Aluminum-based silicon carbide hot rolling edge crack control method

Abstract

The invention discloses an aluminum-based silicon carbide hot rolling edge crack control method, which comprises the following steps: firstly, obtaining an aluminum-based silicon carbide coiled material and a buffer metal sheet meeting the requirements of specific ductility and thermal expansion coefficient, cleaning and activating the surface of the coiled material, welding the buffer metal sheet on at least one side of the edge of the coiled material so that the outer edge of the buffer metal sheet covers the outer edge of the coiled material, and finally, carrying out hot rolling. The ductility of the buffering metal sheet at the hot rolling temperature is larger than or equal to 20%, and the thermal expansion coefficient ranges from 10 * 10 <-6 > / K to 20 * 10 <-6 > / K. According to the invention, the buffer metal sheets combined by welding are used as a plastic transition layer and a stress buffer layer, and plastic deformation occurs preferentially in the hot rolling process, so that the edge crack resistance of the material in the hot rolling process is improved, and the single-pass reduction rate can be improved from the traditional about 25% to more than 40%, thereby improving the rolling efficiency, the yield and the production stability.

Description

Technical Field

[0001] This invention relates to the field of aluminum-based silicon carbide coil manufacturing technology, specifically to a method for controlling edge cracking during hot rolling of aluminum-based silicon carbide. Background Technology

[0002] Aluminum-based silicon carbide (SiCp / Al) composites are advanced materials with aluminum alloys as the matrix and silicon carbide particles as the reinforcing phase. This composite combines the ductility and toughness of metals with the high strength and high modulus of ceramics, exhibiting excellent properties such as high specific strength, high specific stiffness, low coefficient of thermal expansion, and good dimensional stability. These characteristics make it a promising candidate for applications in aerospace structural components, precision electronic packaging, and optical instrument support, where lightweighting, stiffness, and thermal stability are critical.

[0003] To enable its engineering applications, it must be processed into wide-width coils, and hot rolling is the key plastic processing technology for producing such coils. This process uses rolling forces at high temperatures to cause significant plastic deformation of the material, thereby obtaining coils with the required specifications and performance.

[0004] During hot rolling, due to differences in physical properties such as thermal expansion coefficient and elastic modulus between SiC particles and the aluminum matrix, their ability to coordinate deformation is poor. This deformation incompatibility generates internal stress within the coil, especially in the free plane of the edge region, leading to severe stress concentration. This easily induces microcracks at the interface, which can further propagate into penetrating macroscopic edge cracks. The formation of edge cracks not only directly reduces the yield and dimensional accuracy of the coil, and damages the integrity of the material, but also acts as a stress source, impairing the material's fatigue performance and long-term service reliability.

[0005] Therefore, edge cracking has become a prominent technical bottleneck restricting the high-quality and high-efficiency rolling forming of aluminum-based silicon carbide composite materials. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an improved method for the hot rolling process of aluminum-based silicon carbide, so that the edge portion of aluminum-based silicon carbide can reduce the cracks generated during the rolling process.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows.

[0008] A method for controlling edge cracks during hot rolling of aluminum-based silicon carbide includes the following steps: S10. Obtain aluminum-based silicon carbide roll material and buffer metal sheet that is compatible with its edges; S20. Clean and activate the surface of the aluminum-based silicon carbide roll; S30. The buffer metal sheet is welded to at least one side of the edge of the aluminum-based silicon carbide roll, so that the buffer metal sheet is integrally connected with the aluminum-based silicon carbide roll, and the outer edge of the buffer metal sheet covers the outer edge of the aluminum-based silicon carbide roll. S04. Products are made from aluminum-based silicon carbide coils with welded buffer metal sheets by hot rolling process. The buffer metal sheet, when hot-rolled, has an elongation ≥20% as determined by GB / T 228.2; the coefficient of thermal expansion of the buffer metal sheet is within 10×10⁻⁶. -6 / K~20×10 -6 / K; According to GB / T 6396, the shear strength of the aluminum-based silicon carbide coil with the aforementioned buffer metal sheet is 150 MPa to 240 MPa.

[0009] As a preferred technical solution, in step S10, the width of the buffer metal sheet is 3% to 5% of the width of the aluminum-based silicon carbide roll; and / or the width of the buffer metal sheet is ≥3mm.

[0010] As a preferred technical solution, in step S10, the thickness of the buffer metal sheet is 2% to 10% of the thickness of the aluminum-based silicon carbide roll; and / or the thickness of the buffer metal sheet is ≥30μm.

[0011] As a preferred technical solution, step S20 includes: S21. Clean the edge area of ​​the aluminum-based silicon carbide roll with an organic solvent; S22. Chemically clean the mechanically treated surface using an acid pickling solution.

[0012] As a preferred technical solution, in step S03, the buffer metal sheet is welded to both sides of the edge of the aluminum-based silicon carbide roll, and the buffer metal sheets on opposite sides are welded together as one unit.

[0013] As a preferred technical solution, in step S03, the welding includes diffusion welding, which is carried out in an atmosphere protection furnace. The temperature of the atmosphere protection furnace is set at 540℃~590℃, the heating rate is 5℃~20℃ / min, the welding pressure is maintained at 2Mpa~5Mpa, and after the aluminum-based silicon carbide coil and the buffer metal sheet reach the welding temperature, the temperature is maintained for 3min~5min.

[0014] As a preferred technical solution, the buffer metal sheet includes one of pure copper, oxygen-free copper, aluminum bronze, pure nickel, nickel-based high-temperature alloy, nickel-plated copper, titanium, or titanium alloy.

[0015] As a preferred technical solution, the surface of the buffer metal sheet is plated with a nickel layer, the thickness of which is 50nm-5μm.

[0016] As a preferred technical solution, the hot rolling process includes: homogenizing the aluminum-based silicon carbide coil with welded buffer metal sheet edging in a temperature range of 380°C to 480°C, and rolling the aluminum-based silicon carbide coil after reaching the homogenization temperature, with a reduction of 25% to 40% per rolling pass.

[0017] An aluminum-based silicon carbide roll material is prepared by the method shown in any of the above technical features.

[0018] The advantages and beneficial effects of this invention are as follows: By selecting a buffer metal sheet with certain ductility and thermal expansion properties, and using a welding process to bond it to the edge of the aluminum-based silicon carbide coil, the plastic deformation of the buffer metal preferentially absorbs and distributes the local stress at the edge during the rolling process, reducing the stress peak at the edge of the aluminum-based silicon carbide, thereby inhibiting the generation and propagation of microcracks; the thermal expansion coefficient of the buffer metal sheet is between that of silicon carbide and the aluminum matrix, forming a transition layer, effectively alleviating the interfacial thermal stress caused by thermal mismatch and avoiding thermal fatigue damage; the welding process, especially diffusion welding, can promote the formation of solid solutions or intermetallic compounds at the interface, achieving metallurgical bonding and improving the interfacial bonding strength; the buffer metal sheet has a passivation and coating effect on microcracks, hindering crack propagation.

[0019] The control method of the present invention can improve the single-pass reduction rate of aluminum-based silicon carbide coils in the hot rolling process. Compared with the traditional reduction rate of about 25%, the present invention can further increase it to 40% without obvious edge cracking, thereby improving the efficiency and stability of its production and manufacturing. Attached Figure Description

[0020] Figure 1 This is a comparison diagram of edge cracking in aluminum-based silicon carbide hot rolling and edge cracking in direct hot rolling, as shown in this invention. Detailed Implementation

[0021] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0022] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly or implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] This invention provides a method for controlling edge cracking during hot rolling of aluminum-based silicon carbide. (See reference...) Figure 1 This method uses an actively placed buffer metal sheet to cover the edge of the aluminum-based silicon carbide coil in a metallurgical manner before high-temperature rolling, thereby constructing a composite structure that combines stress buffering, thermal expansion transition and crack prevention functions. This can suppress the generation and propagation of edge cracks during rolling and improve rolling forming ability.

[0025] This invention first obtains an aluminum-based silicon carbide roll and a buffer metal sheet that is compatible with its edges. Here, "compatible" mainly refers to the fact that the shape of the buffer metal sheet (usually a long strip) can match the edge shape of the roll, which facilitates subsequent bonding and welding operations.

[0026] Before welding, the surface of the aluminum-based silicon carbide coil needs to be cleaned and activated to remove oxides, adsorbed grease, and other contaminants, exposing a clean, metallically active metal substrate surface. A clean surface improves the interface quality for subsequent welding, providing a foundation for high-strength metallurgical bonding. Untreated surfaces often have a passivation layer, which hinders diffusion between metal atoms, resulting in low bonding strength, porous interfaces, and susceptibility to peeling failure under the high stress of subsequent hot rolling.

[0027] Then, the cleaned and activated buffer metal sheet is welded to at least one side of the edge of the aluminum-based silicon carbide coil, ensuring that the outer edge of the buffer metal sheet completely covers the outer edge of the aluminum-based silicon carbide coil. This coverage ensures that during rolling deformation, the free edges of the aluminum-based silicon carbide material are completely encased by the ductile metal, preventing stress from being directly concentrated and released at the brittle silicon carbide / aluminum matrix interface. Instead, the stress is first absorbed and transferred by the outer buffer metal sheet.

[0028] After the welding edges are completed, the composite structure can be subjected to conventional hot rolling processes. During this process, the aluminum-based silicon carbide coil with welded buffer metal sheets enters the rolling mill as a whole, deforming under high temperature and large reduction to ultimately obtain the desired sheet or coil product. After rolling, the buffer metal sheet portion at the edge can be removed as needed.

[0029] This invention specifies that the elongation of the buffer metal sheet at the hot rolling temperature is ≥20%. Elongation is an indicator of a material's ability to undergo plastic deformation. At hot rolling temperatures (e.g., 400-500°C), this elongation requirement ensures that the buffer metal sheet possesses excellent plasticity.

[0030] According to the principles of plasticity mechanics, when a multi-material composite is subjected to rolling pressure, stress preferentially concentrates in regions with low deformation resistance and high plasticity, causing deformation in those regions. Therefore, during hot rolling, the buffer metal sheet with high elongation will undergo relatively significant plastic flow first. This process actively consumes a large amount of deformation work, absorbing the localized high stress that would originally concentrate at the brittle edges of the aluminum-based silicon carbide, thus reducing the stress peak at that location and inhibiting the formation of microcracks.

[0031] Secondly, this invention limits the coefficient of thermal expansion of the buffer metal sheet to 10 × 10⁻⁶. -6 / K to 20×10 -6 The coefficient of thermal expansion (CTE) of silicon carbide particles is approximately 4 × 10⁻⁶ K. -6 / K, the CTE of the aluminum alloy matrix is ​​approximately 24×10 -6 / K. The CTE difference between the two is significant. In the heating and deformation temperature field of hot rolling, this CTE mismatch will generate huge interfacial thermal stress, which is the main cause of interfacial debonding and crack initiation. The CTE value of the selected buffer metal sheet is in the middle range between silicon carbide and aluminum.

[0032] From the perspective of thermoelastic mechanics, when the three components are welded together to form a tight bond, the buffer metal layer in the middle can play a role in gradient transition during temperature changes. This softens the steep CTE gradient between silicon carbide and the aluminum matrix, thereby reducing the shear stress and tensile stress caused by thermal mismatch, avoiding thermal fatigue damage caused by thermal cycling, and improving the structural integrity of the composite material under non-uniform temperature fields.

[0033] Furthermore, the weld interface formed by this method has a shear strength between 150 MPa and 240 MPa. Too low an interface strength means a weak bond, making it prone to delamination under rolling shear stress, causing the buffer layer to fail. While too high a strength may result in a strong bond, it could mean the formation of excessive hard and brittle intermetallic compounds, thus reducing interface toughness and making it prone to brittle cracking under stress. 150-240 MPa provides sufficient strength to transfer loads and coordinate deformation, while retaining a certain degree of toughness to dissipate energy. This strength is typically achieved through welding processes (such as diffusion welding), forming a microstructure at the interface that is primarily composed of solid solution supplemented with a suitable amount of fine, uniform intermetallic compounds.

[0034] In some embodiments, to precisely control the edge protection range of the buffer metal sheet and optimize material utilization, in step S10, the width of the buffer metal sheet is 3% to 5% of the width of the aluminum-based silicon carbide coil, and its width is not less than 3 mm. Stress analysis shows that the high stress concentration area during hot rolling is mainly distributed within a range of about 1%-3% of the plate width from the edge. Setting the width of the buffer metal sheet to 3%-5% of the plate width can completely cover and moderately extend beyond this high stress area, ensuring sufficient protection. At the same time, the requirement of an absolute width of not less than 3 mm is to prevent difficulties in processing and welding operations caused by the buffer metal sheet being too narrow, as well as possible tearing due to excessive local deformation during rolling. If the width ratio is too low or the absolute width is too small, the protection range is insufficient, and the risk of edge cracking is still high; if the width ratio is too high, although the protection is more sufficient, it will unnecessarily increase the consumption of precious metal buffer material and the workload of subsequent cutting, resulting in reduced economy.

[0035] It should also be noted that, in the art, or as claimed in this invention, the acceptable range for cracking or fissures to occur is a buffer metal sheet width of 5% of the plate width.

[0036] Furthermore, in some embodiments, in step S10, the thickness of the buffer metal sheet is 2% to 10% of the thickness of the aluminum-based silicon carbide coil, and its thickness is not less than 30 μm. On the one hand, the buffer layer needs sufficient thickness to bear and absorb the plastic deformation work. According to elastoplastic mechanics, within a certain range, increasing the thickness of the buffer layer can improve its stress absorption capacity and deformation coordination ability. On the other hand, an excessively thick buffer layer will increase the overall rolling force and may generate new interface problems after rolling due to the large difference in deformation between the buffer layer and the substrate. A ratio of 2%-10% provides an effective and economical thickness range. At the same time, the absolute thickness requirement of not less than 30 μm is provided to take into account the surface roughness, micro-defects, and to ensure that diffusion welding can form a continuous and effective bonding layer during the actual rolling process. When the thickness is less than 10 μm, the buffer layer may be too thin and its plasticity may be exhausted or it may crack in the early stage of rolling; while when the thickness exceeds 15% of the substrate thickness, it may have an adverse effect on the rolling deformation law of the main material and increase the complexity of process control.

[0037] In some embodiments, the cleaning and activation treatment in step S20 specifically includes: first, ultrasonically cleaning the edge area of ​​the aluminum-based silicon carbide coil using organic solvents such as acetone and ethanol, mainly to remove oil stains and some loose particles; then, chemically cleaning the treated surface using an acid pickling solution containing hydrofluoric acid, nitric acid, etc. Acid pickling not only further removes residual organic contaminants and a more stable oxide layer, but also produces a slight etching effect on the aluminum substrate surface, increasing surface roughness and active site density. This physically and chemically treated surface has high surface energy and strong atomic activity, which is very beneficial for interdiffusion with the atoms of the buffer metal sheet during subsequent welding, forming a strong metallurgical bond.

[0038] In some preferred embodiments, to achieve the most thorough coverage and protection of the edges of the aluminum-based silicon carbide coil, in step S30, buffer metal sheets are welded to both sides of the edge of the aluminum-based silicon carbide coil, and the buffer metal sheets on both sides are welded together in the thickness direction of the coil. This double-sided coverage and welding structure is equivalent to creating a closed protective shell with the edge of the composite material, which is brittle but has a tough metal. From the perspective of fracture mechanics, when a crack propagates inside the material, it encounters this tough and continuous metal covering layer, and its propagation force (strain energy release rate) is largely consumed due to the expansion of the plastic zone, the crack tip is blunted, and propagation is effectively prevented. Compared with single-sided coverage, double-sided coverage can more evenly withstand the bidirectional pressure from the rolls, avoiding plate warping or premature failure of the buffer layer due to insufficient support on one side.

[0039] In some embodiments, the welding in step S30 is preferably diffusion welding, which is performed in a vacuum or inert gas protected atmosphere furnace to prevent oxidation. Exemplary diffusion welding parameters are: welding temperature set between 540°C and 590°C, heating rate controlled between 5°C / min and 20°C / min, welding pressure maintained between 2MPa and 5MPa, and holding at the welding temperature for 3 to 5 minutes after reaching the welding temperature. The temperature range of 540-590°C is higher than the recrystallization temperature of aluminum but lower than its melting point, and also lower than the melting point of most buffer metals. At this temperature, the atoms of both aluminum and the buffer metal acquire sufficient diffusion kinetic energy. Appropriate pressure, on the one hand, ensures close physical contact between the contact surfaces, breaking down the surface oxide film and promoting contact of fresh metal atoms; on the other hand, the hydrostatic stress state generated by the pressure helps to suppress the formation of voids.

[0040] Controlling the heating rate ensures uniform heating of the components and reduces thermal stress. The holding time provides the necessary time for atomic diffusion to form a diffusion bonding layer of a certain thickness. If the temperature is too low or the pressure insufficient, the diffusion driving force will be inadequate, resulting in weak interfacial bonding; if the temperature is too high, it may cause excessive grain growth in the aluminum matrix or the formation of too many brittle phases with the buffer metal; if the holding time is too long, it may also lead to an excessively thick brittle phase layer.

[0041] In some embodiments, the material of the buffer metal sheet is selected from pure copper, oxygen-free copper, aluminum bronze, pure nickel, nickel-based superalloys, nickel-plated copper, titanium, or titanium alloys. These materials have good plasticity within the hot-rolling temperature range, moderate coefficients of thermal expansion, and can achieve reliable metallurgical bonding with aluminum alloys through diffusion welding. For example, pure copper and oxygen-free copper have excellent plasticity and are preferred stress-buffering materials; nickel and nickel-based alloys have better high-temperature strength and oxidation resistance. The actual selection can be based on a trade-off between cost, process compatibility, and the performance requirements of the edge material in the final product.

[0042] In a preferred embodiment, to further improve the interfacial bonding quality and process stability, the surface of the buffer metal sheet is plated with a nickel layer, the thickness of which is 50 nm to 5 μm. The nickel plating layer serves as a diffusion barrier layer and a wetting layer. Nickel can form solid solutions with aluminum, copper, etc., but its diffusion rate is relatively controllable. In the initial stage of welding, the thin nickel layer first reacts with aluminum to form a uniform Al-Ni intermetallic compound (such as Al3Ni). This compound can prevent the excessively rapid interdiffusion of aluminum and copper, avoiding the formation of a coarse and brittle Cu-Al phase, and can also provide a good substrate for subsequent copper diffusion, thus improving interfacial wettability. The nickel layer can also effectively prevent the buffer metal (especially copper) from undergoing surface oxidation under the high-temperature environment of welding and hot rolling, maintaining the metal activity.

[0043] From the perspective of heterojunction structure, the interfacial energy, diffusion activation energy, and final phase composition of multilayer structures such as Al / Ni / Cu can be controlled to a certain extent by the coating thickness, providing the possibility of achieving optimal toughness interface design. If the coating is too thin, it may be discontinuous and unable to play an effective role; if it is too thick, it may affect the overall plasticity due to its own hardness, or introduce an excessive amount of Ni-Al brittle phase.

[0044] In some embodiments, in step S40, the hot rolling process parameters include: homogenizing the aluminum-based silicon carbide coil with the welded buffer metal sheet at a temperature of 380°C to 480°C, and then rolling it, with a single-pass reduction of 25% to 40%. The homogenization temperature needs to simultaneously consider the plastic deformation window of the aluminum matrix and avoid the excessive formation of harmful phases, ensuring the aluminum alloy matrix is ​​in its optimal thermoplastic state. Setting the single-pass reduction to 25%-40% reflects the significant performance improvement brought about by this method. In traditional direct hot rolling of aluminum-based silicon carbide, the single-pass reduction is usually limited to 25% due to edge cracking limitations. However, with the edge-wrapping method of this invention, the edges are effectively strengthened and protected, allowing for greater deformation without cracking. A higher single-pass reduction means reducing the total number of rolling passes, shortening the production cycle, improving efficiency, and potentially improving the internal structure of the material due to the deformation heat effect. If the reduction is less than 20%, the technological advantages will not be fully utilized; if it is more than 45%, it may place excessive demands on the mill's capacity or lead to increased uneven deformation in the central area.

[0045] Finally, the present invention also provides an aluminum-based silicon carbide coil, which is prepared by the method described in any of the above-mentioned technical features. Because the edge region of this coil undergoes a buffer metal edge rolling process, its microstructure, residual stress state, and defect density are optimized. Even after the edge material is subsequently removed, its crack resistance and overall quality are superior to products directly rolled using traditional methods, laying the foundation for subsequent precision machining and reliable service.

[0046] The present invention will be specifically described below with reference to the embodiments. In the present invention, the initial thickness of the aluminum-based silicon carbide roll is usually 0.5mm-0.8mm.

[0047] Example 1 A method for controlling edge cracks during hot rolling of aluminum-based silicon carbide includes the following steps: S10. Obtain aluminum-based silicon carbide roll material and buffer metal sheet that is compatible with its edges; The width of the buffer metal sheet is 3% of the width of the aluminum-based silicon carbide roll, which is 3.5mm. The thickness of the buffer metal sheet is 3% of the thickness of the aluminum-based silicon carbide roll, and the thickness is 35μm.

[0048] S20. The edge area of ​​the aluminum-based silicon carbide roll is cleaned and activated: first, ultrasonic cleaning is performed with acetone, and then chemical cleaning is performed with an acid pickling solution containing hydrofluoric acid and nitric acid.

[0049] S30. Weld the buffer metal sheet to one side of the edge of the aluminum-based silicon carbide roll, and make the outer edge of the buffer metal sheet cover the outer edge of the roll. The welding was diffusion welding, carried out in an argon-protected atmosphere furnace, with a welding temperature of 550℃, a heating rate of 8℃ / min, a welding pressure of 3MPa, and a holding time of 4min.

[0050] S40. Hot rolling of aluminum-based silicon carbide coils with welded buffer metal sheets: First, heat treat at 420℃, then roll, with a single pass reduction of 30%.

[0051] The buffer metal sheet is made of pure copper, with an elongation of 25% at hot rolling temperature and a coefficient of thermal expansion of 12×10⁻⁶. -6 / K. The shear strength of the interface after welding is 160MPa.

[0052] The aluminum-based silicon carbide roll obtained in this embodiment has almost no cracks at the edges, with only micron-level microcracks in a very few locations, which does not affect the overall structural integrity.

[0053] Example 2 A method for controlling edge cracks during hot rolling of aluminum-based silicon carbide includes the following steps: S10. Obtain aluminum-based silicon carbide roll material and buffer metal sheet that is compatible with its edges; The width of the buffer metal sheet is 4% of the width of the aluminum-based silicon carbide roll, and the width is 4mm; The thickness of the buffer metal sheet is 8% of the thickness of the aluminum-based silicon carbide roll, and the thickness is 40μm.

[0054] S20. Cleaning and activation treatment of the edge area of ​​aluminum-based silicon carbide roll: First, ultrasonic cleaning is performed with ethanol, and then chemical cleaning is performed with an acid pickling solution containing hydrofluoric acid and nitric acid.

[0055] S30. Weld the buffer metal sheets to both sides of the edge of the aluminum-based silicon carbide roll, and weld the two buffer metal sheets together in the thickness direction of the roll. The welding was diffusion welding, carried out in a vacuum furnace, with a welding temperature of 570℃, a heating rate of 15℃ / min, a welding pressure of 4MPa, and a holding time of 3.5min.

[0056] S40. Hot rolling of aluminum-based silicon carbide coils with welded buffer metal sheets: First, heat treat at 460℃, then roll, with a single pass reduction of 35%.

[0057] The buffer metal sheet is made of oxygen-free copper, with a nickel layer plated on its surface, the nickel layer being 200 nm thick; its elongation at hot rolling temperature is 28%, and its coefficient of thermal expansion is 14 × 10⁻⁶. -6 / K. The shear strength of the interface after welding is 190MPa.

[0058] The aluminum-based silicon carbide roll obtained in this embodiment has almost no cracks at the edges, no obvious visible cracks, and good edge flatness.

[0059] Example 3 A method for controlling edge cracks during hot rolling of aluminum-based silicon carbide includes the following steps: S10. Obtain aluminum-based silicon carbide roll material and buffer metal sheet that is compatible with its edges; The width of the buffer metal sheet is 5% of the width of the aluminum-based silicon carbide roll, and the width is 5mm; The thickness of the buffer metal sheet is 2% of the thickness of the aluminum-based silicon carbide roll, and the thickness is 50μm.

[0060] S20. Clean and activate the edge area of ​​the aluminum-based silicon carbide roll: first clean with acetone, then treat with an acid pickling solution.

[0061] S30. Weld the buffer metal sheets to both sides of the edge of the aluminum-based silicon carbide roll, and weld the two buffer metal sheets together in the thickness direction of the roll. The welding was diffusion welding, carried out in a nitrogen protective atmosphere furnace, with a welding temperature of 540℃, a heating rate of 5℃ / min, a welding pressure of 2MPa, and a holding time of 5min.

[0062] S40. Hot rolling of aluminum-based silicon carbide coils with welded buffer metal sheets: First, heat treat at 380℃, then roll, with a single pass reduction of 25%.

[0063] The buffer metal sheet is made of aluminum bronze, with an elongation of 22% at hot rolling temperature and a coefficient of thermal expansion of 10×10⁻⁶. -6 / K. The shear strength of the interface after welding is 150MPa.

[0064] The aluminum-based silicon carbide roll obtained in this embodiment has almost no cracks at the edges, and the edge structure is intact with no obvious damage.

[0065] Example 4 A method for controlling edge cracks during hot rolling of aluminum-based silicon carbide includes the following steps: S10. Obtain aluminum-based silicon carbide roll material and buffer metal sheet that is compatible with its edges; The width of the buffer metal sheet is 4.5% of the width of the aluminum-based silicon carbide roll, which is 4.2 mm. The thickness of the buffer metal sheet is 10% of the thickness of the aluminum-based silicon carbide roll, and the thickness is 45μm.

[0066] S20. Clean and activate the edge area of ​​the aluminum-based silicon carbide roll: first clean with ethanol, then treat with an acid pickling solution.

[0067] S30. Weld the buffer metal sheets to both sides of the edge of the aluminum-based silicon carbide roll, and weld the two buffer metal sheets together in the thickness direction of the roll. The welding was diffusion welding, carried out in an argon-protected atmosphere furnace, with a welding temperature of 590℃, a heating rate of 20℃ / min, a welding pressure of 5MPa, and a holding time of 3min.

[0068] S40. Hot rolling of aluminum-based silicon carbide coils with welded buffer metal sheets: First, heat treat at 480℃, then roll, with a single pass reduction of 40%.

[0069] The buffer metal sheet is made of nickel-plated copper, with an elongation of 30% at hot rolling temperature and a coefficient of thermal expansion of 20×10⁻⁶. -6 / K. The shear strength of the interface after welding is 240MPa.

[0070] The aluminum-based silicon carbide roll obtained in this embodiment has almost no cracking at the edges, and the edges are smooth after rolling with no crack propagation.

[0071] Example 5 A method for controlling edge cracks during hot rolling of aluminum-based silicon carbide includes the following steps: S10. Obtain aluminum-based silicon carbide roll material and buffer metal sheet that is compatible with its edges; The width of the buffer metal sheet is 3.5% of the width of the aluminum-based silicon carbide roll, which is 3.8 mm. The thickness of the buffer metal sheet is 6% of the thickness of the aluminum-based silicon carbide roll, and the thickness is 38μm.

[0072] S20. Cleaning and activation treatment of the edge area of ​​aluminum-based silicon carbide roll material: First, use acetone for ultrasonic cleaning, and then use acid pickling solution treatment.

[0073] S30. Weld the buffer metal sheet to one side of the edge of the aluminum-based silicon carbide roll, and make the outer edge of the buffer metal sheet cover the outer edge of the roll. The welding was diffusion welding, carried out in a vacuum furnace, with a welding temperature of 560℃, a heating rate of 10℃ / min, a welding pressure of 3.5MPa, and a holding time of 4.5min.

[0074] S40. Hot rolling of aluminum-based silicon carbide coils with welded buffer metal sheets: First, heat treat at 440℃, then roll, with a single pass reduction of 32%.

[0075] The buffer metal sheet is made of pure nickel, with a nickel layer plated on its surface, the thickness of which is 2μm; its elongation at hot rolling temperature is 26%, and its coefficient of thermal expansion is 16×10⁻⁶. -6 / K. The shear strength of the interface after welding is 210MPa.

[0076] The aluminum-based silicon carbide roll obtained in this embodiment has almost no cracks at the edges, no macroscopic cracks at the edges, and only occasional micron-level defects.

[0077] Comparative Example 1 Using the traditional aluminum-based silicon carbide hot rolling process, without the use of buffer metal sheet edge wrapping, the steps are as follows: S1. Directly obtain aluminum-based silicon carbide roll material; S2. Perform routine cleaning on the surface of the roll material; S3. After heat treatment at 400℃, hot rolling is carried out directly, with a single-pass reduction of 25%.

[0078] The aluminum-based silicon carbide roll obtained in Comparative Example 1 showed obvious edge cracks, with crack lengths ranging from 1 to 3 cm, which seriously affected the material integrity and subsequent processing performance.

[0079] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for controlling edge cracking during hot rolling of aluminum-based silicon carbide, characterized in that, Includes the following steps: S10. Obtain aluminum-based silicon carbide roll material and buffer metal sheet that is compatible with its edges; S20. The surface of the aluminum-based silicon carbide roll is cleaned and activated. S30. The buffer metal sheet is welded to at least one side of the edge of the aluminum-based silicon carbide roll, and the outer edge of the buffer metal sheet covers the outer edge of the aluminum-based silicon carbide roll. S40. Hot rolling is performed on the aluminum-based silicon carbide coil with the aforementioned buffer metal sheet welded on. The buffer metal sheet, when hot-rolled, has an elongation of ≥20% as determined by GB / T 228.2, and its coefficient of thermal expansion is within 10×10⁻⁶. -6 / K to 20×10 -6 The shear strength of the aluminum-based silicon carbide roll with the aforementioned buffer metal sheet, as determined by GB / T 6396, is between 150 MPa and 240 MPa.

2. The method for controlling edge cracking in hot rolling of aluminum-based silicon carbide according to claim 1, characterized in that, In step S10, the width of the buffer metal sheet is 3% to 5% of the width of the aluminum-based silicon carbide roll, and / or The width of the buffer metal sheet is not less than 3mm.

3. The method for controlling edge cracking in hot rolling of aluminum-based silicon carbide according to claim 2, characterized in that, In step S10, the thickness of the buffer metal sheet is 2% to 10% of the thickness of the aluminum-based silicon carbide roll, and / or The thickness of the buffer metal sheet is not less than 30 μm.

4. The method for controlling edge cracking in hot rolling of aluminum-based silicon carbide according to claim 1, characterized in that, In step S20, the cleaning and activation process includes: first cleaning the edge area of ​​the aluminum-based silicon carbide roll with an organic solvent, and then chemically cleaning the cleaned surface with an acid pickling solution.

5. The method for controlling edge cracks in hot rolling of aluminum-based silicon carbide according to claim 1, characterized in that, In step S30, the buffer metal sheet is welded to both sides of the edge of the aluminum-based silicon carbide roll, and the buffer metal sheets on both sides are welded together as one unit.

6. The method for controlling edge cracking in hot rolling of aluminum-based silicon carbide according to claim 1 or 5, characterized in that, In step S30, the welding is diffusion welding; the diffusion welding is carried out in an atmosphere-protected furnace, the welding temperature is 540℃ to 590℃, the heating rate is 5℃ / min to 20℃ / min, the welding pressure is 2MPa to 5MPa, and the holding time is 3min to 5min.

7. The method for controlling edge cracks in aluminum-based silicon carbide hot rolling according to claim 1, characterized in that, The material of the buffer metal sheet is selected from one of the following: pure copper, oxygen-free copper, aluminum bronze, pure nickel, nickel-based high-temperature alloy, nickel-plated copper, titanium, or titanium alloy.

8. The method for controlling edge cracking in hot rolling of aluminum-based silicon carbide according to claim 7, characterized in that, The surface of the buffer metal sheet is plated with a nickel layer, the thickness of which is 50 nm to 5 μm.

9. The method for controlling edge cracking in hot rolling of aluminum-based silicon carbide according to claim 1, characterized in that, In step S40, the hot rolling process parameters include: the aluminum-based silicon carbide coil with the welded buffer metal sheet is subjected to homogenization heat treatment at a temperature of 380°C to 480°C and then rolled, with a reduction of 25% to 40% per rolling pass.

10. An aluminum-based silicon carbide roll material, characterized in that, It is prepared by the hot rolling edge crack control method of aluminum-based silicon carbide according to any one of claims 1-5 and 7-9.

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