High-strength double-sided aluminum-coated plate strip and production method thereof

Abstract

The invention relates to a high-strength double-sided aluminum-coated plate strip and a production method thereof, the aluminum-coated plate strip is composed of a substrate, an upper aluminum-coated layer and a lower aluminum-coated layer, and the substrate comprises the following chemical components in percentage by weight: 0.002-0.05% of C, less than or equal to 0.01% of Si, 0.55-1.5% of Mn, less than or equal to 0.02% of P, less than or equal to 0.008% of S, less than or equal to 0.005% of Al, 0.003-0.010% of N, 0.004-0.0100% of O, 0.0005-0.0020% of B and the balance of Fe and other inevitable impurities. The high-strength double-sided aluminum-coated plate strip not only has the strength of steel, but also has the characteristics of heat dissipation, corrosion resistance, light weight and attractive appearance of aluminum, and has good aluminum coating performance and excellent deep drawing performance; the yield strength is 300-400 MPa, the tensile strength is 450-550 MPa, the elongation A is larger than or equal to 22%, the width of the aluminum-coated plate strip can reach 700-1800 mm, the requirements for good steel-aluminum bonding performance and wide width are met, and the aluminum-coated plate strip is suitable for manufacturing of radiators, kitchen ware, household appliance panels and corrosion-resistant structural parts, and coating is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of low alloy steel manufacturing, and particularly relates to a high-strength double-sided aluminum-coated plate strip and a production method thereof. BACKGROUND

[0002] With the increasing requirements for appearance, corrosion resistance, electrical conductivity, heat dissipation and forming performance, a single material is difficult to meet the performance requirements in multiple aspects. A composite plate prepared by selecting multiple metal materials through various processes combines the advantages of multiple metals, thereby meeting the needs of engineering applications. Currently, common composite plate strips include copper-coated, aluminum-coated or titanium-steel, stainless steel-steel composite materials. The aluminum-coated plate strip is a steel-aluminum composite strip formed by coating an aluminum strip on the surface of a steel strip. In terms of structure, it has a copper-aluminum-steel structure or an aluminum-steel-aluminum structure. The aluminum-coated plate strip has the strength of steel, and at the same time has the characteristics of good heat dissipation, corrosion resistance, light weight and appearance of aluminum, and significantly reduces the cost. It has been widely used in the fields of radiator fins, corrosion-resistant components, household appliance panels and cookware. From the perspective of improving corrosion resistance, the existing weathering steel composition system needs to add many corrosion-resistant alloys; at the same time, in order to achieve high strength and weight reduction, some strengthening elements such as Ti and Nb need to be added, which significantly increases the cost. At the same time, weathering steel belongs to overall corrosion resistance, and corrosion mainly occurs on the surface. The many corrosion-resistant alloys added in the interior of the steel plate cannot play a role, which is also a waste of resources. Al, as a corrosion-resistant metal, also has excellent atmospheric corrosion resistance, so the aluminum-coated plate strip is not only beautiful and has good heat dissipation, but also has excellent corrosion resistance.

[0003] In the field of clad plate strips, there are many related patents for copper-coated and aluminum-coated products.

[0004] For example, Chinese Patent Publication No. CN101660087 discloses "an aluminum-steel-aluminum composite material and a preparation method thereof". The aluminum and steel are surface treated and then cold-rolled into high-precision aluminum strips and steel strips, respectively. Then, the aluminum-steel-aluminum composite strip is cold-rolled again into a high-precision aluminum-steel-aluminum composite strip, and then annealed at a temperature of 650-850°C for 1-4 hours. Since the melting point of aluminum is about 640°C, annealing at such a high temperature seriously deteriorates the interfacial bonding strength of steel and aluminum.

[0005] Chinese Patent Publication No. CN102019727 discloses "an aluminum-coated steel strip for coolers, a preparation method thereof and a steel strip and aluminum alloy strip used therein". The patent mainly relates to an aluminum-coated steel strip for heat dissipation and a base plate.

[0006] Chinese patent publication No. CN114248508B discloses "an aluminum-coated plate strip for kitchen utensils and its production method", which relates to an aluminum-coated plate strip with a tensile strength ≥320 MPa and an elongation ≥28%. Its covering process is a conventional room temperature cold rolling covering process, and after covering rolling, it needs to be annealed in the range of 500-560℃ to obtain the required steel-aluminum bonding performance.

[0007] Chinese patent publication No. CN112877636A discloses "hot-dip aluminum-coated steel sheet with excellent corrosion resistance and its manufacturing method", which relates to a hot-dip aluminum-coated steel sheet with excellent corrosion resistance. Although the aluminum-coated steel sheet described in this patent also uses a hot-dip process to achieve an aluminum coating, the substrate used contains: 0 < C ≤ 0.3%, 0 < Si ≤ 1.0%, 0 < Mn ≤ 2.0%, P ≤ 0.2%, S ≤ 0.1%, 0.001 ≤ Al ≤ 0.3%, and needs to add Nb and Ti with a total of not more than 0.5%, mainly for the manufacture of automobile fuel tanks. The alloy content of the substrate described in this patent is high, and there is a clear iron-aluminum compound layer at the steel-aluminum interface, with poor steel-aluminum bonding performance, which cannot meet the requirements for the manufacture of radiator fins.

[0008] In addition, the aluminum-coated plate strips produced by existing processes are mostly less than 500mm in width, mainly used for the manufacture of radiators and cookware, and are difficult to meet the demand for wide aluminum-coated plate strips in the corrosion-resistant field.

[0009] From the comparison results, the current aluminum-coated material related patent technologies mainly use cold rolling covering process for production, with limited width, and after aluminum-coated rolling, annealing treatment is needed to improve the interface bonding strength and meet the subsequent cold forming processing requirements; while the aluminum-coated plate strips produced by the aluminum plating process have iron-aluminum compounds at the interface, poor steel-aluminum bonding performance, and not enough aesthetic appearance. SUMMARY

[0010] The purpose of the present application is to provide a high-strength double-sided aluminum-coated plate strip and its production method, which has both the strength of steel and the heat dissipation, corrosion resistance, lightness, and aesthetic properties of aluminum, as well as good aluminum-coating performance and excellent drawing performance, with a yield strength of 300-400 MPa, a tensile strength of 450-550 MPa, and an elongation A ≥ 22%, and the width of the aluminum-coated plate strip can reach 700-1800 mm, meeting the requirements for good steel-aluminum bonding performance and wide width, and being suitable for the manufacture of radiators, kitchen utensils, household appliance panels, and corrosion-resistant structural parts, reducing painting.

[0011] To achieve the above-mentioned purpose, the technical solution of the present application is:

[0012] A high-strength double-sided aluminum-clad strip is composed of a substrate and aluminum layers on the upper and lower surfaces of the substrate, and the substrate has a chemical composition by weight percentage of C: 0.002-0.05%, Si: ≤0.01%, Mn: 0.55-1.5%, P: ≤0.02%, S: ≤0.008%, Al: ≤0.005%, N: 0.003-0.010%, O: 0.004-0.0100%, and B: 0.0005-0.0020%, and the balance includes Fe and other inevitable impurity elements.

[0013] Further, the balance of the substrate composition includes Fe and other inevitable impurity elements.

[0014] Still further, the single-sided aluminum layer of the aluminum-clad strip has a thickness of 10 μm or more, preferably, the single-sided aluminum layer has a thickness of 40-80 μm.

[0015] Preferably, the aluminum-clad strip has a width of 700-1800 mm.

[0016] The aluminum-clad strip has a yield strength of 300-400 MPa, a tensile strength of 450-550 MPa, and an elongation A of ≥22%.

[0017] The composition of the substrate is designed simply as C-Mn design, reducing the use of valuable alloy elements such as Cu, Ni, Cr, Mo, Nb, Ti, etc.

[0018] C is a main strengthening element in steel, and increases the yield strength through solid solution strengthening. Too high C reduces the elongation, and is not conducive to the subsequent stamping, drawing and other processing properties of the material; meanwhile, high C is prone to segregate at dislocation defects, which is not conducive to the surface quality and steel-aluminum bonding performance. The present application limits the C content to 0.002-0.05%.

[0019] Si is a deoxidizing element and a solid solution strengthening element, which increases the yield strength and reduces the elongation. Although appropriate Si is beneficial to improve the steel-aluminum interface bonding performance, it will weaken the inhibitory effect of O (oxygen) on the formation of brittle compound layer at the steel-aluminum interface. Therefore, the upper limit of Si content is controlled to 0.01%.

[0020] Mn is also a common strengthening element in steel, which increases the yield strength through solid solution strengthening and reduces the elongation; appropriate Mn can combine with S in steel to form MnS, reducing the hot brittleness of the steel, but too high Mn hinders the recovery of the structure and inhibits the growth of recrystallized grains, reducing the strength of γ texture (ND∥<111>), which is not conducive to the stamping forming of the steel plate, and increases the cost. Therefore, the Mn content is controlled to 0.55-1.50%.

[0021] Higher P causes the "cold brittleness" of the steel, reduces the plasticity and impact toughness, and makes the welding performance and cold bending performance of the steel worse, and higher P is not conducive to the steel aluminum interface bonding, so the content of P in the steel should be reduced as much as possible, and the application requires that the content of P is controlled to be ≤0.02%.

[0022] S is not conducive to the performance of the steel, can easily cause the "hot brittleness" of the steel, reduce the low temperature toughness of the steel, and at the same time, deteriorate the aluminum performance. The addition of Mn can form MnS with S, and the increase of the ratio of Mn / S can improve the hot ductility, and it is required that the content of S is controlled to be ≤0.008%.

[0023] Al is an important deoxidizing element of the steel, but higher Al is easy to diffuse to the steel aluminum bonding interface, and deteriorate the interface bonding strength. Therefore, the content must be controlled within a certain range, and the application requires that the content of Al is limited to 0.005% as the upper limit.

[0024] B is a very active element in the steel, which is easy to form compounds with C and N. At the same time, B is easy to segregate at the austenite grain boundary and dislocation, so as to inhibit the segregation of other interstitial atoms at this place. Moreover, the segregation of B does not hinder the movement of dislocation, so that the strain is uniform. However, too high B can promote the increase of quenching depth, which leads to too high strength and reduces the stamping performance, so the content of B is limited to 0.0005-0.002%.

[0025] N can form AlN particles with Al in the steel, thereby playing the role of binding Al and limiting the diffusion of Al in the steel; at the same time, N is similar to C, which is easy to segregate at the dislocation to form a kossel cloud, resulting in strain concentration, so that the aluminum clad material produces uneven strain in the processing process, affects the surface quality, and too high N also deteriorates the impact toughness, so the application controls the content of N to be 0.003-0.010%.

[0026] Oxygen (O) element can inhibit the adverse effect of Al element in the steel on the aluminum clad performance, so it is required to add a certain amount of O element. However, too high oxygen will produce subcutaneous bubbles, loose and other defects, and aggravate the hot brittleness of sulfur. In the solidification process of the steel, oxygen will be precipitated in the form of oxide, which reduces the plasticity, impact toughness and other properties of the steel. Moreover, too high content of oxygen reacts with the protective slag during casting process, and erodes the water gap, which leads to low pouring furnace number, and increases the production cost. Therefore, the application controls the content of O to be 0.004-0.010%.

[0027] The base plate steel of the aluminized plate strip requires good plasticity to meet the steel-aluminum cladding rolling, and meets the cold forming requirements on the basis of ensuring the aluminizing performance. By controlling the content of Si, Al and O and N in the steel, the formation of brittle compounds at the steel-aluminum interface is inhibited. The combination of 0.003-0.01% N and residual Al in the steel limits the diffusion of Al in the steel, further improving the aluminizing performance. The content of C is limited in the range of 0.002-0.05%, which avoids the deterioration of the steel-aluminum bonding performance, and the addition of 0.0005-0.002% B limits the distribution of C and N atoms at the grain boundary, reduces the segregation of C and N at dislocations, and improves the surface quality and cold forming performance.

[0028] In the present application, Mn is used as the main strengthening element. Although 0.002-0.05% C is added in the present application, it is difficult to control the yield strength above 300 MPa with less than 0.05% C, and adding more C will consume O in the steel, resulting in a decrease in effective O content, which is not conducive to the improvement of the steel-aluminum bonding performance. Although P is used as a strengthening element in IF steel, too high P is not conducive to the steel-aluminum bonding performance, and it is also difficult to meet the yield strength above 300 MPa. Mn has solid solution strengthening effect in the steel without damaging the steel-aluminum bonding performance. Therefore, 0.55-1.5% Mn is used in combination with C in the present application to obtain the required strength through solid solution strengthening.

[0029] In summary, by using the above-mentioned required component system, the required aluminized base plate steel can be obtained.

[0030] The production method of the high-strength double-sided aluminized plate strip of the present application comprises the following steps:

[0031] 1) annealing and hot plating

[0032] After pickling, the base plate is annealed and then enters the plating pool for hot plating; the annealing temperature is 610-630℃, the annealing time is 60-88s; the temperature of the aluminum liquid is 610-628℃, the temperature of the base plate entering the plating pool is 605-620℃, which is 2-10℃ lower than the temperature of the aluminum liquid;

[0033] 2) warm rolling

[0034] The aluminized plate strip after hot dip aluminizing is directly rolled in the rolling mill to obtain the finished double-sided aluminized plate strip with the required thickness; the deformation amount of the first pass is ≥45%; single pass or multiple passes are selected for rolling, and the total deformation amount is required to be ≥60% when multiple passes are used;

[0035] 3) coiling

[0036] The aluminized plate strip after rolling is immediately water-cooled, and the cooling rate is controlled to be more than 20℃ / s, and the water-cooled aluminized plate strip is coiled at a temperature in the range of 460-509℃.

[0037] The present application is produced by hot dip coating aluminum + warm rolling process. The strip steel (substrate, the composition is as described above) after annealing (preferably using continuous annealing) into the aluminum pool double-sided aluminum coating, then warm rolling into aluminum-coated roll and heat preservation, omitting the subsequent annealing process of the existing cold-rolled clad process to prepare aluminum-coated plate, the front surface of the aluminum-coated does not need to be polished.

[0038] The strip steel to be coated needs to be pickled to remove the surface oxide scale and stains before entering the annealing furnace. The substrate after pickling is annealed and then enters the aluminum plating pool for hot plating. The purpose of annealing is to increase the surface temperature of the substrate, avoid large temperature fluctuations in the plating pool due to low substrate temperature, and avoid uneven thickness of the strip steel surface coating. The annealing temperature is limited to 610-630℃, and the annealing time is 60-88s. High annealing temperature or long annealing time increases energy consumption and production cost, and high temperature easily induces the reaction of iron in the substrate and aluminum in the plating solution, promoting the formation of iron-aluminum compounds. The phases of iron and aluminum compounds are all brittle phases, and the formation of iron-aluminum compounds at the steel-aluminum interface will deteriorate the interfacial bonding strength.

[0039] In order to obtain good steel-aluminum bonding performance and the required aluminum layer thickness, the temperature of the aluminum plating solution and the substrate entering temperature are limited, the aluminum liquid temperature is controlled to 610-628℃, and the temperature of the substrate entering the aluminum plating pool is 605-620℃, which is 2-10℃ lower than the aluminum liquid temperature. Iron and aluminum easily form brittle iron-aluminum compound phases at high temperatures, such as FeAl, Fe2Al5, FeAl3, etc.; if the temperature of the aluminum plating solution or the substrate is too high, iron-aluminum compounds will be formed at the steel-aluminum interface during the aluminum plating process, which will deteriorate the steel-aluminum bonding strength, and even cause the steel and aluminum to separate during subsequent use. On the other hand, if the temperature of the aluminum plating solution is too low, the flowability of the aluminum plating solution will be reduced, resulting in a low surface aluminum layer thickness, and increasing the resistance of the strip steel passing through the aluminum plating solution.

[0040] The aluminum-coated strip after hot dip aluminum coating is directly rolled into the rolling mill to obtain the required thickness of the finished double-sided aluminum-coated material. The rolling mill can be single-stand, double-stand or multi-stand. In order to ensure good steel-aluminum bonding performance, the first pass deformation is required to be ≥45%. The bonding of the surface aluminum layer and the strip steel is achieved by the adhesion and diffusion of iron and aluminum atoms at high temperature, as well as the physical bonding through mechanical interlocking. During the deformation process, the aluminum layer and the substrate surface are extended and expose a large number of fresh surfaces, which are easy to achieve local metallurgical bonding between the two, and the deformation promotes the mechanical interlocking of the two, finally achieving good bonding of steel and aluminum. When the deformation is too low, the bonding of steel and aluminum is only the adhesion of liquid aluminum in the plating pool to the steel and aluminum through physical adsorption to achieve the initial adhesion of the two, and the interfacial bonding strength is limited.

[0041] The deformation amount of the pass can be selected as single pass or multiple passes, and the total deformation amount is required to be greater than or equal to 60% when multiple passes are adopted. The thickness of the single aluminum layer of the finished aluminum-clad material is greater than or equal to 10 microns, and preferably 40-80 microns. The aluminum-clad material after rolling is water-cooled and then coiled at a temperature in the range of 460-509 DEG C to form an aluminum-clad coil. The steel-aluminum interface of the aluminum-clad coil diffuses iron and aluminum atoms during the heat preservation process, further improving the interface bonding strength; and a high coiling temperature is prone to promote the formation of iron-aluminum compounds between the steel and aluminum, deteriorating the steel-aluminum bonding performance. The aluminum-clad coil is required to be water-cooled immediately after rolling, and the cooling rate is controlled to be greater than or equal to 20 DEG C / s.

[0042] The high-strength double-sided aluminum-clad plate strip prepared by the process of the present application realizes the initial bonding of steel and aluminum through hot dipping, and the required cladding thickness is obtained by limiting the temperature difference between the strip steel and the aluminum liquid; and the steel-aluminum bonding strength is further improved through rolling deformation. During the subsequent coiling and heat preservation process, the matrix structure recovers and recrystallizes, on the one hand, the plasticity of the material is restored to meet the subsequent complex cold working requirements; at the same time, the mutual diffusion of iron and aluminum atoms occurs between the aluminum layer and the steel matrix during the coiling and heat preservation process, and the steel and aluminum realize metallurgical bonding, further improving the steel-aluminum bonding strength. Therefore, the conventional annealing heat treatment after aluminum cladding rolling is not required, the process is shortened, and the cost is reduced.

[0043] The aluminum-clad plate strip prepared by using the substrate composition of the present application has an equiaxed ferrite structure. According to existing research results, the recrystallization temperature of ferrite is 450-650 DEG C. Therefore, the lower limit of the coiling temperature cannot be lower than 450 DEG C, otherwise the matrix structure cannot recover sufficiently, the plasticity is low, and the cold forming performance cannot meet the requirements; and a high coiling temperature is prone to promote the formation of iron-aluminum compounds during long-term heat preservation, deteriorating the steel-aluminum bonding performance. In view of the bonding strength and the steel-aluminum bonding performance, the present application limits the coiling temperature to 460-509 DEG C, and air-cools to room temperature.

[0044] Compared with the existing process, the double-sided aluminum-clad plate strip prepared by the hot-dip aluminum cladding + warm rolling process of the present application omits the subsequent annealing process, has higher production efficiency and lower cost.

[0045] In addition, since warm rolling is adopted, the rolling load is significantly reduced compared with the existing room temperature aluminum cladding rolling, the equipment load is reduced, the energy consumption is reduced, and the cost is reduced.

[0046] The aluminum-clad plate described in Chinese Patent Publication No. CN112877636A has an iron-aluminum and iron-aluminum-silicon alloy layer at the interface between the steel and the aluminum, and the thickness of the alloy layer is 2-5 microns. The existence of the alloy layer deteriorates the steel-aluminum interface bonding performance. The aluminum-clad plate strip prepared by the process of the present application has no iron-aluminum compound layer formed at the steel-aluminum interface, and has better steel-aluminum bonding performance; and since the surface aluminum layer has been deformed by rolling, it is more beautiful.

[0047] Compared with Chinese patent publication No. CN102019727, the present application adopts the process of surface aluminizing and warm rolling, omits the subsequent annealing process, the yield and tensile of the plate strip are in the range of 300-400MPa and 450-550MPa respectively, the surface aluminum layer thickness is 10-80μm, namely, the appearance is good and the corrosion resistance is good, which meets the needs of the fields of heat dissipation, corrosion resistance, household appliance panel, cookware and the like. Therefore, the present application is obviously different from the patent.

[0048] The aluminized base plate steel coil used in the process of the present application can be a cold-rolled coil or a hot-rolled coil. When the hot-rolled coil is used, the heat remaining temperature of the hot coil can be utilized to shorten the annealing holding time before hot aluminizing, thereby reducing the cost. The prepared aluminized plate strip has a width of 700-1800mm, which exceeds the existing aluminized plate strip specifications, and can meet the needs of more application fields.

[0049] The high-strength double-sided aluminized plate strip produced by the process of the present application has a yield strength of 300-400MPa, a tensile strength of 450-550MPa, an elongation of ≥22%, and good steel-aluminum interface bonding performance and stamping and drawing processing performance. It is suitable for the production and processing of various structural parts in the fields of heat dissipation, atmospheric corrosion resistance, cookware, household appliance panel and the like.

[0050] Compared with the prior art, the present application has the following advantages:

[0051] 1) Compared with the existing cold-rolled aluminizing process, the hot aluminizing + warm rolling process of the present application has higher efficiency, the coiling temperature of 460-509℃ directly eliminates the subsequent annealing heat treatment; at the same time, the load of the warm rolling equipment is significantly reduced, the energy consumption is reduced, and the production cost is significantly reduced.

[0052] And the production method is simple and the process is short.

[0053] 2) The double-sided aluminized plate strip produced by the method of the present application has a width of 700-1800mm, and the width range can be further expanded according to the characteristics of the equipment, the single-sided aluminized layer thickness of the plate strip is 10-80μm, and the plate strip has excellent steel-aluminum bonding performance, stamping and drawing processing performance and high surface quality, and is suitable for the production and processing of structural parts in the fields of heat dissipation, corrosion resistance, cookware, household appliance panel and the like.

[0054] 4) Compared with the existing aluminized plate, the aluminized plate strip prepared by the hot aluminizing + warm rolling process of the present application has a more beautiful surface because the surface aluminum layer has been deformed by rolling; at the same time, no iron-aluminum compound is formed at the interface, and the interface bonding performance is better.

[0055] 5) The double-sided aluminum-coated plate strip prepared by the process of the present application has excellent corrosion resistance of aluminum, longer service life, good appearance quality, and can be used without coating, thereby reducing coating cost and lowering comprehensive cost.

[0056] 6) The high-strength double-sided aluminum-coated plate strip substrate of the present application is designed with low C-Mn simple composition, and the surface aluminum layer improves the corrosion resistance. Compared with the existing weather-resistant steel, the addition of valuable alloy elements is reduced, and the aluminum layer on the surface improves the cold forming performance of the plate strip, meeting the 0a and 180° cold bending requirements.

[0057] 7) The substrate used in the present application controls the oxygen content to be 0.004-0.010%, avoiding the problems of nozzle erosion and mold powder degeneration in the casting process induced by high oxygen content of the aluminum-coated substrate, and reducing the production cost.

[0058] 8) The high-strength double-sided aluminum-coated plate strip of the present application has a yield strength of 300-400 MPa, a tensile strength of 450-550 MPa, and an elongation of ≥22%, and excellent plasticity. DETAILED DESCRIPTION

[0059] The present application will be further described below in conjunction with examples.

[0060] The chemical composition of the aluminum-coated plate strip substrate of the present application is shown in Table 1; the production process parameters of the examples are shown in Tables 2 and 3; and the performance of the finished product is shown in Table 4.

[0061] The high-strength double-sided aluminum-coated plate strip obtained according to the steel composition design range and rolling process control technology of the present application has a yield strength of 300-400 MPa, a tensile strength of 450-550 MPa, an elongation of ≥22%, excellent steel-aluminum interface bonding performance, good cold bending processing performance, corrosion resistance, and good appearance quality, and can be used without coating.

[0062] The examples obtained according to the substrate composition design range and aluminum-coated plate strip preparation technology of the present application all meet the requirements of a yield strength of 300-400 MPa, a tensile strength of 450-550 MPa, and an elongation of ≥22%; the width is 700-1800 mm, and the plasticity is good. The high-strength double-sided aluminum-coated plate strip has good steel-aluminum interface bonding strength and surface quality, and meets the cold forming processing requirements of structural parts in the fields of heat dissipation, corrosion resistance, cookware, and household appliance panels.

[0063] The process of the present application can be used to produce different specifications of wide high-strength double-sided aluminum-coated plate strips as needed, which have good appearance and can be used without coating, thereby reducing the painting process and cost. The above specifications, aluminum layer thickness, and substrate thickness are only examples, and in actual applications, different specifications of steel and aluminum layer combinations can be used to prepare more aluminum-coated plate strips that meet the needs.

[0064] Table 1 Base sheet chemistry for aluminized sheet and strip examples (wt%)

[0065] C Si Mn P S Al B O N Example 1 0.0126 0.0074 0.86 0.0173 0.0047 0.0028 0.0017 0.0066 0.0086 Example 2 0.0335 0.0076 0.56 0.0087 0.0048 0.0034 0.0020 0.0084 0.0058 Example 3 0.0022 0.0026 1.28 0.0109 0.0051 0.0016 0.0011 0.0049 0.0032 Example 4 0.0484 0.0097 1.47 0.0104 0.0055 0.0027 0.0016 0.0070 0.0069 Example 5 0.0294 0.0068 1.04 0.0097 0.0068 0.0046 0.0009 0.0086 0.0053 Example 6 0.0366 0.0073 0.61 0.0177 0.0067 0.0032 0.0020 0.0070 0.0095 Example 7 0.0390 0.0054 0.97 0.0176 0.0030 0.0047 0.0014 0.0049 0.0094 Example 8 0.0201 0.0021 1.13 0.0190 0.0065 0.0025 0.0006 0.0054 0.0100

[0066] Table 2 Process parameters for aluminized sheet and strip production

[0067]

[0068]

[0069] Table 3 Process parameters for aluminized sheet and strip production

[0070]

[0071] Table 4 Mechanical properties for aluminized sheet and strip

[0072]

Claims

1. A high-strength double-sided aluminum-clad sheet / strip, comprising a substrate and aluminum cladding layers on its upper and lower surfaces, wherein the chemical composition of the substrate by weight percentage is: C: 0.002–0.05%, Si ≤ 0.01%, Mn: 0.55–1.5%, P ≤ 0.02%, S ≤ 0.008%, Al ≤ 0.005%, N: 0.003–0.010%, O: 0.004–0.0100%, B: 0.0005–0.0020%; the balance including Fe and other unavoidable impurity elements.

2. The high-strength double-sided aluminum-coated sheet and strip as described in claim 1, characterized in that, The substrate composition balance consists of Fe and other unavoidable impurity elements.

3. The production method of high-strength double-sided aluminum-clad sheet and strip as described in claim 1 or 2, characterized in that, The thickness of the aluminum cladding layer on one side of the aluminum-clad sheet / strip is 10 μm or more.

4. The method for producing high-strength double-sided aluminum-clad sheet and strip as described in claim 1, 2, or 3, characterized in that, The thickness of the aluminum cladding layer on one side of the aluminum-clad sheet / strip is 40–80 μm.

5. The method for producing high-strength double-sided aluminum-clad sheet and strip as described in claim 1, 2, 3, or 4, characterized in that, The width of the aluminum-clad sheet strip is 700–1800 mm.

6. The high-strength double-sided aluminum-coated sheet and strip as described in claim 1, 2, 3, 4, or 5, characterized in that, The aluminum-clad sheet has a yield strength of 300-400 MPa, a tensile strength of 450-550 MPa, and an elongation A ≥ 22%.

7. The method for producing high-strength double-sided aluminum-clad sheet and strip as described in any one of claims 1 to 6, characterized in that, Includes the following steps: 1) Annealing, hot-dip galvanizing After pickling, the substrate is annealed and then enters the aluminum plating bath for hot plating. The annealing temperature is 610-630℃ and the annealing time is 60-88s. The aluminum liquid temperature is 610-628℃ and the temperature of the substrate entering the aluminum plating bath is 605-620℃, which is 2-10℃ lower than the aluminum liquid temperature. 2) Warm rolling After hot-dip aluminum plating, the aluminum-clad sheet and strip are directly fed into the rolling mill for rolling to obtain the finished double-sided aluminum-clad sheet and strip of the required thickness; wherein, the deformation of the first pass is ≥45%; the rolling can be single-pass or multi-pass, and the total deformation of multi-pass rolling is required to be ≥60%; 3) Winding The rolled aluminum-clad sheet and strip are immediately water-cooled at a rate of 20°C / s or higher, and then wound into aluminum-clad coils at a temperature of 460–509°C.

8. The method for producing high-strength double-sided aluminum-clad sheet and strip as described in claim 7, characterized in that, Step 1) Annealing is performed using continuous annealing.

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