Casting mold structure for preventing sand hole defect on surface of large-plane casting
By setting ribs and high-temperature stable coatings on the large plane of the casting mold, the problem of sand hole defects in large plane castings is solved, and the casting surface is smooth and beautiful and high-quality casting production is achieved.
Patent Information
- Application Number
- CN202422511613.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-17
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2034-10-17
AI Technical Summary
Large-plan castings are prone to sand hole defects during casting, and the prior art is difficult to effectively prevent, affecting the quality and service life of the castings.
Multiple ribs are arranged on the large planar surface of the casting mold to form fine grooves to buffer high-temperature expansion stress, and combine with paint with good high-temperature stability to avoid cracking of the sand-shaped surface and falling off the paint.
It effectively avoids defects such as sand holes on the surface of the casting, improves the appearance quality and service life of the casting, and meets the needs of the high-end equipment manufacturing industry.
Smart Images
Figure CN223250481U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a casting mold structure, in particular to a casting mold structure for preventing sand hole defects on the surface of a large-plane casting, and belongs to the field of sand casting. Background Art
[0002] The foundry industry, especially sand casting, is prone to small blisters. This is because after high-temperature molten iron is poured into the sand mold, the sand layer on the surface of the mold cavity is subjected to the instantaneous and intense high temperature, causing it to expand rapidly. This expansion stress can cause local bulges or cracks in the surface sand layer, resulting in defects such as blisters on the casting surface. Castings with large flat surfaces are particularly prone to surface defects because curved surfaces facilitate the release of high-temperature expansion stress in the molding sand, while flat surfaces hinder this release. Therefore, castings with large flat surfaces are prone to surface defects such as blisters.
[0003] Existing technologies generally use high-temperature resistant coatings and rapid pouring to prevent such surface defects in castings. However, the coating layer is very thin and its effect is quite limited. The sand layer is subjected to high-temperature molten iron and the expansion stress is large, which will break the coating layer and cause the coating to fall off. The coating and rapid pouring methods are difficult to completely eliminate the surface defects of castings caused by the high-temperature expansion of the sand layer.
[0004] Surface defects in castings not only affect their appearance but also their service life. These defects can become stress concentration points during the casting's service life. Once these stresses reach a certain limit, they can develop into crack sources, causing the casting to break. Therefore, continuously improving the appearance quality of castings is a key, long-term research topic in the casting industry. Summary of the Invention
[0005] In view of the problem that small sand holes are easily generated on the surface of large flat castings in the sand casting industry, which affects product quality, the utility model provides a casting mold structure for preventing sand hole defects on the surface of large flat castings. This mold structure is formed by arranging multiple ribs on the large flat surface of the casting mold, and forming fine grooves within a certain depth on the surface of the sand mold after molding. In this way, a high-temperature expansion stress retreat space is formed on the surface layer of the sand mold, so that the expansion stress of the sand mold has room to buffer and will not break or explode and fall off, thereby avoiding defects on the casting surface caused by the expansion of the sand mold, improving the quality of the casting, increasing the service life of the product, and meeting the quality requirements of users.
[0006] The technical solution of the utility model is: a casting mold structure for preventing sand hole defects on the surface of a large flat casting, comprising ribs on the surface of the casting mold, wherein the casting mold surface has one or more large flat surfaces, and one or more ribs are respectively arranged at the positions of the one or more large flat surfaces, the ribs being higher than the large flat surfaces of the mold, the ribs being arranged in one or more directions of the large flat surfaces of the casting mold, the sizes and shapes of the multiple ribs being the same or different, the ribs being provided with a draft angle, the rib height being equal to or less than 2 / 3 of the thickness of the sand layer at the location, the rib length being less than or equal to 2 / 3 of the surface size of the location, and the rib thickness being less than the wall thickness of the casting at the location;
[0007] Furthermore, the ribs are in a linear structure, a curved structure or a broken line structure.
[0008] The positive effects of the utility model are as follows: by arranging ribs higher than the surface of the large plane on the large plane of the casting mold, grooves can be formed on the surface of the sand mold after sand molding, which is beneficial to the release of the high-temperature expansion stress of the molding sand when pouring high-temperature molten iron, and can avoid local bulging or cracking of the sand layer on the surface of the sand mold, and further can avoid casting defects such as sand holes in the casting; by arranging a draft angle on the ribs, it is beneficial to the removal of the casting mold and convenient for the molding of the sand mold; by limiting the height of the ribs to be equal to or less than 2 / 3 of the thickness of the sand layer at the location, limiting the length of the ribs to be less than or equal to 2 / 3 of the surface size of the location, and limiting the thickness of the ribs to be less than the wall thickness of the casting at the location, it is beneficial to release the high-temperature expansion stress of the molding sand and facilitate the removal of the ribs from the casting, the sand mold surface and the coating layer will not crack or fall off, and the casting will not have surface sand holes, sand inclusions, cold shuts and air hole defects, thereby ensuring the quality of the casting surface, producing high-quality castings with smooth and beautiful surfaces, and meeting the needs of the high-end equipment manufacturing industry. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 This is a three-dimensional diagram of the sand mold structure of the jet-propelled high-end textile machine wall panel.
[0010] Figure 2 It is a three-dimensional picture of the wall panel casting of a jet-propelled high-end textile machine.
[0011] Description of the numbers: 01-mold base plate, 02-rib, 03-casting mold, 04-casting rib. DETAILED DESCRIPTION
[0012] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0013] 1. Process review: Based on empirical analysis, determine the areas of the casting that are prone to defects such as pores, sand holes, sand inclusions, and cold shuts, and evaluate whether to adopt the structure of adding surface ribs 02 when making the casting mold 03.
[0014] 2. Making the casting mold: When making the casting mold 03, determine the number and size of the ribs 02 based on the initial assessment, and set the ribs 02 on the corresponding surfaces of the mold where casting defects are likely to occur.
[0015] 3. Follow the normal procedures of molding, box assembly, pouring, sand removal and cleaning, remove the casting ribs 04 on the surface of the casting, and polish it smooth to obtain a qualified casting product.
[0016] The implementation method of the utility model is:
[0017] 1. When making the casting mold 03, ribs 02 are installed on the surface of the corresponding parts where defects are likely to occur. After molding, fine grooves are formed on the surface of the sand mold. These grooves provide space for the sand mold to expand when heated after pouring molten metal. This prevents the sand mold and coating from cracking, exploding, or falling off after pouring, and the casting will not have surface defects.
[0018] 2. Brush the upper surface of the sand mold with a coating that has good high-temperature stability. This coating has stable performance and high strength at high temperatures. The high-temperature expansion of the sand mold will not destroy the integrity of the coating, thus ensuring that the surface of the casting is smooth and free of defects.
[0019] Figure 1 It is a three-dimensional diagram of the sand mold structure of the jet high-end textile machine wall panel, Figure 2 A three-dimensional diagram of a jet-propelled high-end textile machine wall panel casting, wherein 01 is the mold base, and the ribs 02 on the surface of the casting mold 03 can be on the casting surface in any direction, and the ribs 02 can be straight, curved, or broken line-shaped.
[0020] The dimensions of the mold surface ribs 02 and the casting surface ribs 04 can be flexibly optimized based on the actual casting. Generally, the height of rib 02 is equal to or less than 2 / 3 of the sand layer (sand intake) at the location, and the length is less than or equal to 2 / 3 of the surface dimension of the location. Ribs 02 should not be too long, with a length of less than 200mm and a height of less than 100mm. The number of ribs 02 can be determined based on the size of the location, and their orientation is not fixed. The draft angle of rib 02 can be greater than that of the pattern to facilitate demolding after shaping.
[0021] ①Process analysis and evaluation, process design and drawing of process drawings, and then drawing of mold drawings;
[0022] ② Prepare the various raw materials required for casting mold 03 and casting production.
[0023] ③ Make casting mold 03 for production and inspect the mold for qualification
[0024] ④ Sand mixing, molding, coating, melting molten metal, sand mold assembly, and pouring;
[0025] ⑤ After the insulation reaches the specified time, unpack, shake off the sand, clean, remove the casting ribs 04 on the surface of the casting, and polish to obtain qualified casting products.
[0026] The 3604 wall panel castings produced by our company, such as Figure 2 , with a local plane structure, the wall thickness of this part is relatively thin, which is prone to cold shut and sand hole defects. A rib 02 with a length of 80 to 150 mm, a thickness of 7 to 4 mm, and a height of 35 mm is added to the plane of the casting mold 03 where cold shut defects are prone to occur. After that, the castings produced no longer have cold shut and sand hole defects, and the appearance quality is good.
[0027] Reference Figure 1 There are sand cores inside two local places, which are located at the highest point during pouring, which is prone to porosity defects. Later, ribs 02 were added to the upper surface of the casting mold 03 at these two places. The dimensions of rib 02 are 85mm in length, 25mm in height, and 8~4mm in thickness. As a result, the porosity defects on the surfaces of these two places were eliminated.
[0028] The above embodiments are only some examples of the present invention and are not intended to limit the scope of the present invention. The ribs 02 are provided on the casting mold 03 at locations where casting defects are likely to occur. The ribs 02 can be flexibly sized and positioned to suit various castings and can be used in various sand casting processes.
[0029] In this embodiment, the ribs 02 are made of the same material as the casting mold 03, but other materials may also be used.
[0030] The positive effects of the present invention are as follows: by arranging a rib sheet 02 higher than the surface of the large plane on the large plane of the casting mold 03, grooves can be formed on the surface of the sand mold after sand molding, which is beneficial to the release of the high-temperature expansion stress of the molding sand when pouring high-temperature molten iron, and can avoid local bulging or cracking of the sand layer on the surface of the sand mold, and further can avoid casting defects such as sand holes in the casting; by arranging a draft angle on the rib sheet, it is beneficial to the removal of the mold and convenient for the molding of the sand mold; by limiting the height of the rib sheet 02 to be equal to or less than 2 / 3 of the thickness of the sand layer at the location, limiting the length of the rib sheet 02 to be less than or equal to 2 / 3 of the surface size of the location, and limiting the thickness of the rib sheet 02 to be less than the wall thickness of the casting at the location, it is beneficial to release the high-temperature expansion stress of the molding sand, the sand mold surface and the coating layer will not crack or fall off, and the casting will not have surface sand holes, sand inclusions, cold shuts and air holes defects, thereby ensuring the quality of the casting surface, producing high-quality castings with smooth and beautiful surfaces, and meeting the needs of the high-end equipment manufacturing industry.
Claims
1. A casting mold structure for preventing sand hole defects on the surface of a large flat casting, comprising ribs on the surface of the casting mold, characterized in that: The surface of the casting mold has one or more large flat surfaces, and one or more ribs with a height higher than the large flat surface of the mold are respectively arranged at the position of the one or more large flat surfaces. The ribs are arranged in one or more directions of the large flat surface of the casting mold. The sizes and shapes of the multiple ribs are the same or different. The ribs are provided with a draft angle, the height of the ribs is equal to or less than 2 / 3 of the thickness of the sand layer at the location, the length of the ribs is less than or equal to 2 / 3 of the surface size of the location, and the thickness of the ribs is less than the wall thickness of the casting at the location.
2. A casting mold structure for preventing sand hole defects on the surface of a large flat casting according to claim 1, characterized in that: The ribs are in a linear structure, a curved structure or a broken line structure.