Casting structure and method for improving box opening efficiency and obtained casting

Abstract

The invention discloses a casting structure and method for improving box opening efficiency and an obtained casting, and belongs to the field of cast iron metallurgy, the casting structure comprises a sand core area, a casting area and the casting area, at least one hoisting hole is formed in the casting area, a hoisting through part is fixedly installed at the hoisting hole, the hoisting through part is of a through structure, and the left side and the right side of the hoisting through part are communicated with the outside; and the hoisting middle through part is filled with sand. According to the invention, sand removal is guided in the through part of the through type hoisting, comprehensive sand removal does not need to be carried out on an inner cavity of a large casting, the sand removal workload is obviously reduced, the labor intensity of casting box opening can be obviously reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of cast iron metallurgy, and particularly to a casting structure and method for improving the efficiency of mold opening and the obtained casting. Background Art

[0002] In the casting process, mold opening is a crucial step, which refers to the process of removing the casting from the sand mold after the casting has cooled to an appropriate temperature. Since lifting holes are usually provided on the casting during pouring for subsequent lifting and installation, after mold opening, workers need to clean the sand at the position of the lifting holes to ensure that the lifting tool can smoothly penetrate and complete the lifting operation.

[0003] However, as the volume of the casting increases, the amount of sand in its inner cavity also increases, making the sand cleaning work extremely difficult. Especially for large castings, the amount of sand in the inner cavity is huge, and the sand temperature is usually around 300 °C. The high-temperature environment makes the labor intensity of manual sand cleaning extremely high. Workers not only need to clean the sand at the position of the lifting holes but also need to clean a large amount of sand grains in the inner cavity of the casting, which is not only time-consuming and laborious but also increases the safety risk of the operation. Summary of the Invention

[0004] In order to solve the technical problems existing in the above background art, one of the purposes of the present invention is to provide a casting structure for improving the efficiency of mold opening, including a sand core area and a casting area. At least one lifting hole is provided on the casting area, and a lifting through part is fixedly installed at the lifting hole. The lifting through part has a through structure, and its left and right sides communicate with the outside. The lifting through part is filled with sand, and the core sand material in the sand core area is furan resin sand. In order to meet the requirements of casting production, the lifting through part needs to use high-temperature resistant materials, and the melting point of this material needs to be higher than the pouring temperature of the molten iron. The sand used for filling in the lifting through part can use chromite sand and other casting sands that meet the heat resistance requirements.

[0005] As a preferred solution, heat insulation coatings are respectively provided on the inner and outer sides of the lifting through part.

[0006] As a preferred solution, the heat insulation coating is zirconium powder coating. It is made by brushing zirconium-based coatings on the inner and outer walls of the lifting through part and combining with the method of winding glass fiber cloth.

[0007] As a preferred solution, the lifting through part is in a tubular shape, and the lifting through part is fixedly connected to the core frame in the sand core area.

[0008] As a preferred solution, the material of the lifting through part is steel.

[0009] As a preferred solution, the inner hole of the lifting through part is coaxially arranged with the lifting hole, and the outer diameter of the lifting through part is adapted to the aperture of the lifting hole.

[0010] To solve the above technical problems, the second object of the present invention is to provide a casting method for improving the unpacking efficiency, including the following steps: S1. Install a hoisting through part in the hoisting hole of the casting area. The hoisting through part has a through structure and its left and right sides communicate with the outside. Fill the hoisting through part with sand; S2. Cast and form; S3. After the casting is cooled to the unpacking temperature, remove the sand in the hoisting through part; S4. Pass the sling into the inside of the hoisting through part and hoist the casting through the hoisting hole.

[0011] As a preferred solution, in S1, the hoisting through part is installed by means of a core box.

[0012] As a preferred solution, in S1, first apply zircon powder coating in the hoisting through part and then pour sand, weld the hoisting through part and the core bone together, and embed them in the core box.

[0013] To solve the above technical problems, the third object of the present invention is to provide a casting, which is obtained according to the casting method of the above technical solution.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. High-efficiency sand cleaning: Guide sand cleaning through the through-type hoisting through part. For large castings, the sand cleaning workload is significantly reduced; 2. Reduce labor intensity: Workers do not need to manually clean in the high-temperature area, and the safety is significantly improved; 3. Simple structure and cost saving: Just provide a hoisting through part on the original traditional casting structure, and the hoisting through part can be reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic diagram of the casting structure of Embodiment 1 of the present invention; Figure 2 It is an assembly schematic diagram of the casting of Embodiment 1 of the present invention with a sling on; Figure 1 ; Figure 3 It is an assembly schematic diagram of the casting of Embodiment 1 of the present invention with a sling on; Figure 2 ; Figure 4Exploded assembly view of the casting of Example 1 of the present invention with a lifting chain attached; Figure 5 Schematic cross-sectional structure diagram of the through-middle part for hoisting in Example 1 of the present invention; Figure 6 Schematic cross-sectional structure diagram of the through-middle part for hoisting in Example 4 of the present invention; Figure 7 Schematic cross-sectional structure diagram of the through-middle part for hoisting in Comparative Example 2 of the present invention.

[0017] In the figure: 1 - Core sand area; 2 - Casting area; 3 - Through-middle part for hoisting; 4 - Chrome ore sand; 5 - Heat insulation coating; 6 - Lifting chain; 7 - Glass fiber cloth. Detailed implementation manners

[0018] The present invention will be further elaborated below in conjunction with embodiments. These embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. For the experimental methods without specific conditions indicated in the following embodiments, they are generally in accordance with the conventional conditions in the art or the conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as the conventional market. Any non-substantive changes and substitutions made by those skilled in the art on the basis of the present invention fall within the scope of protection required by the present invention.

[0019] Examples 1 - 4 and Comparative Examples 1 - 2 Example 1: Casting of the boring machine column 1. Structure and parameter design As Figures 1-5 shown, the casting structure of this embodiment includes a core sand area 1 and a casting area 2. The core sand material of the core sand area 1 is furan resin sand. A hoisting hole is provided in the casting area 2, and a through-middle part for hoisting 3 is fixedly installed at the hoisting hole. The through-middle part for hoisting 3 has a through structure, and its left and right sides communicate with the outside. The through-middle part for hoisting 3 is filled with sand, and the sand used for filling is chrome ore sand 4. The inner hole of the through-middle part for hoisting 3 is coaxially arranged with the hoisting hole, and the outer diameter of the through-middle part for hoisting 3 is adapted to the aperture of the hoisting hole; Weight of the casting in the casting area: 55 tons, amount of inner cavity sand: 64 tons; Hoisting hole: aperture 211 mm, number 4; Through-middle part for hoisting 3: steel pipe, made of Q345B steel, outer diameter 210 mm, inner diameter 150 mm, length 2300 mm, filled with sand inside; Heat insulation coating 5: silicon nitride coating, coated on the inner and outer surfaces of the through-middle part for hoisting 3.

[0020] 2. Operation process Step 1: Install a hoisting through part 3 in the hoisting hole of the casting area 2. The left and right sides of the hoisting through part 3 are connected to the outside. Among them, first coat the inner and outer surfaces of the hoisting through part 3 with a heat insulation coating 5 and then pour chromite sand 4. Weld the hoisting through part 3 and the core bone in the core sand area 1 together and embed them in the core box; Step 2: Pour molten iron (temperature 1400 °C). After pouring, let it stand and cool to obtain a casting; Step 3: After cooling to 280 °C, use a high-pressure air gun with 0.7 MPa to remove the sand inside the hoisting through part 3; Step 4: Pass a lifting chain 6 with a diameter of 82 mm through the inside of the hoisting through part 3 and hoist the casting through the hoisting hole.

[0021] The assembly schematic diagram of the casting with the lifting chain in this embodiment is as Figures 1-3 shown.

[0022] Example 2: Casting of the boring machine column The difference from Example 1 is that the inner and outer surfaces of the hoisting through part are not coated with a heat insulation coating.

[0023] Example 3: Casting of the boring machine column The difference from Example 1 is that the heat insulation coating 5 applied is zircon powder coating.

[0024] Example 4: Casting of the boring machine column As Figure 6 shown, the difference from Example 3 is that after applying the zircon powder coating of the heat insulation coating 5 on the inner and outer walls of the hoisting through part 3, a layer of fiberglass cloth 7 with a thickness of about 1 mm is wrapped.

[0025] Comparative Example 1: Casting of the boring machine column The difference from Example 1 is that no hoisting through part is installed at the hoisting hole, and it is a conventional casting structure.

[0026] Comparative Example 2: Casting of the boring machine column As Figure 7 shown, the difference from Example 4 is that a layer of fiberglass cloth 7 with a thickness of about 1 mm is first wrapped on the outer wall of the hoisting through part 3, and then the zircon powder coating of the heat insulation coating 5 is applied.

[0027] The production situations of the above examples and comparative examples are shown in the following table Table 1 - Production situations of Examples 1 - 4 and Comparative Examples 1 - 2

[0028] Through the comparison between Examples 1 - 4 and Comparative Example 1 of this application, the significant advantages of the technical solution of the present invention in sand cleaning efficiency, labor intensity, and structural optimization are verified. The following is a specific analysis: Examples 1 - 4 set up a through - type hoisting middle part, reducing the sand - cleaning range from the hoisting holes and their adjacent areas (about 20 tons of sand) in traditional casting to the inside of the through - type hoisting middle part. The sand - cleaning weight is only 60 kg, which is only 0.09% of that in Comparative Example 1. In terms of sand - cleaning time, Examples 1 - 4 (2 - 5 hours) are shortened by 50% - 80% compared with Comparative Example 1 (10 hours), and the workload of sand - cleaning is also significantly reduced. The sand - cleaning weight is reduced from the original 20,000 kg to 60 kg, and the number of sand - cleaning workers required can also be greatly reduced. Among them, Examples 3 - 4 use zircon powder coating or a heat - insulating layer combined with fiberglass cloth, and the sand - cleaning time is further optimized to 2 hours, indicating that the heat - insulating coating can effectively prevent the sintering of the sand core and improve the cleaning efficiency of the sand in the steel pipe. In Comparative Example 1, due to the absence of the through - type hoisting middle part, all sand cores need to be manually cleaned. Workers need to manually dig sand from both sides of the boring machine column, remove the sand grains on both sides of the column, the core bones inside the column, and the flash on the surface of the column until reaching the hoisting hole position. Generally, the sand - cleaning process outside the hoisting hole is relatively smooth, but the sand - cleaning work at the hoisting hole is time - consuming. In addition, the temperature is relatively high when opening the box, and considering the large size of the column casting itself, the cleaning is very time - consuming and labor - intensive. Workers need to position at the hoisting hole. After positioning, insert the lifting chain into the hoisting hole for lifting operation. The whole process is inefficient and has a very high labor intensity.

[0029] The implementation example scheme, through the through - structure of the through - type hoisting middle part, enables the sand - cleaning operation to only remove the sand in the steel pipe through a high - pressure air gun, and workers do not need to enter the high - temperature casting cavity for manual cleaning. In contrast, Comparative Example 1 needs to handle a complex inner cavity structure, and the operating environment is high - temperature and dangerous, with serious safety hazards. The clear cleaning path in the implementation example further simplifies the process and reduces the operation difficulty. In addition, although the time consumption in Example 2 increases due to the sintering of the sand core, it is still better than the traditional process, indicating that even without using a heat - insulating coating, this scheme can still significantly reduce the labor intensity.

[0030] The scheme of this embodiment only adds a through - type hoisting middle part to the traditional casting structure, with small structural changes and easy implementation. The steel pipe can be reused, avoiding the problems of repeated reinforcement or material waste of the hoisting holes in the traditional process. The one - time processing cost of the steel pipe in the implementation example is in sharp contrast to the repeated processing cost in Comparative Example 1, with significant economy.

[0031] The introduction of heat-insulating coatings (such as the silicon nitride coating in Example 1 and the zircon powder coatings in Examples 3-4) effectively blocks the heat exchange between the high-temperature molten iron (1400 °C) and the steel pipe, reduces the local heat stress concentration, and makes the tissue uniformity of the casting significantly better than that of Example 2 without coating. Among them, in Example 4, the heat-insulating layer is reinforced with fiberglass cloth. The fiberglass cloth and the zircon powder coating are used in combination to form a strong high-temperature resistant protective shell on the outside of the steel pipe, and the tissue of the casting reaches the "excellent" grade. In contrast, in Comparative Example 1, due to the lack of a heat-insulating structure, there are problems of heat stress concentration in the casting, and the strength at the lifting hole is low, requiring additional reinforcement, highlighting the double advantages of this solution in terms of quality and structural stability.

[0032] Comparing Example 4 and Comparative Example 2, it can be seen that the process sequence of "applying heat-insulating paint first and then winding fiberglass cloth" has better technical effects than "winding cloth first and then applying paint": the heat-insulating paint is directly coated on the metal surface of the middle part of the lifting through-hole to form a dense basic heat-insulating layer, blocking the heat conduction from the high-temperature molten iron to the steel pipe. Moreover, the fiberglass cloth is wound on the outer surface of the coating to form a mechanical protective layer to prevent the coating from peeling off during high-temperature pouring or sand cleaning. The elasticity of the fiberglass cloth can absorb the stress generated by the thermal expansion difference between the coating and the steel pipe, avoiding cracking of the coating.

[0033] If the reverse operation of winding cloth first and then applying paint is carried out, an air layer or heat bridge will be formed in the gap between the fiberglass cloth and the middle part of the lifting through-hole, resulting in heat penetrating through the pores of the cloth, reducing the heat-insulating efficiency. In addition, the paint only covers the outer surface of the fiberglass cloth layer and cannot penetrate into the fiber gaps, with poor adhesion and easy to fall off at high temperatures. Winding fiberglass cloth outside the zircon powder coating, although it increases the material cost slightly, further improves the heat-insulating performance and does not affect the structural reusability, reflecting the balance between process optimization and cost control.

[0034] The technical solution of the present invention realizes the core advantages of more than 80% improvement in sand cleaning efficiency, time-saving and labor-saving, almost completely removing workers from the high-temperature and high-risk environment, and almost zero increase in the structural transformation cost by setting a middle part for guiding sand cleaning in the lifting through-hole. The example data fully prove that this solution is innovative, practical and economical in the casting of large castings (such as the column of a 55-ton boring machine), providing an efficient, safe and low-cost process optimization path for the industry.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A casting structure for improving the unpacking efficiency, characterized in that, Comprising: A core sand area and a casting area, and at least one lifting hole is provided on the casting area; A lifting through part is fixedly installed at the lifting hole. The lifting through part has a through structure, with its left and right sides communicating with the outside. The inside of the lifting through part is filled with sand, and the core sand material in the core sand area is furan resin sand.

2. The casting structure according to claim 1, wherein: Heat insulation coatings are respectively provided on the inner and outer sides of the lifting through part.

3. The casting structure according to claim 2, wherein: The heat insulation coating is zircon powder coating.

4. The casting structure according to claim 1, wherein: The lifting through part is tubular, and the lifting through part is fixedly connected to the core frame in the core sand area.

5. The casting structure according to claim 1, wherein: The material of the lifting through part is steel.

6. The casting structure according to claim 4, wherein: The inner hole of the lifting through part is coaxially arranged with the lifting hole, and the outer diameter of the lifting through part is adapted to the aperture of the lifting hole.

7. A casting method for improving the unpacking efficiency, characterized in that, Including the following steps: S1. Install a lifting through part in the lifting hole of the casting area. The lifting through part has a through structure and its left and right sides communicate with the outside. The inside of the lifting through part is filled with sand; S2. Cast and form; S3. After the casting is cooled to the unpacking temperature, remove the sand inside the lifting through part; S4. Pass a lifting tool into the inside of the lifting through part, and lift the casting through the lifting hole.

8. The method according to claim 7, wherein In S1, the lifting through part is installed by means of a core placing box.

9. The method according to claim 8, wherein In S1, first apply zircon powder coating inside the lifting through part and then pour sand, weld the lifting through part and the core frame together, and embed them in the core box.

10. A casting obtained by the casting method according to any one of claims 7-9.

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