Gradient composite casting method and gradient composite casting product

Abstract

The invention discloses a gradient composite casting method and a gradient composite casting product, and belongs to the technical field of machine manufacturing. The method comprises the following steps: adhering hard alloy powder to a metal wire mesh, and pressing into a metal mesh with the hard alloy powder; a plurality of metal meshes are fixed to the working part of the casting product mold according to the density gradient; high-temperature liquid of an alloy steel base material subjected to active treatment is adopted for pouring, and a composite casting product with a gradient function is formed, wherein a working part and a base part of the composite casting product are integrally formed. Wherein the active elements of the alloy steel matrix material are Ce and La. By utilizing the migration and adsorption effects of active elements, interface electrochemical and kinetic reactions are initiated, the organization structure and interface energy of a liquid material are changed, the wettability of the material is improved, the binding force between different materials is realized, and a composite casting product with a gradient function is obtained; the wear resistance of the working part of the product, the plasticity and toughness requirements of the matrix part and the service life are ensured, and the actual requirements of mechanical products are met.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical manufacturing, and in particular to a gradient composite casting method and a gradient composite casting product. Background Art

[0002] Many mechanical products in the mechanical field, such as sprockets, shield machine cutters, fine crushing rods, etc., require working parts with high hardness and good wear resistance, and also require matrix parts with good toughness, and form a good connection between the working parts and the matrix parts to avoid the detachment and fracture of the working parts, resulting in the failure of mechanical products. However, the common problems of these mechanical products in the traditional production and preparation processes are: the contradiction between hardness and toughness, the contradiction between high-temperature and low-temperature properties, etc., that is, they cannot meet the requirements of wear resistance of the working parts and toughness of the matrix parts, resulting in easy wear and short life of the products, and cannot meet the actual needs.

[0003] In the prior art (application number: 201410455186.X, patent name: A bimetallic composite cemented carbide particle melting and casting process and its product), a method is adopted in which cemented carbide particles (particle size 0.1mm×0.1mm×0.1mm~20mm×20mm×20mm) are first placed in a mold, and then the matrix material alloy solution is poured to prepare a bimetallic composite product. The obtained product can achieve the metallurgical bonding of the cemented carbide material and the matrix material and has good wear resistance. However, in further practice, it is gradually found that some particles of the cemented carbide part will still fall off in the products using this scheme.

[0004] In the prior art (application number: 202110961975.0, patent name: A composite casting product containing a titanium carbide-based powder metallurgy product), a titanium carbide-based powder metallurgy product containing active elements is melted and formed with a matrix cast steel material to form a dispersed metallurgical fusion between the two. However, in actual use, it still cannot meet the requirements of wear resistance and anti-detachment of mechanical products.

[0005] Therefore, it can be seen that the above-mentioned existing metallurgical and casting processes still have inconveniences and defects and need to be further improved. How to create a new gradient composite casting method and a gradient composite casting product to solve the contradictions that the existing processes cannot solve and overcome the above-mentioned existing technical problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a gradient composite casting method, which changes the surface energy of the matrix material, improves the material wettability, enhances the bonding force between the matrix material and the cemented carbide material, and forms a gradient composite structure by performing active treatment on the alloy steel matrix material, so as to overcome the deficiencies of the existing metallurgical and casting processes.

[0007] To solve the above technical problems, the present invention provides a gradient composite casting method, and the method comprises the following steps:

[0008] (1) Using a metal wire mesh to adhesively bond cemented carbide powder, pressing it into a metal mesh sheet with cemented carbide powder, and drying it;

[0009] (2) Fixing a plurality of metal mesh sheets with cemented carbide powder obtained in step (1) at the working part of the casting product mold;

[0010] (3) Pouring a high-temperature liquid of an alloy steel matrix material subjected to activation treatment into the casting product mold obtained in step (2), the pouring temperature being 1580 - 1650 degrees. During the pouring process, a chemical reaction occurs between the alloy steel matrix material and the cemented carbide powder. After solidification, a composite casting product with an integrally formed working part and matrix part is formed; wherein, the alloy steel matrix material is subjected to activation treatment by adding active elements Ce and La.

[0011] Further improvement: In step (2), a plurality of metal mesh sheets with cemented carbide powder are fixed at the working part of the casting product mold in a form of density gradient arrangement, and the arrangement density of the metal mesh sheets closer to the matrix part in the working part is smaller, and the arrangement density of the metal mesh sheets farther from the matrix part is larger.

[0012] Further improvement: In step (1), the cemented carbide powder uses cemented carbide particles with a particle size of 3 - 15 μm.

[0013] Further improvement: The cemented carbide particles use titanium carbide, tungsten carbide or titanium tungsten carbide, and the metal wire mesh uses a 5 - 15 mesh metal wire mesh, such as a wire mesh, etc.

[0014] Further improvement: In step (3), the alloy steel matrix material comprises the following components by weight percentage: C 0.47 - 0.53%, Mn 0.65 - 1.1%, Si 0.15 - 0.35%, Cr 0.75 - 1.2%, Cu 0.35%, Ni 0.25%, Ce 0.3%, La 0.5%, and the balance is Fe.

[0015] Further improvement: The hardness of the working part of the casting product obtained by the method is HRC50 - 65.

[0016] Further improvement: The impact toughness akv of the support part of the casting product obtained by the method is 35 - 45 J / cm -2 , and the hardness is HRC35 - 45.

[0017] As another improvement of the present invention, the present invention also provides a gradient composite casting product, which is a sprocket. The tooth ring and the tooth body of the sprocket are integrally cast by the above-mentioned gradient composite casting method. The tooth body is the working part, the tooth ring is the matrix part, and the connecting part between the tooth body and the tooth ring has a gradient composite structure.

[0018] As another improvement of the present invention, the present invention also provides a gradient composite casting product, which is a cutter head of a shield machine. The cutter body part and the cutting edge part of the cutter head of the shield machine are integrally cast by the above-mentioned gradient composite casting method. The cutting edge part is the working part, the cutter body part is the matrix part, and the connecting part between the cutting edge part and the cutter body part has a gradient composite structure.

[0019] As another improvement of the present invention, the present invention also provides a gradient composite casting product, which is a fine crushing rod. The end and the front end of the fine crushing rod are integrally cast by the above-mentioned gradient composite casting method. The front end is the working part, the end is the matrix part, and the connecting part between the front end and the end has a gradient composite structure.

[0020] After adopting such a design, the present invention has at least the following advantages:

[0021] The gradient composite casting method of the present invention adjusts the fixing method of the cemented carbide powder in the working part and the material composition of the matrix part. By performing an activation treatment on the alloy steel matrix material by adding active elements Ce and La, and using the migration and adsorption effect of the active elements to trigger interfacial electrochemical and kinetic reactions, the microstructure and interfacial energy of the liquid material are changed, the wettability of the material is improved, and the bonding force between different materials is realized; especially, the density gradient distribution of the cemented carbide powder is realized through a metal wire mesh, and a composite casting product with gradient functions is truly achieved, which can significantly improve the mechanical properties and durability of the entire product.

[0022] The gradient composite casting products prepared by the gradient composite casting method of the present invention, such as sprockets, cutter heads of shield machines, and fine crushing rods, greatly improve the wear resistance of the working parts of the products, the plasticity and toughness requirements of the matrix parts, and the service life, meeting the actual needs of mechanical products. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, the following further detailed description of the present invention will be given in combination with the drawings and specific embodiments.

[0024] Figure 1 is the overall structural schematic diagram of the fine crushing rod of the gradient composite casting product of the present invention.

[0025] Figure 2 is the partial metallographic structure diagram of the working part of the fine crushing rod prepared in Example 1 of the present invention.

[0026] Figure 3 It is a local metallographic structure comparison diagram of the matrix part formed by subjecting the alloy steel matrix material to activation treatment and without activation treatment in the present invention.

[0027] Figure 4 It is a comparison diagram of the grain size of alloy steel in the matrix part formed by subjecting the alloy steel matrix material to activation treatment and without activation treatment in the present invention.

[0028] Figure 5 It is a front view structural sectional view of the shield cutter head prepared in Example 2 of the present invention.

[0029] Figure 6 It is a side view structural sectional view of the shield cutter head prepared in Example 2 of the present invention.

[0030] Figure 7 It is a front view structural sectional view of the sprocket prepared in Example 3 of the present invention. Detailed implementation manners

[0031] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention can be more thoroughly understood and the scope of the present invention can be fully conveyed to those skilled in the art.

[0032] Example 1 Preparation of gradient composite casting product - fine crushing rod

[0033] (1) Use a metal wire mesh with a pore size of 10 meshes to adhesively bond tungsten carbide powder of 3 - 15 μm, press it into a metal mesh sheet, and dry it for standby.

[0034] Among them, the tungsten carbide powder used in this embodiment is high - hardness tungsten carbide powder.

[0035] (2) Fix a number of metal mesh sheets with tungsten carbide powder obtained in step (1) at the front end of the fine crushing rod mold, that is, the working part of the fine crushing rod, in the form of a density gradient arrangement; and the closer to the front end of the working part, the greater the arrangement density of the metal mesh sheets, and the closer to the end of the working part, the smaller the arrangement density of the metal mesh sheets.

[0036] (3) Pour the high - temperature liquid of the alloy steel matrix material subjected to activation treatment into the fine crushing rod mold obtained in step (2), the pouring temperature is 1580 - 1650 degrees, and a chemical reaction occurs between the alloy steel matrix material and the tungsten carbide powder during the pouring process. After solidification, a composite casting product fine crushing rod with an integral molding of the working part and the matrix part is formed, and a gradient composite structure exists at the connection between the working part and the matrix part.

[0037] Among them, the alloy steel matrix material is subjected to activation treatment by adding active elements Ce and La. Specifically, the alloy steel matrix material includes the following components by weight percentage: C 0.5%, Mn 0.9%, Si 0.25%, Cr 1.0%, Cu 0.35%, Ni 0.25%, Ce 0.3%, La 0.5%, and the balance is Fe.

[0038] That is, in this embodiment, the above-mentioned activated alloy steel is used as the matrix material to initiate an interfacial reaction with tungsten carbide in the cemented carbide material, change the surface energy of the liquid material, cause microscopic changes such as adsorption electrochemistry, improve the wettability of the material, refine and homogenize the structure, improve the bonding force between materials, and achieve a fine-crushed rod of a composite casting product with gradient function.

[0039] Attached Figure 1 shows a schematic diagram of the overall structure of the prepared fine-crushed rod. Table 1 below shows the Rockwell hardness values of each part of the fine-crushed rod.

[0040]

[0041] As can be seen from Table 1, the hardness of the fine-crushed rod shows a gradually decreasing distribution trend from the front end of the working part to the end of the matrix part. For example, the hardness at the very front end can reach HRC65-66.

[0042] Attached Figure 2 shows a partial metallographic structure diagram of the working part of the prepared fine-crushed rod, where the dot-like substances are tungsten carbide particles distributed dispersedly. It shows that the working part of the product obtained by this gradient composite casting method has the characteristics of refinement and homogenization.

[0043] In this embodiment, a synchronous experiment was also carried out on the alloy steel matrix material without adding active elements Ce and La (including the following components by weight percentage: C 0.5%, Mn 0.9%, Si 0.25%, Cr 1.0%, Cu 0.35%, Ni 0.25%, and the balance is Fe). The partial metallographic structure of the matrix part of the obtained fine-crushed rod and the grain size of the alloy steel were compared. As attached Figure 3 shows a comparative diagram of the partial metallographic structure of the matrix part formed by subjecting the alloy steel matrix material to activation treatment and without activation treatment. Attached Figure 4 shows a comparative diagram of the grain size of the alloy steel in the matrix part formed by subjecting the alloy steel matrix material to activation treatment and without activation treatment. Table 2 shows the mechanical property parameter values of the matrix part formed by subjecting the alloy steel matrix material to activation treatment and without activation treatment.

[0044] Table 2 Mechanical property parameter values of the matrix part formed by subjecting the alloy steel matrix material to activation treatment and without activation treatment

[0045]

[0046] From the attached Figure 3 、 4 and Table 2, it can be seen that the grain size of the as-cast and solution-treated metallographic structures of the product matrix after activation treatment has been improved by two levels, and other mechanical properties have also been improved to varying degrees.

[0047] Example 2 Preparation of Gradient Composite Casting Product - Shield Machine Cutter

[0048] (1) Use a metal mesh with a pore size of 15 meshes to adhesively bond tungsten carbide powder of 3 - 15 μm, press it into a metal mesh sheet, and dry it for later use.

[0049] Among them, the tungsten carbide powder in this example uses high-hardness titanium carbide powder.

[0050] (2) Fix several metal mesh sheets with titanium carbide powder obtained in step (1) at the front end of the shield machine cutter mold in the form of a density gradient arrangement, that is, the cutting edge part 100 of the working part of the shield machine cutter; and the closer to the cutting edge, the greater the arrangement density of the metal mesh sheets, and the closer to the cutter body part, the smaller the arrangement density of the metal mesh sheets.

[0051] (3) Pour the high-temperature liquid of the alloy steel matrix material after activation treatment into the shield machine cutter mold obtained in step (2), the pouring temperature is 1580 - 1650 degrees, and during the pouring process, a chemical reaction occurs between the alloy steel matrix material and the titanium carbide powder of the tungsten carbide, and after solidification, a gradient functional composite casting product, the shield machine cutter, is formed.

[0052] Among them, the alloy steel matrix material is activated by adding active elements Ce and La. Specifically, the alloy steel matrix material includes the following components by weight percentage: C 0.47%, Mn 0.65%, Si 0.15%, Cr 0.75%, Cu 0.35%, Ni 0.25%, Ce 0.3%, La 0.5%, and the balance is Fe.

[0053] That is, the same as the above example, using an alloy steel matrix material containing active elements Ce and La can initiate an interfacial reaction with the titanium carbide tungsten carbide, change the surface energy of the liquid material, cause microscopic changes such as adsorption electrochemistry, improve the wettability of the material, refine and homogenize the structure, improve the bonding force between materials, and achieve a gradient functional composite casting product, the shield machine cutter.

[0054] Attached Figure 5 and 6The front view and side view structural cross-sectional views of the prepared shield cutter are respectively shown. Moreover, the hardness of the shield cutter gradually decreases from the cutting edge part 100 to the cutter body part 200. The hardness at the forefront of the cutting edge part 100 can reach HRC50 - 65, and the impact toughness akv of the cutter body part 200 is 35 - 45 J / cm -2 , and the hardness is HRC35 - 45.

[0055] Example 3 Preparation of gradient composite casting product - sprocket

[0056] (1) Use a metal mesh with a pore size of 5 meshes to adhesively bond tungsten carbide powder of 3 - 15 μm, press it into a metal mesh sheet, and dry it for standby.

[0057] Among them, the tungsten carbide powder in this example uses high - hardness tungsten carbide powder.

[0058] (2) Fix several metal mesh sheets with tungsten carbide powder obtained in step (1) at the front end of the sprocket die in the form of a density gradient arrangement, that is, the tooth body part 300 of the sprocket working part; and the closer to the tooth edge, the greater the arrangement density of the metal mesh sheets, and the closer to the tooth root, the smaller the arrangement density of the metal mesh sheets.

[0059] (3) Pour the sprocket die obtained in step (2) with a high - temperature liquid of an alloy steel matrix material that has undergone activation treatment. The pouring temperature is 1580 - 1650 degrees. During the pouring process, a chemical reaction occurs between the alloy steel matrix material and tungsten carbide powder of tungsten carbide. After solidification, a sprocket of a gradient - functional composite casting product is formed.

[0060] Among them, the alloy steel matrix material realizes activation treatment by adding active elements Ce and La. Specifically, the alloy steel matrix material includes the following components by weight percentage: C 0.53%, Mn 1.1%, Si 0.35%, Cr 1.2%, Cu 0.35%, Ni 0.25%, Ce 0.3%, La 0.5%, and the balance is Fe.

[0061] That is, the same as Example 1 above, using an alloy steel matrix material containing active elements Ce and La can trigger an interfacial reaction with tungsten carbide hard alloy, change the surface energy of the liquid material, cause microscopic changes such as adsorption electrochemistry, improve the wettability of the material, refine and homogenize the structure, improve the bonding force between materials, and achieve a sprocket of a gradient - functional composite casting product.

[0062] Appendix Figure 7The front view structural sectional views of the prepared sprocket wheels are respectively shown. Moreover, the hardness of the sprocket wheel gradually decreases from the tooth body part 300 to the tooth ring part 400, and the hardness at the forefront of the tooth body part 300 can reach HRC50 - 65, and the impact toughness akv of the tooth ring part 400 is 35 - 45 J / cm -2 , and the hardness is HRC35 - 45.

[0063] As mentioned above, it is only a preferred embodiment of the present invention, and there is no any formal limitation to the present invention. Any simple modification, equivalent change or modification made by those skilled in the art using the disclosed technical content above all fall within the protection scope of the present invention.

Claims

1. A gradient composite casting method, characterized in that, The method includes the following steps: (1) Use a wire mesh to adhesively bond cemented carbide powder, press it into a wire mesh sheet with cemented carbide powder, and dry it; (2) Fix a number of wire mesh sheets with cemented carbide powder obtained in step (1) on the working part of the casting product mold; (3) Pour the casting product mold obtained in step (2) with a high-temperature liquid of an alloy steel matrix material that has been subjected to activation treatment. The pouring temperature is 1580 - 1650 degrees. During the pouring process, a chemical reaction occurs between the alloy steel matrix material and the cemented carbide powder. After solidification, a composite casting product with an integrally formed working part and matrix part is formed. Among them, the alloy steel matrix material is subjected to activation treatment by adding active elements Ce and La.

2. The gradient composite casting method according to claim 1, wherein In step (2), a number of wire mesh sheets with cemented carbide powder are fixed on the working part of the casting product mold in the form of a density gradient arrangement, and the arrangement density of the wire mesh sheets closer to the matrix part in the working part is smaller, and the arrangement density of the wire mesh sheets farther from the matrix part is larger.

3. The gradient composite casting method according to claim 2, wherein In step (1), the cemented carbide powder uses cemented carbide particles with a particle size of 3 - 15 μm.

4. The gradient composite casting method according to claim 3, wherein The cemented carbide particles use titanium carbide, tungsten carbide or titanium tungsten carbide, and the wire mesh uses a wire mesh with 5 - 15 meshes.

5. The gradient composite casting method according to claim 1, characterized in that, In step (3), the alloy steel matrix material includes the following components by weight percentage: C 0.47 - 0.53%, Mn 0.65 - 1.1%, Si 0.15 - 0.35%, Cr 0.75 - 1.2%, Cu 0.35%, Ni 0.25%, Ce 0.3%, La 0.5%, and the balance is Fe.

6. The gradient composite casting method according to claim 1, wherein The hardness of the working part of the casting product obtained by the method is HRC50 - 65.

7. The gradient composite casting method according to claim 6, characterized in that, The impact toughness akv of the support part of the casting product obtained by the said method is 35 - 45 J / cm -2 , and the hardness is HRC35 - 45.

8. A gradient composite casting product, characterized in that, The product is a sprocket. The tooth ring and the tooth body of the sprocket are integrally cast by the gradient composite casting method described in any one of claims 1 to 7. The tooth body is the working part, the tooth ring is the matrix part, and the connection part between the tooth body and the tooth ring has a gradient composite structure.

9. A gradient composite casting product, characterized in that, The product is a shield machine cutter head. The cutter body part and the cutting edge part of the shield machine cutter head are integrally cast by the gradient composite casting method described in any one of claims 1 to 7. The cutting edge part is the working part, the cutter body part is the matrix part, and the connection part between the cutting edge part and the cutter body part has a gradient composite structure.

10. A gradient composite casting product, characterized in that, The product is a fine crushing rod. The end and the front end of the fine crushing rod are integrally cast by the gradient composite casting method described in any one of claims 1 to 7. The front end is the working part, the end is the matrix part, and the connection part between the front end and the end has a gradient composite structure.

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