One-mold multi-piece casting process method for large cylindrical castings

Abstract

The invention provides a one-mold multi-piece casting process method for large cylindrical castings, and belongs to the technical field of metal casting. Comprising the following steps: vertically stacking a plurality of cylindrical casting models with similar overall dimensions to form a casting group; a pit core assembly molding process is adopted, and sand cores are split according to the shape of a casting group; sand cores are sequentially assembled in a box distribution pit, and during assembly, a) adjacent casting cavities are connected through a fin type pouring gate; b) arranging a stepped pouring system, wherein the stepped pouring system comprises at least two ingates with different heights; c) pre-embedding a lock cylinder device in the bottom box to fix a pouring gate sand core; d) supporting from the inner side of the sand core by adopting a top core steel pipe; and pouring after the box is assembled by filling sand on the periphery. According to the invention, the cylindrical castings with similar overall dimensions are vertically stacked to achieve the purpose of simultaneously producing multiple castings by one mold, so that the sand-to-iron ratio is reduced, and the process yield is improved; by using the pit core assembly modeling process method, the use of tools is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal casting, and particularly relates to a one-mold multi-piece casting process method for large cylindrical castings. Background Art

[0002] Currently, most of the single-piece large-sized cylindrical castings are produced using the lost foam full-scale pattern molding process. The lost foam full-scale pattern molding requires making the foam full-scale pattern of the casting, the full-scale pattern of the gating system, the foam support full-scale pattern, etc. Refer to Figure 2 As shown, when molding, the ring box 2' needs to be molded first. After the resin sand in the ring box 2' is completely hardened, parting sand is sprinkled and the cover box 3' is molded. After the resin sand in the cover box 3' is completely hardened, the ring box 2' and the cover box 3' are turned over as a whole. After the foam support is taken out, parting sand is sprinkled and the bottom box 1' is molded. After the resin sand in the bottom box 1' is hardened, it is turned over as a whole and the box is opened. After all the foam full-scale patterns are taken out, the coating is applied. After the outer mold is prepared, the box is assembled and combined, melted and poured, and the box is knocked out and cleaned to obtain qualified castings.

[0003] There are still many defects in using the lost foam full-scale pattern molding process to produce single-piece large-sized cylindrical castings: 1. During production, three box openings for molding are required, and the sand box needs to be turned over twice. The molding process is complex and the production efficiency is low. 2. The sand-to-iron ratio is large and the process yield is low. Although the cost of making wooden molds in the traditional process is saved, the overall production cost is high. 3. At least 3 sand boxes are required for each casting produced, and the production of castings is restricted by the number of toolings. Therefore, it is urgent to develop a new casting process to overcome these defects. Summary of the Invention

[0004] The technical problem solved by the present invention: Provide a one-mold multi-piece casting process method for large cylindrical castings. The present invention simplifies the molding process, reduces the sand-to-iron ratio, improves the process yield, and reduces the use of production toolings, so as to achieve the purpose of reducing production costs and improving production efficiency.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A one-mold multi-piece casting process method for large cylindrical castings, comprising the following steps:

[0007] Vertically stack multiple cylindrical casting models with similar contour dimensions to form a casting group;

[0008] Adopt the pit core assembly molding process and split the sand cores according to the shape of the casting group;

[0009] Sequentially assemble the sand cores in the box-making pit. When assembling:

[0010] a) Connect adjacent casting cavities through a flash-type runner;

[0011] b) providing a stepped pouring system comprising at least two ingates at different heights;

[0012] c) Pre-embed the lock core device in the bottom box to fix the sprue sand core;

[0013] d) Use a top core steel pipe to support the sand core from the inside;

[0014] The outer sand filling is completed and then poured.

[0015] To further define the above scheme, the stepped pouring system includes: a low-positioned first ingrown gate and a high-positioned second ingrown gate, wherein the low-positioned first ingrown gate is connected to the bottom of the stacked castings; the high-positioned second ingrown gate is connected to the middle casting through an ingrown gate docking port with a trapezoidal cross-section.

[0016] Further limiting the above solution, the stepped pouring system further includes a riser, a pouring cup, a runner, and a sprue. When the box is assembled, a sprue is provided in the peripheral sand core and the bottom box. The runner is provided in the bottom box. A pouring cup is provided at the inlet of the sprue. The sprue is connected to the runner, the runner is connected to the first ingredient and the second ingredient, and the riser is connected to the casting cavity:

[0017] As a further limitation of the above solution, the lock core device includes a screw pre-buried in the bottom box and a locking nut that cooperates with the reserved channel of the runner sand core.

[0018] As a further limitation of the above solution, the top core steel pipe is arranged according to the number of the inner sand cores, and after the inner sand cores are supported by the top core steel pipe, the interior of the inner sand cores is not filled with sand or is filled with dry sand.

[0019] A further limitation of the above solution is that when packing, discarded oil drums and dry sand blocks are placed at appropriate positions during the sand filling process on the outside of the peripheral sand core.

[0020] The advantages of the present invention compared with the prior art are:

[0021] 1. This solution achieves the goal of producing multiple castings simultaneously in one mold by stacking cylindrical castings with similar outline dimensions vertically, reducing the sand-iron ratio and improving the process yield rate. The pit core molding process reduces the use of tooling and improves production efficiency.

[0022] 2. This solution reduces manual labor time, the use of raw materials and production tooling by designing a one-mold, multiple-piece casting process for large cylindrical castings, thereby achieving the goal of reducing production costs and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of a one-mold, multi-piece casting process for large cylindrical castings according to the present invention;

[0024] Figure 2 It is a schematic diagram of the lost foam pattern molding process in the prior art. Specific Embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] Please refer to Figure 1-2 for a detailed description of the embodiments of the present invention.

[0027] Embodiment: A casting process method for multiple parts of a large cylindrical casting in one mold, including the following steps:

[0028] Vertically stack multiple cylindrical casting models with similar contour dimensions to form a casting group. Refer to Figure 1 as shown. The casting group in this embodiment includes casting Ⅰ 14, casting Ⅱ 15, casting Ⅲ 16, casting Ⅳ 17, casting Ⅴ 18, and casting Ⅵ 19. The diameter dimension of the casting is restricted by the size of the molding pit. The number of castings in the casting group should not be too large to prevent insufficient pouring caused by reduced fluidity of the molten iron.

[0029] Adopt the ground pit core assembly molding process and split the sand cores according to the shape and size of the casting group;

[0030] Sequentially assemble the sand cores in the mating box pit. When assembling:

[0031] a) Connect adjacent casting cavities through a fillet-type runner 7;

[0032] b) Set a stepped gating system including at least two inner gates with different heights;

[0033] c) Embed a core locking device 20 in the bottom box 2 to fix the runner sand core;

[0034] d) Support from the inside of the sand core using a core lifting steel pipe 11. The material of the core lifting steel pipe is selected as 45 steel to ensure that the sand core does not displace during the molding and mating box process.

[0035] After filling the sand around to complete the mating box, pour the molten metal.

[0036] In this embodiment, large cylindrical castings with similar dimensions and shapes are stacked, and the castings are connected to each other using fillet-type inner gates, enabling multiple castings to be produced in one mold, reducing the use of tooling, and effectively improving production efficiency.

[0037] In a specific embodiment: The stepped gating system includes a low-position first ingate 3 and a high-position second ingate 4. The low-position first ingate 3 communicates with the bottom of the stacked castings. The high-position second ingate 4 communicates with the middle casting through an ingate docking port 6 with a trapezoidal cross-section.

[0038] The stepped gating system further includes a riser 9, a pouring cup 12, a runner 21, and a sprue 22. When assembling the mold boxes, the sprue 22 is arranged in the peripheral core and the bottom box 2. The runner 21 is arranged in the bottom box 2. A pouring cup 12 is provided at the inlet of the sprue 22. The sprue 22 communicates with the runner 21. The runner 21 communicates with the first ingate 3 and the second ingate 4. The riser 9 communicates with the casting cavity.

[0039] When using the stepped gating system, during the pouring process under the action of atmospheric pressure, the molten iron in the first ingate 3 first enters the cavity. When the molten iron rises to the position of casting III 16 through the lap joint type runner, the molten iron in the second ingate 4 enters the cavity. This is beneficial to the smooth filling of the molten metal and the realization of the sequential solidification of the casting, and avoids the generation of casting defects.

[0040] In this embodiment, an ingate docking port with a trapezoidal cross-section is added at the position of the second ingate 4 to prevent the displacement of the porcelain tube during the molding process of the bottom box and the 2# core, resulting in a reduction in the actual cross-sectional area of the ingate 2.

[0041] In a specific embodiment: The lock core device 20 includes a screw rod embedded in the bottom box 2 and a lock nut that cooperates with the reserved channel of the runner core.

[0042] In this embodiment, several lock core devices are embedded during the bottom box molding process, and lock core screw channels are reserved at the corresponding positions of the runner cores. During the mold box assembly process, the lock core devices are used to lock the runner core and the bottom box into one body to prevent the runner core from floating under the buoyancy of the molten iron.

[0043] In a specific embodiment: The core pushing steel pipes 11 are arranged according to the number of inner cores. After the inner cores are supported by the core pushing steel pipes 11, the inside thereof is not filled with sand or filled with dry sand 10. Among them Figure 1 The markings 1#, 2#, 3#, 4#, and 5# are all the core installation positions.

[0044] In this embodiment, during the mold box assembly process, the core pushing steel pipes are used to support the 2# core and the 3# core from the inside of the cores. This prevents the 2# core and the 3# core from moving inward under the action of the molten iron during the pouring process, resulting in an increase in the casting size. After the core pushing steel pipes are installed, the inside of the core can be not filled with sand or filled with dry sand, reducing the use of resin sand and lowering the production cost.

[0045] In a specific embodiment: During the sand filling process outside the peripheral core when assembling the mold boxes, waste oil drums 5 and dry sand blocks 8 are placed at appropriate positions.

[0046] In this embodiment, waste oil drums, dry sand blocks, etc. are placed at appropriate positions during the sand filling process outside the core on the periphery of the mold box, realizing the reuse of waste, reducing the use of resin sand, and lowering the production cost.

[0047] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claimed invention.

[0048] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A casting process method for multiple castings of the same type of large cylindrical castings, characterized in that: The following steps are involved: A plurality of cylindrical casting models with similar outline dimensions are stacked vertically to form a casting group; Adopt pit core molding technology to split the sand core according to the shape of the casting group; Assemble the sand cores in sequence in the distribution pit. During assembly: a) connecting adjacent casting cavities via a sprue (7); b) providing a stepped pouring system comprising at least two ingates at different heights; c) pre-embedding a lock core device (20) in the bottom box (2) to fix the runner sand core; d) using a top core steel pipe (11) to support the sand core from the inside; The outer sand filling is completed and then poured.

2. The one-mold multi-piece casting process method for large cylindrical castings according to claim 1, characterized in that: The stepped pouring system comprises: a first ingrown runner (3) at a low position and a second ingrown runner (4) at a high position, wherein the first ingrown runner (3) at a low position is connected to the bottom of the stacked castings; and the second ingrown runner (4) at a high position is connected to the middle casting via an ingrown runner docking port (6) with a trapezoidal cross section.

3. The one-mold multi-piece casting process method for large cylindrical castings according to claim 2, characterized in that: The stepped pouring system further comprises a riser (9), a pouring cup (12), a runner (21) and a sprue (22). When the boxes are assembled, the sprue (22) is arranged in the peripheral sand core and the bottom box (2). The runner (21) is arranged in the bottom box (2). A pouring cup (12) is provided at the inlet of the sprue (22). The sprue (22) is communicated with the runner (21). The runner (21) is communicated with the first ingrow (3) and the second ingrow (4). The riser (9) is communicated with the casting cavity.

4. The one-mold multi-piece casting process method for large cylindrical castings according to claim 1, characterized in that: The locking core device (20) comprises a screw pre-buried in the bottom box (2) and a locking nut matched with a reserved channel of the runner sand core.

5. The one-mold multi-piece casting process method for large cylindrical castings according to claim 1, characterized in that: The top core steel pipe (11) is arranged according to the number of inner sand cores. After the inner sand cores are supported by the top core steel pipe (11), the interiors of the inner sand cores are not filled with sand or are filled with dry sand (10).

6. The one-mold multi-piece casting process method for large cylindrical castings according to claim 1, characterized in that: When packing, waste oil barrels (5) and dry sand blocks (8) are placed at appropriate positions during the sand filling process outside the peripheral sand core.

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