Metal corundum complex preparation method based on secondary casting molding

Abstract

The invention discloses a preparation method of a metal corundum complex based on secondary casting molding. The preparation method comprises the following steps: determining preset design parameters of an irregular brown corundum block and completing structural design of the complex; a single-layer metal corundum composite plate structure is designed, and a corresponding precision casting mold shell is machined; the method comprises the following steps: pretreating irregular brown fused alumina blocks, and assembling the irregular brown fused alumina blocks in a precision casting mold shell to form a single-layer pre-casting body; preheating the single-layer pre-casting body, casting molten steel, preserving heat, cooling, and demolding to obtain a single-layer metal corundum composite plate; preparing single-layer composite boards in batches, and arranging the single-layer composite boards in a casting sand box according to design parameters to form a composite pre-casting body; molten steel is secondarily smelted and cast into a complex pre-casting body, and the metal corundum complex is obtained after cooling and demolding. The irregular brown corundum blocks and the steel substrate are stably compounded through a secondary casting process, the problems that the irregular corundum blocks are not uniformly distributed and the positions are difficult to control are solved, and the structural uniformity, wear resistance and impact resistance of the compound are improved.

Description

Technical Field

[0001] This invention belongs to the field of metal corundum composite preparation technology, and more specifically, relates to a method for preparing metal corundum composites based on secondary casting. Background Technology

[0002] With the continuous development of materials technology, metal-based ceramic composites have gained widespread attention and application in the fields of wear resistance and impact resistance due to the excellent strength and toughness of metals and the outstanding high hardness of ceramics, becoming one of the core materials in these fields. Brown fused alumina, as a typical ceramic material, possesses significant advantages such as high hardness, low density, strong fracture toughness, and high temperature resistance. It shows good application potential in various scenarios such as grinding and polishing, refractory materials, and wear-resistant toughening, making it an ideal ceramic component for preparing high-performance metal-based ceramic composites.

[0003] Currently, the industry has conducted numerous explorations into the preparation processes of metal-based ceramic composites, and related technologies have provided important references for the development of this field. For example, some methods involve introducing molten metal into porous ceramics preheated to above 600°C to obtain composite green bodies, followed by casting and forging processes to improve the density, strength, and bonding performance between the metal and ceramics; others employ hot isostatic pressing (HIP) to fill and compact ceramic powder, preheat it, inject molten metal, and then prepare composite materials through vacuuming, die casting, and aluminizing; still others modify ceramic particles and then mix them with metal-based materials for injection molding to prepare composite materials; in addition, some methods utilize electrochemical deposition, doping with composite fibers, vacuum infiltration, extrusion casting, and powder injection molding to prepare metal-based ceramic composites.

[0004] However, existing methods for preparing metal-based ceramic composites mainly use regular or specific-shaped ceramic materials such as ceramic powder (particle size of tens to hundreds of mesh), ceramic spheres (diameter of 6-20 mm), and porous ceramics as core components, lacking technologies for preparing composites of irregular, bulk ceramic materials. Metal-corundum composites, as a type of metal-based ceramic composite formed by combining metal with irregular brown corundum blocks, face key technical challenges in their preparation: due to the significant density difference between metal and brown corundum, conventional methods such as free stirring are insufficient to ensure the uniform distribution of irregular brown corundum blocks within the metal matrix as designed, severely limiting the performance stability and industrial production progress of metal-corundum composites.

[0005] Therefore, there is an urgent need to develop a metal-alumina composite material and its preparation method that can achieve uniform distribution of irregular brown fused alumina blocks in a metal matrix according to design and is suitable for industrial production. Summary of the Invention

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method for preparing metal-corundum composites based on secondary casting. By employing irregular brown corundum blocks as the ceramic component and combining them with steel to form the metal-corundum composite, this method overcomes the limitations of existing metal-based ceramic composites that rely on regular or specific-shaped ceramic raw materials such as ceramic powder, ceramic spheres, and porous ceramics, effectively expanding the material system of metal-based ceramic composites. Simultaneously, through the process design of the secondary casting method, by pre-setting the distribution parameters of the corundum blocks, preparing composite plates in layers, and then assembling and casting, the technical challenges of uneven corundum distribution and difficult position control caused by the density difference between the metal and the irregular brown corundum blocks are precisely solved. This significantly improves the structural uniformity, wear resistance, and stability of localized impact resistance of the metal-corundum composite. Furthermore, this preparation method can be directly adapted to existing casting processes and equipment, achieving large-scale, industrialized production without large-scale modifications, greatly improving production efficiency. It also provides a referable technical route for the development of similar irregular, large-block ceramic materials combined with metal composites, possessing significant industrial application value and technical reference significance.

[0007] To achieve the above objectives, one aspect of the present invention provides a method for preparing a metal-corundum composite based on secondary casting, comprising the following steps: S1: Determine the preset design parameters of the irregular brown corundum block and complete the structural design of the metal corundum composite. S2: Design the structure of a single-layer metal corundum composite plate according to the structure of the metal corundum composite, and process the precision casting mold shell according to the structure of the single-layer metal corundum composite plate; the precision casting mold shell includes an upper mold shell and a lower mold shell. S3: The irregular brown fused alumina block is cleaned and dried to remove surface impurities. The treated irregular brown fused alumina block is placed in the lower mold shell of the precision casting mold shell. The upper mold shell is covered with the thickness of a single-layer metal fused alumina composite plate and a secondary casting molten steel flow hole is reserved to form a single-layer metal fused alumina composite plate precast body. S4: Place the precast single-layer corundum composite plate in a furnace and heat it to 580-620℃ and keep it at that temperature; melt steel in an electric furnace, and after the temperature of the molten steel reaches 1590-1610℃, pour the molten steel into the precast single-layer corundum composite plate in the heat-keeping state, and remove the precision casting mold shell after natural cooling for 24 hours, and take out the corundum composite plate; S5: Repeat steps S3-S4 to prepare several single-layer metal corundum composite plates; arrange several single-layer metal corundum composite plates in a casting sand box according to the preset design parameters of the metal corundum composite in step S1 to form a pre-cast metal corundum composite. S6: Melt steel in an electric furnace. After the steel temperature reaches 1590-1610℃, pour the steel into the precast metal corundum composite. After natural cooling, remove the sand mold to complete the secondary casting and obtain the metal corundum composite.

[0008] Furthermore, in step S1, the preset design parameters of the irregular brown fused alumina block include the equivalent particle size of the irregular brown fused alumina block, the left-right spacing and front-back spacing between each brown fused alumina block, and the interlayer distance between the upper and lower layers of brown fused alumina blocks.

[0009] Furthermore, the equivalent particle size of the irregular brown fused alumina block is in the range of 20-30 mm; the left-right and front-back spacing between adjacent fused alumina blocks is 10-20 mm; and the interlayer distance between the upper and lower layers of brown fused alumina blocks is 20-50 mm.

[0010] Furthermore, step S2 specifically includes: Based on the structural design scheme determined in step S1, the structural parameters of the single-layer metal corundum composite plate are obtained by disassembly, and the thickness of its metal part is determined to be 10-15mm. The arrangement position, quantity and steel substrate coverage of the brown corundum blocks in the single layer are also refined. Based on the structure of the single-layer metal corundum composite plate, a precision casting mold shell composed of an upper mold shell and a lower mold shell is designed; the cavity size of the mold shell is consistent with the shape of the single-layer composite plate, and a positioning groove for corundum blocks with an equivalent particle size to the corundum blocks is reserved, and a secondary casting molten steel flow hole is preset in the upper mold shell. High-temperature refractory material with a refractory temperature of not less than 1600℃ is selected as the base material of the mold shell. The mold shell is machined according to the design drawings to ensure that the surface of the mold shell cavity is smooth and the dimensional accuracy error is ≤ ±0.5mm. After the processing is completed, the mold shell is fired at 1200-1400℃ and kept at the temperature for 2-4 hours to remove moisture and impurities inside the mold shell.

[0011] Furthermore, in step S2, the diameter of the flow holes for the secondary casting molten steel is 15-30mm, and the number is set according to the size of the composite plate to ensure uniform filling of molten steel.

[0012] Furthermore, in step S3, after cleaning, the drying temperature is 100-150℃, and the drying time is 2-4 hours.

[0013] Furthermore, in step S4, the preheating rate of the precast body is 5-10℃ / min, the holding time is 1-2h, and the casting rate is 5-10kg / s.

[0014] Furthermore, the electric furnace mentioned in steps S4 and S6 is a medium-frequency induction furnace or an electric arc furnace.

[0015] Furthermore, in step S5, the casting sand box is made of quartz sand or alumina sand, and the inner wall of the casting sand box is coated with a release agent.

[0016] Furthermore, a 5-10mm gap is reserved between the inner wall of the sand box and the precast composite body.

[0017] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: (1) This invention proposes a technical approach of using irregular brown corundum blocks as ceramic components to form metal corundum composites with steel. This approach breaks through the limitations of existing metal-based ceramic composites, which rely mainly on regular or specific shaped ceramic raw materials such as ceramic powder, ceramic spheres, and porous ceramics. This approach effectively expands the material system and application scenarios of metal-based ceramic composites.

[0018] (2) The present invention precisely solves the technical problem of uneven distribution of corundum and difficulty in controlling the position caused by the density difference between metal and irregular brown corundum blocks through the process design of the secondary casting molding method, including the steps of preset corundum block distribution parameters, layered preparation of composite plates and reassembly casting.

[0019] (3) The secondary casting molding preparation method of the present invention can be directly adapted to the existing casting process and equipment. It can realize the large-scale and industrialized production of metal corundum composites without large-scale modification, which greatly improves production efficiency. At the same time, it provides a reference technical route for the development of composite materials of similar irregular and bulk ceramic materials and metals, which has important industrial application value and technical reference significance. Attached Figure Description

[0020] Figure 1 This is a schematic flowchart of the method for preparing a metal-corundum composite based on secondary casting in an embodiment of the present invention. Figure 2 This is a schematic diagram of the odd-numbered layer design of the metal-corundum composite in an embodiment of the present invention; Figure 3 This is a schematic diagram of the even-numbered layer design of the metal-corundum composite in an embodiment of the present invention; Figure 4 This is a schematic diagram of the elevation design of the metal corundum composite in an embodiment of the present invention; Figure 5 This is a schematic diagram of the design of the metal-corundum composite before secondary casting in an embodiment of the present invention; Figure 6 This is a schematic diagram of the design of a single-layer corundum composite plate according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the precision casting mold shell of the single-layer metal corundum composite according to an embodiment of the present invention; Figure 8This is a schematic diagram of the structure of a precast single-layer metal corundum composite plate according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the finished single-layer metal corundum composite plate according to an embodiment of the present invention; Figure 10 A schematic diagram of the metal corundum composite sand box structure prepared for casting in an embodiment of the present invention; Figure 11 This is a schematic diagram of the precast corundum composite body according to an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] like Figure 1 As shown, one aspect of the present invention provides a method for preparing a metal-corundum composite based on secondary casting, comprising the following steps: S1: Determine the preset design parameters of the irregular brown fused alumina blocks and complete the structural design of the metal corundum composite; the preset design parameters of the irregular brown fused alumina blocks include the equivalent particle size of the irregular brown fused alumina blocks, the left and right spacing and front and back spacing between each brown fused alumina block, and the interlayer distance between the upper and lower layers of brown fused alumina blocks. S2: Design the structure of a single-layer metal corundum composite plate according to the structure of the metal corundum composite, and process the precision casting mold shell according to the structure of the single-layer metal corundum composite plate; the precision casting mold shell includes an upper mold shell and a lower mold shell. S3: The irregular brown fused alumina block is cleaned and dried to remove surface impurities. The treated irregular brown fused alumina block is placed in the lower mold shell of the precision casting mold shell. The upper mold shell is covered with the thickness of a single-layer metal fused alumina composite plate and a secondary casting molten steel flow hole is reserved to form a single-layer metal fused alumina composite plate precast body. S4: Place the precast single-layer corundum composite plate in a furnace and heat it to 580-620℃ and keep it at that temperature; melt steel in an electric furnace, and after the temperature of the molten steel reaches 1590-1610℃, pour the molten steel into the precast single-layer corundum composite plate in the heat-keeping state, and remove the precision casting mold shell after natural cooling for 24 hours, and take out the corundum composite plate; S5: Repeat steps S3-S4 to prepare several single-layer metal corundum composite plates; arrange several single-layer metal corundum composite plates in a casting sand box according to the preset design parameters of the metal corundum composite in step S1 to form a pre-cast metal corundum composite. S6: Melt steel in an electric furnace. After the steel temperature reaches 1590-1610℃, pour the steel into the precast metal corundum composite. After natural cooling, remove the sand mold to complete the secondary casting and obtain the metal corundum composite.

[0023] Furthermore, step S1 specifically includes: Determine the core parameters of the irregular brown fused alumina blocks: Based on the wear resistance and impact strength requirements of the target composite, determine the equivalent particle size D of the irregular brown fused alumina blocks, with a range of 20-30mm; combined with the overall size of the composite and the requirement for uniform distribution of fused alumina blocks, set the left-right spacing b and front-back spacing d of adjacent fused alumina blocks, both to 10-20mm; based on the composite thickness and interlayer bonding strength standards, determine the interlayer distance h between the upper and lower layers of brown fused alumina blocks, to 20-50mm. Based on the above parameters, a three-dimensional structural model of the metal-corundum composite was constructed using 3D modeling software. The spatial arrangement of the brown corundum blocks in each layer was clearly defined (odd-numbered layers are staggered with even-numbered layers to ensure uniform stress distribution), and the steel matrix filling area was marked, forming a complete structural design scheme (e.g., ...). Figures 2-5 (as shown) Furthermore, step S2 specifically includes: Design of a single-layer corundum composite panel: Based on the structural design scheme determined in S1, the structural parameters of the single-layer corundum composite panel are obtained by disassembly, clarifying the thickness t of its metal part (matching the interlayer distance h, which is 10-15mm), and refining the arrangement position and quantity of brown corundum blocks within the single layer and the extent of steel substrate encapsulation (e.g., Figure 6 (as shown) Precision casting mold shell structure design: Based on the structure of the single-layer metal corundum composite plate, a precision casting mold shell composed of an upper mold shell and a lower mold shell is designed; the cavity size of the mold shell is consistent with the shape of the single-layer composite plate, and a positioning groove for corundum blocks is reserved (matching the equivalent particle size D of the corundum blocks), and secondary casting molten steel flow holes are preset in the upper mold shell (the hole diameter is 15-30mm, and the number is set according to the size of the composite plate to ensure uniform filling of molten steel); Precision casting mold shell processing: High-temperature refractory materials with a refractory temperature not lower than 1600℃ (such as corundum refractory materials) are selected as the mold shell base material. Machining is performed according to the design drawings to ensure a smooth mold shell cavity surface and dimensional accuracy error ≤ ±0.5mm. After machining, high-temperature firing treatment is carried out (temperature 1200-1400℃, holding for 2-4 hours) to remove internal moisture and impurities, improving the high-temperature stability of the mold shell (e.g., ...). Figure 7 (as shown) Furthermore, the pretreatment of irregular brown corundum blocks in step S3 specifically includes: Cleaning treatment: Rinse the brown fused alumina block with clean water; Drying treatment: Place the cleaned brown fused alumina block into a drying oven, control the temperature at 100-150℃, and keep it at that temperature for 2-4 hours to completely remove surface moisture and avoid porosity defects during casting. Corundum block positioning and mold assembly: Place the dried irregular brown corundum blocks one by one into the positioning groove of the lower mold shell of the precision casting mold shell to ensure that the corundum blocks are placed stably and the position meets the design requirements; after all the corundum blocks required for a single layer have been placed, with the thickness t as the interval, the upper mold shell is precisely covered on the lower mold shell, and the upper and lower mold shells are fixed by positioning pins to ensure that the mold shell is tightly closed without gaps. Precast casting: After the mold shell is assembled, check whether the flow holes of the secondary casting molten steel are unobstructed, and finally form a structurally stable single-layer metal corundum composite plate precast casting (such as...). Figure 8 (as shown) Furthermore, the casting and molding of the single-layer corundum composite plate in step S4 includes: Preheating of the precast body: Place the precast body of the single-layer metal corundum composite plate into the heating furnace and heat it to 580-620℃ (preferably 600℃) at a heating rate of 5-10℃ / min. Hold it at this temperature for 1-2 hours to ensure that the temperature of the precast body is uniform and to prevent the molten steel from solidifying rapidly when it cools down during subsequent casting. Steel smelting: Structural steel is selected as the base material and put into a medium-frequency induction furnace or electric arc furnace for smelting; the smelting temperature is controlled to make the molten steel temperature reach 1590-1610℃ and held for 30-60 minutes to ensure that the molten steel composition is uniform and impurities are fully floated and removed. Casting and heat preservation: After heat preservation, the pre-cast body is taken out from the heating furnace and quickly placed in the casting station. Molten steel is slowly poured into the mold cavity through the molten steel flow hole of the upper mold shell. The casting rate is controlled at 5-10 kg / s to avoid molten steel splashing or eddy currents. Demolding and Part Removal: After the composite plate has cooled to room temperature (25-30℃), remove the mold shell positioning pins, separate the upper and lower mold shells, and remove the single-layer metal corundum composite plate (e.g. Figure 9 (As shown); perform preliminary cleaning of the composite board surface to remove the gating gates and attached mold shell debris; Furthermore, the preparation of the precast corundum composite in step S5 includes: Batch preparation of single-layer composite plates: Repeat steps S3-S4, and prepare several single-layer metal corundum composite plates with consistent specifications according to the number of composite layers designed in step S1 and the required quantity of each layer; after each single-layer metal corundum composite plate is prepared, perform dimensional inspection (length and width dimension error ≤ ±1mm) and appearance inspection (no cracks, pores, missing materials and other defects), and only qualified plates can be used for subsequent assembly. Sand box preparation: Select quartz sand or abrasive sand as the sand box base material. Evenly coat the inner wall of the sand box with a release agent (such as graphite powder release agent) to ensure smooth separation of the composite from the sand box later. Determine the sand box specifications based on the overall dimensions of the composite, leaving a 5-10mm gap between the inner wall of the sand box and the pre-cast composite (e.g., ...). Figure 10 (as shown) Single-layer composite plate assembly: Qualified single-layer corundum composite plates are arranged layer by layer in the casting sand box according to the preset design parameters in step S1; adjacent composite plates are fixed together by positioning brackets to ensure that the interlayer distance h meets the design requirements (20-50mm), and that the molten steel flow holes of all composite plates are in the same vertical channel, forming a pre-cast corundum composite body (e.g., Figure 11 (as shown) Furthermore, the preparation of the metallic corundum composite in step S6 includes: Secondary steel smelting: Using the same structural steel raw materials and medium-frequency induction furnace or electric arc furnace as in step S4, molten steel is smelted and the temperature is controlled at 1590-1610℃, and held for 20-60 minutes to ensure that the fluidity and purity of the molten steel meet the requirements for secondary casting. Secondary casting: Molten steel is slowly poured into the molten steel flow channel of the precast corundum composite body, and the casting rate is controlled at 5-12 kg / s to ensure that the molten steel fully fills the gaps between the composite plates and the steel matrix area; the filling of molten steel is observed in real time during the casting process to avoid defects such as incomplete or insufficient casting. Cooling and demolding: After casting, allow the composite to cool naturally to room temperature (25-30℃) in the sand box to fully bond the steel substrate with the single-layer composite plate; after cooling, remove the casting sand box and remove the molding sand and excess risers adhering to the surface; Finished product cleaning: Clean the surface of the demolded metal-corundum composite, and polish it to remove burrs and flash.

[0024] Example 1 Preparation parameters Irregular brown corundum blocks: equivalent particle size 20mm, left and right spacing 10mm, front and back spacing 10mm, and upper and lower layer spacing 20mm; Single-layer corundum composite plate: metal portion thickness 10mm; Precision casting mold shell: corundum refractory material with a refractory temperature of 1600℃, molten steel flow holes with a diameter of 20mm (3 holes), and fired at 1200℃ and held for 2 hours; Pretreatment of brown fused alumina blocks: rinse with clean water for 10 minutes and dry at 100℃ for 2 hours; Preheating of the pre-cast body: Heat to 580℃ at 5℃ / min and hold for 1 hour; Steel smelting: medium frequency induction furnace, temperature 1590℃; Casting parameters: First casting rate 5 kg / s, holding time 20 min; Second casting rate 6 kg / s, temperature 1590℃; Casting sand box: made of quartz sand, with graphite powder release agent applied to the inner wall, and a 5mm gap between the sand box and the pre-cast body; Quantity of single-layer composite panels prepared: 2 pieces; Preparation process S1: Determine the preset design parameters of the above irregular brown corundum blocks, use 3D modeling software to complete the structural design of the metal corundum composite, and clarify the arrangement of the two single-layer composite plates. S2: Based on the structural design of S1, the structural parameters of the single-layer metal corundum composite plate (metal part thickness 10mm) are obtained by disassembly. A precision casting mold shell composed of an upper mold shell and a lower mold shell is designed, with a positioning groove adapted to the 20mm equivalent particle size and three 20mm diameter steel flow holes reserved. Corundum refractory material with a refractory temperature of 1600℃ is selected to process the mold shell to ensure that the cavity size accuracy error is ≤±0.5mm. After processing, it is fired at 1200℃ and held for 2 hours to remove moisture and impurities. S3: After rinsing the irregular brown corundum block in clean water for 10 minutes, dry it at 100℃ for 2 hours; place the treated corundum block into the positioning groove of the lower mold shell of the precision casting mold shell, cover the upper mold shell with the thickness of a single layer composite plate, and reserve the steel flow hole to form a single layer precast body. S4: Heat the single-layer precast body to 580℃ at a rate of 5℃ / min and hold for 1 hour; use a medium-frequency induction furnace to melt the molten steel. After the molten steel reaches 1590℃, pour it into the precast body in the holding state at a rate of 5kg / s. After natural cooling for 24 hours, remove the precision casting mold shell, take out the metal corundum composite plate, and inspect it for defects and dimensional accuracy. S5: Repeat steps S3-S4 to prepare two qualified single-layer metal corundum composite plates; arrange the two single-layer composite plates in the quartz sand casting box according to the preset parameters of S1, ensuring that the interlayer distance and adjacent spacing meet the requirements, to form a pre-cast metal corundum composite body (the gap between the sand box and the pre-cast body is 5mm). S6: The molten steel is remelted in a medium-frequency induction furnace. After the temperature of the molten steel reaches 1590℃, the molten steel is poured into the pre-cast composite body. After naturally cooling to room temperature, the sand mold is removed to complete the secondary casting and obtain the metal corundum composite body.

[0025] The metallic corundum composite prepared in Example 1 of this invention has a uniform structure and regular distribution of corundum blocks.

[0026] Example 2 Preparation parameters Irregular brown corundum blocks: equivalent particle size 30mm, left and right spacing 15mm, front and back spacing 15mm, and upper and lower layer distance 30mm; Single-layer corundum composite plate: metal portion thickness 12mm; Precision casting mold shell: corundum refractory material with a refractory temperature of 1600℃, molten steel flow holes with a diameter of 20mm (3 holes), and fired at 1200℃ and held for 2 hours; Pretreatment of brown fused alumina blocks: rinse with clean water for 10 minutes and dry at 100℃ for 2 hours; Preheating of the pre-cast body: Heat to 600℃ at 7℃ / min and hold for 1.5h; Steel smelting: electric arc furnace, temperature 1600℃; Casting parameters: First casting rate 7 kg / s, holding time 30 min; Second casting rate 7 kg / s, temperature 1600℃; Casting sand box: made of pearl sand, with graphite powder release agent applied to the inner wall, and an 8mm gap between the sand box and the pre-cast body; Quantity of single-layer composite panels prepared: 3 pieces; Preparation process S1: Determine the preset design parameters of the above-mentioned irregular brown corundum blocks, complete the structural design of the metal corundum composite, use 3D modeling software to clarify the spatial arrangement of the three single-layer composite plates (odd-numbered layers and even-numbered layers are distributed alternately), and mark the steel matrix filling area; S2: Based on the structural design of S1, the structural parameters of the single-layer metal corundum composite plate (metal part thickness 12mm) are obtained by disassembly. The precision casting mold shell (upper layer + lower layer) is designed, and a positioning groove adapted to the 30mm equivalent particle size and three 20mm diameter steel flow holes are reserved. Corundum refractory material with a refractory temperature of 1600℃ is selected to process the mold shell. The cavity size accuracy error is controlled to be ≤±0.5mm. After processing, it is fired at 1200℃ and held for 3h to improve the high temperature resistance stability of the mold shell. S3: After rinsing the irregular brown corundum block in clean water for 10 minutes, dry it at 100℃ for 2 hours; accurately place the treated corundum block into the positioning groove of the lower mold shell, cover the upper mold shell (with the thickness of the single-layer composite plate as the interval), check the smoothness of the molten steel flow hole, and form a single-layer pre-cast body. S4: Heat the single-layer precast body to 600℃ at a rate of 7℃ / min and hold for 1.5h; use an electric arc furnace to melt the steel, and after the steel temperature reaches 1600℃, pour it steadily into the precast body at a rate of 7kg / s, hold for 30min and then cool naturally; after cooling, remove the mold shell, take out the metal corundum composite plate, and inspect it for defects and dimensional accuracy. S5: Repeat steps S3-S4 to prepare 4 qualified single-layer corundum composite plates; arrange the 4 single-layer composite plates in the alumina casting sand box according to the preset parameters of S1 by using positioning brackets, ensuring that the spacing and interlayer distance meet the requirements, to form a pre-cast composite body (8mm gap between the sand box and the pre-cast body). S6: The molten steel is remelted in an electric arc furnace to 1600℃, and then slowly poured into the pre-cast composite body. After naturally cooling to room temperature, the sand mold is removed, the surface burrs and risers are cleaned, and the secondary casting is completed to obtain the metal corundum composite body.

[0027] The metal corundum composite prepared in Example 2 has a tight bond between the corundum block and the steel matrix, and good structural uniformity.

[0028] This invention aims to address the technical problem that existing methods for preparing metal-based ceramic composites rely on regularly shaped ceramic raw materials such as ceramic powder and ceramic spheres, lacking methods for preparing irregular, bulk ceramic composites. By employing a secondary casting process, a stable composite of irregular brown corundum blocks and a steel matrix is ​​achieved, solving the problems of uneven distribution and difficult position control of irregular corundum blocks. This improves the structural uniformity, wear resistance, and impact resistance of the composite, and can be adapted to existing casting equipment for large-scale production. It expands the material system and application scenarios of metal-based ceramic composites, possessing significant industrial application value.

[0029] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a metal-corundum composite based on secondary casting, characterized in that, Includes the following steps: S1: Determine the preset design parameters of the irregular brown corundum block and complete the structural design of the metal corundum composite. S2: Design the structure of a single-layer metal corundum composite plate according to the structure of the metal corundum composite, and process the precision casting mold shell according to the structure of the single-layer metal corundum composite plate; the precision casting mold shell includes an upper mold shell and a lower mold shell. S3: The irregular brown fused alumina block is cleaned and dried to remove surface impurities. The treated irregular brown fused alumina block is placed in the lower mold shell of the precision casting mold shell. The upper mold shell is covered with the thickness of a single-layer metal fused alumina composite plate and a secondary casting molten steel flow hole is reserved to form a single-layer metal fused alumina composite plate precast body. S4: Place the precast single-layer corundum composite plate in a furnace and heat it to 580-620℃ and keep it at that temperature; melt steel in an electric furnace, and after the temperature of the molten steel reaches 1590-1610℃, pour the molten steel into the precast single-layer corundum composite plate in the heat-keeping state, and remove the precision casting mold shell after natural cooling for 24 hours, and take out the corundum composite plate; S5: Repeat steps S3-S4 to prepare several single-layer metal corundum composite plates; arrange several single-layer metal corundum composite plates in a casting sand box according to the preset design parameters of the metal corundum composite in step S1 to form a pre-cast metal corundum composite. S6: Melt steel in an electric furnace. After the steel temperature reaches 1590-1610℃, pour the steel into the precast metal corundum composite. After natural cooling, remove the sand mold to complete the secondary casting and obtain the metal corundum composite.

2. The method for preparing a metal-corundum composite based on secondary casting according to claim 1, characterized in that: In step S1, the preset design parameters of the irregular brown fused alumina block include the equivalent particle size of the irregular brown fused alumina block, the left-right spacing and front-back spacing between each brown fused alumina block, and the interlayer distance between the upper and lower layers of brown fused alumina blocks.

3. The method for preparing a metallic corundum composite based on secondary casting according to claim 2, characterized in that: The equivalent particle size of the irregular brown fused alumina blocks ranges from 20 to 30 mm; the left-right and front-back spacing between adjacent fused alumina blocks is 10 to 20 mm; and the interlayer distance between the upper and lower layers of brown fused alumina blocks is 20 to 50 mm.

4. The method for preparing a metallic corundum composite based on secondary casting according to any one of claims 1-3, characterized in that: Step S2 specifically includes: Based on the structural design scheme determined in step S1, the structural parameters of the single-layer metal corundum composite plate are obtained by disassembly, and the thickness of its metal part is determined to be 10-15mm. The arrangement position, quantity and steel substrate coverage of the brown corundum blocks in the single layer are also refined. Based on the structure of the single-layer metal corundum composite plate, a precision casting mold shell composed of an upper mold shell and a lower mold shell is designed; the cavity size of the mold shell is consistent with the shape of the single-layer composite plate, and a positioning groove for corundum blocks with an equivalent particle size to the corundum blocks is reserved, and a secondary casting molten steel flow hole is preset in the upper mold shell. High-temperature refractory material with a refractory temperature of not less than 1600℃ is selected as the base material of the mold shell. The mold shell is machined according to the design drawings to ensure that the surface of the mold shell cavity is smooth and the dimensional accuracy error is ≤ ±0.5mm. After the processing is completed, the mold shell is fired at 1200-1400℃ and kept at the temperature for 2-4 hours to remove moisture and impurities inside the mold shell.

5. The method for preparing a metallic corundum composite based on secondary casting according to claim 4, characterized in that: In step S2, the diameter of the flow holes for the secondary casting molten steel is 15-30mm, and the number is set according to the size of the composite plate to ensure uniform filling of molten steel.

6. The method for preparing a metallic corundum composite based on secondary casting according to any one of claims 1-3, characterized in that: In step S3, after cleaning, the drying temperature is 100-150℃ and the drying time is 2-4 hours.

7. The method for preparing a metallic corundum composite based on secondary casting according to any one of claims 1-3, characterized in that: In step S4, the preheating rate of the precast body is 5-10℃ / min, the holding time is 1-2h, and the casting rate is 5-10kg / s.

8. The method for preparing a metal-corundum composite based on secondary casting according to any one of claims 1-3, characterized in that, The electric furnace mentioned in steps S4 and S6 is a medium-frequency induction furnace or an electric arc furnace.

9. The method for preparing a metallic corundum composite based on secondary casting according to any one of claims 1-3, characterized in that, In step S5, the casting sand box is made of quartz sand or abrasive sand, and the inner wall of the casting sand box is coated with a release agent.

10. The method for preparing a metal-corundum composite based on secondary casting according to claim 9, characterized in that, A gap of 5-10mm is reserved between the inner wall of the sand box and the precast composite body.

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