A method for warm rolling copper-steel composite plates

Abstract

This invention provides a method for warm rolling composite copper-steel plates, comprising the following steps: Step 1, pre-treating the strip steel; Step 2, spraying a uniform and dense copper metal layer onto the surface of the strip steel using a spraying system under vacuum; Step 3, completing the double-sided spraying of copper powder onto the strip steel; and detecting the porosity of the sprayed copper layer after spraying under vacuum; Step 4, placing the sprayed strip steel billet into a vacuum heat treatment furnace for heating; Step 5, performing warm rolling composite on the heated strip steel billet using a four-roll reversible rolling mill under vacuum; Step 6, achieving mechanical bonding between the copper and steel layers at the interface after warm rolling, followed by annealing to obtain the copper-steel composite plate. This invention solves the problem of heat treatment bulging after rolling composite copper and steel plates, improves the cross-sectional bonding strength between the copper and steel layers, results in a longer lifespan for the copper-steel composite plate structure, and saves a significant amount of precious copper, thus greatly reducing costs.

Description

Technical Field

[0001] This invention relates to the field of metal composite material forming technology, and more particularly to a method for warm rolling composite of copper and steel composite plates. Background Technology

[0002] Thin-gauge copper / steel composite plates not only possess the excellent lubrication and thermal conductivity of copper but also the high strength and low cost of steel, making them widely used in the electronics and copper metallurgy fields. The preparation methods for composite plates often involve explosive bonding or rolling bonding using composite strips or slabs. Explosive bonding involves a short and complex instantaneous reaction, resulting in low interfacial bonding rates and unstable bonding strength; it also has limitations for producing thicker copper-steel composite plates. Furthermore, this method has low productivity and yield, and causes significant environmental pollution. Rolled bonding, whether hot-rolled or cold-rolled, requires significant plastic deformation of the composite plate, leading to substantial residual stress at the interface. Secondly, during the mechanical bonding process of rolling, gases and impurities from the environment cannot be avoided from being incorporated. High-temperature heat treatment and annealing often result in bulging and the formation of interfacial oxides, affecting the interfacial bonding effect.

[0003] To address the aforementioned problems, this invention proposes a warm rolling composite method for copper / steel composite plates. This method utilizes vacuum arc spraying of metallic copper followed by vacuum warm rolling and vacuum high-temperature diffusion annealing. The vacuum environment avoids the oxidation of interfacial impurities and bulging issues after composite formation. This invention effectively achieves short-process, thin-gauge copper / steel composite plate preparation, saving materials and production costs, and provides a new approach for preparing high-quality interfacial bonding metal layered composite materials. Summary of the Invention

[0004] To address the aforementioned technical problems, a warm rolling composite method for copper-steel composite plates is provided.

[0005] The technical means employed in this invention are as follows:

[0006] A method for warm rolling copper-steel composite plates includes the following steps:

[0007] Step 1: Pre-treat the strip steel;

[0008] Step 2: In a vacuum environment, a uniform and dense copper metal layer is sprayed onto the surface of the strip steel using a spraying system.

[0009] Step 3: Complete the double-sided copper powder coating of the steel strip; after coating in a vacuum environment, test the porosity of the coated copper layer;

[0010] Step 4: Place the coated steel strip into a vacuum heat treatment furnace for heating;

[0011] Step 5: The heated strip steel billet is then subjected to warm rolling composite rolling in a vacuum environment using a four-roll reversible rolling mill.

[0012] Step 6: After warm rolling, mechanical bonding of the copper and steel layers is achieved. After warm rolling, annealing is performed to prepare the copper-steel composite plate.

[0013] Furthermore, in step one, the original strip steel has a thickness of 2~5mm, a width of 200~600mm, and an unlimited length. The surface oxide layer of the strip steel is removed by abrasive belt grinding, and the surface roughness of the strip steel after grinding is kept <40μm. The ground surface of the strip steel is then cleaned with alcohol and acetone in sequence.

[0014] Furthermore, in step two, the spraying method is a vacuum arc spraying method.

[0015] Furthermore, in step two, the spraying material is metallic copper wire, which is pure copper or copper-based material with copper as the base. Pure copper can be brass, bronze, or copper, etc.

[0016] Furthermore, in step two, the spraying system adopts automated control, the spraying atomization pressure is 0.1~0.4MPa, the spraying distance is 40~100mm, the spraying equipment is symmetrically distributed on both sides of the strip, and the strip moves at a constant speed during the spraying process to ensure the uniformity of the spraying. The strip moving speed is 5~15mm / s, and the maximum height of the arc nozzle meets the requirement that the width of the sprayed copper powder reaches 600mm.

[0017] Furthermore, in step three, the thickness of a single layer of sprayed copper powder is 10% to 20% of the thickness of the strip steel.

[0018] Furthermore, in step three, the porosity of the copper layer sprayed under vacuum environment is less than 8% after testing.

[0019] Furthermore, in step four, the coated steel strip is heated to 300-500°C in a vacuum heat treatment furnace.

[0020] Furthermore, in step five, during the warm rolling composite process, constant tension control is used at the head and tail of the strip to avoid warping. The tension is less than the yield strength of the strip used. The total pressure vector during the warm rolling process is 20% to 40% of the total thickness after spraying. The single reduction is 5% to 10%, and the final reduction is 10% to 20%. The rolling method is multi-pass reversible rolling.

[0021] Further, the specific steps of step six are as follows: after warm rolling, mechanical bonding of the copper layer and steel layer interface is achieved; after warm rolling, high-temperature annealing is performed again, and metallurgical bonding is achieved through atomic diffusion; the warm-rolled billet is placed in a reducing atmosphere heat treatment furnace for annealing at a temperature of 600~800℃ for 60~180min; after holding at the temperature, it is rapidly cooled to room temperature by argon gas and then removed from the furnace to obtain a copper-steel composite plate with good interfacial bonding.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The copper-steel composite plate warm rolling composite method provided by the present invention utilizes vacuum arc spraying of metallic copper followed by vacuum warm rolling + vacuum high temperature diffusion annealing to avoid the oxidation of interface impurities and bulging problems after composite under vacuum environment.

[0024] 2. The hot rolling composite method for copper / steel composite plates provided by this invention effectively realizes the preparation of thin-gauge copper / steel composite plates in a short process, saving materials and production costs, and providing a solution for preparing metal layered composite materials with high interfacial bonding quality.

[0025] 3. The hot rolling composite method for copper-steel composite plates provided by this invention solves the problem of heat treatment bulging after copper and steel plates are rolled and composited, improves the cross-sectional bonding strength of the copper layer and the steel layer, and the structure manufactured by copper-steel composite plates has a longer service life. Moreover, it saves a large amount of precious copper metal, greatly reduces costs, and has good economic benefits.

[0026] Based on the above reasons, this invention can be widely applied in fields such as metal composite material forming. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a process flow diagram of the present invention.

[0029] Figure 2 This is a surface view of the strip steel after vacuum spraying brass in Embodiment 1 of the present invention.

[0030] Figure 3 This is a surface view of the copper-steel composite plate after vacuum warm rolling in Embodiment 1 of the present invention. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0035] The purpose of this invention is to provide a short-process warm rolling composite method for copper-steel composite plates, and to propose the following parameters: copper powder spraying thickness, original steel layer thickness, rolling deformation, and post-rolling heat treatment method. This mainly solves the problems of low interfacial bonding strength between copper and steel layers and bulging after heat treatment in conventional composite processes.

[0036] like Figure 1 As shown, this invention provides a warm rolling composite method for copper-steel composite plates, which is a process of coating copper powder onto the surface of steel strips and then rolling the composite. It includes the following steps:

[0037] (1) A uniform and dense copper metal layer is sprayed onto the surface of the strip steel using a vacuum arc spraying method. The spraying material is copper wire, which is pure copper such as brass, bronze, or red copper, or copper-based materials with copper as the base.

[0038] (2) The spraying process is carried out in a vacuum environment.

[0039] (3) The spraying system adopts automatic control, the spraying atomization pressure is 0.1~0.4MPa, the spraying distance is 40~100mm, the spraying equipment and the strip are symmetrically distributed on both sides, and the strip moves at a constant speed during the spraying process to ensure the uniformity of the spraying. The moving speed is 5~15mm / s, and the maximum height of the electric arc nozzle must meet the requirement that the width of the sprayed copper powder reaches 600mm.

[0040] (4) The original strip thickness is 2~5mm, the width is 200~600mm, the strip length is unlimited, the surface oxide layer of the strip is removed by sanding, the surface roughness of the strip is kept <40μm, and then the sanded surface of the strip is cleaned with alcohol and acetone in sequence.

[0041] (5) The strip steel is coated with copper powder on both sides, and the thickness of a single layer of coating is 10% to 20% of the thickness of the strip steel.

[0042] (6) The porosity of the copper layer sprayed under vacuum is less than 8% after testing.

[0043] (7) After spraying, the slab is heated to 300~500℃ in a vacuum heat treatment furnace.

[0044] (8) The heated billet is warm rolled in a vacuum environment using a four-roll reversible rolling mill. The head and tail of the strip are controlled by constant tension to avoid warping. The tension is less than the yield strength of the strip used. The total pressure vector during the warm rolling process is 20% to 40% of the total thickness after spraying. The single reduction is 5% to 10%, and the final reduction is 10% to 20%. The rolling method is multi-pass reversible rolling.

[0045] (9) After warm rolling, the mechanical composite of the copper layer and the steel layer interface is achieved. After the warm rolling is completed, the copper layer is annealed again at high temperature and then metallurgically bonded through atomic diffusion. The warm rolled billet is placed in a reducing atmosphere heat treatment furnace for annealing. The annealing temperature is 600~800℃ and the annealing time is 60~180min. After the heat preservation is completed, the copper steel composite plate with good interface bonding is obtained by passing argon gas to cool it to room temperature.

[0046] This invention solves the problem of heat treatment bulging after copper and steel plates are rolled together, improves the cross-sectional bonding strength of the copper and steel layers, and results in a longer lifespan for copper-steel composite plates. It also saves a large amount of precious copper, significantly reducing costs and providing good economic benefits.

[0047] Example 1

[0048] A method for warm rolling copper-steel composite plates, the specific operation steps are as follows:

[0049] Step 1: Grind the surface of Q235 steel strip with a thickness of 2mm and a width of 200mm. After grinding, clean it with alcohol. The average surface roughness of the steel strip after grinding is 40μm.

[0050] Step 2: Place the strip steel in the center of the arc spraying position. After vacuuming, the upper and lower surfaces should be 40mm away from the spray gun. The strip steel moves at 15mm / s. Using a φ2mm H90 brass wire and atomizing pressure of 0.1MPa, the copper layer thickness on one side reaches 0.2mm. Figure 2 The image shown is a view of the surface of the strip after vacuum spraying brass in this embodiment.

[0051] Step 3: After spraying, the slab is heated to 300°C in a vacuum heat treatment furnace.

[0052] Step 4: The heated billet is then warm-rolled in a vacuum environment using a four-roll reversible rolling mill. Constant tension control is applied to the head and tail of the strip to prevent warping. The tension limit is less than the yield strength of Q235. The total pressure vector during the warm rolling process is 20% of the total thickness after coating. Figure 3 The image shown is a surface view of the copper-steel composite plate after vacuum warm rolling in this embodiment.

[0053] In step 5, the thickness after vacuum spraying is 2.4mm, the total pressure vector during the warm rolling process is 20% of the total thickness after spraying, the thickness after rolling is 1.92mm, and the deformation per pass is controlled according to "2.4mm×0.95×0.95×0.95×0.93".

[0054] Step 6: After warm rolling, the billet is placed in a reducing atmosphere heat treatment furnace for annealing. The annealing temperature is 600℃ and the annealing time is 180min. After the heat treatment is completed, argon gas is passed through and the billet is quickly cooled to room temperature before being taken out of the furnace to obtain a copper-steel composite plate with good interfacial bonding.

[0055] Example 2

[0056] A method for warm rolling copper-steel composite plates, the specific operation steps are as follows:

[0057] Step 1: Grind the surface of a Q235 steel strip with a thickness of 5mm and a width of 600mm. After grinding, clean it with alcohol. The average surface roughness of the steel strip after grinding is 40μm.

[0058] Step 2: Place the strip steel in the middle of the arc spraying position, after vacuuming, the upper and lower surfaces are 100mm away from the spray gun position, the strip steel moves at 5mm / s, and the φ2mm H90 brass wire is sprayed with atomization pressure of 0.4MPa to achieve a single-sided copper layer thickness of 1mm.

[0059] Step 3: After spraying, the slab is heated to 400℃ in a vacuum heat treatment furnace.

[0060] Step 4: After heating, the billet is warm rolled in a vacuum environment using a four-roll reversible rolling mill. Constant tension is used at the head and tail of the strip to avoid warping. The tension limit is less than the yield strength of Q235. The total pressure vector during the warm rolling process is 20% of the total thickness after spraying.

[0061] In step 5, the thickness after vacuum spraying is 7mm, the total pressure vector during the warm rolling process is 40% of the total thickness after spraying, the thickness after rolling is 4.2mm, and the deformation per pass is controlled according to "7mm×0.95×0.92×0.92×0.92×0.92×0.88".

[0062] Step 6: After warm rolling, the billet is placed in a reducing atmosphere heat treatment furnace for annealing at a temperature of 800℃ for 60 minutes. After holding at the temperature, it is rapidly cooled to room temperature by argon gas and then removed from the furnace to obtain a copper-steel composite plate with good interfacial bonding.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A warm rolling method for a copper-steel clad plate, characterized by, The method comprises the following steps: Step one, pretreatment of the strip steel; Step two, spraying a uniform and dense copper layer on the surface of the strip steel by a spraying system under vacuum environment; Step three, completing the double-sided spraying of copper powder on the strip steel; detecting the porosity of the sprayed copper layer under vacuum environment; Step four, placing the sprayed strip steel blank into a vacuum heat treatment furnace for heating; Step five, warm rolling the heated strip steel blank under vacuum environment by using a four-high reversible rolling mill; Step six, realizing the mechanical combination of the copper layer and the steel layer interface after warm rolling, and annealing after the end of warm rolling to prepare the copper-steel composite plate; In the step one, the thickness of the original strip steel is 2-5 mm; In the step two, the spraying method is vacuum arc spraying method; In the step two, the spraying system is automatically controlled, the spraying atomization pressure is 0.1-0.4 MPa, the spraying distance is 40-100 mm, the strip steel moves at a constant speed during the spraying process to ensure the uniformity of the spraying, and the moving speed of the strip steel is 5-15 mm / s; In the step four, the sprayed strip steel blank is heated to 300-500 DEG C by the vacuum heat treatment furnace; The specific steps of the step six are as follows: realizing the mechanical combination of the copper layer and the steel layer interface after warm rolling, and realizing the metallurgical combination by atomic diffusion after high-temperature annealing again after the end of warm rolling, placing the warm-rolled blank in a reducing atmosphere heat treatment furnace for annealing treatment, the annealing temperature is 600-800 DEG C, the annealing time is 60-180 min, after the end of heat preservation, argon is passed to cool to room temperature, and the copper-steel composite plate with good interface combination is obtained.

2. The copper-steel clad plate warm compounding method according to claim 1, characterized by, In the step one, the width of the original strip steel is 200-600 mm, the surface of the strip steel is polished by a sand belt to remove the surface oxide layer, the surface roughness of the polished strip steel is kept to be less than 40 μm, and the polished surface of the strip steel is sequentially cleaned by using alcohol and acetone.

3. The copper-steel clad plate warm compounding method according to claim 1, characterized by, In the step two, the spraying raw material is copper wire, the copper wire is pure copper or copper-based material with copper as the matrix, and the pure copper is brass, bronze or red copper.

4. The copper-steel clad plate warm compounding method according to claim 1, characterized by, In the step two, the spraying equipment is symmetrically distributed on both sides of the strip steel, and the maximum height of the arc spraying nozzle satisfies that the sprayed copper powder width reaches 600 mm.

5. The copper-steel clad plate warm compounding method according to claim 1, characterized by, In the step three, the thickness of the single layer of the sprayed copper powder is 10%-20% of the thickness of the strip steel.

6. The copper-steel clad plate warm coextrusion method according to claim 1, characterized by, In the step three, the porosity of the sprayed copper layer under vacuum environment is less than 8% after detection.

7. The copper-steel clad plate warm coextrusion method according to claim 1, characterized by, In the step five, during the warm rolling combination process, the head and tail of the strip steel are controlled by using constant tension to avoid warping, the tension size is less than the yield strength of the used strip steel, the total compression vector during the warm rolling process is 20%-40% of the total thickness after spraying, the single compression amount is 5-10%, the final compression amount is 10-20%, and the rolling mode is multi-pass reversible rolling.

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