Investment casting process of curved surface steel mesh

Abstract

The invention relates to an investment casting process for a curved-surface steel mesh. The process comprises the following steps: injecting wax: injecting wax liquid into a plane steel mesh mold to form a wax mold; a tree group is formed, specifically, the wax mold is welded to a mold head to form a tree group; shell making: wrapping the surface of the tree group with a refractory material; dewaxing is conducted; roasting is performed; smelting: melting the steel into molten steel through casting equipment; casting: pouring the molten steel into the shell through casting equipment to form a tree group casting; shell shaking is conducted, specifically, a shell shaking machine is used for shaking the outer side shell of the tree group casting to be broken and fall off; cutting and grinding: cutting a die head in the tree group casting, and polishing the plane steel mesh casting; sand cleaning, wherein burnt-on sand left on the surface of the plane steel mesh casting is cleaned; overhauling: checking and repairing the plane steel mesh casting; bending is conducted, specifically, the plane steel mesh casting is bent to form a curved surface steel mesh casting; and finally inspecting. According to the investment casting process of the curved steel mesh, the defect that mold splitting is difficult in the casting process of the curved steel mesh is overcome, and the production efficiency of the curved steel mesh is improved.

Description

Technical Field

[0001] The invention relates to the technical field of investment casting, in particular to an investment casting process of a curved steel mesh. Background Art

[0002] Investment casting is also called lost wax casting, which includes the processes of pressing wax, trimming wax, forming trees, dipping slurry, melting wax, roasting, pouring, vibrating shells, cutting and grinding nozzles, and cleaning sand. In the casting process, wax molds of the parts to be cast are first made with wax, and then mud is coated on the wax molds, which is the mud molds; after the mud molds are dried, they are put into hot water to melt the wax molds inside; the mud molds with melted wax molds are taken out and roasted into ceramic molds; once roasted, a pouring port is usually left when making the mud molds, and then molten metal is poured from the pouring port. After cooling, the required parts are made.

[0003] Due to its special structural characteristics, curved steel mesh products face many difficulties during investment casting: (1) Difficulty in mold separation. Most of the surface of the curved steel mesh product is a hollow grid structure. The edge of the grid structure is round and has an inclined surface. A large number of live blocks are required to achieve mold separation. Each live block will produce a parting line, resulting in poor quality of the final wax mold and low production efficiency. (2) The fluidity of molten steel is poor. The curved steel mesh product contains both flat and curved structures. During casting, due to the poor fluidity of molten steel, a large number of nozzles are required to compensate for the fluidity of the molten steel, which makes the subsequent process of cutting and grinding nozzles complicated; (3) The temperature of the molten steel is too high. In order to improve the fluidity of the molten steel, the casting temperature is generally between 1720℃ and 1740℃, which leads to the defects of insufficient pouring, cold shut and shrinkage holes in the cast curved steel mesh products. Summary of the invention

[0004] Based on this, it is necessary to provide an investment casting process for curved steel mesh in view of the special structural characteristics of curved steel mesh products and the many difficulties faced during investment casting.

[0005] An investment casting process for a curved steel mesh comprises the following steps: Wax injection, injecting wax liquid into a flat steel mesh mold to form a wax mold; Assemble trees, weld the wax pattern to the die head to form a tree group; Shell making, covering the surface of the tree group with refractory materials; Dewaxing, heating the refractory material to make the tree group melt and flow out to obtain the shell; Firing: heating the shell to high temperature to dry and solidify; Melting, melting steel into molten steel through casting equipment; Casting, pouring molten steel into the mold shell through the casting equipment to form a tree casting; Shell shaking: Use a shell shaking machine to break and remove the outer shell of the tree group casting; Cutting and grinding, cutting the die heads in tree group castings, and grinding flat steel mesh castings; Clean the sand and remove the sticky sand remaining on the surface of the flat steel mesh casting; Maintenance: check and repair flat steel mesh castings; Bending: using a bending and shaping die to bend the flat steel mesh casting to form a curved steel mesh casting; Final inspection.

[0006] The investment casting process of the curved steel mesh includes the following steps: wax injection, tree assembly, shell making, dewaxing, roasting, smelting, casting, shell vibration, cutting and grinding, sand cleaning, repair, bending and final inspection. Due to the special structure of the curved steel mesh, if the wax liquid is directly injected into the curved steel mesh mold to make a wax mold, there will be defects such as mold separation difficulties, poor fluidity of the molten steel and excessively high temperature of the molten steel in the subsequent production process, resulting in reduced production efficiency and quality of the curved steel mesh. In order to avoid the above situation, in the wax injection step, wax liquid is injected into the flat steel mesh mold to form a wax mold; then the steps of tree assembly, shell making, dewaxing, roasting, smelting, casting, shell vibration, cutting and grinding, sand cleaning, and maintenance are carried out in sequence to obtain a flat steel mesh casting; then in the bending step, the flat steel mesh casting is processed into a curved steel mesh casting, and the curved steel mesh casting is inspected in the final inspection step; the investment casting process of the curved steel mesh avoids the defects of difficulty in parting, poor fluidity of the molten steel, and excessively high temperature of the molten steel, and improves the production efficiency and quality of the curved steel mesh.

[0007] In one embodiment, the lower part of the die head is provided with a first bracket, a second bracket, a third bracket and a fourth bracket; The edge of the wax model is provided with a supporting boss that matches the first bracket, the second bracket, the third bracket and the fourth bracket; The center of the wax mold is provided with a water outlet that matches the die head.

[0008] In one embodiment, the first bracket, the second bracket, the third bracket and the fourth bracket are sequentially arranged around the lower part of the die head at intervals of 90°.

[0009] In one embodiment, a pouring cup is provided on the upper part of the die head, the cross section of the pouring cup is circular, and a first reinforcing rod and a second reinforcing rod are symmetrically provided on the outer side of the pouring cup, and the first reinforcing rod and the second reinforcing rod are both arranged to be inclined downward.

[0010] In one embodiment, wrapping the refractory material on the surface of the tree group includes: The first layer is coated with zirconium slurry, sanded, and dried. The viscosity of the slurry is 45S-50S, the sanding type is 100-120 mesh zirconium sand, and the drying time is 8H-10H; In the second layer, apply mullite slurry, sprinkle sand, and dry. The slurry viscosity is 25S-30S, the sanding type is 30-60 mesh mullite sand, and the drying time is 10H-14H; On the third layer, mullite slurry is applied, sanded, and dried, wherein the slurry viscosity is 14S-16S, the sanding type is 16-30 mesh mullite sand, and the drying time is 10H-14H; On the fourth layer, mullite slurry is applied, sanded, and dried, wherein the slurry viscosity is 14S-16S, the sanding type is 16-30 mesh mullite sand, and the drying time is 10H-14H; Mullite slurry is applied to the sealing layer and dried, wherein the slurry viscosity is 10S-12S and the drying time is 10H-14H.

[0011] In one embodiment, the casting equipment includes a smelting furnace and a rotating device, and the rotating device is arranged adjacent to the smelting furnace; The smelting furnace is used to melt steel into molten steel, and the molten steel is introduced into the rotating device for casting; The rotating device is used to drive the shell to rotate during the casting process.

[0012] In one embodiment, the rotating device includes a speed controller, the smelting furnace includes a molten steel flow rate sensor, and the speed controller and the molten steel flow rate sensor are electrically connected; The molten steel flow rate sensor is used to obtain the real-time flow rate of the molten steel; The rotation speed controller is used to control the rotation speed of the rotating device according to the real-time flow speed.

[0013] In one embodiment, the casting temperature of the molten steel is 1600°C-1620°C.

[0014] In one embodiment, the bending and shaping mold includes an upper mold and a lower mold; The lower die is provided with a circular boss, the circular boss is provided with a positioning through hole, and a positioning column matching the steel mesh is installed on the positioning through hole; The upper die is provided with a circular groove matching the circular boss.

[0015] In one of the embodiments, the bending and shaping mold further includes an upper pressing plate and a lower pressing plate, wherein the upper pressing plate is fixedly connected to the upper mold, and the lower pressing plate is fixedly connected to the lower mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the process flow of the investment casting process of the curved steel mesh of the present invention; Figure 2 It is a structural schematic diagram of a die head in the investment casting process of a curved steel mesh of the present invention; Figure 3 It is a structural schematic diagram of a tree group in the investment casting process of the curved steel mesh of the present invention; Figure 4 It is a structural schematic diagram of a casting device in the investment casting process of a curved steel mesh of the present invention; Figure 5 It is a structural schematic diagram of a bending and shaping mold in the investment casting process of a curved steel mesh of the present invention; Figure 6 for Figure 5 Schematic diagram of the structure of the middle and lower molds; Figure 7 for Figure 5 Schematic diagram of the matching structure between the middle and lower molds and the curved steel mesh casting; Figure 8 It is a structural schematic diagram of a curved steel mesh casting; Fig. 9 for Figure 5 Schematic diagram of the structure of the middle and upper mold; Fig.10 for Figure 5 Schematic diagram of the matching structure between the middle upper mold and the curved steel mesh casting; Among them, 10 is a die head, 20 is a wax mold, 30 is a casting equipment, 40 is a bending and shaping mold, 50 is a curved steel mesh, 60 is a water outlet, 11 is a first bracket, 12 is a second bracket, 13 is a third bracket, 14 is a fourth bracket, 15 is a first reinforcing rod, 16 is a second reinforcing rod, 21 is a supporting boss, 31 is a melting furnace, 32 is a rotating device, 41 is an upper mold, 42 is a lower mold, 43 is an upper pressure plate, 44 is a lower pressure plate, 411 is a circular groove, 421 is a circular boss, 4211 is a positioning through hole, and 4212 is a positioning column. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0018] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may also be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only."

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0020] The invention discloses an investment casting process for a curved steel mesh.

[0021] like Figure 1 As shown, the investment casting process of the curved steel mesh includes the following steps: Wax injection, injecting wax liquid into a flat steel mesh mold to form a wax mold; Assemble trees, weld the wax pattern to the die head to form a tree group; Shell making, covering the surface of the tree group with refractory materials; Dewaxing, heating the refractory material to make the tree group melt and flow out to obtain the shell; Firing: heating the shell to high temperature to dry and solidify; Melting, melting steel into molten steel through casting equipment; Casting, pouring molten steel into the mold shell through the casting equipment to form a tree casting; Shell shaking: Use a shell shaking machine to break and remove the outer shell of the tree group casting; Cutting and grinding, cutting the die heads in tree group castings, and grinding flat steel mesh castings; Clean the sand and remove the sticky sand remaining on the surface of the flat steel mesh casting; Maintenance: check and repair flat steel mesh castings; Bending: using a bending and shaping die to bend the flat steel mesh casting to form a curved steel mesh casting; Final inspection.

[0022] The investment casting process of the curved steel mesh includes the following steps: wax injection, tree assembly, shell making, dewaxing, roasting, smelting, casting, shell vibration, cutting and grinding, sand cleaning, repair, bending and final inspection. Due to the special structure of the curved steel mesh, if the wax liquid is directly injected into the curved steel mesh mold to make a wax mold, there will be defects such as mold separation difficulties, poor fluidity of the molten steel and excessively high temperature of the molten steel in the subsequent production process, resulting in reduced production efficiency and quality of the curved steel mesh. In order to avoid the above situation, in the wax injection step, wax liquid is injected into the flat steel mesh mold to form a wax mold; then the steps of tree assembly, shell making, dewaxing, roasting, smelting, casting, shell vibration, cutting and grinding, sand cleaning, and maintenance are carried out in sequence to obtain a flat steel mesh casting; then in the bending step, the flat steel mesh casting is processed into a curved steel mesh casting, and the curved steel mesh casting is inspected in the final inspection step; the investment casting process of the curved steel mesh avoids the defects of difficulty in parting, poor fluidity of the molten steel, and excessively high temperature of the molten steel, thereby improving the production efficiency and quality of the curved steel mesh.

[0023] like Figures 2 to 3 As shown, the lower part of the die head 10 is provided with a first bracket 11, a second bracket 12, a third bracket 13 and a fourth bracket 14, the edge of the wax mold 20 is provided with a supporting boss 21 that matches the first bracket 11, the second bracket 12, the third bracket 13 and the fourth bracket 14, and the center of the wax mold 20 is provided with a water inlet 60 that matches the die head 10. The water inlet 60 can guide the flow of molten steel, reduce the impact force of the molten steel, and also has the function of shrinkage compensation. The supporting boss 21 can support the die head 10 to prevent the wax mold 20 from deforming.

[0024] Further, the first bracket 11, the second bracket 12, the third bracket 13 and the fourth bracket 14 are sequentially arranged at intervals of 90° around the lower portion of the die head 10. The first bracket 11, the second bracket 12, the third bracket 13 and the fourth bracket 14 are sequentially arranged at intervals of 90° around the lower portion of the die head 10, so that the support boss 21 that cooperates with the first bracket 11, the second bracket 12, the third bracket 13 and the fourth bracket 14 can be evenly stressed, thereby improving the structural stability of the tree group.

[0025] Furthermore, a pouring cup is provided on the upper part of the die head 10, and the cross section of the pouring cup is circular. A first reinforcing rod 15 and a second reinforcing rod 16 are symmetrically provided on the outer side of the pouring cup, and the first reinforcing rod 15 and the second reinforcing rod 16 are both arranged to be tilted downward. The arrangement of the first reinforcing rod 15 and the second reinforcing rod 16 can improve the structural strength of the die head 10, so that the die head 10 is not easily damaged.

[0026] Wherein, wrapping the refractory material on the surface of the wax mold further comprises: The first layer is coated with zirconium slurry, sprinkled with sand, and dried, wherein the slurry viscosity is 45S-50S, the sanding type is 100-120 mesh zirconium sand, and the drying time is 8H-10H; the second layer is coated with mullite slurry, sprinkled with sand, and dried, wherein the slurry viscosity is 25S-30S, the sanding type is 30-60 mesh mullite sand, and the drying time is 10H-14H; the third layer is coated with mullite slurry, sprinkled with sand, and dried, wherein the slurry viscosity is 14S-16S, the sanding type is 16-30 mesh mullite sand, and the drying time is 10H-14H; the fourth layer is coated with mullite slurry, sprinkled with sand, and dried, wherein the slurry viscosity is 14S-16S, the sanding type is 16-30 mesh mullite sand, and the drying time is 10H-14H; the sealing layer is coated with mullite slurry and dried, wherein the slurry viscosity is 10S-12S, and the drying time is 10H-14H. By performing slurry dipping, sanding and drying on the first layer, the second layer, the third layer and the fourth layer respectively, the structural strength of the refractory material can be improved, and the deformation of the refractory material during the heating process that affects the quality of the flat steel mesh casting can be avoided.

[0027] like Figure 4 As shown, the casting equipment 30 includes a melting furnace 31 and a rotating device 32, and the rotating device 32 is arranged adjacent to the melting furnace 31; the melting furnace 31 is used to melt steel into molten steel, and the molten steel is introduced into the rotating device 32 for casting; the rotating device 32 is used to drive the shell to rotate during the casting process to improve the fluidity of the molten steel during the casting process. The rotating device 32 is arranged adjacent to the melting furnace 31, so that the molten steel inside the melting furnace 31 can be quickly introduced into the shell, thereby improving the efficiency of casting.

[0028] Furthermore, the melting furnace 31 is provided with a molten steel guide groove that matches the rotating device 32, through which the molten steel in the melting furnace 31 can be quickly introduced into the rotating device 32. Since a pouring cup is provided on the upper part of the die head 10, and the cross section of the pouring cup is circular, the end of the molten steel guide groove is located directly above the pouring cup, so during the rotation of the rotating device 32, the molten steel flowing out of the molten steel guide groove will be accurately introduced into the mold shell due to the effect of gravity, thereby completing the casting step.

[0029] Furthermore, the rotating device 32 includes a speed controller, and the smelting furnace 31 includes a molten steel flow rate sensor, and the speed controller and the molten steel flow rate sensor are electrically connected; the molten steel flow rate sensor is used to obtain the real-time flow rate of the molten steel; and the speed controller is used to control the speed of the rotating device 32 according to the real-time flow rate of the molten steel. It should be noted that as the molten steel level inside the smelting furnace 31 continues to change, the real-time flow rate of the molten steel exported from the smelting furnace 31 to the rotating device 32 also changes, and the rotation speed of the rotating device 32 needs to be adjusted according to the real-time flow rate of the molten steel, thereby improving the stability of the casting process and the quality of the flat steel mesh casting. By setting a speed controller on the rotating device 32 and a molten steel flow rate sensor on the smelting furnace 31, the accuracy of casting and product stability can be significantly improved.

[0030] Furthermore, the casting temperature of the molten steel is 1600°C-1620°C. The casting temperature of the molten steel is set to 1600°C-1620°C, so that the molten steel has good fluidity, while avoiding shrinkage defects caused by excessively high molten steel temperature. Due to the good fluidity of the molten steel, the wax mold 20 can be connected to the die head 10 through a water inlet 60, which reduces the processing workload of the steps of cutting, sand cleaning and maintenance, improves the production efficiency of the curved steel mesh casting, and reduces the defects of the curved steel mesh casting such as insufficient pouring, cold shut, shrinkage, etc.

[0031] like Figures 5 to 10 As shown, the bending and shaping mold 40 includes an upper mold 41 and a lower mold 42; the lower mold 42 is provided with a circular boss 421, the circular boss 421 is provided with a positioning through hole 4211, and a positioning column 4212 matching the steel mesh is installed on the positioning through hole 4211; the upper mold 41 is provided with a circular groove 411 matching the circular boss 421.

[0032] It should be noted that the shape of the positioning column 4212 matches the mesh shape of the steel mesh. When the steel mesh is installed on the lower mold 42, the steel mesh is limited by the positioning column 4212 and does not move, which improves the process stability during the bending process. In the bending step, the flat steel mesh casting is first installed on the lower mold 42, and then the upper mold 41 is controlled to move toward the lower mold 42 and squeeze the flat steel mesh casting. Due to the mutual cooperation of the circular boss 421 and the circular groove 411, the flat steel mesh casting can be bent to form a curved steel mesh casting 50.

[0033] Furthermore, the bending shaping mold further includes an upper pressing plate 43 and a lower pressing plate 44, wherein the upper pressing plate 43 is fixedly connected to the upper mold 41, and the lower pressing plate 44 is fixedly connected to the lower mold 42. The upper pressing plate 43 and the lower pressing plate 44 can support the upper mold 41 and the lower mold 42 respectively to improve the process stability of the bending step.

[0034] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An investment casting process for a curved steel mesh, characterized in that: The following steps are involved: Wax injection, injecting wax liquid into a flat steel mesh mold to form a wax mold; Assemble trees, weld the wax pattern to the die head to form a tree group; Shell making, covering the surface of the tree group with refractory materials; Dewaxing, heating the refractory material to melt the tree group and get the shell; Firing: heating the shell to high temperature to dry and solidify; Melting, melting steel into molten steel through casting equipment; Casting, pouring molten steel into the mold shell through the casting equipment to form a tree casting; Shell shaking: Use a shell shaking machine to break and remove the outer shell of the tree group casting; Cutting and grinding, cutting the die heads in tree group castings, and grinding flat steel mesh castings; Clean the sand and remove the sticky sand remaining on the surface of the flat steel mesh casting; Maintenance: check and repair flat steel mesh castings; Bending: using a bending and shaping die to bend the flat steel mesh casting to form a curved steel mesh casting; Final inspection.

2. The investment casting process of curved steel mesh according to claim 1, characterized in that: The lower part of the die head is provided with a first bracket, a second bracket, a third bracket and a fourth bracket; The edge of the wax model is provided with a supporting boss that matches the first bracket, the second bracket, the third bracket and the fourth bracket; The center of the wax mold is provided with a water outlet that matches the die head.

3. The investment casting process of curved steel mesh according to claim 2, characterized in that: The first bracket, the second bracket, the third bracket and the fourth bracket are sequentially arranged around the lower part of the die head at intervals of 90°.

4. The investment casting process of curved steel mesh according to claim 3, characterized in that: A pouring cup is provided on the upper part of the die head, and the cross section of the pouring cup is circular. A first reinforcing rod and a second reinforcing rod are symmetrically provided on the outer side of the pouring cup, and the first reinforcing rod and the second reinforcing rod are both arranged to tilt downward.

5. The investment casting process of curved steel mesh according to claim 1, characterized in that: Said wrapping of refractory material on the surface of the tree group comprises: The first layer is coated with zirconium slurry, sanded, and dried. The viscosity of the slurry is 45S-50S, the sanding type is 100-120 mesh zirconium sand, and the drying time is 8H-10H; In the second layer, apply mullite slurry, sprinkle sand, and dry. The slurry viscosity is 25S-30S, the sanding type is 30-60 mesh mullite sand, and the drying time is 10H-14H; On the third layer, mullite slurry is applied, sanded, and dried, wherein the slurry viscosity is 14S-16S, the sanding type is 16-30 mesh mullite sand, and the drying time is 10H-14H; On the fourth layer, mullite slurry is applied, sanded, and dried, wherein the slurry viscosity is 14S-16S, the sanding type is 16-30 mesh mullite sand, and the drying time is 10H-14H; Mullite slurry is applied to the sealing layer and dried, wherein the slurry viscosity is 10S-12S and the drying time is 10H-14H.

6. The investment casting process of curved steel mesh according to claim 1, characterized in that: The casting equipment includes a smelting furnace and a rotating device, and the rotating device is arranged adjacent to the smelting furnace; The smelting furnace is used to melt steel into molten steel, and the molten steel is introduced into the rotating device for casting; The rotating device is used to drive the shell to rotate during the casting process.

7. The investment casting process of curved steel mesh according to claim 6, characterized in that: The rotating device includes a speed controller, the smelting furnace includes a molten steel flow rate sensor, and the speed controller and the molten steel flow rate sensor are electrically connected; The molten steel flow rate sensor is used to obtain the real-time flow rate of the molten steel; The rotation speed controller is used to control the rotation speed of the rotating device according to the real-time flow speed.

8. The investment casting process of curved steel mesh according to claim 7, characterized in that: The casting temperature of the molten steel is 1600°C-1620°C.

9. The investment casting process of curved steel mesh according to claim 1, characterized in that: The bending and shaping die comprises an upper die and a lower die; The lower die is provided with a circular boss, the circular boss is provided with a positioning through hole, and a positioning column matching the steel mesh is installed on the positioning through hole; The upper die is provided with a circular groove matching the circular boss.

10. The investment casting process of curved steel mesh according to claim 9, characterized in that: The bending and shaping mold also includes an upper pressing plate and a lower pressing plate, wherein the upper pressing plate is fixedly connected to the upper mold, and the lower pressing plate is fixedly connected to the lower mold.

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