A single-sided composite steel plate for refining units and its preparation method

Abstract

The present invention discloses a single-sided composite steel plate for refining units 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 0.30% - 0.60%, P ≤ 0.006%, S ≤ 0.002%, Mo 1.50% - 2.20%, Nb 0.02% - 0.06%; the chemical composition of the clad 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%, Mo 1.0% - 3.0%, Nb 0.03% - 0.10%. The preparation method includes single-sided composite blanking - combined blank heating - rolling - hot straightening - slow cooling - heat treatment, and a single-sided composite steel plate for refining units with a maximum plate width of 4000 mm and a maximum thickness of (6 + 60) mm can be obtained, meeting the requirements of high performance, long life, and large size single-sided composite steel plates for refining equipment, supporting the high-end metal materials required by China's petroleum refining industry, and facilitating the high-speed and large-scale development of refining equipment.

Description

Technical Field

[0001] The present invention relates to the field of metal materials, and particularly to a single-sided composite steel plate for refining units and a preparation method thereof. Background Art

[0002] The petroleum refining industry is one of the industries with the largest variety of products, the largest number of devices, and the most complex environment among many industrial fields. At high temperatures, various semi-finished products, finished products, and catalysts of oils, hydrocarbons, lipids, acids, and alkalis undergo chemical reactions in refining plants, posing a great test to the safe use of refining units. 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 huge usage, the construction and later maintenance costs of refining units are very high. Therefore, in recent years, using stainless steel composite materials instead of single stainless steel or corrosion-resistant alloys has become the development trend of refining equipment materials. However, due to different manufacturing capabilities and processes, metallurgical enterprises have varying degrees of restrictions and deficiencies in manufacturing composite plates, affecting production and comprehensive performance.

[0003] Before the present invention, the disclosed invention patent "Explosion Welding Method for 310S Austenitic Stainless Steel Composite Steel Plate" (Publication No. CN 101559525 A). From the disclosed invention content, it can be seen that the manufacturing method of this patent is an explosion bonding method. This method obtains a composite steel plate by simply treating the surfaces of the base material and the clad material and then performing explosion welding. Although the ultrasonic flaw detection is 100% qualified, due to uneven explosion force in the explosion composite method, the bonding effect is uneven, and the shear force at the bonding interface is small, affecting the service life and effect.

[0004] The disclosed invention patent "A Manufacturing Method for an Explosion Composite Plate" (Publication No. CN 105562920 A). From the disclosed invention content, it can be seen that this patent solves the problem of low bonding rate of the explosion composite plate by adding an interlayer. However, ultimately, this method is still a single explosion composite method. Although the interface bonding rate is improved, the shear strength at the bonding interface is not specifically reflected.

[0005] The disclosed invention patent "A Martensitic Stainless Steel Rolled Composite Steel Plate and a Manufacturing Method Thereof" (Publication No. CN108118252A). From the disclosed invention content, it can be seen that this patent uses a vacuum assembly method as the rolling raw material. As is well known, this method requires fine grinding of the surfaces of the base material and the clad material, and then vacuum pumping treatment. This method has cumbersome processes and requires vacuum pumping equipment, increasing the equipment cost.

[0006] The publicly disclosed invention patent "A High-Corrosion-Resistant Marine Composite Steel Plate and Its Manufacturing Method" (Publication No. CN111361235A). From the disclosed invention content, it can be seen that this patent is designed for composite steel plates used in shipbuilding. By using a four-layer symmetric vacuum billet assembling method as the rolling raw material, since it is necessary to clean the surfaces and sides of the four billets, it increases the cumbersome process procedures and also increases the cost of the vacuum pumping equipment.

[0007] The main deficiencies of the above-disclosed invention patent for composite steel plates are as follows: When using the explosion composite method to prepare composite steel plates for chemical equipment, the bonding strength is uneven and the bonding rate is low, which is not suitable for preparing large-width single-sided composite steel plates. In addition, explosion composite is likely to damage the original basic properties of the steel, which cannot be restored, affecting the safety and service life of the equipment during application; while for the composite plate using vacuum billet assembling, it is necessary to invest in vacuum pumping equipment, greatly increasing the production cost. Technologically, double-symmetric billet assembling is required, which is not suitable for producing large-thickness single-sided composite steel plates. Summary of the Invention

[0008] The purpose of the present invention is to provide a single-sided composite steel plate for refining units and its preparation method. By adopting a brand-new composition and production process, high-performance, long-life, and large-size single-sided composite steel plates required for refining equipment are developed to support the high-end metal materials needed for China's petroleum refining industry and contribute to the high-speed and large-scale development of refining equipment.

[0009] To solve the above problems, the technical solutions adopted in the present invention are as follows:

[0010] A single-sided composite steel plate for refining units, the chemical composition of the base layer by weight percentage is: C 0.12% - 0.17%, Si 0.10% - 0.30%, Mn 0.30% - 0.60%, P ≤ 0.006%, S ≤ 0.002%, Mo 1.50% - 2.20%, Nb 0.02% - 0.06%, and the balance is Fe and inevitable inclusions; the chemical composition of the clad 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%, Mo 1.0% - 3.0%, Nb 0.03% - 0.10%, and the balance is Fe and inevitable inclusions.

[0011] Furthermore, the thickness of the composite steel plate is: clad layer 3 - 6 mm + base layer 30 - 60 mm, and the width is: 2000 - 4000 mm.

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

[0013] Furthermore, the clad steel plate did not fracture during SSC for 720 h at 500 °C and 0.5 MPa standard atmospheric pressure, and the ultrasonic flaw detection reached Grade I.

[0014] Furthermore, the corrosion resistance of the cladding layer of the clad steel plate at 650 °C for 2 h was qualified.

[0015] A preparation method of a single-sided clad steel plate for refining units includes single-sided composite billet forming - combined billet heating - rolling - hot straightening - slow cooling - heat treatment, where:

[0016] Heat the single-sided composite billet in a heating furnace to 1180 - 1230 °C, with a total heating duration of 4 - 6 h, and descale the combined billet before rolling out of the furnace.

[0017] Use the asynchronous rolling method for rolling, where the composite material is located on the upper layer of the billet, the roll speed of the upper working roll is 1.5 - 2.5 m / s, and the roll speed of the lower working roll is 0.8 - 1.5 m / s; all rolling is completed at a high temperature stage, the reduction ratio in the first two rolling passes is controlled at 5% - 8%, the rolling process is divided into 10 - 13 passes, and the final rolling temperature ≥ 900 °C; after rolling, the steel plate is straightened by a hot straightening machine to flatten the plate shape, and after being taken off the production line, it is stacked for slow cooling, with the slow cooling temperature ≥ 450 °C and the slow cooling time of 24 - 36 h. The specifications of the rolled clad plate are [(3 - 6)+(30 - 60)] mm × (2000 - 4000) mm × L 板 mm;

[0018] The heat treatment temperature for eliminating internal stress after rolling is 300 - 400 °C, with a holding time of 0.5 - 1.0 h; the normalizing heat treatment temperature is 900 - 950 °C, with a holding time of 1.0 - 1.5 min / mm; the temperature for eliminating stress after welding is 660 - 690 °C, with a holding time of 2.0 - 4.0 h.

[0019] Furthermore, the single-sided composite billet includes base billet, composite material specification design - surface polishing - billet forming - explosive bonding, where: Base billet, composite material specification design: The prepared specification of the base billet is (100 - 300) mm thick × (2000 - 4000) mm wide × L 坯 mm, corresponding to the prepared specification of the composite material (10 - 30) mm thick × (2000 - 4000) mm wide × L 材 mm, L 坯 = L 材 .

[0020] Furthermore, surface polishing: Polish and grind one surface of the base billet and the composite material, with no rust and oil stain defects on the surface, showing metallic luster, and the surface roughness Ra is 15 - 25 μm.

[0021] Further, blank assembly: The mixture composed of iron powder and molybdenum powder is uniformly mixed in proportion. The mass ratio of iron powder to molybdenum powder is 30:1 to 10:1, and it is evenly spread on the surface of the polished base blank with a thickness range of 0.1 - 0.3 mm; the purity of molybdenum powder is above 99.9%, and the particle size is 2 - 10 μm; the purity of iron powder is above 99.9%, and the particle size is 2 - 10 μm; the composite material is placed on the mixture, the four sides of the combined blank are aligned, and the four sides of the combined blank are fixed by spot welding.

[0022] Further, explosive bonding: According to the size specifications of the base blank, 4 - 9 small areas of 0.5 m 2 are selected on the surface of the composite material to lay a layer of explosive with a thickness of 10 - 30 mm. The areas are connected by explosives, and the explosive dosage is (10 - 15) kg / m 2 . Through the high-pressure pulse load generated by the explosion, the base blank and the composite material metal are connected and fixed to form a raw material combined blank before rolling. At this time, the acceptable bonding rate of the combined blank is 40% - 60%, and the shear strength is 100 - 150 MPa.

[0023] The present invention has the following beneficial effects compared with the prior art:

[0024] 1. Through the solution strengthening and carbide precipitation strengthening effects of adding Mn, Mo, and Nb alloying elements in the base layer of the present invention, the basic strength, especially the high-temperature strength, high-temperature oxidation resistance, and forming performance of the composite steel plate are ensured. The cladding layer uses Cr, Ni, Nb, and Mo alloying elements to ensure excellent corrosion resistance of the cladding layer.

[0025] 2. By using the method of preparing the combined blank with a small amount of explosives, the bonding rate only needs to be 40% - 60%, and the shear strength at the bonding part only needs to be 100 - 150 MPa. The advantages of preparing this combined blank are less environmental pollution generated by the explosion, flexible blank assembly specifications, no need for expensive equipment investment, and low cost.

[0026] 3. The present invention can obtain a thick-specification composite steel plate with a cladding layer (3 - 6 mm) + a base layer (30 - 60 mm), the width can reach 2000 - 4000 mm, R m ≥500 MPa, unbonding rate 0%, shear strength ≥370 MPa at 500 °C. At 500 °C and 0.5 MPa standard atmospheric pressure, no fracture occurs during 720 h of SSC, the ultrasonic flaw detection reaches Grade I, and the intergranular corrosion resistance of the cladding layer is qualified after heat preservation at 650 °C for 2 h, which can meet the requirements of the complex application environment of refining equipment. Specific embodiments

[0027] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] A single-sided composite steel plate for refining equipment, wherein the chemical composition of the base layer by weight percentage is: C 0.12% - 0.17%, Si 0.10% - 0.30%, Mn 0.30% - 0.60%, P ≤ 0.006%, S ≤ 0.002%, Mo 1.50% - 2.20%, Nb 0.02% - 0.06%, and the balance is Fe and unavoidable inclusions. The chemical composition of the clad 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%, Mo 1.0% - 3.0%, Nb 0.03% - 0.10%, and the balance is Fe and unavoidable inclusions.

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

[0030] C: In the present invention, C is the main element to improve the strength of the base layer of the composite plate. By solid solution strengthening the strength of the matrix, it ensures the room temperature and high temperature strength of the base layer steel plate. However, too high a carbon content is not conducive to welding and processing performance. Therefore, the C content range in the present invention is set to 0.12% - 0.17%.

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

[0032] Mn: In the present invention, due to the relatively small addition amount of the deoxidizer Si, 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 matrix strength. However, Mn is the main factor affecting temper brittleness and needs to be strictly controlled in the present invention. Therefore, the Mn content range in the present invention is set to 0.30% - 0.60%.

[0033] S and P are harmful elements in the steel. To ensure the purity of the steel quality and comprehensive performance indicators, they must be strictly controlled. Therefore, it is limited to S ≤ 0.002% and P ≤ 0.006%.

[0034] Mo: In the present invention, adding molybdenum not only plays a role in solid solution strengthening and precipitation strengthening, but also improves the high-temperature tempering stability, which can ensure the room-temperature strength and high-temperature strength of the composite steel plate. Therefore, the Mo content in the present invention is controlled within the range of 1.50% to 2.20%.

[0035] Nb: It is a strong carbide and nitride forming element, forming a dispersion of precipitate phases at the grain boundaries, which significantly hinders the slip and climb of dislocations, thus having a good high-temperature strengthening effect. At the same time, its grain refinement effect can reduce the overheating sensitivity and temper brittleness of the steel. Therefore, the Nb content range in the present invention is set at 0.02% to 0.06%.

[0036] Reasons for the chemical composition design of the clad plate:

[0037] C: Carbon can significantly improve the strength of the clad layer and stabilize austenite. However, excessive carbon will combine with chromium to form chromium carbides, resulting in a decrease in the solid-solution chromium content and seriously affecting the corrosion resistance of the clad metal. Therefore, the C content range in the present invention is set at 0.02% to 0.04%.

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

[0039] Mn: In the present invention, Mn is a solid solution strengthening element, which improves the strength of the clad layer and increases the shear strength at the joint. At the same time, manganese can form oxides with chromium to form a dense oxide film to prevent the erosion of oxygen, water and other media, thereby improving the corrosion resistance of the clad layer. However, excessive Mn affects the temper brittleness of the clad layer, and the present invention should not add it in excess. Therefore, the Mn content range in the present invention is set at 1.20% to 1.60%.

[0040] S, P: As harmful elements in steel, in order to ensure the purity of the steel quality and improve the steel quality performance, they must be strictly controlled. Therefore, it is limited that S ≤ 0.003% and P ≤ 0.010%.

[0041] Cr: Adding the alloying element chromium to the clad plate mainly utilizes the corrosion resistance characteristics of chromium. In an oxidizing medium, a firm and dense chromium oxide film is formed on the surface of the steel to protect the steel plate substrate; chromium dissolved in the steel can significantly increase the electrode potential of the steel, reducing the electrochemical corrosion caused by different electrode potentials. Therefore, the Cr content in the present invention is controlled within the range of 16.0% to 19.0%;

[0042] Ni: is an austenite-forming 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 8.0% to 13.0%;

[0043] Mo: has a solid solution strengthening effect on ferrite and can also improve the stability of carbides. The formed carbides can improve the hydrogen corrosion resistance of steel under high temperature and high pressure. In addition, molybdenum increases the pitting corrosion resistance of the composite layer and improves the crevice corrosion resistance. Therefore, the present invention controls the Mo content to 1.0% to 3.0%;

[0044] Nb: stabilizes the C element in the steel to form niobium carbide, preventing excessive combination of C and Cr, which would lead to chromium depletion at the grain boundaries and intergranular corrosion. Therefore, the present invention controls the Nb content to 0.03% to 0.10%.

[0045] A method for preparing a single-sided composite steel plate for refining equipment is as follows:

[0046] Process path: single-sided composite billet assembly (base billet, composite material specification design - surface polishing - billet assembly - explosive bonding) - combined billet heating - rolling - hot straightening - slow cooling - heat treatment - flaw detection - inspection and testing.

[0047] 1) Reasonably design the specifications of the base blank and composite materials. The base blank preparation specifications are (100-300mm) thickness × (2000-4000mm) width × L 坯 mm, corresponding to the composite material preparation specifications (10-30mm) thickness × (2000-4000mm) width × L 材 mm, L 坯 =L 材 .

[0048] 2) Polish and grind the contact surface between the base blank and the composite material to ensure that there is no impurity defects such as rust and oil stains on the surface, and the metallic luster is exposed. The surface should not be too smooth to prevent the metal atoms from sliding during the explosion, without a fulcrum, and poor bonding. The roughness Ra is 15 to 25 μm.

[0049] 3) A mixture of iron powder and molybdenum powder is uniformly mixed in a mass ratio of 30:1 to 10:1. The mixture is evenly spread on the polished surface of the base blank to a thickness of 0.1 to 0.3 mm. The molybdenum powder must be at least 99.9% pure and have a particle size of 2 to 10 μm. The iron powder must be at least 99.9% pure and have a particle size of 2 to 10 μm. The composite material is placed on the mixture, the four sides of the composite blank are aligned, and the four sides of the composite blank are fixed by spot welding to prevent the composite material from moving during the explosion.

[0050] 4) According to the size of the steel billet, select 4 to 9 0.5m 2Lay a layer of explosive with a thickness of 10 - 30 mm in a small area. Connect the areas with explosives. The explosive dosage is (10 - 15) kg / m 2 , and through the high - pressure pulse load generated by the explosion, connect and fix the base blank and the clad metal to form a raw material combination (combined blank) before rolling. At this time, the acceptable bonding rate of the combined blank is 40 - 60%, and the shear strength is 100 - 150 MPa.

[0051] 5) Heat the exploded single - sided composite combined blank in a heating furnace to 1180 - 1230 °C for a total heating duration of 4 - 6 h. Through the heating in the high - temperature stage, the gas at the composite interface is fully discharged, and the active atoms of the base blank and the clad material diffuse and migrate with each other at the interface to form a metallurgical bond. Scale removal is carried out before the combined blank is rolled out of the furnace. Since the chemical compositions of the upper and lower layers of the rolled piece are different, there are differences in the deformation resistance during rolling. Therefore, an asynchronous rolling method needs to be adopted for rolling. Among them, the clad material is located on the upper layer of the combined blank. The rolling speed of the upper working roll is 1.5 - 2.5 m / s, and the rolling speed of the lower working roll is 0.8 - 1.5 m / s. The rolling is all completed in the high - temperature stage. Since the bonding interface is close to the upper layer of the combined blank, the reduction ratio in the first two rolling passes should not be too large, mainly to ensure sufficient bonding. The reduction ratio is controlled at 5% - 8% to prevent cracking of the bonding layer due to excessive deformation. The rolling process is divided into 10 - 13 passes, and the finishing rolling temperature ≥ 900 °C. After rolling, the steel plate is straightened by a hot straightening machine to level the plate shape. After being taken off the production line, it is stacked and slowly cooled. The slow - cooling temperature ≥ 450 °C, and the slow - cooling time is 24 - 36 h. The specifications of the rolled composite plate are [(3 - 6)+(30 - 60)] mm × (2000 - 4000) mm × L 板 mm.

[0052] 6) There is a certain amount of internal stress remaining at the bonding interface of the rolled composite plate, which needs to be eliminated by heat treatment. The heat treatment temperature for eliminating the internal stress after rolling is 300 - 400 °C, and the holding time is 0.5 - 1.0 h; The strength of the rolled composite steel plate is relatively high, and the plasticity and toughness are poor, which cannot meet the mechanical property requirements of the refining device. It is necessary to improve the performance through further normalizing heat treatment. Therefore, the normalizing temperature of the present invention is 900 - 950 °C, and the holding time is 1.0 - 1.5 min / mm; Finally, the final mechanical properties of the composite plate are inspected through the heat treatment process of eliminating the stress after welding. The temperature for eliminating the stress after welding is 660 - 690 °C, and the holding time is 2.0 - 4.0 h. Finally, a single - sided refining - used composite steel plate with a bainite tempered structure as the base layer and an austenite structure as the clad layer is obtained.

[0053] The following further describes the present invention in detail with specific embodiments.

[0054] Examples are used to specifically illustrate the content of the present invention. These examples 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 examples of the present invention, Table 2 Preparation process parameters of the combined billets of the examples of the present invention, Table 3 Rolling and heat treatment process parameters of the examples of the present invention, Table 4 Final effects of the microstructure and properties of the examples of the present invention, Table 5 Internal and external quality of the examples of the present invention, Table 6 SCC resistance test results of the examples of the present invention under high temperature and high pressure, Table 7 Immersion test of the examples of the present invention in a 5.0% NaCl solution at 100°C for 720 h.

[0055] Table 1 Chemical composition (wt%) of the examples of the present invention

[0056]

[0057] Table 2 Preparation process parameters of the combined billets of the examples of the present invention

[0058]

[0059]

[0060] Table 3 Rolling and heat treatment process parameters of the examples of the present invention

[0061]

[0062] Table 4 Mechanical properties of the examples of the present invention

[0063]

[0064] Table 5 Internal and external quality of the examples of the present invention

[0065]

[0066]

[0067] Table 6 SCC resistance test results of the examples of the present invention under high temperature and high pressure

[0068] Example Under the test conditions of a temperature of 500 °C and a pressure of 0.5 MPa, the loading time was 720 h 1 Did not break 2 Did not break 3 Did not break 4 Did not break 5 Did not break 6 Did not break

[0069] Table 7 Immersion test of the examples of the present invention in a 5.0% NaCl solution at 100°C for 720 h

[0070]

[0071] According to the above results, it can be concluded that the thick composite steel plate with a clad layer (3 mm - 6 mm) + base layer (30 mm - 60 mm) provided by the present invention has a width of up to 2000 - 4000 mm and an R at 500°C m≥500 MPa, unbonded rate 0%, shear strength ≥370 MPa. At 500 °C and 0.5 MPa standard atmospheric pressure, no fracture occurred during 720 h of SSC, ultrasonic flaw detection reached Grade I, and the intergranular corrosion performance was qualified after the cladding layer was sensitized at 650 °C for 2 h.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements 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 single-sided composite steel plate for refining equipment, characterized in that The chemical composition of the base layer by weight percentage is: C 0.12% - 0.17%, Si 0.10% - 0.30%, Mn 0.30% - 0.60%, P ≤0.006%, S ≤0.002%, Mo 1.50% - 2.20%, Nb 0.02% - 0.06%, and the balance is Fe and inevitable inclusions; the chemical composition of the clad 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%, Mo 1.0% - 3.0%, Nb 0.03% - 0.10%, and the balance is Fe and inevitable inclusions; the R at 500°C m ≥500 MPa, unbonded rate 0%, shear strength ≥370 MPa; at 500°C and 0.5 MPa standard atmospheric pressure, no fracture occurred in the SSC for 720 h, and the ultrasonic flaw detection reached Grade I; the clad layer passed the intergranular corrosion resistance test at 650°C for 2 h of heat preservation.

2. The one-sided composite steel plate for refining equipment according to claim 1, wherein The thickness of the clad steel plate is: 3 - 6 mm for the clad layer + 30 - 60 mm for the base layer, and the width is: 2000 - 4000 mm.

3. A method for preparing a single-sided composite steel plate for a refining unit according to claim 1 or 2, characterized in that, It includes single-sided composite billet assembling - combined billet heating - rolling - hot straightening - slow cooling - heat treatment, where: Heat the single-sided composite combined billet in a heating furnace to 1180 - 1230 °C, with a total heating duration of 4 - 6 h. Scale removal is carried out before the combined billet is taken out of the furnace for rolling. The rolling is carried out by asynchronous rolling method, where the composite material is located in the upper layer of the billet assembly. The roll speed of the upper working roll is 1.5 - 2.5 m / s, and the roll speed of the lower working roll is 0.8 - 1.5 m / s. The rolling is completed entirely at the high temperature stage. The reduction rate in the first two passes of rolling is controlled at 5% - 8%. The rolling process is divided into 10 - 13 passes, and the finishing rolling temperature is ≥900 °C. After rolling, the steel plate is straightened by a hot straightening machine to flatten the plate shape. After being taken off the production line, it is stacked for slow cooling. The slow cooling temperature is ≥450 °C, and the slow cooling time is 24 - 36 h. The specifications of the rolled composite plate are [(3 - 6)+(30 - 60)] mm × (2000 - 4000) mm × L 板 mm; For the heat treatment to eliminate internal stress after rolling, the temperature is 300 - 400 °C, and the holding time is 0.5 - 1.0 h; for normalizing heat treatment, the temperature is 900 - 950 °C, and the holding time is 1.0 - 1.5 min / mm; for eliminating stress after welding, the temperature is 660 - 690 °C, and the holding time is 2.0 - 4.0 h.

4. The preparation method of the single-sided composite steel plate for refining equipment according to claim 3, characterized in that, The single-sided composite billet assembling includes base billet, clad material specification design - surface polishing - billet assembling - explosive bonding, where: Base blank and composite material specification design: Base blank preparation specification (100~300 mm) thick × (2000~4000 mm) wide × L 坯 mm, corresponding to composite material preparation specification (10~30 mm) thick × (2000~4000 mm) wide × L 材 mm, L 坯 =L 材 .

5. The preparation method of the single-sided composite steel plate for refining equipment according to claim 4, characterized in that Surface polishing: Polish and grind one surface of the base billet and the clad material. The surface has no rust and oil stain defects, showing metallic luster, and the surface roughness Ra is 15 - 25 μm.

6. The preparation method of the single-sided composite steel plate for refining equipment according to claim 4, characterized in that Billet assembling: Uniformly mix the mixture composed of iron powder and molybdenum powder in proportion. The mass ratio of iron powder to molybdenum powder is 30:1 - 10:

1. Uniformly spread it on the surface of the polished base billet, with a thickness range of 0.1 - 0.3 mm; the purity of molybdenum powder is above 99.9%, and the particle size is 2 - 10 μm; the purity of iron powder is above 99.9%, and the particle size is 2 - 10 μm; Place the clad material on the mixture, align the four sides of the combined billet, and fix the four sides of the combined billet by spot welding.

7. The preparation method of the single-sided composite steel plate for refining equipment according to claim 4, characterized in that Explosive bonding: According to the size specifications of the base blank, select 4 to 9 small areas of 0.5 m on the surface of the composite material and lay a layer of explosive with a thickness of 10 to 30 mm. Connect the areas with explosives. The amount of explosive used is (10 - 15) kg / m 2 , and through the high-pressure pulse load generated by the explosion, connect and fix the base blank and the composite material metal to form a combined blank as the raw material before rolling. At this time, the acceptable bonding rate of the combined blank is 40% - 60%, and the shear strength is 100 - 150 MPa. 2 ​

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