Welding structure and welding method for explosive welding of large-breadth composite tube plate

Abstract

The invention provides a welding structure and a welding method for explosive welding of a large-breadth composite tube plate, and relates to the technical field of explosive welding of metal composite plates. The lining plate is embedded in the blasting bed, and the upper surface of the lining plate is provided with a lining plate bearing surface; the lining plate bearing surface and the blasting bed bearing surface are coplanar and form a composite supporting surface together, and the composite supporting surface is used for supporting a base plate; the bottom of the foot pad is provided with a substrate abutting face used for abutting against the to-be-welded face of the substrate, and the top of the foot pad is provided with a covering plate supporting face used for supporting the covering plate. The explosive layer is arranged at the top of the covering plate, an exploder used for detonating is arranged in the explosive layer, the exploder is aligned with the geometric center of the covering plate, and the vertical projection of the exploder in the welding direction is overlapped with the lining plate; through a composite supporting surface formed by the lining plate pre-buried in the blasting bed and the blasting bed, the partition bearing of the blasting impact force is realized, and the deformation of the plate during the explosive welding of the large-breadth composite tube plate is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of explosive welding of metal composite plates, and in particular to a welding structure and a welding method for explosive welding of large-area composite tube plates. Background Art

[0002] In the fields of petrochemicals, nuclear power, and marine engineering, composite tube sheets, as key pressure-bearing components, need to have high strength, corrosion resistance, and high sealing properties. Traditional composite tube sheet manufacturing mostly uses explosive welding technology, which uses explosive detonation to drive the covering plate to impact the base plate at high speed to achieve interface metallurgical bonding. However, with the development of large-scale equipment, the demand for large-format composite tube sheets has increased sharply. Large-format composite tube sheets often refer to composite tube sheets with a diameter of more than 4600mm. During explosive welding, the explosion impact energy is highly concentrated at the detonation center. The traditional explosive bed structure cannot effectively suppress the plastic collapse of the base plate at the explosion center. The deformation is difficult to predict, which has a significant impact on the quality of the explosive composite and reduces the overall performance of the composite tube sheet.

[0003] Therefore, there is an urgent need to propose a welding structure that can reduce the deformation of the plate during the explosive welding of large-scale composite tube sheets and can better adapt to the explosive welding of large-scale composite tube sheets. Summary of the Invention

[0004] The purpose of the present invention is to provide a welding structure and welding method for explosive welding of large-scale composite tube sheets to solve the problems existing in the above-mentioned prior art and to reduce the deformation of the plates during explosive welding of large-scale composite tube sheets.

[0005] To achieve the above-mentioned object, the present invention provides the following solution: a welding structure for explosive welding of large-scale composite tube sheets is provided, comprising:

[0006] A pop-up bed, wherein the top of the pop-up bed has a pop-up bed bearing surface;

[0007] A lining plate, the lining plate being embedded in the blasting bed, the upper surface of the lining plate having a lining plate bearing surface; the lining plate bearing surface and the blasting bed bearing surface being coplanar, and the two together forming a composite supporting surface, the composite supporting surface being used to support the substrate;

[0008] A pad foot, wherein the bottom of the pad foot has a substrate abutting surface for abutting against the surface to be welded of the substrate, and the top of the pad foot has a cover plate supporting surface for supporting the cover plate;

[0009] and an explosive layer arranged on top of the covering plate, wherein a detonator for detonation is provided in the explosive layer, the detonator is aligned with the geometric center of the covering plate, and the vertical projection of the detonator along the welding direction overlaps with the lining plate.

[0010] As an embodiment, the outer edge of the lining plate is provided with a slope, and the top of the slope extends to the bearing surface of the lining plate.

[0011] As an embodiment, the top of the slope surface smoothly transitions to the liner bearing surface through rounded corners.

[0012] As an embodiment, the blast bed is composed of sand, the liner is a steel plate, and the liner is embedded in the blast bed through a pre-pressing process.

[0013] As an embodiment, the geometric centers of the lining plate, the base plate and the cover plate are all collinear with the same vertical axis.

[0014] As one embodiment, the foot is a V-shaped foot, and the tip of the V-shaped foot faces the geometric center of the substrate, the V-shaped surface at the bottom of the V-shaped foot is the substrate abutment surface, and the V-shaped surface at the top of the V-shaped foot is the cover plate support surface.

[0015] As an embodiment, it further includes a limit stopper, which is fixed to the top edge of the cover plate and encloses an explosive accommodating area.

[0016] As an embodiment, the limit stopper is made of cardboards, and the cardboard interfaces are sealed by tape.

[0017] As an embodiment, the detonator further includes a detonator. An explosive accommodating chamber is provided in the detonator, and the detonator is inserted into the explosive accommodating chamber.

[0018] A welding method for a large-area composite tube sheet explosion welding structure comprises the following steps:

[0019] S1. Substrate pretreatment: Level the substrate using a leveling machine to ensure that the flatness of the substrate is ≤1 mm / m; polish the substrate using a polishing device to ensure that the smoothness of the substrate is ≤2.0 μm;

[0020] S2. Pretreatment of the covering plate: leveling the covering plate with a leveling machine; polishing the covering plate with a polishing device to make the surface finish of the covering plate ≤1.6 μm;

[0021] S3. Preparation of composite support surface: embedding a lining plate in the blasting bed so that the lining plate bearing surface and the blasting bed bearing surface are coplanar to form a composite support surface, and arranging the substrate on the composite support surface;

[0022] S4. Setting the foot: Setting the foot on the substrate, with the substrate contact surface of the foot contacting the substrate and the surface of the substrate to be welded; setting the cover plate on the cover plate supporting surface of the foot, so that there is a gap between the cover plate and the substrate;

[0023] S5. Laying an explosive layer: Laying an explosive layer on top of the cover plate so that the detonator is aligned with the geometric center of the cover plate, and the downward vertical projection of the detonator overlaps with the lining plate.

[0024] Compared with the prior art, the present invention has achieved the following technical effects:

[0025] 1. The present invention is suitable for explosive welding of large-scale composite tube sheets, and ensures that the large-scale tube sheets after explosive welding have good overall flatness:

[0026] ①. Center detonation:

[0027] The present invention adopts a central detonation method, in which the detonator is aligned with the geometric center of the cover plate, so that the explosion energy is fully and evenly diffused in the radial direction on the cover plate with the geometric center as the starting point, which can suppress the asymmetric deformation of the surrounding area of ​​the detonation point, and ensure that the bonding interface of the large-scale composite tube plate has good uniformity and bonding strength during explosion welding.

[0028] ②、Composite support surface partition bearing:

[0029] The composite support surface formed by the liner pre-buried in the blast bed and the blast bed can realize the zoned bearing of the explosion impact force; the projection of the detonator overlaps with the liner, ensuring that the explosion energy during detonation is concentrated on the liner support area, and the collapse and deformation of the substrate at the center of the explosion is directly suppressed by the liner; the blast bed absorbs the impact force at the edge of the explosion, thereby reducing the deviation of the overall flatness of the substrate and the deformation of the plate during the explosion welding of large-scale composite tube sheets, ensuring that the large-scale composite tube sheets after explosion welding have good overall flatness.

[0030] Other technical solutions of the present invention also have the following technical effects:

[0031] 2. The outer edge of the liner is provided with a slope, the top of the slope extends to the liner bearing surface, and the liner is used to provide rigid support to the substrate. The top of the slope is transitioned to the liner bearing surface through a rounded corner. The rounded corner serves as a transition zone, which can disperse stress concentration and avoid grain boundary tearing or indentation defects caused by right-angle edges during explosive welding.

[0032] 3. The blast bed is made of sand, and the liner is a steel plate. The liner is embedded in the blast bed through a pre-pressing process. In this way, the liner pre-embedded in the blast bed and the flexible sand blast bed form a composite support interface, which realizes the partitioned bearing of the explosion impact force, including the rigid support area and the flexible support area. In the rigid support area, due to the greater rigidity of the liner, the collapse and deformation of the substrate at the center of the explosion is directly suppressed by the liner; in the flexible energy absorption area, the sand in the blast bed absorbs the edge stress by deformation; the present invention reduces the overall flatness deviation of the substrate after the explosion composite through the rigid-flexible coupling support design. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0034] Figure 2 It is a partial enlarged schematic diagram of the overall structure of the present invention;

[0035] Figure 3 This is a schematic diagram of the liner of the present invention;

[0036] Figure 4 It is a schematic diagram of the arrangement of the footrests of the present invention.

[0037] Among them, 1. blasting bed; 2. lining plate; 3. foot pad; 4. explosive layer; 5. base plate; 6. cover plate; 7. detonator; 8. slope surface; 9. lining plate bearing surface; 10. limit stop; 11. detonator. DETAILED DESCRIPTION

[0038] Example 1:

[0039] This embodiment provides a welding structure for explosive welding of large-format composite tube sheets. The large-format composite tube sheet of the present invention refers to a composite tube sheet with a diameter exceeding 4600 mm. It comprises an explosive bed 1, a liner 2, a foot 3, and an explosive layer 4. The explosive bed 1 serves as the bottom support structure, with an explosive bed bearing surface provided on its top. The liner 2 is embedded in the explosive bed 1. In one embodiment, the liner 2 is a rigid liner made of stainless steel, with greater rigidity than the explosive bed 1. A liner bearing surface 9 is provided on its upper surface. The liner bearing surface 9 and the explosive bed bearing surface are coplanar, forming a composite support surface that supports a base plate 5. The bottom surface of the base plate 5 serves as the support surface, abutting both the liner bearing surface 9 and the explosive bed bearing surface. The liner 2 and the explosive bed 1 simultaneously support the base plate 5. The foot 3 has a base plate abutting surface at its bottom, and the foot 3 is positioned on the surface of the base plate 5 to be welded via the base plate abutting surface. The top of the footing 3 is provided with a cladding support surface, through which the footing 3 abuts the cladding 6. In one embodiment, the footing 3 supports the cladding 6, keeping it parallel to the base plate 5, creating a gap between them. An explosive layer 4 is arranged atop the cladding 6. Within the explosive layer 4 is a detonator, connected to the explosives within the explosive layer 4; the detonator serves as a detonation point for detonating the explosives within the explosive layer 4. A predetermined detonation point is provided on the top surface of the cladding 6. In one embodiment, this predetermined detonation point is located at the geometric center of the top of the cladding 6, with the detonator vertically aligned with the predetermined detonation point on the cladding 6. This means that the detonator is also vertically aligned with the geometric center of the cladding 6. Furthermore, the detonator's vertical downward projection along the welding direction overlaps with the liner 2. In one embodiment, the detonator's vertical downward projection can completely fall onto the liner 2.

[0040] Working principle: The lining plate 2 is embedded into the blasting bed 1. As an embodiment, the lining plate 2 is pre-buried in the central area of ​​the blasting bed 1 so that the lining plate bearing surface 9 of the lining plate 2 is coplanar with the blasting bed bearing surface of the blasting bed 1, forming a composite support surface together. The base plate 5 is placed horizontally on the composite support surface, with the bottom surface of the base plate 5 simultaneously abutting against the blasting bed 1 and the lining plate 2; a plurality of foot pads 3 are placed on the surface to be welded of the base plate 5, with the substrate abutting surface of the foot pads 3 abutting against the surface to be welded of the base plate 5; the cover plate 6 is set on the cover plate supporting surface of the foot pads 3, with the boundary of the projection of the cover plate 6 on the base plate 5 exceeding the edge of the base plate 5 by a preset distance; an explosive layer 4 is arranged on the cover plate 6 so that the detonator in the explosive layer 4 is aligned with the geometric center of the cover plate 6, and at the same time, the vertical downward projection of the detonator can overlap with the lining plate 2. During operation, the detonator is controlled to detonate. The detonator serves as the center of the explosion and detonates the explosive layer 4. The explosion composite instantly generates ultra-high pressure, causing the covering plate 6 to make a high-speed tilt collision with the substrate 5, performing explosion welding, and realizing one-time explosion welding forming. Since the explosion center has a large impact force, the lining plate 2 supports the part of the substrate 5 located at the explosion center. The lining plate 2 can suppress the collapse deformation of the substrate 5 in the explosion center area, reduce the deformation of the substrate 5, and reduce the plastic deformation at the detonation point. Ensure the overall flatness of the composite tube sheet after the explosion composite, and the explosion bed 1 has a flexible absorption capacity to reduce stress concentration at the edge.

[0041] In this embodiment, the outer edge of the liner 2 is provided with a slope 8, the top of which extends to the liner bearing surface 9. When the ultra-high pressure generated by the explosive composite moment causes the cover plate 6 to collide with the base plate 5 at a high speed and in an oblique manner, the base plate 5 is also forced downward by the impact. The liner 2 provides rigid support for the base plate 5. In the area of ​​the slope 8 of the liner 2, the slope 8 allows the base plate 5 in the corresponding area to cushion downward movement, resulting in a certain degree of controllable deformation of the base plate 5.

[0042] In this embodiment, the top of the slope 8 transitions to the liner bearing surface 9 through a transition angle. The transition angle is preferably a chamfered angle. No obvious sharp corners or edges should appear at the transition angle to fully avoid the phenomenon of stress concentration. The chamfered angle serves as a transition zone. The chamfered angle can disperse stress concentration and avoid grain boundary tearing or indentation defects caused by right-angle edges during explosive welding. If the edge of the liner 2 is not polished and the slope 8 is not opened, the liner 2 and the substrate 5 will form a longitudinal shear, the substrate 5 will form an indentation or the internal grain structure will be destroyed, seriously affecting the performance of the substrate 5. By polishing the slope 8 and providing a chamfered transition zone, the substrate 5 can be protected.

[0043] In this embodiment, the explosive bed 1 is composed of sand and soil. The explosive bed bearing surface on the top of the explosive bed 1 can be compacted by a compacting machine, and the explosive bed 1 has a certain degree of flexibility. The liner 2 is a steel plate, and the liner 2 is embedded in the explosive bed 1 through a pre-pressing process. Specifically, the staff can embed the liner 2 into the explosive bed 1 by pressing. The composite support surface formed by the liner 2 pre-embedded in the explosive bed 1 and the explosive bed 1 of flexible sand and soil realizes the zoned bearing of the explosive impact force, including a rigid support area and a flexible support area. In the rigid support area, due to the greater rigidity of the liner, the collapse and deformation of the substrate 5 at the center of the explosion is directly suppressed by the liner 2; in the flexible energy absorption area, the sand of the explosive bed 1 absorbs the edge stress by deformation; through the rigid-flexible coupling support design, the overall flatness deviation of the substrate 5 after the explosion composite is reduced.

[0044] In this embodiment, the geometric center of the lining plate 2, the geometric center of the base plate 5, and the geometric center of the cover plate 6 are all collinear with the same vertical axis. That is, the lining plate 2, the base plate 5, and the cover plate 6 are aligned vertically. In this way, the detonator can be aligned with the geometric center of the lining plate 2, and a central detonation method is adopted. As an embodiment, the cross-sections of the lining plate 2, the base plate 5, and the cover plate 6 are all circular. The centers of the lining plate 2, the base plate 5, and the cover plate 6 are located on the same vertical axis. The diameter of the lining plate 2 can account for 10% to 20% of the diameter of the base plate 5. Of course, the ratio of the diameter of the lining plate 2 to the diameter of the base plate 5 can be adjusted according to actual conditions.

[0045] In this embodiment, the structure of the foot 3 is V-shaped, forming a V-shaped foot, the tip of the V-shaped foot is facing the geometric center of the substrate 5, and the V-shaped foot is horizontally arranged on the surface to be welded of the substrate 5. The V-shaped foot includes relative V-shaped surfaces, namely a first V-shaped surface and a second V-shaped surface. The first V-shaped surface at the bottom of the V-shaped foot is arranged on the surface to be welded of the substrate 5, and the first V-shaped surface is the substrate abutting surface; the second V-shaped surface at the top of the V-shaped foot abuts against the cover plate 6, and the second V-shaped surface is the cover plate supporting surface. The V-shaped foot can stably support the cover plate 6. During explosion welding, the gas between the cover plate 6 and the substrate 5 will be quickly discharged to the outside to ensure a good welding effect. Since the tip of the V-shaped foot is facing the explosion center, the V-shaped edge of the V-shaped foot can play a role in diversion, ensuring that the gas can be quickly discharged to the outside, reducing the defects of explosion welding. At the same time, during explosion welding, the V-shaped foot at the edge can also be discharged to the outside in time.

[0046] In this embodiment, a limit stopper 10 is installed on the top of the cover plate 6. This limit stopper 10 is fixed at the edge of the top of the cover plate 6 and forms an explosives frame. In one embodiment, the limit stopper 10 is perpendicular to the top surface of the cover plate 6. An explosives storage area is enclosed within the limit stopper 10. This area is located at the top of the cover plate 6 and is axially sealed. The explosives storage area is evenly filled with explosives.

[0047] In this embodiment, the stopper 10 is constructed from multiple pieces of cardboard, sealed with tape at the edges to prevent leakage during later explosive placement. In one embodiment, the cardboard should be perpendicular to the cover plate 6, and the explosives storage area should coincide with the boundary of the cover plate 6.

[0048] In this embodiment, the detonator includes a detonator 7, which is provided with an explosives chamber. A detonator 11 can be inserted into the chamber, and the explosives in the chamber can be detonated by the detonator 11. Detonator 11 is provided with a signal receiver, which is a digital electronic detonator. The signal receiver in the digital electronic detonator can receive external signals and directly act on the detonating portion of the digital electronic detonator to detonate the explosives in the chamber; that is, the digital electronic detonator can be detonated remotely. In one embodiment, the detonator 7 includes a paper detonator, and the explosives chamber is provided in the paper detonator. The diameter of the explosives chamber is 25 mm.

[0049] Example 2:

[0050] This embodiment provides a welding method for explosive welding of large-scale composite tube sheets, using the welding structure for explosive welding of large-scale composite tube sheets in the first embodiment, and comprising the following steps:

[0051] S1. Substrate preparation: Using a high-precision, ultra-wide intelligent rolling mill, ultra-wide steel plates that meet the requirements of GB / T713.2-2023 are produced. The diameter of the ultra-wide steel plates is usually not less than 4600 mm, and the ultra-wide steel plates are used as substrates 5.

[0052] S2. Substrate pretreatment: Use a seven-roller leveling machine to level the substrate 5 to 1 mm / m, meeting the internal control requirements for explosive welding quality; use a 60-mesh sanding belt to grind the substrate bonding surface to remove surface rust and oxide layer, and then use a 100-mesh flap wheel to polish the substrate 5 to a surface finish of ≤2.0 μm;

[0053] S3. Cladding plate preparation: Cladding plate 6 uses a fully automatic plasma + argon arc welding machine to splice multiple steel plates into the specified feeding size, and uses a louver blade to grind the weld to make it flush with the parent material;

[0054] S4. Pretreatment of the covering plate: The covering plate 6 is leveled. As one embodiment, the flatness of the covering plate 6 is ≤1 mm / m. The surface of the covering plate 6 is polished using an 80-mesh sanding belt to remove the oxide layer on the upper surface of the covering plate 6. Local minor scratches and pits are polished away using a straight grinder. The covering plate 6 is then polished using a 120-mesh flap wheel to a surface finish of ≤1.6 μm, with no local pits or pits.

[0055] S5. Preparation of composite support surface: A liner 2 is embedded in the blasting bed 1 so that the liner bearing surface 9 is coplanar with the blasting bed bearing surface, thereby forming a composite support surface. In one embodiment, the cross-sectional area of ​​the liner 2 is circular and the diameter of the liner 2 is 300 mm. Thus, a 300 mm φ liner 2 can be embedded in the center of the blasting bed 1. The outer edge of the liner 2 is polished with a 20° slope 8, and the slope 8 is transitioned to the liner bearing surface 9 by chamfering.

[0056] S6. Place the substrate: Place the substrate 5 horizontally on the blasting bed 1, with the substrate 5 supported on the composite support surface, and the bottom of the substrate 5 abutting against the blasting bed 1 and the liner 2 at the same time; clean the surface of the substrate 5 to be welded with acetone; as an embodiment, the geometric center of the liner 2 is aligned vertically with the geometric center of the substrate 5;

[0057] S7. Set the pads: Set the pads 3 on the substrate 5, with the substrate-contacting surface of the pads 3 contacting the surface of the substrate 5 to be welded; when the pads 3 are V-shaped, place the V-shaped pads in a ring, with the V-angle of the V-shaped pads aligned with the geometric center of the substrate 5, and with adjacent V-shaped pads spaced 350 mm apart; as one embodiment, the V-shaped pads can be placed in a first circular ring and a second circular ring, respectively; the first circular ring is located outside the second circular ring, and the centers of the first and second circular rings coincide with the geometric center of the substrate 5; when placed, the outermost V-shaped pad is no more than 5 mm from the outer edge of the substrate 5;

[0058] S8. Place the cover plate: Place the cover plate 6 on the cover plate support surface of the foot 3, with the cover plate 6 parallel to the base plate 5, so that there is a gap between the cover plate 6 and the base plate 5. In one embodiment, the gap is a space with a uniform height, and the cover plate 6 uniformly extends beyond the base plate 5 by a preset size margin on all sides. When hoisting the cover plate 6, use four plate-type hooks evenly distributed around the cover plate 6, and use a vacuum suction cup in the middle to cooperate and lift the cover plate 6 to ensure the levelness of the cover plate 6, facilitate cleaning, and prevent local bending and excessive plastic deformation. Then, clean the surface of the cover plate 6 to be welded with acetone.

[0059] S9. Arrange the limit stops: Arrange the explosive layer 4 on the top of the cover plate 6 so that the detonator is aligned with the geometric center of the cover plate 6, and the downward vertical projection of the detonator overlaps with the lining plate 2; as an embodiment, when laying the explosive layer 4, first arrange the limit stops 10, and set a circle of limit stops 10 on the outer periphery of the top surface of the cover plate 6 with cardboard and tape. The limit stops 10 constitute an explosive frame. The cardboard is required to be perpendicular to the cover plate 6, and the range of the explosive frame is consistent with the boundary of the cover plate 6. The cardboard interface position must also be sealed with tape to avoid leakage of explosives when the explosives are laid later; then, the detonator 7 in the detonator is set at the geometric center position of the cover plate 6. The detonator 7 is a φ25mm paper detonator.

[0060] S10, laying explosives: prepare density 0.85~0.90g / cm 3 Explosive welding explosives with a detonation velocity of 2000-2100m / s and a strength of approximately 9mm are used, and they have good flowability. The explosives for explosive welding are placed in the explosive frame, and then the height of the explosives is adjusted to a pre-calculated range using a special tool. The height of the explosives within 400mm of the edge of the cladding plate 6 is reduced by 5-8mm, resulting in fine and uniform corrugations on the bonding surface, reducing the probability of coarse corrugations. This also effectively reduces the amount of explosive thinning at the edge, making the thickness of the entire cladding layer more uniform.

[0061] S11. Place the detonator: Add a small amount of high-intensity explosive to the paper detonator pre-placed at the geometric center of the cover plate 6. Then, vertically place the digital electronic detonator at the center of the high-intensity explosive so that the energy-gathering hole at the bottom of the digital electronic detonator contacts the cover plate 6. In one embodiment, the energy-gathering hole at the bottom of the digital electronic detonator abuts the geometric center of the cover plate 6.

[0062] S12. Explosion welding: Detonate digital electronic detonators through remote control to complete explosion welding.

[0063] The present invention also offers the following advantages: 1. The large-format composite tubes of the present invention utilize explosive welding, a single-step explosive composite forming process. This method, for a wide range of applications such as petroleum, chemical engineering, electric power, and marine engineering, produces large-format, weld-free, high-strength, high-performance composite tube sheets. This significantly improves safety while reducing production costs, avoiding the risk of leakage and failure of the overall equipment caused by performance degradation at weld locations and performance differences in the heat-affected zone.

[0064] 2. The large-scale composite tube sheet of the present invention is formed by one-time explosion. The problems that may be encountered in the actual production process of the large-scale composite tube sheet can be predicted in advance, and preventive measures can be taken. It is low-cost and high-efficiency. After ultrasonic non-destructive testing, the bonding rate reaches 99.9%. The detonator area is φ25mm, and subsequent processing can be repaired by surfacing welding. The factory qualified rate reaches 100%.

[0065] 3. The large-format composite tube sheet produced by the present invention has a shear strength of ≥280Mpa after mechanical property testing, far exceeding the requirement of 210Mpa in NB / T47002.1-2019.

[0066] 4. Because the bottom of the detonation position is protected from deformation by liner 2, subsequent leveling after explosive welding allows for a flatness of 2mm-3mm across the entire plate. This effectively reduces the difficulty of subsequent machining, turning, and drilling of the composite tube sheet. It also significantly reduces the additional cost of thickening the material to compensate for flatness deviations, achieving the goal of increasing efficiency and reducing costs. This has also been recognized and affirmed by machining manufacturers, with no issues of tool locking or tool breakage occurring during drilling.

[0067] 5. By adopting the operation details and preventive control in the explosive welding process of the present invention, it is possible to realize the processing and forming of large-scale explosively welded composite panels composed of various materials.

[0068] Example 3:

[0069] A. Material selection

[0070] Substrate selection: Substrate 5 uses Q345R container steel plate, with specific specifications and dimensions: thickness 43mm, diameter 4730mm;

[0071] Cladding plate selection: Cladding plate 6 is made of austenitic stainless steel S31603, with specific specifications and dimensions: thickness 8mm, diameter 4780mm;

[0072] B. Specific production method

[0073] 1) The substrate 5 is hoisted to a seven-roller leveling machine for leveling to achieve a flatness requirement of 1 mm / M, and then the surface is derusted and scaled with a 60-mesh sand belt, and then polished with a 100-mesh flap wheel to a smoothness of 1.6 to 1.8 μm, thereby obtaining a substrate 5 to be explosively composited.

[0074] 2) Use a louver blade to grind both the front and back sides of the weld of the welded cover plate 6 until they are flush with the base material, then use a leveling machine to level them. Use an 80-mesh hand-propelled sander to remove the surface oxides on the joint surface of the cover plate 6. The joint surface of the cover plate 6 is the surface to be welded, revealing the metallic luster. Then use a 120-mesh louver wheel to polish it to a joint surface finish that meets the requirement of ≤1.6μm. At the same time, there must be no other surface defects such as oil, debris, pits, etc. on the joint surface, thus obtaining a cover plate 6 to be explosively bonded.

[0075] 3) In the center of the prepared blasting bed 1, a lining board 2 with a diameter of 300 mm and a slope of ∠20° is pre-placed, and a layer of fine sand with a thickness of about 5 mm is laid on it. Then, the base plate 5 is placed horizontally on the blasting bed 1, with the center of the base plate 5 above the lining board 2.

[0076] 4) Use four plate-type hooks and the vacuum suction cup in the middle to lift the cover plate 6 flatly, and then clean the joint surface of the cover plate 6 with acetone.

[0077] 5) Clean the bonding surface of substrate 5 with acetone. The bonding surface of substrate 5 is the surface to be welded. Then evenly place V-shaped pads with a height of 12 mm. The V-shaped pads are placed in a circular shape with a spacing of 350 mm between each other. When placed on the four sides, they should be no more than 5 mm away from the outer edge of substrate 5.

[0078] 6) Place the cover plate 6 horizontally with the joint surface facing downward on top of the V-shaped foot. After placement, the edge of the cover plate 6 evenly exceeds the surface of the base plate 5. At the same time, be careful not to bring any other debris into the joint surface between the base plate 5 and the cover plate 6. Then, place the detonator at the center of the cover plate 6. The detonator includes a detonator 7.

[0079] 7) Use cardboard and tape to set a circle of limit blocks 10 with a height of not less than 70mm around the parallel covering plate 6. The limit blocks 10 form the explosive frame. The cardboard must be perpendicular to the covering plate, and the scope of the explosive frame must be consistent with the boundary of the covering plate 6. The cardboard interface must also be sealed with tape. Then, place the prepared explosive in the explosive frame with a detonation velocity of 2036m / s, a force of 8.3mm, and a density of 0.87g / cm 3 The special explosives are preset at a height of 55mm. The height of the explosives placed within 400mm from the edge of the covering plate is appropriately reduced to 47-50mm.

[0080] 8) A small amount of high-intensity explosive is added to the detonator 7 pre-installed in the cover plate 6. A digital electronic detonator is then placed vertically at the center of the detonator 7, with the energy-focusing hole at the bottom contacting the cover plate 6. The digital electronic detonator is then detonated, resulting in a large-scale, one-shot explosively formed composite tube sheet. The composite tube sheet is labeled S31603+Q345R(8+43)*φ4730mm.

[0081] Example 4:

[0082] A. Material selection

[0083] Substrate selection: Substrate 5 uses 16MnⅢ forgings, with specific specifications and dimensions: thickness 95mm, diameter 4830mm;

[0084] Cladding plate selection: Cladding plate 6 is made of S31008 stainless steel, with the following specifications: thickness 6mm, diameter 4880mm;

[0085] B. Specific production method

[0086] 1) The substrate 5 is polished with a 60-mesh sand belt to remove the turning lines, and then polished with a 100-mesh flap wheel to obtain a substrate 5 to be explosively composited.

[0087] 2) Use a louver blade to grind both the front and back sides of the weld of the welded cover plate 6 until they are flush with the base material, then use a leveling machine to level them. Use an 80-mesh hand-propelled sander to remove the surface oxides on the joint surface of the cover plate 6 to reveal the metallic luster, and then use a 120-mesh louver wheel to polish it to a joint surface finish that meets the requirement of ≤1.6μm. At the same time, there must be no other surface defects such as oil, debris, pits, etc. on the joint surface, thus obtaining a cover plate 6 to be explosively composited.

[0088] 3) In the center of the prepared blasting bed 1, a lining board 2 with a diameter of 300 mm and a slope 8 with a polished edge of ∠20° is pre-placed, and a layer of fine sand with a thickness of about 5 mm is laid on it. Then, the base plate 5 is placed horizontally on the blasting bed 1, and the center of the base plate 5 is above the lining board 2.

[0089] 4) Use four plate-type hooks and the middle vacuum suction cup to lift the cover plate 6 flatly, and then clean the joint surface of the cover plate 6 with acetone.

[0090] 5) Clean the bonding surface of the substrate 5 with acetone, and then evenly place V-shaped pads with a height of 10 mm. The V-shaped pads are placed in a circular shape with a spacing of 350 mm between each other, and the four edges are placed no more than 5 mm away from the edge.

[0091] 6) Place the cover plate 5 horizontally with the joint surface facing downward on top of the V-shaped foot. After placement, the edge of the cover plate 6 evenly exceeds the surface of the base plate 5. At the same time, be careful not to bring any other debris into the joint surface between the base plate 5 and the cover plate 6. Then, place the detonator 7 at the center of the cover plate 6.

[0092] 7) Use cardboard and tape to set a circle of limit blocks 10 with a height of not less than 70mm around the parallel covering plate 6. The limit blocks 10 form the explosive frame. The cardboard must be perpendicular to the covering plate 6, and the scope of the explosive frame must be consistent with the boundary of the covering plate 6. The cardboard interface must also be sealed with tape. Then, place the prepared explosives in the explosive frame with a detonation velocity of 2010m / s, a force of 8.0mm, and a density of 0.85g / cm 3 The special explosives are preset at a height of 46mm. The height of the explosives within 400mm from the edge of the covering plate is appropriately reduced to 38-41mm.

[0093] 8) A small amount of high-intensity explosive is added to the pre-installed detonator 7 in the cover plate 6. A digital electronic detonator is then placed vertically at the center of the detonator 7, with the energy-focusing hole at the bottom contacting the cover plate 6. The digital electronic detonator is then detonated, resulting in a large-scale, single-shot explosively formed composite tube sheet. The composite tube sheet is labeled S31008+16MnIII(6+95)*φ4830mm.

Claims

1. A welding structure for explosion welding of large-scale composite tube sheets, characterized in that: include: A pop-up bed (1), wherein the top of the pop-up bed (1) has a pop-up bed bearing surface; A lining plate (2), the lining plate (2) being embedded in the explosion bed (1), the upper surface of the lining plate (2) having a lining plate bearing surface (9); the lining plate bearing surface (9) and the explosion bed bearing surface are coplanar, and the two together form a composite supporting surface, and the composite supporting surface is used to support a base plate (5); A pad foot (3), wherein the bottom of the pad foot (3) has a substrate abutting surface for abutting against the surface to be welded of the substrate (5), and the top of the pad foot (3) has a cover plate supporting surface for supporting the cover plate (6); and an explosive layer (4), wherein the explosive layer (4) is arranged on the top of the covering plate (6), wherein a detonator for detonation is arranged in the explosive layer (4), wherein the detonator is aligned with the geometric center of the covering plate (6), and wherein the vertical projection of the detonator along the welding direction overlaps with the lining plate (2).

2. The welding structure for explosion welding of large-area composite tube sheets according to claim 1 is characterized in that: The outer edge of the lining plate (2) is provided with a slope surface (8), and the top of the slope surface (8) extends to the lining plate bearing surface (9).

3. The welding structure for explosion welding of large-area composite tube sheets according to claim 2 is characterized in that: The top of the slope surface (8) smoothly transitions to the lining plate bearing surface (9) through rounded corners.

4. The welding structure for explosion welding of large-area composite tube sheets according to claim 1 is characterized in that: The explosion bed (1) is made of sand, the lining plate (2) is a steel plate, and the lining plate (2) is embedded in the explosion bed (1) through a pre-pressing process.

5. The welding structure for explosion welding of large-area composite tube sheets according to claim 1 is characterized in that: The geometric centers of the lining plate (2), the base plate (5) and the cover plate (6) are all colinear with the same vertical axis.

6. The welding structure for explosion welding of large-area composite tube sheets according to claim 1 is characterized in that: The foot (3) is a V-shaped foot, and the tip of the V-shaped foot faces the geometric center of the base plate (5), the V-shaped surface at the bottom of the V-shaped foot is the base plate abutment surface, and the V-shaped surface at the top of the V-shaped foot is the cover plate support surface.

7. The welding structure for explosion welding of large-area composite tube sheets according to claim 1 is characterized in that: It also comprises a limit stopper (10), wherein the limit stopper (10) is fixed to the top edge of the cover plate (6), and the limit stopper (10) encloses an explosive accommodating area.

8. The welding structure for explosion welding of large-area composite tube sheets according to claim 7 is characterized in that: The limit stopper (10) is formed by splicing cardboards, and the interface of the cardboards is sealed by adhesive tape.

9. The welding structure for explosion welding of large-area composite tube sheets according to claim 1, characterized in that: It also comprises a detonator (11), wherein an explosive accommodating chamber is arranged in the detonator, and the detonator (11) is inserted into the explosive accommodating chamber.

10. A welding method for a welding structure for explosion welding of large-area composite tube sheets according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, substrate pretreatment: performing a leveling treatment on the substrate (5) by means of a leveling machine, so that the flatness of the substrate (5) is ≤1 mm / m; performing a grinding treatment on the substrate (5) by means of a grinding device, so that the smoothness of the substrate (5) is ≤2.0 μm; S2, pretreatment of the cover plate: leveling the cover plate (6) with a leveling machine; grinding the cover plate (6) with a grinding device, so that the surface finish of the cover plate (6) is ≤1.6 μm; S3, preparation of a composite support surface: embedding a lining plate (2) in the blasting bed (1) so that the lining plate bearing surface (9) and the blasting bed bearing surface are coplanar to form a composite support surface, and arranging the substrate (5) on the composite support surface; S4, setting the pad foot: setting the pad foot (3) on the substrate (5), with the substrate contact surface of the pad foot (3) contacting the surface of the substrate (5) to be welded; setting the cover plate (6) on the cover plate support surface of the pad foot (3), so that there is a gap between the cover plate (6) and the substrate (5); S5. Laying out the explosive layer (4): Laying out the explosive layer (4) on the top of the cover plate (6), aligning the detonator with the geometric center on the cover plate (6), and making the downward vertical projection of the detonator overlap with the lining plate (2).

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