Manufacturing method of sand core for steel casting

Abstract

A manufacturing method of a sand core for a steel casting belongs to the technical field of casting, is used for solving the problem that special parts such as corners of the steel casting are easy to adhere to sand, and comprises the following steps: S01, constructing a sand mold with a casting cavity according to a casting pattern in three-dimensional modeling software, and splitting the sand mold according to a set parting surface to form a plurality of sand cores for manufacturing; s02, the structures, used for forming the corners, the narrow and small parts and the thick-wall parts of the casting, of the sand core are split, and a sand core body, a corner sand core, a narrow and small part sand core and a thick-wall part sand core are formed; the corner part sand core, the narrow part sand core and the thick wall part sand core have a sand sticking prevention function; and S03, transmitting the manufacturing data of the sand core in the step S02 to sand core manufacturing equipment, and manufacturing the sand core by the sand core manufacturing equipment according to the received data. According to the method, the risk or the problem of sand burning of corners, narrow parts and thick-wall parts of castings in the pouring process is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of casting, and in particular to a method for making a sand core. Background Art

[0002] Sand mold 3D printing technology has developed rapidly and matured in recent years, and has been widely used in various fields. It has the fast, convenient and flexible characteristics of 3D printing technology, and is different from metal 3D printing. It does not directly form the workpiece body, but participates in the production and manufacturing of castings in an indirect way. 3D printing does not require the design and production of molds, and the casting process design is more flexible, and there is no need to consider the demolding problem; in actual operation, sand core 3D printing can achieve overall printing and improve the accuracy of casting size, especially for complex structural castings, significantly reducing the number of sand cores and reducing the cumulative errors generated during the core assembly operation.

[0003] The raw sand commonly used in 3D printing is silica sand. Compared with the chromium ore sand used in traditional manual modeling, the thermal conductivity of silica sand is much different, and it is more likely to store heat and dissipate, resulting in serious sand sticking, especially in the R-angle parts of the upper crown and lower ring of some pumped storage semi-integral castings, the narrow airway parts of the steam turbine and expander volute, and the thick wall parts of the mining machine. The sand sticking problem is very prominent. The sand sticking problem is a very difficult problem for every foundry. Once sand sticking occurs, it is bound to have a serious impact on the appearance of the product. The finishing process requires a lot of manpower and material resources. Severe sand sticking may even cause the casting to be scrapped. Summary of the invention

[0004] In view of the fact that the sand cores made of the above silica sand are prone to sand sticking to the corners, narrow parts, thick-walled parts, etc. of the casting during the casting process, it is necessary to propose a method for making sand cores for steel castings, so that the surface quality and strength of the sand cores are better and the sand sticking problem of the castings is avoided.

[0005] A method for manufacturing a sand core for a steel casting, comprising:

[0006] S01, constructing a sand mold with a casting cavity according to a casting pattern in a three-dimensional modeling software, and core-dividing the sand mold according to a set parting surface to form a plurality of sand cores for production;

[0007] S02, splitting the structure of the sand core used to form the corner, narrow part and thick wall part of the casting into a sand core body and a corner sand core, a narrow part sand core and a thick wall sand core, etc.; and the corner sand core, the narrow part sand core and the thick wall sand core have an anti-sand sticking function, which effectively reduces the risk or problem of sand sticking to the corner, narrow part and thick wall part of the casting during the pouring process;

[0008] S03, transmitting the production data of the sand core in S02 to a sand core production device, such as a quicksand machine, a molding machine, a casting sand mold printer, etc., and the sand core production device produces the sand core according to the received data.

[0009] Furthermore, in S02, an inlay groove is provided at the position of the sand core body for assembling the corner sand core, the narrow part sand core and the thick-walled part sand core, and the inlay groove is used to perfectly match the sand core body with the corner sand core, the narrow part sand core and the thick-walled part sand core, so that the sand core body returns to a complete sand core for forming a casting cavity.

[0010] Furthermore, in order to prevent sand from sticking to the corners, narrow parts and thick-walled parts of the casting, the corner sand cores, narrow part sand cores and thick-walled part sand cores are made of chromium ore sand.

[0011] Furthermore, in order to ensure that the production cost does not increase significantly and cause the problem of too high a product price, the sand core body is made of silica sand, thereby effectively ensuring the cost of the sand core and preventing sand from sticking.

[0012] The beneficial effects of the technical solution of the present invention are as follows: by making sand cores for steel castings using two materials, not only is it ensured that the production cost of the sand cores will not be excessively increased, but it is also ensured that sand will not stick to the corners, narrow parts, thick-walled parts, etc. of the steel castings, thereby improving the surface quality of the castings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the upper crown structure of a steel casting turbine;

[0014] Figure 2 It is a schematic diagram of the sand core structure of the upper crown of the turbine;

[0015] Figure 3 is a schematic diagram of the inlay slot structure;

[0016] Figure 4 It is a schematic diagram of the corner sand core;

[0017] Figure 5 It is a schematic diagram of the sand core body and the corner sand core after assembly;

[0018] Among them, 1-turbine crown; 2-blade; 3-blade surface; 4-flow surface; 5-fillet; 6-inner ring sand core; 7-outer ring sand core; 8-sand core blade surface; 9-sand core flow surface; 10-sand core fillet; 12-inlay groove; 13-first fixing groove; 14-second fixing groove; 15-corner sand core; 16-first card slot; 17-second card slot; 20-inner ring sand core body, 18-outer ring sand core body, 21-narrow part sand core. DETAILED DESCRIPTION

[0019] In order to more clearly illustrate the technical solution of the present invention, the technical solution of the invention content is described in detail in conjunction with the accompanying drawings. Obviously, the following descriptions are some typical embodiments of the present invention. For ordinary technicians in this field, other solutions can be obtained based on these embodiments without paying creative work.

[0020] The present invention aims to solve the problem of sand sticking during the casting process of steel castings. The method adopted is to change the material of the sand core at the part prone to sand sticking from silica sand to chrome ore sand. In order to more clearly illustrate the implementation of the technical solution of the present invention, the specific implementation method of the present invention is now described by taking the turbine upper crown casting as an example.

[0021] In one implementation mode, the sand core for casting of a water turbine upper crown is manufactured by using the method for manufacturing the sand core for steel castings, and the specific implementation process is as follows:

[0022] S11, constructing a sand mold for forming the turbine crown in a three-dimensional modeling software according to the drawing of the turbine crown to be cast provided by the customer; dividing the sand mold of the turbine crown according to the casting process and the sand core making process to form a plurality of sand cores for making; in this embodiment, the sand core includes a plurality of inner ring sand cores 6 and a plurality of outer ring sand cores 7;

[0023] S12, detaching the structures on the inner ring sand core 6 and the outer ring sand core 7 for forming the corner, narrow part and thick wall part of the casting from the inner ring sand core 6 and the outer ring sand core 7, that is, separating the inner ring sand core 6 and the outer ring sand core 7 into the inner ring sand core body 20, the outer ring sand core body 18, the corner sand core 15, the narrow part sand core 21 and the thick wall part sand core; and the corner sand core 15, the narrow part sand core 21 and the thick wall part sand core have the function of preventing sand from sticking;

[0024] S13, providing an inlay groove 12 at the position where the inner ring sand core body and the outer ring sand core body are used to assemble the corner sand core, the narrow part sand core and the thick wall part sand core, and the inlay groove 12 is used to firmly fit the corner sand core, the narrow part sand core and the thick wall part sand core on the inner ring sand core body and the outer ring sand core body;

[0025] S14, transmitting the sand core making data in S13 to the sand core making equipment. In the present embodiment, the sand core making equipment is a casting sand mold printer. After receiving the sand core making data, the casting sand mold printer prints the inner circle sand core body, outer circle sand core body, corner sand core, narrow part sand core and thick wall part sand core according to the sand core making data to form the sand core of the casting cavity.

[0026] As a supplement to the present embodiment, the inlay groove 12 includes a first fixing groove 13 and a second fixing groove 14 for clamping the corner sand 15, the narrow part sand core 21 and the thick wall part sand core. The first fixing groove 13 and the second fixing groove 14 can be used to well match the separated independent sand cores such as the corner sand 15, the narrow part sand core 21 and the thick wall part sand core on the inner ring sand core body 20 and the outer ring sand core body 18 to form a sand core that completely constitutes the casting cavity to be produced. The first fixing groove 13 and the second fixing groove 14 can effectively prevent the corner sand 15, the narrow part sand core 21 and the thick wall part sand core assembled on the inner ring sand core body 20 and the outer ring sand core body 18 from drifting or falling off due to the buoyancy of the molten metal during the pouring process, causing the problem of unqualified casting structure.

[0027] As a supplement to the present embodiment, similarly, the separated corner sand core 15, the narrow part sand core 21 and the thick wall part sand core are also provided with a first card groove 16 and a second card groove 17 which cooperate with the first fixed groove 13 and the second fixed groove 14. Specifically, the first fixed groove 13 cooperates with the first card groove 16, and the second fixed groove 14 cooperates with the second card groove 17, so as to effectively connect the corner sand core 15 to the outer ring sand core body 18.

[0028] As a further supplement to the present embodiment, the first clamping groove 16 is arranged on the side surface of the corner sand core 15 facing the sand core body, and the second clamping groove 17 is arranged at the lower part of the corner sand core 15 and is arranged in a T-shape to achieve the purpose of counteracting the buoyancy of the molten metal in the vertical direction, play a role of hanging, and prevent the corner sand core 15 from floating or falling off during the pouring process.

[0029] As a supplement to the present embodiment, the corner sand core 15, the narrow part sand core 21 and the thick wall part sand core are made of chrome ore sand. The corner sand core, the narrow part sand core and the thick wall part sand core made of the chrome ore sand have good anti-sand sticking function, thereby effectively achieving the purpose of the present invention.

[0030] As a supplement to this embodiment, under the condition that the corners, narrow parts and thick wall parts of the casting that are easy to be stuck with sand are not stuck with sand, in order not to significantly increase the production cost of the sand core, the sand core body is made of silica sand. In this embodiment, the inner ring sand core body 20 and the outer ring sand core body 18 are both made of silica sand.

[0031] As a supplement to the present embodiment, in order to improve the overall production progress or efficiency of the sand core, the sand core body is manufactured by the sand core manufacturing equipment, and the corner sand core, narrow sand core and thick-wall sand core are separated and independent sand cores are manufactured using chromium ore sand. Since the independent sand core is small in volume and the chromium ore sand is dense, in the present embodiment, the corner sand core, narrow sand core and thick-wall sand core are manually manufactured, that is, the corner sand core, narrow sand core and thick-wall sand core are manually made by operators.

[0032] As a further supplement to the present embodiment, the longest dimension of the corner sand core, the narrow part sand core and the thick-walled part sand core does not exceed 600 mm, and the maximum weight does not exceed 25 kg. That is, the corner sand core, the narrow part sand core and the thick-walled part sand core are made small and light to facilitate installation and avoid damage to the independent sand core during production, transportation and installation.

[0033] The above embodiments are merely descriptions of a typical application of the technical solution of the present invention, and reasonable expansion can be carried out on a reasonable basis without requiring creative work.

Claims

1. A method for making a sand core for a steel casting, It is characterized in that include, S01, constructing a sand mold with a casting cavity according to a casting pattern in a three-dimensional modeling software, and core-dividing the sand mold according to a set parting surface to form a plurality of sand cores for production; S02, splitting the structure of the sand core used to form the corner, narrow part and thick wall part of the casting to form a sand core body and a corner sand core (15), a narrow part sand core (21) and a thick wall sand core; and the corner sand core (15), the narrow part sand core (21) and the thick wall sand core have the function of preventing sand from sticking; S03, transmitting the sand core making data in S02 to a sand core making device, and the sand core making device makes the sand core according to the received data.

2. The method for making a sand core for a steel casting according to claim 1, It is characterized in that The corner sand core (15), the narrow portion sand core (21) and the thick wall portion sand core are made of chromium ore sand.

3. The method for making a sand core for a steel casting according to claim 1, It is characterized in that The sand core body is made of silica sand.

4. A method for making a sand core for a steel casting according to any one of claims 1 to 3, It is characterized in that The sand core body is provided with an inlay groove (12) at a position where the corner sand core (15), the narrow part sand core (21) and the thick wall part sand core are assembled. The inlay groove (12) is used to perfectly match the sand core body with the corner sand core (15), the narrow part sand core (21) and the thick wall part sand core, so that the sand core body is completely restored to form a sand core of the casting cavity.

5. The method for making a sand core for a steel casting according to claim 4, It is characterized in that The inlay groove (12) comprises a first fixing groove (13) and a second fixing groove (14) for clamping the corner sand, the narrow part sand core (21) and the thick wall part sand core. The first fixing groove (13) and the second fixing groove (14) can be used to well match the separated independent sand cores such as the corner sand, the narrow part sand core (21) and the thick wall part sand core on the inner circle sand core body and the outer circle sand core body to form a sand core that completely constitutes the casting cavity to be produced.

6. The method for making a sand core for a steel casting according to claim 5, It is characterized in that The separated corner sand core (15), narrow portion sand core (21) and thick wall portion sand core are also provided with a first clamping groove (16) and a second clamping groove (17) which cooperate with the first fixing groove (13) and the second fixing groove (14).

7. The method for making a sand core for a steel casting according to claim 6, It is characterized in that The first fixing groove (13) cooperates with the first clamping groove (16), and the second fixing groove (14) cooperates with the second clamping groove (17).

8. The method for making a sand core for a steel casting according to claim 5, It is characterized in that The first clamping groove (16) is arranged on a side surface of the corner sand core (15) facing the sand core body, and the second clamping groove (17) is arranged at the lower part of the corner sand core (15) and is arranged in a T-shape.

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