A large-size tin-phosphor bronze / Q235B composite plate and a preparation method thereof

Abstract

The application discloses a large-size tin-phosphor bronze / Q235B composite plate and a preparation method thereof, and belongs to the field of material forming. The method uses a Q235B steel plate as a base plate and a tin-phosphor bronze plate as a composite plate, lays, from bottom to top, a backing plate, the Q235B steel plate, a supporting column, the tin-phosphor bronze plate, a protective layer, an enclosure structure, a low-explosive-speed rock expanded ammonium nitrate oil explosive layer and an inert layer on an explosion field, and then causes the tin-phosphor bronze plate and the Q235B steel plate to collide at a high speed by detonating the explosive, so that metallurgical combination is caused, a large-size tin-phosphor bronze / Q235B composite plate is obtained, the interface bonding rate of the obtained composite plate is greater than 98%, the interface shear strength is greater than 274 MPa, and the composite plate has the excellent high strength, wear resistance and other performances of the tin-phosphor bronze and the low-cost advantage of the Q235B steel.

Description

Technical Field

[0001] This invention relates to the field of explosively welded metal composite plates, specifically providing a large-size tin-phosphor bronze / Q235B composite plate and its preparation method, belonging to the field of material forming. Background Technology

[0002] Tin-phosphor bronze is a high-performance elastic copper alloy with advantages such as high strength, good elasticity, wear resistance, and corrosion resistance. It is currently the most widely used and consumed elastic copper alloy material, and is extensively used in the manufacture of electronic components such as electrical switches, relays, connectors, and springs. However, the expensive tin element contained in this alloy keeps its raw material costs high, limiting its further development.

[0003] On the other hand, Q235B steel is widely used in construction and engineering structures due to its low cost, mature technology, and good comprehensive mechanical properties. However, in environments where high performance requirements such as wear resistance are needed, Q235B steel of a single material often cannot meet the requirements.

[0004] Combining tin-phosphorus bronze with Q235B steel to create a composite material is an ideal solution for achieving complementary performance and cost advantages. Theoretically, this composite material can combine the excellent high strength and wear resistance of tin-phosphorus bronze with the low cost of Q235B steel, thus significantly broadening the material's application scenarios. However, due to significant differences in melting point, coefficient of thermal expansion, and other physical properties between tin-phosphorus bronze and Q235B steel, conventional rolling composite methods can lead to poor weld quality and difficulty in forming an effective metallurgical bonding interface, severely affecting the reliability of the composite interface and the final performance of the product.

[0005] Explosive welding technology can theoretically achieve such dissimilar metal composites; however, its process effectiveness depends on empirical parameter adjustments for specific material combinations. Currently, there are no reports on explosive welding composites of tin-phosphor bronze and Q235B steel, and the exploration of processes and parameter optimization is still in its infancy, lacking mature practical solutions and publicly available technical reports.

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a large-size tin-phosphor bronze / Q235B composite plate and its preparation method, so as to solve the key problems of poor interfacial bonding quality and immature process faced in the preparation of this composite material. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the first objective of this invention is to provide a method for preparing large-size tin-phosphor bronze / Q235B composite plates. This invention employs an explosive welding process to achieve interfacial metallurgical bonding between large-size tin-phosphor bronze and Q235B steel composite plates. The resulting composite plate combines the high strength and high wear resistance of tin-phosphor bronze with the low-cost advantages of Q235B steel.

[0008] The second objective of this invention is to provide a large-size tin-phosphor bronze / Q235B composite plate prepared by the above-described preparation method.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] This invention discloses a method for preparing a large-size tin-phosphor bronze / Q235B composite plate, which involves explosively bonding a tin-phosphor bronze plate with a Q235B steel plate to obtain the tin-phosphor bronze / Q235B composite plate.

[0011] During the explosive bonding process, support columns are uniformly arranged in a rectangular array between the tin-phosphor bronze plate and the Q235B steel plate, with a total number of 24 to 40 support columns.

[0012] During the explosive recombination, a layer of sawdust is evenly laid on the explosive layer as an inert layer;

[0013] During the explosive reaction, the composition of the explosive used, by mass percentage, is as follows: rock-expanded ammonium nitrate explosive: 70% ~ 80%, calcium carbonate: 8% ~ 15%, perlite powder: 8% ~ 12%, diatomaceous earth: 2% ~ 5%, the detonation velocity of the explosive is 2100 ~ 2300 m / s, and the saturation is 7 ~ 8 mm.

[0014] This invention employs an explosive bonding method. By using the aforementioned low-velocity and low-charge explosives, the cross-sectional waveform can be effectively controlled, avoiding excessively large interface waveforms and the formation of numerous vortices. This ensures a uniform, small-wave interface. Furthermore, the arrangement of support columns ensures the uniformity and stability of the cladding plate's flight attitude during the explosive welding process. Simultaneously, the uniform application of a layer of coarse wood chips as an inert layer on the explosive layer can compensate for potential density inconsistencies or detonation wave disturbances, resulting in more uniform stress on the cladding plate. This effectively reduces localized unbonded or over-melted areas, thereby creating a high-quality composite interface with high bonding strength and high bonding rate between the large-size tin-phosphor bronze and Q235B steel composite plates.

[0015] The low-detonation-velocity rock-expanded ammonium nitrate explosive configured in this invention is improved by adding inert materials and sensitizers to the existing rock-expanded ammonium nitrate explosive. This invention effectively reduces the charge density and energy density per unit volume of the explosive by adding appropriate amounts of inert materials such as calcium carbonate and diatomaceous earth. Although calcium carbonate and diatomaceous earth are both inert materials, they play a crucial synergistic role in the low-detonation-velocity explosive system of this invention: calcium carbonate, through high-temperature endothermic decomposition, reduces the detonation velocity and intensity of the explosive; diatomaceous earth, due to its physical structure, stabilizes the expanded explosive, ensuring stable initiation and detonation wave propagation. Excessive calcium carbonate content leads to an excessively low detonation velocity, failing to drive effective bonding of the plates; insufficient calcium carbonate content results in excessively violent detonation, easily causing interface melting and reducing the plate bonding rate. Insufficient diatomaceous earth content reduces detonation wave stability and affects the plate bonding rate; excessive diatomaceous earth content affects the energy density per unit volume of the explosive, weakening the driving energy after detonation. Simultaneously, the addition of an appropriate amount of perlite powder, with its porous structure, compensates for the potential decrease in initiation sensitivity caused by excessive dilution, ensuring the possibility of reliable initiation using industrial detonators. The synergistic use of these two inert materials with rock-expanded ammonium nitrate explosive and perlite powder achieves an optimal balance between detonation velocity, saturation, and safety, while ensuring necessary initiation reliability. It is particularly suitable for the explosive welding of tin-phosphor bronze and steel. The selection of low-velocity explosives enables the formation of a stable and controllable metal jet, reducing damage to the base plate. It effectively controls the cross-sectional waveform, avoiding excessively large interface waveforms and the formation of numerous vortices, ensuring a uniform, small-wave interface and achieving a good wavy bonding interface, making it more suitable for the explosive bonding of large-size plates.

[0016] In a preferred embodiment, the tin-phosphor bronze plate is of type QSn6.5-0.1, and the Q235B steel plate is a commercially available hot-rolled plate. In this invention, the selected QSn6.5-0.1 tin-phosphor bronze in its M-state (soft state) already possesses excellent plasticity and formability, and its properties meet subsequent processing requirements. The Q235B steel plate, being a commercially available hot-rolled plate, also possesses good plasticity; neither requires heat treatment to meet processing needs.

[0017] In actual operation, commercially available tin-phosphor bronze coils are flattened to obtain tin-phosphor bronze plates. The tin-phosphor bronze plates and Q235B steel plates are then cut to the required dimensions, and the surfaces are cleaned and polished to remove oxide layers and oil stains, ensuring that the surface roughness of the plates is ≤3μm.

[0018] In a preferred embodiment, the roughness of both the tin-phosphor bronze plate and the Q235B steel plate is ≤3μm.

[0019] In a preferred embodiment, the Q235B steel plate is used as the base plate, and the tin-phosphor bronze plate is used as the cladding plate, wherein the length and width of the tin-phosphor bronze plate are both greater than the length and width of the Q235B steel plate.

[0020] By using the lower-cost Q235B steel plate as the base plate and the higher-cost tin phosphor bronze plate as the cladding plate, and by controlling the length and width of the tin phosphor bronze plate to be slightly larger than the Q235B steel plate used as the base plate, the quality of the welding interface can be better ensured, and allowance can be reserved for subsequent finishing.

[0021] In a further preferred embodiment, the length × width × thickness of the Q235B steel plate is (2000~3000)mm × (1500~2500)mm × (14~30)mm; and the length × width × thickness of the tin phosphor bronze plate is (2050~3050)mm × (1540~2540)mm × (3~6)mm.

[0022] In this invention, the Q235B steel plate can be selected according to the thickness of the plate required for industrial applications, while the thickness of the tin-phosphor bronze plate layer is controlled within the range of this invention, which can effectively control costs and ensure excellent wear resistance.

[0023] In a preferred embodiment, support columns are uniformly arranged in a rectangular array of M rows × N columns between the tin-phosphor bronze plate and the Q235B steel plate, where M is 5~8 and N is 4~6.

[0024] In this invention, the spacing of the support columns is kept equal or approximately equal in both the length and width directions to ensure the uniformity and stability of the flight attitude of the cladding plate during the explosive welding process, thereby obtaining a large-area composite plate with consistent interface bonding quality. Through the above arrangement, after the tin-phosphor bronze plate is laid, a uniform and parallel initial installation gap can be formed between it and the Q235B steel plate, effectively preventing the sagging of the middle area caused by the weight of the cladding plate and the explosive.

[0025] In a preferred embodiment, the diameter of the support column is 8-10 mm and the height is 4-8 mm. The height of the support column is the optimal spacing for explosive welding.

[0026] In a preferred embodiment, the thickness of the explosive layer is 25-50 mm. Experiments have shown that by utilizing the explosive properties of the present invention, in conjunction with the thickness of the explosive layer, the wavelength and amplitude of the wave can be effectively adjusted, resulting in optimal interfacial bonding performance of the composite material. If the explosive layer is too thin (<25 mm), the collision velocity is lower than the critical value for forming the interface between the jet and the wave, leading to a large area of ​​the material not being composited or the interface being flat. If it is too thick (>50 mm), the collision point velocity will be too high, causing excessive melting of the interface, reducing the bonding strength, and the cost will be too high.

[0027] In a preferred embodiment, the thickness of the inert layer is 1 to 1.5 times the thickness of the explosive layer.

[0028] The inert layer can compensate for potential density unevenness or detonation wave disturbances in the explosive layer, making the stress on the cladding plate more uniform and effectively reducing local unbonded or over-melted areas. It also prevents impurities such as sand from mixing into the explosive layer, reducing accidental damage to the explosive layer during operation.

[0029] In a preferred embodiment, the average particle size of the wood chips is 3mm to 10mm, and the mass of wood chips with a particle size of less than 1mm is less than 5% of the total mass of the wood chips.

[0030] In actual operation, dry, loose, and non-clumped coarse sawdust is required. In this invention, the coarse sawdust consists of irregular particles with an average particle size between 3.0 mm and 10.0 mm, of which the content of fine sawdust with a particle size less than 1.0 mm should be less than 5% (mass fraction). Coarse sawdust is chosen over fine sawdust because fine sawdust is easily compacted and does not provide a buffering effect. The sufficient porosity of coarse sawdust prevents it from being compacted instantly by the explosion, thus providing a buffering effect. During the explosion, the process of the high-pressure gas pushing the sawdust apart absorbs and disperses the impact force, making the pressure acting on the cladding plate more gradual and sustained, thereby more effectively converting the explosive energy into the collision kinetic energy of the cladding plate. If the sawdust layer is too thin, there is no buffering effect; if it is too thick, the sawdust itself will consume too much explosive energy, which will weaken the pushing force on the cladding plate.

[0031] In a preferred embodiment, the explosive bonding process is as follows: on sandy soil, from bottom to top, a wooden mat, a Q235B steel plate, a support column, a tin-phosphor bronze plate, a protective layer, a fencing structure, an explosive layer, and wood chips are laid out in sequence. Then, a detonator is placed at one short side of the explosive layer, and a connecting wire is used to connect the detonator to the detonator. The detonator is used to detonate the explosive, thus achieving the explosive bonding of the tin-phosphor bronze plate and the Q235B steel plate.

[0032] In industrial applications, a flat and firm sandy area must first be selected as the blasting site. After clearing, a wooden board is placed as a base, with both its length and width exceeding those of the Q235B steel plate. The Q235B steel plate is then placed horizontally in the center of the base. Next, from bottom to top, the following layers are laid on the blasting site: wooden base, Q235B steel plate, support column, tin-phosphor bronze plate, protective layer, enclosure structure, explosive layer, and inert layer. Subsequently, the explosive is detonated, causing the tin-phosphor bronze plate and the Q235B steel plate to collide at high speed, achieving metallurgical bonding and obtaining the required large-size tin-phosphor bronze / Q235B composite plate.

[0033] Further optimization involves ensuring that the centerline of the tin-phosphor bronze plate coincides with that of the Q235B steel plate and that all sides are parallel when the tin-phosphor bronze plate is laid on the support column.

[0034] In a further preferred embodiment, the protective layer is a rubber sheet. A protective layer is laid on the tin-phosphor bronze plate before the explosive is applied to prevent direct contact between the explosive and the tin-phosphor bronze plate, thus providing a buffering effect. In this invention, because large-size plates need to be prepared, a smoother detonation wave is required. Therefore, an elastic rubber layer is chosen, as its elasticity can absorb some of the impact energy, resulting in a more uniform and gentler pressure distribution on the plate, and thus a more stable propagation of the detonation wave. This is particularly crucial for the preparation of large-size plates: on the one hand, it protects the surface of the tin-phosphor bronze; on the other hand, it ensures a uniform and stable waveform bond at the interface. If the protective layer is insufficiently buffered or fails, it can easily lead to a decline in the bonding quality.

[0035] In a further preferred embodiment, the enclosure structure is composed of vertical wooden planks, and the depth of the enclosure structure is 2.5 to 3 times the thickness of the explosive layer. Before laying the explosive layer, the wooden planks are erected around the perimeter of the protective layer to form an enclosure structure, which is used to constrain the explosive layer and ensure its uniform thickness, prevent the explosive from escaping during laying, and form a stable and uniform detonation wave propagation.

[0036] More preferably, after the enclosure structure is laid, insulating tape is used to adhere and fix it along its inner and outer sides, so that it is tightly connected to the Q235B steel plate and wooden pad below. By adhering and fixing the inner and outer sides of the enclosure structure to the Q235B steel plate and wooden pad below, the enclosure structure is prevented from shifting or tipping over when laying explosives.

[0037] In a further preferred embodiment, a cylindrical mounting hole is vertically drilled on one side of the short side of the explosive layer using a wooden or special explosion-proof tool. The hole is 2 / 3 to 3 / 4 the thickness of the current explosive layer, reaching the lower middle part of the explosive layer. Then, the detonator is inserted entirely into the pre-drilled mounting hole, and the hole is filled with explosive to fix the detonator. Finally, a connecting wire is used to connect the detonator to the detonator.

[0038] In actual operation, it is necessary to ensure that the explosive charge of the detonator is completely buried inside the explosive layer. Then, a small amount of loose explosive is used to gently fill the gaps in the holes to fix the detonator. Finally, the explosive is detonated using an initiator, so that the tin-phosphor bronze plate and the Q235B steel plate collide at high speed and achieve metallurgical bonding, thus obtaining the required large-size tin-phosphor bronze / Q235B composite plate.

[0039] The present invention also provides a large-size tin-phosphor bronze / Q235B composite plate prepared by the above preparation method, wherein the large-size tin-phosphor bronze / Q235B composite plate is composed of a tin-phosphor bronze layer and a Q235B steel layer, and the tin-phosphor bronze layer and the Q235B steel layer have a wave-shaped bonding interface.

[0040] In the preferred embodiment, the interfacial bonding rate between the tin-phosphor bronze layer and the Q235B steel layer in the tin-phosphor bronze / Q235B composite plate is ≥98%, and the interfacial shear strength is ≥274MPa.

[0041] Principles and advantages

[0042] This invention relates to a large-size tin-phosphorus bronze / Q235B composite plate and its preparation method. During explosive welding, process parameters such as the spacing between the base plate and the thickness of the explosive are related to the waveform interface structure and properties of the composite plate. This invention innovatively uses low-detonation-velocity rock-expanded ammonium nitrate explosive, which allows adjustment of the wavelength and amplitude of the wave pattern through process parameters (such as explosive thickness), facilitating the control of the interface waveform. This results in a wave-shaped bonding interface with high bonding strength and high bonding rate, thereby solving the problems of poor interface quality and low bonding strength in conventional composite methods due to the large differences in physical properties between tin-phosphorus bronze and Q235B steel.

[0043] The tin-phosphorus bronze / Q235B composite plate obtained through this explosive welding process retains the high strength and wear resistance of tin-phosphorus bronze while leveraging the low-cost advantage of Q235B steel, thus meeting the requirements of various fields.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] 1. This process combines two metals to obtain a composite plate that combines the high strength and wear resistance of tin phosphor bronze with the low cost of Q235B steel. It can also produce large-size plates in one go, achieving cost reduction and efficiency improvement while meeting the performance requirements, thus satisfying industrial needs.

[0046] 2. The selected tin-phosphor bronze and Q235B base material have excellent plasticity, which ensures that bonding can be achieved without preheating during the explosive welding process without cracking. This not only simplifies the process, but also directly reduces the additional energy, time and equipment costs caused by the heat treatment process, making the entire preparation process more efficient and economical.

[0047] 3. By selecting low-explosion-velocity rock-expanded ammonium nitrate explosive and precisely controlling the process parameters, tin-phosphorus bronze / Q235B composite plates were prepared. This effectively solved the composite problem of the two materials being difficult to dissolve at room temperature and easily oxidized upon heating due to their large differences in physical properties. Thus, it solved the key problem of poor interface quality in conventional composite methods and obtained a high-quality composite interface with high bonding strength and high bonding rate.

[0048] 4. The support columns are arranged in a rectangular array of M rows × N columns, evenly distributed on the upper surface of the Q235B steel plate. The spacing between the columns is equal or approximately equal in both the length and width directions to ensure uniformity and stability during the explosive welding process, thereby obtaining a large-area composite plate with consistent interface bonding quality.

[0049] 5. By laying a layer of dry wood chips as an inert layer above the explosive layer, the transmission of the explosive detonation wave can be optimized, the collision process improved, and the bonding quality enhanced. This inert layer can suppress interface defects caused by longitudinal attenuation and lateral unevenness of explosive energy, thus solving the problem of low bonding rate of large-area composite panels under traditional single-layer explosive arrangement methods, and obtaining high-quality composite panels with continuous interface waveforms and uniform and stable bonding strength. Attached Figure Description

[0050] Figure 1 A schematic diagram of the process structure for explosive welding of tin-phosphor bronze and Q235B steel.

[0051] Figure 2 Sample of explosive welding of tin-phosphorus bronze and Q235B steel.

[0052] Figure 3 Interface morphology of composite panels. Detailed Implementation

[0053] The following are preferred embodiments of the present invention, but not all embodiments. Without departing from the innovative principles of this process, any equivalent process modifications made based on the content of this specification, or direct or indirect applications in other related technical fields, shall be considered within the scope of patent protection of this invention.

[0054] Example 1

[0055] This invention provides a large-size tin-phosphor bronze / Q235B composite plate and its preparation method, comprising the following steps:

[0056] Step 1: Flatten the purchased tin-phosphor bronze coil to obtain tin-phosphor bronze plates. Then, cut the tin-phosphor bronze plates and Q235B steel plates to the required dimensions: Q235B steel plate (length × width × thickness) 2000mm × 1500mm × 15mm; tin-phosphor bronze plates (length × width × thickness) 2050mm × 1550mm × 3mm. Use sanding belt to clean and polish the surface of the plates to remove the oxide layer and oil stains, ensuring a surface roughness ≤3μm.

[0057] Step 2: Prepare low-detonation-velocity rock-expanded ammonium nitrate explosive. The composition of the prepared explosive, by mass percentage, is: rock-expanded ammonium nitrate explosive 75%, calcium carbonate 10%, perlite powder 10%, diatomaceous earth 5%. The detonation velocity of this rock-expanded ammonium nitrate explosive is 2200 m / s, and its saturation is 7.5 mm.

[0058] Step 3: Select a firm sandy ground, first place a wooden pad with dimensions of 2500mm×2000mm×20mm, then place the treated Q235B steel plate horizontally in the center of the pad as the base plate.

[0059] Step 4: Arrange 24 aluminum alloy support columns (Φ10mm×4.0mm) on the surface of the Q235B steel plate, evenly in a rectangular array of 6 rows × 4 columns: in the length direction, the center distance of the first and last row of support columns is 100mm from the short side of the steel plate, and the row spacing is about 360mm; in the width direction, the center distance of the first and last column of support columns is 150mm from the long side of the steel plate, and the column spacing is about 400mm.

[0060] Step 5: Place the tin-phosphor bronze plate, which will serve as the cladding plate, on the support column, ensuring that it is parallel to the four sides of the Q235B steel plate and that the centers of the two plates are aligned. Lay a layer of rubber sheet on the tin-phosphor bronze plate as a protective layer.

[0061] Step 6: Erect wooden boards around the protective layer to form a fence structure, and use high-strength insulating tape to bond the inside and outside of the fence structure to the base plate and pad. At this time, the depth of the fence structure is 90mm.

[0062] Step 7: Spread the low-explosion-velocity rock-expanded ammonium nitrate explosive evenly on the protective layer. After spreading it evenly, use a wooden board to scrape it flat. At this time, the thickness of the explosive layer is 30mm.

[0063] Step 8: Using a wooden tool, vertically drill a hole along one short side of the explosive layer, reaching the lower middle part of the explosive layer, approximately 25mm deep. Insert the entire detonator into this hole, ensuring the explosive charge is completely embedded within the explosive layer. Gently fill the gaps in the hole with a small amount of loose explosive to secure the detonator. Then, place the detonating detonator and connect it to the detonator using a connecting wire.

[0064] Step 9: Evenly pour the prepared dry coarse sawdust with a particle size of 3-8mm above the explosive layer where the detonators have been installed, smooth it out, and ensure that the thickness is 45mm. When laying it, be careful to let the detonator lead wire emerge naturally from the inert layer, and do not pull or bend the lead wire.

[0065] Step 10: After personnel have evacuated to a safe area, detonate the explosive using a detonator. The explosive detonation drives the tin-phosphor bronze plate to collide at high speed with the Q235B steel plate, achieving a metallurgical bond between the two.

[0066] Step 11: Clean and level the surface of the composite plate after explosive welding, and cut off the cracked and collapsed parts at the edges.

[0067] The large-size tin-phosphorus bronze / Q235B steel composite plate prepared in this embodiment, after ultrasonic flaw detection, showed an interface bonding rate of 98.2% and an interface shear strength of 288 MPa.

[0068] Example 2

[0069] This invention provides a large-size tin-phosphor bronze / Q235B composite plate and its preparation method, comprising the following steps:

[0070] Step 1: Flatten the purchased tin-phosphor bronze coil to obtain tin-phosphor bronze plates. Then cut the tin-phosphor bronze plates and Q235B steel plates to the required dimensions. The dimensions of the Q235B steel plate are: 2500mm × 1800mm × 25mm (length × width × thickness); the dimensions of the tin-phosphor bronze plate are: 2550mm × 1850mm × 5mm (length × width × thickness). Use sanding belt to clean and polish the surface of the plates to remove the oxide layer and oil stains, so that the surface roughness of the plates is ≤3μm.

[0071] Step 2: Prepare low-detonation-velocity rock-expanded ammonium nitrate explosive. The composition of the prepared explosive, by mass percentage, is: rock-expanded ammonium nitrate explosive 78%, calcium carbonate 12%, perlite powder 8%, diatomaceous earth 2%. The detonation velocity of this rock-expanded ammonium nitrate explosive is 2250 m / s, and its saturation is 7.8 mm.

[0072] Step 3: Select a firm sandy ground, first place a wooden pad with dimensions of 3000mm×2100mm×30mm, then place the treated Q235B steel plate horizontally in the center of the pad as the base plate.

[0073] Step 4: Arrange 32 aluminum alloy support columns (Φ12mm×5.5mm) on the surface of the Q235B steel plate, in a 7-row × 5-column array, with the central column staggered to optimize support: in the length direction, the center distance of the first and last row of support columns from the short side of the steel plate is 120mm, and the row spacing is approximately 327mm; in the width direction, the center distance of the first and last row of support columns from the long side of the steel plate is 180mm, and the column spacing is approximately 360mm.

[0074] Step 5: Place the tin-phosphor bronze plate, which will serve as the cladding plate, on the support column, ensuring that it is parallel to the four sides of the Q235B steel plate and that the centers of the two plates are aligned. Lay a layer of rubber sheet on the tin-phosphor bronze plate as a protective layer.

[0075] Step 6: Erect wooden boards around the protective layer to form a fence structure, and use high-strength insulating tape to bond the inside and outside of the fence structure to the base plate and pad. At this time, the depth of the fence structure is 100mm.

[0076] Step 7: Spread the low-explosion-velocity rock-expanded ammonium nitrate explosive evenly on the protective layer. After spreading it evenly, use a wooden board to scrape it flat. At this time, the thickness of the explosive layer is 40mm.

[0077] Step 8: Using a wooden tool, vertically drill a hole along one short side of the explosive layer, reaching the lower middle part of the explosive layer, approximately 30mm deep. Insert the entire detonator into this hole, ensuring the explosive charge is completely embedded within the explosive layer. Gently fill the gaps in the hole with a small amount of loose explosive to secure the detonator. Then, place the detonating detonator and connect it to the detonator using a connecting wire.

[0078] Step 9: Evenly pour the prepared dry coarse sawdust with a particle size of 5-9mm above the explosive layer where the detonators have been installed, smooth it out, and ensure that the thickness is 60mm. When laying it, be careful to let the detonator lead wire emerge naturally from the inert layer, and do not pull or bend the lead wire.

[0079] Step 10: After personnel have evacuated to a safe area, detonate the explosive using a detonator. The explosive detonation drives the tin-phosphor bronze plate to collide at high speed with the Q235B steel plate, achieving a metallurgical bond between the two.

[0080] Step 11: Clean and level the surface of the composite plate after explosive welding, and cut off the cracked and collapsed parts at the edges.

[0081] The large-size tin-phosphorus bronze / Q235B steel composite plate prepared in this embodiment, after ultrasonic flaw detection, showed an interface bonding rate of 98.5% and an interface shear strength of 278 MPa.

[0082] Example 3

[0083] This invention provides a large-size tin-phosphor bronze / Q235B composite plate and its preparation method, comprising the following steps:

[0084] Step 1: Flatten the purchased tin-phosphor bronze coil to obtain tin-phosphor bronze plates. Then cut the tin-phosphor bronze plates and Q235B steel plates to the required dimensions. The dimensions of the Q235B steel plate are 3000mm × 2000mm × 30mm (length × width × thickness); the dimensions of the tin-phosphor bronze plate are 3050mm × 2050mm × 6mm (length × width × thickness). Use sanding belt to clean and polish the surface of the plates to remove the oxide layer and oil stains, so that the surface roughness of the plates is ≤3μm.

[0085] Step 2: Prepare low-detonation-velocity rock-expanded ammonium nitrate explosive. The composition of the prepared explosive, by mass percentage, is: rock-expanded ammonium nitrate explosive 72%, calcium carbonate 13%, perlite powder 10%, diatomaceous earth 5%. The detonation velocity of this rock-expanded ammonium nitrate explosive is 2180 m / s, and its saturation is 7.2 mm.

[0086] Step 3: Select a firm sandy ground, first place a wooden pad with dimensions of 3500mm×2500mm×40mm, then place the prepared Q235B steel plate horizontally in the center of the pad as the base plate.

[0087] Step 4: Arrange 40 aluminum alloy cylindrical support columns (Φ12mm×6.0mm) on the surface of the Q235B steel plate. They should be evenly arranged in a rectangular array of 8 rows × 5 columns: along the length, the center distance from the first and last row of support columns to the short side of the steel plate is 150mm, and the row spacing is approximately 343mm; along the width, the center distance from the first and last column of support columns to the long side of the steel plate is 200mm, and the column spacing is approximately 400mm.

[0088] Step 5: Place the tin-phosphor bronze plate, which will serve as the cladding plate, on the support column, ensuring that it is parallel to the four sides of the Q235B steel plate and that the centers of the two plates are aligned. Lay a layer of rubber sheet on the tin-phosphor bronze plate as a protective layer.

[0089] Step 6: Erect wooden boards around the protective layer to build a fence structure, and firmly bond the inside and outside of the fence to the base plate and pad with high-strength insulating tape. At this time, the depth of the fence structure is 125mm.

[0090] Step 7: Spread the low-explosion-velocity rock-expanded ammonium nitrate explosive evenly on the protective layer. After spreading it evenly, use a wooden board to scrape it flat. At this time, the thickness of the explosive layer is 50mm.

[0091] Step 8: Using a wooden tool, vertically drill a hole along one short side of the explosive layer, reaching the lower middle part of the explosive layer, approximately 40mm deep. Insert the entire detonator into this hole, ensuring the explosive charge is completely embedded within the explosive layer. Gently fill the gaps in the hole with a small amount of loose explosive to secure the detonator. Then, place the detonating detonator and connect it to the detonator using a connecting wire.

[0092] Step 9: On top of the explosive layer with the detonators installed, evenly pour in the prepared dry coarse sawdust with a particle size of 6-10mm, smooth it out, and ensure that the thickness is 75mm. When laying it, be careful to let the detonator lead wire emerge naturally from the inert layer, and do not pull or bend the lead wire.

[0093] Step 10: After personnel have evacuated to a safe area, detonate the explosive using a detonator. The explosive detonation drives the tin-phosphor bronze plate to collide at high speed with the Q235B steel plate, achieving a metallurgical bond between the two.

[0094] Step 11: Clean and level the surface of the composite plate after explosive welding, and cut off the cracked and collapsed parts at the edges.

[0095] The large-size tin-phosphorus bronze / Q235B steel composite plate prepared in this embodiment, after ultrasonic flaw detection, showed an interface bonding rate of 98.1% and an interface shear strength of 280 MPa.

[0096] Comparative Example 1

[0097] The only difference between this comparative example and Example 1 is the explosive used in step 2; all other steps and parameters are exactly the same as in Example 1.

[0098] Step 2: Select rock-expanded ammonium nitrate explosive with a detonation velocity of 2800~3200 m / s and a saturation of 11~13 mm.

[0099] Steps 3 to 8 are the same as in Example 1.

[0100] The interfacial bonding rate of the tin-phosphorus bronze and Q235B steel explosively welded composite plate prepared by this process was only 72.3%, and the tin-phosphorus bronze plate showed large-area tearing at the detonation end. The use of ordinary high-velocity, high-charge ammonium nitrate explosive resulted in excessively strong impact loads, leading to tearing of the composite plate.

[0101] Comparative Example 2

[0102] The only difference between this comparative example and Example 1 is the arrangement of the support columns in step 4; all other steps and parameters are exactly the same as in Example 1.

[0103] Step 4: Place an identical aluminum alloy cylinder (Φ10mm×5.0mm) at each of the four corners of the Q235B steel plate, for a total of only 4 support columns.

[0104] Steps 5 to 8 are the same as in Example 1.

[0105] The interfacial bonding rate of the tin-phosphorus bronze and Q235B steel explosively welded composite plate prepared by this process was only 64.8%. The unbonded area was distributed in large patches in the center and long side areas of the plate, and the composite plate as a whole was severely deformed. Under its own weight and explosive load, the middle of the tin-phosphorus bronze plate sagged severely, resulting in extremely uneven distribution of the collision angle and collision velocity on the plate surface during explosive welding. The central area lacked energy and could not form an effective bond.

[0106] Comparative Example 3

[0107] The only difference between this comparative example and Example 1 is the absence of the inert layer in step 9; all other steps and parameters are exactly the same as in Example 1.

[0108] The interfacial bonding rate of the tin-phosphorus bronze and Q235B steel explosively welded composite plate prepared by this process is only 75.9%, indicating slightly poor bonding quality. Furthermore, the bonding quality is poor in areas of the composite plate far from the detonation point, resulting in questionable waveform quality. The lack of an inert layer leads to insufficient energy in the detonation wave as it propagates to distant locations, resulting in localized unbonded areas.

Claims

1. A method for preparing a large-size tin-phosphor bronze / Q235B composite plate, characterized in that: Explosive bonding of tin-phosphor bronze plate with Q235B steel plate yields tin-phosphor bronze / Q235B composite plate. The length × width × thickness of the Q235B steel plate is (2000~3000)mm × (1500~2500)mm × (14~30)mm; The length × width × thickness of the tin phosphor bronze plate is (2050~3050)mm × (1540~2540)mm × (3~6)mm; During the explosive bonding process, support columns are uniformly arranged in a rectangular array between the tin-phosphor bronze plate and the Q235B steel plate, with a total number of 24 to 40 support columns. During the explosive recombination, a layer of sawdust is evenly laid on the explosive layer as an inert layer; The thickness of the explosive layer is 25~50mm; The thickness of the inert layer is 1 to 1.5 times the thickness of the explosive layer; The average particle size of the wood chips is 3mm to 10mm, and the mass of wood chips with a particle size of less than 1mm is less than 5% of the total mass of the wood chips; During the explosive reaction, the composition of the explosive used, by mass percentage, is as follows: rock-expanded ammonium nitrate explosive: 70%~80%, calcium carbonate: 8%~15%, perlite powder: 8%~12%, diatomaceous earth: 2%~5%; the detonation velocity of the explosive is 2100~2300m / s, and the saturation is 7~8 mm.

2. The method for preparing a large-size tin-phosphor bronze / Q235B composite plate according to claim 1, characterized in that: The tin-phosphor bronze plate is of type QSn6.5-0.1, and the Q235B steel plate is a commercially available hot-rolled plate; The roughness of both the tin-phosphor bronze plate and the Q235B steel plate is ≤3μm; The Q235B steel plate is used as the base plate, and the tin-phosphor bronze plate is used as the cover plate, with the length and width of the tin-phosphor bronze plate being greater than those of the Q235B steel plate.

3. The method for preparing a large-size tin-phosphor bronze / Q235B composite plate according to claim 1, characterized in that: Support columns are evenly arranged in a rectangular array of M rows × N columns between the tin-phosphor bronze plate and the Q235B steel plate, where M is 5~8 and N is 4~6. The diameter of the support column is 8~10mm and the height is 4~8mm.

4. The method for preparing a large-size tin-phosphor bronze / Q235B composite plate according to claim 1, characterized in that: The explosive bonding process is as follows: On sandy soil, from bottom to top, a wooden mat, a Q235B steel plate, a support column, a tin-phosphor bronze plate, a protective layer, a enclosure structure, an explosive layer, and wood chips are laid out in sequence. Then, a detonator is placed at one of the short sides of the explosive layer. The detonator is connected to the detonator with a connecting wire. The detonator is used to ignite the explosive, thus achieving the explosive bonding of the tin-phosphor bronze plate and the Q235B steel plate.

5. The method for preparing a large-size tin-phosphor bronze / Q235B composite plate according to claim 4, characterized in that: When laying the tin-phosphor bronze plate on the support column, it is necessary to ensure that the center line of the tin-phosphor bronze plate coincides with that of the Q235B steel plate and that all sides are parallel. The protective layer is a rubber sheet; The enclosure structure is made of vertical wooden boards, and the depth of the enclosure structure is 2.5 to 3 times the thickness of the explosive layer.

6. The method for preparing a large-size tin-phosphor bronze / Q235B composite plate according to claim 4, characterized in that: After the fencing structure is laid, use insulating tape to bond and fix it along its inner and outer sides, so that it is tightly connected to the Q235B steel plate and wooden pad below.

7. The method for preparing a large-size tin-phosphor bronze / Q235B composite plate according to claim 4, characterized in that: Using a wooden or special explosion-proof tool, vertically drill a cylindrical mounting hole on one side of the short side of the explosive layer. The hole should be 2 / 3 to 3 / 4 the thickness of the current explosive layer, reaching the lower middle part of the explosive layer. Then, insert the entire detonator into the pre-drilled mounting hole, fill the hole with explosive, fix the detonator, and then connect the detonator to the detonator with a connecting wire.

8. The large-size tin-phosphor bronze / Q235B composite plate prepared by the preparation method according to any one of claims 1-7, characterized in that: The large-size tin-phosphor bronze / Q235B composite plate is composed of a tin-phosphor bronze layer and a Q235B steel layer, and there is a corrugated bonding interface between the tin-phosphor bronze layer and the Q235B steel layer. In the tin-phosphor bronze / Q235B composite plate, the interfacial bonding rate between the tin-phosphor bronze layer and the Q235B steel layer is ≥98%, and the interfacial shear strength is ≥274MPa.

Images