical tube. The gasket mechanism 5 is an aluminum washer. One end of the gasket mechanism 5 is placed on the non-welded surface of the base 12, and the other end is placed on the inner surface of the support cover plate 4 extending beyond the cylindrical tube. The gasket mechanism 5 is used to support the cylindrical tube 3 and the support cover plate 4, so that there are no obstacles between the cylindrical tube 3 and the base 12, and the two maintain a basically uniform interval distance.

[0148] Step 5: Arrange the explosive composition 6 on the outer surface of the support cover plate 4;

[0149] Step 6: Detonation is controlled by detonation system 10 connected to explosive composition 6. The explosion proceeds along the axial direction of the pipe to achieve explosive welding of base layer 12 and cover plate 3.

[0150] Step 7: After welding, drain the water from the hollow channel 11 and process the material so that the outer contour of the material after explosive welding conforms to the required contour.

[0151] Specifically, the explosive welding process is determined according to the following steps:

[0152] Step I: Set the cover plate 3 and the base layer 12 in parallel, with the spacing between the base layer and the cover plate A = R. 20 -R2=2mm;

[0153] Step II: Determine the impact velocity V during explosive welding based on the material parameters of the base layer 12 and the cover plate 3. c The optional range;

[0154] Collision point velocity V c Minimum value V cmin =(2R) e (HV f +HV b ) / (ρ f +ρ b )) 1 / 2 = (2×10.6×(0.294×10)) 9 +0.833×10 9 ) / (2700+8900)) 1 / 2 =1435 (m / s);

[0155] Collision point velocity V c The maximum value V cmax It is 4700 meters per second;

[0156] Step III: Based on the material parameters of the base layer 12 and the cover plate 3, determine the welding energy required for welding. Use the kinetic energy of the cover plate as the welding energy source, and determine the impact velocity V of the cover plate 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 specific value of the collision angle θ is determined.

[0157] Determine the impact velocity V of the cover plate p The minimum values ​​are: V pmin =(σ b1 / ρ f ) 1 / 2 = (3×10 8 / 2700) 1 / 2 = 333 m / s;

[0158] Minimum collision angle θ min =arcsin(333 / 4700) = 4.06°

[0159] The maximum value of the dynamic compressive equivalent stress caused by the cladding impact is set as the dynamic yield strength σ corresponding to the lower limit of the welding energy. S 3 times, maximum collision angle θ max =39.06°

[0160] θ Ⅰ =13.26°, θ Ⅲ =12.15°

[0161] Determine the specific value of the collision angle θ:

[0162] The collision angle θ = 4.06° + 0.17 × (39.06° - 4.06°) = 10°.

[0163] Step IV: Based on the principle of conservation of energy, and according to the specific value of the collision angle θ, the distance A between the base layer and the cover plate, and the impact velocity V of the cover plate. p , velocity V at the point of collision c And explosive composition 6 detonation velocity V d The relationship between the three, as well as the physical parameters of the cladding plate 3 and the explosive composition 6, determines the impact velocity V of the cladding plate. p , velocity V at the point of collision c And the detonation velocity V of the explosive composition d The specific value;

[0164] Specifically, according to the formula: P C-J =ρ0V d 2 / (γ+1),

[0165] After performing equilibrium calculations, the dynamic yield strength Y0 of the aluminum tube with cladding plate 3 was set to 500 MPa, the detonation wave pressure adjustment coefficient k0 was set to 0.7, and the detonation velocity, explosive density, and adiabatic index γ of the explosion products were adjusted by adding industrial salt to the explosive composition 6. Finally, the impact velocity V of the cladding plate was obtained. p =500 m / s, the kinetic energy of the cladding plate 3 is 23738 joules, the deformation work of the circular tube of the cladding plate 3 against the circumferential resistance is 83184 joules, and 15% by mass of industrial salt is added to the explosive composition 6 to adjust the detonation velocity V. d The speed is 2860 m / s, and the velocity at the point of impact is V. c =V d =2860 m / s, explosive density is 900 kg / m³, and the thermal index γ of the explosion products is 2.5.

[0166] Step V: Based on the impact velocity V of the cover plate p Explosive composition 6 detonation velocity V d Based on the physical parameters of the covering plate 3 and the explosive composition 6, the thickness ζ of the explosive charge is calculated according to the principle of conservation of momentum.

[0167] According to the formula for conservation of momentum, ΓζSρ0V d =MV p +I, The result shows that ζ = 0.009 meters, which means the thickness of the medicine application is 9 millimeters.

[0168] Example 3

[0169] A welding method for an aluminum-copper composite laminar flow plate with fluid heat dissipation pipes on a ship is provided. The method involves using explosive welding to combine explosive-aluminum plate-gap-copper pipe array-gap-aluminum plate to form an aluminum-copper composite laminar flow plate. The aluminum plate set on top of the copper pipe array is a cover plate, i.e., a cladding, and the aluminum plate set below the copper pipe array is a base plate, i.e., a base layer. The cover plate, copper pipe array, and base plate are arranged in parallel. Figure 6 This is an assembly diagram of the aluminum-copper composite laminar flow plate structure prepared by explosive welding in Embodiment 3 of the present invention.

[0170] Specifically, the process parameters for explosive welding are determined according to the following steps:

[0171] Step 1: In this embodiment, the aluminum-copper composite laminar flow plate is a composite structure composed of an aluminum plate, a copper tube array, and an aluminum plate. The aluminum plates on both sides are the same size, and the copper tube array is sandwiched between the aluminum plates on both sides. Since the aluminum plates on both sides are the same size, in this embodiment, either aluminum plate can be used as the cladding plate in the explosive welding process, i.e., the cladding layer, while the other aluminum plate is the substrate, i.e., the base layer.

[0172] 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 a copper tube array laid on it, i.e., the copper tube array is located between the cladding plate 14 and the substrate 16, and the copper tube array consists of 5 independent copper tubes 15. The aluminum plate serving as substrate 16 has dimensions of 200 mm × 100 mm × 4 mm, i.e., the width B of substrate 16 is 100 mm, and the copper tubes 15 have dimensions of 200 mm in length, 3 mm in outer diameter, and 1 mm in wall thickness. The independent 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 15 are filled with paraffin wax.

[0173] In this embodiment, the explosive welding theoretically involves welding between the cladding plate and the copper tube, welding between the copper tube and the substrate, and welding between the cladding plate and the substrate. 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.

[0174] Step 2: Determine the impact velocity V during explosive welding based on the material parameters of the substrate and the cover plate. c The optional range;

[0175] Calculate the welding V of the cover plate and the substrate c Optional range:

[0176] Collision point velocity V c Minimum value V cmin =(2R) e (HV f +HV b ) / (ρ f +ρ b )) 1 / 2 = (10.6 × 2 × 0.294 × 10 9 / 2700) 1 / 2 =1520 (m / s);

[0177] Collision point velocity V c The maximum value V cmax It is 6400 meters per second.

[0178] Step 3: Based on the material parameters of the substrate and the cladding, determine the welding energy required for welding. Use the cladding kinetic energy as the welding energy source, and determine the cladding impact velocity V during explosive welding based on the minimum welding energy requirement. p Minimum value V pminThe 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 coating V p The specific value;

[0179] 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;

[0180] Minimum collision angle θ min =arcsin(192 / 6400)=1.72°;

[0181] The maximum value of the dynamic compressive equivalent stress caused by the cladding impact is set as the dynamic yield strength σ corresponding to the lower limit of the welding energy. S 3 times, maximum collision angle θ max =21.6°;

[0182] θ Ⅰ =7.2°, θ Ⅲ =5.2°

[0183] Determine the specific value of the collision angle θ:

[0184] The collision angle θ = 1.72° + 0.51 × (21.6° - 1.72°) = 11.9°.

[0185] Due to θ Ⅰ ≤θ, and θ Ⅲ ≤θ, 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 ;

[0186] Impact velocity of the cover plate V p =V c sinθ=1600×sin11.9°=330 meters / second.

[0187] Step 4: Based on the impact velocity V of the cover plate p Collision angle θ, explosive detonation velocity Vd The physical parameters of the substrate and the cladding plate and the explosive are used to determine the spacing A between the substrate and the cladding plate based on the conservation of function.

[0188] According to formula 1 / 2MV p 2 Calculate the kinetic energy of the copper tube with a cladding plate and paraffin filling when it is dropped onto the plate.

[0189] E 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.

[0190] Step 5: 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.

[0191] The formula for conservation of momentum is ΓζSρ0V d =MV p ,

[0192] The result shows that ζ = 0.015 meters, which means the thickness of the medicine application is 15 millimeters.

[0193] 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 method for designing explosive welding process parameters, characterized in that, The method includes the following steps: Step 1: Determine the base layer and cladding layer in explosive welding based on the unit area mass of the welding material, and set the base layer and cladding layer in parallel. Step 2: Determine the impact velocity V during explosive welding based on the material parameters of the base layer and the cladding layer. c The optional range; Step 3: Based on the material parameters of the base layer and the cladding layer, determine the welding energy required for welding. Use the kinetic energy of the cladding layer as the welding energy source, and determine the impact velocity V of the cladding layer 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 and coating impact velocity V p The specific value; Step 4: Based on the coating impact velocity V p Collision angle θ, explosive detonation velocity V d The physical parameters of the base layer and the explosive are used to determine the spacing A between the base layer and the base layer based on the conservation of function. Step 5: Based on the coating impact velocity V p Explosive detonation velocity V d The physical parameters of the coating and explosive are used to determine the explosive thickness ζ based on the conservation of momentum. In step 3, the welding energy and the kinetic energy of the cladding layer are directly proportional, and the lower limit of the welding energy and the impact velocity V of the cladding layer are related. p Minimum value V pmin The following conditions must be met: 1 / 2MV pmin 2 =E wmin =s b SH f bd Where: M is the mass of the coating, in kilograms; S is the area of ​​the coating, in square meters; ρ f H represents the density of the coating, expressed in kilograms per cubic meter. f The coating thickness is in meters; 1 / 2MV pmin 2 The minimum kinetic energy of the impact on the coating is expressed in joules. E represents the conversion rate of the minimum kinetic energy of the coating impact into the welding energy. wmin The lower limit of the welding energy is given, in joules; σ b β is the tensile strength of the cladding or base material, in Pascals; β is the minimum weld layer thickness as a percentage of the cladding thickness H. f The proportion, δ is the elongation of the weld layer, in percentages, dimensionless; In step 3, the stress failure criterion of the fourth strength theory is (σ 2 +3τ 2 ) 1 / 2 ≥σ S σ represents the dynamic compressive normal stress between the cladding and the base layer, in Pascals; σ and the impact velocity V of the cladding are also mentioned. p The longitudinal component of velocity V perpendicular to the base layer p cos(θ / 2) is directly proportional to it; τ is the shear stress between the cladding and the base layer, in Pascals; τ and the impact velocity V of the cladding are also related. p The lateral velocity component V parallel to the base layer p sin(θ / 2) is directly proportional; where θ is the collision angle; (σ 2 +3τ 2 ) 1 / 2 The dynamic compressive equivalent stress is expressed in Pascals; σ S The larger dynamic yield strength of the cladding and the base layer, in Pascals; In step 4, the formula for the conservation of function is P. C-J k0SA / cos(θ / 2)=1 / 2MV p 2 In the formula P C-J The pressure on the wavefront CJ of the explosive detonation wave is expressed in Pascals; k0 is the pressure adjustment coefficient, ranging from 0.6 to 0.7; S is the area of ​​the coating layer, in square meters; A is the distance between the base layer and the coating layer, in meters; θ is the impact angle, in degrees; M is the mass of the coating layer, in kilograms; V p The impact velocity of the coating is expressed in meters per second.

2. The method according to claim 1, characterized in that, In step 1, a flat plate or round tube with a smaller unit area mass is selected as the cladding layer in explosive welding, and a flat plate or round tube with a larger unit area mass is selected as the base layer in explosive welding. When the unit area mass of the flat plate or round tube is equal, either one is selected as the cladding layer or the base layer in explosive welding.

3. The method according to claim 1, characterized in that, In step 2, the velocity V at the collision point c Minimum value V cmin satisfy: V cmin =(2R e (HV f +HV b ) / (ρ f +ρ b )) 1 / 2 In the formula: R e Here is the Reynolds number, with a value of 10.6; HV f The Vickers hardness of the coating is expressed in Pascals (HV). b ρ represents the Vickers hardness of the substrate, measured in Pascals. f The density of the coating is expressed in kilograms per cubic meter; ρ b The density of the base layer is expressed in kilograms per cubic meter. Collision point velocity V c The maximum value V cmax The minimum sound velocity of the cladding layer and the sound velocity of the base layer is expressed in meters per second.

4. The method according to claim 1, characterized in that, According to the stress failure criterion of the fourth strength theory, when V p (2-cosθ) 1 / 2 ≥V pmin (2-cosθ) min ) 1 / 2 At that time, the dynamic compression equivalent stress (σ) 2 +3τ 2 ) 1 / 2 The dynamic yield strength σ of the overcoat and the base layer has been reached or exceeded. S ; Among them, V p V is the impact velocity of the coating. pmin The impact velocity V of the coating p The minimum value, in meters per second; θ is the collision angle, θ min The minimum collision angle is expressed in degrees.

5. The method according to claim 4, characterized in that, The highest value of the dynamic compressive equivalent stress is the dynamic yield strength σ corresponding to the lower limit of the welding energy. S 2 to 4 times.

6. The method according to claim 1, characterized in that, In step 5, the formula for the conservation of momentum is ΓζSρ0V. d =MV p In the formula, ζ is the thickness of the explosive charge, in meters; S is the area of ​​the coating, in square meters; ρ0 is the density of the explosive, in kilograms per cubic meter; V d V is the detonation velocity of the explosive, in meters per second; M is the mass of the coating, in kilograms; p The impact velocity of the coating layer is expressed in meters per second; Γ is the ratio of the momentum of the explosive acting in the direction of the coating layer to the total momentum of the explosive.

7. The method according to claim 6, characterized in that, The In the formula, γ is the adiabatic index of the explosive products, which is dimensionless; ζ is the thickness of the explosive layer, in meters; and N is the length of the coating layer, in meters, where N≥2.25ζ.

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