High-strength copper-clad plate strip and method for producing the same

Abstract

A high-strength copper-clad laminate strip and its production method are disclosed, comprising a steel strip and a copper strip laminated together. The steel strip has the following composition by weight percentage: C 0.04-0.10%, Si≤0.10%, Mn 0.20-0.80%, Al 0.01-0.04%, P≤0.018%, S≤0.008%, N≤0.005%, and optionally one or more of Ti 0.01-0.06%, Nb 0.01-0.03%, Cr 0.03-0.15%, and Ca 0.001-0.004%, with the balance containing Fe and other unavoidable impurities. This invention eliminates the banded structure in copper-clad laminate strips, obtaining an equiaxed or polygonal ferrite + pearlite structure with a pearlite area ratio of ≤5%. This allows for the adaptation to the severe deformation processing during copper clad laminate rolling, enabling the rolling of copper-clad laminate strips with widths exceeding 1000mm. It also reduces the amount of welding and splicing processing during application, making it suitable for the manufacture of high-strength container panels. Furthermore, the copper-clad laminate strip exhibits excellent surface quality after stamping, solving the problem of ear formation that easily occurs after stamping of existing copper-clad laminate strips.

Description

Technical Field

[0001] This invention belongs to the field of coating materials, specifically relating to a high-strength copper-clad laminate strip and its production method. Background Technology

[0002] As usage requirements increase, single-material components are insufficient to meet the diverse performance demands of practical applications. Composite panels, prepared from multiple metals using various processes, combine the advantages of different metals, thus satisfying the needs of engineering applications. Currently common composite panels include copper-clad laminates, copper-coated laminates, or titanium-steel and stainless steel-steel composites.

[0003] Copper-clad and aluminum-clad sheets and strips are composite strip materials formed by rolling a copper layer onto the surface of steel strip at room temperature. Structurally, they can be either copper-steel or copper-steel-copper. Copper-clad and aluminum-clad sheets and strips combine the strength of steel with the excellent heat dissipation, corrosion resistance, light weight, electrical conductivity, and aesthetics of copper and aluminum, while significantly reducing costs. In particular, copper-clad materials combine the strength of steel with the lubricity and self-sealing properties of copper, and have been widely used in heat sinks, corrosion-resistant pipes, appliance panels, military applications, and electronic components.

[0004] To extend service life, current container steel plates mostly use weathering steel compositions, requiring the addition of numerous corrosion-resistant alloys. Simultaneously, to achieve high strength and weight reduction, reinforcing elements such as Ti and Nb are added, significantly increasing costs. Furthermore, weathering steel is corrosion-resistant overall, but corrosion primarily occurs on the surface, rendering the numerous corrosion-resistant alloys added internally ineffective, thus wasting resources. Copper, as a corrosion-resistant metal, also possesses excellent atmospheric corrosion resistance. Copper-clad laminate combines the strength of steel with the corrosion resistance of copper, making it a viable alternative to current weathering steel in container manufacturing. It is not only more aesthetically pleasing but also offers superior corrosion resistance, reduces surface painting, lowers costs, and is more environmentally friendly, resulting in enormous potential demand.

[0005] Chinese patent CN101660087 discloses "an aluminum-steel-aluminum composite material and its preparation method," which involves surface-treating aluminum and steel, then cold-rolling them into high-precision aluminum strips and steel strips respectively, followed by another cold rolling into a high-precision aluminum-steel-aluminum composite strip, and annealing it at 650–850°C for 1–4 hours. Since the melting point of aluminum is approximately 640°C, annealing at such a high temperature severely deteriorates the interfacial bonding strength between the steel and aluminum.

[0006] Chinese patent CN102019727 discloses "aluminum-coated strip for coolers and its preparation method and the steel strip and aluminum alloy strip used therein", which mainly relates to aluminum-coated steel strips for heat dissipation and the substrates used therein.

[0007] Chinese patent CN107881410A discloses "An aluminum-clad sheet with excellent heat dissipation effect and its production method". The aluminum-clad material involved is mainly used in the production of heat sinks, home appliance panels, etc., and the width of the produced copper-clad sheet does not exceed 500mm.

[0008] Chinese patent CN201645923U discloses "a copper-coated steel strip" and Chinese patent CN201721090U discloses "copper-carbon steel composite plate", which respectively disclose a strip and a plate. The former does not involve a specific method, only stipulating that the Cu content in the copper-coated strip is 5-20%; the latter involves cleaning the surfaces of copper plates and steel plates, stacking them together, heating and rolling them, which is inefficient.

[0009] A comparison with existing patents reveals that current coating materials primarily involve aluminum cladding, with very few technologies and products related to copper cladding. Even when copper-steel sheets are available, their width is limited to no more than 200mm, mainly used for the production of cartridge cases and warheads in the military industry. Their thickness and width are insufficient to meet the requirements for container panels. Furthermore, the strip steel exhibits a distinct banded structure, making its stamping performance unsuitable for processing. Moreover, existing thicker copper-steel composite materials typically employ explosive bonding, a method that yields poor sheet quality, low operational efficiency, and noise pollution. Summary of the Invention

[0010] The purpose of this invention is to provide a high-strength copper-clad laminate strip and its production method, which eliminates the banded structure of the steel strip in the copper-clad laminate strip and obtains an equiaxed or polygonal ferrite + pearlite structure, wherein the pearlite area accounts for ≤5%, which is suitable for the severe deformation processing during copper clad rolling and can roll copper-clad laminate strips with a width exceeding 1000mm. This reduces the amount of welding and splicing processing in the application process and is suitable for the production of high-strength container panels. In addition, the copper-clad laminate strip has good surface quality after stamping, solving the problem of existing copper-clad laminate strip stamping... The copper-clad laminate strip is prone to ear-making problems after pressing; the obtained copper-clad laminate strip has good copper-steel bonding performance, stamping and deep drawing performance and surface quality. In particular, the presence of the copper-clad layer on the surface makes its corrosion resistance much higher than that of weathering steel; its yield strength is ≥300MPa, tensile strength is ≥380MPa, elongation A50 is ≥26%, and it meets the requirements of D=1a and 180° cold bending; at the same time, the copper-clad laminate strip combines the strength of steel with the corrosion resistance, aesthetics, electrical conductivity and heat dissipation of copper. It can also be used in corrosion-resistant pipes, home decoration, electronic components and other fields.

[0011] To achieve the above objectives, the technical solution of the present invention is as follows:

[0012] A high-strength copper-clad laminate strip is formed by laminating steel strip and copper strip. The steel strip has the following chemical composition by weight percentage: C: 0.04-0.10%, Si≤0.10%, Mn: 0.20-0.80%, Al: 0.01-0.04%, P≤0.018%, S≤0.008%, N≤0.005%, and optionally one or more of Ti: 0.01-0.06%, Nb: 0.01-0.03%, Cr: 0.03-0.15%, and Ca: 0.001-0.004%, with the balance including Fe and other unavoidable impurities.

[0013] Furthermore, the chemical composition of the steel strip contains the remainder as Fe and other unavoidable impurities.

[0014] The steel strip of this invention has a yield strength ≥220MPa, a tensile strength ≥300MPa, and an elongation ≥28%.

[0015] The microstructure of the steel strip in the copper-clad laminate of the present invention is equiaxed or polygonal ferrite + pearlite, wherein the area of ​​pearlite accounts for ≤5%.

[0016] The copper-clad laminate strip of the present invention has a yield strength ≥300MPa, a tensile strength ≥380MPa, an elongation A50 ≥26%, and satisfies D=1a and 180° cold bending.

[0017] The copper-clad laminate strip described in this invention is a copper-steel or copper-steel-copper composite strip.

[0018] In the design of the steel strip chemical composition for the high-strength copper-clad laminate strip of this invention:

[0019] Carbon (C) enhances yield strength through solid solution strengthening and phase transformation strengthening. However, excessively high C content is detrimental to the material's subsequent processing properties, such as stamping and deep drawing. Furthermore, higher C content tends to agglomerate at dislocation and other defect sites, negatively impacting surface quality. Additionally, higher C content easily forms banded pearlite structures in the matrix, hindering the forming and processing of copper-clad laminates. Significant banded structures can lead to earing problems after stamping. Based on actual steelmaking processes, this invention controls the C content to 0.04–0.10%.

[0020] Si is a deoxidizing element and a solid solution strengthening element, increasing yield strength. Si can also increase the work hardening rate during cold working, but it reduces the toughness and plasticity of steel to some extent. However, excessively high Si content can promote graphitization of carbon, which is detrimental to toughness, surface quality, and weldability. Therefore, this invention controls Si content to ≤0.10%.

[0021] Mn is also a common strengthening element in steel. It increases yield strength through solid solution strengthening, but reduces elongation. Appropriate amounts of Mn can combine with sulfur in steel to form MnS, reducing the steel's hot brittleness. However, excessive Mn solid solution strengthens the microstructure, inhibits grain growth, and reduces γ-texture (ND∥). <111> The high strength of the steel plate is detrimental to the stamping and forming process and increases the cost, so its content is controlled between 0.20% and 0.80%.

[0022] Higher phosphorus (P) content causes "cold brittleness" in steel, reduces plasticity and impact toughness, and worsens the weldability and cold bending performance of steel. Furthermore, higher P content is detrimental to the bonding between steel and aluminum. Therefore, the P content in steel should be reduced as much as possible, and should be controlled below 0.018%.

[0023] Sulfur (S) is detrimental to the properties of steel, easily causing "hot brittleness," reducing the low-temperature toughness of steel, and worsening the bonding performance at the steel-aluminum interface. The addition of manganese (Mn) can form MnS with S, and increasing the Mn / S ratio can improve hot ductility. It is necessary to control its content at the lowest possible level. Considering that excessively low content increases the difficulty of steelmaking and production costs, the S content should be controlled below 0.008%.

[0024] Al is an important deoxidizing element in steel. Trace amounts of Al form fine AlN precipitates during steelmaking, which refine austenite grains during subsequent cooling, improving the strength and toughness of the steel. Therefore, it is also used as a nitrogen fixative in steel. However, excessive Al content will form coarse alumina particles, increasing the brittleness of ferrite in the steel and reducing its toughness. Therefore, its content must be controlled within a certain range. This invention controls the Al content to be 0.01–0.04%.

[0025] In steel, nitrogen (N) can form nitrides with Al and Ti. These fine precipitates act as grain boundaries, thus refining the austenite grains. However, higher N content in steel readily combines with Al to form AlN, disrupting the continuity of the steel strip matrix. Furthermore, higher N content tends to accumulate at defects, worsening low-temperature impact toughness. Therefore, the N content must be controlled below 0.0050%.

[0026] In addition to the elements mentioned above, this invention also requires the selective addition of one or more of the following: Ti: 0.01–0.06%, Nb: 0.01–0.03%, Cr: 0.03–0.15%, and Ca: 0.001–0.004%, thereby further improving the strength. Wherein:

[0027] Ti has high chemical reactivity and readily forms compounds with C, N, O, S, etc., precipitating during rolling and cooling. These fine precipitates can pin grain boundaries, thus refining austenite grains and preventing grain growth in the weld heat-affected zone, improving the weldability of the steel sheet. Furthermore, the addition of Ti can increase the r-value of the steel strip (r-value: plastic strain ratio, the ratio of strain in the width direction to strain in the thickness direction during tension, characterizing the deep-drawing performance of the material. A higher r-value means a lower likelihood of surface wrinkling during stamping and better surface quality), thereby improving strain uniformity; however, it also reduces plasticity. Excessive Ti content can lead to the growth and agglomeration of titanium nitride particles at high temperatures, impairing the plasticity and toughness of the steel. Therefore, in this invention, the Ti content is controlled between 0.01% and 0.06%.

[0028] Nitrogen (Nb) is a strong nitride-carbide-forming element. During post-rolling cooling, it can combine with carbon and nitrogen in steel to form intermediate phases such as NbC, Nb(CN), and NbN. The resulting fine carbide particles refine the microstructure, producing fine-grain strengthening and precipitation strengthening effects, significantly improving the strength of the steel plate. Furthermore, Nb can inhibit the expansion of austenite interfaces and increase the recrystallization temperature of steel, allowing for rolling in the non-recrystallization zone at higher temperatures. Therefore, adding an appropriate amount of Nb to steel is beneficial for strength improvement, but the Nb content exceeding 0.06% no longer increases strength. Additionally, the addition of Nb can increase the r-value in the 45° direction, improving strain uniformity, but also reducing elongation and deteriorating plasticity. Higher Nb content leads to the formation of coarse carbonitride particles at grain boundaries, worsening impact toughness. Therefore, in this invention, the Nb content is controlled between 0.01% and 0.03%.

[0029] In steel, Cr forms a continuous solid solution with Fe, resulting in solid solution strengthening. It also forms various types of carbides with C, such as M3C, M7C3, and M... 23 C6 and other elements produce a secondary strengthening effect. However, Cr is a precious alloying element, so the Cr content is controlled between 0.03% and 0.15%.

[0030] Adding Ca to steel can alter the shape of sulfides, suppress the hot brittleness of S, and improve toughness. Furthermore, when excessive Ti is present in the steel, it can form titanium sulfide or titanium carbosulfide with sulfides. Too low a Ca content has little effect, while a content exceeding 0.005% results in excessively large Ca(O,S) assemblies, increasing brittleness and potentially becoming crack initiation points, reducing steel purity, and worsening the toughness of the weld heat-affected zone. Therefore, in this invention, the Ca content is controlled between 0.001% and 0.004%.

[0031] This invention relates to steel grades that require good plasticity for copper-steel cladding rolling, achieving high strength while ensuring the bonding strength between copper and steel. Mn has a solid solution strengthening effect, while C, in addition to solid solution strengthening, also has a phase transformation strengthening effect, and further improves strength through carbide precipitation.

[0032] GJB1458B-2015 also mentions steel strips for copper clad laminates. Based on tensile strength, they are divided into three strength grades: 295MPa, 345MPa, and 385MPa, corresponding to tensile strength ranges of 295–390MPa, 345–440MPa, and 385–480MPa (grades: F11, F18, and F18A), respectively. Compared to this invention, the corresponding steel grades have a higher carbon content (0.11–0.22%), resulting in the formation of a large amount of banded pearlite structure in the matrix. This deteriorates the processing performance of the copper-clad laminate steel strip, so the standard also requires controlling the banded structure to not exceed grade 3. Although the carbon content in the 295–390MPa strength grade steel is ≤0.11%, its upper limit requirements for phosphorus (P) and sulfur (S) are relatively high, which is also detrimental to the processing performance of the copper-clad laminate strip. Moreover, the performance mentioned in the standard is tensile strength, with no requirement for yield strength. Furthermore, this tensile strength needs to be obtained by high-temperature heat treatment of the steel strip, which significantly increases the production difficulty and cost.

[0033] The steel strip used for copper-clad laminates described in this invention employs a lower carbon content, reducing the formation of pearlite in the microstructure. Based on this lower carbon content, Mn is added to improve the strength of the steel strip, and trace amounts of one or more elements selected from Ti, Nb, Cr, and Ca are added to refine the grains and inhibit grain growth during annealing. In particular, the selective addition of appropriate amounts of Nb and Ti increases the r-value, improving the plastic strain capacity of the steel strip. By reducing pearlite formation and eliminating banded structures in the steel strip through compositional design, the invention promotes the formation of an equiaxed or polygonal ferrite matrix with no more than 5% pearlite. This improves the uniformity of plane strain in the steel strip, enhancing its stamping performance and making it suitable for the production of copper-clad laminates and improving the surface quality after subsequent stamping processes. It also solves the problem of ear formation that easily occurs after stamping of existing copper-clad laminates. Furthermore, this invention avoids the formation of banded structures in the microstructure, reducing the deformation resistance of the steel strip. Within the load range of existing equipment, copper-clad laminates with widths exceeding 1000 mm can be produced.

[0034] The method for producing high-strength copper-clad laminate strip according to the present invention includes the following steps:

[0035] 1) Cleaning and polishing of the surfaces of copper strip and steel strip composite;

[0036] 2) Rolling

[0037] Copper strip and steel strip are laminated and rolled at room temperature to form copper-clad laminate strip, with a single-pass rolling deformation of 50-85%.

[0038] Alternatively, copper strip or steel strip is heated and rolled in the temperature range of 200 to 700°C to form copper-clad laminate strip; single-pass rolling deformation;

[0039] 3) Annealing

[0040] The process involves coiling and annealing in a bell-type furnace. The annealing temperature is 400–550℃, and the holding time in the bell-type furnace is t = 120 + 3H, where t is in minutes and H is the thickness of the copper-clad steel coil, which is the outer radius of the steel coil minus the inner radius of the steel coil, in cm. After annealing, the coil is water-cooled to below 200℃ and finally cooled in the furnace to below 80℃ before being removed from the furnace.

[0041] or,

[0042] Continuous annealing and winding, wherein the annealing temperature is 400~550℃, and the continuous annealing time t0=(h+1)×1.5±1min, where h is the thickness of the copper clad laminate strip in mm, and h≥1mm;

[0043] 4) Finishing.

[0044] Preferably, in step 1), the surface cleaning includes pickling, degreasing, and drying.

[0045] Preferably, in step 1), the surface cleaning includes sandblasting or shot blasting.

[0046] Preferably, in step 1), the grinding is performed using a sanding belt or a grinding wheel, and the grinding direction is parallel to the rolling direction.

[0047] Preferably, in step 2), the rolling process in step 2) is performed in one or two passes.

[0048] In the production process of the copper-clad laminate strip described in this invention:

[0049] Surface cleaning of copper and steel strips includes necessary pickling, degreasing and drying, or direct sandblasting and shot blasting to remove oil, rust and oxide scale from the surfaces of the copper and steel strips to be laminated.

[0050] Grinding is used to increase the roughness of the surfaces to be laminated and expose fresh base metal, thereby improving the mechanical bonding strength between steel and copper during copper clad laminate rolling. Grinding is preferably performed using abrasive belts or grinding wheels, which creates a rough surface, improving the mechanical interlocking of copper and steel during copper clad laminate rolling and resulting in better copper-steel bonding strength. Furthermore, grinding creates a micro-work-hardened layer on the surfaces to be laminated. This hardened layer is broken up during copper clad laminate rolling, exposing fresh metal substrate and achieving point contact bonding between copper and steel, thus improving the copper-steel bonding strength.

[0051] During room temperature rolling of copper and steel, the deformation per pass should be controlled within the range of 50% to 85%. When equipment capacity is insufficient or to improve rolling efficiency, appropriate heated rolling can be performed, i.e., online heating of the copper and steel strips, with the heating temperature controlled between 200 and 700°C. This reduces the deformation resistance of the steel and increases the copper cladding rolling speed. Excessive heating temperature can easily cause oxidation on the surfaces to be laminated, affecting the copper-steel bonding strength. Therefore, controlling the rolling atmosphere is necessary, thus increasing costs. Copper cladding rolling is performed on a 1700mm wide copper cladding mill, which can meet the production needs of copper-clad sheets and strips with widths of 1000–1500mm. The wider specifications can meet the needs of more application fields.

[0052] Depending on the requirements, steel and copper strips of different specifications are rolled into copper-clad laminate strips of the desired thickness and structure in 1-2 passes, with single-pass rolling deformation ranging from 50% to 85%. Lower deformation requires more rolling passes, necessitating repeated feeding and threading, extending production time, reducing efficiency, and increasing costs. Furthermore, insufficient deformation at the interface can lead to direct delamination of the copper and steel. While excessive deformation in a single pass increases rolling efficiency, it also results in high rolling loads and demanding equipment requirements. Additionally, the strain difference between copper and steel creates shear strain at the interface, worsening the copper-steel bond strength. The choice between 1 or 2 passes depends on equipment capacity and finished product specifications.

[0053] After copper-clad laminate rolling, the sheet and strip need to be annealed. The purpose of annealing is twofold: firstly, to eliminate work hardening caused by room temperature rolling, reduce stress concentration, restore the plasticity of the copper-clad laminate, and facilitate subsequent product forming and processing; secondly, during annealing, the atoms at the copper-steel interface diffuse into each other, transitioning from the mechanical bond during rolling to a metallurgical bond, further improving the interfacial bonding strength.

[0054] Since the melting point of copper is around 1083℃ (fluctuating depending on the content of other alloys in the copper), the corresponding recrystallization temperature is approximately 269℃. Generally, the annealing temperature is controlled to be at least 100-200℃ above the recrystallization temperature. A lower annealing temperature will significantly increase annealing time, reducing production efficiency and increasing production costs. Conversely, an excessively high annealing temperature will increase energy consumption and production costs. To improve efficiency and shorten annealing time, this invention appropriately increases the annealing temperature, controlling it between 400 and 550℃, specifically determined based on the size and specifications of the copper-clad laminate and the performance of the finished product.

[0055] There are generally two annealing methods: conventional bell-type furnace annealing and continuous annealing. The annealing holding time t of the copper-clad laminate strip is determined comprehensively based on the thickness h (mm) of the copper-clad laminate strip, the furnace temperature T (°C), and the annealing method.

[0056] When continuous annealing is used, the annealing time t0 = (h+1)×1.5±1min, where h≥1mm. The advantage of continuous annealing is that it can save energy by utilizing the deformation and heating during the rolling process, and at the same time, the copper-clad strip is under a certain tension, which further improves the strip shape and obtains a wide copper-clad strip with good deformation.

[0057] When using a bell-type furnace for annealing, the annealing time includes three stages: heating, holding, and cooling. The annealing time is closely related to the thickness of the copper-clad laminate strip, and for copper-clad steel coils, it corresponds to the difference between the inner and outer diameters of the coil. Generally, this is a linear relationship, but the specific ratio may vary depending on the actual situation. The holding time t (min) is controlled based on the thickness H of the copper-clad steel coil (i.e., the difference between the inner and outer radii of the coil), requiring that: t = 120 + 3H, where H is in cm. After the holding period of the bell-type furnace annealing is completed, water is sprayed into the inner shell of the furnace to accelerate cooling to below 200℃, and then the coil is slowly cooled to below 80℃ before being removed from the furnace.

[0058] Because the banded structure is eliminated in the steel strip described in this invention, the driving force for grain recovery and recrystallization after copper-clad rolling is reduced, and the annealing time is also shortened. According to the annealing time control calculation described in this invention, based on a maximum outer diameter of 1800 mm and an inner diameter of 600 mm, the maximum required holding time is 480 minutes, or 8 hours. In contrast, the annealing time in existing processes generally requires 14 to 18 hours. This invention significantly shortens the holding time and reduces production costs.

[0059] After annealing, the copper-clad coil needs to be finished. On the one hand, the board shape is improved and the edges are trimmed. On the other hand, the surface quality is further improved by micro-pressure.

[0060] The present invention has the following advantages:

[0061] 1. The copper-clad laminate strip of this invention uses a simple C-Mn composition design for the steel strip, employing a low C content and adding Mn and trace amounts of Ti, Nb, Cr, and Ca elements to reduce pearlite formation and eliminate the banded structure in the copper-clad laminate strip steel strip. This results in an equiaxed or polygonal ferrite matrix with a pearlite area ratio not exceeding 5%, producing a uniform and fine structure that is suitable for the intense deformation processing during copper cladding rolling. It can roll copper-clad laminate strips with widths exceeding 1000mm, reducing the amount of welding and splicing processing during application. It is suitable for the production of container plates with corrosion resistance requirements. At the same time, the copper-clad laminate strip of this invention combines the strength of steel with the corrosion resistance, aesthetics, electrical conductivity, and excellent heat dissipation of copper, and can also be applied in corrosion-resistant pipes, home decoration, electronic components, and other fields.

[0062] 2. The copper-clad laminate strip of this invention reduces pearlite in the steel strip and eliminates the banded structure in the steel strip, promoting the formation of an equiaxed or polygonal ferrite matrix structure with a very small amount of pearlite. This improves the uniformity of plane strain of the steel strip, gives it better plastic strain characteristics, and enhances its stamping performance. It is suitable for the production of copper-clad laminate strips and the improvement of surface quality after stamping, and solves the problem of ear formation that easily occurs after stamping of existing copper-clad laminate strips.

[0063] 3. The copper-clad laminate can also be annealed in a bell-type furnace after rolling. Since the banded structure is eliminated in the copper-clad laminate strip, the driving force for grain recovery and recrystallization after copper-clad rolling is reduced, and the annealing time can be controlled within 8 hours, which is significantly shorter than the traditional bell-type annealing time of 14 to 18 hours.

[0064] 4. After copper clad strip is rolled, it can also be annealed directly using a continuous annealing process. This can save energy by utilizing the deformation and heating during the rolling process. At the same time, the copper clad strip is under a certain tension, which is a tension annealing process, which can further improve the strip shape and obtain a wide copper clad strip with good deformation.

[0065] 5. Using the composition and process of this invention, copper-clad laminate strips with a width exceeding 1000mm are obtained. These strips possess excellent copper-steel bonding performance, stamping and deep drawing processing performance, and high strength. They also exhibit good surface quality, excellent corrosion resistance, and can be used without coating, reducing coating costs. Their yield strength is ≥300MPa, tensile strength is ≥380MPa, elongation A50 is ≥26%, and they meet the requirements of D=1a and 180° cold bending. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the structure of embodiment 1 of the copper-clad laminate strip of the present invention.

[0067] Figure 2 This is a schematic diagram of the structure of embodiment 2 of the copper-clad laminate strip of the present invention.

[0068] Figure 3 This is a micrograph of the steel strip in the copper-clad laminate strip according to an embodiment of the present invention.

[0069] Figure 4 This is a micrograph of the steel strip in the copper-clad laminate strip according to an embodiment of the present invention. Detailed Implementation

[0070] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0071] See Figure 1 , Figure 2 The diagram shown is a structural schematic of embodiments 1 and 2 of the copper-clad laminate strip of the present invention.

[0072] According to the chemical composition requirements of the steel strip in the copper-clad laminate strip of the present invention, steel strip 1 and copper strip 2 of different specifications are selected, and after surface cleaning and polishing, copper-clad laminate strips are obtained by copper-clad rolling and annealing.

[0073] The finished copper-clad laminate strip has a thickness of 0.5–2.0 mm and a surface copper film thickness of 20–90 μm. The specific thickness can be adjusted according to the usage requirements, design life, and application environment of the component.

[0074] The chemical composition of the steel strip in this embodiment is shown in Table 1, with the balance including Fe and other unavoidable impurities; the production process parameters of this embodiment are shown in Table 2, and the performance of the finished product is shown in Table 3.

[0075] Figure 3 and Figure 4 The image shown is a microstructure photograph of the steel strip in the copper-clad laminate strip according to an embodiment of the present invention.

[0076] like Figure 3 As shown, the steel strip in the copper-clad laminate has an equiaxed ferrite structure plus a pearlite structure with an area ratio not exceeding 5%. Figure 4 The copper-clad laminate shows that the steel strip structure consists of polygonal ferrite and pearlite with an area ratio not exceeding 5%, and no banded structure is observed in either structure.

[0077] The copper-clad laminate strip prepared using the components and processes described in this invention has a yield strength ≥300MPa, a tensile strength exceeding 380MPa, and an elongation of over 26%, meeting the requirements for D=1a and 180° cold bending. Its width exceeds 1000mm, reducing welding and splicing workload in the production process, resulting in high production efficiency, high yield, and lower production costs. It also possesses good plasticity, excellent copper-steel interface bonding performance, good stamping and deep drawing processing performance, and corrosion resistance. It has a good appearance quality and can be used without painting. Furthermore, its excellent copper-steel interface bonding strength and surface quality make it suitable for container panel production and meet various cold forming processing requirements such as stamping and deep drawing. In addition, the copper-clad laminate strip combines the strength of steel with the corrosion resistance, aesthetics, electrical conductivity, and heat dissipation of copper, making it applicable to other fields such as corrosion-resistant pipes, home decoration, and electronic components.

[0078]

[0079]

[0080]

Claims

1. A high-strength copper-clad laminate strip, comprising a steel strip and a copper strip, wherein the steel strip has the following chemical composition by weight percentage: C: 0.04~0.10%, Si≤0.10%, Mn: 0.20~0.80%, Al: 0.01~0.04%, P≤0.018%, S≤0.008%, N≤0.005%, and one or more of Ti: 0.01~0.06%, Nb: 0.01~0.03%, Cr: 0.03~0.15%, Ca: 0.001~0.004%, with the balance being Fe and other unavoidable impurities; The microstructure of the steel strip in the copper-clad laminate is equiaxed or polygonal ferrite + pearlite, wherein the area of ​​pearlite accounts for ≤5%, and there is no banded structure.

2. The high-strength copper-clad plate strip according to claim 1, wherein The steel strip has a yield strength ≥220MPa, a tensile strength ≥300MPa, and an elongation ≥28%.

3. The high-strength copper-clad laminate strip as described in claim 1 or 2, characterized in that, The copper-clad laminate strip has a yield strength ≥300MPa, a tensile strength ≥380MPa, an elongation A50 ≥26%, and meets the requirements of D=1a and 180° cold bending.

4. The high-strength copper-clad laminate strip as described in claim 1 or 2, characterized in that, The copper-clad laminate is a copper-steel or copper-steel-copper composite laminate.

5. The high-strength copper-clad laminate strip as described in claim 3, characterized in that, The copper-clad laminate is a copper-steel or copper-steel-copper composite laminate.

6. The method for producing high-strength copper-clad laminate strip as described in any one of claims 1 to 5, characterized in that, Includes the following steps: 1) Cleaning and polishing the surfaces of the copper strip and steel strip, wherein the polishing is performed using a sanding belt or a grinding wheel, and the polishing direction is parallel to the rolling direction; 2) Rolling Copper strip and steel strip are laminated and rolled at room temperature to form copper-clad laminate strip, with a single-pass rolling deformation of 50-85%; Alternatively, copper strip or steel strip can be thermally rolled in the temperature range of 200~700℃ to form copper-clad laminate strip; the deformation per single pass is 50~85%; 3) Annealing The process involves coiling and bell-type furnace annealing, with an annealing temperature of 400~550℃ and an annealing holding time of t=120+3H, where t is in minutes and H is the thickness of the copper-clad laminate in centimeters. After annealing, the laminate is water-cooled to below 200℃ and finally cooled in the furnace to below 80℃ before being removed from the furnace. Alternatively... Continuous annealing and winding, wherein the annealing temperature is 400~550℃, and the continuous annealing time t0=(h+1)×1.5±1min, where h is the thickness of the copper clad laminate strip in mm, and h≥1mm; 4) Finishing.

7. The method for producing high-strength copper-clad laminate strip as described in claim 6, characterized in that, In step 1), the surface cleaning includes pickling, degreasing and drying.

8. The method for producing high-strength copper-clad laminate strip as described in claim 6, characterized in that, In step 1), the surface cleaning includes sandblasting and shot blasting.

9. The method for producing high-strength copper-clad laminate strip as described in claim 6, characterized in that, In step 2), the rolling process is performed in one pass or two passes.

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