Q490DRL1 explosive welding composite plate for low-temperature storage tank and preparation method of Q490DRL1 explosive welding composite plate

Abstract

The invention belongs to the technical field of explosive welding metal composite plate production and manufacturing, and provides a Q490DRL1 explosive welding composite plate for a low-temperature storage tank and a preparation method of the Q490DRL1 explosive welding composite plate. The preparation method comprises the following steps: respectively pre-treating a substrate Q490DRL1 and clad plate stainless steel to obtain a pre-treated substrate and a pre-treated clad plate; the pretreated base plate is placed on a blasting bed, a pretreated covering plate is installed after a supporting piece is placed on the pretreated base plate, explosive welding is conducted after explosive is laid on the pretreated covering plate, and an explosive welding composite system is obtained; the supporting sheet is a W-shaped supporting sheet; and the explosive welding composite system is subjected to heat treatment, and the Q490DRL1 explosive welding composite board for the low-temperature storage tank is obtained. According to the Q490DRL1 explosive welding composite plate for the low-temperature storage tank, the dilemma that high strength and low-temperature toughness of a traditional material are difficult to consider at the same time is broken through, and excellent toughness can still be kept in a low-temperature environment while high strength is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of explosively welded metal composite plate manufacturing technology, and in particular to a Q490DRL1 explosively welded composite plate for cryogenic storage tanks and its preparation method. Background Technology

[0002] In the petrochemical industry, many chemical reactions require specific low-temperature environments. Cryogenic storage tanks provide stable raw material storage conditions for these reactions, ensuring the continuity and stability of the production process. Taking ethylene production as an example, ethylene, as an important basic chemical raw material, relies on cryogenic storage tanks for its storage and transportation. By cooling ethylene to a cryogenic state and storing it in cryogenic tanks, ethylene volatilization and loss can be effectively reduced, improving production efficiency. Furthermore, in natural gas processing, cryogenic storage tanks are used to store liquefied natural gas (LNG), enabling the transportation and distribution of natural gas under safer and more efficient conditions. The performance of the core materials of cryogenic storage tanks directly determines the safety, reliability, and service life of the tanks. While existing core materials for cryogenic storage tanks can meet the requirements of cryogenic applications, they cannot adapt to special operating conditions, such as corrosive conditions. This places higher demands on the core materials of cryogenic storage tanks. Explosion-welded composite plates for cryogenic storage tanks have emerged due to their unique design concept and advanced manufacturing process. Compared with traditional composite processes, composite materials produced using the explosion welding method have the characteristics of high quality, low price, short construction period, and high efficiency. However, the preparation of Q490DRL1 explosion-welded composite plates has not yet been observed. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a Q490DRL1 explosively welded composite plate for cryogenic storage tanks and its preparation method. The Q490DRL1 explosively welded composite plate for cryogenic storage tanks prepared by this invention achieves significant breakthroughs in several key performance indicators, breaking the dilemma of traditional materials being unable to simultaneously achieve high strength and low-temperature toughness. While ensuring high strength, it can still maintain excellent toughness in low-temperature environments.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing Q490DRL1 explosion-welded composite plates for cryogenic storage tanks, comprising the following steps: The substrate and the cover plate are pretreated separately to obtain a pretreated substrate and a pretreated cover plate. The pretreated substrate is placed on a detonation bed, a support piece is placed on the pretreated substrate, and then the pretreated cover plate is installed. Explosives are then laid on the pretreated cover plate and explosive welding is performed to obtain an explosive welding composite system. The support piece is a W-shaped support piece. The explosive welding composite system is heat-treated to obtain the Q490DRL1 explosive welding composite plate for cryogenic storage tanks. The substrate is made of Q490DRL1 material; The cover plate is made of stainless steel, specifically S31603, S30403, S32168, or S31252. The pretreatment of the cover plate includes the following steps: welding the cover plates together to obtain a welded cover plate; performing a first polishing and leveling on the upper and lower surfaces of the welded cover plate to obtain a leveled cover plate; and performing a second polishing on the mating surface of the leveled cover plate to obtain a pretreated cover plate.

[0005] Preferably, the pretreatment of the substrate includes the following steps: leveling the substrate and then polishing the bonding surface to obtain a pretreated substrate.

[0006] Preferably, the transverse flatness of the pretreated cover plate is 3~4mm / whole width, the longitudinal flatness is 6~12mm / 2m, and the surface roughness of the mating surface is ≤2.0μm; The overall flatness of the pretreated substrate is 8~12mm, the local flatness is 3~5mm / meter, and the surface roughness of the bonding surface is ≤2.0μm.

[0007] Preferably, the thickness of the substrate is 65-80 mm, and the thickness of the cover plate is 3-4 mm.

[0008] Preferably, the support sheets are dispersedly arranged, and the support sheets are divided into edge support sheets and center support sheets. The edge support sheets are linearly arranged around the edge of the pre-treated substrate, and the center support sheets are arranged in an equilateral triangle shape. The spacing between adjacent support sheets is 300~500mm.

[0009] Preferably, the height of the support piece is 7~9mm.

[0010] Preferably, the density of the explosive is 0.92~0.97 g / cm³. 3 The explosive has a detonation velocity of 2000~2200m / s and a briss of 8.5~9.3mm; the explosive contains inert materials.

[0011] Preferably, after the explosive welding, a 100% UT non-destructive testing is performed; if there are non-adhesive parts, the non-adhesive parts are post-processed; the post-processing includes the following steps: after completely removing the non-adhesive parts by grinding, welding repair and grinding are performed in sequence; the conditions for welding repair include: the welding method is GTAW argon arc welding, the transition layer welding material is ER309L, and the cover layer welding material is ER308L or ER316L.

[0012] Preferably, the heat treatment temperature is 610~630℃, the heating rate from room temperature to the heat treatment temperature is 55~120℃ / h, and the holding time is 2~5min / mm; After the heat treatment is completed, cooling is also included; the cooling includes: cooling with the furnace to a first temperature, and then naturally cooling to room temperature; the first temperature is 550~560℃.

[0013] The present invention also provides a Q490DRL1 explosion-welded composite plate for cryogenic storage tanks prepared by the preparation method described in the above technical solution.

[0014] This invention provides a method for preparing Q490DRL1 explosion-welded composite plates for cryogenic storage tanks.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention is produced by explosive welding, which has comprehensive advantages such as good quality, high efficiency, good price and short delivery cycle.

[0016] (2) In this invention, the weld seam of the cover plate is first ground flat and then leveled. While ensuring flatness, the welding stress caused by welding is effectively released. This is more effective than the traditional hammering stress relief method and greatly avoids the risk of explosion cracking or even tearing of the stress concentration area of ​​the cover plate weld seam caused by the huge impact of the explosive welding process.

[0017] (3) The support plates placed on the pre-treated substrate in this invention are different from the traditional V-shaped ones. They are W-shaped, which increases the stability of placement and the support area of ​​a single support plate. This can effectively reduce the number of support plates and increase the quality of explosive welding.

[0018] Furthermore, the density of the explosive is 0.92~0.97 g / cm³. 3 The explosive has a detonation velocity of 2000~2200 m / s and a briss of 8.5~9.3 mm; it contains inert materials. This explosive for explosive welding differs from traditional mixed explosives. The added inert materials have good dispersion and high sensitivity, reducing the detonation velocity to meet the requirements of explosive welding while compensating for the low detonation sensitivity and poor detonation propagation stability of mixed explosives. This explosive for explosive welding also greatly promotes and stabilizes the welding of ultra-long and ultra-wide composite plates.

[0019] Furthermore, the heat treatment temperature is 610~630℃, the heating rate from room temperature to the heat treatment temperature is 55~120℃ / h, and the holding time is 2~5min / mm; after the heat treatment, cooling is also included; the cooling includes: cooling in the furnace to a first temperature, and then naturally cooling to room temperature; the first temperature is 550~560℃. The heat treatment process designed in this invention adopts a low-speed heating, which ensures the temperature uniformity in the heat treatment furnace and the synchronization of the internal temperature of the workpiece during the heating process. The holding temperature avoids the temperature range of 650℃ and 675℃, the sensitization temperature of stainless steel. The cooling process is divided into furnace cooling + air cooling. The furnace cooling stage realizes the synchronous slow cooling of the internal and external temperatures of the workpiece, which helps to release the residual stress of explosive welding. After 550~560℃, the workpiece is removed from the furnace and air-cooled, and then naturally cooled, which can quickly pass through the temperature range of 540℃, the critical sensitization temperature of intergranular corrosion of stainless steel, thus ensuring the comprehensive mechanical and intergranular corrosion resistance properties of the composite plate. Attached Figure Description

[0020] Figure 1 Schematic diagram of the base and cover plate installation structure; Figure 2 A top-view diagram showing the placement of the support plates; Reference numerals: 1-Blast bed, 2-Base plate, 3-“W”-shaped support plate, 4-Covering plate, 5-Explosive frame, 6-Explosive, 7-Digital electronic detonator, 8-Detonator corner line, 9-Initiating explosive, 10-Bamboo strip. Detailed Implementation

[0021] This invention provides a method for preparing Q490DRL1 explosion-welded composite plates for cryogenic storage tanks, comprising the following steps: The substrate and the cover plate are pretreated separately to obtain a pretreated substrate and a pretreated cover plate. The pretreated substrate is placed on a detonation bed, a support piece is placed on the pretreated substrate, and then a pretreated cover plate is installed. Explosives are then laid on the pretreated cover plate and explosive welding is performed to obtain an explosive welding composite system. The support piece is a W-shaped support piece. The explosive welding composite system is heat-treated to obtain the Q490DRL1 explosive welding composite plate for cryogenic storage tanks. The substrate is made of Q490DRL1 material; The cover plate is made of stainless steel, specifically S31603, S30403, S32168, or S31252. The pretreatment of the cover plate includes the following steps: welding the cover plates together to obtain a welded cover plate; performing a first polishing and leveling on the upper and lower surfaces of the welded cover plate to obtain a leveled cover plate; and performing a second polishing on the mating surface of the leveled cover plate to obtain a pretreated cover plate.

[0022] Unless otherwise specified, all raw materials used in this invention are preferably commercially available products.

[0023] The present invention pre-treats the substrate and the cover plate respectively to obtain a pre-treated substrate and a pre-treated cover plate.

[0024] In this invention, the substrate is made of Q490DRL1 material. The Q490DRL1 conforms to GB / T713.6-2023 standard. The substrate thickness is preferably 65-80 mm, specifically 65 mm, 68 mm, 70 mm, 75 mm, 78 mm, or 80 mm. In one specific embodiment, the substrate dimensions are preferably 68 mm × 2640 mm × 11200 mm or 78 mm × 2860 mm × 12500 mm. The pretreatment of the substrate preferably includes the following steps: leveling the substrate and then polishing the bonding surface to obtain a pretreated substrate. The leveling is preferably performed on a roller leveling machine. The leveling achieves straightening of the substrate, ensuring flatness suitable for explosive welding and meeting the general requirements of GB / T709. The bonding surface of the substrate refers to the surface of the substrate that needs to contact and bond with the cover plate. In this invention, the polishing is preferably mechanical polishing, which is preferably achieved using a grinding wheel and a flap wheel. The grinding wheel preferably has a mesh size of 40, and the flap wheel preferably has a mesh size of 80. In this invention, the polishing removes the oxide scale from the substrate, exposing a metallic luster to meet the surface roughness requirements for explosive welding. In this invention, the overall flatness of the pretreated substrate is preferably 8-12 mm, specifically 8 mm, 9 mm, 10 mm, 11 mm, or 12 mm; the local flatness is preferably 3-5 mm / meter, specifically 3 mm / meter, 4 mm / meter, or 5 mm / meter; and the surface roughness of the mating surface is preferably ≤2.0 μm.

[0025] In this invention, the cladding plate is made of stainless steel, specifically S31603, S30403, S32168, or S31252; the stainless steel conforms to GB / T713.7-2023 standard. The thickness of the cladding plate is preferably 3-4 mm. In one specific embodiment, the dimensions of the cladding plate are preferably 4 mm × 2680 mm × 11240 mm or 3 mm × 2900 mm × 12540 mm. The pretreatment of the cladding plate includes the following steps: welding the cladding plates together to obtain a welded cladding plate; performing a first polishing and leveling on the upper and lower surfaces of the welded cladding plate to obtain a leveled cladding plate; and performing a second polishing on the mating surfaces of the leveled cladding plate to obtain a pretreated cladding plate. This invention does not specifically limit the welding method; welding can be performed according to actual needs. In this invention, the first polishing is preferably performed using a flap wheel, preferably with a mesh size of 80. The first polishing is mainly used to treat the weld seam, making the weld seam flush with the base materials on both sides. In this invention, the leveling is preferably performed on a roller leveling machine, preferably a 13-roller leveling machine. In this invention, the leveling improves flatness to meet the flatness requirements of explosive welding. In this invention, the mating surface of the leveled cover plate refers to the surface where the cover plate and the substrate contact and bond. In this invention, the second polishing is preferably performed using a flap wheel, preferably with a mesh size of 120. The second polishing removes the passivation film and oxide layer from the mating surface, exposing a metallic luster. In this invention, the transverse flatness of the pretreated cover plate is preferably 3-4 mm / whole width, and the longitudinal flatness is preferably 6-12 mm / 2 meters; the surface roughness of the mating surface is preferably ≤2.0 μm.

[0026] After obtaining the pretreated substrate and the pretreated cover plate, the present invention places the pretreated substrate on a detonation bed, places a support piece on the pretreated substrate and then installs the pretreated cover plate, and then lays explosives on the pretreated cover plate and performs explosive welding to obtain an explosive welding composite system; the support piece is a W-shaped support piece.

[0027] In this invention, Figure 1 The diagram below shows the installation structure of the base and cover plate. Figure 1 The installation of the base and the cover plate is described in detail.

[0028] In this invention, the material of the blasting bed is preferably a sand-soil mixture, wherein the mass ratio of sand to soil in the sand-soil mixture is preferably 1:0.8~1.2, more preferably 1:1. In this invention, the moisture content of the sand-soil mixture is preferably 8~12%, more preferably 10%. In a specific embodiment of this invention, the dimensions of the blasting bed are preferably 13000mm×3200mm×120mm or 14000mm×3500mm×100mm. In this invention, the preparation method of the blasting bed preferably includes the following steps: laying and compacting the sand-soil mixture using an engineering loader. In this invention, there are no hard boulders or wooden blocks or other debris under the blasting bed, and the upper surface of the blasting bed is relatively flat, without overall undulations or inclination.

[0029] In this invention, the pretreated substrate is preferably placed horizontally on the explosion bed. After the pretreated substrate is placed on the explosion bed, the invention preferably further includes cleaning the bonding surfaces of the pretreated substrate with ethanol.

[0030] In this invention, Figure 2 This is a top-down view of the support plate placement, shown below in conjunction with... Figure 2The placement of the support sheets is described. In this invention, the support sheets are W-shaped support sheets. In this invention, the material of the support sheets is preferably the same as that of the cover plate. In this invention, the opening angle of the W-shaped support sheets is preferably 50~60°. In this invention, the support sheets are preferably distributed in a dispersed manner. In this invention, the support sheets are preferably divided into edge support sheets and center support sheets. In this invention, the edge support sheets are preferably linearly arranged around the edge of the pre-treated substrate, with the "W" opening of the edge support sheets facing the edge, and the distance between the edge support sheets and the edge is preferably less than or equal to 1 mm, specifically preferably 1 mm; the spacing between adjacent support sheets in the edge support sheets is preferably 300~500 mm, specifically preferably 350 mm. In this invention, the central support sheets are preferably arranged in an equilateral triangle shape, with the "W" opening of the central support sheets facing one of the short sides of the pre-treated substrate. The distance between adjacent rows of the central support sheets is preferably 300-500 mm, and the distance between adjacent support sheets in each row is preferably 300-500 mm, specifically 300 mm, 350 mm, 400 mm, 450 mm, or 500 mm. In this invention, the distance between adjacent support sheets in the edge support sheets is smaller than the distance between adjacent support sheets in the central support sheets. In a specific embodiment of this invention, the distance between adjacent support sheets in the edge support sheets is preferably 350 mm; the distance between adjacent rows in the central support sheets is preferably 500 mm, and the distance between adjacent support sheets in each row is preferably 500 mm. In this invention, compared to the central support sheets, the edge support sheets are arranged relatively densely, ensuring both support stability and a smaller amount of support sheets used, thus avoiding the synthesis of intermediate impurity metal phases.

[0031] In this invention, the height of the support sheet is preferably 7-9 mm, specifically 7 mm, 8 mm, or 9 mm. In this invention, the height of the support sheet corresponds to the distance between the pre-treatment substrate and the pre-treatment cover plate.

[0032] In this invention, the pretreatment substrate and the pretreatment cover plate are preferably mounted in a centrally symmetrical manner.

[0033] In this invention, the explosive is preferably placed in a explosive frame, which is preferably formed by vertically fixing gray cardboard along the edge of the pretreated cover plate. In this invention, the thickness of the gray cardboard is preferably 2 mm. In this invention, the height of the explosive frame is preferably 60 mm to protect the laid explosive from leakage. In this invention, the joints between the explosive frames are preferably sealed with transparent tape to prevent explosive leakage at gaps. In this invention, the outer side of the explosive frame is preferably vertically fixed with bamboo strips, so that the explosive frame is at a 90° angle to the pretreated cover plate, to prevent unstable explosive energy at the edges due to frame tilting.

[0034] In this invention, the density of the explosive is preferably 0.92~0.97 g / cm³. 3 Specifically, the preferred value is 0.92 g / cm³. 3 0.93g / cm 3 0.94g / cm 3 0.95g / cm 3 0.96g / cm 3 Or 0.97g / cm 3 The detonation velocity is preferably 2000~2200 m / s, specifically 2000 m / s, 2050 m / s, 2100 m / s, 2106 m / s, 2118 m / s, 2150 m / s, or 2200 m / s; the brute force is preferably 8.5~9.3 mm, specifically 8.5 mm, 8.55 mm, 8.6 mm, 8.7 mm, 8.8 mm, 8.9 mm, 9 mm, 9.1 mm, 9.2 mm, or 9.3 mm. In this invention, the explosive preferably contains inert material. In this invention, the explosive preferably comprises the following components by weight percentage: 45~55% powdered emulsion explosive and 45~55% inert material. The explosive comprises, by weight percentage, 45-55% powdered emulsion explosive, preferably 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, or 55%; the powdered emulsion explosive is preferably a type II rock powdered emulsion explosive. The explosive also comprises, by weight percentage, 45-55% inert material, preferably 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, or 55%; the inert material preferably includes one or more of a dispersant, quartz sand, and mica sand, more preferably quartz sand; the dispersant is not specifically limited in this invention, and any dispersant well known to those skilled in the art can be used. In this invention, the preparation method of the explosive preferably includes the following steps: adding inert material to the powdered emulsion explosive, sieving and mixing once, and manually mixing three times to obtain the explosive. In this invention, the density of the explosive is 0.92-0.97 g / cm³. 3The detonation velocity is 2000~2200m / s, and the saturation is 8.5~9.3mm; it can achieve a good connection between the substrate Q490DRL1 and the stainless steel cladding.

[0035] In this invention, the preferred thickness deviation of the explosive is ±2mm. This invention does not impose a specific limit on the amount of explosive used; those skilled in the art can set the amount based on the material and thickness of the substrate and the cover plate.

[0036] In this invention, the preferred method for laying the explosive includes the following steps: after laying the explosive to the designed height, notify other workers to evacuate; inject approximately 50g of detonating explosive at the center position; apply appropriate pressure to the detonating explosive, making it slightly higher than the surrounding explosive by about 1-2mm; place a digital electronic detonator at the center position of the detonating explosive, connect the detonator's angle line to the blasting main line, and safely evacuate to the blasting area. In this invention, the detonating explosive is preferably a powdered emulsion explosive, specifically preferably a type II rock powdered emulsion explosive.

[0037] In this invention, the preferred operation of the explosive welding includes: after network monitoring is performed using a digital electronic detonator, a safety warning is issued, and the system is detonated to obtain the explosive welding composite system.

[0038] Following the explosive welding, the present invention preferably further includes: cooling the explosively welded product to room temperature and then performing 100% UT non-destructive testing; if there are non-adhesive portions, post-processing is performed on the non-adhesive portions; the post-processing preferably includes the following steps: completely removing the non-adhesive portions, followed by welding repair and grinding. In the present invention, the preferred method for removing the non-adhesive portions is grinding. In the present invention, the conditions for welding repair include: the welding method is preferably GTAW argon arc welding, the transition layer welding material is preferably ER309L, and the dimensions of the ER309L are preferably... The cover layer welding material is ER308L or ER316L, and the preferred size of the ER308L is... The preferred dimensions of the ER316L are... 2.0mm. This invention does not specifically limit the grinding operation, as long as the welding position can be ground until it is flush with the base material.

[0039] After obtaining the explosive welding composite system, the present invention performs heat treatment on the explosive welding composite system to obtain the Q490DRL1 explosive welding composite plate for cryogenic storage tanks.

[0040] In this invention, before the explosive welding composite system is heat-treated, it is preferable to further include cleaning the dirt and debris from the upper and lower surfaces of the explosive welding composite system.

[0041] In this invention, the heat treatment temperature is preferably 610~630℃, specifically 610℃, 620℃ or 630℃; the heating rate from room temperature to the heat treatment temperature is 55~120℃ / h, specifically 55℃ / h, 60℃ / h, 70℃ / h, 80℃ / h, 90℃ / h, 100℃ / h, 110℃ / h or 120℃ / h; the holding time is preferably 2~5min / mm, specifically 2min / mm, 3min / mm, 4min / mm or 5min / mm.

[0042] After the heat treatment is completed, the present invention further includes cooling; the cooling includes: cooling in the furnace to a first temperature, and then naturally cooling to room temperature. In the present invention, the first temperature is preferably 550~560℃.

[0043] In this invention, the heat treatment is preferably carried out in a heat treatment furnace.

[0044] In this invention, the heat treatment preferably includes the following steps: The explosive welding composite system is loaded into a heat treatment furnace at room temperature and heated to the heat treatment temperature at the designed heating rate, and then held at that temperature. After cooling to the first temperature in the furnace, it is taken out and allowed to cool naturally to room temperature.

[0045] After cooling, the present invention preferably further includes a leveling process, during which surface protection is preferably taken into account to avoid local surface defects or imperfections.

[0046] The present invention also provides a Q490DRL1 explosion-welded composite plate for cryogenic storage tanks prepared by the preparation method described in the above technical solution.

[0047] In this invention, the Q490DRL1 explosion-welded composite plate for cryogenic storage tanks meets the requirements of NB / T47002.1-2019B1 grade.

[0048] In this invention, the horizontal end flatness of the Q490DRL1 explosion-welded composite plate for cryogenic storage tanks is preferably 3~6mm / whole width, and the longitudinal long side flatness is preferably 3~5mm / meter.

[0049] The following detailed description, in conjunction with embodiments, of the Q490DRL1 explosion-welded composite plate for cryogenic storage tanks and its preparation method provided by the present invention, should not be construed as limiting the scope of protection of the present invention.

[0050] Example 1 S31603+Q490DRL1 composite plate for cryogenic storage tanks on offshore platforms, with specifications and dimensions of (4mm+66mm)×2600mm×11000mm, conforming to NB / T47002.1-2019 B1 grade.

[0051] The substrate, Q490DRL1, which passed the physicochemical performance test and meets the requirements of GB / T713.6-2023 standard, was selected as the substrate. Its dimensions are 68mm × 2640mm × 11200mm. First, it underwent leveling treatment using a roller leveling machine to achieve an overall flatness of approximately 12mm and a local flatness of 5mm / meter. Then, the substrate mating surfaces were mechanically polished using a 40-grit abrasive wheel and an 80-grit flap wheel to remove oxide scale and expose the metallic luster, ensuring a post-polishing roughness of less than 2.0μm.

[0052] S31603 steel, which has passed the physicochemical performance test and meets the requirements of GB / T713.7-2023 standard, was selected as the cover plate. Welding was carried out according to design requirements, with dimensions of 4mm × 2680mm × 11240mm. An 80-mesh flap wheel was used to polish the upper and lower surfaces of the weld seam to make it flush with the base material on both sides. Then, a 13-roll leveling machine was used to level it, improving flatness to achieve a transverse flatness of 3~4mm / width and a longitudinal flatness of 8~10mm / 2m. A 120-mesh flap wheel was used to polish the mating surface to remove the passivation film and oxide layer, exposing the metallic luster, achieving a surface roughness of less than 1.2μm.

[0053] The blasting bed material is a combination of sand and soil in a 1:1 ratio, with a moisture content of approximately 10%. It is laid and compacted using a bulldozer to form a blasting bed with dimensions of approximately 13000mm x 3200mm and a height of approximately 120mm. There are no hard boulders or wooden blocks or other debris beneath the blasting bed, and the surface is relatively flat without any unevenness or tilt. The prepared substrate is then placed horizontally on the blasting bed, and the mating surfaces are cleaned with ethanol. "W"-shaped support pieces (with an opening angle of 55°) are placed at 350mm intervals along the edge, approximately 1mm from the edge. Inside the edge, "W"-shaped support pieces are arranged in an equilateral triangle at 500mm intervals (500mm between adjacent rows, and 500mm between adjacent support pieces within each row), with a height of 9mm. The cleaned cover plate is then placed horizontally on the support pieces, with proportional allowance around the edges to ensure the cover plate is centered with the substrate. After placement, the mating surfaces are checked for collapse or deformation of the support pieces.

[0054] Along the edge of the cover plate, 2mm thick gray cardboard is used to vertically fix the explosive frame as a 60mm high explosive frame to protect the explosive laid on the plate from leakage. At the same time, the joints between the explosive frames are sealed with transparent tape to prevent explosive leakage from the gaps. Then, bamboo strips are used to vertically fix the explosive frame on the outside so that the explosive frame is at a 90° angle to the cover plate to prevent the explosive energy at the edge from being unstable due to the tilt of the explosive frame.

[0055] An inert material (quartz sand) was added to a powdered emulsion explosive (Type II rock powdered emulsion explosive), the mixture was sieved and mixed once, and then manually stirred three times to obtain a density of 0.94 g / cm³. 3 This is a special explosive for welding with a detonation velocity of 2106 m / s and a brisaccharimetry of 8.40 mm. The explosive is evenly spread on the surface of the covering plate, and then scraped to the designed height using a special tool. A stainless steel ruler is used for measurement and verification, with a deviation of ±2 mm. After ensuring the placement height is correct, other personnel are notified to evacuate. Approximately 50g of powdered emulsion explosive (Type II rock powdered emulsion explosive) is injected into the center position. The powdered emulsion explosive is pressed down appropriately, slightly higher than the surrounding explosive for welding by about 1-2 mm. A digital electronic detonator is placed in the center of the powdered emulsion explosive, and the detonator lead is connected to the blasting main line. The operator then safely evacuates to the blasting area.

[0056] The explosive was detonated using a specialized detonator, yielding an S31603+Q490DRL1 explosively welded composite plate for cryogenic storage tanks on offshore platforms. After 100% UT non-destructive testing, it was found to be 100% metallurgically bonded except at the detonation point. The diameter of the detonator zone at the detonation point was... If the bonding is incomplete and does not meet the 100% bonding requirement for Class B1 in Table 2 of NB / T47002.1-2019, the coating in the detonator area at the detonation point must be completely removed by mechanical grinding down to 1.5mm of the substrate. After 100% PT testing confirms that the non-bonding area at the detonation point has been completely removed, a certified welder shall repair the damage using GTAW TIG welding according to PQR and WPS standards as qualified by NB / T47014. The transition layer welding material shall be selected as... Selected welding materials for the cover layer After welding, the welded area was ground until it was flush with the base material. After the temperature dropped to room temperature, PMI and 100% PT+UT tests were performed, and both showed that they were qualified.

[0057] After cleaning the dirt and debris from the upper and lower surfaces of the composite board, it is placed into a heat treatment furnace at room temperature. The designed holding temperature is 620±10℃, the heating rate is 60℃ / h, and the holding time after reaching the temperature is 216min. After the holding time is completed, it is cooled in stages, slowly cooled with the furnace, and removed from the furnace after the temperature drops to 550℃, and then allowed to cool naturally.

[0058] After the composite board is removed from the furnace, it is allowed to cool naturally in the air until the surface temperature drops to approximately 30°C, at which point it undergoes leveling. During leveling, care is taken to protect the surface and avoid localized surface defects or imperfections. After leveling, the flatness of the transverse ends of the composite board should reach 3-5 mm / width, and the flatness of the longitudinal long side should reach 3 mm / meter, with no localized deformation or undulation along the entire long side. Then, a 100% UT test is performed again to meet the Class B1 requirements in Table 3 of NB / T47002.1-2019.

[0059] The impact absorption energy (KV2) at -40℃ for substrate Q490DRL1 was tested using GBT713.6-2023. The results were: -40℃ impact absorption energy (KV2) of 183J, 197J, and 193J, with an average of 191J, meeting the standard requirement of ≥80J. The intergranular corrosion resistance of cladding S31603 was tested using GBT4334-2020 Method E, and the results showed that it met the standard for intergranular corrosion resistance of cladding.

[0060] The interfacial shear strength of the composite plate was tested using the NBT47002-2019 method, and the tensile strength was tested using GBT6396-2008. The results showed that the interfacial shear strength reached 295 MPa, and the interfacial corrugations were fine and uniform small corrugations; the tensile strength reached 200 MPa. The composite plate was then subjected to edge flame cutting, and 100% PT testing was performed on the cut surfaces at the joints. The stainless steel surface had a polished roughness of approximately 1.6 μm. After visual inspection and approval of the surface quality, the plate was packaged with vapor phase rust inhibitor paper and stored. This yielded a single S31603+Q490DRL1 explosion-welded composite plate for cryogenic storage tanks on offshore platforms, which passed all tests and met the requirements of NB / T47002.1-2019 Class B1.

[0061] Example 2 S30403+Q490DRL1 composite plate for cryogenic storage tanks, with specifications and dimensions of (3mm+76mm)×2830mm×12370mm, conforming to NB / T47002.1-2019 B1 grade.

[0062] The substrate Q490DRL1, which passed the physicochemical performance test and conforms to the GB / T713.6-2023 standard, was selected. Its dimensions are 78mm × 2860mm × 12500mm. While its flatness meets the general requirements of GB / T709, it does not meet the flatness requirements for the exploded welded composite plate. Therefore, it was first leveled using a roller leveler combined with a hydraulic press to achieve an overall flatness of approximately 10mm and a local flatness of 3mm / meter. The mating surfaces of the substrate were then mechanically polished using a 40-grit abrasive wheel and an 80-grit flap wheel to remove rust and oxide scale, revealing a metallic luster and achieving a surface roughness of less than 1.6μm. This was then ready for use.

[0063] S30403 steel, which has passed the physicochemical performance test and meets the requirements of GB / T713.7-2023 standard, was selected as the cover plate. Welding was performed according to design requirements and dimensions, with one weld seam. The dimensions were 3mm × 2900mm × 12540mm. The upper and lower surfaces of the weld seam were polished with an 80-mesh flap wheel to make the upper surface of the weld seam flush with the base material on both sides. Then, a 13-roll leveling machine was used to remove imperfections, improving flatness to achieve a transverse flatness of approximately 3-4mm / width and a longitudinal flatness of approximately 6-10mm / 2 meters. A 120-mesh flap wheel was used to polish the mating surfaces to remove the passivation film and oxide layer, exposing the metallic luster. The surface roughness of the mating surfaces reached below 1.2μm, and the surface was then ready for use.

[0064] The blasting bed material is a combination of sand and soil in a 1:1 ratio, with a moisture content of approximately 10%. It is laid and compacted using a bulldozer to form a blasting bed with dimensions of approximately 14000mm x 3500mm and a thickness of approximately 100mm. There are no hard boulders or wooden blocks or other debris beneath the blasting bed, and the surface is relatively flat without any unevenness or tilt. The prepared substrate is then placed horizontally on the blasting bed, and the mating surfaces are cleaned with ethanol. "W"-shaped support pieces (with an opening angle of 55°) are placed at 350mm intervals along the edge, approximately 1mm from the edge. Inside the edge, "W"-shaped support pieces are arranged in an equilateral triangle at 500mm intervals (500mm between adjacent rows, and 500mm between adjacent support pieces within each row). The support pieces are 7mm high. The cleaned cover plate is then placed horizontally on the support pieces, with proportional allowance around the edges, ensuring the cover plate is centered with the substrate. After placement, the support pieces are checked for collapse or deformation at the mating surfaces.

[0065] Along the edge of the cover plate, 2mm thick gray cardboard is used to vertically fix the explosive frame as a 60mm high explosive frame to protect the explosive laid on the plate from leakage. At the same time, the joints between the explosive frames are sealed with transparent tape to prevent explosive leakage from the gaps. Then, bamboo strips are used to vertically fix the explosive frame on the outside so that the explosive frame is at a 90° angle to the cover plate to prevent the explosive energy at the edge from being unstable due to the tilt of the explosive frame.

[0066] An inert material (quartz sand) was added to a powdered emulsion explosive (Type II rock powdered emulsion explosive), the mixture was sieved and mixed once, and then manually stirred three times to obtain a density of 0.96 g / cm³. 3This is a special explosive for welding with a detonation velocity of 2118 m / s and a briss of 8.55 mm. The explosive comprises 47% powdered emulsion explosive and 53% inert material by weight. The explosive is evenly spread on the surface of the covering plate, and then scraped to the designed height using a special tool. A stainless steel ruler is used for measurement and verification, with a deviation of ±2 mm. After ensuring the placement height is correct, other personnel are notified to evacuate. Approximately 50g of powdered emulsion explosive (Type II rock powdered emulsion explosive) is injected into the center position. The powdered emulsion explosive is then pressed down appropriately, slightly higher than the surrounding explosive for welding by about 1-2 mm. A digital electronic detonator is placed in the center of the powdered emulsion explosive, and the detonator lead is connected to the blasting main line. The operator then safely evacuates to the blasting area.

[0067] After network monitoring using a digital electronic detonator-specific initiator confirmed to be error-free, a safety warning was issued, and detonation was initiated. This yielded an S30403+Q490DRL1 explosively welded composite plate for cryogenic storage tanks. Following 100% UT (Undertested Test) non-destructive testing, it was found to be 100% bonded except at the detonation point. The diameter of the detonator zone at the detonation point was [not specified]. The bonding is incomplete and does not meet the 100% bonding requirement for Class B1 in Table 2 of NB / T47002.1-2019. Therefore, the detonator area coating at the detonation point needs to be completely removed by mechanical grinding, down to 1.5mm from the substrate. After 100% PT testing confirms that the non-bonding area at the detonation point has been completely removed, a certified welder shall perform welding repair according to PQR and WPS standards as qualified by NB / T47014. The welding method is GTAW (Gargon arc welding), and the transition layer welding material is selected as... 0mmER309L, cover layer welding material selection After welding, the welded area was ground until it was flush with the base material. After the temperature dropped to room temperature, PMI and 100% PT+UT tests were performed, and both showed that they were qualified.

[0068] After cleaning the dirt and debris from the upper and lower surfaces of the composite board, it is placed into the heat treatment furnace at room temperature. The designed holding temperature is 620±10℃, the heating rate is 60℃ / h, and the holding time after reaching the temperature is 243min. After the holding time is completed, it is cooled in stages and slowly cooled with the furnace. After the temperature drops to 550℃, it is taken out of the furnace and allowed to cool naturally.

[0069] After the composite board is removed from the oven, it is left to cool for approximately 8 hours until the surface temperature drops to around 30°C before leveling. The leveling process uses a three-roll leveler and a hydraulic press in conjunction. During leveling, care is taken to protect the surface and avoid localized damage, indentations, and pitting. After leveling, the horizontal flatness of the composite board should reach 4-6 mm / width, and the longitudinal flatness should reach 5 mm / 2 meters, with no localized deformation or undulations along the entire long side. Then, a 100% UT test is performed again to ensure 100% bonding and meet the B1 grade requirements in Table 3 of NB / T47002.1-2019.

[0070] The impact absorption energy (KV2) at -40℃ for substrate Q490DRL1 was tested using GBT713.6-2023. The results were: -40℃ impact absorption energy (KV2) of 198J, 216J, and 207J, with an average of 207J, meeting the standard requirement of ≥80J. The intergranular corrosion resistance of cladding S30403 was tested using GBT4334-2020 Method E, and the results met the standard for intergranular corrosion resistance of cladding.

[0071] The interfacial shear strength of the composite plate was tested using the NBT47002-2019 method, and the tensile strength was tested using GBT6396-2008. The results showed that the interfacial shear strength reached 310 MPa and the tensile strength reached 480 MPa. The composite plate was then edge-cut, and the cut surfaces with corrugated joints passed 100% PT testing. The surface roughness was approximately 2.0 micrometers. After visual inspection and approval of the surface quality, the plate was packaged with vapor phase rust inhibitor paper and stored. This yielded a cryogenic storage tank S30403+Q490DRL1 explosion-welded composite plate that passed all tests and met the requirements of NB / T47002.1-2019 B1 grade.

[0072] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a Q490DRL1 explosion-welded composite plate for cryogenic storage tanks, comprising the following steps: The substrate and the cover plate are pretreated separately to obtain a pretreated substrate and a pretreated cover plate. The pretreated substrate is placed on a detonation bed, a support piece is placed on the pretreated substrate, and then the pretreated cover plate is installed. Explosives are then laid on the pretreated cover plate and explosive welding is performed to obtain an explosive welding composite system. The support piece is a W-shaped support piece. The explosive welding composite system is heat-treated to obtain the Q490DRL1 explosive welding composite plate for cryogenic storage tanks. The substrate is made of Q490DRL1 material; The cover plate is made of stainless steel, specifically S31603, S30403, S32168, or S31252. The pretreatment of the cladding includes the following steps: welding the cladding together to obtain a welded cladding; The upper and lower surfaces of the welded cladding are first polished and leveled to obtain a leveled cladding; the mating surfaces of the leveled cladding are then second polished to obtain a pre-treated cladding.

2. The preparation method according to claim 1, characterized in that, The pretreatment of the substrate includes the following steps: leveling the substrate and then polishing the bonding surface to obtain a pretreated substrate.

3. The preparation method according to claim 1 or 2, characterized in that, The pre-treated cover plate has a transverse flatness of 3~4mm / whole width, a longitudinal flatness of 6~12mm / 2m, and a surface roughness of ≤2.0μm on the mating surface; The overall flatness of the pretreated substrate is 8~12mm, the local flatness is 3~5mm / meter, and the surface roughness of the bonding surface is ≤2.0μm.

4. The preparation method according to claim 1, characterized in that, The thickness of the substrate is 65-80 mm, and the thickness of the cover plate is 3-4 mm.

5. The preparation method according to claim 1, characterized in that, The support sheets are dispersedly arranged, and the support sheets are divided into edge support sheets and center support sheets. The edge support sheets are linearly arranged around the edge of the pre-treated substrate, and the center support sheets are arranged in an equilateral triangle shape. The spacing between adjacent support sheets is 300~500mm.

6. The preparation method according to claim 1, characterized in that, The height of the support plate is 7~9mm.

7. The preparation method according to claim 1, characterized in that, The density of the explosive is 0.92~0.97 g / cm³. 3 The explosive has a detonation velocity of 2000~2200m / s and a briss of 8.5~9.3mm; the explosive contains inert materials.

8. The preparation method according to claim 1, characterized in that, After the explosive welding, 100% UT non-destructive testing is also performed; if there are non-adhesive parts, the non-adhesive parts are post-processed; the post-processing includes the following steps: after completely removing the non-adhesive parts by grinding, welding repair and grinding are performed in sequence; the conditions for welding repair include: the welding method is GTAW argon arc welding, the transition layer welding material is ER309L, and the cover layer welding material is ER308L or ER316L.

9. The preparation method according to claim 1, characterized in that, The heat treatment temperature is 610~630℃, the heating rate from room temperature to the heat treatment temperature is 55~120℃ / h, and the holding time is 2~5min / mm; After the heat treatment is completed, cooling is also included; the cooling includes: cooling with the furnace to a first temperature, and then naturally cooling to room temperature; the first temperature is 550~560℃.

10. The Q490DRL1 explosion-welded composite plate for cryogenic storage tanks prepared by the preparation method according to any one of claims 1 to 9.

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