Silver-steel composite plate explosive welding composite method

Abstract

The invention relates to the technical field of explosive welding methods for composite plates, in particular to an explosive welding compounding method for a silver-steel composite plate. The method comprises the following steps that firstly, the surfaces of a silver plate and a steel plate are subjected to polishing treatment and film pasting protection; 2, a novel explosive is adopted, and explosive parameters are determined, specifically, the detonation velocity ranges from 1700 m / s to 1800 m / s, the brisance ranges from 6.5 mm to 6.8 mm, and the unit dosage ranges from 12 kg / m < 2 > to 15 kg / m < 2 >; and the optimal explosive welding distance is determined, wherein the height of the distance between the silver plate and the steel plate is 4-8 mm. According to the prepared silver-steel composite plate, effective metallurgical bonding of the silver plate and the steel plate is achieved, the bonding strength is far higher than that of other composite methods such as explosive welding, the defects of breakdown, wrinkling, tearing, jet flow accumulation and the like generated by a conventional welding method are effectively overcome, and meanwhile the phenomenon that the mechanical property does not reach the standard is avoided. Compared with other composite methods, the explosive welding process has the advantages that common calcium carbonate and bran are added and mixed with the explosive, low detonation velocity and appropriate brisance are obtained, the content of the explosive is reduced, and the cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of composite plate explosion welding methods, in particular to a silver-steel composite plate explosion welding composite method. Background Art

[0002] At present, driven by the growth of photovoltaic market demand and the demand of semiconductor industry, the demand of polysilicon market is gradually increasing. Polysilicon is mainly used as the raw material of semiconductors and is the main raw material for making single crystal silicon. It can be used to make various transistors, rectifier diodes, thyristors, solar cells, integrated circuits, electronic computer chips and infrared detectors. It is the most important and basic functional material for the semiconductor industry, electronic information industry and solar photovoltaic cell industry. At present, the reduction furnace material for producing polysilicon is mainly austenitic stainless steel. The energy consumption of preparing polysilicon with this material is high and the quality of polysilicon is not high. Using pure silver equipment is too expensive.

[0003] Therefore, the use of silver-steel composite plates can not only reduce energy consumption, but also ensure the quality of polysilicon, and also reduce manufacturing costs. In order to produce silver-steel composite plates, an explosive welding method is required. There are many methods for producing silver-steel composite plates by explosive welding. It is common that the silver-steel composite plates have small widths, and the surfaces of large widths have some unevenness, rough corrugations, wrinkles and other defects, which require subsequent processing. These surface quality problems may affect the appearance and performance of the composite plates in the later stage. Summary of the invention

[0004] The object of the present invention is to provide a silver-steel composite plate explosive welding composite method to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides a silver-steel composite plate explosive welding composite method, comprising the following steps:

[0006] Step 1: Select silver plates and steel plates with a width of 2-10m and a length of 2-4m, use a pulsed automatic argon arc welding machine to splice the silver plates, polish the surfaces of the silver plates and steel plates to be joined, remove impurities such as oil and rust, ensure the surface is smooth, and the roughness of the surfaces to be joined is between 2-3um;

[0007] In order to prevent the high temperature and explosion products generated by the explosion of explosives from burning and damaging the surface of the silver plate, the non-to-be-bonded surface of the silver plate (the reverse side of the to-be-bonded surface) is protected by a polyethylene film with a thickness of not less than 0.5mm.

[0008] Step 2: Determine the type of explosive: Use a new type of explosive, which is a stable low-detonation-velocity explosive prepared by adding calcium carbonate and bran as diluents to powdered industrial explosives, wherein bran accounts for 2-7% of the total amount and calcium carbonate accounts for 54-69% of the total amount;

[0009] Determine the explosive parameters: detonation velocity is 1700-1800m / s, intensity is 6.5-6.8mm, unit dosage is 12-15kg / m 2 ;

[0010] Determine the best explosion welding distance: that is, the distance between the silver plate and the steel plate. The height between the silver plate and the steel plate is 4-8mm (the height is determined according to the thickness of the silver plate);

[0011] Step 3: Place the steel plate on a flat foundation; the support between the silver plate and the steel plate is made of the same material as the silver plate. After arranging the support on the steel plate, place the silver plate on the support;

[0012] Ensure that the support between the silver plate and the steel plate is intact after placement; install explosives on the silver plate. The thickness of the explosives is determined according to the thickness of the silver plate, and the thickness of the explosives is 30-40mm; and detonate at the center of the silver plate (it can be detonated at the corner or edge when the plate width is small); the instantaneous high pressure and high temperature generated by the explosion cause the silver plate and the steel plate to collide at high speed in a very short time to achieve metallurgical bonding;

[0013] Step 4: Clean the silver steel composite plate after explosion welding to remove residual explosives and impurities on the surface;

[0014] After the explosion composite is completed, the silver steel composite plate is subjected to ultrasonic testing to determine the composite grade. The ultrasonic testing is used to determine that it meets the "NB / T47013.3-2023 Grade I" standard. After the ultrasonic testing is completed, heat treatment is performed to eliminate welding stress and improve the mechanical properties and stability of the composite plate.

[0015] After the heat treatment is completed, the plate is leveled to ensure that the unevenness of the entire plate surface meets the standard requirements. After the leveling is completed, a second ultrasonic flaw detection is performed to confirm that the bonding rate of the entire plate surface reaches 100%.

[0016] In the prior art, the key to the success of explosive welding of silver-steel composite plates lies in the lower explosive detonation velocity and appropriate intensity. The lower detonation velocity can ensure that defects such as jet accumulation, tearing, breakdown, and wrinkles are reduced or avoided during the explosive welding process; due to the lower detonation velocity, the intensity of the mixed explosive will also decrease accordingly. Only with the appropriate intensity can the bonding strength after explosive welding be increased, which is the main technical difficulty in the welding of silver-steel composite plates. The explosives produced by the explosives factory generally have a detonation velocity of 3300m / s and an intensity of about 13mm, or even higher. However, it is difficult to reduce the detonation velocity of the explosives to 1700-1800m / s with the intensity still being controlled at 6.5-6.8mm with the existing technology. In the present invention, calcium carbonate and bran are added to the powdered industrial explosives to reduce the detonation velocity of the explosives while ensuring the intensity of the explosives, and the content of the explosives is also reduced accordingly. Among them, calcium carbonate is obtained by crushing stones, and bran is a product of rice husking. As an additive, it has a wide source and is inexpensive. The new explosive prepared in this way greatly reduces the production cost and ensures the quality of the product after explosive welding.

[0017] Secondly, by accurately adjusting the distance between the silver plate and the steel plate, and strictly controlling the amount of explosives used per unit area according to the different thickness of the silver plate, the surface defects such as surface perforation, cracks, and wrinkles generated during the explosion welding of large-plate silver-steel composite plates were solved, and high-quality silver-steel composite plates were obtained, which reduced the subsequent surface processing costs and avoided the risks of later use, thereby ensuring product quality.

[0018] As a further improvement of the technical solution, in the step 2, the powdered industrial explosive is preferably an ammonium nitrate-based industrial explosive, which is a mixture of ammonium nitrate and an oil phase material.

[0019] As a further improvement of the technical solution, in step 4, the heat treatment temperature is 650° C. and the heat preservation is performed for 4 hours.

[0020] As a further improvement of the present technical solution, in the step 4, the leveling process is performed using a leveling machine.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] In the composite method of explosion welding of silver-steel composite plate, the silver-steel composite plate is obtained by explosion welding through this process, so that the silver plate and the steel plate can achieve effective metallurgical bonding, and the bonding strength is much higher than other composite methods such as explosion welding, which effectively solves the defects such as breakdown, wrinkles, tearing, jet accumulation, etc. caused by conventional welding methods, and also solves the phenomenon of substandard mechanical properties. Compared with other composite methods, this explosion welding process adopts the addition of common calcium carbonate and bran, and by mixing with explosives, the low detonation velocity and appropriate intensity are obtained, the explosive content is reduced, and the cost is relatively low. It can be all done manually, and the requirements for the field site are not high, and complex equipment, tooling and process conditions are not required. The silver-steel composite plate obtained by this scheme after explosion welding has excellent surface quality and meets the requirements of relevant standards. It can be applied to the composite of silver plates and steel plates of different thicknesses and sizes to meet the needs of different fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the explosion welding structure of an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0025] according to Figure 1 As shown, the embodiment of the present invention provides a silver-steel composite plate explosion welding composite method, and the specific steps are as follows:

[0026] Step 1. Select silver plates and steel plates with a width of 2-10m and a length of 2-4m. Due to the limitation of the width of the silver plate, it needs to be spliced ​​when the silver plate width is large. Use a pulse automatic argon arc welding machine to splice the silver plates. During the splicing process, in order to ensure the quality of the silver plate weld, it is necessary to ensure that the welding site is clean and pay attention to gas protection;

[0027] Polish the surfaces of the silver plate and steel plate to be bonded to remove impurities such as oil, rust, etc. to ensure a smooth surface. The roughness of the bonding surface is between 2-3um;

[0028] Conduct penetration and radiographic testing on the silver plate welds to ensure that they meet the requirements of NB / T47013.5-2015 Grade I and NB / T47013.2-2015 Grade AB;

[0029] In order to prevent the high temperature and explosion products generated by the explosion of explosives from burning and damaging the surface of the silver plate, the non-to-be-bonded surface of the silver plate (the reverse side of the to-be-bonded surface) is protected by a film. The conventional method is to apply ink on the non-bonded surface of the silver plate for protection, but the effect is not ideal. Therefore, this embodiment uses a polyethylene film for film protection, and the film thickness is not less than 0.5 mm. When the film is applied, no pores, wrinkles, etc. appear at the film.

[0030] Step 2: Determine the appropriate explosive type, dosage, explosion speed and other parameters through theoretical calculation and experimental verification. The selection of these parameters should take into account factors such as the material, thickness, and bonding strength requirements of the silver plate and steel plate.

[0031] Determine the type of explosive: This solution provides a new type of explosive, which is a stable low-detonation-velocity explosive prepared by adding calcium carbonate and bran as diluents to powdered industrial explosives, wherein bran accounts for 2-7% of the total amount, and calcium carbonate accounts for 54-69% of the total amount. The powdered industrial explosive preferably uses ammonium nitrate-based industrial explosives, which are mixed with ammonium nitrate and an oil phase material (commonly used diesel). The powdered industrial explosive is a prior art and this embodiment will not be described in detail. Specifically, calcium carbonate is obtained by crushing stones, and bran is a rice hulling product. The purpose is to obtain a low detonation velocity and a suitable intensity by mixing with the powdered industrial explosive, thereby reducing the explosive content, reducing the cost, and being able to be operated manually. It does not require high field sites and does not require complex equipment, tooling, and process conditions.

[0032] Determine the explosive parameters: detonation velocity is 1700-1800m / s, intensity is 6.5-6.8mm, unit dosage is 12-15kg / m 2 ;

[0033] Determine the best explosion welding spacing, that is, the distance between the silver plate and the steel plate. Too large or too small a spacing may cause defects such as breakdown, wrinkles, and tears on the silver plate surface; through calculation and experimental verification, the height of the spacing between the silver plate and the steel plate is determined to be 4-8mm (the spacing height is determined according to the thickness of the silver plate), refer to Figure 1 shown.

[0034] Step 3: Place the steel plate on a flat foundation according to the predetermined position to ensure that the gap between the two is uniform; the spacing support between the silver plate and the steel plate is made of silver sheets of the same material as the silver plate. After arranging the support on the steel plate, place the silver plate on the support;

[0035] Ensure that the supports between the silver plate and the steel plate are intact after placement; install explosives on the silver plate. The thickness of the explosives is determined according to the thickness of the silver plate, and the thickness of the explosives is 30-40mm; and detonate at the center of the silver plate (it can be detonated at the corner or edge when the plate width is small); the instantaneous high pressure and high temperature generated by the explosion cause the silver plate and the steel plate to collide at high speed in a very short time to achieve metallurgical bonding.

[0036] Step 4: Clean the silver-steel composite plate after explosion welding to remove residual explosives and impurities on the surface, and protect the surface of the silver-steel composite plate during lifting and transportation;

[0037] After the explosion composite is completed, the silver steel composite plate is subjected to ultrasonic testing to determine the composite grade. The ultrasonic testing is used to determine that it meets the "NB / T47013.3-2023 Grade I" standard. After the ultrasonic testing is completed, heat treatment (650℃, insulation for 4h) is carried out to eliminate welding stress and improve the mechanical properties and stability of the composite plate.

[0038] After the heat treatment is completed, a leveling machine is used to level the board so that the unevenness of the entire board surface meets the standard requirements; after the leveling is completed, a second ultrasonic flaw detection is carried out to confirm that the bonding rate of the entire board surface reaches 100% again;

[0039] According to the required size, the composite board is mechanically processed, such as cutting, drilling, milling, etc., to meet different application requirements. At the same time, samples are taken for sample processing and mechanical property experiments. The shear value is ≥100MPa, and the bending and stretching are in line with the standards. Taking Ag99.99+S31603(2.4+24) composite as an example, the mechanical property comparison is shown in Table 1:

[0040] Table 1

[0041]

[0042]

[0043] According to Table 1, the shear strength of the explosively welded silver-steel composite plate obtained by the method of the present invention reaches 187MPa, which is much higher than the standard value of 140MPa, while the shear value obtained by the conventional method is 89MPa, which does not meet the standard requirements. This shows that the present solution has significantly improved the welding quality and enhanced the bonding strength of the composite plate.

[0044] Secondly, although the method of the present invention has made improvements on the explosive welding method, the yield strength and tensile strength of the composite plate are still maintained within the qualified range, which is equivalent to the conventional method, indicating that the improved method does not have a negative impact on these mechanical properties of the composite plate.

[0045] At the same time, the elongation of the explosion-welded silver-steel composite plate obtained by the method of the present invention is 33.5%, which is higher than the 30.5% of the conventional method, indicating that the plasticity of the composite plate has been improved, which is more conducive to bearing deformation in certain applications. In the internal and external bending test, the composite plate of the method of the present invention did not show interface delamination, while the conventional method failed, which shows that the scheme improves the interface bonding quality of the composite plate, making it more reliable when bearing bending.

[0046] In summary, the present invention improves the explosive welding method, not only ensuring the basic mechanical properties of the composite plate, but also improving the shear strength, elongation and bending performance, making the composite plate superior to the prior art in comprehensive mechanical properties; by improving the shear strength and bending performance of the silver-steel composite plate, its comprehensive mechanical properties are improved, thereby improving the reliability and application range of the product. These improvements have important practical significance for the performance of the composite plate in engineering applications.

[0047] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A silver-steel composite plate explosive welding composite method, characterized in that: The following steps are involved: Step 1: Select silver plates and steel plates with a width of 2-10m and a length of 2-4m, use a pulsed automatic argon arc welding machine to splice the silver plates, and polish the surfaces of the silver plates and steel plates to be joined; After polishing, apply protective film to the non-joining surface of the silver plate; Step 2: Determine the type of explosive: Use a new type of explosive, which is a stable low-detonation-velocity explosive prepared by adding calcium carbonate and bran as diluents to powdered industrial explosives, wherein bran accounts for 2-7% of the total amount and calcium carbonate accounts for 54-69% of the total amount; Determine the explosive parameters: detonation velocity is 1700-1800m / s, intensity is 6.5-6.8mm, unit dosage is 12-15kg / m 2 ; Determine the best explosion welding distance: the height between the silver plate and the steel plate is 4-8mm; Step 3: Place the steel plate on the leveled foundation; the spacing support between the silver plate and the steel plate is made of the same material as the silver plate. After arranging the support on the steel plate, place the silver plate on the support; Install explosives on the silver plate with a thickness of 30-40mm and detonate at the center or corner of the silver plate. The instantaneous high pressure and high temperature generated by the explosion cause the silver plate and the steel plate to collide at high speed in a very short time to achieve metallurgical bonding. Step 4: Clean the silver steel composite plate after explosion welding to remove residual explosives and impurities on the surface; After the explosion-compounded silver-steel composite plate is subjected to ultrasonic flaw detection, heat treatment is performed to eliminate welding stress; After the heat treatment is completed, the plate is leveled to ensure that the unevenness of the entire plate surface meets the standard requirements. After the leveling is completed, a second ultrasonic flaw detection is performed to confirm that the bonding rate of the entire plate surface reaches 100%.

2. The silver-steel composite plate explosive welding composite method according to claim 1, characterized in that: In the step 1, after polishing, the roughness of the surface to be bonded is 2-3 um.

3. The silver-steel composite plate explosive welding composite method according to claim 1, characterized in that: In the step 1, the protective film is made of polyethylene film with a thickness of not less than 0.5 mm.

4. The silver-steel composite plate explosive welding composite method according to claim 1, characterized in that: In the step 2, the powdered industrial explosive is an ammonium nitrate-based industrial explosive, which is a mixture of ammonium nitrate and an oil phase material.

5. The silver-steel composite plate explosive welding composite method according to claim 1, characterized in that: In the step 4, the heat treatment temperature is 650° C. and the temperature is kept for 4 hours.

6. The silver-steel composite plate explosive welding composite method according to claim 1, characterized in that: In the step 4, the leveling process is performed using a leveling machine.

7. The silver-steel composite plate explosive welding composite method according to claim 1, characterized in that: In the step 2, calcium carbonate is obtained by crushing stones, and the bran is the product of rice husking.

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