Full mold casting process of three-quarter tire mold casting
By setting up the 'S' shaped foam support and foam strip auxiliary blocks on the ductile iron membrane casting model, and using the bottom-injection casting system, the problem of the larger casting opening and the difficulty of removing the inner gate is solved, and the casting shape is realized Stability and convenience of production.
Patent Information
- Application Number
- CN202411309307.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-19
- Publication Date
- 2025-02-11
AI Technical Summary
The three-quarters of the ring structure of ductile iron membrane castings is prone to widening openings, and the inner gate is difficult to remove, resulting in the deformation and production difficulty of castings.
When making the model, set the 'Si' shaped foam support and foam strip auxiliary block, and set the inner gate of the casting system at the 'Si' shaped foam support, and use a bottom pouring pouring system to ensure the stable filling of the molten iron.
Effectively prevent deformation of the casting opening and profile surface, simplify the internal gate removal process, and improve the shape stability and product quality of the casting.
Smart Images
Figure CN119407104A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of full-mold casting, and particularly relates to a full-mold casting process for three-quarter die-casting mold-like castings. Background Art
[0002] The structure of the ductile iron die-casting mold-like casting is in the shape of a three-quarter ring. Such a structure is prone to the problem of the opening becoming larger. Once the opening becomes larger, it cannot be repaired and will be scrapped. Moreover, the two sides of the casting surface and the bottom surface are relatively thin. After the model allowance is set, it is only 20 mm, and it is prone to deformation during the dipping process and the molding sand embedding process, and the repair difficulty is relatively large.
[0003] The openings on both sides of the casting surface and the bottom surface of such a structure are 95 mm, and the wall thickness on both sides is only 20 mm. A sprue is set in the middle of the opening. It is difficult to remove the sprue in the later stage. There is a certain difficulty in designing the gating system for such a structure.
[0004] In the existing production process of ductile iron die-casting mold-like castings, due to the lack of good control measures for the "three-quarter" ring structure and the thin structure of the upper and lower surfaces, the opening is prone to deformation. Serious deformation not only has extremely high welding repair costs but also affects the later use of the casting, and even leads to the scrapping of the casting. On the other hand, due to the thin structure of the ductile iron die-casting mold-like casting, there are limitations in the setting of the sprue. Therefore, while seeking to ensure that the deformation of the casting is within a controllable range, we need to solve the problem of the setting of the gating system. Therefore, it is very necessary to solve this problem. Summary of the Invention
[0005] In view of this, the purpose of the present invention is to provide a full-mold casting process for three-quarter die-casting mold-like castings to solve the problems that the opening of the three-quarter ring die-casting mold-like casting is prone to becoming larger and the sprue is difficult to remove.
[0006] Based on the above purpose, the present invention provides a full-mold casting process for three-quarter die-casting mold-like castings. The casting is performed using a model of a three-quarter die-casting mold-like casting. The model of the three-quarter die-casting mold-like casting is in the shape of a three-quarter arc, and it includes two vertical ribs of three-quarter arcs arranged at intervals. The bottoms of the two vertical ribs are connected together by a bottom plate, and the ends of the two vertical ribs are fixed by a vertical mounting seat. Both the upper and lower ends of the mounting seat protrude. It is characterized by including the following steps: Step 1, when making the model, a "plus" shaped foam support is set at the opening of the three-quarter ring die-casting mold; Step 2, the two vertical ribs of the model are connected by foam strip auxiliary blocks; Step 3, the sprue of the gating system is set at the "plus" shaped foam support. The middle circle of the model is all a machined surface as the casting surface, and the middle circle of the local bosses on the bottom surface of the model is used as the slag removal surface. A bottom gating system is adopted to make the molten iron fill the mold smoothly, and a pot platform is placed in the sprue. Step 4: Melting the casting material of the gating system, and pouring the melted casting material into the mold through the gating system to obtain three-quarter die-casting mold castings; Step 5: Stress-relieving annealing the three-quarter die-casting mold castings to obtain the final castings.
[0007] Preferably, the casting material in Step 4 is specifically: C 3.5 - 3.7%, Si 2.0 - 2.5%, Mn 0.4 - 0.6%, Cr 0.1 - 0.3%, Cu 0.6 - 0.8%, Mg 0.04 - 0.07%, Re 0.02 - 0.04%, P ≤ 0.05%, S ≤ 0.015%, and the rest is Fe.
[0008] Preferably, the stress-relieving annealing in Step 5 is specifically: First, heat up to 540 - 570°C at a rate of ≤60°C / h, then hold for 8 - 12 h, and finally cool down to 200°C at a rate of ≤40°C / h, and then air-cool to room temperature.
[0009] Preferably, the "plus" - shaped foam support is composed of two horizontal long strips and one vertical long strip to form a "plus" shape, and the height and width of the long strips are both 100 mm.
[0010] Preferably, support blocks are distributed on both the top and bottom of the "plus" - shaped foam support. The top surface of the support block on the top is in the same plane as the top surface of the mounting seat, and the bottom surface of the support block on the bottom is in the same plane as the bottom surface of the mounting seat.
[0011] Preferably, the long horizontal strip of the "plus" - shaped foam support is connected to the inside of the three-quarter ring die-casting mold, the short horizontal strip of the "plus" - shaped foam support is connected to the opening of the three-quarter ring die-casting mold, and one end of the vertical long strip of the "plus" - shaped foam support is connected to the inside of the three-quarter ring die-casting mold.
[0012] Preferably, foam strip auxiliary blocks are distributed at both the upper and lower ends of the two vertical ribs of the mold. The top surface of the foam strip auxiliary blocks at the upper ends of the two vertical ribs is in the same plane as the top surface of the mounting seat, and the bottom surface of the foam strip auxiliary blocks at the lower ends of the two vertical ribs is in the same plane as the bottom surface of the mounting seat.
[0013] Preferably, the foam strip auxiliary block is in the shape of a cuboid, with its long ends respectively connected to the two vertical ribs of the mold, and its dimensions are 125 * 40 * 37.5 mm.
[0014] Preferably, the ingate of the gating system is arranged on the "plus" - shaped foam support. Its cross - section is φ50mm. Beneficial effects of the present invention: To prevent the opening of the casting and the deformation of the upper opening, a "plus" - shaped foam support with a size of 100 * 100mm is set at the opening of the three - quarter - ring die during model making, preventing the model from deforming during the dip - coating process and the molding sand - burying process.
[0015] In the present invention, two vertical ribs of the model are connected by foam strip auxiliary blocks. On the one hand, it prevents damage caused by the scouring of the coating during the dip - coating process and deformation caused by the extrusion of the outer and inner sand during the molding sand - burying process. On the other hand, during pouring, the molten iron will enter another vertical rib through the foam strip auxiliary block, greatly improving the filling of the vertical rib.
[0016] In the present invention, by arranging the ingate of the gating system at the "plus" - shaped foam support, the "plus" - shaped foam support and the ingate are directly removed together later, without the need to remove the gate on the casting; the entire middle circle of the model is a machined surface as the mold surface, and a local boss in the middle circle of the bottom surface of the model is used as the slag - discharging surface. A bottom - pouring gating system is adopted to make the molten iron fill smoothly, facilitating the full floating of the slag in the molten iron and avoiding other defects such as cold shuts and misruns; the hearth placed in the sprue improves the filling speed of the molten iron during pouring, enables the foam to gasify and decompose quickly, and ensures the complete filling of the casting.
[0017] During the melting process of the present invention, by adjusting the chemical composition of the molten metal of the pouring material, the carbon equivalent of the molten iron is increased, which is in the hypoeutectic composition, and the composition ratio of alloying elements is appropriately controlled, thereby reducing the shrinkage tendency of the molten iron and helping to improve the product quality of ductile iron die - casting parts.
[0018] The stress - relieving annealing of the present invention has a low stress - relieving heating temperature, no phase transformation during annealing, eliminates the residual stress in the casting, stabilizes the size and shape of the casting, and removes the support after eliminating the internal residual stress of the casting, preventing the opening of the die - casting part from becoming larger when the support is removed at the beginning. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0020] Figure 1 is the bottom schematic diagram of the whole of the present invention; Figure 2 is the front schematic diagram of the whole of the present invention; Figure 3It is a stress relief annealing process curve diagram of the present invention.
[0021] The markings in the figure are: 1- vertical rib, 2- mounting seat, 3- boss, 4- "S" shaped foam support, 5- foam strip auxiliary block, 6- inner gate, 7- support block, 8- pouring system. DETAILED DESCRIPTION
[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.
[0023] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0024] like Figures 1 to 3 As shown, a full-mold casting process for three-quarters fetal membrane castings is cast using a three-quarters fetal membrane casting model, the three-quarters fetal membrane casting model is in the shape of a three-quarter arc, and includes two three-quarter arc vertical ribs 1 arranged at intervals, the bottoms of the two vertical ribs 1 are connected together by a bottom plate, and the ends of the two vertical ribs 1 are fixed by a vertical mounting seat 2, and the upper and lower ends of the mounting seat are protruding, and it is characterized in that it includes the following steps: S1. When making the model, a "plus" - shaped foam support 4 is set at the opening of the three - quarter - ring die - casting mold. The "plus" - shaped foam support 4 is composed of two horizontal long strips and one vertical long strip to form a "plus" shape. The height and width of the long strips are both 100 mm. The long horizontal strip of the "plus" - shaped foam support 4 is connected to the inside of the three - quarter - ring die - casting mold. The short horizontal strip of the "plus" - shaped foam support 4 is connected to the opening of the three - quarter - ring die - casting mold. One end of the vertical long strip of the "plus" - shaped foam support 4 is connected to the inside of the three - quarter - ring die - casting mold. In this way, the opening of the model can be well supported, preventing the model from deforming during the dip - coating process and the sand - embedding process for molding. Support blocks 7 are distributed on both the top and bottom of the "plus" - shaped foam support 4. The top surface of the support block 7 on the top is in the same plane as the top surface of the mounting seat 2, and the bottom surface of the support block 7 on the bottom is in the same plane as the bottom surface of the mounting seat 4. In this way, the overall deformation of the casting in the up - and - down direction is prevented. S2. The two vertical ribs 1 of the model are connected by foam - strip auxiliary blocks 5. The foam - strip auxiliary blocks 5 are distributed at both the upper and lower ends of the two vertical ribs 1 of the model. On the one hand, it can prevent damage caused by the scouring of the coating during the dip - coating process and deformation caused by the extrusion of the outer and inner sand during the sand - embedding process for molding. On the other hand, during pouring, the molten iron will enter the other vertical rib 1 through the foam - strip auxiliary block, which greatly improves the filling of the vertical rib 1. The top surface of the foam - strip auxiliary blocks 5 at the upper ends of the two vertical ribs 2 is in the same plane as the top surface of the mounting seat 2, and the bottom surface of the foam - strip auxiliary blocks 5 at the lower ends of the two vertical ribs 1 is in the same plane as the bottom surface of the mounting seat 2. In this way, the overall deformation of the casting in the up - and - down direction is prevented. The foam - strip auxiliary block 5 is in the shape of a cuboid, and its two long ends are respectively connected to the two vertical ribs of the model. Its dimensions are 125 * 40 * 37.5 mm.
[0025] S3. The ingate 6 of the gating system is set at the "plus" - shaped foam support 4. The entire middle circle of the model is a machined surface as the mold surface, and the middle - circle local boss 3 at the bottom of the model is used as the slag - discharging surface. A bottom - gating system is adopted to make the molten iron fill smoothly, and a pot - shaped platform is placed in the sprue. In this way, later, the "plus" - shaped foam support 4 and the ingate 6 can be directly removed together, and there is no need to remove the gate on the casting. Adopting a bottom - gating system makes the molten iron fill smoothly, facilitating the full floating of the slag in the molten iron and avoiding other defects such as cold shuts and misruns. The pot - shaped platform placed in the sprue improves the filling speed of the molten iron during pouring, enables the foam to quickly gasify and decompose, and ensures the complete filling of the casting. S4, melt the pouring material of the pouring system, C 3.5-3.7%, Si 2.0-2.5%, Mn 0.4-0.6%, Cr0.1-0.3%, Cu 0.6-0.8%, Mg 0.04-0.07%, Re 0.02-0.04%, P≤0.05%, S≤0.015%, and the rest is Fe. The smelted pouring material is poured into the mold through the pouring system to obtain three-quarters of the fetal membrane casting; increase the carbon equivalent of the molten iron to be in the hypoeutectic composition, and properly control the composition ratio of the alloying elements, so as to reduce the shrinkage tendency of the molten iron, which is helpful to improve the product quality of ductile iron fetal membrane castings.
[0026] S5, stress relief annealing is performed on three quarters of the fetal membrane castings, first at a rate of ≤60℃ / h to 540-570℃, then kept warm for 8-12h, and finally cooled to 200℃ at a rate of ≤40℃ / h, and then air-cooled to room temperature to obtain the final casting; the stress relief heating temperature is low, and there is no structural transformation during the annealing process, which eliminates the residual stress in the casting and stabilizes the size and shape of the casting. After annealing, the residual stress inside the casting is eliminated before the support is removed to prevent the opening of the fetal membrane casting from becoming larger due to the removal of the support at the beginning.
[0027] In this embodiment, the “R”-shaped foam support 4 is provided and the inner gate 6 is directly provided on the “R”-shaped foam support 4, thereby ensuring that three-quarters of the fetal membrane casting is free of deformation and the filling is intact.
[0028] It should be understood by those skilled in the art that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.
Claims
1. A full-mold casting process for three-quarters fetal membrane castings, using a three-quarters fetal membrane casting model for pouring, the three-quarters fetal membrane casting model is a three-quarter arc shape, which includes two three-quarter arc vertical ribs arranged at intervals, the bottoms of the two vertical ribs are connected together by a bottom plate, the ends of the two vertical ribs are fixed by a vertical mounting seat, and the upper and lower ends of the mounting seat are protruding, characterized in that It includes the following steps: Step 1, set a "plus" - shaped foam support at the opening of the three - quarter - ring casting mold during mold making; Step 2, connect the two vertical ribs of the mold with foam strip auxiliary blocks; Step 3, set the ingate of the gating system at the "plus" - shaped foam support. The entire middle circle of the mold is used as the molding surface, and the middle - circle local boss at the bottom of the mold is used as the slag - discharging surface. Adopt a bottom - pouring gating system to make the molten iron fill the mold smoothly, and place a hearth in the sprue; Step 4, melt the gating material of the gating system, and pour the melted gating material into the mold through the gating system to obtain a three - quarter - mold - type casting; Step 5, perform stress - relieving annealing on the three - quarter - mold - type casting to obtain the final casting.
2. A full mold casting process for three-quarters fetal membrane castings according to claim 1, characterized in that: The specific gating material in Step 4 is: C 3.5 - 3.7%, Si 2.0 - 2.5%, Mn 0.4 - 0.6%, Cr 0.1 - 0.3%, Cu 0.6 - 0.8%, Mg 0.04 - 0.07%, Re 0.02 - 0.04%, P≤0.05%, S≤0.015%, and the rest is Fe.
3. A full mold casting process for three-quarter fetal membrane castings according to claim 1, characterized in that: The specific stress - relieving annealing in Step 5 is: First, heat to 540 - 570°C at a rate of ≤60°C / h, then hold for 8 - 12 h, and finally cool to 200°C at a rate of ≤40°C / h, and then air - cool to room temperature.
4. A full mold casting process for three-quarter fetal membrane castings according to claim 1, characterized in that: The "plus" - shaped foam support is composed of two horizontal long strips and one vertical long strip to form a "plus" shape. The height and width of the long strips are both 100 mm.
5. A full mold casting process for three-quarters fetal membrane castings according to claim 4, characterized in that: Support blocks are distributed on both the top and bottom of the "plus" - shaped foam support. The top surface of the support blocks on the top is in the same plane as the top surface of the mounting seat, and the bottom surface of the support blocks on the bottom is in the same plane as the bottom surface of the mounting seat.
6. A full mold casting process for three-quarter fetal membrane castings according to claim 4, characterized in that: The long horizontal strip of the "plus" - shaped foam support is connected inside the three - quarter - ring casting mold, the short horizontal strip of the "plus" - shaped foam support is connected to the opening of the three - quarter - ring casting mold, and one end of the vertical long strip of the "plus" - shaped foam support is connected inside the three - quarter - ring casting mold.
7. A full mold casting process for three-quarter fetal membrane castings according to claim 1, characterized in that: Foam strip auxiliary blocks are distributed at both the upper and lower ends of the two vertical ribs of the mold. The top surface of the foam strip auxiliary blocks at the upper ends of the two vertical ribs is in the same plane as the top surface of the mounting seat, and the bottom surface of the foam strip auxiliary blocks at the lower ends of the two vertical ribs is in the same plane as the bottom surface of the mounting seat.
8. A full mold casting process for three-quarter fetal membrane castings according to claim 7, characterized in that: The foam strip auxiliary block is in the shape of a cuboid, with its long ends respectively connected to the two vertical ribs of the mold, and its dimensions are 125 * 40 * 37.5 mm.
9. A full mold casting process for three-quarter fetal membrane castings according to claim 4, characterized in that: The ingate of the gating system is set on the "plus" - shaped foam support, and its cross - section is φ50 mm.