Casting structure for in-mold inoculation

Abstract

The utility model discloses a pouring structure for in-mold inoculation. The structure comprises a pouring system and a casting cavity communicated with the pouring system, the pouring system comprises a straight pouring gate, a transverse pouring gate, an in-mold inoculation structure, a first pouring gate, a foam filter, a second pouring gate and an inner pouring gate; the sprue is located in the middle of the cross gate and perpendicularly connected with the cross gate, the in-mold inoculation structure is connected with the cross gate, the first pouring gate and the second pouring gate are arranged in an up-and-down overlapping mode in the axial direction of the sprue, the foam filter is located between the first pouring gate and the second pouring gate, and the foam filter is located between the first pouring gate and the second pouring gate. The first pouring gate, the second pouring gate and the foam filter are communicated with the tail end of the cross gate; one end of the inner pouring gate is transversely communicated with the second pouring gate, and the other end of the inner pouring gate is communicated with a casting cavity; the method has the advantages that the method is suitable for instantaneous inoculation of thick and large-section nodular cast iron, molten iron pouring is more stable, and therefore casting defects are reduced.

Description

Technical Field

[0001] This application relates to the field of casting metal technology, specifically to an in-mold inoculation casting structure for a thick-section, high-oil-pressure ductile iron mold. Background Technology

[0002] In the field of high-end injection molding and equipment technology, high-precision, stable, and efficient production in high-speed injection molding processes all require high-quality, high-pressure ductile iron mold castings as a foundation. Large-size hydraulic ductile iron mold castings, as key load-bearing components, directly affect the stability, molding speed, molding accuracy, and service life of injection molding equipment. Therefore, the quality and technical level of high-pressure ductile iron mold components are crucial to the entire injection molding process. When the mold wall thickness exceeds a certain dimension, the molding quality of thick-section ductile iron parts will decrease.

[0003] like Figure 1-2 The image shows a high-pressure ductile iron template casting. The blank weighs 8250 kg, the gating weight is 9150 kg, the material is ductile iron QT450-10A, the dimensions are 2022 mm × 1660 mm × 1020 mm, and the maximum wall thickness is 365 mm. It belongs to a large, thick-section ductile iron casting. The casting body a has eight casting holes that directly serve as cylinder holes a1. Casting defects such as shrinkage cavities and porosity, as well as oil seepage and leakage, are not permitted. Furthermore, the hole wall machining requirements are also particularly high, with an inner surface roughness requirement of Ra0.4~0.8um, while simultaneously meeting the 20Mpa oil pressure requirement, which cannot be achieved by conventional casting methods. The 365mm thick section of this casting product has two Ф30mm through holes a2 connected to the cylinder hole a1, which are directly used as oil passages for high-pressure oil. These through holes a2 are also not allowed to have casting defects such as shrinkage cavities or porosity, as well as oil seepage or leakage, which cannot be achieved by conventional casting methods.

[0004] In the casting process, the inoculation treatment technology plays a crucial role in cast iron production. It has become a vital step in producing high-quality cast iron parts and an effective measure for producing thick-walled, complex, and high-strength cast iron, as well as improving the machinability of castings. The effect of the inoculant during the inoculation process is time-sensitive; that is, the inoculation effect weakens over time. Therefore, the closer the inoculant is added to the molten iron is to its solidification time, the better its effect. Currently, most foundries use a multiple inoculation method. This multiple inoculation approach not only increases the number of steps but also requires a large amount of inoculant, increasing the production cost of castings.

[0005] Figure 1-2The castings shown differ from those produced for thin-walled or medium-thickness (small and medium-sized) ductile iron castings. The inoculation method for these thick-section ductile iron castings is quite different. Generally, small and medium-sized ductile iron castings use a combination of in-ladle inoculation and in-flow inoculation. However, for thick-section ductile iron castings, due to the large volume of molten iron poured, pouring is generally done in a pouring basin, making in-flow inoculation difficult. Because of the long pouring and solidification time, slow cooling rate, and large tendency to decay, it is even more important to strengthen the inoculation. It can be said that the success or failure of inoculation plays a crucial role for thick-section ductile iron castings.

[0006] Furthermore, due to their large cross-sectional dimensions, thick-section ductile iron is prone to defects such as shrinkage cavities, porosity, and slag inclusions during the casting process. Therefore, the gating system has special requirements. The gating system must ensure high fluidity, high filling capacity, and temperature uniformity of the molten iron, ensuring uniform temperature during the pouring process and avoiding defects caused by excessive temperature differences. A stable pouring speed must be controlled to maintain a steady flow of molten iron, avoiding defects caused by excessively fast or slow pouring speeds. Utility Model Content

[0007] In view of the above-mentioned shortcomings of the prior art, this application provides a casting structure for instantaneous inoculation of thick-section ductile iron, which makes the pouring of molten iron more stable and thus reduces casting defects.

[0008] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows: an in-mold inoculation casting structure, which includes a casting system and a casting cavity connected thereto; the casting system includes a sprue, a runner, an in-mold inoculation structure, a first runner, a foam filter, a second runner, and an ingate; the sprue is located in the middle of the runner and is perpendicularly connected to the runner; the in-mold inoculation structure is connected to the runner; the first runner and the second runner are stacked vertically along the axial direction of the sprue; the foam filter is located between the first runner and the second runner; the first runner, the second runner, and the foam filter are connected to the tail end of the runner; one end of the ingate is laterally connected to the second runner, and the other end is connected to the casting cavity.

[0009] By adopting the above structure, this application achieves instantaneous in-mold inoculation during the pouring process by directly setting the inoculation structure within the gating system. Therefore, instantaneous inoculation can be achieved during the pouring process of the thick-section ductile iron in this application. Based on this inoculation, the inoculant can be directly placed into the mold in block form, maximizing the inoculation effect, reducing alloy usage, and allowing for the addition of different quantities and types of inoculants to produce castings with different inoculation requirements using the same molten iron, overcoming the defects caused by traditional multiple inoculation methods. Furthermore, the gating system in this application has a high degree of compatibility with the mold of the thick-section ductile iron, resulting in more stable pouring and reduced casting defects.

[0010] Furthermore, the in-mold inoculation structure is provided in at least two parts, and the two in-mold inoculation structures are symmetrically arranged on the runner with the sprue as the center. With this structure, when the molten iron enters the runner from the sprue, it splits into left and right sides, so that the in-mold inoculation structures on both sides can play a role, and instantaneous in-mold inoculation can be achieved in a more balanced way.

[0011] Furthermore, the in-mold inoculation structure is a trapezoidal structure, the height of which is equal to the height of the horizontal runner, and the angle between the bottom edge and the waist of the in-mold inoculation structure is 35-45°. Using the above structure, multiple inoculation blocks composed of inoculants can be placed in this specific trapezoidal in-mold inoculation structure, allowing the inoculant to achieve in-flow inoculation during the pouring process, thereby improving the efficiency of instantaneous in-mold inoculation.

[0012] Furthermore, two of each of the first gating system, second gating system, and foam filter are provided, and a filtration structure is formed by one first gating system, one second gating system, and one foam filter between them. The filtration structure is located on the left and right sides of the sprue. With this structure, the molten iron entering the runner from the sprue can smoothly form two streams entering the corresponding filtration structures on the left and right sides. This allows the pouring medium, or molten iron, coming out of the runner, not to directly enter the casting cavity, but to first enter the first gating system, where it is blocked and filtered by the foam filter, slowing down the flow rate of the molten iron. The molten iron between the first gating system and the sprue can be collected, buffered, and inoculated, and then enter the casting cavity more smoothly, improving the purity, refinement, and graphite spheroid count of the molten iron, thereby reducing shrinkage porosity and inclusion defects in the casting.

[0013] Furthermore, the end of the horizontal runner is connected to the first runner. With this structure, the molten iron first enters the first runner located at the top, then passes through the foam filter below for blocking, buffering and filtration, then enters the second runner, and then enters the casting cavity through the ingate. This can effectively purify impurities and slag in the molten iron and further reduce casting defects in the casting.

[0014] Furthermore, the ingate is provided with eight inlets, and four inlets are connected to the corresponding filter structure on the side. The tail end of the inlet is connected to the bottom of the casting cavity. With this structure, molten iron can be introduced through multiple inlets and enter the cavity from the bottom, ensuring the uniformity and stability of the molten iron entering the cavity.

[0015] Furthermore, the total cross-section of the eight ingates is smaller than the cross-section of the gating system. This structure allows the molten iron in the gating system to be fully filled, resulting in a purer and more stable flow of molten iron into the mold cavity, thereby reducing casting defects.

[0016] Furthermore, the cross-sectional area ratio of each component in the casting system is as follows: F (straight sprue) = 1 ceramic tube with an inner diameter of Φ100mm, F 直浇道 =One Φ100mm inner diameter ceramic tube, F horizontal runner = 60mm / 70mm, height 80mm, F 内浇道 =Eight ceramic tubes with an inner diameter of Φ40mm, ΣA 直浇道 ∶ΣA 横浇道 ∶ΣA 内浇道 = 1∶1.30∶1.28, therefore, it is only necessary to calculate the minimum cross-sectional area ΣA to determine the cross-sectional areas of the other components.

[0017] Furthermore, the foam filter is a silicon carbide foam filter, which is resistant to high temperatures and has a good filtration effect.

[0018] Furthermore, a safety riser is provided on the upper surface of the casting cavity, and the safety riser is located at the highest position on the top surface of the casting cavity; a flat vent is also provided on the upper surface of the casting cavity; with this structure, the casting can be fed to prevent defects caused by shrinkage. In addition, air bubbles and slag in the molten iron can be drawn out from the safety riser and the flat vent, further reducing casting defects. Attached Figure Description

[0019] Figure 1 This application presents a structural schematic diagram of the first view of a thick-section, high-pressure ductile iron template (casting or casting cavity).

[0020] Figure 2 This application presents a structural schematic diagram of the second view of a thick-section, high-pressure ductile iron template (casting or casting cavity).

[0021] As shown in the attached diagram: a. Body, a1. Cylinder hole, a2. Through hole.

[0022] Figure 3 This application presents a structural schematic diagram of the first view of the gating system.

[0023] Figure 4 This application presents a structural schematic diagram of the second view of the gating system.

[0024] Figure 5 This application presents a structural schematic diagram of the main view of the gating system.

[0025] Figure 6 This application presents a schematic diagram of the combination of the horizontal sprue and the in-mold inoculation structure within the gating system.

[0026] Figure 7 This application presents a schematic diagram of the main view of the combination of the horizontal sprue and the in-mold inoculation structure within the gating system.

[0027] Figure 8 This application presents a side view of the combined horizontal sprue and in-mold inoculation structure within the gating system.

[0028] Figure 9 This application presents a structural schematic diagram of the first view of the cast-in-place structure.

[0029] Figure 10 This application presents a structural schematic diagram of the second view of the cast-in-place structure.

[0030] As shown in the attached diagram: S1. Gating system, S2. Casting cavity, S3. Filtering structure, 1. Sprue, 2. Runner, 3. In-mold inoculation structure, 4. First runner, 5. Foam filter, 6. Second runner, 7. Ingate, 8. Safety riser, 9. Flat vent. Detailed Implementation

[0031] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are merely preferred embodiments, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this invention.

[0032] Furthermore, it should be noted that when a component is referred to as being "fixed to" another component, it can be directly on the other component or it may be fixed via another intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or it may be fixed via another intermediate component. When a component is considered to be "set on" another component, it can be set directly on the other component or it may be fixed via another intermediate component. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] The castings and casting cavities mentioned in this application have basically the same structure. During the pouring process, molten iron enters the casting cavity and finally cools and solidifies to form the casting. Therefore, the description of the corresponding position of the casting is equivalent to the description of the corresponding position of the casting cavity.

[0034] As attached Figure 1-10 The diagram illustrates an in-mold inoculation casting structure according to this application. The structure includes a gating system S1 and a casting cavity S2 connected thereto. The gating system S1 includes a sprue 1, a runner 2, an in-mold inoculation structure 3, a first gating 4, a foam filter 5, a second gating 6, and an ingate 7. The sprue 1 is located in the middle of the runner 2 and is perpendicularly connected to it (specifically, the sprue is vertically arranged, its lower end is perpendicularly connected to the upper surface of the runner, and the connection point is located at the midpoint of the runner's length). The in-mold inoculation structure 3 and... The horizontal runner 2 is connected, and the first runner 4 and the second runner 6 are stacked vertically along the axial direction of the straight runner 1 (the first runner is located on top and the second runner is located on the bottom). The foam filter 5 is located between the first runner 4 and the second runner 6 (that is, the first runner and the second runner are respectively set on the upper and lower sides of the foam filter in the thickness direction). The first runner 4, the second runner 6 and the foam filter 5 are connected to the tail end of the horizontal runner 2. One end of the inner runner 7 is horizontally connected to the second runner 6, and the other end is connected to the casting cavity S2.

[0035] By adopting the above structure, this application achieves instantaneous in-mold inoculation during the casting process by directly setting the in-mold inoculation structure on the gating system. Therefore, instantaneous in-mold inoculation can be achieved during the casting process of the thick-section ductile iron in this application. Based on this in-mold inoculation, the inoculant can be directly placed into the mold in block form (e.g., several blocks of inoculant weighing 0.3-0.5 kg each are placed in the in-mold inoculation structure of this application; the amount of inoculant added is 0.02-0.05% of the original molten iron mass; the inoculant is a silicon-barium inoculant with an elemental mass percentage of Si 69%-74%, Ca 0.5%-2.0%, Ba...). The composition of the inoculant (1.5%–2.5%, Al 2%–2.5%, S ≤ 0.02%, balance iron) can maximize the inoculation effect, reduce the amount of alloy used, and allow for the addition of different quantities and types of inoculants into the mold as needed, producing castings with different inoculation requirements using the same molten iron, thus overcoming the defects caused by traditional multiple inoculation. Moreover, the gating system set in this application has a high degree of matching with the mold of the thick-section ductile iron of this application, which can make the pouring more stable and reduce casting defects.

[0036] As attached Figure 3-4 , Figure 5 and Figure 9-10 As shown, the in-mold inoculation structure 3 described in this application is provided in at least two parts, and the two parts of the in-mold inoculation structure 3 are symmetrically arranged on the runner 2 with the sprue 1 as the center; specifically, the two parts of the in-mold inoculation structure 3 are arranged on the runners 2 on the left and right sides of the sprue 1, and are located below the runners, that is, in the opposite direction to the sprue; with this structure, when the molten iron enters the runner from the sprue, it is divided into the left and right sides, so that the in-mold inoculation structures on both sides can play a role, and instantaneous in-mold inoculation can be achieved in a more balanced manner.

[0037] As attached Figure 3-4 , Figure 5-8 ,and Figure 9-10 As shown, the intramorphic inoculation structure 3 described in this application is a trapezoidal structure, and the height of the intramorphic inoculation structure 3 ( Figure 7 H2 as shown) and the height of the horizontal runner 1 ( Figure 7 The angle between the bottom edge and the waist of the ingrown structure 3 shown in the figure is 35° to 45°. Figure 7 As shown in A); using the above structure, multiple inoculant blocks can be placed in this specific trapezoidal in-mold inoculation structure, so that the inoculant can achieve in-flow inoculation during the casting process, thereby improving the efficiency of instantaneous in-mold inoculation; the in-mold inoculation structure 3 of this application is a trapezoidal frame structure, which is formed below the horizontal gating by core sand molding, and the inoculant blocks can be directly pre-embedded in this in-mold inoculation structure made of molding sand.

[0038] As attached Figure 3-4 , Figure 5 and Figure 9-10 As shown, the first gating system 4, the second gating system 6, and the foam filter 5 described in this application are all provided in pairs. A set of filtering structures S3 is formed by one first gating system 4, one second gating system 6, and one foam filter 5 between them. The filtering structures S3 are distributed on the left and right sides of the sprue 1, with the sprue 1 as the center. That is, the two sets of filtering structures in this application are symmetrically distributed at both ends of the sprue. Using this structure, the molten iron entering the sprue from the sprue can smoothly form two streams entering the corresponding filtering structures on the left and right sides. This allows the pouring medium, or molten iron, exiting the sprue to not directly enter the casting cavity, but first enter the first gating system, and then be blocked and filtered by the foam filter, slowing down the flow rate of the molten iron. Furthermore, the molten iron between the first gating system and the sprue can be collected, buffered, and inoculated, and then enter the casting cavity more smoothly, improving the purity, refinement, and graphite spheroid count of the molten iron, thereby reducing shrinkage porosity and inclusion defects in the casting.

[0039] As attached Figure 3-4 As shown, the end of the horizontal runner 2 described in this application is connected to the first runner 4, that is, the horizontal runner 2 and the first runner 4 are directly connected. With this structure, the molten iron first enters the first runner located at the top, then passes through the foam filter below for blocking, buffering and filtration, then enters the second runner, and then enters the casting cavity through the ingate. This can effectively purify impurities and slag in the molten iron and further reduce casting defects in the casting.

[0040] As attached Figure 3-4 and Figure 10 As shown, the ingate 7 described in this application has eight ingates, and four in a group are connected to the corresponding filter structure S3. The tail end of the ingate 7 is connected to the bottom of the casting cavity S2 (the feed end of the sprue is the upper or top surface, and the opposite side is the lower or bottom surface). Specifically, the four ingates in each group have different lengths and are distributed in a way that gradually expands from the second sprue to the bottom of the casting cavity. With this structure, molten iron can be introduced through multiple ingates and multiple angle directions and enter the cavity from the bottom, ensuring the balance and stability of the molten iron entering the cavity.

[0041] As an example, the total cross-section of the eight ingates 7 described in this application is smaller than the cross-section of the gating 2. With this structure, the molten iron in the gating can be kept full, and the molten iron flowing into the mold cavity is purer and more stable, thereby reducing casting defects in the casting.

[0042] As an example, see attached Figure 5-8As shown, the cross-section of the horizontal gating system 2 in this application is trapezoidal, and the cross-section of the in-mold inoculation structure 3 is also trapezoidal; and as shown in the attached... Figure 8 As shown, the cross-section of the horizontal sprue 2 described in this application can be the same as the cross-sectional size of the in-mold inoculation structure 3 described in this application; the cross-sectional area ratio of each component in the gating system S1 described in this application is as follows: F (sprue) = one ceramic tube with an inner diameter of Φ100mm, F (sprue) = 60mm (top bottom) / 70mm (bottom bottom) and 80mm high molding sand casting mold, F (ingate) = eight ceramic tubes with an inner diameter of Φ40mm, ΣA sprue : ΣA horizontal sprue : ΣA ingate = 1 : 1.30 : 1.28, therefore, only the minimum cross-sectional area ΣA ingate needs to be calculated to determine the cross-sectional area of ​​the remaining components.

[0043] As an example, the foam filter 5 described in this application is a commercially available high-temperature resistant silicon carbide foam filter (silicon carbide foam ceramic filter), which is resistant to high temperatures and has good filtration effect.

[0044] As attached Figure 9-10 As shown, a safety riser 8 is also provided on the upper surface of the casting cavity S2 described in this application. The safety riser 8 is located at the highest position on the top surface of the casting cavity S2. Specifically, in this example, eight safety risers can be provided, located at the highest positions near the two ends of the casting cavity. In addition, a flat vent 9 is also provided on the upper surface of the casting cavity S2. Specifically, eight flat vents 9 are also provided, located at the center position on the top surface of the casting cavity and on the top surface of the two vertical extension walls at one end. With this structure, the casting can be fed to prevent defects caused by shrinkage. In addition, air bubbles and slag in the molten iron can be drawn out from the positions of the safety riser and the flat vent, further reducing casting defects.

[0045] This application provides a casting structure for in-mold inoculation, which incorporates an in-mold inoculation structure and a filtration structure. The in-mold inoculation structure enables instantaneous in-mold inoculation in a single operation. The in-mold inoculation structure is trapezoidal, with its height equal to the height of the runner, and an angle A of 35-45°. Several block-shaped inoculation blocks, each weighing 0.3-0.5 kg, are placed within the trapezoidal structure. When the molten iron enters the runner, it can be inoculated alongside the inoculant. Combined with this casting system, it ensures high fluidity, high filling capacity, and temperature uniformity of the molten iron, guaranteeing uniform temperature during casting and preventing defects caused by excessive temperature differences. It also effectively controls the pouring speed to maintain a steady flow of molten iron, avoiding defects caused by excessively fast or slow pouring speeds.

Claims

1. A casting structure for in-mold inoculation, comprising a gating system and a casting cavity communicating therewith; characterized in that: The gating system includes a sprue, a runner, an in-mold inoculation structure, a first gating, a foam filter, a second gating, and an ingate. The sprue is located in the middle of the runner and is perpendicularly connected to it. The in-mold inoculation structure is connected to the runner. The first and second gatings are stacked vertically along the axial direction of the sprue. The foam filter is located between the first and second gatings. The first, second, and foam filters are connected to the tail end of the runner. One end of the ingate is laterally connected to the second gating, and the other end is connected to the casting cavity.

2. The in-mold inoculation casting structure according to claim 1, characterized in that: The in-mold inoculation structure is provided in at least two parts, and the two parts of the in-mold inoculation structure are symmetrically arranged on the horizontal runner with the sprue as the center.

3. The in-mold inoculation casting structure according to claim 2, characterized in that: The in-mold inoculation structure is a trapezoidal structure, the height of the in-mold inoculation structure is equal to the height of the horizontal runner, and the angle between the bottom edge and the waist of the in-mold inoculation structure is 35-45°.

4. The in-mold inoculation casting structure according to claim 1, characterized in that: The first gating channel, the second gating channel, and the foam filter are all provided in twos, and a filter structure is formed by one first gating channel, one second gating channel, and one foam filter between them. The filter structure is located on the left and right sides of the gating channel with the gating channel as the center.

5. The in-mold inoculation casting structure according to claim 4, characterized in that: The end of the horizontal runner is connected to the first runner.

6. The in-mold inoculation casting structure according to claim 4, characterized in that: The ingate is provided with eight channels, and four channels are connected to the corresponding filter structure in a group. The tail end of the ingate is connected to the bottom of the casting cavity.

7. The in-mold inoculation casting structure according to claim 6, characterized in that: The total cross-section of the eight ingates is smaller than that of the gating system. This structure allows the molten iron in the gating system to be fully filled, resulting in a purer and more stable flow of molten iron into the mold cavity, thereby reducing casting defects.

8. The in-mold inoculation casting structure according to claim 1, characterized in that: The cross-sectional area ratio of each component in the casting system is: F 直浇道 =One Φ100mm inner diameter ceramic tube, F 横浇道 =60mm / 70mm, height 80mm, F 内浇道 =Eight ceramic tubes with an inner diameter of Φ40mm, ΣA 直浇道 ∶ΣA 横浇道 ∶ΣA 内浇道 = 1:1.30:1.

28.

9. The in-mold inoculation casting structure according to claim 1, characterized in that: The foam filter mentioned is a silicon carbide foam filter.

10. The in-mold inoculation casting structure according to claim 1, characterized in that: A safety riser is also provided on the upper surface of the casting cavity, and the safety riser is located at the highest position on the top surface of the casting cavity; a flat vent is also provided on the upper surface of the casting cavity.

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