A casting sand box and a casting method

Abstract

This invention relates to a casting sand box, comprising a lower box, a middle box, an upper box, and a pressure box component arranged sequentially from bottom to top. A partition is provided inside the middle box, dividing it into a first box and a second box. A suspended sand mold is disposed inside the second box. Several support structures for suspending the suspended sand mold are provided on the side of the partition facing the second box. A support rod is provided inside the upper box, supported between the support structures and the pressure box component. This invention also discloses a casting method using the aforementioned casting sand box. The casting sand box disclosed in this invention has an ingenious structural design, reducing the weight of the suspended sand mold while enhancing the sand-holding capacity of the middle box. The support structures, support rods, and pressure box component work together, with the support rods directly transferring the pressure force of the pressure box component to the suspended sand mold to counteract the buoyancy of the molten metal, preventing defects such as dimensional deviations, shrinkage porosity, and sand inclusions in the casting caused by mold displacement during pouring.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and in particular to a casting sand box and a casting method. Background Technology

[0002] For large fan-ring structure castings with L-shaped cross-sections, such as large offshore wind turbine rotor castings, the large size of the casting makes template molding costly and prone to deformation. Therefore, template-less molding is often used for production. To ensure material consistency, the pouring direction is generally chosen with the fan-ring structure facing downwards, and the upper side of the fan-ring structure serving as the parting surface. Furthermore, considering factory crane lifting capacity, ease of molding, core setting, coating operations, and safety, the parting process typically employs an upper mold + lower mold + one or more intermediate molds, resulting in a large cantilevered sand mold overall.

[0003] During the molding process, the lower sand mold is first created on the molding platform using a lower box. Then, the box is flipped over to sequentially pour sand to complete the molding of the middle and upper sand molds. When removing the mold, the upper sand mold is removed first, followed by the middle mold. However, when removing the middle mold, due to the very large weight and off-center center of gravity of the cantilevered sand mold, separation of the mold and the mold is difficult. This can easily cause damage to the cantilevered sand mold between the middle sand box and the mold during the removal process.

[0004] During the casting process, the cantilevered sand mold will bear enormous buoyancy force from the molten metal. Once the cantilevered sand mold shifts, it will cause a series of defects such as dimensional deviations, shrinkage porosity, and sand inclusions in the casting, which is extremely detrimental to product quality control. Currently, a method is used to press the middle ring sand mold by setting a pressure box on the top of the upper box and fixing the upper box and the middle ring sand box along the box opening plate. However, because the sand box has a large length span, it is prone to bending and deformation due to buoyancy, and there is a certain gap at the parting surface. The cantilevered sand mold still has the problem of lifting the box. There is currently no device or method to overcome the above defects. Summary of the Invention

[0005] Therefore, it is necessary to provide a casting sand box and casting method that can effectively press the cantilever hanger into place, addressing the aforementioned technical problems.

[0006] To solve the above problems, the present invention adopts the following technical solution:

[0007] This invention discloses a casting sand box, comprising a lower box, a middle box, an upper box, and a pressing box component arranged sequentially from bottom to top; a partition is provided inside the middle box, dividing the middle box into a first box and a second box, and a suspended sand mold is provided inside the second box; a plurality of support structures for suspending the suspended sand mold are provided on the side of the partition facing the second box; a support rod is provided inside the upper box, and the support rod is supported between the support structure and the pressing box component.

[0008] In one embodiment, the support structure includes a connecting rib, a sand-hanging plate, and a support member. A connecting rib is fixed to both the upper and lower parts of the sand-hanging plate. One end of the connecting rib facing away from the sand-hanging plate is fixed to the partition. The support member is disposed on the top of the connecting rib.

[0009] In one embodiment, the support member is a T-shaped structure with a support plate at its top. The support plate is perpendicular to the sand-hanging plate, and the support rod abuts against the support plate.

[0010] In one embodiment, the sand-hanging plate is provided with several through holes for connecting sand-hanging components.

[0011] In one embodiment, the projection of the connecting rib on the partition is a cross shape.

[0012] In one embodiment, the width of the support structure is 1 / 2 to 2 / 3 of the thickness of the suspended mold.

[0013] In one embodiment, a support channel is provided inside the upper box, and the support rod is disposed inside the support channel and is clearance-fitted with the support channel.

[0014] In one embodiment, a wedge block is wedged between the support rod and the pressure box member.

[0015] Secondly, embodiments of the present invention also disclose a casting method using any of the casting sand boxes described above, comprising the following steps:

[0016] The lower box, the middle box, and the upper box are respectively designed;

[0017] The lower box, the middle box, and the upper box are closed in sequence, and the support rod is placed on top of the support structure; the pressing component is pressed on top of the upper box, so that the support rod is supported between the pressing component and the support structure.

[0018] Furthermore, in the molding step, a molding tube is pre-placed in the upper box, and after sand is filled and molded, a support channel corresponding to the position of the support structure is formed; in the closing step, the support rod is placed in the support channel.

[0019] The technical solution adopted in this invention can achieve the following beneficial effects:

[0020] The casting sand box disclosed in this invention divides the middle box into a first box and a second box, reducing the sand-to-iron ratio and effectively reducing the weight of the suspended sand mold. The supporting structure enhances the middle box's ability to hold sand in the suspended sand mold, preventing damage and detachment during mold lifting, and reducing the rework and scrap rates of the suspended sand mold. At the same time, the supporting structure, in conjunction with the supporting rod and the pressure box components, forms a floating pressure box, reliably limiting the position of the suspended sand mold to counteract the buoyancy of the molten metal and avoid defects such as dimensional deviations, shrinkage porosity, and sand inclusions in the casting caused by the displacement of the suspended sand mold during the pouring process. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the middle box structure of the casting sand box disclosed in an embodiment of the present invention;

[0022] Figure 2 This is a structural diagram of the middle box after the design was completed;

[0023] Figure 3 A structural diagram of the supporting structure;

[0024] Figure 4 This is a cross-sectional view of the casting sand box disclosed in the embodiment of the present invention after the box is assembled;

[0025] Figure 5 for Figure 4 A magnified view of part A;

[0026] Explanation of reference numerals in the attached figures:

[0027] 100 - Lower box, 110 - Lower sand mold

[0028] 200-Middle box, 210-Suspended sand mold, 220-Sand core, 230-Cavity, 240-Support structure, 241-Connecting rib, 242-Sand hanging plate, 243-Support plate, 250-Partition plate, 251-First box, 252-Second box, 260-Support rod, 270-Wedge block, 280-Cavity;

[0029] 300-upper box, 310-upper sand mold;

[0030] 400 - Pressure box component. Detailed Implementation

[0031] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0032] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "top," "bottom," "end," "top," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0033] 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.

[0034] This invention discloses a sand box for casting, such as... Figures 1 to 5 As shown, the disclosed casting sand box includes a lower box 100, a middle box 200, an upper box 300, and a pressing piece 400. The lower box 100, middle box 200, and upper box 300 can be molded sequentially. After molding and casting, a lower sand mold 110 is formed in the lower box 100, a suspended sand mold 210 is formed in the middle box 200, and an upper sand mold 310 is formed in the upper box 300. The lower box 100, middle box 200, and upper box 300 are closed sequentially from bottom to top. The lower sand mold 110, suspended sand mold 210, and upper sand mold 310 together form a cavity 230 to contain molten metal. The pressing piece 400 presses down on the top of the upper box 300 to prevent the box from lifting during the pouring process.

[0035] Furthermore, after the middle box 200 is shaped and molded, a cavity 280 is formed within the suspended sand mold 210. During the box assembly process, a sand core 220 can be inserted into the cavity 280; or a sand core 220 can be inserted between the various sand molds. The lower sand mold 110, sand core 220, suspended sand mold 210, and upper sand mold 310 together form a cavity 230 to contain the molten metal.

[0036] A partition 250 can be installed inside the middle box 200, dividing the middle box 200 into a first box 251 and a second box 252. A hanging mold 210 is formed within the second box 252. To improve the strength of the partition 250 and balance the weight difference between the first box 251 and the second box 252, several reinforcing ribs can be staggered inside the first box 251. Several support structures 240 can also be installed on the side of the partition 250 facing the second box 252. Support rods 260 corresponding to the support structures 240 can also be installed inside the upper box 300, with the support rods 260 supported between the support structures 240 and the pressure box component 400. On the one hand, the support structure 240 acts as a sand hanger, improving the suspension capacity of the middle box 200 on the suspended sand mold 210; on the other hand, the support rod 260, together with the pressure box component 400, forms a floating pressure box, which reliably limits the support structure 240 and the suspended sand mold 210 connected to it, so as to prevent the suspended sand mold 210 from shifting due to lifting of the box and deformation of the sand box.

[0037] In the embodiments disclosed in this invention, the support structure 240 may include a connecting rib 241, a support member, and a sand hanging plate 242. The sand hanging plate 242 may be arranged parallel to the partition 250, and its upper and lower parts are each fixed to the side of the partition 250 by a connecting rib 241. The support member is fixed to the top surface of the connecting rib 241 located at the upper part.

[0038] Specifically, the support member can be a T-shaped structure, including a support plate 243 at the top and a connecting part connecting the support plate 243 and the connecting rib 241. One end of the connecting part is fixed to the connecting rib 241, and the other end is fixed to the middle part of the bottom of the support plate 243. The projection of the connecting rib 241 on the partition plate 250 can be a cross shape, ensuring connection strength while reducing its weight. The width of the sand-hanging plate 242 is generally 200mm to 300mm. Several circular through holes with a diameter of 30mm to 50mm are symmetrically arranged on the sand-hanging plate 242. During molding, reinforcing steel pipes, steel S-hooks, and other sand-hanging components are inserted into the holes to enhance the sand-hanging effect, thereby strengthening the middle box mold as a whole, so that the hanging mold 210, the partition plate 250, and the middle box 200 become a sufficiently strong whole.

[0039] It should be noted that the support plate 243 is set at the end of the connecting rib 241 near the hanging sand plate 242 and is perpendicular to the hanging sand plate 242. The top surface of the support plate 243 serves as its working surface. It is square and the side length can generally be 200mm to 300mm. After molding, the top surface of the support plate 243 exposes the hanging sand mold 210. Under the action of the pressure box component 400, the bottom of the support rod 260 presses against the exposed top surface of the support plate 243 to form a floating pressure box, which reliably limits the hanging sand mold 210.

[0040] Furthermore, the width of the support structure 240 can be 1 / 2 to 2 / 3 of the thickness of the suspended sand mold 210. It should be noted that the width of the support structure 240 is the distance between the side of the hanging sand plate 242 away from the partition plate 250, and the thickness of the suspended sand mold 210 is the distance between the cavity wall of the cavity 280 of the suspended sand mold 210 near the partition plate 250 and the partition plate 250.

[0041] In the embodiments disclosed in this invention, a support channel is provided inside the upper sand mold 310, and a support rod 260 is disposed within the support channel and has a clearance fit with the support channel. Specifically, when the upper box 300 is molded, a ceramic tube is pre-installed at a corresponding position in the upper box 300, which forms the support channel after molding. The cross-sectional diameter of the support channel is generally 80mm to 100mm. In addition, after the support rod 260 is placed in the support channel, one end of it is attached to the support plate 243, and the other end has a certain gap with the pressure box component 400. At this time, a wedge block 270 is wedged into this gap and secured. The wedge block 270 is preferably a triangular wedge block.

[0042] Secondly, embodiments of the present invention disclose a casting method using any of the casting sand boxes described above, which may specifically include the following steps:

[0043] S1. Shape the lower sand mold 110 in the lower box 100;

[0044] S2. Shape the mold in the second box 252 to form a hanging mold sand mold 210;

[0045] S3. Place the ceramic tube in the designed position inside the upper box 300. The bottom end of the ceramic tube can be placed in the middle of the top surface of the support plate 243, and the top end of the ceramic tube can be positioned and limited by the box strap of the upper box 300. After filling with sand, an upper sand mold 310 with a support channel is formed.

[0046] S4, lower box 100, middle box 200 and upper box 300 are assembled in sequence. After the upper sand mold 310 is assembled, the support rod 260 is placed in the support channel. At this time, the bottom end of the support rod 260 is located on the support plate 243, and the top end can be slightly higher than the upper box 300.

[0047] S5. Press the pressure box component 400 onto the upper box 300. The weight of the pressure box component 400 can be 3 to 5 times the weight of the casting. The pressure box component 400 is pressed onto the top of the support rod 260. During the casting process, the molten metal generates buoyancy on the suspended sand mold 210. This buoyancy is transmitted to the support rod 260 through the suspended sand mold 210 and is reliably limited by the pressure box component 400, effectively preventing the suspended sand mold 210 from partially or completely floating and shifting.

[0048] Furthermore, in step S2, before the middle box 200 is shaped, steel pipes, steel S-hooks and other components can be hung in the round holes of the sand hanging plate 242 to optimize the sand hanging effect of the middle box 200 and to strengthen the hanging mold 210 as a whole, so that it is tightly connected with the middle box 200 as a whole.

[0049] Furthermore, in step S5, after pressing the pressure box 400 onto the upper box 300, the top of the support rod 260 is higher than the upper box 300 and lower than the pressure box 400. There is a gap between the pressure box 400 and the support rod 260, which can be wedged in by inserting the wedge block 270.

[0050] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A casting sand box, comprising a lower box, a middle box, an upper box, and a pressure box component arranged sequentially from bottom to top, characterized in that, The middle box is provided with a partition, which divides the middle box into a first box and a second box. The second box contains a suspended sand mold. The partition is provided with a number of support structures for suspending the suspended sand mold on the side facing the second box. The upper box is provided with a support rod, which is supported between the support structure and the pressure box component; The support structure includes a connecting rib, a sand-hanging plate, and a support member. A connecting rib is fixed to both the upper and lower parts of the sand-hanging plate. The end of the connecting rib facing away from the sand-hanging plate is fixed to the partition. The support member is disposed on the top of the connecting rib. The support member has a T-shaped structure, and the top of the support member is a support plate. The support plate is perpendicular to the sand hanging plate, and the support rod abuts against the support plate. The upper box is provided with a support channel, and the support rod is disposed in the support channel and is clearance-fitted with the support channel.

2. The casting sand box according to claim 1, characterized in that, The sand-hanging plate is provided with several through holes for connecting sand-hanging components.

3. The casting sand box according to claim 1, characterized in that, The projection of the connecting rib on the partition plate is a cross shape.

4. The casting sand box according to claim 1, characterized in that, The width of the support structure is 1 / 2 to 2 / 3 of the thickness of the suspended mold.

5. The casting sand box according to claim 1, characterized in that, A wedge block is wedged between the support rod and the pressure box component.

6. A casting method using a casting sand box as described in any one of claims 1-5, characterized in that, Includes the following steps: The lower box, the middle box, and the upper box are respectively designed; The lower box, the middle box, and the upper box are closed in sequence, and the support rod is placed on top of the support structure; the pressing component is pressed on top of the upper box, so that the support rod is supported between the pressing component and the support structure.

7. The casting method according to claim 6, characterized in that, In the molding step, a molding tube is pre-placed in the upper box, and after sand is filled and molded, a support channel corresponding to the position of the support structure is formed; in the box closing step, the support rod is placed in the support channel.

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