Casting solidification sequence regulation and control composite casting mold and casting method

Abstract

The invention relates to the technical field of casting, and discloses a casting solidification sequence regulation and control composite casting mold and a casting method.The composite casting mold comprises a plurality of sand molds made of different materials, and the multiple sand molds are assembled together up and down; the sand molds and the metal molds are made of different materials, and the sand molds and the metal molds are assembled together up and down. Casting molds made of different materials (different materials have different cooling effects on the casting) are used at different positions of the casting, so that the temperature field and the solidification sequence of the casting are regulated and controlled, the solidification sequence of the casting is regulated and controlled in a simple and convenient mode, meanwhile, the quality of the casting is guaranteed, the assembly mode is flexible and variable, and the applicability is improved.

Description

Technical Field

[0001] This invention relates to the field of casting technology, specifically to a composite mold for controlling the solidification sequence of castings and a casting method. Background Technology

[0002] In sand casting, risers are used to compensate for the solidification shrinkage of the casting and eliminate defects such as shrinkage cavities and porosity. However, riser compensation requires a smooth feeding channel in the casting and a suitable solidification sequence. For example, the compensation of the top riser in the casting requires a bottom-up solidification sequence.

[0003] To control the solidification sequence of castings and improve the feeding distance and efficiency of risers, traditional casting processes often use chills to rapidly cool localized areas of the casting, thereby adjusting the overall solidification sequence. However, this method has several drawbacks, including: ① The use of chills requires a series of processes such as machining, surface treatment, and baking, consuming significant manpower and increasing the workload of sand molding; ② The chilling effect may reduce the fluidity of the molten metal, leading to defects such as cold shuts and incomplete filling in the casting; ③ The chilling effect is limited by its size and the casting structure, offering limited control over the solidification sequence of large, thick-walled castings; ④ It can easily lead to defects such as chilling cracks, affecting the internal structure and performance of the casting; ⑤ The placement of chills in 3D printed sand molds presents significant challenges. In addition, existing technologies have proposed various external intervention measures such as water cooling, air cooling, and local induction heating to regulate the temperature field of the mold and castings, thereby changing the solidification sequence of the castings. However, the implementation of the above measures often requires the use of specific process equipment, which increases the workload of the casting process and is prone to other casting quality problems, such as porosity caused by water vapor or other gases invading the castings during water cooling and air cooling.

[0004] Therefore, providing a composite mold and casting method for controlling the solidification sequence of castings is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a composite mold and casting method for controlling the solidification sequence of castings, which achieves control of the solidification sequence of castings in a simple and convenient manner, while ensuring the quality of castings and improving applicability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A composite mold for controlling the solidification sequence of castings, comprising:

[0008] Multiple sand molds made of different materials are assembled together, one on top of the other.

[0009] Multiple sand molds and metal molds of different materials are assembled together.

[0010] By adopting the above technical solutions, the present invention produces the following beneficial effects:

[0011] By using molds of different materials at different locations on the casting (different materials have different cooling effects on the casting), the temperature field and solidification sequence of the casting can be controlled. This achieves simple and convenient control of the solidification sequence of the casting while ensuring the quality of the casting. The assembly method is flexible and variable, improving its applicability.

[0012] Furthermore, the materials of the sand mold include ceramsite sand, silica sand, chromite sand, and zircon sand.

[0013] The casting method using a composite mold for controlling the solidification sequence of castings as described above includes the following steps:

[0014] According to the solidification sequence requirements of the casting, multiple sand molds of different materials are assembled vertically, or multiple sand molds and metal molds of different materials are assembled vertically, so as to control the temperature field of the casting by utilizing the different cooling capabilities of different materials during casting, so that it solidifies in the required solidification sequence.

[0015] Furthermore, for casting areas that require accelerated cooling, metal molds and / or cooling sand molds are selected, with the cooling sand mold material including zircon sand and chromite sand; for casting areas that require delayed cooling, heat-insulating sand molds are selected, with the heat-insulating sand mold material including ceramsite sand and silica sand.

[0016] Therefore, this invention provides a composite mold and casting method for controlling the solidification sequence of castings. Compared with the prior art, this invention has the following beneficial effects:

[0017] 1) This invention assembles sand molds and metal molds of different materials with different thermal conductivity and specific heat into a composite mold. By utilizing the different cooling capabilities of different materials for castings, the cooling rate of different parts of the casting can be controlled, thereby achieving the purpose of controlling the overall solidification sequence of the casting in a simple and convenient way.

[0018] 2) The assembly method of the composite mold can be adjusted according to the actual structure and solidification sequence requirements of the casting, making the casting process simple and not increasing the workload on site;

[0019] 3) For 3D printed sand molds, due to the many limitations in the application of chills, it is difficult to control the solidification sequence of castings by using chills. However, the present invention can conveniently control the solidification sequence of castings in 3D printed sand molds.

[0020] 4) The casting mold combination method is flexible and can be adapted to the needs of castings with different structures and sizes. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Figure 1 The attached figure is a schematic diagram of a composite mold for controlling the solidification sequence of castings in Example 1;

[0023] Figure 2 The attached figure is a cross-sectional view of a composite mold for controlling the solidification sequence of castings in Example 2;

[0024] Figure 3 The attached figure shows a composite mold for controlling the solidification sequence of a casting in Example 2, and the cooling rate curves of various positions (top, middle, and bottom) of the casting.

[0025] Figure 4 The attached figure shows the cooling rate curves of the existing sand mold and casting at various locations (top, middle, and bottom);

[0026] Figure 5 The attached figure is a cross-sectional view of a composite mold for controlling the solidification sequence of castings in Example 3;

[0027] Figure 6 The attached figure is a cross-sectional view of a composite mold for controlling the solidification sequence of castings in Example 4. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] like Figure 1As shown in the figure, this invention discloses a composite mold for controlling the solidification sequence of castings, comprising multiple sand molds and metal molds 1 of different materials, which are assembled together vertically. This invention controls the temperature field and solidification sequence of casting 5 by using molds of different materials at different locations on the casting (different materials have different cooling effects on the casting; the molds are ordered from strongest to weakest cooling capacity as follows: metal mold 1 → zircon sand mold 2 → chromite sand mold → silica sand mold 3 → ceramsite sand mold 4). This achieves simple and convenient control of the solidification sequence of casting 5 while ensuring the quality of casting 5. The assembly method is flexible and adaptable, improving its applicability.

[0031] This invention also discloses a casting method using a composite mold for controlling the solidification sequence of castings, comprising the following steps:

[0032] According to the solidification sequence requirements of casting 5, multiple sand molds and metal molds 1 of different materials are assembled vertically to regulate the temperature field of casting 5 during casting by utilizing the different cooling capacities of different materials, so that it solidifies in the required solidification sequence.

[0033] In this embodiment, there are four sand molds: two ceramsite sand molds 4 and two silica sand molds 3. The two ceramsite sand molds 4, the two silica sand molds 3, and the metal casting mold 1 are assembled together from top to bottom. The thermal conductivity of the composite mold gradually decreases from bottom to top, and the cooling capacity of the casting 5 gradually decreases from bottom to top. As a result, the cooling rate of the casting 5 gradually decreases from bottom to top. Therefore, the composite mold can be used to achieve the sequential solidification process of the casting 5 from bottom to top.

[0034] Of course, for casting 5, which has a more complex structure and higher requirements for solidification sequence, the cooling capacity of each part of the mold (sand mold and metal mold 1) should be gradient to meet the requirements of the solidification sequence of casting 5.

[0035] It is understood that the materials used in the composite mold include, but are not limited to, ceramsite sand, silica sand, chromite sand, zircon sand, metals, etc. Any material with different thermal conductivity and specific heat is within the protection scope of this invention.

[0036] Example 2:

[0037] This embodiment is for the casting of casting 5 of a cylindrical part with uniform wall thickness.

[0038] like Figure 2-4As shown in the figure, this invention discloses a composite mold for controlling the solidification sequence of castings, comprising multiple sand molds of different materials, which are assembled together vertically. In this embodiment, there are three sand molds: a ceramic sand mold 4, a silica sand mold 3, and a zircon sand mold 2, which are assembled from top to bottom. This invention controls the temperature field and solidification sequence of casting 5 by using molds of different materials at different positions on the casting 5 (different materials have different cooling effects on the casting 5; the molds are ordered from strongest to weakest cooling capacity as follows: metal mold 1 → zircon sand mold 2 → chromite sand mold 3 → silica sand mold 3 → ceramic sand mold 4). This achieves simple and convenient control of the solidification sequence of casting 5 while ensuring the quality of casting 5. The assembly method is flexible and adaptable, improving its applicability.

[0039] This invention also discloses a casting method using a composite mold for controlling the solidification sequence of castings, comprising the following steps:

[0040] According to the solidification sequence requirements of casting 5, multiple sand molds of different materials are assembled one above the other to regulate the temperature field of casting 5 during casting by utilizing the different cooling capacities of different materials, so that it solidifies in the required solidification sequence.

[0041] In the casting process of the cylindrical casting 5 with uniform wall thickness, a comparative experiment was conducted, using both existing sand molds (all existing sand molds are made of ceramsite sand) and the composite mold of this embodiment. To investigate the influence of the composite mold on the solidification sequence of the casting, the temperature field analysis of the top, middle, and bottom of the casting in both the existing sand mold and the composite mold of this embodiment was performed. It can be seen that in the existing sand mold, the top and bottom of the casting 5 solidify first, while the middle part solidifies last. This inevitably leads to the premature closure of the feeding channel of the riser at the top of the casting 5, causing shrinkage defects such as shrinkage cavities and porosity in the middle of the casting 5. However, after using the composite mold of this embodiment, the bottom of the casting 5 solidifies first, the middle part solidifies subsequently, and the top of the casting 5 solidifies last, forming a bottom-up solidification sequence. This is beneficial for the feeding of the casting 5 by the riser at the top of the casting 5, reducing shrinkage defects in the casting 5. This shows that the use of the composite mold can effectively control the temperature field and solidification sequence of the casting 5.

[0042] Example 3:

[0043] This embodiment is for casting of casting 5 with a relatively thin wall thickness in the middle (the cooling rate is relatively fast, which causes the feeding channel to close before the bottom of casting 5 is completely solidified, and the top riser cannot feed the bottom area of ​​casting 5).

[0044] like Figure 5As shown in the figure, this invention discloses a composite mold for controlling the solidification sequence of castings, comprising multiple sand molds of different materials, which are assembled together vertically. In this embodiment, there are three sand molds: a ceramic sand mold 4, a silica sand mold 3, and a zircon sand mold 2, which are assembled from top to bottom. This invention controls the temperature field and solidification sequence of castings 5 ​​by using molds of different materials at different positions on the casting 5 (different materials have different cooling effects on the casting 5; the molds are ordered from strongest to weakest cooling capacity as follows: metal mold 1 → zircon sand mold 2 → chromite sand mold 3 → silica sand mold 3 → ceramic sand mold 4). This achieves simple and convenient control of the solidification sequence of castings 5 ​​while ensuring the quality of the castings 5. The assembly method is flexible and adaptable, improving applicability.

[0045] This invention also discloses a casting method using a composite mold for controlling the solidification sequence of castings, comprising the following steps:

[0046] According to the solidification sequence requirements of casting 5, multiple sand molds of different materials are assembled one above the other to control the temperature field of casting 5 during casting by utilizing the different cooling capacities of different materials, so that it solidifies in the required solidification sequence. In this embodiment, zircon sand mold 2 can rapidly cool the bottom of casting 5, while the ceramsite sand mold 4 in the middle can slow down the cooling rate of the thin-walled area in the middle, and the silica sand mold 3 at the top allows the upper part of casting 5 to cool normally, ultimately forming a solidification sequence that gradually solidifies from bottom to top.

[0047] Example 4:

[0048] This embodiment is for casting of casting 5 with a relatively thick middle wall (the cooling rate is very slow, and it is the last part of casting 5 to solidify, so defects such as shrinkage cavities and porosity will inevitably occur in this part of casting 5).

[0049] like Figure 6 As shown in the figure, this invention discloses a composite mold for controlling the solidification sequence of castings, comprising multiple sand molds and metal molds of different materials, which are assembled together vertically. In this embodiment, there are two sand molds: a ceramic sand mold 4 and a silica sand mold 3, which are assembled from top to bottom. This invention controls the temperature field and solidification sequence of castings 5 ​​by using molds of different materials at different positions on the casting 5 (different materials have different cooling effects on the casting 5; the molds are ordered from strongest to weakest cooling capacity as follows: metal mold 1 → zircon sand mold 2 → chromite sand mold 3 → silica sand mold 3 → ceramic sand mold 4). This achieves simple and convenient control of the solidification sequence of castings 5 ​​while ensuring the quality of the castings 5. The assembly method is flexible and adaptable, improving applicability.

[0050] This invention also discloses a casting method using a composite mold for controlling the solidification sequence of castings, comprising the following steps:

[0051] According to the solidification sequence requirements of casting 5, multiple sand molds of different materials are assembled one above the other to control the temperature field of casting 5 during casting by utilizing the different cooling capacities of different materials, so that it solidifies in the required solidification sequence. In this embodiment, a silica sand mold 3 is used at the bottom of the casting to allow the bottom of casting 5 to cool normally, while a metal mold 1 is used for rapid cooling in the middle thick-walled area, and a ceramic aggregate sand mold 4 is used at the top of casting 5 for heat preservation and slow cooling, thereby achieving sequential solidification of casting 5 from bottom to top.

[0052] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0053] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A composite mold for controlling the solidification sequence of castings, characterized in that, include: Multiple sand molds made of different materials are assembled together, one on top of the other. Multiple sand molds and metal molds of different materials are assembled together.

2. The composite mold for controlling the solidification sequence of castings according to claim 1, characterized in that, The materials used in the sand mold include ceramsite sand, silica sand, chromite sand, and zircon sand.

3. A casting method using a composite mold for controlling the solidification sequence of castings as described in claim 1 or 2, characterized in that, Includes the following steps: According to the solidification sequence requirements of the casting, multiple sand molds of different materials are assembled vertically, or multiple sand molds and metal molds of different materials are assembled vertically, so as to control the temperature field of the casting by utilizing the different cooling capabilities of different materials during casting, so that it solidifies in the required solidification sequence.

4. The casting method according to claim 3, characterized in that, For casting areas that require accelerated cooling, metal molds and / or cooling sand molds are selected, with materials including zircon sand and chromite sand. For casting areas that require delayed cooling, insulating sand molds are selected, with materials including ceramsite sand and silica sand.

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