Boss casting structure

Abstract

The utility model relates to the technical field of black or colored casting, in particular to a boss casting structure which comprises a mold and a chilling block, the chilling block is made of the same material as a product, one end of the chilling block is embedded into a mounting groove, and the other end of the chilling block extends into a boss forming cavity and is used for being fused with molten iron to form a boss of the product. According to the boss casting structure, the chilling block made of the same material as a product is selected, one end of the chilling block is embedded into the mounting groove, the other end of the chilling block extends into the boss forming cavity, the semi-embedded design of the chilling block is achieved, and therefore it can be guaranteed that the chilling block fully plays a role; and meanwhile, the shrinkage characteristics of the chilling block and the product in the solidification process are similar, the shrinkage cavity hidden danger caused by material difference can be effectively reduced, the product yield is improved, and the problem that the rejection rate of the product with the boss is high is solved.

Description

Technical Field

[0001] This utility model relates to the field of ferrous or non-ferrous casting technology, and in particular to a boss casting structure. Background Technology

[0002] In the manufacturing process of ferrous and non-ferrous casting products, shrinkage cavities around bosses are a common problem. These cavities primarily result from inconsistent solidification rates in the boss area during product molding. The molten metal does not receive sufficient replenishment during solidification and shrinkage, leading to the formation of shrinkage cavities. The hazards of shrinkage cavities are particularly pronounced for products with extremely high internal quality requirements, especially those requiring X-ray flaw detection and strict airtightness. For example, shrinkage cavities will appear as obvious defects during X-ray flaw detection, directly causing the product to fail inspection. Simultaneously, shrinkage cavities will compromise the product's airtightness, making it unsuitable for specific application scenarios. These problems not only severely weaken the product's structural strength but can also cause appearance defects, leading to a significant increase in scrap rates and production costs.

[0003] In the industry, the conventional method for compensating for bosses is to use risers. For example, the utility model disclosed in CN205887975U is an aluminum alloy water inlet pipe with a riser structure. By changing the structure of the traditional boss part, it adds a compensating riser to the boss part, so that the molten aluminum can directly compensate for the hot metal and improve the boss shrinkage problem.

[0004] As described above, the effect of using feeding risers to improve the shrinkage problem of bosses is limited in the actual casting process. Therefore, the scrap rate of such products with bosses is still relatively high. For this reason, it is necessary to provide a boss casting structure. Utility Model Content

[0005] In view of this, this utility model proposes a boss casting structure, which uses chills of the same material as the product, with one end embedded in the mounting groove and the other end extending into the boss forming cavity to achieve a semi-embedded design of the chills. This ensures that the chills can fully play their role and avoids problems such as localized low temperature and stress concentration caused by the chills being fully embedded. At the same time, the shrinkage characteristics of the chills and the product are similar during solidification, which can effectively reduce the risk of shrinkage cavities caused by material differences, improve product yield, and solve the problem of high scrap rate of products with bosses.

[0006] The technical solution of this utility model is implemented as follows:

[0007] This utility model provides a boss casting structure, including a mold and a chill, wherein...

[0008] The mold has a product cavity inside, and a boss forming cavity is provided on the cavity wall corresponding to the boss part of the product cavity. An installation groove is provided on the cavity wall of the boss forming cavity.

[0009] The chill is made of the same material as the product, with one end embedded in the mounting groove and the other end extending into the boss forming cavity, for fusing with molten iron to form the boss of the product.

[0010] Based on the above technical solutions, preferably, the length of the chill extending into the boss forming cavity is 1 / 2 to 1 / 3 of the thickness of the boss part of the product.

[0011] Based on the above technical solutions, preferably, the chill is columnar.

[0012] Based on the above technical solutions, preferably, the side of the chill extending into the boss forming cavity is provided with a protrusion or a groove.

[0013] Based on the above technical solutions, preferably, the protrusion is hemispherical, and several protrusions are evenly distributed on the side of the chill.

[0014] Based on the above technical solutions, preferably, the groove is an annular groove or a spiral groove.

[0015] Based on the above technical solutions, preferably, the annular grooves are distributed at intervals along the axial direction of the chill.

[0016] Based on the above technical solutions, preferably, the edge of the chill embedded in the mounting groove is provided with a chamfer structure.

[0017] Based on the above technical solutions, preferably, the side surface of the chill embedded in the mounting groove is evenly distributed with several barbs.

[0018] Based on the above technical solution, preferably, a feeding riser is provided inside the mold and near the boss forming cavity, wherein,

[0019] The feeding riser is connected to the product cavity.

[0020] The boss casting structure of this utility model has the following advantages over the prior art:

[0021] (1) By using chills made of the same material as the product, it is ensured that the chills and the product have similar coefficients of thermal expansion and shrinkage rates during solidification, eliminating interfacial shrinkage stress caused by material differences and significantly reducing the risk of shrinkage cavities and microcracks. At the same time, one end of the chill is embedded in the mounting groove, and the other end extends into the boss forming cavity, realizing a semi-embedded design of the chill. This ensures that the chill can play its full role and avoids problems such as local low temperature and stress concentration caused by the chill being fully embedded. In addition, the shrinkage characteristics of the chill and the product are similar during solidification, which can effectively reduce the risk of shrinkage cavities caused by material differences and improve product yield.

[0022] (2) By controlling the length of the chill extending into the boss forming cavity to within 1 / 2 to 1 / 3 of the boss thickness, it ensures that the exposed part of the chill is in full contact with the high-temperature molten iron to enhance its thermal conductivity, while avoiding insufficient feeding caused by excessively long chills leading to excessively fast solidification rates. This design works in conjunction with the feeding riser to optimize the solidification sequence, extend the riser feeding distance, and further reduce shrinkage defects.

[0023] (3) By setting protrusions or grooves on the surface of the chill, the contact area between the chill and the molten iron is increased, the interfacial metallurgical bonding is promoted, the degree of fusion is improved, and shrinkage defects are reduced.

[0024] (4) By setting barbs on the surface of the chill, the mechanical engagement between the chill and the mold is enhanced, preventing the chill from shifting under the impact of molten iron or the vibration of the mold, ensuring the precise and stable position of the chill, thereby ensuring the uniformity and reliability of the cooling effect, and avoiding local uneven cooling or shrinkage defects caused by the displacement of the chill. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a front view of a boss casting structure according to the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the product after casting.

[0028] Figure 3 This is a schematic diagram of the chill structure;

[0029] In the diagram: 1. Mold; 2. Chill; 101. Product cavity; 102. Boss forming cavity; 103. Mounting groove; 104. Feeding riser; 201. Protrusion; 202. Groove; 203. Barb. Detailed Implementation

[0030] The technical solutions of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0031] like Figure 1-3 As shown, the present invention provides a boss casting structure, which includes a mold 1 and a chill 2.

[0032] The mold 1 has a product cavity 101 inside. The cavity wall of the product cavity 101 corresponding to the product boss is provided with a boss forming cavity 102. The cavity wall of the boss forming cavity 102 is provided with an installation groove 103. The chill 2 is made of the same material as the product. One end of the chill is embedded in the installation groove 103 and the other end extends into the boss forming cavity 102. It is used to fuse with molten iron to form the boss of the product.

[0033] In this structure, chill 2, made of the same material as the product, is used to ensure that chill 2 and the product have similar coefficients of thermal expansion and shrinkage rates during solidification. This eliminates interfacial shrinkage stress caused by material differences, significantly reducing the risk of shrinkage cavities and microcracks. Simultaneously, one end of chill 2 is embedded in the mounting groove 103, while the other end extends into the boss forming cavity 102, achieving a semi-embedded design. This ensures that chill 2 functions effectively while avoiding problems such as excessively low local temperatures and stress concentration caused by complete embedding. Furthermore, the similar shrinkage characteristics of chill 2 and the product during solidification effectively reduce the risk of shrinkage cavities caused by material differences, improving product yield and solving [the problem]. Figure 2 This addresses the issue of high scrap rates during the casting process for products with bosses.

[0034] like Figure 1 As shown, the length of the chill 2 extending into the boss forming cavity 102 is 1 / 2 to 1 / 3 of the thickness of the boss portion of the product. This controls the length of the chill 2 extending into the boss forming cavity 102 within a reasonable range, ensuring that the exposed part of the chill 2 is in full contact with the high-temperature molten iron to enhance heat conduction, while avoiding insufficient feeding caused by excessively long chill 2 leading to excessively fast solidification rate.

[0035] like Figure 3 As shown, the chill 2 is columnar, and a protrusion 201 or a groove 202 is provided on the side of the end that extends into the boss forming cavity 102. This structure can increase the contact area between the chill 2 and the molten iron, promote interfacial metallurgical bonding, improve the degree of fusion, and reduce shrinkage defects.

[0036] When the chill 2 extends into the side of the boss forming cavity 102 and a protrusion 201 is provided, the protrusion 201 is hemispherical, and several protrusions 201 are evenly distributed on the side of the chill 2. This surface structure can serve as a heterogeneous nucleation point, accelerating the solidification of molten iron and refining the grains, thereby improving the density and mechanical properties of the boss.

[0037] When the chill 2 extends into the side of the boss forming cavity 102, a groove 202 is provided. The groove 202 is either an annular groove or a spiral groove. Several annular grooves are spaced apart along the axial direction of the chill 2. In this structure, when a spiral groove is used, the groove guides the molten iron to form a spiral temperature gradient, optimizing the feeding direction. When an annular groove is used, it promotes uniform circumferential solidification, avoiding localized shrinkage stress concentration, and has a similar principle to the solidification guidance mechanism of a stepped casting system.

[0038] In addition, the groove edge of the groove 202 undergoes local melting under the scouring of molten iron, forming a transition alloy layer between chilled iron and casting, which improves the interfacial bonding strength and reduces porosity and interfacial crack defects.

[0039] like Figure 3 As shown, a chamfered structure is provided at one end of the chill 2 that is embedded in the mounting groove 103. After chamfering, this end is shaped like a frustum, which facilitates the embedding of the chill 2 into the mounting groove 103 and makes the installation of the chill 2 easier.

[0040] like Figure 3 As shown, the side surface of the chill 2 embedded in the mounting groove 103 is evenly distributed with several triangular barbs 203. Their function is to enhance the mechanical engagement between the chill and the mold 1, prevent the chill 2 from shifting under the impact of molten iron or the vibration of the mold 1, ensure the precise and stable position of the chill 2, thereby ensuring the uniformity and reliability of the cooling effect, and avoiding local uneven cooling or shrinkage defects caused by the displacement of the chill 2.

[0041] like Figure 1 As shown, a feeding riser 104 is provided inside the mold 1, near the boss forming cavity 102. Specifically, the feeding riser 104 is connected to the product cavity 101, and is located above the boss forming cavity 102, with its upper end extending upwards through the top of the mold 1. This structure, in conjunction with the length control of the chill 2 extending into the boss forming cavity 102, optimizes the solidification sequence, extends the feeding distance of the riser, and further reduces shrinkage defects.

[0042] The method of using the boss casting structure of this utility model is as follows:

[0043] In mold 1, a product cavity 101, a boss forming cavity 102, and a mounting groove 103 are created. Then, a chill of suitable length is prepared, with one end embedded in the mounting groove 103 and the other end remaining in the boss forming cavity 102. After molten iron is injected into the product cavity 101, it fuses with the chill to form the boss structure of the product. When the product is unmolded, as... Figure 2 As shown, the excess portion of the chilled iron 2 protruding from the product is removed using a cutting device.

[0044] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A boss-casting structure comprising a mould (1), characterised in that: It also includes chills (2), in which, The mold (1) is provided with a product cavity (101) inside. The product cavity (101) is provided with a boss forming cavity (102) on the cavity wall corresponding to the product boss part. The boss forming cavity (102) is provided with an installation groove (103) on the cavity wall. The chill (2) is made of the same material as the product, and one end of it is embedded in the mounting groove (103), while the other end extends into the boss forming cavity (102) for fusion with molten iron to form the boss of the product.

2. A bossed casting structure as claimed in claim 1, wherein: The length of the chill (2) extending into the boss forming cavity (102) is 1 / 2 to 1 / 3 of the thickness of the boss part of the product.

3. A bossed casting structure as claimed in claim 2, wherein: The chill (2) is columnar.

4. A boss casting structure according to claim 3, wherein: The side of the chill (2) extending into the boss forming cavity (102) is provided with a protrusion (201) or a groove (202).

5. A boss casting structure according to claim 4, wherein: The protrusion (201) is hemispherical, and several protrusions (201) are evenly distributed on the side of the chill (2).

6. A boss casting structure according to claim 4, wherein: The groove (202) is an annular groove or a spiral groove.

7. A boss casting structure according to claim 6, wherein: The annular grooves are distributed at intervals along the axial direction of the chill (2).

8. A boss casting structure according to claim 3, wherein: The chill (2) is fitted with a chamfered structure at one end of the mounting groove (103).

9. A boss casting structure according to claim 1, wherein: The side surface of the chill (2) embedded in the mounting groove (103) is evenly distributed with several barbs (203).

10. A boss casting structure according to claim 1, wherein: A feeding riser (104) is provided inside the mold (1) and near the boss forming cavity (102), wherein the feeding riser (104) is connected to the product cavity (101).

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