U-shaped variable cross-section pouring cup and gravity casting metal mold

Abstract

The invention discloses a U-shaped variable cross-section pouring cup and a gravity casting metal mold, the U-shaped variable cross-section pouring cup comprises an inlet area, a first arc-shaped descending area, an arc-shaped ascending area, a second arc-shaped descending area and a sprue which are communicated in sequence, and the pouring cup can improve the quality of a casting.

Description

Technical Field

[0001] The invention belongs to the technical field of casting mold structure design, and relates to a U-shaped variable-section pouring cup and a gravity casting metal mold. Background Art

[0002] The pouring system is the channel through which the liquid metal in the casting mold flows into the mold cavity. It is usually composed of units such as a pouring cup, a sprue, a sprue nest, a runner, and an ingode. The function of the pouring cup is to receive the molten metal from the ladle and introduce it into the sprue. The function of the sprue is to guide the molten metal in the pouring cup into the runner, establish a sufficient pressure head, and allow the molten metal to overcome the flow resistance under the action of gravity and fill the mold cavity in time. The pouring nest has a buffering effect on the molten metal from the straight pouring, shortens the turbulent zone at the corner of the straight-runner, and improves the pressure distribution in the runner. In addition to introducing the molten metal into the ingode, the main function of the runner is to skim slag. The traditional gravity metal mold casting pouring cup adopts a funnel shape, such as Figure 1 As shown. The disadvantage of the traditional pouring cup is that the pouring process is easily interfered by human factors. Different skill levels and operating habits of the pourers, and even different working conditions of the same pourer will lead to unstable aluminum liquid filling flow field when pouring the same casting, which in turn causes fluctuations in casting quality. The shells used in aircraft engine fuel accessories are mostly aluminum alloy parts, most of which are cast, and the design has high requirements for the internal quality of the parts, especially gas and slag hole defects. Aircraft engine castings have strict requirements on the number and size of such casting defects. If they exceed the range, repair welding is not allowed and they are directly scrapped. Therefore, producing high-quality castings with fewer or even no gas and slag hole defects in the internal structure has become a technical difficulty that needs to be solved urgently. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a U-shaped variable-section pouring cup and a gravity casting metal mold, wherein the pouring cup can improve the quality of the casting.

[0004] To achieve the above-mentioned purpose, the present invention discloses a U-shaped variable-section pouring cup, comprising an inlet area, a first arc-shaped descending area, an arc-shaped ascending area, a second arc-shaped descending area and a straight runner which are connected in sequence.

[0005] The further improvement of the U-shaped variable cross-section pouring cup of the present invention is:

[0006] Furthermore, the inlet area includes a cylindrical inlet gate and a transition area of ​​an inverted truncated cone structure, wherein the lower end of the inlet gate is connected to the upper end of the transition area, and the lower end of the transition area is connected to the first arc-shaped descending area.

[0007] Furthermore, the diameter of the inlet gate is greater than ΦM, the height of the inlet gate is greater than or equal to 50 mm, the diameter of the upper end surface of the transition zone is ΦM, and the diameter of the lower end surface of the transition zone is 2.2Φ 直 -2.5Φ 直 , the height of the transition zone is H M , the slope of the side wall of the transition zone is 5°-8°.

[0008] Furthermore, the first arc-shaped descending area is a 1 / 4 annular pipe.

[0009] Furthermore, the diameter of the first arc-shaped descending area is 2Φ 直 -2.3Φ 直 .

[0010] Furthermore, the axis of the arc-shaped rising area meets y=10sin15x, 0<x<π.

[0011] Furthermore, the diameter of the end of the arc-shaped rising area connected to the first arc-shaped descending area is 2Φ 直 -2.3Φ 直 , the diameter of the other end of the arc rising area is 1.2Φ 直 -1.5Φ 直 .

[0012] Furthermore, along the flow direction of the filtrate, the diameter of the arc-shaped rising area gradually decreases.

[0013] Furthermore, the second arc-shaped descending area has a radius of 4Φ 直 The diameter of the cross section of the second arc-shaped descending area is 1.2 Φ 直 -1.5Φ 直 .

[0014] The invention discloses a gravity casting metal mold, comprising the U-shaped variable-section pouring cup.

[0015] The present invention has the following beneficial effects:

[0016] The U-shaped variable-section pouring cup and gravity casting metal mold described in the present invention include an inlet area, a first arc-shaped descending area, an arc-shaped rising area, a second arc-shaped descending area and a straight runner that are connected in sequence during specific operation. The molten aluminum enters the pouring cup from the ladle, which can ensure that when the molten aluminum flows from the pouring cup into the straight runner entrance, the flow field is stable when the molten aluminum enters the straight runner entrance from the end of the pouring cup, thereby minimizing the influence of human factors on the filling of the molten aluminum in the pouring system and the mold cavity during the pouring process, avoiding the generation of air entrainment and turbulence during the molten aluminum filling process, thereby reducing the probability of invasive pores and oxidation slag inclusion defects, and ultimately achieving the purpose of improving the quality of castings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 It is a structural diagram of the prior art;

[0019] Figure 2a It is a structural diagram of the pouring cup in the present invention;

[0020] Figure 2b A top view of the pouring cup of the present invention;

[0021] Figure 3 This is a structural diagram of a traditional pouring cup metal mold;

[0022] Figure 4 It is a structural diagram of the gravity casting metal mold in the present invention;

[0023] Figure 5 This is a simulation diagram of the pouring cup of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0027] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0028] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0029] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0032] Embodiment 1

[0033] The U-shaped variable-section pouring cup of the present invention comprises an inlet area, a first arc-shaped descending area, an arc-shaped ascending area, a second arc-shaped descending area and a sprue which are connected in sequence;

[0034] The inlet area includes a cylindrical inlet gate and a transition area of ​​an inverted truncated cone structure, wherein the lower end of the inlet gate is connected to the upper end of the transition area, and the lower end of the transition area is connected to the first arc-shaped descending area. The diameter of the inlet gate is greater than ΦM, the height of the inlet gate is greater than or equal to 50mm, the diameter of the upper end surface of the transition area is ΦM, and the diameter of the lower end surface of the transition area is 2.2Φ 直 -2.5Φ 直 , the height of the transition zone is H M The slope of the side wall of the transition zone is 5°-8°, so that the transition zone can establish a sufficient pressure head, so that the aluminum liquid can overcome the flow resistance under the action of gravity and fill the high point of the arc rising zone and the second arc descending zone in time to prevent air entrainment. The purpose of designing a variable cross-section at the pouring line is to facilitate observation by the pouring worker. During the pouring process, after the aluminum liquid submerges the pouring line, until the pouring is completed, the aluminum liquid level must be above the pouring line.

[0035] The first arc-shaped descending area is a 1 / 4 annular pipe, and the diameter of the first arc-shaped descending area is 2Φ 直 -2.3Φ 直 The centerline contour of the first arc-shaped descending area is 4Φ in radius. 直 The first arc-shaped descending area is used to store the aluminum liquid from the inlet area. The first arc-shaped descending area and the arc-shaped ascending area form a U-shaped tube. After reaching a suitable liquid level, the aluminum liquid will flow into the second arc-shaped descending area. The advantage of the U-shaped tube is that as long as the aluminum liquid is always full, there will be no air entrainment.

[0036] Arc rising area: The axis of the arc rising area conforms to y=10sin15x (0<x<π). This trajectory design is to ensure the smooth flow of aluminum liquid filling the mold, so as not to cause aluminum liquid to splash around during filling and then roll up air. And the diameter of the end of the arc rising area connected to the first arc descending area is 2Φ 直 -2.3Φ 直 , the diameter of the other end of the arc rising area is 1.2Φ 直 -1.5Φ 直 Along the flow direction of the filtrate, the diameter of the arc-shaped rising zone gradually decreases, that is, a variable cross-section structure is adopted. The purposes of designing the variable cross-section are: 1) the aluminum liquid is in a pressurized flow state and is easy to fill the pouring system; 2) it can prevent the vertical vortex caused by the horizontal vortex and prevent bubbles from being brought into the straight runner; 3) reduce the pouring state of the pouring worker.

[0037] When working, the arc rising area and the first arc descending area together act as a "storage tank". When the aluminum liquid is stored to a certain amount, it will flow into the straight runner through the second arc descending area. It plays a certain buffering role on the aluminum liquid in the filling, slows down the flow speed of the aluminum liquid, and reduces the adverse effects of splashing and turbulence of the aluminum liquid.

[0038] The second arc-shaped descending area: The arc-shaped ascending area is connected to the sprue through the second arc-shaped descending area, which plays an intermediate transition role. The purpose of the second arc-shaped descending area is to introduce the aluminum liquid in the arc-shaped ascending area into the sprue. Avoid splashing during the aluminum liquid filling process, and then cause air entrainment and the resulting oxidation slag defects. Therefore, the radius of the second arc-shaped descending area is 4Φ 直 The 1 / 4 circular ring structure is located in the first quadrant. The common tangent line at the connection between the second arc-shaped descending area and the arc-shaped ascending area is a horizontal line. This design can ensure the smooth flow of aluminum liquid and avoid air entrainment. The diameter is designed to be 1.2Φ 直 -1.5Φ 直 The purpose is to allow the molten aluminum to quickly fill the sprue.

[0039] It should be noted that the present invention can ensure that when the aluminum liquid enters the straight runner inlet from the ladle, the flow field is stable when the aluminum liquid enters the straight runner inlet from the end of the pouring cup, thereby minimizing the influence of human factors on the filling of the aluminum liquid in the pouring system and the mold cavity during the pouring process, avoiding the generation of air entrainment and turbulence during the aluminum liquid filling process, thereby reducing the probability of invasive pores and oxidation slag inclusion defects, and ultimately achieving the purpose of improving the quality of castings.

[0040] Embodiment 2

[0041] The pouring cup of a gravity casting metal mold is usually connected to the mold by a countersunk screw, such as Figure 3 a. The inner cavity shape is Figure 3 b. When preparing for production, first remove the traditional pouring cup from the mold, and then install the new pouring cup with the countersunk screw. The installation position of the new pouring cup on the mold is based on the coincidence of its end center with the upper end center of the sprue. The mold appearance and inner cavity diagram after replacing the new pouring cup are shown in Figure 4 a and Figure 4 As shown in b.

[0042] After installation, use a dry ice cleaning machine to remove the old coating on the mold cavity and parting surface, preheat the cleaned mold to 200-300℃, and then spray the ZnO coating on the mold pouring system and the casting cavity for 2-3 times and evenly. Install the prepared mold on the two-opening gravity pouring machine. The pourer pours the aluminum liquid into the upper end of the new pouring cup through the ladle and then flows into the entire cavity. Finally, after the casting solidifies, the mold is opened to take out the casting, completing the entire pouring process.

[0043] Since the actual filling process of the aluminum liquid in the pouring cup and the runner cannot be directly observed, it can only be visualized and analyzed in the casting simulation software. From the filling simulation results of the Anycasting software, it can be seen that after using the present invention, the aluminum liquid at the front end is always mixed with air in the runner from the time of just filling the mold to the time of filling the mold to the pouring cup. Figure 5 As shown in a, b, and c, when the aluminum liquid at the front end is just filled into the casting cavity, the new pouring cup and the entire runner are quickly filled with aluminum liquid, and this full state is maintained until the entire filling process is completed. Figure 5 e, f, and g. This shows that the design of the present invention is very reasonable, so that the aluminum liquid can quickly fill the entire runner, avoiding the generation of invasive gas, thereby greatly reducing the probability of pores in the casting and improving the qualified rate of the casting. In addition, it can be seen from the speed simulation results that after the filtrate fills the new pouring cup, the filling speed of the filtrate at the end of the pouring cup is very low (shown in green), which can avoid the turbulence of the filtrate here, thereby reducing the occurrence of air entrainment.

[0044] In summary, the present invention can not only enable the aluminum liquid to quickly fill the entire flow channel, but also slow down the filling speed of the aluminum liquid, and ultimately greatly reduce the probability of porosity defects in the casting.

[0045] It should be noted that the quality of castings produced using traditional pouring cups fluctuates greatly, and the scrap rate due to internal gas slag holes is about 50% each year. The quality of castings produced using the present invention has been greatly improved, and the scrap rate due to internal gas slag holes is only about 10%. The production cost saved due to quality improvement is more than 200,000 yuan each year. At the same time, this design idea can also be extended to other castings, greatly improving the qualified rate of castings of the same type.

[0046] Embodiment 3

[0047] The gravity casting metal mold of the present invention comprises a U-shaped variable-section pouring cup, wherein the U-shaped variable-section pouring cup comprises an inlet area, a first arc-shaped descending area, an arc-shaped ascending area, a second arc-shaped descending area and a straight runner which are sequentially connected; the inlet area comprises a cylindrical inlet and a transition area of ​​an inverted truncated cone structure, wherein the lower end of the inlet is connected to the upper end of the transition area, and the lower end of the transition area is connected to the first arc-shaped descending area; the diameter of the inlet is greater than ΦM, the height of the inlet is greater than or equal to 50mm, the diameter of the upper end surface of the transition area is ΦM, and the diameter of the lower end surface of the transition area is 2.2Φ 直 -2.5Φ 直 , the height of the transition zone is H M The slope of the side wall of the transition zone is 5°-8°; the first arc-shaped descending zone is a 1 / 4 annular pipe; the diameter of the first arc-shaped descending zone is 2Φ 直 -2.3Φ 直; The axis of the arc rising area meets y=10sin15x, 0<x<π; The diameter of the end of the arc rising area connected to the first arc descending area is 2Φ 直 -2.3Φ 直 , the diameter of the other end of the arc rising area is 1.2Φ 直 -1.5Φ 直 ; Along the flow direction of the filtrate, the diameter of the arc rising area gradually decreases; the second arc descending area has a radius of 4Φ 直 The diameter of the cross section of the second arc-shaped descending area is 1.2 Φ 直 -1.5Φ 直 .

[0048] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0049] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0050] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A U-shaped variable cross-section pouring cup, characterized in that: It includes an inlet area, a first arc-shaped descending area, an arc-shaped ascending area, a second arc-shaped descending area and a straight runner which are connected in sequence.

2. The U-shaped variable cross-section pouring cup according to claim 1, characterized in that: The inlet area includes a cylindrical inlet gate and a transition area of ​​an inverted truncated cone structure, wherein the lower end of the inlet gate is connected to the upper end of the transition area, and the lower end of the transition area is connected to the first arc-shaped descending area.

3. The U-shaped variable cross-section pouring cup according to claim 2, characterized in that: The diameter of the inlet gate is greater than ΦM, the height of the inlet gate is greater than or equal to 50mm, the diameter of the upper end surface of the transition zone is ΦM, and the diameter of the lower end surface of the transition zone is 2.2Φ 直 -2.5Φ 直 , the height of the transition zone is H M , the slope of the side wall of the transition zone is 5°-8°.

4. The U-shaped variable cross-section pouring cup according to claim 1, characterized in that: The first arc-shaped descending area is a 1 / 4 annular pipe.

5. The U-shaped variable cross-section pouring cup according to claim 4, characterized in that: The diameter of the first arc-shaped descending area is 2Φ 直 -2.3Φ 直 .

6. The U-shaped variable cross-section pouring cup according to claim 1, characterized in that: The axis of the arc-shaped rising area conforms to y=10sin15x, 0<x<π.

7. The U-shaped variable cross-section pouring cup according to claim 6, characterized in that: The diameter of the end of the arc-shaped rising area connected to the first arc-shaped descending area is 2Φ 直 -2.3Φ 直 , the diameter of the other end of the arc rising area is 1.2Φ 直 -1.5Φ 直 .

8. The U-shaped variable cross-section pouring cup according to claim 7, characterized in that: Along the flow direction of the filtrate, the diameter of the arc-shaped rising area gradually decreases.

9. The U-shaped variable cross-section pouring cup according to claim 1, characterized in that: The second arc-shaped descending area has a radius of 4Φ 直 The diameter of the cross section of the second arc-shaped descending area is 1.2 Φ 直 -1.5Φ 直 .

10. A gravity casting metal mold, characterized in that: The invention comprises the U-shaped variable-section pouring cup as described in any one of claims 1 to 9.

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