A double-sided composite steel plate for refining and chemical equipment and its preparation method

Abstract

This invention discloses a double-sided composite steel plate for refining and chemical equipment and its preparation method. The chemical composition of the base layer of the composite steel plate is C 0.12%–0.17%, Si 0.10%–0.30%, Mn 1.30%–1.60%, P ≤0.006%, S ≤0.002%, Ni 1.0%–1.5%, and Ti 0.02%–0.06%. The chemical composition of the cladding layer is C 0.02%–0.04%, Si 0.30%–0.80%, Mn 1.20%–1.60%, P ≤0.010%, S ≤0.003%, Cr 16.0%–19.0%, Ni 8.0%–13.0%, and Ti 0.03%–0.10%. The preparation method includes double-sided composite billet assembly, billet heating, rolling, hot straightening, slow cooling, and heat treatment. This method can obtain thick double-sided composite steel plates with multiple layers (3-6 mm), a base layer (30-60 mm), and another multiple layer (3-6 mm). This meets the requirements of high-performance, long-life, and large-size double-sided composite steel plates for refining equipment, supports the high-end metal materials needed by my country's petroleum refining industry, and promotes the high-speed and large-scale development of refining equipment.

Description

Technical Field

[0001] This invention relates to the field of metallic materials, and in particular to a double-sided composite steel plate for refining and chemical equipment and its preparation method. Background Technology

[0002] The petroleum refining industry is one of the industrial sectors with the most diverse products, the largest number of equipment, and the most complex environment. At high temperatures, various oils, hydrocarbons, esters, acids, alkalis, semi-finished products, finished products, and catalysts undergo chemical reactions in refining plants, posing a significant challenge to the safe operation of refining equipment. Therefore, to ensure the safety and reliability of refining equipment, stainless steel or alloys are generally used to manufacture chemical equipment. However, due to the massive volume of use, the construction and subsequent maintenance costs of refining equipment are extremely high. Consequently, in recent years, the use of stainless steel composite materials to replace single stainless steel or corrosion-resistant alloys has become a development trend in refining equipment materials. However, due to differences in manufacturing capabilities and processes, metallurgical enterprises face varying degrees of constraints and shortcomings in manufacturing composite plates, affecting output and overall performance.

[0003] Prior to this invention, the published invention patent "Explosive Welding Method for 310S Austenitic Stainless Steel Composite Steel Plate" (Publication No. CN 101559525 A) shows that the manufacturing method of this patent is an explosive bonding method. This method obtains a composite steel plate by explosive welding after simple surface treatment of the substrate and composite material. Although the ultrasonic flaw detection is 100% qualified, the explosive bonding method will result in uneven bonding effect due to uneven explosive force. The shear force at the bonding interface is small, which affects the service life and effect.

[0004] The published invention patent "A method for manufacturing an explosive composite plate" (publication number CN 105562920 A) shows that the patent solves the problem of low bonding rate of explosive composite plates by adding a sandwich layer. However, in the final analysis, this method is still a single explosive composite method. Although it improves the interface bonding rate, the shear strength of the bonding interface is not specifically reflected.

[0005] The published invention patent "A high-grade extra-thick double-sided wear-resistant composite plate and its production method" (publication number CN110592473A) shows that the patent uses a vacuum billet method as the rolling raw material. As is well known, this method requires fine grinding of the substrate and composite material surfaces, followed by vacuum treatment. This method is complicated and requires vacuum equipment, which increases equipment costs.

[0006] The published invention patent "A high corrosion resistant marine composite steel plate and its manufacturing method" (publication number CN111361235A) shows that the patent is a design for a composite steel plate for shipbuilding. It uses a four-layer symmetrical vacuum billet assembly method as the rolling raw material. Since the surface and side cleaning of the four billets is required, it increases the cumbersome process and the cost of vacuum equipment.

[0007] The main shortcomings of the aforementioned patented composite steel plate invention are: the composite steel plates for chemical equipment prepared by explosive bonding exhibit uneven bonding strength and low bonding rate, making them unsuitable for producing large-width double-sided composite steel plates. Furthermore, explosive bonding easily damages the original fundamental properties of the steel, which cannot be restored, affecting the safety and service life of the equipment during application. In contrast, composite plates using vacuum assembly require vacuum equipment, significantly increasing production costs, and the process necessitates double-symmetrical assembly, making them unsuitable for producing thick double-sided composite steel plates. Summary of the Invention

[0008] The purpose of this invention is to provide a double-sided composite steel plate for refining and chemical equipment and its preparation method. By adopting a new composition and production process, this invention develops a high-performance, long-life, and large-size double-sided composite steel plate that meets the needs of refining and chemical equipment, supports the high-end metal materials required by my country's petroleum refining industry, and helps the high-speed and large-scale development of refining and chemical equipment.

[0009] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0010] A double-sided composite steel plate for refining and chemical equipment, wherein the chemical composition of the base layer is, by weight percentage, C 0.12%–0.17%, Si 0.10%–0.30%, Mn 1.30%–1.60%, P≤0.006%, S≤0.002%, Ni 1.0%–1.5%, Ti 0.02%–0.06%, with the balance being Fe and unavoidable inclusions; the chemical composition of the cladding layer is, by weight percentage, C 0.02%–0.04%, Si 0.30%–0.80%, Mn 1.20%–1.60%, P≤0.010%, S≤0.003%, Cr 16.0%–19.0%, Ni 8.0%–13.0%, Ti 0.03%–0.10%, with the balance being Fe and unavoidable inclusions.

[0011] Furthermore, the thickness of the composite steel plate is 3-6mm for the cladding layer + 20-60mm for the base layer + 3-6mm for the cladding layer, and the width is 2000-4000mm.

[0012] Furthermore, the R of the composite steel plate at 500℃ m ≥500MPa, unbonded rate 0%, shear strength ≥370MPa.

[0013] Furthermore, the composite steel plate did not fracture after 720 hours of SSC testing at 500℃ and 0.5MPa standard atmospheric pressure, and the ultrasonic flaw detection achieved Level I.

[0014] Furthermore, the cladding layer of the composite steel plate passed the test for intergranular corrosion resistance after being kept at 650℃ for 2 hours.

[0015] A method for preparing a double-sided composite steel plate for refining and chemical equipment includes: double-sided composite billet assembly—composite billet heating—rolling—hot straightening—slow cooling—heat treatment, wherein:

[0016] Heating of composite billet: The double-sided composite billet is heated in a heating furnace to 1180-1230℃ for a total heating time of 4-6 hours. The composite billet is descaled before being rolled out of the furnace.

[0017] Rolling: Rolling is completed entirely at high temperatures. The reduction in the first two rolling passes is controlled at 10–20 mm, and the roll speed is 1.0–2.0 m / s. The rolling process consists of 10–13 passes, with a final rolling temperature ≥900℃. After rolling, the steel plate is straightened and flattened by a hot straightener. After being removed from the line, it is stacked for slow cooling at a temperature ≥400℃ for 24–36 hours. The specifications of the rolled composite plate are [(3–6) + (30–60) + (3–6)] mm × (2000–4000) mm × L. 板 mm;

[0018] Heat treatment: Relieve post-rolling internal stress at 300-400℃, hold for 0.5-1.0h; normalizing at 900-950℃, hold for 1.0-1.5min / mm; relieve post-weld stress at 660-690℃, hold for 2.0-4.0h.

[0019] Furthermore, the double-sided composite preform assembly includes: combining a base preform and a composite material into a single-sided composite assembly by means of surface polishing, preform assembly, and explosive bonding; and then combining the other surface of the base preform of the single-sided composite assembly with another composite material by means of surface polishing, preform assembly, and explosive bonding to form a double-sided composite assembly. At this time, the acceptable bonding rate of the upper and lower bonding layers of the assembly is 40% to 60%, and the shear strength is 100 to 150 MPa.

[0020] Furthermore, the surface polishing includes polishing and grinding one surface of the blank and composite material, so that the surface is free of rust and oil stains, exposes a metallic luster, and the surface roughness Ra is 15 to 25 μm.

[0021] Further, the assembly includes: uniformly mixing an agent composed of iron powder and nickel powder in a certain proportion, with the mass ratio of iron powder to nickel powder being 30:1 to 10:1, and uniformly spreading it on the surface of the polished base blank with a thickness ranging from 0.1 to 0.3 mm; the nickel powder having a purity of 99.9% or higher and a particle size of 2 to 10 μm; the iron powder having a purity of 99.9% or higher and a particle size of 2 to 10 μm; placing the composite material on the agent, aligning the four sides of the assembled blank, and fixing the four sides of the assembled blank by spot welding.

[0022] Furthermore, the explosion is performed by selecting 4 to 9 0.5m² atomization points on the surface of the composite material according to the size specifications of the composite blank. 2 A layer of explosives 10-30mm thick is laid over small areas, and the areas are connected by explosives. The amount of explosives used is (10-15) kg / m². 2 The high-pressure pulse load generated by the explosion connects and fixes the base blank and composite metal.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The base layer of this invention utilizes solid solution strengthening and carbide precipitation strengthening through the addition of Mn, Ni, and Ti alloying elements to ensure the basic strength of the composite steel plate, especially its high-temperature strength, high-temperature oxidation resistance, and formability. The cladding layer uses Cr, Ni, and Ti alloying elements to ensure its excellent corrosion resistance.

[0025] 2. By using a small amount of explosives to prepare a double-sided composite billet, the composite bonding rate only needs to be 40% to 60%, and the shear strength at the bonding point only needs to be 100 to 150 MPa. The advantages of this composite billet preparation are that the environmental pollution caused by the explosion is small, the billet specifications are flexible, no expensive equipment investment is required, and the cost is low.

[0026] 3. This invention can obtain a thick double-sided composite steel plate with a layer (3-6mm) + a base layer (30-60mm) + a layer (3-6mm), with a width of up to 2000-4000mm, and an R value at 500℃. m With a strength of ≥500MPa, a non-bonding rate of 0%, and a shear strength of ≥370MPa, the SSC did not fracture after 720h at 500℃ and 0.5MPa standard atmospheric pressure. The ultrasonic flaw detection reached Level I. The intergranular corrosion performance of the cladding layer after being kept at 650℃ for 2h was qualified, which can meet the requirements of the complex application environment of refining and chemical equipment. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The described embodiments are merely some, not all, of the embodiments of this invention. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0028] A double-sided composite steel plate for refining and chemical equipment, wherein the chemical composition of the base layer, by weight percentage, is C 0.12%–0.17%, Si 0.10%–0.30%, Mn 1.30%–1.60%, P≤0.006%, S≤0.002%, Ni 1.0%–1.5%, Ti 0.02%–0.06%, with the balance being Fe and unavoidable inclusions. The chemical composition of the cladding layer, by weight percentage, is C 0.02%–0.04%, Si 0.30%–0.80%, Mn 1.20%–1.60%, P≤0.010%, S≤0.003%, Cr 16.0%–19.0%, Ni 8.0%–13.0%, Ti 0.03%–0.10%, with the balance being Fe and unavoidable inclusions.

[0029] Reasons for the design of the chemical composition of the base steel plate:

[0030] C: In this invention, carbon is the most important element for improving the strength of the composite plate base layer. The strength of the matrix is ​​strengthened by solid solution, ensuring the room temperature and high temperature strength of the base steel plate. However, excessive carbon content is not conducive to welding and processing performance. Therefore, this invention sets the C content range to 0.12% to 0.17%.

[0031] Si: In this invention, Si is used as a reducing agent and deoxidizer in the steelmaking process. However, in the tempering embrittlement temperature range of 350 to 550°C, excessive silicon content will lead to an increase in the tempering embrittlement sensitivity of steel. Therefore, this invention should not add too much silicon. Thus, the Si content range is set to 0.10% to 0.30%.

[0032] Mn: In this invention, since the amount of deoxidizer Si added is relatively small, the addition of Mn makes up for the insufficient deoxidation effect. In addition, Mn is an alloying element with strong solid solution strengthening ability, which improves the strength of the matrix. However, Mn is the main factor affecting temper brittleness, and this invention needs to strictly control it. Therefore, the Mn content range is set to 1.30% to 1.60%.

[0033] S and P: Sulfur and phosphorus are harmful elements in steel. To ensure the purity and comprehensive performance of steel, they must be strictly controlled. Therefore, the limits are S≤0.002% and P≤0.006%.

[0034] Ni: In this invention, nickel strengthens ferrite and refines pearlite, thereby improving the strength of the base layer, but its effect on plasticity is not significant. In particular, for this normalized low-alloy steel, a certain amount of nickel can improve the strength of the steel without significantly reducing its toughness. Therefore, this invention sets the Ni content range to 1.0%-1.50%.

[0035] Ti: Titanium is a strong ferrite-forming element, significantly increasing the A1 and A3 temperatures of steel. Titanium improves the plasticity and toughness of the steel of this invention. Since titanium fixes carbon, forming titanium carbide, which increases the matrix strength, the Ti content in this invention is set in the range of 0.02% to 0.06%.

[0036] Reasons for the design of the chemical composition of the upper and lower strata plates:

[0037] C: Carbon can significantly improve the strength of the cladding and stabilize austenite, but too much carbon will combine with chromium to form chromium carbides, resulting in a decrease in the chromium content in solid solution, which seriously affects the corrosion resistance of the cladding metal. Therefore, the present invention sets the C content range to 0.02% to 0.04%.

[0038] Si: In this invention, in addition to acting as a reducing agent and deoxidizer in the steelmaking process, silicon also increases the electrode potential of the cladding metal, reduces the number of microcells, and effectively improves the corrosion resistance of steel. It can also form a dense oxide film on the cladding surface, improving corrosion resistance. However, excessive silicon will increase the brittleness of steel. Therefore, this invention should not add too much silicon. Thus, the Si content range is set to 0.30% to 0.80%.

[0039] Mn: In this invention, Mn is a solid solution strengthening element that improves the strength of the cladding layer and increases the shear strength at the bonding joint. At the same time, manganese can form oxides with chromium to form a dense oxide film, which prevents the corrosion of oxygen, water and other media, thereby improving the corrosion resistance of the cladding layer. However, excessive Mn affects the temper brittleness of the cladding layer. Therefore, this invention sets the Mn content range to 1.20% to 1.60%.

[0040] S and P are harmful elements in steel. To ensure the purity of steel and improve its performance, they must be strictly controlled. Therefore, the limits are S≤0.003% and P≤0.010%.

[0041] Cr: The addition of chromium alloying element to the cladding plate mainly utilizes chromium's corrosion resistance properties. In oxidizing media, it forms a strong and dense layer of chromium oxide on the steel surface, protecting the steel plate substrate. Chromium dissolved in steel can significantly increase the electrode potential of the steel, reducing electrochemical corrosion caused by different electrode potentials. Therefore, the Cr content in this invention is controlled at 16.0% to 19.0%.

[0042] Ni: is an austenitic element that can expand the passivation range of stainless steel in non-oxidizing media and effectively improve the passivation ability of stainless steel. Therefore, the present invention controls the Ni content to be between 8.0% and 13.0%.

[0043] Ti can form very strong titanium carbide, which can be stable up to 1300℃. This highly dispersed titanium carbide particles, stable up to high temperatures, can refine grains and strengthen the matrix. Furthermore, free carbon is formed into strong titanium carbide, preventing the precipitation of chromium carbide along austenite grain boundaries during heating, thus preventing intergranular corrosion. Therefore, the Ti content in this invention is controlled at 0.03% to 0.10%.

[0044] A method for preparing a double-sided composite steel plate for refining and chemical equipment is as follows:

[0045] Process path: Double-sided composite billet assembly (basic billet, composite material specification design - surface polishing - billet assembly - explosive bonding) - composite billet heating - rolling - hot straightening - slow cooling - heat treatment - flaw detection - inspection and testing.

[0046] 1) Rationally design the specifications of the billet and composite materials. The billet preparation specifications are: thickness (120~360mm) × width (2000~4000mm) × length. 坯 mm, corresponding to the upper composite material preparation specifications (12~36mm) thickness × (2000~4000mm) width × L 材 mm, lower layer composite material preparation specifications (12~36mm) thickness × (2000~4000mm) width × L 材 mm, L 坯 =L 材 .

[0047] 2) Polish and grind one surface of the blank and composite material first. The surface should be free of rust, oil stains and other impurities and defects, and should have a metallic luster. The surface should not be too smooth to prevent metal atoms from sliding during an explosion. Without a point of force, the bonding will be poor. The roughness Ra should be 15 to 25 μm.

[0048] 3) Mix iron powder and nickel powder evenly in a ratio of 30:1 to 10:1 by mass, and spread evenly on the surface of the polished base blank to a thickness of 0.1 to 0.3 mm. The nickel powder should have a purity of ≥99.9% and a particle size of 2 to 10 μm; the iron powder should also have a purity of ≥99.9% and a particle size of 2 to 10 μm. Place the composite material on the mixture, aligning the four sides of the assembly. Fix the perimeter of the composite blank by spot welding to prevent movement of the composite material during the explosion.

[0049] 4) Based on the dimensions and specifications of the composite blank, select 4 to 9 1m spots on the surface of the composite material. 2 A layer of explosives 10-30mm thick is laid over small areas, and the areas are connected by explosives. The amount of explosives used is (10-15) kg / m².2 By using the high-pressure pulse load generated by the explosion, the base blank and composite metal are connected and fixed to create a single-sided composite assembly.

[0050] 5) Repeat steps 2 to 4 on the other surface of the single-sided composite substrate and another composite material to form a new double-sided composite. At this time, the acceptable bonding rate of the upper and lower bonding layers of the composite is 40% to 60%, and the shear strength is 100 to 150 MPa.

[0051] 6) The double-sided composite billet is heated in a furnace to 1180–1230℃ for a total heating time of 4–6 hours. Through this high-temperature heating stage, the gaseous steel at the composite interface is fully expelled, and active atoms in the base and cladding materials diffuse and migrate at the interface, forming a metallurgical bond. The composite billet is descaled before rolling. Rolling is completed entirely at high temperature. Because the bonding interface is close to the upper and lower surfaces of the composite billet, the reduction in the first two rolling passes should not be too large, prioritizing sufficient bonding. The reduction should be controlled at 10–20 mm to prevent excessive deformation that could lead to cracking of the bonding layer. The roll speed is 1.0–2.0 m / s. The rolling process consists of 10–13 passes, with a final rolling temperature ≥900℃. After rolling, the steel plates are straightened and flattened by a hot straightening machine. After being removed from the line, they are stacked and slowly cooled at a temperature ≥400℃ for 24–36 hours. The specifications of the rolled composite plate are [(3–6) + (30–60) + (3–6)] mm × (2000–4000) mm × L. 板 mm.

[0052] 7) The composite plate obtained after rolling retains certain internal stress at the interface, which needs to be eliminated by heat treatment. The heat treatment temperature for eliminating post-rolling internal stress is 300-400℃, and the holding time is 0.5-1.0h. The composite steel plate has high strength after rolling but poor plasticity and toughness, which cannot meet the mechanical performance requirements of refining and chemical plants. Further normalizing heat treatment is needed to improve its performance. Therefore, the normalizing temperature of this invention is 900-950℃, and the holding time is 1.0-1.5min / mm. Finally, the final mechanical properties of the composite plate are tested by a heat treatment process to eliminate post-weld stress. The temperature for eliminating post-weld stress is 660-690℃, and the holding time is 2.0-4.0h. Finally, a double-sided refining and chemical composite steel plate with bainitic tempered structure as the base layer and austenitic structure as the cladding layer is obtained.

[0053] The embodiments are used to specifically illustrate the content of the present invention. These embodiments are only general descriptions of the content of the present invention and do not limit the content of the present invention. Table 1 Chemical composition of the embodiments of the present invention; Table 2 Process parameters for preparing composite billets of the embodiments of the present invention; Table 3 Rolling and heat treatment process parameters of the embodiments of the present invention; Table 4 Final effect of microstructure and properties of the embodiments of the present invention; Table 5 Internal and external quality of the embodiments of the present invention; Table 6 SCC resistance test results of steel under high temperature and high pressure of the embodiments of the present invention; Table 7 Full immersion test of the embodiments of the present invention in 5.0% NaCl solution at 100℃ for 720h.

[0054] Table 1 Chemical composition (wt, %) of embodiments of the present invention

[0055]

[0056] Table 2. Process parameters for preparing the composite billet in the embodiments of the present invention.

[0057]

[0058]

[0059] Table 3 Rolling and heat treatment process parameters of the embodiments of the present invention

[0060]

[0061] Table 4 Mechanical properties of embodiments of the present invention

[0062]

[0063]

[0064] Table 5 Internal and External Quality of Embodiments of the Invention

[0065]

[0066] Table 6. SCC resistance test results of the embodiments of the present invention under high temperature and high pressure.

[0067] Example Under test conditions of 500℃ and 0.5MPa, the loading time was 720h. 1 No breakage 2 No breakage 3 No breakage 4 No breakage 5 No breakage 6 No breakage

[0068] Table 7 shows the 720-hour total immersion test of the embodiments of the present invention in a 5.0% NaCl solution at 100°C.

[0069]

[0070]

[0071] Based on the above results, it can be concluded that the double-sided composite steel plate with a thickness of 3-6mm + base layer (30-60mm) + 3-6mm provided by this invention can have a width of 2000-4000mm and an R value at 500℃. m With a shear strength of ≥500MPa, a non-bonding rate of 0%, and a shear strength of ≥370MPa, the SSC did not fracture after 720h at 500℃ and 0.5MPa standard atmospheric pressure. The ultrasonic flaw detection reached Level I, and the intergranular corrosion performance of the cladding layer after being kept at 650℃ for 2h was qualified.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A double-sided composite steel plate for refining and chemical equipment, characterized in that, The composite steel plate has a thickness of 3-6mm for the cladding layer + 30-60mm for the base layer + 3-6mm for the cladding layer, and a width of 2000-4000mm. The chemical composition of the base layer, by weight percentage, is: C 0.12%-0.17%, Si 0.10%-0.30%, Mn 1.30%-1.60%, P ≤0.006%, S ≤0.002%, Ni 1.0%-1.5%, Ti 0.02%-0.06%, with the balance being Fe and unavoidable inclusions. The chemical composition of the cladding layer, by weight percentage, is: C 0.02%-0.04%, Si 0.30%-0.80%, Mn 1.20%-1.60%, P ≤0.010%, S ≤0.003%, Cr 16.0%-19.0%, Ni ≤0.003 ... 8.0%~13.0%, Ti 0.03%~0.10%, balance Fe and unavoidable inclusions; R at 500℃ m With a shear strength of ≥500MPa, 0% unbonded rate, and ≥370MPa, the SSC did not fracture after 720h at 500℃ and 0.5MPa standard atmospheric pressure. The ultrasonic flaw detection reached Level I, and the intergranular corrosion resistance of the cladding layer after being kept at 650℃ for 2h was qualified.

2. A method for preparing the double-sided composite steel plate for refining and chemical equipment as described in claim 1, characterized in that, This includes double-sided composite billet assembly—composite billet heating—rolling—hot straightening—slow cooling—heat treatment, wherein: Heating of composite billet: The double-sided composite billet is heated in a heating furnace to 1180-1230℃ for a total heating time of 4-6 hours. The composite billet is descaled before being rolled out of the furnace. Rolling: Rolling is completed entirely at high temperatures. The reduction in the first two rolling passes is controlled at 10~20mm, and the roll speed is 1.0~2.0m / s. The rolling process consists of 10~13 passes, with a final rolling temperature ≥900℃. After rolling, the steel plate is straightened and flattened by a hot straightener. After being removed from the line, it is stacked and slowly cooled at a temperature ≥400℃ for 24~36 hours. The specifications of the rolled composite plate are [(3~6)+(30~60)+(3~6)]mm×(2000~4000)mm×L. 板 mm; Heat treatment: Relieve post-rolling internal stress at 300~400℃, hold for 0.5~1.0h; normalizing at 900~950℃, hold for 1.0~1.5min / mm; relieve post-weld stress at 660~690℃, hold for 2.0~4.0h.

3. The method for preparing a double-sided composite steel plate for refining and chemical equipment according to claim 2, characterized in that, The double-sided composite preform assembly includes: combining a base preform and a composite material into a single-sided composite assembly by means of surface polishing, preform assembly, and explosive bonding; and then combining the other surface of the base preform of the single-sided composite assembly with another composite material by means of surface polishing, preform assembly, and explosive bonding to form a double-sided composite assembly. At this time, the acceptable bonding rate of the upper and lower bonding layers of the assembly is 40% to 60%, and the shear strength is 100 to 150 MPa.

4. The method for preparing a double-sided composite steel plate for refining and chemical equipment according to claim 3, characterized in that, The surface polishing includes polishing and grinding one surface of the blank and composite material, so that the surface is free of rust and oil stains, and exposes a metallic luster, with a surface roughness Ra of 15~25μm.

5. The method for preparing a double-sided composite steel plate for refining and chemical equipment according to claim 3, characterized in that, The assembly process includes: uniformly mixing an agent composed of iron powder and nickel powder in a ratio of 30:1 to 10:1 by mass, and spreading it evenly on the surface of the polished base blank with a thickness of 0.1 to 0.3 mm; the nickel powder has a purity of 99.9% or higher and a particle size of 2 to 10 μm; the iron powder has a purity of 99.9% or higher and a particle size of 2 to 10 μm; placing the composite material on the agent, aligning the four sides of the assembled blank, and fixing the four sides of the assembled blank by spot welding.

6. The method for preparing a double-sided composite steel plate for refining and chemical equipment according to claim 3, characterized in that, The explosion is performed by selecting 4 to 9 0.5m² holes on the surface of the composite material, based on the size and specifications of the composite blank. 2 A layer of explosives 10-30mm thick is laid over small areas, and explosives are used to connect the areas. The amount of explosives used is (10-15) kg / m². 2 The high-pressure pulse load generated by the explosion connects and fixes the base blank and composite metal.

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